From patchwork Fri Oct 18 15:57:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Matthieu Baerts (NGI0)" X-Patchwork-Id: 13841997 X-Patchwork-Delegate: matthieu.baerts@tessares.net 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 84B48165EFC; Fri, 18 Oct 2024 15:57:44 +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=1729267064; cv=none; b=LNkut2UyEbd7Ht5sCYuyURlUBmcrz3YpeD927GthTdLyPQDEbD5XlqaeBlFog2PezB1Jy64L1NkJKW6zvBfx6Ml1fhEG8G4FF5I26+85EX07oBQlESrHdiOqM1a0m62t4fpKgPCGysYC2ujhj6cZMzobDOVWBxsD7gee7LxV9l4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729267064; c=relaxed/simple; bh=hgmCfXN7zb5NM42rp2ri8PhqNTuLoEUfBsDo6ywwaY4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NyrkhPkwP5Id4oXChBizFmzngb55EFeYwTC6dWnFHRHwXCWT+djGqbtYkR6mxEx+5EcGM9U4OwJnT4wqKKc40CDR+HpkYwg4uFctO+/YS3ZYomJc1cA7QSan2trZp1l98Wt6rhneVMYMlnOOaQuqv0u/eEwYnuNm5farPKsadJM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ThJbuAkM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ThJbuAkM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CAC1C4CED1; Fri, 18 Oct 2024 15:57:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729267064; bh=hgmCfXN7zb5NM42rp2ri8PhqNTuLoEUfBsDo6ywwaY4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ThJbuAkMdXZmD7oj92M7pSpzR9aXh0gonD6rCf24G1G2I2rif4osRTg3ok/wG+OK4 /KljU8aRvPyKZAUHqGmud25Oss2ElOzOCDsTl5ot4wmi5/vt9OymXOg7LMrdB/Wgl7 rihC4iuJQW1ii6NAQnifsB9u4jcl7SF4tEal6X6OoXgmdPhgpMidIJaEL2LO9FqUb0 3gjGfgJqHl4PlqS30kWW+6kvf4bHoflilEXC/S18i6QpVdqGfJ8jDfKvVBhJpk11jZ Ks331XpktPkli4L+jlK9glI27HRFO3VohxJeaXSDISGX+4ELQ4gMbPWGP335FRUPHp CW44bsfKokwbQ== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, syzbot+d1bff73460e33101f0e7@syzkaller.appspotmail.com, Matthieu Baerts , Jakub Kicinski Subject: [PATCH 6.6.y 1/4] tcp: fix mptcp DSS corruption due to large pmtu xmit Date: Fri, 18 Oct 2024 17:57:36 +0200 Message-ID: <20241018155734.2548697-7-matttbe@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241018155734.2548697-6-matttbe@kernel.org> References: <20241018155734.2548697-6-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7325; i=matttbe@kernel.org; h=from:subject; bh=FYrV7BRn2lHPNOR5tk2DVS3bwyeq6k5KQxj8xkI0QL0=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBnEoVuOU4seWKM5unCSEKZQZOn+/Yj3MQr+nWP5 3yjpDhvx76JAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZxKFbgAKCRD2t4JPQmmg c/RMD/9D8c/HBnJinZ7qvF0IABHAlKKHPUsL+DdkJtnWKbV3CifH/KEUzdEG1NfcS+jOLaC85sD qOY8eQXF1k9UvqK4AS5ukZWjtEsqTk3IlvmWjcsClaSgKs+52T29LqAd3ULLU6Lkc4jsI9r71tJ RS9raT1c5UVoCWgvrd42PadnguA37dTDy3BaXfqbLtJ0ImH2oNXHkhhIoBmwZSVJFkGMSygPvEm g43CP5E3/JABek+M2776zyjKECJXUN0x82uFgNMyVUpX9phB78TWEeyLEWBntUUv6dzIjlJUEQg mv44DgmpwClACeTLEoyn5auUiPFqj/da1fD9s+7wpGH0L4Cv7+b8uCkp3wH4yfqwAylAGrGqx6f vBrmwO8vOruw/aena3hlVBPJUAndG5dG/8kt2GfFXrJIwUqk8gjJrWr+BK3c7y4lvekobxSOWeL pA3DquRw+ZnQk9RUgPTEtoXHwXgeoaY9Vy0ENSlrdtLeLw+sjIZKDDszRknF/D8mEKILLdIfzl7 MakGynVBu2KGtWnpsll/CF+GJsuAdcxCm6aeuZgOk3gw+/pTm/7RCHIrTsYz5f93Gmg3KPUumSG YoWLisSOFPAF48FONFWH/hNgSKKsTpn82qRtmyDSlbahv5/4SMYxEJnkChVFjdPpY23OqxWcheA Y1FrtM14VutZrEA== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Paolo Abeni commit 4dabcdf581217e60690467a37c956a5b8dbc6bd9 upstream. Syzkaller was able to trigger a DSS corruption: TCP: request_sock_subflow_v4: Possible SYN flooding on port [::]:20002. Sending cookies. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 5227 at net/mptcp/protocol.c:695 __mptcp_move_skbs_from_subflow+0x20a9/0x21f0 net/mptcp/protocol.c:695 Modules linked in: CPU: 0 UID: 0 PID: 5227 Comm: syz-executor350 Not tainted 6.11.0-syzkaller-08829-gaf9c191ac2a0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:__mptcp_move_skbs_from_subflow+0x20a9/0x21f0 net/mptcp/protocol.c:695 Code: 0f b6 dc 31 ff 89 de e8 b5 dd ea f5 89 d8 48 81 c4 50 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 98 da ea f5 90 <0f> 0b 90 e9 47 ff ff ff e8 8a da ea f5 90 0f 0b 90 e9 99 e0 ff ff RSP: 0018:ffffc90000006db8 EFLAGS: 00010246 RAX: ffffffff8ba9df18 RBX: 00000000000055f0 RCX: ffff888030023c00 RDX: 0000000000000100 RSI: 00000000000081e5 RDI: 00000000000055f0 RBP: 1ffff110062bf1ae R08: ffffffff8ba9cf12 R09: 1ffff110062bf1b8 R10: dffffc0000000000 R11: ffffed10062bf1b9 R12: 0000000000000000 R13: dffffc0000000000 R14: 00000000700cec61 