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authorDavid Howells <dhowells@redhat.com>2011-11-15 22:09:45 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2011-11-15 22:32:38 -0200
commit9f35a33b8d06263a165efe3541d9aa0cdbd70b3b (patch)
tree2825d1bf9ea73d22e4cab45bb2cdc021c6e09380
parentcfcfc9eca2bcbd26a8e206baeb005b055dbf8e37 (diff)
downloadlinaro-lsk-9f35a33b8d06263a165efe3541d9aa0cdbd70b3b.tar.gz
KEYS: Fix a NULL pointer deref in the user-defined key type
Fix a NULL pointer deref in the user-defined key type whereby updating a negative key into a fully instantiated key will cause an oops to occur when the code attempts to free the non-existent old payload. This results in an oops that looks something like the following: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffff81085fa1>] __call_rcu+0x11/0x13e PGD 3391d067 PUD 3894a067 PMD 0 Oops: 0002 [#1] SMP CPU 1 Pid: 4354, comm: keyctl Not tainted 3.1.0-fsdevel+ #1140 /DG965RY RIP: 0010:[<ffffffff81085fa1>] [<ffffffff81085fa1>] __call_rcu+0x11/0x13e RSP: 0018:ffff88003d591df8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000006e RDX: ffffffff8161d0c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88003d591e18 R08: 0000000000000000 R09: ffffffff8152fa6c R10: 0000000000000000 R11: 0000000000000300 R12: ffff88003b8f9538 R13: ffffffff8161d0c0 R14: ffff88003b8f9d50 R15: ffff88003c69f908 FS: 00007f97eb18c720(0000) GS:ffff88003bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 000000003d47a000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process keyctl (pid: 4354, threadinfo ffff88003d590000, task ffff88003c78a040) Stack: ffff88003e0ffde0 ffff88003b8f9538 0000000000000001 ffff88003b8f9d50 ffff88003d591e28 ffffffff810860f0 ffff88003d591e68 ffffffff8117bfea ffff88003d591e68 ffffffff00000000 ffff88003e0ffde1 ffff88003e0ffde0 Call Trace: [<ffffffff810860f0>] call_rcu_sched+0x10/0x12 [<ffffffff8117bfea>] user_update+0x8d/0xa2 [<ffffffff8117723a>] key_create_or_update+0x236/0x270 [<ffffffff811789b1>] sys_add_key+0x123/0x17e [<ffffffff813b84bb>] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Acked-by: Neil Horman <nhorman@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: James Morris <jmorris@namei.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--security/keys/user_defined.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 5b366d7af3c..69ff52c08e9 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -102,7 +102,8 @@ int user_update(struct key *key, const void *data, size_t datalen)
key->expiry = 0;
}
- kfree_rcu(zap, rcu);
+ if (zap)
+ kfree_rcu(zap, rcu);
error:
return ret;