CVE-2024-36889
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2024-36889
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-36889.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2024-36889
- Downstream
- Related
- Published
- 2024-05-30T15:28:56Z
- Modified
- 2025-10-17T07:24:35.681534Z
- Summary
- mptcp: ensure snd_nxt is properly initialized on connect
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
mptcp: ensure snd_nxt is properly initialized on connect
Christoph reported a splat hinting at a corrupted snd_una:
WARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 mptcpcleanuna+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 mptcpworker RIP: 0010:mptcpcleanuna+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> _mptcpcleanunawakeup net/mptcp/protocol.c:1055 [inline] mptcpcleanunawakeup net/mptcp/protocol.c:1062 [inline] _mptcpretrans+0x7f/0x7e0 net/mptcp/protocol.c:2615 mptcpworker+0x434/0x740 net/mptcp/protocol.c:2767 processonework+0x1e0/0x560 kernel/workqueue.c:3254 processscheduledworks kernel/workqueue.c:3335 [inline] workerthread+0x3c7/0x640 kernel/workqueue.c:3416 kthread+0x121/0x170 kernel/kthread.c:388 retfromfork+0x44/0x50 arch/x86/kernel/process.c:147 retfromforkasm+0x1a/0x30 arch/x86/entry/entry64.S:243 </TASK>
When fallback to TCP happens early on a client socket, sndnxt is not yet initialized and any incoming ack will copy such value into snduna. If the mptcp worker (dumbly) tries mptcp-level re-injection after such ack, that would unconditionally trigger a send buffer cleanup using 'bad' snd_una values.
We could easily disable re-injection for fallback sockets, but such dumb behavior already helped catching a few subtle issues and a very low to zero impact in practice.
Instead address the issue always initializing sndnxt (and writeseq, for consistency) at connect time.
- References
-
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/39ca83ed73db9edcc6d70c0dc7a73085a4725012
- https://git.kernel.org/stable/c/592f69b41766d366dbb8ff4ef5a67c4396527bbe
- https://git.kernel.org/stable/c/99951b62bf20cec9247f633a3bea898338b9e5b4
- https://git.kernel.org/stable/c/aa0c07c1f20e05b30019bff083ec43665536f06f
- https://git.kernel.org/stable/c/dc941fec0719d0471a5902424d6b2a17df233193
- https://git.kernel.org/stable/c/fb7a0d334894206ae35f023a82cad5a290fd7386
- https://lists.debian.org/debian-lts-announce/2024/06/msg00019.html
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8fd738049ac3d67a937d36577763b47180aae1adFixed99951b62bf20cec9247f633a3bea898338b9e5b4
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8fd738049ac3d67a937d36577763b47180aae1adFixeddc941fec0719d0471a5902424d6b2a17df233193
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8fd738049ac3d67a937d36577763b47180aae1adFixed39ca83ed73db9edcc6d70c0dc7a73085a4725012
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8fd738049ac3d67a937d36577763b47180aae1adFixedaa0c07c1f20e05b30019bff083ec43665536f06f
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8fd738049ac3d67a937d36577763b47180aae1adFixed592f69b41766d366dbb8ff4ef5a67c4396527bbe
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8fd738049ac3d67a937d36577763b47180aae1adFixedfb7a0d334894206ae35f023a82cad5a290fd7386