From 982e763ea3c301599279fdb5f0651865e4bebaf4 Mon Sep 17 00:00:00 2001 From: Baptiste Lepers Date: Thu, 7 Jan 2021 16:11:10 +1100 Subject: [PATCH] udp: Prevent reuseport_select_sock from reading uninitialized socks [ Upstream commit fd2ddef043592e7de80af53f47fa46fd3573086e ] reuse->socks[] is modified concurrently by reuseport_add_sock. To prevent reading values that have not been fully initialized, only read the array up until the last known safe index instead of incorrectly re-reading the last index of the array. Fixes: acdcecc61285f ("udp: correct reuseport selection with connected sockets") Signed-off-by: Baptiste Lepers Acked-by: Willem de Bruijn Link: https://lore.kernel.org/r/20210107051110.12247-1-baptiste.lepers@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/core/sock_reuseport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c index 40829111fe00..273c921751e4 100644 --- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -302,7 +302,7 @@ select_by_hash: i = j = reciprocal_scale(hash, socks); while (reuse->socks[i]->sk_state == TCP_ESTABLISHED) { i++; - if (i >= reuse->num_socks) + if (i >= socks) i = 0; if (i == j) goto out;