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linux/security/smack/smack_lsm.c
Casey Schaufler 69f287ae6f Smack: secmark support for netfilter 
Smack uses CIPSO to label internet packets and thus provide
for access control on delivery of packets. The netfilter facility
was not used to allow for Smack to work properly without netfilter
configuration. Smack does not need netfilter, however there are
cases where it would be handy.

As a side effect, the labeling of local IPv4 packets can be optimized
and the handling of local IPv6 packets is just all out better.

The best part is that the netfilter tools use "contexts" that
are just strings, and they work just as well for Smack as they
do for SELinux.

All of the conditional compilation for IPv6 was implemented
by Rafal Krypa <r.krypa@samsung.com>

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2015-01-20 16:34:25 -08:00

4397 lines
104 KiB
C
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/*
* Simplified MAC Kernel (smack) security module
*
* This file contains the smack hook function implementations.
*
* Authors:
* Casey Schaufler <casey@schaufler-ca.com>
* Jarkko Sakkinen <jarkko.sakkinen@intel.com>
*
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul@paul-moore.com>
* Copyright (C) 2010 Nokia Corporation
* Copyright (C) 2011 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
* as published by the Free Software Foundation.
*/
#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/cipso_ipv4.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/audit.h>
#include <linux/magic.h>
#include <linux/dcache.h>
#include <linux/personality.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/binfmts.h>
#include "smack.h"
#define task_security(task) (task_cred_xxx((task), security))
#define TRANS_TRUE "TRUE"
#define TRANS_TRUE_SIZE 4
#define SMK_CONNECTING 0
#define SMK_RECEIVING 1
#define SMK_SENDING 2
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
LIST_HEAD(smk_ipv6_port_list);
#endif /* CONFIG_IPV6 && !CONFIG_SECURITY_SMACK_NETFILTER */
static struct kmem_cache *smack_inode_cache;
int smack_enabled;
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static void smk_bu_mode(int mode, char *s)
{
int i = 0;
if (mode & MAY_READ)
s[i++] = 'r';
if (mode & MAY_WRITE)
s[i++] = 'w';
if (mode & MAY_EXEC)
s[i++] = 'x';
if (mode & MAY_APPEND)
s[i++] = 'a';
if (mode & MAY_TRANSMUTE)
s[i++] = 't';
if (mode & MAY_LOCK)
s[i++] = 'l';
if (i == 0)
s[i++] = '-';
s[i] = '\0';
}
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_note(char *note, struct smack_known *sskp,
struct smack_known *oskp, int mode, int rc)
{
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
smk_bu_mode(mode, acc);
pr_info("Smack Bringup: (%s %s %s) %s\n",
sskp->smk_known, oskp->smk_known, acc, note);
return 0;
}
#else
#define smk_bu_note(note, sskp, oskp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_current(char *note, struct smack_known *oskp,
int mode, int rc)
{
struct task_smack *tsp = current_security();
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
smk_bu_mode(mode, acc);
pr_info("Smack Bringup: (%s %s %s) %s %s\n",
tsp->smk_task->smk_known, oskp->smk_known,
acc, current->comm, note);
return 0;
}
#else
#define smk_bu_current(note, oskp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_task(struct task_struct *otp, int mode, int rc)
{
struct task_smack *tsp = current_security();
struct task_smack *otsp = task_security(otp);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
smk_bu_mode(mode, acc);
pr_info("Smack Bringup: (%s %s %s) %s to %s\n",
tsp->smk_task->smk_known, otsp->smk_task->smk_known, acc,
current->comm, otp->comm);
return 0;
}
#else
#define smk_bu_task(otp, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_inode(struct inode *inode, int mode, int rc)
{
struct task_smack *tsp = current_security();
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
smk_bu_mode(mode, acc);
pr_info("Smack Bringup: (%s %s %s) inode=(%s %ld) %s\n",
tsp->smk_task->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, current->comm);
return 0;
}
#else
#define smk_bu_inode(inode, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_file(struct file *file, int mode, int rc)
{
struct task_smack *tsp = current_security();
struct smack_known *sskp = tsp->smk_task;
struct inode *inode = file_inode(file);
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
smk_bu_mode(mode, acc);
pr_info("Smack Bringup: (%s %s %s) file=(%s %ld %pD) %s\n",
sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, file,
current->comm);
return 0;
}
#else
#define smk_bu_file(file, mode, RC) (RC)
#endif
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_credfile(const struct cred *cred, struct file *file,
int mode, int rc)
{
struct task_smack *tsp = cred->security;
struct smack_known *sskp = tsp->smk_task;
struct inode *inode = file->f_inode;
char acc[SMK_NUM_ACCESS_TYPE + 1];
if (rc <= 0)
return rc;
smk_bu_mode(mode, acc);
pr_info("Smack Bringup: (%s %s %s) file=(%s %ld %pD) %s\n",
sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
inode->i_sb->s_id, inode->i_ino, file,
current->comm);
return 0;
}
#else
#define smk_bu_credfile(cred, file, mode, RC) (RC)
#endif
/**
* smk_fetch - Fetch the smack label from a file.
* @name: type of the label (attribute)
* @ip: a pointer to the inode
* @dp: a pointer to the dentry
*
* Returns a pointer to the master list entry for the Smack label
* or NULL if there was no label to fetch.
*/
static struct smack_known *smk_fetch(const char *name, struct inode *ip,
struct dentry *dp)
{
int rc;
char *buffer;
struct smack_known *skp = NULL;
if (ip->i_op->getxattr == NULL)
return NULL;
buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
if (buffer == NULL)
return NULL;
rc = ip->i_op->getxattr(dp, name, buffer, SMK_LONGLABEL);
if (rc > 0)
skp = smk_import_entry(buffer, rc);
kfree(buffer);
return skp;
}
/**
* new_inode_smack - allocate an inode security blob
* @skp: a pointer to the Smack label entry to use in the blob
*
* Returns the new blob or NULL if there's no memory available
*/
struct inode_smack *new_inode_smack(struct smack_known *skp)
{
struct inode_smack *isp;
isp = kmem_cache_zalloc(smack_inode_cache, GFP_NOFS);
if (isp == NULL)
return NULL;
isp->smk_inode = skp;
isp->smk_flags = 0;
mutex_init(&isp->smk_lock);
return isp;
}
/**
* new_task_smack - allocate a task security blob
* @task: a pointer to the Smack label for the running task
* @forked: a pointer to the Smack label for the forked task
* @gfp: type of the memory for the allocation
*
* Returns the new blob or NULL if there's no memory available
*/
static struct task_smack *new_task_smack(struct smack_known *task,
struct smack_known *forked, gfp_t gfp)
{
struct task_smack *tsp;
tsp = kzalloc(sizeof(struct task_smack), gfp);
if (tsp == NULL)
return NULL;
tsp->smk_task = task;
tsp->smk_forked = forked;
INIT_LIST_HEAD(&tsp->smk_rules);
mutex_init(&tsp->smk_rules_lock);
return tsp;
}
/**
* smk_copy_rules - copy a rule set
* @nhead: new rules header pointer
* @ohead: old rules header pointer
* @gfp: type of the memory for the allocation
*
* Returns 0 on success, -ENOMEM on error
*/
static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
gfp_t gfp)
{
struct smack_rule *nrp;
struct smack_rule *orp;
int rc = 0;
INIT_LIST_HEAD(nhead);
list_for_each_entry_rcu(orp, ohead, list) {
nrp = kzalloc(sizeof(struct smack_rule), gfp);
if (nrp == NULL) {
rc = -ENOMEM;
break;
}
*nrp = *orp;
list_add_rcu(&nrp->list, nhead);
}
return rc;
}
/**
* smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
* @mode - input mode in form of PTRACE_MODE_*
*
* Returns a converted MAY_* mode usable by smack rules
*/
static inline unsigned int smk_ptrace_mode(unsigned int mode)
{
switch (mode) {
case PTRACE_MODE_READ:
return MAY_READ;
case PTRACE_MODE_ATTACH:
return MAY_READWRITE;
}
return 0;
}
/**
* smk_ptrace_rule_check - helper for ptrace access
* @tracer: tracer process
* @tracee_known: label entry of the process that's about to be traced
* @mode: ptrace attachment mode (PTRACE_MODE_*)
* @func: name of the function that called us, used for audit
*
* Returns 0 on access granted, -error on error
*/
static int smk_ptrace_rule_check(struct task_struct *tracer,
struct smack_known *tracee_known,
unsigned int mode, const char *func)
{
int rc;
struct smk_audit_info ad, *saip = NULL;
struct task_smack *tsp;
struct smack_known *tracer_known;
if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, tracer);
saip = &ad;
}
tsp = task_security(tracer);
tracer_known = smk_of_task(tsp);
if ((mode & PTRACE_MODE_ATTACH) &&
(smack_ptrace_rule == SMACK_PTRACE_EXACT ||
smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
if (tracer_known->smk_known == tracee_known->smk_known)
rc = 0;
else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
rc = -EACCES;
else if (capable(CAP_SYS_PTRACE))
rc = 0;
else
rc = -EACCES;
if (saip)
smack_log(tracer_known->smk_known,
tracee_known->smk_known,
0, rc, saip);
return rc;
}
/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
return rc;
}
/*
* LSM hooks.
* We he, that is fun!
*/
/**
* smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
* @ctp: child task pointer
* @mode: ptrace attachment mode (PTRACE_MODE_*)
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks.
*/
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
int rc;
struct smack_known *skp;
rc = cap_ptrace_access_check(ctp, mode);
if (rc != 0)
return rc;
skp = smk_of_task(task_security(ctp));
rc = smk_ptrace_rule_check(current, skp, mode, __func__);
return rc;
}
/**
* smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
* @ptp: parent task pointer
*
* Returns 0 if access is OK, an error code otherwise
*
* Do the capability checks, and require PTRACE_MODE_ATTACH.
*/
static int smack_ptrace_traceme(struct task_struct *ptp)
{
int rc;
struct smack_known *skp;
rc = cap_ptrace_traceme(ptp);
if (rc != 0)
return rc;
skp = smk_of_task(current_security());
rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
return rc;
}
/**
* smack_syslog - Smack approval on syslog
* @type: message type
*
* Returns 0 on success, error code otherwise.
*/
static int smack_syslog(int typefrom_file)
{
int rc = 0;
struct smack_known *skp = smk_of_current();
if (smack_privileged(CAP_MAC_OVERRIDE))
return 0;
if (smack_syslog_label != NULL && smack_syslog_label != skp)
rc = -EACCES;
return rc;
}
/*
* Superblock Hooks.
*/
/**
* smack_sb_alloc_security - allocate a superblock blob
* @sb: the superblock getting the blob
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_sb_alloc_security(struct super_block *sb)
{
struct superblock_smack *sbsp;
sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);
if (sbsp == NULL)
return -ENOMEM;
sbsp->smk_root = &smack_known_floor;
sbsp->smk_default = &smack_known_floor;
sbsp->smk_floor = &smack_known_floor;
sbsp->smk_hat = &smack_known_hat;
/*
* smk_initialized will be zero from kzalloc.
*/
sb->s_security = sbsp;
return 0;
}
/**
* smack_sb_free_security - free a superblock blob
* @sb: the superblock getting the blob
*
*/
static void smack_sb_free_security(struct super_block *sb)
{
kfree(sb->s_security);
sb->s_security = NULL;
}
/**
* smack_sb_copy_data - copy mount options data for processing
* @orig: where to start
* @smackopts: mount options string
*
* Returns 0 on success or -ENOMEM on error.
*
* Copy the Smack specific mount options out of the mount
* options list.
