CVE-2024-36889

CVE Details

Release Date:

2024-05-30

Description

In the Linux kernel, the following vulnerability has been resolved:\nmptcp: ensure snd_nxt is properly initialized on connect\nChristoph reported a splat hinting at a corrupted snd_una:\nWARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 __mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005\nModules linked in:\nCPU: 1 PID: 38 Comm: kworker/1:1 Not tainted 6.9.0-rc1-gbbeac67456c9 #59\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014\nWorkqueue: events mptcp_worker\nRIP: 0010:__mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005\nCode: be 06 01 00 00 bf 06 01 00 00 e8 a8 12 e7 fe e9 00 fe ff ff e8\n8e 1a e7 fe 0f b7 ab 3e 02 00 00 e9 d3 fd ff ff e8 7d 1a e7 fe\n<0f> 0b 4c 8b bb e0 05 00 00 e9 74 fc ff ff e8 6a 1a e7 fe 0f 0b e9\nRSP: 0018:ffffc9000013fd48 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffff8881029bd280 RCX: ffffffff82382fe4\nRDX: ffff8881003cbd00 RSI: ffffffff823833c3 RDI: 0000000000000001\nRBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000\nR10: 0000000000000000 R11: fefefefefefefeff R12: ffff888138ba8000\nR13: 0000000000000106 R14: ffff8881029bd908 R15: ffff888126560000\nFS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f604a5dae38 CR3: 0000000101dac002 CR4: 0000000000170ef0\nCall Trace:\n\n__mptcp_clean_una_wakeup net/mptcp/protocol.c:1055 [inline]\nmptcp_clean_una_wakeup net/mptcp/protocol.c:1062 [inline]\n__mptcp_retrans+0x7f/0x7e0 net/mptcp/protocol.c:2615\nmptcp_worker+0x434/0x740 net/mptcp/protocol.c:2767\nprocess_one_work+0x1e0/0x560 kernel/workqueue.c:3254\nprocess_scheduled_works kernel/workqueue.c:3335 [inline]\nworker_thread+0x3c7/0x640 kernel/workqueue.c:3416\nkthread+0x121/0x170 kernel/kthread.c:388\nret_from_fork+0x44/0x50 arch/x86/kernel/process.c:147\nret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243\n\nWhen fallback to TCP happens early on a client socket, snd_nxt\nis not yet initialized and any incoming ack will copy such value\ninto snd_una. If the mptcp worker (dumbly) tries mptcp-level\nre-injection after such ack, that would unconditionally trigger a send\nbuffer cleanup using 'bad' snd_una values.\nWe could easily disable re-injection for fallback sockets, but such\ndumb behavior already helped catching a few subtle issues and a very\nlow to zero impact in practice.\nInstead address the issue always initializing snd_nxt (and write_seq,\nfor consistency) at connect time.

See more information about CVE-2024-36889 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	5.5	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (kernel)	ELSA-2024-5101	2024-08-08
Oracle Linux version 9 (kernel)	ELSA-2024-8162	2024-10-16