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authorPaul Moore <paul@paul-moore.com>2021-09-29 18:01:21 +0300
committerPaul Moore <paul@paul-moore.com>2021-11-23 01:52:47 +0300
commit6326948f940dc3f77066d5cdc44ba6afe67830c0 (patch)
tree13976c9bfaedfc1105ac27a1efaf9c752d3949ee /security/smack
parentfa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff)
downloadlinux-6326948f940dc3f77066d5cdc44ba6afe67830c0.tar.xz
lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
The security_task_getsecid_subj() LSM hook invites misuse by allowing callers to specify a task even though the hook is only safe when the current task is referenced. Fix this by removing the task_struct argument to the hook, requiring LSM implementations to use the current task. While we are changing the hook declaration we also rename the function to security_current_getsecid_subj() in an effort to reinforce that the hook captures the subjective credentials of the current task and not an arbitrary task on the system. Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security/smack')
-rw-r--r--security/smack/smack.h16
-rw-r--r--security/smack/smack_lsm.c9
2 files changed, 4 insertions, 21 deletions
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 99c3422596ab..fc837dcebf96 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -389,22 +389,6 @@ static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
return tsp->smk_task;
}
-static inline struct smack_known *smk_of_task_struct_subj(
- const struct task_struct *t)
-{
- struct smack_known *skp;
- const struct cred *cred;
-
- rcu_read_lock();
-
- cred = rcu_dereference(t->cred);
- skp = smk_of_task(smack_cred(cred));
-
- rcu_read_unlock();
-
- return skp;
-}
-
static inline struct smack_known *smk_of_task_struct_obj(
const struct task_struct *t)
{
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index efd35b07c7f8..14b279cc75c9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2067,15 +2067,14 @@ static int smack_task_getsid(struct task_struct *p)
}
/**
- * smack_task_getsecid_subj - get the subjective secid of the task
- * @p: the task
+ * smack_current_getsecid_subj - get the subjective secid of the current task
* @secid: where to put the result
*
* Sets the secid to contain a u32 version of the task's subjective smack label.
*/
-static void smack_task_getsecid_subj(struct task_struct *p, u32 *secid)
+static void smack_current_getsecid_subj(u32 *secid)
{
- struct smack_known *skp = smk_of_task_struct_subj(p);
+ struct smack_known *skp = smk_of_current();
*secid = skp->smk_secid;
}
@@ -4807,7 +4806,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(task_setpgid, smack_task_setpgid),
LSM_HOOK_INIT(task_getpgid, smack_task_getpgid),
LSM_HOOK_INIT(task_getsid, smack_task_getsid),
- LSM_HOOK_INIT(task_getsecid_subj, smack_task_getsecid_subj),
+ LSM_HOOK_INIT(current_getsecid_subj, smack_current_getsecid_subj),
LSM_HOOK_INIT(task_getsecid_obj, smack_task_getsecid_obj),
LSM_HOOK_INIT(task_setnice, smack_task_setnice),
LSM_HOOK_INIT(task_setioprio, smack_task_setioprio),