*/
static int smack_sb_copy_data(char *orig, char *smackopts)
{
char *cp, *commap, *otheropts, *dp;
otheropts = (char *)get_zeroed_page(GFP_KERNEL);
if (otheropts == NULL)
return -ENOMEM;
for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
if (strstr(cp, SMK_FSDEFAULT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSFLOOR) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSHAT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSROOT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSTRANS) == cp)
dp = smackopts;
else
dp = otheropts;
commap = strchr(cp, ',');
if (commap != NULL)
*commap = '\0';
if (*dp != '\0')
strcat(dp, ",");
strcat(dp, cp);
}
strcpy(orig, otheropts);
free_page((unsigned long)otheropts);
return 0;
}
/**
* smack_sb_kern_mount - Smack specific mount processing
* @sb: the file system superblock
* @flags: the mount flags
* @data: the smack mount options
*
* Returns 0 on success, an error code on failure
*/
static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
{
struct dentry *root = sb->s_root;
struct inode *inode = root->d_inode;
struct superblock_smack *sp = sb->s_security;
struct inode_smack *isp;
struct smack_known *skp;
char *op;
char *commap;
int transmute = 0;
int specified = 0;
if (sp->smk_initialized)
return 0;
sp->smk_initialized = 1;
for (op = data; op != NULL; op = commap) {
commap = strchr(op, ',');
if (commap != NULL)
*commap++ = '\0';
if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
op += strlen(SMK_FSHAT);
skp = smk_import_entry(op, 0);
if (skp != NULL) {
sp->smk_hat = skp;
specified = 1;
}
} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
op += strlen(SMK_FSFLOOR);
skp = smk_import_entry(op, 0);
if (skp != NULL) {
sp->smk_floor = skp;
specified = 1;
}
} else if (strncmp(op, SMK_FSDEFAULT,
strlen(SMK_FSDEFAULT)) == 0) {
op += strlen(SMK_FSDEFAULT);
skp = smk_import_entry(op, 0);
if (skp != NULL) {
sp->smk_default = skp;
specified = 1;
}
} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
op += strlen(SMK_FSROOT);
skp = smk_import_entry(op, 0);
if (skp != NULL) {
sp->smk_root = skp;
specified = 1;
}
} else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
op += strlen(SMK_FSTRANS);
skp = smk_import_entry(op, 0);
if (skp != NULL) {
sp->smk_root = skp;
transmute = 1;
specified = 1;
}
}
}
if (!smack_privileged(CAP_MAC_ADMIN)) {
/*
* Unprivileged mounts don't get to specify Smack values.
*/
if (specified)
return -EPERM;
/*
* Unprivileged mounts get root and default from the caller.
*/
skp = smk_of_current();
sp->smk_root = skp;
sp->smk_default = skp;
}
/*
* Initialize the root inode.
*/
isp = inode->i_security;
if (isp == NULL) {
isp = new_inode_smack(sp->smk_root);
if (isp == NULL)
return -ENOMEM;
inode->i_security = isp;
} else
isp->smk_inode = sp->smk_root;
if (transmute)
isp->smk_flags |= SMK_INODE_TRANSMUTE;
return 0;
}
/**
* smack_sb_statfs - Smack check on statfs
* @dentry: identifies the file system in question
*
* Returns 0 if current can read the floor of the filesystem,
* and error code otherwise
*/
static int smack_sb_statfs(struct dentry *dentry)
{
struct superblock_smack *sbp = dentry->d_sb->s_security;
int rc;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
return rc;
}
/*
* BPRM hooks
*/
/**
* smack_bprm_set_creds - set creds for exec
* @bprm: the exec information
*
* Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
*/
static int smack_bprm_set_creds(struct linux_binprm *bprm)
{
struct inode *inode = file_inode(bprm->file);
struct task_smack *bsp = bprm->cred->security;
struct inode_smack *isp;
int rc;
rc = cap_bprm_set_creds(bprm);
if (rc != 0)
return rc;
if (bprm->cred_prepared)
return 0;
isp = inode->i_security;
if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
return 0;
if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
struct task_struct *tracer;
rc = 0;
rcu_read_lock();
tracer = ptrace_parent(current);
if (likely(tracer != NULL))
rc = smk_ptrace_rule_check(tracer,
isp->smk_task,
PTRACE_MODE_ATTACH,
__func__);
rcu_read_unlock();
if (rc != 0)
return rc;
} else if (bprm->unsafe)
return -EPERM;
bsp->smk_task = isp->smk_task;
bprm->per_clear |= PER_CLEAR_ON_SETID;
return 0;
}
/**
* smack_bprm_committing_creds - Prepare to install the new credentials
* from bprm.
*
* @bprm: binprm for exec
*/
static void smack_bprm_committing_creds(struct linux_binprm *bprm)
{
struct task_smack *bsp = bprm->cred->security;
if (bsp->smk_task != bsp->smk_forked)
current->pdeath_signal = 0;
}
/**
* smack_bprm_secureexec - Return the decision to use secureexec.
* @bprm: binprm for exec
*
* Returns 0 on success.
*/
static int smack_bprm_secureexec(struct linux_binprm *bprm)
{
struct task_smack *tsp = current_security();
int ret = cap_bprm_secureexec(bprm);
if (!ret && (tsp->smk_task != tsp->smk_forked))
ret = 1;
return ret;
}
/*
* Inode hooks
*/
/**
* smack_inode_alloc_security - allocate an inode blob
* @inode: the inode in need of a blob
*
* Returns 0 if it gets a blob, -ENOMEM otherwise
*/
static int smack_inode_alloc_security(struct inode *inode)
{
struct smack_known *skp = smk_of_current();
inode->i_security = new_inode_smack(skp);
if (inode->i_security == NULL)
return -ENOMEM;
return 0;
}
/**
* smack_inode_free_security - free an inode blob
* @inode: the inode with a blob
*
* Clears the blob pointer in inode
*/
static void smack_inode_free_security(struct inode *inode)
{
kmem_cache_free(smack_inode_cache, inode->i_security);
inode->i_security = NULL;
}
/**
* smack_inode_init_security - copy out the smack from an inode
* @inode: the newly created inode
* @dir: containing directory object
* @qstr: unused
* @name: where to put the attribute name
* @value: where to put the attribute value
* @len: where to put the length of the attribute
*
* Returns 0 if it all works out, -ENOMEM if there's no memory
*/
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr, const char **name,
void **value, size_t *len)
{
struct inode_smack *issp = inode->i_security;
struct smack_known *skp = smk_of_current();
struct smack_known *isp = smk_of_inode(inode);
struct smack_known *dsp = smk_of_inode(dir);
int may;
if (name)
*name = XATTR_SMACK_SUFFIX;
if (value && len) {
rcu_read_lock();
may = smk_access_entry(skp->smk_known, dsp->smk_known,
&skp->smk_rules);
rcu_read_unlock();
/*
* If the access rule allows transmutation and
* the directory requests transmutation then
* by all means transmute.
* Mark the inode as changed.
*/
if (may > 0 && ((may & MAY_TRANSMUTE) != 0) &&
smk_inode_transmutable(dir)) {
isp = dsp;
issp->smk_flags |= SMK_INODE_CHANGED;
}
*value = kstrdup(isp->smk_known, GFP_NOFS);
if (*value == NULL)
return -ENOMEM;
*len = strlen(isp->smk_known);
}
return 0;
}
/**
* smack_inode_link - Smack check on link
* @old_dentry: the existing object
* @dir: unused
* @new_dentry: the new object
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *new_dentry)
{
struct smack_known *isp;
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
isp = smk_of_inode(old_dentry->d_inode);
rc = smk_curacc(isp, MAY_WRITE, &ad);
rc = smk_bu_inode(old_dentry->d_inode, MAY_WRITE, rc);
if (rc == 0 && new_dentry->d_inode != NULL) {
isp = smk_of_inode(new_dentry->d_inode);
smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
rc = smk_curacc(isp, MAY_WRITE, &ad);
rc = smk_bu_inode(new_dentry->d_inode, MAY_WRITE, rc);
}
return rc;
}
/**
* smack_inode_unlink - Smack check on inode deletion
* @dir: containing directory object
* @dentry: file to unlink
*
* Returns 0 if current can write the containing directory
* and the object, error code otherwise
*/
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *ip = dentry->d_inode;
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
/*
* You need write access to the thing you're unlinking
*/
rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
rc = smk_bu_inode(ip, MAY_WRITE, rc);
if (rc == 0) {
/*
* You also need write access to the containing directory
*/
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, dir);
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
rc = smk_bu_inode(dir, MAY_WRITE, rc);
}
return rc;
}
/**
* smack_inode_rmdir - Smack check on directory deletion
* @dir: containing directory object
* @dentry: directory to unlink
*
* Returns 0 if current can write the containing directory
* and the directory, error code otherwise
*/
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
/*
* You need write access to the thing you're removing
*/
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
if (rc == 0) {
/*
* You also need write access to the containing directory
*/
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, dir);
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
rc = smk_bu_inode(dir, MAY_WRITE, rc);
}
return rc;
}
/**
* smack_inode_rename - Smack check on rename
* @old_inode: unused
* @old_dentry: the old object
* @new_inode: unused
* @new_dentry: the new object
*
* Read and write access is required on both the old and
* new directories.
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_rename(struct inode *old_inode,
struct dentry *old_dentry,
struct inode *new_inode,
struct dentry *new_dentry)
{
int rc;
struct smack_known *isp;
struct smk_audit_info ad;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
isp = smk_of_inode(old_dentry->d_inode);
rc = smk_curacc(isp, MAY_READWRITE, &ad);
rc = smk_bu_inode(old_dentry->d_inode, MAY_READWRITE, rc);
if (rc == 0 && new_dentry->d_inode != NULL) {
isp = smk_of_inode(new_dentry->d_inode);
smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
rc = smk_curacc(isp, MAY_READWRITE, &ad);
rc = smk_bu_inode(new_dentry->d_inode, MAY_READWRITE, rc);
}
return rc;
}
/**
* smack_inode_permission - Smack version of permission()
* @inode: the inode in question
* @mask: the access requested
*
* This is the important Smack hook.
*
* Returns 0 if access is permitted, -EACCES otherwise
*/
static int smack_inode_permission(struct inode *inode, int mask)
{
struct smk_audit_info ad;
int no_block = mask & MAY_NOT_BLOCK;
int rc;
mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
/*
* No permission to check. Existence test. Yup, it's there.
*/
if (mask == 0)
return 0;
/* May be droppable after audit */
if (no_block)
return -ECHILD;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, inode);
rc = smk_curacc(smk_of_inode(inode), mask, &ad);
rc = smk_bu_inode(inode, mask, rc);
return rc;
}
/**
* smack_inode_setattr - Smack check for setting attributes
* @dentry: the object
* @iattr: for the force flag
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct smk_audit_info ad;
int rc;
/*
* Need to allow for clearing the setuid bit.
*/
if (iattr->ia_valid & ATTR_FORCE)
return 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
return rc;
}
/**
* smack_inode_getattr - Smack check for getting attributes
* @mnt: vfsmount of the object
* @dentry: the object
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
struct smk_audit_info ad;
struct path path;
int rc;
path.dentry = dentry;
path.mnt = mnt;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, path);
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
rc = smk_bu_inode(dentry->d_inode, MAY_READ, rc);
return rc;
}
/**
* smack_inode_setxattr - Smack check for setting xattrs
* @dentry: the object
* @name: name of the attribute
* @value: value of the attribute
* @size: size of the value
* @flags: unused
*
* This protects the Smack attribute explicitly.
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct smk_audit_info ad;
struct smack_known *skp;
int check_priv = 0;
int check_import = 0;
int check_star = 0;
int rc = 0;
/*
* Check label validity here so import won't fail in post_setxattr
*/
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
check_priv = 1;
check_import = 1;
} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
check_priv = 1;
check_import = 1;
check_star = 1;
} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
check_priv = 1;
if (size != TRANS_TRUE_SIZE ||
strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
rc = -EINVAL;
} else
rc = cap_inode_setxattr(dentry, name, value, size, flags);
if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
rc = -EPERM;
if (rc == 0 && check_import) {
skp = size ? smk_import_entry(value, size) : NULL;
if (skp == NULL || (check_star &&
(skp == &smack_known_star || skp == &smack_known_web)))
rc = -EINVAL;
}
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
if (rc == 0) {
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
}
return rc;
}
/**
* smack_inode_post_setxattr - Apply the Smack update approved above
* @dentry: object
* @name: attribute name
* @value: attribute value
* @size: attribute size
* @flags: unused
*
* Set the pointer in the inode blob to the entry found
* in the master label list.
*/
static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct smack_known *skp;
struct inode_smack *isp = dentry->d_inode->i_security;
if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
isp->smk_flags |= SMK_INODE_TRANSMUTE;
return;
}
if (strcmp(name, XATTR_NAME_SMACK) == 0) {
skp = smk_import_entry(value, size);
if (skp != NULL)
isp->smk_inode = skp;
else
isp->smk_inode = &smack_known_invalid;
} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
skp = smk_import_entry(value, size);
if (skp != NULL)
isp->smk_task = skp;
else
isp->smk_task = &smack_known_invalid;
} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
skp = smk_import_entry(value, size);
if (skp != NULL)
isp->smk_mmap = skp;
else
isp->smk_mmap = &smack_known_invalid;
}
return;
}
/**
* smack_inode_getxattr - Smack check on getxattr
* @dentry: the object
* @name: unused
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_getxattr(struct dentry *dentry, const char *name)
{
struct smk_audit_info ad;
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
rc = smk_bu_inode(dentry->d_inode, MAY_READ, rc);
return rc;
}
/**
* smack_inode_removexattr - Smack check on removexattr
* @dentry: the object
* @name: name of the attribute
*
* Removing the Smack attribute requires CAP_MAC_ADMIN
*
* Returns 0 if access is permitted, an error code otherwise
*/
static int smack_inode_removexattr(struct dentry *dentry, const char *name)
{
struct inode_smack *isp;
struct smk_audit_info ad;
int rc = 0;
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
if (!smack_privileged(CAP_MAC_ADMIN))
rc = -EPERM;
} else
rc = cap_inode_removexattr(dentry, name);
if (rc != 0)
return rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
if (rc != 0)
return rc;
isp = dentry->d_inode->i_security;
/*
* Don't do anything special for these.