R15: 00000000000081e5 FS: 000055556679c380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020287000 CR3: 0000000077892000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: move_skbs_to_msk net/mptcp/protocol.c:811 [inline] mptcp_data_ready+0x29c/0xa90 net/mptcp/protocol.c:854 subflow_data_ready+0x34a/0x920 net/mptcp/subflow.c:1490 tcp_data_queue+0x20fd/0x76c0 net/ipv4/tcp_input.c:5283 tcp_rcv_established+0xfba/0x2020 net/ipv4/tcp_input.c:6237 tcp_v4_do_rcv+0x96d/0xc70 net/ipv4/tcp_ipv4.c:1915 tcp_v4_rcv+0x2dc0/0x37f0 net/ipv4/tcp_ipv4.c:2350 ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5662 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6107 __napi_poll+0xcb/0x490 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6962 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x1764/0x3e80 net/core/dev.c:4451 dev_queue_xmit include/linux/netdevice.h:3094 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236 ip_local_out net/ipv4/ip_output.c:130 [inline] __ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:536 __tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466 tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline] tcp_mtu_probe net/ipv4/tcp_output.c:2547 [inline] tcp_write_xmit+0x641d/0x6bf0 net/ipv4/tcp_output.c:2752 __tcp_push_pending_frames+0x9b/0x360 net/ipv4/tcp_output.c:3015 tcp_push_pending_frames include/net/tcp.h:2107 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5714 [inline] tcp_rcv_established+0x1026/0x2020 net/ipv4/tcp_input.c:6239 tcp_v4_do_rcv+0x96d/0xc70 net/ipv4/tcp_ipv4.c:1915 sk_backlog_rcv include/net/sock.h:1113 [inline] __release_sock+0x214/0x350 net/core/sock.c:3072 release_sock+0x61/0x1f0 net/core/sock.c:3626 mptcp_push_release net/mptcp/protocol.c:1486 [inline] __mptcp_push_pending+0x6b5/0x9f0 net/mptcp/protocol.c:1625 mptcp_sendmsg+0x10bb/0x1b10 net/mptcp/protocol.c:1903 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2603 ___sys_sendmsg net/socket.c:2657 [inline] __sys_sendmsg+0x2aa/0x390 net/socket.c:2686 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb06e9317f9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe2cfd4f98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb06e97f468 RCX: 00007fb06e9317f9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000005 RBP: 00007fb06e97f446 R08: 0000555500000000 R09: 0000555500000000 R10: 0000555500000000 R11: 0000000000000246 R12: 00007fb06e97f406 R13: 0000000000000001 R14: 00007ffe2cfd4fe0 R15: 0000000000000003 Additionally syzkaller provided a nice reproducer. The repro enables pmtu on the loopback device, leading to tcp_mtu_probe() generating very large probe packets. tcp_can_coalesce_send_queue_head() currently does not check for mptcp-level invariants, and allowed the creation of cross-DSS probes, leading to the mentioned corruption. Address the issue teaching tcp_can_coalesce_send_queue_head() about mptcp using the tcp_skb_can_collapse(), also reducing the code duplication. Fixes: 85712484110d ("tcp: coalesce/collapse must respect MPTCP extensions") Cc: stable@vger.kernel.org Reported-by: syzbot+d1bff73460e33101f0e7@syzkaller.appspotmail.com Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/513 Signed-off-by: Paolo Abeni Acked-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20241008-net-mptcp-fallback-fixes-v1-2-c6fb8e93e551@kernel.org Signed-off-by: Jakub Kicinski [ Conflict in tcp_output.c, because the commit 65249feb6b3d ("net: add support for skbs with unreadable frags") is not in this version. This commit is linked to a new feature (Devmem TCP) and introduces a new condition which causes the conflicts. Resolving this is easy: we can ignore the missing new condition, and use tcp_skb_can_collapse() like in the original patch. ] Signed-off-by: Matthieu Baerts (NGI0) --- net/ipv4/tcp_output.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 15c49d559db5..328640d9b607 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2314,9 +2314,7 @@ static bool tcp_can_coalesce_send_queue_head(struct sock *sk, int len) if (len <= skb->len) break; - if (unlikely(TCP_SKB_CB(skb)->eor) || - tcp_has_tx_tstamp(skb) || - !skb_pure_zcopy_same(skb, next)) + if (tcp_has_tx_tstamp(skb) || !tcp_skb_can_collapse(skb, next)) return false; len -= skb->len;