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 9D65C304BA0; Tue, 2 Sep 2025 13:44:50 +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=1756820690; cv=none; b=hESaNnEZg4KNaZOAd+4+sQsT4Laz77DGuE2c+f8hi59PXy5FOiUhXPw1U/Yu2wv5aZROzpndj7DsmYRO0jGrEcN/+0dMqcgCZkCBV84LRzU0JLXBckXqPDbPZaPM3eCZgVBc916uw/FOLe3N3VdqHXYDDlIEq+KR0ROrm3Sx+ug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756820690; c=relaxed/simple; bh=bjEUjlhmSbA5hM+RAm3IMNVyKnoGbWfh0xi84N+IyHo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P7BWo5k3YNpyW4TMohnq6xGrLyhic21yt3CE5KdVky2LfrQVTJKkf9p+PnITCcek7yK4HK3reN+SKop4yZe8TrxQ6dNZLoeuOXr4gCOm8dIoVjI+ndYw7HgkWwHWBukHy3NTjz52PdVMeENoF8MUsaAa17jKGowaf7c4gVEXN1E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Df6yvQcd; 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="Df6yvQcd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E259C4CEED; Tue, 2 Sep 2025 13:44:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756820690; bh=bjEUjlhmSbA5hM+RAm3IMNVyKnoGbWfh0xi84N+IyHo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Df6yvQcdvNu2USLYImS4mPHhNzE7lvMQ1UvGgR5dSKTvKLJ6wi/lFbbdkTxGs76zv G7PEGAuGyA1aI2wxTwnL1Dj9wrLDNJ3PWu4cXj2NNuXfwSdzTjxSFG37srh5fYPkj9 FT4MUH9r/zjHVhKavbsVa7rF/pJOPkqjX2/Kvnf8= 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 5.10 08/34] net: ipv4: fix regression in local-broadcast routes Date: Tue, 2 Sep 2025 15:21:34 +0200 Message-ID: <20250902131926.947399123@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250902131926.607219059@linuxfoundation.org> References: <20250902131926.607219059@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-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 7c4479adbf325..fbaed08600f0f 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2452,12 +2452,16 @@ 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