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apparmor: move resource checks to using labels

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Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen 2017-06-09 14:15:20 -07:00
parent c70c86c421
commit 86b92cb782
3 changed files with 79 additions and 41 deletions
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4
security/apparmor/include/resource.h
View File

@ -37,10 +37,10 @@ struct aa_rlimit {
extern struct aa_sfs_entry aa_sfs_entry_rlimit[];
int aa_map_resource(int resource);
int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *,
int aa_task_setrlimit(struct aa_label *label, struct task_struct *task,
unsigned int resource, struct rlimit *new_rlim);
void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new);
void __aa_transition_rlimits(struct aa_label *old, struct aa_label *new);
static inline void aa_free_rlimit_rules(struct aa_rlimit *rlims)
{

6
security/apparmor/lsm.c
View File

@ -625,8 +625,7 @@ static void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
current->pdeath_signal = 0;
/* reset soft limits and set hard limits for the new label */
__aa_transition_rlimits(labels_profile(label),
labels_profile(new_ctx->label));
__aa_transition_rlimits(label, new_ctx->label);
}
/**
@ -646,8 +645,7 @@ static int apparmor_task_setrlimit(struct task_struct *task,
int error = 0;
if (!unconfined(label))
error = aa_task_setrlimit(labels_profile(label), task,
resource, new_rlim);
error = aa_task_setrlimit(label, task, resource, new_rlim);
__end_current_label_crit_section(label);
return error;

110
security/apparmor/resource.c
View File

@ -13,6 +13,7 @@
*/
#include <linux/audit.h>
#include <linux/security.h>
#include "include/audit.h"
#include "include/context.h"
@ -36,6 +37,11 @@ static void audit_cb(struct audit_buffer *ab, void *va)
audit_log_format(ab, " rlimit=%s value=%lu",
rlim_names[aad(sa)->rlim.rlim], aad(sa)->rlim.max);
if (aad(sa)->peer) {
audit_log_format(ab, " peer=");
aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
FLAGS_NONE, GFP_ATOMIC);
}
}
/**
@ -48,13 +54,17 @@ static void audit_cb(struct audit_buffer *ab, void *va)
* Returns: 0 or sa->error else other error code on failure
*/
static int audit_resource(struct aa_profile *profile, unsigned int resource,
unsigned long value, int error)
unsigned long value, struct aa_label *peer,
const char *info, int error)
{
DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SETRLIMIT);
aad(&sa)->rlim.rlim = resource;
aad(&sa)->rlim.max = value;
aad(&sa)->peer = peer;
aad(&sa)->info = info;
aad(&sa)->error = error;
return aa_audit(AUDIT_APPARMOR_AUTO, profile, &sa, audit_cb);
}
@ -72,9 +82,21 @@ int aa_map_resource(int resource)
return rlim_map[resource];
}
static int profile_setrlimit(struct aa_profile *profile, unsigned int resource,
struct rlimit *new_rlim)
{
int e = 0;
if (profile->rlimits.mask & (1 << resource) && new_rlim->rlim_max >
profile->rlimits.limits[resource].rlim_max)
e = -EACCES;
return audit_resource(profile, resource, new_rlim->rlim_max, NULL, NULL,
e);
}
/**
* aa_task_setrlimit - test permission to set an rlimit
* @profile - profile confining the task (NOT NULL)
* @label - label confining the task (NOT NULL)
* @task - task the resource is being set on
* @resource - the resource being set
* @new_rlim - the new resource limit (NOT NULL)
@ -83,14 +105,15 @@ int aa_map_resource(int resource)
*
* Returns: 0 or error code if setting resource failed
*/
int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task,
int aa_task_setrlimit(struct aa_label *label, struct task_struct *task,
unsigned int resource, struct rlimit *new_rlim)
{
struct aa_label *task_label;
struct aa_profile *profile;
struct aa_label *peer;
int error = 0;
rcu_read_lock();
task_label = aa_get_newest_cred_label((__task_cred(task)));
peer = aa_get_newest_cred_label(__task_cred(task));
rcu_read_unlock();
/* TODO: extend resource control to handle other (non current)
@ -99,53 +122,70 @@ int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task,
* the same profile or that the task setting the resource of another
* task has CAP_SYS_RESOURCE.
*/
if ((profile != labels_profile(task_label) &&
aa_capable(&profile->label, CAP_SYS_RESOURCE, 1)) ||
(profile->rlimits.mask & (1 << resource) &&
new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
error = -EACCES;
aa_put_label(task_label);
if (label != peer &&
!aa_capable(label, CAP_SYS_RESOURCE, SECURITY_CAP_NOAUDIT))
error = fn_for_each(label, profile,
audit_resource(profile, resource,
new_rlim->rlim_max, peer,
"cap_sys_resoure", -EACCES));
else
error = fn_for_each_confined(label, profile,
profile_setrlimit(profile, resource, new_rlim));
aa_put_label(peer);
return audit_resource(profile, resource, new_rlim->rlim_max, error);
return error;
}
/**
* __aa_transition_rlimits - apply new profile rlimits
* @old: old profile on task (NOT NULL)
* @new: new profile with rlimits to apply (NOT NULL)
* @old_l: old label on task (NOT NULL)
* @new_l: new label with rlimits to apply (NOT NULL)
*/
void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new)
void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l)
{
unsigned int mask = 0;
struct rlimit *rlim, *initrlim;
int i;
struct aa_profile *old, *new;
struct label_it i;
/* for any rlimits the profile controlled reset the soft limit
* to the less of the tasks hard limit and the init tasks soft limit
old = labels_profile(old_l);
new = labels_profile(new_l);
/* for any rlimits the profile controlled, reset the soft limit
* to the lesser of the tasks hard limit and the init tasks soft limit
*/
if (old->rlimits.mask) {
for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
if (old->rlimits.mask & mask) {
rlim = current->signal->rlim + i;
initrlim = init_task.signal->rlim + i;
rlim->rlim_cur = min(rlim->rlim_max,
initrlim->rlim_cur);
label_for_each_confined(i, old_l, old) {
if (old->rlimits.mask) {
int j;
for (j = 0, mask = 1; j < RLIM_NLIMITS; j++,
mask <<= 1) {
if (old->rlimits.mask & mask) {
rlim = current->signal->rlim + j;
initrlim = init_task.signal->rlim + j;
rlim->rlim_cur = min(rlim->rlim_max,
initrlim->rlim_cur);
}
}
}
}
/* set any new hard limits as dictated by the new profile */
if (!new->rlimits.mask)
return;
for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
if (!(new->rlimits.mask & mask))
continue;
label_for_each_confined(i, new_l, new) {
int j;
rlim = current->signal->rlim + i;
rlim->rlim_max = min(rlim->rlim_max,
new->rlimits.limits[i].rlim_max);
/* soft limit should not exceed hard limit */
rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
if (!new->rlimits.mask)
continue;
for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) {
if (!(new->rlimits.mask & mask))
continue;
rlim = current->signal->rlim + j;
rlim->rlim_max = min(rlim->rlim_max,
new->rlimits.limits[j].rlim_max);
/* soft limit should not exceed hard limit */
rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
}
}
}