xfrm: NULL dereference on allocation failure

The default error code in pfkey_msg2xfrm_state() is -ENOBUFS.  We
added a new call to security_xfrm_state_alloc() which sets "err" to zero
so there several places where we can return ERR_PTR(0) if kmalloc()
fails.  The caller is expecting error pointers so it leads to a NULL
dereference.

Fixes: df71837d5024 ("[LSM-IPSec]: Security association restriction.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2b82adac5d8edae4a7e840afceb334b20217cf6c..b1432b6680338cf60942f3dd5567a6c7a11a603f 100644 (file)
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1157,6 +1157,7 @@ static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
                        goto out;
        }
 
+       err = -ENOBUFS;
        key = ext_hdrs[SADB_EXT_KEY_AUTH - 1];
        if (sa->sadb_sa_auth) {
                int keysize = 0;