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| author | David Howells <dhowells@redhat.com> | 2008-11-14 10:39:19 +1100 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2008-11-14 10:39:19 +1100 |
| commit | c69e8d9c01db2adc503464993c358901c9af9de4 (patch) | |
| tree | bed94aaa9aeb7a7834d1c880f72b62a11a752c78 /kernel/cgroup.c | |
| parent | 86a264abe542cfececb4df129bc45a0338d8cdb9 (diff) | |
| download | linux-c69e8d9c01db2adc503464993c358901c9af9de4.tar.gz linux-c69e8d9c01db2adc503464993c358901c9af9de4.tar.bz2 linux-c69e8d9c01db2adc503464993c358901c9af9de4.zip | |
CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index e210526e6401..a512a75a5560 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1279,7 +1279,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) { struct task_struct *tsk; - uid_t euid; + const struct cred *cred = current_cred(), *tcred; int ret; if (pid) { @@ -1289,16 +1289,16 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) rcu_read_unlock(); return -ESRCH; } - get_task_struct(tsk); - rcu_read_unlock(); - euid = current_euid(); - if (euid && - euid != tsk->cred->uid && - euid != tsk->cred->suid) { - put_task_struct(tsk); + tcred = __task_cred(tsk); + if (cred->euid && + cred->euid != tcred->uid && + cred->euid != tcred->suid) { + rcu_read_unlock(); return -EACCES; } + get_task_struct(tsk); + rcu_read_unlock(); } else { tsk = current; get_task_struct(tsk); |