CVE-2024-36889
Vulnerability Summary
Timeline
Description
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 __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_nxt is not yet initialized and any incoming ack will copy such value into snd_una. 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 snd_nxt (and write_seq, for consistency) at connect time.
CVSS Metrics
- v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Trends
Current EPSS score: 0.27%• Percentile: 19%
Affected Systems
- debian•linux
< 5.10.218-1 | < 6.1.94-1 | < 6.8.11-1 | < 6.8.11-1
- ubuntu•linux
< 5.15.0-118.128 | < 6.8.0-40.40
- ubuntu•linux-allwinner-5.19
all
- ubuntu•linux-aws
< 5.15.0-1067.73 | < 6.8.0-1013.14
- ubuntu•linux-aws-5.0
all
- ubuntu•linux-aws-5.11
all
- ubuntu•linux-aws-5.13
all
- ubuntu•linux-aws-5.15
< 5.15.0-1067.73~20.04.1
- ubuntu•linux-aws-5.19
all
- ubuntu•linux-aws-5.3
all
- ubuntu•linux-aws-5.8
all
- ubuntu•linux-aws-6.2
all
- ubuntu•linux-aws-6.5
all
- ubuntu•linux-aws-6.8
< 6.8.0-1013.14~22.04.1
- ubuntu•linux-aws-fips
all | < 5.15.0-1067.73+fips1
- ubuntu•linux-azure
all | < 5.15.0-1070.79 | < 6.8.0-1012.14
- ubuntu•linux-azure-5.11
all
- ubuntu•linux-azure-5.13
all
- ubuntu•linux-azure-5.15
< 5.15.0-1070.79~20.04.1
- ubuntu•linux-azure-5.19
all
- ubuntu•linux-azure-5.3
all
- ubuntu•linux-azure-5.8
all
- ubuntu•linux-azure-6.2
all
- ubuntu•linux-azure-6.5
all
- ubuntu•linux-azure-6.8
< 6.8.0-1012.14~22.04.1
- ubuntu•linux-azure-edge
all
- ubuntu•linux-azure-fde
all | < 5.15.0-1070.79.1
- ubuntu•linux-azure-fde-5.19
all
- ubuntu•linux-azure-fde-6.2
all
- ubuntu•linux-azure-fips
all | < 5.15.0-1070.79+fips1
- ubuntu•linux-bluefield
all | < 5.15.0-1050.52
- ubuntu•linux-fips
all | < 5.15.0-118.128+fips1 | < 6.8.0-78.78+fips1
- ubuntu•linux-gcp
all | < 5.15.0-1066.74 | < 6.8.0-1012.13
- ubuntu•linux-gcp-5.11
all
- ubuntu•linux-gcp-5.13
all
- ubuntu•linux-gcp-5.15
< 5.15.0-1066.74~20.04.1
- ubuntu•linux-gcp-5.19
all
- ubuntu•linux-gcp-5.3
all
- ubuntu•linux-gcp-5.8
all
- ubuntu•linux-gcp-6.2
all
- ubuntu•linux-gcp-6.5
all
- ubuntu•linux-gcp-6.8
< 6.8.0-1012.13~22.04.1
- ubuntu•linux-gcp-fips
all | < 5.15.0-1066.74+fips1
- ubuntu•linux-gke
all | < 5.15.0-1064.70 | < 6.8.0-1008.11
- ubuntu•linux-gke-4.15
all
- ubuntu•linux-gke-5.15
all
- ubuntu•linux-gke-5.4
all
- ubuntu•linux-gkeop
< 5.15.0-1050.57
- ubuntu•linux-gkeop-5.15
< 5.15.0-1050.57~20.04.1
- ubuntu•linux-gkeop-5.4
all
Showing first 50 affected entries in server-rendered view.
References (23)
- https://git.kernel.org/stable/c/99951b62bf20cec9247f633a3bea898338b9e5b4
- https://git.kernel.org/stable/c/dc941fec0719d0471a5902424d6b2a17df233193
- https://git.kernel.org/stable/c/39ca83ed73db9edcc6d70c0dc7a73085a4725012
- https://git.kernel.org/stable/c/aa0c07c1f20e05b30019bff083ec43665536f06f
- https://git.kernel.org/stable/c/592f69b41766d366dbb8ff4ef5a67c4396527bbe
- https://git.kernel.org/stable/c/fb7a0d334894206ae35f023a82cad5a290fd7386
- https://lists.debian.org/debian-lts-announce/2024/06/msg00019.html
- https://ubuntu.com/security/CVE-2024-36889
- https://www.cve.org/CVERecord?id=CVE-2024-36889
- https://git.kernel.org/linus/fb7a0d334894206ae35f023a82cad5a290fd7386
- https://ubuntu.com/security/notices/USN-6949-1
- https://ubuntu.com/security/notices/USN-6950-1
- https://ubuntu.com/security/notices/USN-6952-1
- https://ubuntu.com/security/notices/USN-6955-1
- https://ubuntu.com/security/notices/USN-6956-1
- https://ubuntu.com/security/notices/USN-6957-1
- https://ubuntu.com/security/notices/USN-6950-2
- https://ubuntu.com/security/notices/USN-6950-3
- https://ubuntu.com/security/notices/USN-6949-2
- https://ubuntu.com/security/notices/USN-6952-2
- https://ubuntu.com/security/notices/USN-6950-4
- https://ubuntu.com/security/notices/USN-7019-1
- https://security-tracker.debian.org/tracker/CVE-2024-36889