In receive_protocol(), when crypto_alloc_shash() on line 3754 fails,
peer_integrity_tfm is NULL, and error handling code is executed.
In this code, crypto_free_shash() is called with NULL, which can cause a
null-pointer dereference, because:
crypto_free_shash(NULL)
crypto_ahash_tfm(NULL)
"return &NULL->base"
To fix this bug, peer_integrity_tfm is checked before calling
crypto_free_shash().
This bug is found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
---
drivers/block/drbd/drbd_receiver.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 90ebfcae0ce6..a4df2b8291f6 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3807,7 +3807,8 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in
disconnect_rcu_unlock:
rcu_read_unlock();
disconnect:
- crypto_free_shash(peer_integrity_tfm);
+ if (peer_integrity_tfm)
+ crypto_free_shash(peer_integrity_tfm);
kfree(int_dig_in);
kfree(int_dig_vv);
conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
--
2.17.0