* XATTR_NAME_SMACKIPIN
* XATTR_NAME_SMACKIPOUT
* XATTR_NAME_SMACKEXEC
*/
if (strcmp(name, XATTR_NAME_SMACK) == 0)
isp->smk_task = NULL;
else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
isp->smk_mmap = NULL;
else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
isp->smk_flags &= ~SMK_INODE_TRANSMUTE;
return 0;
}
/**
* smack_inode_getsecurity - get smack xattrs
* @inode: the object
* @name: attribute name
* @buffer: where to put the result
* @alloc: unused
*
* Returns the size of the attribute or an error code
*/
static int smack_inode_getsecurity(const struct inode *inode,
const char *name, void **buffer,
bool alloc)
{
struct socket_smack *ssp;
struct socket *sock;
struct super_block *sbp;
struct inode *ip = (struct inode *)inode;
struct smack_known *isp;
int ilen;
int rc = 0;
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
isp = smk_of_inode(inode);
ilen = strlen(isp->smk_known);
*buffer = isp->smk_known;
return ilen;
}
/*
* The rest of the Smack xattrs are only on sockets.
*/
sbp = ip->i_sb;
if (sbp->s_magic != SOCKFS_MAGIC)
return -EOPNOTSUPP;
sock = SOCKET_I(ip);
if (sock == NULL || sock->sk == NULL)
return -EOPNOTSUPP;
ssp = sock->sk->sk_security;
if (strcmp(name, XATTR_SMACK_IPIN) == 0)
isp = ssp->smk_in;
else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
isp = ssp->smk_out;
else
return -EOPNOTSUPP;
ilen = strlen(isp->smk_known);
if (rc == 0) {
*buffer = isp->smk_known;
rc = ilen;
}
return rc;
}
/**
* smack_inode_listsecurity - list the Smack attributes
* @inode: the object
* @buffer: where they go
* @buffer_size: size of buffer
*
* Returns 0 on success, -EINVAL otherwise
*/
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
size_t buffer_size)
{
int len = sizeof(XATTR_NAME_SMACK);
if (buffer != NULL && len <= buffer_size)
memcpy(buffer, XATTR_NAME_SMACK, len);
return len;
}
/**
* smack_inode_getsecid - Extract inode's security id
* @inode: inode to extract the info from
* @secid: where result will be saved
*/
static void smack_inode_getsecid(const struct inode *inode, u32 *secid)
{
struct inode_smack *isp = inode->i_security;
*secid = isp->smk_inode->smk_secid;
}
/*
* File Hooks
*/
/**
* smack_file_permission - Smack check on file operations
* @file: unused
* @mask: unused
*
* Returns 0
*
* Should access checks be done on each read or write?
* UNICOS and SELinux say yes.
* Trusted Solaris, Trusted Irix, and just about everyone else says no.
*
* I'll say no for now. Smack does not do the frequent
* label changing that SELinux does.
*/
static int smack_file_permission(struct file *file, int mask)
{
return 0;
}
/**
* smack_file_alloc_security - assign a file security blob
* @file: the object
*
* The security blob for a file is a pointer to the master
* label list, so no allocation is done.
*
* f_security is the owner security information. It
* isn't used on file access checks, it's for send_sigio.
*
* Returns 0
*/
static int smack_file_alloc_security(struct file *file)
{
struct smack_known *skp = smk_of_current();
file->f_security = skp;
return 0;
}
/**
* smack_file_free_security - clear a file security blob
* @file: the object
*
* The security blob for a file is a pointer to the master
* label list, so no memory is freed.
*/
static void smack_file_free_security(struct file *file)
{
file->f_security = NULL;
}
/**
* smack_file_ioctl - Smack check on ioctls
* @file: the object
* @cmd: what to do
* @arg: unused
*
* Relies heavily on the correct use of the ioctl command conventions.
*
* Returns 0 if allowed, error code otherwise
*/
static int smack_file_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int rc = 0;
struct smk_audit_info ad;
struct inode *inode = file_inode(file);
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
if (_IOC_DIR(cmd) & _IOC_WRITE) {
rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
rc = smk_bu_file(file, MAY_WRITE, rc);
}
if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
rc = smk_bu_file(file, MAY_READ, rc);
}
return rc;
}
/**
* smack_file_lock - Smack check on file locking
* @file: the object
* @cmd: unused
*
* Returns 0 if current has lock access, error code otherwise
*/
static int smack_file_lock(struct file *file, unsigned int cmd)
{
struct smk_audit_info ad;
int rc;
struct inode *inode = file_inode(file);
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
rc = smk_bu_file(file, MAY_LOCK, rc);
return rc;
}
/**
* smack_file_fcntl - Smack check on fcntl
* @file: the object
* @cmd: what action to check
* @arg: unused
*
* Generally these operations are harmless.
* File locking operations present an obvious mechanism
* for passing information, so they require write access.
*
* Returns 0 if current has access, error code otherwise
*/
static int smack_file_fcntl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct smk_audit_info ad;
int rc = 0;
struct inode *inode = file_inode(file);
switch (cmd) {
case F_GETLK:
break;
case F_SETLK:
case F_SETLKW:
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
rc = smk_bu_file(file, MAY_LOCK, rc);
break;
case F_SETOWN:
case F_SETSIG:
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
rc = smk_bu_file(file, MAY_WRITE, rc);
break;
default:
break;
}
return rc;
}
/**
* smack_mmap_file :
* Check permissions for a mmap operation. The @file may be NULL, e.g.
* if mapping anonymous memory.
* @file contains the file structure for file to map (may be NULL).
* @reqprot contains the protection requested by the application.
* @prot contains the protection that will be applied by the kernel.
* @flags contains the operational flags.
* Return 0 if permission is granted.
*/
static int smack_mmap_file(struct file *file,
unsigned long reqprot, unsigned long prot,
unsigned long flags)
{
struct smack_known *skp;
struct smack_known *mkp;
struct smack_rule *srp;
struct task_smack *tsp;
struct smack_known *okp;
struct inode_smack *isp;
int may;
int mmay;
int tmay;
int rc;
if (file == NULL)
return 0;
isp = file_inode(file)->i_security;
if (isp->smk_mmap == NULL)
return 0;
mkp = isp->smk_mmap;
tsp = current_security();
skp = smk_of_current();
rc = 0;
rcu_read_lock();
/*
* For each Smack rule associated with the subject
* label verify that the SMACK64MMAP also has access
* to that rule's object label.
*/
list_for_each_entry_rcu(srp, &skp->smk_rules, list) {
okp = srp->smk_object;
/*
* Matching labels always allows access.
*/
if (mkp->smk_known == okp->smk_known)
continue;
/*
* If there is a matching local rule take
* that into account as well.
*/
may = smk_access_entry(srp->smk_subject->smk_known,
okp->smk_known,
&tsp->smk_rules);
if (may == -ENOENT)
may = srp->smk_access;
else
may &= srp->smk_access;
/*
* If may is zero the SMACK64MMAP subject can't
* possibly have less access.
*/
if (may == 0)
continue;
/*
* Fetch the global list entry.
* If there isn't one a SMACK64MMAP subject
* can't have as much access as current.
*/
mmay = smk_access_entry(mkp->smk_known, okp->smk_known,
&mkp->smk_rules);
if (mmay == -ENOENT) {
rc = -EACCES;
break;
}
/*
* If there is a local entry it modifies the
* potential access, too.
*/
tmay = smk_access_entry(mkp->smk_known, okp->smk_known,
&tsp->smk_rules);
if (tmay != -ENOENT)
mmay &= tmay;
/*
* If there is any access available to current that is
* not available to a SMACK64MMAP subject
* deny access.
*/
if ((may | mmay) != mmay) {
rc = -EACCES;
break;
}
}
rcu_read_unlock();
return rc;
}
/**
* smack_file_set_fowner - set the file security blob value
* @file: object in question
*
*/
static void smack_file_set_fowner(struct file *file)
{
file->f_security = smk_of_current();
}
/**
* smack_file_send_sigiotask - Smack on sigio
* @tsk: The target task
* @fown: the object the signal come from
* @signum: unused
*
* Allow a privileged task to get signals even if it shouldn't
*
* Returns 0 if a subject with the object's smack could
* write to the task, an error code otherwise.
*/
static int smack_file_send_sigiotask(struct task_struct *tsk,
struct fown_struct *fown, int signum)
{
struct smack_known *skp;
struct smack_known *tkp = smk_of_task(tsk->cred->security);
struct file *file;
int rc;
struct smk_audit_info ad;
/*
* struct fown_struct is never outside the context of a struct file
*/
file = container_of(fown, struct file, f_owner);
/* we don't log here as rc can be overriden */
skp = file->f_security;
rc = smk_access(skp, tkp, MAY_WRITE, NULL);
rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc);
if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
rc = 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, tsk);
smack_log(skp->smk_known, tkp->smk_known, MAY_WRITE, rc, &ad);
return rc;
}
/**
* smack_file_receive - Smack file receive check
* @file: the object
*
* Returns 0 if current has access, error code otherwise
*/
static int smack_file_receive(struct file *file)
{
int rc;
int may = 0;
struct smk_audit_info ad;
struct inode *inode = file_inode(file);
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
/*
* This code relies on bitmasks.
*/
if (file->f_mode & FMODE_READ)
may = MAY_READ;
if (file->f_mode & FMODE_WRITE)
may |= MAY_WRITE;
rc = smk_curacc(smk_of_inode(inode), may, &ad);
rc = smk_bu_file(file, may, rc);
return rc;
}
/**
* smack_file_open - Smack dentry open processing
* @file: the object
* @cred: task credential
*
* Set the security blob in the file structure.
* Allow the open only if the task has read access. There are
* many read operations (e.g. fstat) that you can do with an
* fd even if you have the file open write-only.
*
* Returns 0
*/
static int smack_file_open(struct file *file, const struct cred *cred)
{
struct task_smack *tsp = cred->security;
struct inode *inode = file_inode(file);
struct smk_audit_info ad;
int rc;
if (smack_privileged(CAP_MAC_OVERRIDE))
return 0;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_access(tsp->smk_task, smk_of_inode(inode), MAY_READ, &ad);
rc = smk_bu_credfile(cred, file, MAY_READ, rc);
return rc;
}
/*
* Task hooks
*/
/**
* smack_cred_alloc_blank - "allocate" blank task-level security credentials
* @new: the new credentials
* @gfp: the atomicity of any memory allocations
*
* Prepare a blank set of credentials for modification. This must allocate all
* the memory the LSM module might require such that cred_transfer() can
* complete without error.
*/
static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
struct task_smack *tsp;
tsp = new_task_smack(NULL, NULL, gfp);
if (tsp == NULL)
return -ENOMEM;
cred->security = tsp;
return 0;
}
/**
* smack_cred_free - "free" task-level security credentials
* @cred: the credentials in question
*
*/
static void smack_cred_free(struct cred *cred)
{
struct task_smack *tsp = cred->security;
struct smack_rule *rp;
struct list_head *l;
struct list_head *n;
if (tsp == NULL)
return;
cred->security = NULL;
list_for_each_safe(l, n, &tsp->smk_rules) {
rp = list_entry(l, struct smack_rule, list);
list_del(&rp->list);
kfree(rp);
}
kfree(tsp);
}
/**
* smack_cred_prepare - prepare new set of credentials for modification
* @new: the new credentials
* @old: the original credentials
* @gfp: the atomicity of any memory allocations
*
* Prepare a new set of credentials for modification.
*/
static int smack_cred_prepare(struct cred *new, const struct cred *old,
gfp_t gfp)
{
struct task_smack *old_tsp = old->security;
struct task_smack *new_tsp;
int rc;
new_tsp = new_task_smack(old_tsp->smk_task, old_tsp->smk_task, gfp);
if (new_tsp == NULL)
return -ENOMEM;
rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp);
if (rc != 0)
return rc;
new->security = new_tsp;
return 0;
}
/**
* smack_cred_transfer - Transfer the old credentials to the new credentials
* @new: the new credentials
* @old: the original credentials
*
* Fill in a set of blank credentials from another set of credentials.
