Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:mptcp: ensure snd_nxt is properly initialized on connectChristoph reported a splat hinting at a corrupted snd_una:  WARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 __mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005  Modules linked in:  CPU: 1 PID: 38 Comm: kworker/1:1 Not tainted 6.9.0-rc1-gbbeac67456c9 #59  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014  Workqueue: events mptcp_worker  RIP: 0010:__mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005  Code: be 06 01 00 00 bf 06 01 00 00 e8 a8 12 e7 fe e9 00 fe ff ff e8    8e 1a e7 fe 0f b7 ab 3e 02 00 00 e9 d3 fd ff ff e8 7d 1a e7 fe         <0f> 0b 4c 8b bb e0 05 00 00 e9 74 fc ff ff e8 6a 1a e7 fe 0f 0b e9  RSP: 0018:ffffc9000013fd48 EFLAGS: 00010293  RAX: 0000000000000000 RBX: ffff8881029bd280 RCX: ffffffff82382fe4  RDX: ffff8881003cbd00 RSI: ffffffff823833c3 RDI: 0000000000000001  RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000  R10: 0000000000000000 R11: fefefefefefefeff R12: ffff888138ba8000  R13: 0000000000000106 R14: ffff8881029bd908 R15: ffff888126560000  FS:  0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033  CR2: 00007f604a5dae38 CR3: 0000000101dac002 CR4: 0000000000170ef0  Call Trace:   <TASK>   __mptcp_clean_una_wakeup net/mptcp/protocol.c:1055 inline]   mptcp_clean_una_wakeup net/mptcp/protocol.c:1062 [inline]   __mptcp_retrans+0x7f/0x7e0 net/mptcp/protocol.c:2615   mptcp_worker+0x434/0x740 net/mptcp/protocol.c:2767   process_one_work+0x1e0/0x560 kernel/workqueue.c:3254   process_scheduled_works kernel/workqueue.c:3335 [inline]   worker_thread+0x3c7/0x640 kernel/workqueue.c:3416   kthread+0x121/0x170 kernel/kthread.c:388   ret_from_fork+0x44/0x50 arch/x86/kernel/process.c:147   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243   </TASK>When fallback to TCP happens early on a client socket, snd_nxtis not yet initialized and any incoming ack will copy such valueinto snd_una. If the mptcp worker (dumbly) tries mptcp-levelre-injection after such ack, that would unconditionally trigger a sendbuffer cleanup using 'bad' snd_una values.We could easily disable re-injection for fallback sockets, but suchdumb behavior already helped catching a few subtle issues and a verylow to zero impact in practice.Instead address the issue always initializing snd_nxt (and write_seq,for consistency) at connect time.

CREATE(Triage):(User=admin) [CVE-2024-36889 (https://nvd.nist.gov/vuln/detail/CVE-2024-36889)

CVEs

• CVE-2024-36889