Commit 83cf5c68 authored Sep 02, 2020 by Magnus Karlsson Committed by Daniel Borkmann Sep 02, 2020

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: b5aea28d ("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

parent 1d6fd78a

net/xdp/xsk.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}