*/
static void smack_cred_transfer(struct cred *new, const struct cred *old)
{
struct task_smack *old_tsp = old->security;
struct task_smack *new_tsp = new->security;
new_tsp->smk_task = old_tsp->smk_task;
new_tsp->smk_forked = old_tsp->smk_task;
mutex_init(&new_tsp->smk_rules_lock);
INIT_LIST_HEAD(&new_tsp->smk_rules);
/* cbs copy rule list */
}
/**
* smack_kernel_act_as - Set the subjective context in a set of credentials
* @new: points to the set of credentials to be modified.
* @secid: specifies the security ID to be set
*
* Set the security data for a kernel service.
*/
static int smack_kernel_act_as(struct cred *new, u32 secid)
{
struct task_smack *new_tsp = new->security;
struct smack_known *skp = smack_from_secid(secid);
if (skp == NULL)
return -EINVAL;
new_tsp->smk_task = skp;
return 0;
}
/**
* smack_kernel_create_files_as - Set the file creation label in a set of creds
* @new: points to the set of credentials to be modified
* @inode: points to the inode to use as a reference
*
* Set the file creation context in a set of credentials to the same
* as the objective context of the specified inode
*/
static int smack_kernel_create_files_as(struct cred *new,
struct inode *inode)
{
struct inode_smack *isp = inode->i_security;
struct task_smack *tsp = new->security;
tsp->smk_forked = isp->smk_inode;
tsp->smk_task = tsp->smk_forked;
return 0;
}
/**
* smk_curacc_on_task - helper to log task related access
* @p: the task object
* @access: the access requested
* @caller: name of the calling function for audit
*
* Return 0 if access is permitted
*/
static int smk_curacc_on_task(struct task_struct *p, int access,
const char *caller)
{
struct smk_audit_info ad;
struct smack_known *skp = smk_of_task(task_security(p));
int rc;
smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
rc = smk_curacc(skp, access, &ad);
rc = smk_bu_task(p, access, rc);
return rc;
}
/**
* smack_task_setpgid - Smack check on setting pgid
* @p: the task object
* @pgid: unused
*
* Return 0 if write access is permitted
*/
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
return smk_curacc_on_task(p, MAY_WRITE, __func__);
}
/**
* smack_task_getpgid - Smack access check for getpgid
* @p: the object task
*
* Returns 0 if current can read the object task, error code otherwise
*/
static int smack_task_getpgid(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_getsid - Smack access check for getsid
* @p: the object task
*
* Returns 0 if current can read the object task, error code otherwise
*/
static int smack_task_getsid(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_getsecid - get the secid of the task
* @p: the object task
* @secid: where to put the result
*
* Sets the secid to contain a u32 version of the smack label.
*/
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
{
struct smack_known *skp = smk_of_task(task_security(p));
*secid = skp->smk_secid;
}
/**
* smack_task_setnice - Smack check on setting nice
* @p: the task object
* @nice: unused
*
* Return 0 if write access is permitted
*/
static int smack_task_setnice(struct task_struct *p, int nice)
{
int rc;
rc = cap_task_setnice(p, nice);
if (rc == 0)
rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
return rc;
}
/**
* smack_task_setioprio - Smack check on setting ioprio
* @p: the task object
* @ioprio: unused
*
* Return 0 if write access is permitted
*/
static int smack_task_setioprio(struct task_struct *p, int ioprio)
{
int rc;
rc = cap_task_setioprio(p, ioprio);
if (rc == 0)
rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
return rc;
}
/**
* smack_task_getioprio - Smack check on reading ioprio
* @p: the task object
*
* Return 0 if read access is permitted
*/
static int smack_task_getioprio(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_setscheduler - Smack check on setting scheduler
* @p: the task object
* @policy: unused
* @lp: unused
*
* Return 0 if read access is permitted
*/
static int smack_task_setscheduler(struct task_struct *p)
{
int rc;
rc = cap_task_setscheduler(p);
if (rc == 0)
rc = smk_curacc_on_task(p, MAY_WRITE, __func__);
return rc;
}
/**
* smack_task_getscheduler - Smack check on reading scheduler
* @p: the task object
*
* Return 0 if read access is permitted
*/
static int smack_task_getscheduler(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_READ, __func__);
}
/**
* smack_task_movememory - Smack check on moving memory
* @p: the task object
*
* Return 0 if write access is permitted
*/
static int smack_task_movememory(struct task_struct *p)
{
return smk_curacc_on_task(p, MAY_WRITE, __func__);
}
/**
* smack_task_kill - Smack check on signal delivery
* @p: the task object
* @info: unused
* @sig: unused
* @secid: identifies the smack to use in lieu of current's
*
* Return 0 if write access is permitted
*
* The secid behavior is an artifact of an SELinux hack
* in the USB code. Someday it may go away.
*/
static int smack_task_kill(struct task_struct *p, struct siginfo *info,
int sig, u32 secid)
{
struct smk_audit_info ad;
struct smack_known *skp;
struct smack_known *tkp = smk_of_task(task_security(p));
int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
/*
* Sending a signal requires that the sender
* can write the receiver.
*/
if (secid == 0) {
rc = smk_curacc(tkp, MAY_WRITE, &ad);
rc = smk_bu_task(p, MAY_WRITE, rc);
return rc;
}
/*
* If the secid isn't 0 we're dealing with some USB IO
* specific behavior. This is not clean. For one thing
* we can't take privilege into account.
*/
skp = smack_from_secid(secid);
rc = smk_access(skp, tkp, MAY_WRITE, &ad);
rc = smk_bu_note("USB signal", skp, tkp, MAY_WRITE, rc);
return rc;
}
/**
* smack_task_wait - Smack access check for waiting
* @p: task to wait for
*
* Returns 0
*/
static int smack_task_wait(struct task_struct *p)
{
/*
* Allow the operation to succeed.
* Zombies are bad.
* In userless environments (e.g. phones) programs
* get marked with SMACK64EXEC and even if the parent
* and child shouldn't be talking the parent still
* may expect to know when the child exits.
*/
return 0;
}
/**
* smack_task_to_inode - copy task smack into the inode blob
* @p: task to copy from
* @inode: inode to copy to
*
* Sets the smack pointer in the inode security blob
*/
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
struct inode_smack *isp = inode->i_security;
struct smack_known *skp = smk_of_task(task_security(p));
isp->smk_inode = skp;
}
/*
* Socket hooks.
*/
/**
* smack_sk_alloc_security - Allocate a socket blob
* @sk: the socket
* @family: unused
* @gfp_flags: memory allocation flags
*
* Assign Smack pointers to current
*
* Returns 0 on success, -ENOMEM is there's no memory
*/
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
{
struct smack_known *skp = smk_of_current();
struct socket_smack *ssp;
ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
if (ssp == NULL)
return -ENOMEM;
ssp->smk_in = skp;
ssp->smk_out = skp;
ssp->smk_packet = NULL;
sk->sk_security = ssp;
return 0;
}
/**
* smack_sk_free_security - Free a socket blob
* @sk: the socket
*
* Clears the blob pointer
*/
static void smack_sk_free_security(struct sock *sk)
{
kfree(sk->sk_security);
}
/**
* smack_host_label - check host based restrictions
* @sip: the object end
*
* looks for host based access restrictions
*
* This version will only be appropriate for really small sets of single label
* hosts. The caller is responsible for ensuring that the RCU read lock is
* taken before calling this function.
*
* Returns the label of the far end or NULL if it's not special.
*/
static struct smack_known *smack_host_label(struct sockaddr_in *sip)
{
struct smk_netlbladdr *snp;
struct in_addr *siap = &sip->sin_addr;
if (siap->s_addr == 0)
return NULL;
list_for_each_entry_rcu(snp, &smk_netlbladdr_list, list)
/*
* we break after finding the first match because
* the list is sorted from longest to shortest mask
* so we have found the most specific match
*/
if ((&snp->smk_host.sin_addr)->s_addr ==
(siap->s_addr & (&snp->smk_mask)->s_addr)) {
/* we have found the special CIPSO option */
if (snp->smk_label == &smack_cipso_option)
return NULL;
return snp->smk_label;
}
return NULL;
}
/**
* smack_netlabel - Set the secattr on a socket
* @sk: the socket
* @labeled: socket label scheme
*
* Convert the outbound smack value (smk_out) to a
* secattr and attach it to the socket.
*
* Returns 0 on success or an error code
*/
static int smack_netlabel(struct sock *sk, int labeled)
{
struct smack_known *skp;
struct socket_smack *ssp = sk->sk_security;
int rc = 0;
/*
* Usually the netlabel code will handle changing the
* packet labeling based on the label.
* The case of a single label host is different, because
* a single label host should never get a labeled packet
* even though the label is usually associated with a packet
* label.
*/
local_bh_disable();
bh_lock_sock_nested(sk);
if (ssp->smk_out == smack_net_ambient ||
labeled == SMACK_UNLABELED_SOCKET)
netlbl_sock_delattr(sk);
else {
skp = ssp->smk_out;
rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel);
}
bh_unlock_sock(sk);
local_bh_enable();
return rc;
}
/**
* smack_netlbel_send - Set the secattr on a socket and perform access checks
* @sk: the socket
* @sap: the destination address
*
* Set the correct secattr for the given socket based on the destination
* address and perform any outbound access checks needed.
*
* Returns 0 on success or an error code.
*
*/
static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
{
struct smack_known *skp;
int rc;
int sk_lbl;
struct smack_known *hkp;
struct socket_smack *ssp = sk->sk_security;
struct smk_audit_info ad;
rcu_read_lock();
hkp = smack_host_label(sap);
if (hkp != NULL) {
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
ad.a.u.net->family = sap->sin_family;
ad.a.u.net->dport = sap->sin_port;
ad.a.u.net->v4info.daddr = sap->sin_addr.s_addr;
#endif
sk_lbl = SMACK_UNLABELED_SOCKET;
skp = ssp->smk_out;
rc = smk_access(skp, hkp, MAY_WRITE, &ad);
rc = smk_bu_note("IPv4 host check", skp, hkp, MAY_WRITE, rc);
} else {
sk_lbl = SMACK_CIPSO_SOCKET;
rc = 0;
}
rcu_read_unlock();
if (rc != 0)
return rc;
return smack_netlabel(sk, sk_lbl);
}
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
/**
* smk_ipv6_port_label - Smack port access table management
* @sock: socket
* @address: address
*
* Create or update the port list entry
*/
static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
{
struct sock *sk = sock->sk;
struct sockaddr_in6 *addr6;
struct socket_smack *ssp = sock->sk->sk_security;
struct smk_port_label *spp;
unsigned short port = 0;
if (address == NULL) {
/*
* This operation is changing the Smack information
* on the bound socket. Take the changes to the port
* as well.
*/
list_for_each_entry(spp, &smk_ipv6_port_list, list) {
if (sk != spp->smk_sock)
continue;
spp->smk_in = ssp->smk_in;
spp->smk_out = ssp->smk_out;
return;
}
/*
* A NULL address is only used for updating existing
* bound entries. If there isn't one, it's OK.
*/
return;
}
addr6 = (struct sockaddr_in6 *)address;
port = ntohs(addr6->sin6_port);
/*
* This is a special case that is safely ignored.
*/
if (port == 0)
return;
/*
* Look for an existing port list entry.
* This is an indication that a port is getting reused.
*/
list_for_each_entry(spp, &smk_ipv6_port_list, list) {
if (spp->smk_port != port)
continue;
spp->smk_port = port;
spp->smk_sock = sk;
spp->smk_in = ssp->smk_in;
spp->smk_out = ssp->smk_out;
return;
}
/*
* A new port entry is required.
*/
spp = kzalloc(sizeof(*spp), GFP_KERNEL);
if (spp == NULL)
return;
spp->smk_port = port;
spp->smk_sock = sk;
spp->smk_in = ssp->smk_in;
spp->smk_out = ssp->smk_out;
list_add(&spp->list, &smk_ipv6_port_list);
return;
}
/**
* smk_ipv6_port_check - check Smack port access
* @sock: socket
* @address: address
*
* Create or update the port list entry
*/
static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
int act)
{
__be16 *bep;
__be32 *be32p;
struct smk_port_label *spp;
struct socket_smack *ssp = sk->sk_security;
struct smack_known *skp;
unsigned short port = 0;
struct smack_known *object;
struct smk_audit_info ad;
int rc;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
#endif
if (act == SMK_RECEIVING) {
skp = smack_net_ambient;
object = ssp->smk_in;
} else {
skp = ssp->smk_out;
object = smack_net_ambient;
}
/*
* Get the IP address and port from the address.
