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 42BD71DF977; Wed, 19 Feb 2025 08:41:24 +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=1739954484; cv=none; b=cwozS7iLPl/8ABHhCa6aRrwm4PUZlvoM0CPWEd2wQ/h9j3U3tEVEVJQ9AQYhLQeM/47XuIeeBW5bsmqSDYyuP1MnE6j1rBqS9rX+3kU0LhTQvUx6M3v6+sYLoDQUeN5SOFJeqzasrUTlwzUmLdJJ72G4rghvTEx5VLMIu2xzpTM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739954484; c=relaxed/simple; bh=04yG23WKX5ggqdmjN07FwJOwLW+ZTz/fDei1lvxOPYI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UJldwhVQuYimr+2GyUQOp72Vb1r6CFtgork2fJzfgDGZeu8L9o+olOxxn/O4lhFWGcZv41vql5TL5oNTZGjqx4J6jOb2+6q5VY4MKgPVYY2jpn1s9pqTY3BlKprNdjYkWuZnPa7pfbEOomPV+1OCT5Y5eHF0KUwWnhIicBMtxrs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QaqsEhg+; 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="QaqsEhg+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A95FFC4CED1; Wed, 19 Feb 2025 08:41:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739954484; bh=04yG23WKX5ggqdmjN07FwJOwLW+ZTz/fDei1lvxOPYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QaqsEhg+tlexJjAbNEjmgI6EyYMGBQNHSxLUdnwycF6+O6dynu/iYR8cyGK63HMBs pJ7ZxbNJa4dIYGTQg3btPxrFXclUvO4ucIe6hCzeTyobnMFQqI+KFGLEkgxwrllnc3 T5MrAFsz/d7p2DzAY6maWlr/XFv8gBojfwX0kW74= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.13 217/274] ipv4: use RCU protection in ipv4_default_advmss() Date: Wed, 19 Feb 2025 09:27:51 +0100 Message-ID: <20250219082618.068856335@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082609.533585153@linuxfoundation.org> References: <20250219082609.533585153@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 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 71b8471c93fa0bcab911fcb65da1eb6c4f5f735f ] ipv4_default_advmss() must use RCU protection to make sure the net structure it reads does not disappear. Fixes: 2e9589ff809e ("ipv4: Namespaceify min_adv_mss sysctl knob") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250205155120.1676781-5-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/route.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 3a1467f2d553f..829c8d41aaae2 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1307,10 +1307,15 @@ static void set_class_tag(struct rtable *rt, u32 tag) static unsigned int ipv4_default_advmss(const struct dst_entry *dst) { - struct net *net = dev_net(dst->dev); unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); - unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, - net->ipv4.ip_rt_min_advmss); + unsigned int advmss; + struct net *net; + + rcu_read_lock(); + net = dev_net_rcu(dst->dev); + advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, + net->ipv4.ip_rt_min_advmss); + rcu_read_unlock(); return min(advmss, IPV4_MAX_PMTU - header_size); } -- 2.39.5