From: Oscar Maes Date: Wed, 27 Aug 2025 06:23:21 +0000 (+0200) Subject: net: ipv4: fix regression in local-broadcast routes X-Git-Tag: v6.12.45~77 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=81ff76c1b08827bc81779400a3640f102a9a9ade;p=thirdparty%2Fkernel%2Fstable.git net: ipv4: fix regression in local-broadcast routes [ Upstream commit 5189446ba995556eaa3755a6e875bc06675b88bd ] Commit 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes") introduced a regression where local-broadcast packets would have their gateway set in __mkroute_output, which was caused by fi = NULL being removed. Fix this by resetting the fib_info for local-broadcast packets. This preserves the intended changes for directed-broadcast packets. Cc: stable@vger.kernel.org Fixes: 9e30ecf23b1b ("net: ipv4: fix incorrect MTU in broadcast routes") Reported-by: Brett A C Sheffield Closes: https://lore.kernel.org/regressions/20250822165231.4353-4-bacs@librecast.net Signed-off-by: Oscar Maes Reviewed-by: David Ahern Link: https://patch.msgid.link/20250827062322.4807-1-oscmaes92@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 9a5c9497b3931..261ddb6542a40 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2532,12 +2532,16 @@ static struct rtable *__mkroute_output(const struct fib_result *res, !netif_is_l3_master(dev_out)) return ERR_PTR(-EINVAL); - if (ipv4_is_lbcast(fl4->daddr)) + if (ipv4_is_lbcast(fl4->daddr)) { type = RTN_BROADCAST; - else if (ipv4_is_multicast(fl4->daddr)) + + /* reset fi to prevent gateway resolution */ + fi = NULL; + } else if (ipv4_is_multicast(fl4->daddr)) { type = RTN_MULTICAST; - else if (ipv4_is_zeronet(fl4->daddr)) + } else if (ipv4_is_zeronet(fl4->daddr)) { return ERR_PTR(-EINVAL); + } if (dev_out->flags & IFF_LOOPBACK) flags |= RTCF_LOCAL;