*/
port = ntohs(address->sin6_port);
bep = (__be16 *)(&address->sin6_addr);
be32p = (__be32 *)(&address->sin6_addr);
/*
* It's remote, so port lookup does no good.
*/
if (be32p[0] || be32p[1] || be32p[2] || bep[6] || ntohs(bep[7]) != 1)
goto auditout;
/*
* It's local so the send check has to have passed.
*/
if (act == SMK_RECEIVING) {
skp = &smack_known_web;
goto auditout;
}
list_for_each_entry(spp, &smk_ipv6_port_list, list) {
if (spp->smk_port != port)
continue;
object = spp->smk_in;
if (act == SMK_CONNECTING)
ssp->smk_packet = spp->smk_out;
break;
}
auditout:
#ifdef CONFIG_AUDIT
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
ad.a.u.net->family = sk->sk_family;
ad.a.u.net->dport = port;
if (act == SMK_RECEIVING)
ad.a.u.net->v6info.saddr = address->sin6_addr;
else
ad.a.u.net->v6info.daddr = address->sin6_addr;
#endif
rc = smk_access(skp, object, MAY_WRITE, &ad);
rc = smk_bu_note("IPv6 port check", skp, object, MAY_WRITE, rc);
return rc;
}
#endif /* CONFIG_IPV6 && !CONFIG_SECURITY_SMACK_NETFILTER */
/**
* smack_inode_setsecurity - set smack xattrs
* @inode: the object
* @name: attribute name
* @value: attribute value
* @size: size of the attribute
* @flags: unused
*
* Sets the named attribute in the appropriate blob
*
* Returns 0 on success, or an error code
*/
static int smack_inode_setsecurity(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
struct smack_known *skp;
struct inode_smack *nsp = inode->i_security;
struct socket_smack *ssp;
struct socket *sock;
int rc = 0;
if (value == NULL || size > SMK_LONGLABEL || size == 0)
return -EINVAL;
skp = smk_import_entry(value, size);
if (skp == NULL)
return -EINVAL;
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
nsp->smk_inode = skp;
nsp->smk_flags |= SMK_INODE_INSTANT;
return 0;
}
/*
* The rest of the Smack xattrs are only on sockets.
*/
if (inode->i_sb->s_magic != SOCKFS_MAGIC)
return -EOPNOTSUPP;
sock = SOCKET_I(inode);
if (sock == NULL || sock->sk == NULL)
return -EOPNOTSUPP;
ssp = sock->sk->sk_security;
if (strcmp(name, XATTR_SMACK_IPIN) == 0)
ssp->smk_in = skp;
else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
ssp->smk_out = skp;
if (sock->sk->sk_family == PF_INET) {
rc = smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
if (rc != 0)
printk(KERN_WARNING
"Smack: \"%s\" netlbl error %d.\n",
__func__, -rc);
}
} else
return -EOPNOTSUPP;
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
if (sock->sk->sk_family == PF_INET6)
smk_ipv6_port_label(sock, NULL);
#endif /* CONFIG_IPV6 && !CONFIG_SECURITY_SMACK_NETFILTER */
return 0;
}
/**
* smack_socket_post_create - finish socket setup
* @sock: the socket
* @family: protocol family
* @type: unused
* @protocol: unused
* @kern: unused
*
* Sets the netlabel information on the socket
*
* Returns 0 on success, and error code otherwise
*/
static int smack_socket_post_create(struct socket *sock, int family,
int type, int protocol, int kern)
{
if (family != PF_INET || sock->sk == NULL)
return 0;
/*
* Set the outbound netlbl.
*/
return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
}
#ifndef CONFIG_SECURITY_SMACK_NETFILTER
/**
* smack_socket_bind - record port binding information.
* @sock: the socket
* @address: the port address
* @addrlen: size of the address
*
* Records the label bound to a port.
*
* Returns 0
*/
static int smack_socket_bind(struct socket *sock, struct sockaddr *address,
int addrlen)
{
#if IS_ENABLED(CONFIG_IPV6)
if (sock->sk != NULL && sock->sk->sk_family == PF_INET6)
smk_ipv6_port_label(sock, address);
#endif
return 0;
}
#endif /* !CONFIG_SECURITY_SMACK_NETFILTER */
/**
* smack_socket_connect - connect access check
* @sock: the socket
* @sap: the other end
* @addrlen: size of sap
*
* Verifies that a connection may be possible
*
* Returns 0 on success, and error code otherwise
*/
static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
int addrlen)
{
int rc = 0;
if (sock->sk == NULL)
return 0;
switch (sock->sk->sk_family) {
case PF_INET:
if (addrlen < sizeof(struct sockaddr_in))
return -EINVAL;
rc = smack_netlabel_send(sock->sk, (struct sockaddr_in *)sap);
break;
case PF_INET6:
if (addrlen < sizeof(struct sockaddr_in6))
return -EINVAL;
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
rc = smk_ipv6_port_check(sock->sk, (struct sockaddr_in6 *)sap,
SMK_CONNECTING);
#endif /* CONFIG_IPV6 && !CONFIG_SECURITY_SMACK_NETFILTER */
break;
}
return rc;
}
/**
* smack_flags_to_may - convert S_ to MAY_ values
* @flags: the S_ value
*
* Returns the equivalent MAY_ value
*/
static int smack_flags_to_may(int flags)
{
int may = 0;
if (flags & S_IRUGO)
may |= MAY_READ;
if (flags & S_IWUGO)
may |= MAY_WRITE;
if (flags & S_IXUGO)
may |= MAY_EXEC;
return may;
}
/**
* smack_msg_msg_alloc_security - Set the security blob for msg_msg
* @msg: the object
*
* Returns 0
*/
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
{
struct smack_known *skp = smk_of_current();
msg->security = skp;
return 0;
}
/**
* smack_msg_msg_free_security - Clear the security blob for msg_msg
* @msg: the object
*
* Clears the blob pointer
*/
static void smack_msg_msg_free_security(struct msg_msg *msg)
{
msg->security = NULL;
}
/**
* smack_of_shm - the smack pointer for the shm
* @shp: the object
*
* Returns a pointer to the smack value
*/
static struct smack_known *smack_of_shm(struct shmid_kernel *shp)
{
return (struct smack_known *)shp->shm_perm.security;
}
/**
* smack_shm_alloc_security - Set the security blob for shm
* @shp: the object
*
* Returns 0
*/
static int smack_shm_alloc_security(struct shmid_kernel *shp)
{
struct kern_ipc_perm *isp = &shp->shm_perm;
struct smack_known *skp = smk_of_current();
isp->security = skp;
return 0;
}
/**
* smack_shm_free_security - Clear the security blob for shm
* @shp: the object
*
* Clears the blob pointer
*/
static void smack_shm_free_security(struct shmid_kernel *shp)
{
struct kern_ipc_perm *isp = &shp->shm_perm;
isp->security = NULL;
}
/**
* smk_curacc_shm : check if current has access on shm
* @shp : the object
* @access : access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smk_curacc_shm(struct shmid_kernel *shp, int access)
{
struct smack_known *ssp = smack_of_shm(shp);
struct smk_audit_info ad;
int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = shp->shm_perm.id;
#endif
rc = smk_curacc(ssp, access, &ad);
rc = smk_bu_current("shm", ssp, access, rc);
return rc;
}
/**
* smack_shm_associate - Smack access check for shm
* @shp: the object
* @shmflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_shm_associate(struct shmid_kernel *shp, int shmflg)
{
int may;
may = smack_flags_to_may(shmflg);
return smk_curacc_shm(shp, may);
}
/**
* smack_shm_shmctl - Smack access check for shm
* @shp: the object
* @cmd: what it wants to do
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd)
{
int may;
switch (cmd) {
case IPC_STAT:
case SHM_STAT:
may = MAY_READ;
break;
case IPC_SET:
case SHM_LOCK:
case SHM_UNLOCK:
case IPC_RMID:
may = MAY_READWRITE;
break;
case IPC_INFO:
case SHM_INFO:
/*
* System level information.
*/
return 0;
default:
return -EINVAL;
}
return smk_curacc_shm(shp, may);
}
/**
* smack_shm_shmat - Smack access for shmat
* @shp: the object
* @shmaddr: unused
* @shmflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
int shmflg)
{
int may;
may = smack_flags_to_may(shmflg);
return smk_curacc_shm(shp, may);
}
/**
* smack_of_sem - the smack pointer for the sem
* @sma: the object
*
* Returns a pointer to the smack value
*/
static struct smack_known *smack_of_sem(struct sem_array *sma)
{
return (struct smack_known *)sma->sem_perm.security;
}
/**
* smack_sem_alloc_security - Set the security blob for sem
* @sma: the object
*
* Returns 0
*/
static int smack_sem_alloc_security(struct sem_array *sma)
{
struct kern_ipc_perm *isp = &sma->sem_perm;
struct smack_known *skp = smk_of_current();
isp->security = skp;
return 0;
}
/**
* smack_sem_free_security - Clear the security blob for sem
* @sma: the object
*
* Clears the blob pointer
*/
static void smack_sem_free_security(struct sem_array *sma)
{
struct kern_ipc_perm *isp = &sma->sem_perm;
isp->security = NULL;
}
/**
* smk_curacc_sem : check if current has access on sem
* @sma : the object
* @access : access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smk_curacc_sem(struct sem_array *sma, int access)
{
struct smack_known *ssp = smack_of_sem(sma);
struct smk_audit_info ad;
int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = sma->sem_perm.id;
#endif
rc = smk_curacc(ssp, access, &ad);
rc = smk_bu_current("sem", ssp, access, rc);
return rc;
}
/**
* smack_sem_associate - Smack access check for sem
* @sma: the object
* @semflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_sem_associate(struct sem_array *sma, int semflg)
{
int may;
may = smack_flags_to_may(semflg);
return smk_curacc_sem(sma, may);
}
/**
* smack_sem_shmctl - Smack access check for sem
* @sma: the object
* @cmd: what it wants to do
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_sem_semctl(struct sem_array *sma, int cmd)
{
int may;
switch (cmd) {
case GETPID:
case GETNCNT:
case GETZCNT:
case GETVAL:
case GETALL:
case IPC_STAT:
case SEM_STAT:
may = MAY_READ;
break;
case SETVAL:
case SETALL:
case IPC_RMID:
case IPC_SET:
may = MAY_READWRITE;
break;
case IPC_INFO:
case SEM_INFO:
/*
* System level information
*/
return 0;
default:
return -EINVAL;
}
return smk_curacc_sem(sma, may);
}
/**
* smack_sem_semop - Smack checks of semaphore operations
* @sma: the object
* @sops: unused
* @nsops: unused
* @alter: unused
*
* Treated as read and write in all cases.
