The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

a1221703a0f7 ("sctp: sctp_sock_filter(): avoid list_entry() on possibly empty list")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a1221703a0f75a9d81748c516457e0fc76951496 Mon Sep 17 00:00:00 2001 From: Pietro Borrello borrello@diag.uniroma1.it Date: Thu, 9 Feb 2023 12:13:05 +0000 Subject: [PATCH] sctp: sctp_sock_filter(): avoid list_entry() on possibly empty list

Use list_is_first() to check whether tsp->asoc matches the first element of ep->asocs, as the list is not guaranteed to have an entry.

Fixes: 8f840e47f190 ("sctp: add the sctp_diag.c file") Signed-off-by: Pietro Borrello borrello@diag.uniroma1.it Acked-by: Xin Long lucien.xin@gmail.com Link: https://lore.kernel.org/r/20230208-sctp-filter-v2-1-6e1f4017f326@diag.unirom... Signed-off-by: Jakub Kicinski kuba@kernel.org

diff --git a/net/sctp/diag.c b/net/sctp/diag.c index a557009e9832..c3d6b92dd386 100644 --- a/net/sctp/diag.c +++ b/net/sctp/diag.c @@ -343,11 +343,9 @@ static int sctp_sock_filter(struct sctp_endpoint *ep, struct sctp_transport *tsp struct sctp_comm_param *commp = p; struct sock *sk = ep->base.sk; const struct inet_diag_req_v2 *r = commp->r; - struct sctp_association *assoc = - list_entry(ep->asocs.next, struct sctp_association, asocs);

/* find the ep only once through the transports by this condition */ - if (tsp->asoc != assoc) + if (!list_is_first(&tsp->asoc->asocs, &ep->asocs)) return 0;

if (r->sdiag_family != AF_UNSPEC && sk->sk_family != r->sdiag_family)