From 8c7188b23474cca017b3ef354c4a58456f68303a Mon Sep 17 00:00:00 2001 From: Quentin Casasnovas Date: Tue, 24 Nov 2015 17:13:21 -0500 Subject: RDS: fix race condition when sending a message on unbound socket Sasha's found a NULL pointer dereference in the RDS connection code when sending a message to an apparently unbound socket. The problem is caused by the code checking if the socket is bound in rds_sendmsg(), which checks the rs_bound_addr field without taking a lock on the socket. This opens a race where rs_bound_addr is temporarily set but where the transport is not in rds_bind(), leading to a NULL pointer dereference when trying to dereference 'trans' in __rds_conn_create(). Vegard wrote a reproducer for this issue, so kindly ask him to share if you're interested. I cannot reproduce the NULL pointer dereference using Vegard's reproducer with this patch, whereas I could without. Complete earlier incomplete fix to CVE-2015-6937: 74e98eb08588 ("RDS: verify the underlying transport exists before creating a connection") Cc: David S. Miller Cc: stable@vger.kernel.org Reviewed-by: Vegard Nossum Reviewed-by: Sasha Levin Acked-by: Santosh Shilimkar Signed-off-by: Quentin Casasnovas Signed-off-by: David S. Miller --- net/rds/connection.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'net/rds/connection.c') diff --git a/net/rds/connection.c b/net/rds/connection.c index d4564036a339..e3b118cae81d 100644 --- a/net/rds/connection.c +++ b/net/rds/connection.c @@ -186,12 +186,6 @@ static struct rds_connection *__rds_conn_create(struct net *net, } } - if (trans == NULL) { - kmem_cache_free(rds_conn_slab, conn); - conn = ERR_PTR(-ENODEV); - goto out; - } - conn->c_trans = trans; ret = trans->conn_alloc(conn, gfp); -- cgit v1.2.3