From patchwork Thu Sep 26 16:58:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13813534 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B3B513A24D for ; Thu, 26 Sep 2024 16:58:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727369920; cv=none; b=Ldgr29S22b55Eb0q9YzHhO3rPzgzVqfCSYMqAPujk4OhjkrGTzGn6mWay5KcCEfH4ehOkg256pvjiTWmoS73cLTu22Jeyeja3LbBIfJopxoaKgnBox5z3Gi0SNYERgKeGa+gEGIf34KT+/Y2NpjtGYxZ4ehWVXtJ7LJfvaEqewY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727369920; c=relaxed/simple; bh=fVaxTmB4NV1OCXRKB3OMFq8Iq8+ZzilHjMWGLJ0TWn4=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=uNL5T8vB7Iuj5tPz4Dvbma2lSm0w16CumhJq9E6187bYCK5QIhySe13MnFlYP3DLa+KQsXPs7eDcUR/8TA2fPd5yIYIL7EWceoMYBwuO4rURanEIAtPzPuGfSwvkJILNybzkXzrd5s6HT1oK/jDPqlTh0Uv8HSl06ELouuSayOw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Z5+XV4aY; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Z5+XV4aY" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-e25cba4c68eso1842220276.3 for ; Thu, 26 Sep 2024 09:58:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727369918; x=1727974718; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:from:to:cc:subject:date:message-id:reply-to; bh=GXlUBHTWY+cVrHWhG3FhnsD2YW3smZYGjUjPKSjnIA8=; b=Z5+XV4aYGH833aOiqj3xbpHiCMZBzIH7weEgEhwKNkoV8t8X/1CBxgHdTsh/I8/Lcz wnzJJnDh3QsEspQMXDOYGfPD3W5/jvUxOg6QFR3QWp6SeIJgZXgJCAAHymiBb7qD15D7 MxXzus6Vo/zb7oDf0enN7hDDVo3INy+DirRxaVbPoFySv2WCTQZCP68uLRt+/fi/WJAy fHAC7zz28yv7vFb9O+9i+rbhrDhr6f7n2rvDQ4B5mbrwJ1d5h9mXc2BqlCvo/MpdiEGd mBlqxqWvpk9bxhk/3jAr4mpt9UR1ZwDfDnvAi4ebBxToa+4N/PUhjH3YEZ/Rocv6iKo3 uCyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727369918; x=1727974718; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=GXlUBHTWY+cVrHWhG3FhnsD2YW3smZYGjUjPKSjnIA8=; b=P/M0FwlRKlGkwN3YiFvbHzyQxzlFq4pYGiz/ywmzxbWHOt2gHxZqNK56gFIpvYMBhv UmkL+aHdlM094Cag9TwrXhzRE3yFjJmf7MYwGIReWnDcyNYK318GBe8eHPXbaPqaubt4 H/m6c1+EqT0Yrp+Pf86ms/tmQPLYZ3izV2bNOEDFFs+P/FRJ8N9PF6SZ9XRb2lYEOtTt 8ESGDt2v1h+pOllxURsBN1Aj6Yim7Oy37YpxuUHyLNMxpXNPhB/g1TYh93ZUWVeTzvPw eIuooLafwDI4lwxCxEUsWliMVZ3LFDZ6uB+kTrjsGqwX3uPbGH9d3IysCktZYGGzdczR fqEg== X-Gm-Message-State: AOJu0YyqZuS3gvrMIdny8mkJAfMEGvythVjnY50Vgr84tRaL4B8invqQ 50DrumSqxHSwm0agwJJi3liSn5Zb43N9NLWEcWIFWcLFeicwNy5KVJl4WmSu/MtIGqNSk/Ja2nj VI/J5iganaw== X-Google-Smtp-Source: AGHT+IGbq5iv88FiXTmyKjeMCkr8Qb1ox0yVZ+YbO4rq4frJkBVuVNmyUu/KU7QLea+MyDFR5L0HdJjYvmAGvQ== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:f7:ea0b:ac12:11d6]) (user=edumazet job=sendgmr) by 2002:a5b:a01:0:b0:e02:c06f:1db8 with SMTP id 3f1490d57ef6-e2604b2b153mr40276.4.1727369917869; Thu, 26 Sep 2024 09:58:37 -0700 (PDT) Date: Thu, 26 Sep 2024 16:58:36 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.46.1.824.gd892dcdcdd-goog Message-ID: <20240926165836.3797406-1-edumazet@google.com> Subject: [PATCH net] net: test for not too small csum_start in virtio_net_hdr_to_skb() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, Willem de Bruijn , eric.dumazet@gmail.com, Eric Dumazet X-Patchwork-Delegate: kuba@kernel.org syzbot was able to trigger this warning [1], after injecting a malicious packet through af_packet, setting skb->csum_start and thus the transport header to an incorrect value. We can at least make sure the transport header is after the end of the network header (with a estimated minimal size). [1] [ 67.873027] skb len=4096 headroom=16 headlen=14 tailroom=0 mac=(-1,-1) mac_len=0 net=(16,-6) trans=10 shinfo(txflags=0 nr_frags=1 gso(size=0 type=0 segs=0)) csum(0xa start=10 offset=0 ip_summed=3 complete_sw=0 valid=0 level=0) hash(0x0 sw=0 l4=0) proto=0x0800 pkttype=0 iif=0 priority=0x0 mark=0x0 alloc_cpu=10 vlan_all=0x0 encapsulation=0 inner(proto=0x0000, mac=0, net=0, trans=0) [ 67.877172] dev name=veth0_vlan feat=0x000061164fdd09e9 [ 67.877764] sk family=17 type=3 proto=0 [ 67.878279] skb linear: 00000000: 00 00 10 00 00 00 00 00 0f 00 00 00 08 00 [ 67.879128] skb frag: 00000000: 0e 00 07 00 00 00 28 00 08 80 1c 00 04 00 00 02 [ 67.879877] skb frag: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.880647] skb frag: 00000020: 00 00 02 00 00 00 08 00 1b 00 00 00 00 00 00 00 [ 67.881156] skb frag: 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.881753] skb frag: 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.882173] skb frag: 00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.882790] skb frag: 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883171] skb frag: 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883733] skb frag: 00000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.884206] skb frag: 00000090: 00 00 00 00 00 00 00 00 00 00 69 70 76 6c 61 6e [ 67.884704] skb frag: 000000a0: 31 00 00 00 00 00 00 00 00 00 2b 00 00 00 00 00 [ 67.885139] skb frag: 000000b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.885677] skb frag: 000000c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886042] skb frag: 000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886408] skb frag: 000000e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887020] skb frag: 000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887384] skb frag: 00000100: 00 00 [ 67.887878] ------------[ cut here ]------------ [ 67.887908] offset (-6) >= skb_headlen() (14) [ 67.888445] WARNING: CPU: 10 PID: 2088 at net/core/dev.c:3332 skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.889353] Modules linked in: macsec macvtap macvlan hsr wireguard curve25519_x86_64 libcurve25519_generic libchacha20poly1305 chacha_x86_64 libchacha poly1305_x86_64 dummy bridge sr_mod cdrom evdev pcspkr i2c_piix4 9pnet_virtio 9p 9pnet netfs [ 67.890111] CPU: 10 UID: 0 PID: 2088 Comm: b363492833 Not tainted 6.11.0-virtme #1011 [ 67.890183] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 67.890309] RIP: 0010:skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891043] Call Trace: [ 67.891173] [ 67.891274] ? __warn (kernel/panic.c:741) [ 67.891320] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891333] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 67.891348] ? handle_bug (arch/x86/kernel/traps.c:239) [ 67.891363] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 67.891372] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) [ 67.891388] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891399] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891416] ip_do_fragment (net/ipv4/ip_output.c:777 (discriminator 1)) [ 67.891448] ? __ip_local_out (./include/linux/skbuff.h:1146 ./include/net/l3mdev.h:196 ./include/net/l3mdev.h:213 net/ipv4/ip_output.c:113) [ 67.891459] ? __pfx_ip_finish_output2 (net/ipv4/ip_output.c:200) [ 67.891470] ? ip_route_output_flow (./arch/x86/include/asm/preempt.h:84 (discriminator 13) ./include/linux/rcupdate.h:96 (discriminator 13) ./include/linux/rcupdate.h:871 (discriminator 13) net/ipv4/route.c:2625 (discriminator 13) ./include/net/route.h:141 (discriminator 13) net/ipv4/route.c:2852 (discriminator 13)) [ 67.891484] ipvlan_process_v4_outbound (drivers/net/ipvlan/ipvlan_core.c:445 (discriminator 1)) [ 67.891581] ipvlan_queue_xmit (drivers/net/ipvlan/ipvlan_core.c:542 drivers/net/ipvlan/ipvlan_core.c:604 drivers/net/ipvlan/ipvlan_core.c:670) [ 67.891596] ipvlan_start_xmit (drivers/net/ipvlan/ipvlan_main.c:227) [ 67.891607] dev_hard_start_xmit (./include/linux/netdevice.h:4916 ./include/linux/netdevice.h:4925 net/core/dev.c:3588 net/core/dev.c:3604) [ 67.891620] __dev_queue_xmit (net/core/dev.h:168 (discriminator 25) net/core/dev.c:4425 (discriminator 25)) [ 67.891630] ? skb_copy_bits (./include/linux/uaccess.h:233 (discriminator 1) ./include/linux/uaccess.h:260 (discriminator 1) ./include/linux/highmem-internal.h:230 (discriminator 1) net/core/skbuff.c:3018 (discriminator 1)) [ 67.891645] ? __pskb_pull_tail (net/core/skbuff.c:2848 (discriminator 4)) [ 67.891655] ? skb_partial_csum_set (net/core/skbuff.c:5657) [ 67.891666] ? virtio_net_hdr_to_skb.constprop.0 (./include/linux/skbuff.h:2791 (discriminator 3) ./include/linux/skbuff.h:2799 (discriminator 3) ./include/linux/virtio_net.h:109 (discriminator 3)) [ 67.891684] packet_sendmsg (net/packet/af_packet.c:3145 (discriminator 1) net/packet/af_packet.c:3177 (discriminator 1)) [ 67.891700] ? _raw_spin_lock_bh (./arch/x86/include/asm/atomic.h:107 (discriminator 4) ./include/linux/atomic/atomic-arch-fallback.h:2170 (discriminator 4) ./include/linux/atomic/atomic-instrumented.h:1302 (discriminator 4) ./include/asm-generic/qspinlock.h:111 (discriminator 4) ./include/linux/spinlock.h:187 (discriminator 4) ./include/linux/spinlock_api_smp.h:127 (discriminator 4) kernel/locking/spinlock.c:178 (discriminator 4)) [ 67.891716] __sys_sendto (net/socket.c:730 (discriminator 1) net/socket.c:745 (discriminator 1) net/socket.c:2210 (discriminator 1)) [ 67.891734] ? do_sock_setsockopt (net/socket.c:2335) [ 67.891747] ? __sys_setsockopt (./include/linux/file.h:34 net/socket.c:2355) [ 67.891761] __x64_sys_sendto (net/socket.c:2222 (discriminator 1) net/socket.c:2218 (discriminator 1) net/socket.c:2218 (discriminator 1)) [ 67.891772] do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1) arch/x86/entry/common.c:83 (discriminator 1)) [ 67.891785] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Fixes: 9181d6f8a2bb ("net: add more sanity check in virtio_net_hdr_to_skb()") Signed-off-by: Eric Dumazet --- include/linux/virtio_net.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 276ca543ef44d862d095243073da4fdad88bb889..02a9f4dc594d02372a6c1850cd600eff9d000d8d 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -103,8 +103,10 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, if (!skb_partial_csum_set(skb, start, off)) return -EINVAL; + if (skb_transport_offset(skb) < nh_min_len) + return -EINVAL; - nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb)); + nh_min_len = skb_transport_offset(skb); p_off = nh_min_len + thlen; if (!pskb_may_pull(skb, p_off)) return -EINVAL;