[PATCH 4.9 138/172] xfrm: NULL dereference on allocation failure

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit e747f64336fc15e1c823344942923195b800aa1e upstream.

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@xxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/key/af_key.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1135,6 +1135,7 @@ static struct xfrm_state * pfkey_msg2xfr
 			goto out;
 	}
 
+	err = -ENOBUFS;
 	key = ext_hdrs[SADB_EXT_KEY_AUTH - 1];
 	if (sa->sadb_sa_auth) {
 		int keysize = 0;