From patchwork Fri Oct 18 17:36:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthieu Baerts X-Patchwork-Id: 13842096 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 342D22022D6; Fri, 18 Oct 2024 17:37:03 +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=1729273024; cv=none; b=Qgn53wwL5QeIplz5RdCWzGKrUgjfOIzPci0XpgHMRVzUX6x9BsGRUW8vZdHo4P7nEuqHo0cAEL5ls6IGjmz6Abwiug//cbscJzXwacxr7JEbLxiskPqiCQWpLRHkvibU9Es8qbKJyAIIwcHUXe/WyKy4qniaZ3tKM+8MFhnJjE8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729273024; c=relaxed/simple; bh=RSrTbfgfiEGVpf4xw9lIX7c7tf5aEINM1hgGOILLrio=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mYUQrGJZZFQ5hhgEJFFcfcgZ3ikBrxZ3VhSIfPcRsS4BkMDzqJoVPCd2Sj3PEmwMz9OSlVp8tnPMFM3KMmwRONk8wnnDWjMLptYSY2iI7kQ4LvCclg9qbT+qsnnTNKJaNMSXWiWoEhAnlCx0Gn6OheUNcmqVFWAEsyxresYM4aY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HRjKZEQT; 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="HRjKZEQT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F167DC4CEC5; Fri, 18 Oct 2024 17:37:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729273023; bh=RSrTbfgfiEGVpf4xw9lIX7c7tf5aEINM1hgGOILLrio=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HRjKZEQTTelgfoIm6p1wlDYvAHztF+KDLzb7OACyW4Y2XxwBMF3eR9xgc+10ZICVp lkkItUuW3MaWQqnn2+Z+ZpEBxjvxlIlRclL6E+eByy5aCQymaD0zLBQu5Hto8adrTb yQdvoMB6a0n3PW0fIG4h4T0bN9Ur0Gnu3gJNfB3sbCYWFH9gB9oHP7CKNXOav7LNG9 dZgR5auuMfVN7fxAiFg+HABGG1I+wSJVpTHgS5/YL/cNE2h5740ZAf51H1/Zc/kdL8 RyNe4LZ45rXALRPzkUd31FAck4n5DUK5yOIGVkJewi2gkndGAvJEN/mqf/FOMCNObd CMyZ0287TIECg== 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 6.1.y 1/2] tcp: fix mptcp DSS corruption due to large pmtu xmit Date: Fri, 18 Oct 2024 19:36:58 +0200 Message-ID: <20241018173656.2813913-5-matttbe@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241018173656.2813913-4-matttbe@kernel.org> References: <20241018173656.2813913-4-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=C6Je/qgsfW9i/TK6d9fttdemKaxZwb2F+OI9ukvQQD0=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBnEpy4wScYTPV/HoLulYaxfPc8kC+Kpu97LnxPD x9Oz45CeWaJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZxKcuAAKCRD2t4JPQmmg c2kiD/9qxMvdGsVUO3G07d614WO6KKMZy/D6S8OEqf3T+aV/dDOo3Q+Dww+MCiL8BHUgcW6qr5G oLVavHE7AaKflJT3j27nSLn9qnTtIwg3RutmTp0wz4fvSReCKFGgbdWllEdYaHrz5rZ+vxnqI93 /bCq98l/jpjuWZCgEgg1iVNtQnTWJ+XPlzn3GucegCOHpdkDa3gXJ+BogW2plXbExbDPsodgGiQ HbIZkaNIi61ST0zHMpB05ifWB5Ob026DRghblwIG5fzHuVs/dEci/PgRktDj335ST61MwZ5GD27 vFA5gl5jwI6Ip8uJ2I1OeciE1eLFQBBFqRPDImkOW5EzEmEyMAWtvhbYs6UvW1dTxXJL3+O8ZY2 HN6kTmUXo2OKWL8zEOv4AApcMvCUvpOb2Btt8HuD3Z3fEjfy370hjvrbLLL29Z7DvIXDSK5GZDp 3mwuTngyUxan1DxFuarEJb3I61FrQu2liN2NhfqCLDUg5xdZ1dzYKUVKQ+IJumkZhtWlalafkWL ombHRAQkWAOfSjTgbyo8Aer4ARLF4bmN+YFS5CEgQ0zkjIPbAM7kpzKYevvKlareTGfljT5Mf6u Zy91MoRfYrcHSj1ff4HllaFLdxN8sM85HN9eUet0EvVZ2g2h+u/O+qoceT0gBs0aSgRtoTiWKZG XUhLy/1ATwgJ8hQ== 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 19b5a6179c06..3f54b76bc281 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2312,9 +2312,7 @@ 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;