Merge tag 'tee-amdtee-fix2-for-5.6' of https://git.linaro.org/people/jens.wiklander/linux-tee into arm/fixes

tee: amdtee: out of bounds read in find_session()

* tag 'tee-amdtee-fix2-for-5.6' of https://git.linaro.org/people/jens.wiklander/linux-tee:
  tee: amdtee: out of bounds read in find_session()

Link: https://lore.kernel.org/r/20200320063446.GA9892@jade
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Author: arndb

drivers/tee/amdtee/core.c

@@ -139,6 +139,9 @@ static struct amdtee_session *find_session(struct amdtee_context_data *ctxdata,
 	u32 index = get_session_index(session);
 	struct amdtee_session *sess;
 
+	if (index >= TEE_NUM_SESSIONS)
+		return NULL;
+
 	list_for_each_entry(sess, &ctxdata->sess_list, list_node)
 		if (ta_handle == sess->ta_handle &&
 		    test_bit(index, sess->sess_mask))