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apparmor: allow ptrace checks to be finer grained than just capability

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Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen 2017-06-09 14:38:35 -07:00
parent b2d09ae449
commit 290f458a4f
3 changed files with 68 additions and 0 deletions
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6
security/apparmor/apparmorfs.c
View File

@ -2086,6 +2086,11 @@ static struct aa_sfs_entry aa_sfs_entry_file[] = {
{ }
};
static struct aa_sfs_entry aa_sfs_entry_ptrace[] = {
AA_SFS_FILE_STRING("mask", "read trace"),
{ }
};
static struct aa_sfs_entry aa_sfs_entry_domain[] = {
AA_SFS_FILE_BOOLEAN("change_hat", 1),
AA_SFS_FILE_BOOLEAN("change_hatv", 1),
@ -2125,6 +2130,7 @@ static struct aa_sfs_entry aa_sfs_entry_features[] = {
AA_SFS_FILE_U64("capability", VFS_CAP_FLAGS_MASK),
AA_SFS_DIR("rlimit", aa_sfs_entry_rlimit),
AA_SFS_DIR("caps", aa_sfs_entry_caps),
AA_SFS_DIR("ptrace", aa_sfs_entry_ptrace),
AA_SFS_DIR("query", aa_sfs_entry_query),
{ }
};

6
security/apparmor/include/ipc.h
View File

@ -21,6 +21,12 @@ struct aa_profile;
#define AA_PTRACE_TRACE MAY_WRITE
#define AA_PTRACE_READ MAY_READ
#define AA_MAY_BE_TRACED AA_MAY_APPEND
#define AA_MAY_BE_READ AA_MAY_CREATE
#define PTRACE_PERM_SHIFT 2
#define AA_PTRACE_PERM_MASK (AA_PTRACE_READ | AA_PTRACE_TRACE | \
AA_MAY_BE_READ | AA_MAY_BE_TRACED)
int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
u32 request);

56
security/apparmor/ipc.c
View File

@ -21,20 +21,76 @@
#include "include/policy.h"
#include "include/ipc.h"
/**
* audit_ptrace_mask - convert mask to permission string
* @buffer: buffer to write string to (NOT NULL)
* @mask: permission mask to convert
*/
static void audit_ptrace_mask(struct audit_buffer *ab, u32 mask)
{
switch (mask) {
case MAY_READ:
audit_log_string(ab, "read");
break;
case MAY_WRITE:
audit_log_string(ab, "trace");
break;
case AA_MAY_BE_READ:
audit_log_string(ab, "readby");
break;
case AA_MAY_BE_TRACED:
audit_log_string(ab, "tracedby");
break;
}
}
/* call back to audit ptrace fields */
static void audit_ptrace_cb(struct audit_buffer *ab, void *va)
{
struct common_audit_data *sa = va;
if (aad(sa)->request & AA_PTRACE_PERM_MASK) {
audit_log_format(ab, " requested_mask=");
audit_ptrace_mask(ab, aad(sa)->request);
if (aad(sa)->denied & AA_PTRACE_PERM_MASK) {
audit_log_format(ab, " denied_mask=");
audit_ptrace_mask(ab, aad(sa)->denied);
}
}
audit_log_format(ab, " peer=");
aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
FLAGS_NONE, GFP_ATOMIC);
}
/* TODO: conditionals */
static int profile_ptrace_perm(struct aa_profile *profile,
struct aa_profile *peer, u32 request,
struct common_audit_data *sa)
{
struct aa_perms perms = { };
/* need because of peer in cross check */
if (profile_unconfined(profile) ||
!PROFILE_MEDIATES(profile, AA_CLASS_PTRACE))
return 0;
aad(sa)->peer = &peer->label;
aa_profile_match_label(profile, &peer->label, AA_CLASS_PTRACE, request,
&perms);
aa_apply_modes_to_perms(profile, &perms);
return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb);
}
static int cross_ptrace_perm(struct aa_profile *tracer,
struct aa_profile *tracee, u32 request,
struct common_audit_data *sa)
{
if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE))
return xcheck(profile_ptrace_perm(tracer, tracee, request, sa),
profile_ptrace_perm(tracee, tracer,
request << PTRACE_PERM_SHIFT,
sa));
/* policy uses the old style capability check for ptrace */
if (profile_unconfined(tracer) || tracer == tracee)
return 0;