From patchwork Tue May 31 18:59:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 12866035 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 438E2C433EF for ; Tue, 31 May 2022 18:59:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347209AbiEaS7m (ORCPT ); Tue, 31 May 2022 14:59:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236089AbiEaS7k (ORCPT ); Tue, 31 May 2022 14:59:40 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A41E756C13 for ; Tue, 31 May 2022 11:59:39 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id o6-20020a17090a0a0600b001e2c6566046so3772209pjo.0 for ; Tue, 31 May 2022 11:59:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=EPjRtCzpcwhsp0aa03Ct4d3QKHS7Y4VNiM26sMhWi4U=; b=QqfqHg8wheuian0etd6tXWyZ95h2vdLJiIAdCNS2RdIuT313AKIbqjbE1GqcYCWCG7 xGlqWsutkOel+bDaPwziTy4Hjs/GbTBxtHeybbJ8XOEAOwykHuicFOVtso22Lf3XTCxc wf7G69XSSgKgsuSb8PCY1Kxx5dt17ZZkYd6SZKXSdLI3CxbeyFq15D/3J5h6G/1qwY4d 4fpuJDY39PxXA6BT1P7U6T0v0oeZe8y3YPO1V7oVSLVMlBhs/ZhQSfaGEUx2DM1q3+pL 4jNz+KCOqchy3y4ziAJSVl/PDMbAWD7ELnwHUtZdcUW+j7ExBGUC6OyQb49ynB0WKDef A4Jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=EPjRtCzpcwhsp0aa03Ct4d3QKHS7Y4VNiM26sMhWi4U=; b=O1Ut+AHDTN9PgSoQL5O1XROPKVTrBlKTMxUlH0WZy5/7wdN9eLAZDrLHgxRGz9JSUh nO97kdswIXqQKRC7utSj/35sokEjytTCShG2c4lj49ngBdEdJq0A9Om1UvPFFPFkkJSu lt9IPyP8qkcKGnuYgeoWzVC0C4J74KJGNPIGUpEsBW04ccztbpCfcKW5b335hMyvNfvu pY10HG7RshQqcttI/2wt+hGL6Eu2qnoXri9cEktGrzg9Leks3J1JZPEdzTXYmcAKMrKr cvuBWJzkGq3aefFeW87URJ+o+p7B+1cBAjtfgA3QjtWYvgYvCHoSpmdLD5m6mqxCJ2ud D6rw== X-Gm-Message-State: AOAM533gIqwuiJXwIODfKDzg8qym26vm6khVG2JKXeSVackut3uviUjD 6TIjs1q+siuRSZ1izGF2ys/0fV/3pkY= X-Google-Smtp-Source: ABdhPJwExUNTG/8IdDeERo9ED5rwYwC6WY57Phap0Bwajm4dRrl5OpzvNXmDlxCmgyl/Q7OveUHq6A== X-Received: by 2002:a17:90a:778c:b0:1df:56a5:8474 with SMTP id v12-20020a17090a778c00b001df56a58474mr30263294pjk.63.1654023579108; Tue, 31 May 2022 11:59:39 -0700 (PDT) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:74f8:d874:7d9d:dabb]) by smtp.gmail.com with ESMTPSA id y30-20020a056a001c9e00b0050dc762814dsm10941628pfw.39.2022.05.31.11.59.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 May 2022 11:59:38 -0700 (PDT) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev , Willem de Bruijn , Eric Dumazet , Eric Dumazet Subject: [PATCH net 1/2] net: add debug info to __skb_pull() Date: Tue, 31 May 2022 11:59:32 -0700 Message-Id: <20220531185933.1086667-2-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.36.1.255.ge46751e96f-goog In-Reply-To: <20220531185933.1086667-1-eric.dumazet@gmail.com> References: <20220531185933.1086667-1-eric.dumazet@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Eric Dumazet While analyzing yet another syzbot report, I found the following patch very useful. It allows to better understand what went wrong. This debug info is only enabled if CONFIG_DEBUG_NET=y, which is the case for syzbot builds. Signed-off-by: Eric Dumazet Acked-by: Willem de Bruijn Reported-by: kernel test robot Reported-by: kernel test robot --- include/linux/skbuff.