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 E5A439446 for ; Sun, 13 Aug 2023 21:38:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C879C433C7; Sun, 13 Aug 2023 21:38:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691962732; bh=mQ5NRXZvFY+HN6Rd4xPvUZJ1L/QuP3EgdSYFA9qLev8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iEQuINmvGTLPmNKAOfpsE6J04aeNblC3A2VCeLnILeqwmVID9ai0J8+XReJZa2CNy eyHrSJNgb70FoUG2Xj00ouTI645aeS3xJafUon7MTZcd1qejJ4jtivU4H3iuT8shIB kcoL0A/qMCFBGgMSU8iro0oMokSBTqDnGcH4T7xc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Jakub Kicinski Subject: [PATCH 6.1 092/149] tunnels: fix kasan splat when generating ipv4 pmtu error Date: Sun, 13 Aug 2023 23:18:57 +0200 Message-ID: <20230813211721.544957780@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230813211718.757428827@linuxfoundation.org> References: <20230813211718.757428827@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Florian Westphal commit 6a7ac3d20593865209dceb554d8b3f094c6bd940 upstream. If we try to emit an icmp error in response to a nonliner skb, we get BUG: KASAN: slab-out-of-bounds in ip_compute_csum+0x134/0x220 Read of size 4 at addr ffff88811c50db00 by task iperf3/1691 CPU: 2 PID: 1691 Comm: iperf3 Not tainted 6.5.0-rc3+ #309 [..] kasan_report+0x105/0x140 ip_compute_csum+0x134/0x220 iptunnel_pmtud_build_icmp+0x554/0x1020 skb_tunnel_check_pmtu+0x513/0xb80 vxlan_xmit_one+0x139e/0x2ef0 vxlan_xmit+0x1867/0x2760 dev_hard_start_xmit+0x1ee/0x4f0 br_dev_queue_push_xmit+0x4d1/0x660 [..] ip_compute_csum() cannot deal with nonlinear skbs, so avoid it. After this change, splat is gone and iperf3 is no longer stuck. Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets") Signed-off-by: Florian Westphal Link: https://lore.kernel.org/r/20230803152653.29535-2-fw@strlen.de Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ip_tunnel_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/ip_tunnel_core.c +++ b/net/ipv4/ip_tunnel_core.c @@ -224,7 +224,7 @@ static int iptunnel_pmtud_build_icmp(str .un.frag.__unused = 0, .un.frag.mtu = htons(mtu), }; - icmph->checksum = ip_compute_csum(icmph, len); + icmph->checksum = csum_fold(skb_checksum(skb, 0, len, 0)); skb_reset_transport_header(skb); niph = skb_push(skb, sizeof(*niph));