From 83cf5c68d663fc78ce529c41bf24f9f6be88bef4 Mon Sep 17 00:00:00 2001
From: Magnus Karlsson <magnus.karlsson@intel.com>
Date: Wed, 2 Sep 2020 09:36:04 +0200
Subject: [PATCH] xsk: Fix use-after-free in failed shared_umem bind
Fix use-after-free when a shared umem bind fails. The code incorrectly
tried to free the allocated buffer pool both in the bind code and then
later also when the socket was released. Fix this by setting the
buffer pool pointer to NULL after the bind code has freed the pool, so
that the socket release code will not try to free the pool. This is
the same solution as the regular, non-shared umem code path has. This
was missing from the shared umem path.
Fixes: b5aea28dca13 ("xsk: Add shared umem support between queue ids")
Reported-by: syzbot+5334f62e4d22804e646a@syzkaller.appspotmail.com
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1599032164-25684-1-git-send-email-magnus.karlsson@intel.com
---
net/xdp/xsk.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 07c32276c527a..3895697f85403 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -711,6 +711,7 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
dev, qid);
if (err) {
xp_destroy(xs->pool);
+ xs->pool = NULL;
sockfd_put(sock);
goto out_unlock;
}
--
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