*
* Returns 0 if access is allowed, error code otherwise
*/
static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
unsigned nsops, int alter)
{
return smk_curacc_sem(sma, MAY_READWRITE);
}
/**
* smack_msg_alloc_security - Set the security blob for msg
* @msq: the object
*
* Returns 0
*/
static int smack_msg_queue_alloc_security(struct msg_queue *msq)
{
struct kern_ipc_perm *kisp = &msq->q_perm;
struct smack_known *skp = smk_of_current();
kisp->security = skp;
return 0;
}
/**
* smack_msg_free_security - Clear the security blob for msg
* @msq: the object
*
* Clears the blob pointer
*/
static void smack_msg_queue_free_security(struct msg_queue *msq)
{
struct kern_ipc_perm *kisp = &msq->q_perm;
kisp->security = NULL;
}
/**
* smack_of_msq - the smack pointer for the msq
* @msq: the object
*
* Returns a pointer to the smack label entry
*/
static struct smack_known *smack_of_msq(struct msg_queue *msq)
{
return (struct smack_known *)msq->q_perm.security;
}
/**
* smk_curacc_msq : helper to check if current has access on msq
* @msq : the msq
* @access : access requested
*
* return 0 if current has access, error otherwise
*/
static int smk_curacc_msq(struct msg_queue *msq, int access)
{
struct smack_known *msp = smack_of_msq(msq);
struct smk_audit_info ad;
int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = msq->q_perm.id;
#endif
rc = smk_curacc(msp, access, &ad);
rc = smk_bu_current("msq", msp, access, rc);
return rc;
}
/**
* smack_msg_queue_associate - Smack access check for msg_queue
* @msq: the object
* @msqflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg)
{
int may;
may = smack_flags_to_may(msqflg);
return smk_curacc_msq(msq, may);
}
/**
* smack_msg_queue_msgctl - Smack access check for msg_queue
* @msq: the object
* @cmd: what it wants to do
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
{
int may;
switch (cmd) {
case IPC_STAT:
case MSG_STAT:
may = MAY_READ;
break;
case IPC_SET:
case IPC_RMID:
may = MAY_READWRITE;
break;
case IPC_INFO:
case MSG_INFO:
/*
* System level information
*/
return 0;
default:
return -EINVAL;
}
return smk_curacc_msq(msq, may);
}
/**
* smack_msg_queue_msgsnd - Smack access check for msg_queue
* @msq: the object
* @msg: unused
* @msqflg: access requested
*
* Returns 0 if current has the requested access, error code otherwise
*/
static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg,
int msqflg)
{
int may;
may = smack_flags_to_may(msqflg);
return smk_curacc_msq(msq, may);
}
/**
* smack_msg_queue_msgsnd - Smack access check for msg_queue
* @msq: the object
* @msg: unused
* @target: unused
* @type: unused
* @mode: unused
*
* Returns 0 if current has read and write access, error code otherwise
*/
static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
struct task_struct *target, long type, int mode)
{
return smk_curacc_msq(msq, MAY_READWRITE);
}
/**
* smack_ipc_permission - Smack access for ipc_permission()
* @ipp: the object permissions
* @flag: access requested
*
* Returns 0 if current has read and write access, error code otherwise
*/
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
{
struct smack_known *iskp = ipp->security;
int may = smack_flags_to_may(flag);
struct smk_audit_info ad;
int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = ipp->id;
#endif
rc = smk_curacc(iskp, may, &ad);
rc = smk_bu_current("svipc", iskp, may, rc);
return rc;
}
/**
* smack_ipc_getsecid - Extract smack security id
* @ipp: the object permissions
* @secid: where result will be saved
*/
static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
{
struct smack_known *iskp = ipp->security;
*secid = iskp->smk_secid;
}
/**
* smack_d_instantiate - Make sure the blob is correct on an inode
* @opt_dentry: dentry where inode will be attached
* @inode: the object
*
* Set the inode's security blob if it hasn't been done already.
*/
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
{
struct super_block *sbp;
struct superblock_smack *sbsp;
struct inode_smack *isp;
struct smack_known *skp;
struct smack_known *ckp = smk_of_current();
struct smack_known *final;
char trattr[TRANS_TRUE_SIZE];
int transflag = 0;
int rc;
struct dentry *dp;
if (inode == NULL)
return;
isp = inode->i_security;
mutex_lock(&isp->smk_lock);
/*
* If the inode is already instantiated
* take the quick way out
*/
if (isp->smk_flags & SMK_INODE_INSTANT)
goto unlockandout;
sbp = inode->i_sb;
sbsp = sbp->s_security;
/*
* We're going to use the superblock default label
* if there's no label on the file.
*/
final = sbsp->smk_default;
/*
* If this is the root inode the superblock
* may be in the process of initialization.
* If that is the case use the root value out
* of the superblock.
*/
if (opt_dentry->d_parent == opt_dentry) {
switch (sbp->s_magic) {
case CGROUP_SUPER_MAGIC:
/*
* The cgroup filesystem is never mounted,
* so there's no opportunity to set the mount
* options.
*/
sbsp->smk_root = &smack_known_star;
sbsp->smk_default = &smack_known_star;
isp->smk_inode = sbsp->smk_root;
break;
case TMPFS_MAGIC:
/*
* What about shmem/tmpfs anonymous files with dentry
* obtained from d_alloc_pseudo()?
*/
isp->smk_inode = smk_of_current();
break;
default:
isp->smk_inode = sbsp->smk_root;
break;
}
isp->smk_flags |= SMK_INODE_INSTANT;
goto unlockandout;
}
/*
* This is pretty hackish.
* Casey says that we shouldn't have to do
* file system specific code, but it does help
* with keeping it simple.
*/
switch (sbp->s_magic) {
case SMACK_MAGIC:
case PIPEFS_MAGIC:
case SOCKFS_MAGIC:
case CGROUP_SUPER_MAGIC:
/*
* Casey says that it's a little embarrassing
* that the smack file system doesn't do
* extended attributes.
*
* Casey says pipes are easy (?)
*
* Socket access is controlled by the socket
* structures associated with the task involved.
*
* Cgroupfs is special
*/
final = &smack_known_star;
break;
case DEVPTS_SUPER_MAGIC:
/*
* devpts seems content with the label of the task.
* Programs that change smack have to treat the
* pty with respect.
*/
final = ckp;
break;
case PROC_SUPER_MAGIC:
/*
* Casey says procfs appears not to care.
* The superblock default suffices.
*/
break;
case TMPFS_MAGIC:
/*
* Device labels should come from the filesystem,
* but watch out, because they're volitile,
* getting recreated on every reboot.
*/
final = &smack_known_star;
/*
* No break.
*
* If a smack value has been set we want to use it,
* but since tmpfs isn't giving us the opportunity
* to set mount options simulate setting the
* superblock default.
*/
default:
/*
* This isn't an understood special case.
* Get the value from the xattr.
*/
/*
* UNIX domain sockets use lower level socket data.
*/
if (S_ISSOCK(inode->i_mode)) {
final = &smack_known_star;
break;
}
/*
* No xattr support means, alas, no SMACK label.
* Use the aforeapplied default.
* It would be curious if the label of the task
* does not match that assigned.
*/
if (inode->i_op->getxattr == NULL)
break;
/*
* Get the dentry for xattr.
*/
dp = dget(opt_dentry);
skp = smk_fetch(XATTR_NAME_SMACK, inode, dp);
if (skp != NULL)
final = skp;
/*
* Transmuting directory
*/
if (S_ISDIR(inode->i_mode)) {
/*
* If this is a new directory and the label was
* transmuted when the inode was initialized
* set the transmute attribute on the directory
* and mark the inode.
*
* If there is a transmute attribute on the
* directory mark the inode.
*/
if (isp->smk_flags & SMK_INODE_CHANGED) {
isp->smk_flags &= ~SMK_INODE_CHANGED;
rc = inode->i_op->setxattr(dp,
XATTR_NAME_SMACKTRANSMUTE,
TRANS_TRUE, TRANS_TRUE_SIZE,
0);
} else {
rc = inode->i_op->getxattr(dp,
XATTR_NAME_SMACKTRANSMUTE, trattr,
TRANS_TRUE_SIZE);
if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
TRANS_TRUE_SIZE) != 0)
rc = -EINVAL;
}
if (rc >= 0)
transflag = SMK_INODE_TRANSMUTE;
}
/*
* Don't let the exec or mmap label be "*" or "@".
*/
skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
if (skp == &smack_known_star || skp == &smack_known_web)
skp = NULL;
isp->smk_task = skp;
skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
if (skp == &smack_known_star || skp == &smack_known_web)
skp = NULL;
isp->smk_mmap = skp;
dput(dp);
break;
}
if (final == NULL)
isp->smk_inode = ckp;
else
isp->smk_inode = final;
isp->smk_flags |= (SMK_INODE_INSTANT | transflag);
unlockandout:
mutex_unlock(&isp->smk_lock);
return;
}
/**
* smack_getprocattr - Smack process attribute access
* @p: the object task
* @name: the name of the attribute in /proc/.../attr
* @value: where to put the result
*
* Places a copy of the task Smack into value
*
* Returns the length of the smack label or an error code
*/
static int smack_getprocattr(struct task_struct *p, char *name, char **value)
{
struct smack_known *skp = smk_of_task(task_security(p));
char *cp;
int slen;
if (strcmp(name, "current") != 0)
return -EINVAL;
cp = kstrdup(skp->smk_known, GFP_KERNEL);
if (cp == NULL)
return -ENOMEM;
slen = strlen(cp);
*value = cp;
return slen;
}
/**
* smack_setprocattr - Smack process attribute setting
* @p: the object task
* @name: the name of the attribute in /proc/.../attr
* @value: the value to set
* @size: the size of the value
*
* Sets the Smack value of the task. Only setting self
* is permitted and only with privilege
*
* Returns the length of the smack label or an error code
*/
static int smack_setprocattr(struct task_struct *p, char *name,
void *value, size_t size)
{
struct task_smack *tsp;
struct cred *new;
struct smack_known *skp;
/*
* Changing another process' Smack value is too dangerous
* and supports no sane use case.
*/
if (p != current)
return -EPERM;
if (!smack_privileged(CAP_MAC_ADMIN))
return -EPERM;
if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
return -EINVAL;
if (strcmp(name, "current") != 0)
return -EINVAL;
skp = smk_import_entry(value, size);
if (skp == NULL)
return -EINVAL;
/*
* No process is ever allowed the web ("@") label.
*/
if (skp == &smack_known_web)
return -EPERM;
new = prepare_creds();
if (new == NULL)
return -ENOMEM;
tsp = new->security;
tsp->smk_task = skp;
commit_creds(new);
return size;
}
/**
* smack_unix_stream_connect - Smack access on UDS
* @sock: one sock
* @other: the other sock
* @newsk: unused
*
* Return 0 if a subject with the smack of sock could access
* an object with the smack of other, otherwise an error code
*/
static int smack_unix_stream_connect(struct sock *sock,
struct sock *other, struct sock *newsk)
{
struct smack_known *skp;
struct smack_known *okp;
struct socket_smack *ssp = sock->sk_security;
struct socket_smack *osp = other->sk_security;
struct socket_smack *nsp = newsk->sk_security;
struct smk_audit_info ad;
int rc = 0;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
#endif
if (!smack_privileged(CAP_MAC_OVERRIDE)) {
skp = ssp->smk_out;
okp = osp->smk_in;
#ifdef CONFIG_AUDIT
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
smk_ad_setfield_u_net_sk(&ad, other);
#endif
rc = smk_access(skp, okp, MAY_WRITE, &ad);
rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
if (rc == 0) {
okp = osp->smk_out;
skp = ssp->smk_in;
rc = smk_access(okp, skp, MAY_WRITE, NULL);
rc = smk_bu_note("UDS connect", okp, skp,
MAY_WRITE, rc);
}
}
/*
* Cross reference the peer labels for SO_PEERSEC.
*/
if (rc == 0) {
nsp->smk_packet = ssp->smk_out;
ssp->smk_packet = osp->smk_out;
}
return rc;
}
/**
* smack_unix_may_send - Smack access on UDS
* @sock: one socket
* @other: the other socket
*
* Return 0 if a subject with the smack of sock could access
* an object with the smack of other, otherwise an error code
*/
static int smack_unix_may_send(struct socket *sock, struct socket *other)
{
struct socket_smack *ssp = sock->sk->sk_security;
struct socket_smack *osp = other->sk->sk_security;
struct smk_audit_info ad;
int rc;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
smk_ad_setfield_u_net_sk(&ad, other->sk);
#endif
if (smack_privileged(CAP_MAC_OVERRIDE))
return 0;
rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
rc = smk_bu_note("UDS send", ssp->smk_out, osp->smk_in, MAY_WRITE, rc);
return rc;
}
/**
* smack_socket_sendmsg - Smack check based on destination host
* @sock: the socket
* @msg: the message
* @size: the size of the message
*
* Return 0 if the current subject can write to the destination host.
* For IPv4 this is only a question if the destination is a single label host.
* For IPv6 this is a check against the label of the port.
*/
static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
int size)
{
struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
#endif /* CONFIG_IPV6 && !CONFIG_SECURITY_SMACK_NETFILTER */
int rc = 0;
/*
* Perfectly reasonable for this to be NULL
*/
if (sip == NULL)
return 0;
switch (sip->sin_family) {
case AF_INET:
rc = smack_netlabel_send(sock->sk, sip);
break;
case AF_INET6:
#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
rc = smk_ipv6_port_check(sock->sk, sap, SMK_SENDING);
#endif /* CONFIG_IPV6 && !CONFIG_SECURITY_SMACK_NETFILTER */
break;
}
return rc;
}
/**
* smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
* @sap: netlabel secattr
* @ssp: socket security information
*
* Returns a pointer to a Smack label entry found on the label list.
*/
static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
struct socket_smack *ssp)
{
struct smack_known *skp;
int found = 0;
int acat;
int kcat;
if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
/*
* Looks like a CIPSO packet.
* If there are flags but no level netlabel isn't
* behaving the way we expect it to.
*
* Look it up in the label table
* Without guidance regarding the smack value
* for the packet fall back on the network
* ambient value.
*/
rcu_read_lock();
list_for_each_entry(skp, &smack_known_list, list) {
if (sap->attr.mls.lvl != skp->smk_netlabel.attr.mls.lvl)
continue;
/*
* Compare the catsets. Use the netlbl APIs.