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index da96f0d3e753fb7996631bc9350c0c8e0ec5966e..d3d10556f0faea8c8c1deed5715716d4916011d1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2696,7 +2696,14 @@ void *skb_pull(struct sk_buff *skb, unsigned int len); static inline void *__skb_pull(struct sk_buff *skb, unsigned int len) { skb->len -= len; - BUG_ON(skb->len < skb->data_len); + if (unlikely(skb->len < skb->data_len)) { +#if defined(CONFIG_DEBUG_NET) + skb->len += len; + pr_err("__skb_pull(len=%u)\n", len); + skb_dump(KERN_ERR, skb, false); +#endif + BUG(); + } return skb->data += len; } From patchwork Tue May 31 18:59:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 12866036 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32597C433EF for ; Tue, 31 May 2022 18:59:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236089AbiEaS7r (ORCPT ); Tue, 31 May 2022 14:59:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347210AbiEaS7m (ORCPT ); Tue, 31 May 2022 14:59:42 -0400 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FEA398089 for ; Tue, 31 May 2022 11:59:41 -0700 (PDT) Received: by mail-pj1-x102f.google.com with SMTP id u12-20020a17090a1d4c00b001df78c7c209so3749398pju.1 for ; Tue, 31 May 2022 11:59:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=cNiGCPoi6p1OejqRoSXTe2BoMHzWdsim8KjMuMoTcjQ=; b=EavEoA2pkqMMLG8GUY4cXqgCClF1i+mDuRrHH/zvGcwnEGLHsabsSJdH86XwqFVQtl HR0ak9hK8xityx1lT49hYw0sIa+/zU+gi5BQeNgGJunhOMNBTiwucUM/Ay1hYVY1dr8p l0knbIapWyr8lvfEx5BgqRwIuG8XTIl+yHSAs94HRaWYus/s9iKFDSNJmR7OWAEbrt+V moVA4SnrD7gnnuocqar2B6zRcWkGH/Nn+b1zAxyZ8SduOOla1vokcbftFBl2xIK2KQEc AGWHjwRAsUZQ2R67RHQKWac2FDxgkRNh7VczvlM6tlaiQ33mikyq1lQ35En0Cm4YHqXd 1pPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=cNiGCPoi6p1OejqRoSXTe2BoMHzWdsim8KjMuMoTcjQ=; b=GxN9eSEb7Z5TAg/uSMIaJcAdpVp+hUhn7U6bBVcs+xcJ5L3poX5eoTa2a268/+u3hh q/7H2plgc1CuNSwaSWt8npCIeoVDJ6kqtcWxLF07tZRDjoP9Qm06uVNZLp7Hls7bXdOa G50V9b73RAtsAfjpKLlHcmvvpQi6QgXHObz8dV06p5HfiI/YxuDc89sFRHJT0bRxv/5Q pWqrN4JdKDYzf2eeMr4dRDtb1m3IWAXjl2JClUnOmyVLbBb/ns54OHgvgLsc8rJdUdNu kuRtE1Gv+2MndmYQ9tyRI50CPjEIZ+RaR2Z7d9kjd1PHOsCI4JV0HbPJer0MyVLKJ0q4 BDJg== X-Gm-Message-State: AOAM5313nCfsZOTDoMhPDfGNnBdqWFETyvsJBlEIyPRx05CnP5D+FNBP mooGwXrhaIf3T4F2pkBDsLc= X-Google-Smtp-Source: ABdhPJzKJjNFlEgXlVCNbqo+Y3LI8SW5W66RsZ70ii8zBnHKWFTFl7woQhqrVGK6aTMgnv3H0TWknA== X-Received: by 2002:a17:902:e945:b0:15f:22cd:c6cc with SMTP id b5-20020a170902e94500b0015f22cdc6ccmr63580999pll.162.1654023580823; Tue, 31 May 2022 11:59:40 -0700 (PDT) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:74f8:d874:7d9d:dabb]) by smtp.gmail.com with ESMTPSA id y30-20020a056a001c9e00b0050dc762814dsm10941628pfw.39.2022.05.31.11.59.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 May 2022 11:59:40 -0700 (PDT) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev , Willem de Bruijn , Eric Dumazet , Eric Dumazet , syzbot , Hangbin Liu , "Michael S . Tsirkin" Subject: [PATCH net 2/2] net/af_packet: make sure to pull mac header Date: Tue, 31 May 2022 11:59:33 -0700 Message-Id: <20220531185933.1086667-3-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.36.1.255.ge46751e96f-goog In-Reply-To: <20220531185933.1086667-1-eric.dumazet@gmail.com> References: <20220531185933.1086667-1-eric.dumazet@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Eric Dumazet GSO assumes skb->head contains link layer headers. tun device in some case can provide base 14 bytes, regardless of VLAN being used or not. After blamed commit, we can end up setting a network header offset of 18+, we better pull the missing bytes to avoid a posible crash in GSO. syzbot report was: kernel BUG at include/linux/skbuff.h:2699! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 3601 Comm: syz-executor210 Not tainted 5.18.0-syzkaller-11338-g2c5ca23f7414 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__skb_pull include/linux/skbuff.h:2699 [inline] RIP: 0010:skb_mac_gso_segment+0x48f/0x530 net/core/gro.c:136 Code: 00 48 c7 c7 00 96 d4 8a c6 05 cb d3 45 06 01 e8 26 bb d0 01 e9 2f fd ff ff 49 c7 c4 ea ff ff ff e9 f1 fe ff ff e8 91 84 19 fa <0f> 0b 48 89 df e8 97 44 66 fa e9 7f fd ff ff e8 ad 44 66 fa e9 48 RSP: 0018:ffffc90002e2f4b8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000012 RCX: 0000000000000000 RDX: ffff88805bb58000 RSI: ffffffff8760ed0f RDI: 0000000000000004 RBP: 0000000000005dbc R08: 0000000000000004 R09: 0000000000000fe0 R10: 0000000000000fe4 R11: 0000000000000000 R12: 0000000000000fe0 R13: ffff88807194d780 R14: 1ffff920005c5e9b R15: 0000000000000012 FS: 000055555730f300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200015c0 CR3: 0000000071ff8000 CR4: 0000000000350ee0 Call Trace: __skb_gso_segment+0x327/0x6e0 net/core/dev.c:3411 skb_gso_segment include/linux/netdevice.h:4749 [inline] validate_xmit_skb+0x6bc/0xf10 net/core/dev.c:3669 validate_xmit_skb_list+0xbc/0x120 net/core/dev.c:3719 sch_direct_xmit+0x3d1/0xbe0 net/sched/sch_generic.c:327 __dev_xmit_skb net/core/dev.c:3815 [inline] __dev_queue_xmit+0x14a1/0x3a00 net/core/dev.c:4219 packet_snd net/packet/af_packet.c:3071 [inline] packet_sendmsg+0x21cb/0x5550 net/packet/af_packet.c:3102 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:734 ____sys_sendmsg+0x6eb/0x810 net/socket.c:2492 ___sys_sendmsg+0xf3/0x170 net/socket.c:2546 __sys_sendmsg net/socket.c:2575 [inline] __do_sys_sendmsg net/socket.c:2584 [inline] __se_sys_sendmsg net/socket.c:2582 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2582 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f4b95da06c9 Code: 28 c3 e8 4a 15 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd7defc4c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ffd7defc4f0 RCX: 00007f4b95da06c9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 0000000000000003 R08: bb1414ac00000050 R09: bb1414ac00000050 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd7defc4e0 R14: 00007ffd7defc4d8 R15: 00007ffd7defc4d4 Fixes: dfed913e8b55 ("net/af_packet: add VLAN support for AF_PACKET SOCK_RAW GSO") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Hangbin Liu Cc: Willem de Bruijn Cc: Michael S. Tsirkin Acked-by: Willem de Bruijn Acked-by: Hangbin Liu --- net/packet/af_packet.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 677f9cfa9660816a160a11bfa4c291431412005f..ca6e92a229239f9093900bf9249396cf0d410104 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1935,8 +1935,10 @@ static void packet_parse_headers(struct sk_buff *skb, struct socket *sock) /* Move network header to the right position for VLAN tagged packets */ if (likely(skb->dev->type == ARPHRD_ETHER) && eth_type_vlan(skb->protocol) && - __vlan_get_protocol(skb, skb->protocol, &depth) != 0) - skb_set_network_header(skb, depth); + __vlan_get_protocol(skb, skb->protocol, &depth) != 0) { + if (pskb_may_pull(skb, depth)) + skb_set_network_header(skb, depth); + } skb_probe_transport_header(skb); }