From a3a8784454692dd72e5d5d34dcdab17b4420e74c Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Mon, 29 Dec 2014 09:39:01 -0500 Subject: [PATCH 1/2] KEYS: close race between key lookup and freeing When a key is being garbage collected, it's key->user would get put before the ->destroy() callback is called, where the key is removed from it's respective tracking structures. This leaves a key hanging in a semi-invalid state which leaves a window open for a different task to try an access key->user. An example is find_keyring_by_name() which would dereference key->user for a key that is in the process of being garbage collected (where key->user was freed but ->destroy() wasn't called yet - so it's still present in the linked list). This would cause either a panic, or corrupt memory. Fixes CVE-2014-9529. Signed-off-by: Sasha Levin Signed-off-by: David Howells --- security/keys/gc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/security/keys/gc.c b/security/keys/gc.c index 9609a7f0faea..c7952375ac53 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -148,12 +148,12 @@ static noinline void key_gc_unused_keys(struct list_head *keys) if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) atomic_dec(&key->user->nikeys); - key_user_put(key->user); - /* now throw away the key memory */ if (key->type->destroy) key->type->destroy(key); + key_user_put(key->user); + kfree(key->description); #ifdef KEY_DEBUGGING From 990428b8ead311c68a850ead7ec8557a10b8893a Mon Sep 17 00:00:00 2001 From: Pranith Kumar Date: Tue, 30 Dec 2014 00:46:21 -0500 Subject: [PATCH 2/2] assoc_array: Include rcupdate.h for call_rcu() definition Include rcupdate.h header to provide call_rcu() definition. This was implicitly being provided by slab.h file which include srcu.h somewhere in its include hierarchy which in-turn included rcupdate.h. Lately, tinification effort added support to remove srcu entirely because of which we are encountering build errors like lib/assoc_array.c: In function 'assoc_array_apply_edit': lib/assoc_array.c:1426:2: error: implicit declaration of function 'call_rcu' [-Werror=implicit-function-declaration] cc1: some warnings being treated as errors Fix these by including rcupdate.h explicitly. Signed-off-by: Pranith Kumar Reported-by: Scott Wood --- lib/assoc_array.c | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/assoc_array.c b/lib/assoc_array.c index 2404d03e251a..03dd576e6773 100644 --- a/lib/assoc_array.c +++ b/lib/assoc_array.c @@ -11,6 +11,7 @@ * 2 of the Licence, or (at your option) any later version. */ //#define DEBUG +#include #include #include #include