*/
if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) {
if ((skp->smk_netlabel.flags &
NETLBL_SECATTR_MLS_CAT) == 0)
found = 1;
break;
}
for (acat = -1, kcat = -1; acat == kcat; ) {
acat = netlbl_catmap_walk(sap->attr.mls.cat,
acat + 1);
kcat = netlbl_catmap_walk(
skp->smk_netlabel.attr.mls.cat,
kcat + 1);
if (acat < 0 || kcat < 0)
break;
}
if (acat == kcat) {
found = 1;
break;
}
}
rcu_read_unlock();
if (found)
return skp;
if (ssp != NULL && ssp->smk_in == &smack_known_star)
return &smack_known_web;
return &smack_known_star;
}
if ((sap->flags & NETLBL_SECATTR_SECID) != 0) {
/*
* Looks like a fallback, which gives us a secid.
*/
skp = smack_from_secid(sap->attr.secid);
/*
* This has got to be a bug because it is
* impossible to specify a fallback without
* specifying the label, which will ensure
* it has a secid, and the only way to get a
* secid is from a fallback.
*/
BUG_ON(skp == NULL);
return skp;
}
/*
* Without guidance regarding the smack value
* for the packet fall back on the network
* ambient value.
*/
return smack_net_ambient;
}
#if IS_ENABLED(CONFIG_IPV6)
static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
{
u8 nexthdr;
int offset;
int proto = -EINVAL;
struct ipv6hdr _ipv6h;
struct ipv6hdr *ip6;
__be16 frag_off;
struct tcphdr _tcph, *th;
struct udphdr _udph, *uh;
struct dccp_hdr _dccph, *dh;
sip->sin6_port = 0;
offset = skb_network_offset(skb);
ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
if (ip6 == NULL)
return -EINVAL;
sip->sin6_addr = ip6->saddr;
nexthdr = ip6->nexthdr;
offset += sizeof(_ipv6h);
offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
if (offset < 0)
return -EINVAL;
proto = nexthdr;
switch (proto) {
case IPPROTO_TCP:
th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
if (th != NULL)
sip->sin6_port = th->source;
break;
case IPPROTO_UDP:
uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
if (uh != NULL)
sip->sin6_port = uh->source;
break;
case IPPROTO_DCCP:
dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
if (dh != NULL)
sip->sin6_port = dh->dccph_sport;
break;
}
return proto;
}
#endif /* CONFIG_IPV6 */
/**
* smack_socket_sock_rcv_skb - Smack packet delivery access check
* @sk: socket
* @skb: packet
*
* Returns 0 if the packet should be delivered, an error code otherwise
*/
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
struct netlbl_lsm_secattr secattr;
struct socket_smack *ssp = sk->sk_security;
struct smack_known *skp = NULL;
int rc = 0;
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
#endif
#if IS_ENABLED(CONFIG_IPV6)
struct sockaddr_in6 sadd;
int proto;
#endif /* CONFIG_IPV6 */
switch (sk->sk_family) {
case PF_INET:
#ifdef CONFIG_SECURITY_SMACK_NETFILTER
/*
* If there is a secmark use it rather than the CIPSO label.
* If there is no secmark fall back to CIPSO.
* The secmark is assumed to reflect policy better.
*/
if (skb && skb->secmark != 0) {
skp = smack_from_secid(skb->secmark);
goto access_check;
}
#endif /* CONFIG_SECURITY_SMACK_NETFILTER */
/*
* Translate what netlabel gave us.
*/
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr);
if (rc == 0)
skp = smack_from_secattr(&secattr, ssp);
else
skp = smack_net_ambient;
netlbl_secattr_destroy(&secattr);
#ifdef CONFIG_SECURITY_SMACK_NETFILTER
access_check:
#endif
#ifdef CONFIG_AUDIT
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
ad.a.u.net->family = sk->sk_family;
ad.a.u.net->netif = skb->skb_iif;
ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
/*
* Receiving a packet requires that the other end
* be able to write here. Read access is not required.
* This is the simplist possible security model
* for networking.
*/
rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
MAY_WRITE, rc);
if (rc != 0)
netlbl_skbuff_err(skb, rc, 0);
break;
#if IS_ENABLED(CONFIG_IPV6)
case PF_INET6:
proto = smk_skb_to_addr_ipv6(skb, &sadd);
if (proto != IPPROTO_UDP && proto != IPPROTO_TCP)
break;
#ifdef CONFIG_SECURITY_SMACK_NETFILTER
if (skb && skb->secmark != 0)
skp = smack_from_secid(skb->secmark);
else
skp = smack_net_ambient;
#ifdef CONFIG_AUDIT
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
ad.a.u.net->family = sk->sk_family;
ad.a.u.net->netif = skb->skb_iif;
ipv6_skb_to_auditdata(skb, &ad.a, NULL);
#endif /* CONFIG_AUDIT */
rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
rc = smk_bu_note("IPv6 delivery", skp, ssp->smk_in,
MAY_WRITE, rc);
#else /* CONFIG_SECURITY_SMACK_NETFILTER */
rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING);
#endif /* CONFIG_SECURITY_SMACK_NETFILTER */
break;
#endif /* CONFIG_IPV6 */
}
return rc;
}
/**
* smack_socket_getpeersec_stream - pull in packet label
* @sock: the socket
* @optval: user's destination
* @optlen: size thereof
* @len: max thereof
*
* returns zero on success, an error code otherwise
*/
static int smack_socket_getpeersec_stream(struct socket *sock,
char __user *optval,
int __user *optlen, unsigned len)
{
struct socket_smack *ssp;
char *rcp = "";
int slen = 1;
int rc = 0;
ssp = sock->sk->sk_security;
if (ssp->smk_packet != NULL) {
rcp = ssp->smk_packet->smk_known;
slen = strlen(rcp) + 1;
}
if (slen > len)
rc = -ERANGE;
else if (copy_to_user(optval, rcp, slen) != 0)
rc = -EFAULT;
if (put_user(slen, optlen) != 0)
rc = -EFAULT;
return rc;
}
/**
* smack_socket_getpeersec_dgram - pull in packet label
* @sock: the peer socket
* @skb: packet data
* @secid: pointer to where to put the secid of the packet
*
* Sets the netlabel socket state on sk from parent
*/
static int smack_socket_getpeersec_dgram(struct socket *sock,
struct sk_buff *skb, u32 *secid)
{
struct netlbl_lsm_secattr secattr;
struct socket_smack *ssp = NULL;
struct smack_known *skp;
int family = PF_UNSPEC;
u32 s = 0; /* 0 is the invalid secid */
int rc;
if (skb != NULL) {
if (skb->protocol == htons(ETH_P_IP))
family = PF_INET;
#if IS_ENABLED(CONFIG_IPV6)
else if (skb->protocol == htons(ETH_P_IPV6))
family = PF_INET6;
#endif /* CONFIG_IPV6 */
}
if (family == PF_UNSPEC && sock != NULL)
family = sock->sk->sk_family;
switch (family) {
case PF_UNIX:
ssp = sock->sk->sk_security;
s = ssp->smk_out->smk_secid;
break;
case PF_INET:
#ifdef CONFIG_SECURITY_SMACK_NETFILTER
s = skb->secmark;
if (s != 0)
break;
#endif
/*
* Translate what netlabel gave us.
*/
if (sock != NULL && sock->sk != NULL)
ssp = sock->sk->sk_security;
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0) {
skp = smack_from_secattr(&secattr, ssp);
s = skp->smk_secid;
}
netlbl_secattr_destroy(&secattr);
break;
#if IS_ENABLED(CONFIG_IPV6)
case PF_INET6:
#ifdef CONFIG_SECURITY_SMACK_NETFILTER
s = skb->secmark;
#endif /* CONFIG_SECURITY_SMACK_NETFILTER */
break;
#endif /* CONFIG_IPV6 */
}
*secid = s;
if (s == 0)
return -EINVAL;
return 0;
}
/**
* smack_sock_graft - Initialize a newly created socket with an existing sock
* @sk: child sock
* @parent: parent socket
*
* Set the smk_{in,out} state of an existing sock based on the process that
* is creating the new socket.
*/
static void smack_sock_graft(struct sock *sk, struct socket *parent)
{
struct socket_smack *ssp;
struct smack_known *skp = smk_of_current();
if (sk == NULL ||
(sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
return;
ssp = sk->sk_security;
ssp->smk_in = skp;
ssp->smk_out = skp;
/* cssp->smk_packet is already set in smack_inet_csk_clone() */
}
/**
* smack_inet_conn_request - Smack access check on connect
* @sk: socket involved
* @skb: packet
* @req: unused
*
* Returns 0 if a task with the packet label could write to
* the socket, otherwise an error code
*/
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
u16 family = sk->sk_family;
struct smack_known *skp;
struct socket_smack *ssp = sk->sk_security;
struct netlbl_lsm_secattr secattr;
struct sockaddr_in addr;
struct iphdr *hdr;
struct smack_known *hskp;
int rc;
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
#endif
#if IS_ENABLED(CONFIG_IPV6)
if (family == PF_INET6) {
/*
* Handle mapped IPv4 packets arriving
* via IPv6 sockets. Don't set up netlabel
* processing on IPv6.
*/
if (skb->protocol == htons(ETH_P_IP))
family = PF_INET;
else
return 0;
}
#endif /* CONFIG_IPV6 */
netlbl_secattr_init(&secattr);
rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0)
skp = smack_from_secattr(&secattr, ssp);
else
skp = &smack_known_huh;
netlbl_secattr_destroy(&secattr);
#ifdef CONFIG_AUDIT
smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
ad.a.u.net->family = family;
ad.a.u.net->netif = skb->skb_iif;
ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
/*
* Receiving a packet requires that the other end be able to write
* here. Read access is not required.
*/
rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in, MAY_WRITE, rc);
if (rc != 0)
return rc;
/*
* Save the peer's label in the request_sock so we can later setup
* smk_packet in the child socket so that SO_PEERCRED can report it.
*/
req->peer_secid = skp->smk_secid;
/*
* We need to decide if we want to label the incoming connection here
* if we do we only need to label the request_sock and the stack will
* propagate the wire-label to the sock when it is created.
*/
hdr = ip_hdr(skb);
addr.sin_addr.s_addr = hdr->saddr;
rcu_read_lock();
hskp = smack_host_label(&addr);
rcu_read_unlock();
if (hskp == NULL)
rc = netlbl_req_setattr(req, &skp->smk_netlabel);
else
netlbl_req_delattr(req);
return rc;
}
/**
* smack_inet_csk_clone - Copy the connection information to the new socket
* @sk: the new socket
* @req: the connection's request_sock
*
* Transfer the connection's peer label to the newly created socket.
*/
static void smack_inet_csk_clone(struct sock *sk,
const struct request_sock *req)
{
struct socket_smack *ssp = sk->sk_security;
struct smack_known *skp;
if (req->peer_secid != 0) {
skp = smack_from_secid(req->peer_secid);
ssp->smk_packet = skp;
} else
ssp->smk_packet = NULL;
}
/*
* Key management security hooks
*
* Casey has not tested key support very heavily.
* The permission check is most likely too restrictive.
* If you care about keys please have a look.
*/
#ifdef CONFIG_KEYS
/**
* smack_key_alloc - Set the key security blob
* @key: object
* @cred: the credentials to use
* @flags: unused
*
* No allocation required
*
* Returns 0
*/
static int smack_key_alloc(struct key *key, const struct cred *cred,
unsigned long flags)
{
struct smack_known *skp = smk_of_task(cred->security);
key->security = skp;
return 0;
}
/**
* smack_key_free - Clear the key security blob
* @key: the object
*
* Clear the blob pointer
*/
static void smack_key_free(struct key *key)
{
key->security = NULL;
}
/**
* smack_key_permission - Smack access on a key
* @key_ref: gets to the object
* @cred: the credentials to use
* @perm: requested key permissions
*
* Return 0 if the task has read and write to the object,
* an error code otherwise
*/
static int smack_key_permission(key_ref_t key_ref,
const struct cred *cred, unsigned perm)
{
struct key *keyp;
struct smk_audit_info ad;
struct smack_known *tkp = smk_of_task(cred->security);
int request = 0;
int rc;
keyp = key_ref_to_ptr(key_ref);
if (keyp == NULL)
return -EINVAL;
/*
* If the key hasn't been initialized give it access so that
* it may do so.
*/
if (keyp->security == NULL)
return 0;
/*
* This should not occur
*/
if (tkp == NULL)
return -EACCES;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
ad.a.u.key_struct.key = keyp->serial;
ad.a.u.key_struct.key_desc = keyp->description;
#endif
if (perm & KEY_NEED_READ)
request = MAY_READ;
if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
request = MAY_WRITE;
rc = smk_access(tkp, keyp->security, request, &ad);
rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
return rc;
}
#endif /* CONFIG_KEYS */
/*
* Smack Audit hooks
*
* Audit requires a unique representation of each Smack specific
* rule. This unique representation is used to distinguish the
* object to be audited from remaining kernel objects and also
* works as a glue between the audit hooks.
