From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1916430DD02; Tue, 2 Sep 2025 13:46:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820816; cv=none; b=gOdn1OydF67n1QpLzsVBkSoI42QvKPqnqtIqStGm93bLLyvMiD8926mmHaoVPORG0Qigs3sFLp7H1A9IiTP1TtRS2VPjSwtZ/t9J+2eSAmk8sxAoSBjyx3TSmZh1KZbPhObPYef5Y5YhEUIxpSXYCLcsMAzFyji85n37s085GNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820816; c=relaxed/simple; bh=t/roX2jckQEEipOjMy4Xh/8eaxa/TfrA72LJGgLOwJs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=osQFJFj2po4FFA/UR90aqt39BTRo1ty6pZy7FRTgpdp3XI2FnNnbg+1xa4jpPFGxHMOsGGaXTaLeYGYDuzp3VYjBwl8A0B5fZqbEu/4xakIQIhu5P6UHnJH6Z7feRtKKjWv95G59oUOqStE2vZkNPzmRHm3QCsNc37QogleXRrg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XlIX6Be+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XlIX6Be+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 456EDC4CEED; Tue, 2 Sep 2025 13:46:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756820815; bh=t/roX2jckQEEipOjMy4Xh/8eaxa/TfrA72LJGgLOwJs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XlIX6Be+qk2xjVoh7rzPN0npy/Skh6wk5v9bPsLqGHusMkQEUsUm8Prm0NVz5RGyM +9TlGHeh+hGmw3islSWbRyYfyBbX5qKB1EgnxA76kVag6yrzvoIZbEaYq6lnjskp87 bxZTzYZGIctQtwcJhTEHAbsLv+BlL+eSISQnXnnM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Brett A C Sheffield , Oscar Maes , David Ahern , Paolo Abeni , Sasha Levin Subject: [PATCH 5.4 05/23] net: ipv4: fix regression in local-broadcast routes Date: Tue, 2 Sep 2025 15:21:51 +0200 Message-ID: <20250902131924.939380172@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250902131924.720400762@linuxfoundation.org> References: <20250902131924.720400762@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oscar Maes [ 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 --- net/ipv4/route.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 80612f73ff531..eb83ce4b845ab 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2365,12 +2365,16 @@ 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; -- 2.50.1