From: Chuck Lever <chuck.lever@oracle.com>
Date: Wed, 19 Jun 2019 10:32:38 -0400
Subject: xprtrdma: Fix use-after-free in rpcrdma_post_recvs
Patch-mainline: v5.3-rc1
Git-commit: 2d0abe36cf13fb7b577949fd1539326adddcc9bc
References: bsc#1103992 FATE#326009
Dereference wr->next /before/ the memory backing wr has been
released. This issue was found by code inspection. It is not
expected to be a significant problem because it is in an error
path that is almost never executed.
Fixes: 7c8d9e7c8863 ("xprtrdma: Move Receive posting to ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/sunrpc/xprtrdma/verbs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1553,10 +1553,11 @@ rpcrdma_post_recvs(struct rpcrdma_xprt *
rc = ib_post_recv(r_xprt->rx_ia.ri_id->qp, wr,
(const struct ib_recv_wr **)&bad_wr);
if (rc) {
- for (wr = bad_wr; wr; wr = wr->next) {
+ for (wr = bad_wr; wr;) {
struct rpcrdma_rep *rep;
rep = container_of(wr, struct rpcrdma_rep, rr_recv_wr);
+ wr = wr->next;
rpcrdma_recv_buffer_put(rep);
--count;
}