*
* Since repository entries are added but never deleted, we'll use
* the smack_known label address related to the given audit rule as
* the needed unique representation. This also better fits the smack
* model where nearly everything is a label.
*/
#ifdef CONFIG_AUDIT
/**
* smack_audit_rule_init - Initialize a smack audit rule
* @field: audit rule fields given from user-space (audit.h)
* @op: required testing operator (=, !=, >, <, ...)
* @rulestr: smack label to be audited
* @vrule: pointer to save our own audit rule representation
*
* Prepare to audit cases where (@field @op @rulestr) is true.
* The label to be audited is created if necessay.
*/
static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
struct smack_known *skp;
char **rule = (char **)vrule;
*rule = NULL;
if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
return -EINVAL;
if (op != Audit_equal && op != Audit_not_equal)
return -EINVAL;
skp = smk_import_entry(rulestr, 0);
if (skp)
*rule = skp->smk_known;
return 0;
}
/**
* smack_audit_rule_known - Distinguish Smack audit rules
* @krule: rule of interest, in Audit kernel representation format
*
* This is used to filter Smack rules from remaining Audit ones.
* If it's proved that this rule belongs to us, the
* audit_rule_match hook will be called to do the final judgement.
*/
static int smack_audit_rule_known(struct audit_krule *krule)
{
struct audit_field *f;
int i;
for (i = 0; i < krule->field_count; i++) {
f = &krule->fields[i];
if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
return 1;
}
return 0;
}
/**
* smack_audit_rule_match - Audit given object ?
* @secid: security id for identifying the object to test
* @field: audit rule flags given from user-space
* @op: required testing operator
* @vrule: smack internal rule presentation
* @actx: audit context associated with the check
*
* The core Audit hook. It's used to take the decision of
* whether to audit or not to audit a given object.
*/
static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
struct audit_context *actx)
{
struct smack_known *skp;
char *rule = vrule;
if (unlikely(!rule)) {
WARN_ONCE(1, "Smack: missing rule\n");
return -ENOENT;
}
if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
return 0;
skp = smack_from_secid(secid);
/*
* No need to do string comparisons. If a match occurs,
* both pointers will point to the same smack_known
* label.
*/
if (op == Audit_equal)
return (rule == skp->smk_known);
if (op == Audit_not_equal)
return (rule != skp->smk_known);
return 0;
}
/**
* smack_audit_rule_free - free smack rule representation
* @vrule: rule to be freed.
*
* No memory was allocated.
*/
static void smack_audit_rule_free(void *vrule)
{
/* No-op */
}
#endif /* CONFIG_AUDIT */
/**
* smack_ismaclabel - check if xattr @name references a smack MAC label
* @name: Full xattr name to check.
*/
static int smack_ismaclabel(const char *name)
{
return (strcmp(name, XATTR_SMACK_SUFFIX) == 0);
}
/**
* smack_secid_to_secctx - return the smack label for a secid
* @secid: incoming integer
* @secdata: destination
* @seclen: how long it is
*
* Exists for networking code.
*/
static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
struct smack_known *skp = smack_from_secid(secid);
if (secdata)
*secdata = skp->smk_known;
*seclen = strlen(skp->smk_known);
return 0;
}
/**
* smack_secctx_to_secid - return the secid for a smack label
* @secdata: smack label
* @seclen: how long result is
* @secid: outgoing integer
*
* Exists for audit and networking code.
*/
static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
struct smack_known *skp = smk_find_entry(secdata);
if (skp)
*secid = skp->smk_secid;
else
*secid = 0;
return 0;
}
/**
* smack_release_secctx - don't do anything.
* @secdata: unused
* @seclen: unused
*
* Exists to make sure nothing gets done, and properly
*/
static void smack_release_secctx(char *secdata, u32 seclen)
{
}
static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
{
return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx, ctxlen, 0);
}
static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
{
return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0);
}
static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
{
int len = 0;
len = smack_inode_getsecurity(inode, XATTR_SMACK_SUFFIX, ctx, true);
if (len < 0)
return len;
*ctxlen = len;
return 0;
}
struct security_operations smack_ops = {
.name = "smack",
.ptrace_access_check = smack_ptrace_access_check,
.ptrace_traceme = smack_ptrace_traceme,
.syslog = smack_syslog,
.sb_alloc_security = smack_sb_alloc_security,
.sb_free_security = smack_sb_free_security,
.sb_copy_data = smack_sb_copy_data,
.sb_kern_mount = smack_sb_kern_mount,
.sb_statfs = smack_sb_statfs,
.bprm_set_creds = smack_bprm_set_creds,
.bprm_committing_creds = smack_bprm_committing_creds,
.bprm_secureexec = smack_bprm_secureexec,
.inode_alloc_security = smack_inode_alloc_security,
.inode_free_security = smack_inode_free_security,
.inode_init_security = smack_inode_init_security,
.inode_link = smack_inode_link,
.inode_unlink = smack_inode_unlink,
.inode_rmdir = smack_inode_rmdir,
.inode_rename = smack_inode_rename,
.inode_permission = smack_inode_permission,
.inode_setattr = smack_inode_setattr,
.inode_getattr = smack_inode_getattr,
.inode_setxattr = smack_inode_setxattr,
.inode_post_setxattr = smack_inode_post_setxattr,
.inode_getxattr = smack_inode_getxattr,
.inode_removexattr = smack_inode_removexattr,
.inode_getsecurity = smack_inode_getsecurity,
.inode_setsecurity = smack_inode_setsecurity,
.inode_listsecurity = smack_inode_listsecurity,
.inode_getsecid = smack_inode_getsecid,
.file_permission = smack_file_permission,
.file_alloc_security = smack_file_alloc_security,
.file_free_security = smack_file_free_security,
.file_ioctl = smack_file_ioctl,
.file_lock = smack_file_lock,
.file_fcntl = smack_file_fcntl,
.mmap_file = smack_mmap_file,
.mmap_addr = cap_mmap_addr,
.file_set_fowner = smack_file_set_fowner,
.file_send_sigiotask = smack_file_send_sigiotask,
.file_receive = smack_file_receive,
.file_open = smack_file_open,
.cred_alloc_blank = smack_cred_alloc_blank,
.cred_free = smack_cred_free,
.cred_prepare = smack_cred_prepare,
.cred_transfer = smack_cred_transfer,
.kernel_act_as = smack_kernel_act_as,
.kernel_create_files_as = smack_kernel_create_files_as,
.task_setpgid = smack_task_setpgid,
.task_getpgid = smack_task_getpgid,
.task_getsid = smack_task_getsid,
.task_getsecid = smack_task_getsecid,
.task_setnice = smack_task_setnice,
.task_setioprio = smack_task_setioprio,
.task_getioprio = smack_task_getioprio,
.task_setscheduler = smack_task_setscheduler,
.task_getscheduler = smack_task_getscheduler,
.task_movememory = smack_task_movememory,
.task_kill = smack_task_kill,
.task_wait = smack_task_wait,
.task_to_inode = smack_task_to_inode,
.ipc_permission = smack_ipc_permission,
.ipc_getsecid = smack_ipc_getsecid,
.msg_msg_alloc_security = smack_msg_msg_alloc_security,
.msg_msg_free_security = smack_msg_msg_free_security,
.msg_queue_alloc_security = smack_msg_queue_alloc_security,
.msg_queue_free_security = smack_msg_queue_free_security,
.msg_queue_associate = smack_msg_queue_associate,
.msg_queue_msgctl = smack_msg_queue_msgctl,
.msg_queue_msgsnd = smack_msg_queue_msgsnd,
.msg_queue_msgrcv = smack_msg_queue_msgrcv,
.shm_alloc_security = smack_shm_alloc_security,
.shm_free_security = smack_shm_free_security,
.shm_associate = smack_shm_associate,
.shm_shmctl = smack_shm_shmctl,
.shm_shmat = smack_shm_shmat,
.sem_alloc_security = smack_sem_alloc_security,
.sem_free_security = smack_sem_free_security,
.sem_associate = smack_sem_associate,
.sem_semctl = smack_sem_semctl,
.sem_semop = smack_sem_semop,
.d_instantiate = smack_d_instantiate,
.getprocattr = smack_getprocattr,
.setprocattr = smack_setprocattr,
.unix_stream_connect = smack_unix_stream_connect,
.unix_may_send = smack_unix_may_send,
.socket_post_create = smack_socket_post_create,
#ifndef CONFIG_SECURITY_SMACK_NETFILTER
.socket_bind = smack_socket_bind,
#endif /* CONFIG_SECURITY_SMACK_NETFILTER */
.socket_connect = smack_socket_connect,
.socket_sendmsg = smack_socket_sendmsg,
.socket_sock_rcv_skb = smack_socket_sock_rcv_skb,
.socket_getpeersec_stream = smack_socket_getpeersec_stream,
.socket_getpeersec_dgram = smack_socket_getpeersec_dgram,
.sk_alloc_security = smack_sk_alloc_security,
.sk_free_security = smack_sk_free_security,
.sock_graft = smack_sock_graft,
.inet_conn_request = smack_inet_conn_request,
.inet_csk_clone = smack_inet_csk_clone,
/* key management security hooks */
#ifdef CONFIG_KEYS
.key_alloc = smack_key_alloc,
.key_free = smack_key_free,
.key_permission = smack_key_permission,
#endif /* CONFIG_KEYS */
/* Audit hooks */
#ifdef CONFIG_AUDIT
.audit_rule_init = smack_audit_rule_init,
.audit_rule_known = smack_audit_rule_known,
.audit_rule_match = smack_audit_rule_match,
.audit_rule_free = smack_audit_rule_free,
#endif /* CONFIG_AUDIT */
.ismaclabel = smack_ismaclabel,
.secid_to_secctx = smack_secid_to_secctx,
.secctx_to_secid = smack_secctx_to_secid,
.release_secctx = smack_release_secctx,
.inode_notifysecctx = smack_inode_notifysecctx,
.inode_setsecctx = smack_inode_setsecctx,
.inode_getsecctx = smack_inode_getsecctx,
};
static __init void init_smack_known_list(void)
{
/*
* Initialize rule list locks
*/
mutex_init(&smack_known_huh.smk_rules_lock);
mutex_init(&smack_known_hat.smk_rules_lock);
mutex_init(&smack_known_floor.smk_rules_lock);
mutex_init(&smack_known_star.smk_rules_lock);
mutex_init(&smack_known_invalid.smk_rules_lock);
mutex_init(&smack_known_web.smk_rules_lock);
/*
* Initialize rule lists
*/
INIT_LIST_HEAD(&smack_known_huh.smk_rules);
INIT_LIST_HEAD(&smack_known_hat.smk_rules);
INIT_LIST_HEAD(&smack_known_star.smk_rules);
INIT_LIST_HEAD(&smack_known_floor.smk_rules);
INIT_LIST_HEAD(&smack_known_invalid.smk_rules);
INIT_LIST_HEAD(&smack_known_web.smk_rules);
/*
* Create the known labels list
*/
smk_insert_entry(&smack_known_huh);
smk_insert_entry(&smack_known_hat);
smk_insert_entry(&smack_known_star);
smk_insert_entry(&smack_known_floor);
smk_insert_entry(&smack_known_invalid);
smk_insert_entry(&smack_known_web);
}
/**
* smack_init - initialize the smack system
*
* Returns 0
*/
static __init int smack_init(void)
{
struct cred *cred;
struct task_smack *tsp;
if (!security_module_enable(&smack_ops))
return 0;
smack_enabled = 1;
smack_inode_cache = KMEM_CACHE(inode_smack, 0);
if (!smack_inode_cache)
return -ENOMEM;
tsp = new_task_smack(&smack_known_floor, &smack_known_floor,
GFP_KERNEL);
if (tsp == NULL) {
kmem_cache_destroy(smack_inode_cache);
return -ENOMEM;
}
printk(KERN_INFO "Smack: Initializing.\n");
/*
* Set the security state for the initial task.
*/
cred = (struct cred *) current->cred;
cred->security = tsp;
/* initialize the smack_known_list */
init_smack_known_list();
/*
* Register with LSM
*/
if (register_security(&smack_ops))
panic("smack: Unable to register with kernel.\n");
return 0;
}
/*
* Smack requires early initialization in order to label
* all processes and objects when they are created.
*/
security_initcall(smack_init);
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