[64/89] AppArmor: Fix sleep in invalid context from task_setrlimit

From: Greg KH
Date: Thu Jun 16 2011 - 03:33:00 EST

2.6.39-stable review patch. If anyone has any objections, please let us know.


From: John Johansen <john.johansen@xxxxxxxxxxxxx>

commit 1780f2d3839a0d3eb85ee014a708f9e2c8f8ba0e upstream.

Affected kernels 2.6.36 - 3.0

AppArmor may do a GFP_KERNEL memory allocation with task_lock(tsk->group_leader);
held when called from security_task_setrlimit. This will only occur when the
task's current policy has been replaced, and the task's creds have not been
updated before entering the LSM security_task_setrlimit() hook.

BUG: sleeping function called from invalid context at mm/slub.c:847
in_atomic(): 1, irqs_disabled(): 0, pid: 1583, name: cupsd
2 locks held by cupsd/1583:
#0: (tasklist_lock){.+.+.+}, at: [<ffffffff8104dafa>] do_prlimit+0x61/0x189
#1: (&(&p->alloc_lock)->rlock){+.+.+.}, at: [<ffffffff8104db2d>]
Pid: 1583, comm: cupsd Not tainted 3.0.0-rc2-git1 #7
Call Trace:
[<ffffffff8102ebf2>] __might_sleep+0x10d/0x112
[<ffffffff810e6f46>] slab_pre_alloc_hook.isra.49+0x2d/0x33
[<ffffffff810e7bc4>] kmem_cache_alloc+0x22/0x132
[<ffffffff8105b6e6>] prepare_creds+0x35/0xe4
[<ffffffff811c0675>] aa_replace_current_profile+0x35/0xb2
[<ffffffff811c4d2d>] aa_current_profile+0x45/0x4c
[<ffffffff811c4d4d>] apparmor_task_setrlimit+0x19/0x3a
[<ffffffff811beaa5>] security_task_setrlimit+0x11/0x13
[<ffffffff8104db6b>] do_prlimit+0xd2/0x189
[<ffffffff8104dea9>] sys_setrlimit+0x3b/0x48
[<ffffffff814062bb>] system_call_fastpath+0x16/0x1b

Signed-off-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
Reported-by: Miles Lane <miles.lane@xxxxxxxxx>
Signed-off-by: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

security/apparmor/lsm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -612,7 +612,7 @@ static int apparmor_setprocattr(struct t
static int apparmor_task_setrlimit(struct task_struct *task,
unsigned int resource, struct rlimit *new_rlim)
- struct aa_profile *profile = aa_current_profile();
+ struct aa_profile *profile = __aa_current_profile();
int error = 0;

if (!unconfined(profile))

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