vulnerability

Ubuntu: (Multiple Advisories) (CVE-2024-36889): Linux kernel vulnerabilities

Severity
5
CVSS
(AV:L/AC:L/Au:S/C:N/I:N/A:C)
Published
05/30/2024
Added
08/09/2024
Modified
02/20/2025

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
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:

__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


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.

Solution(s)

ubuntu-upgrade-linux-image-5-15-0-1035-xilinx-zynqmpubuntu-upgrade-linux-image-5-15-0-1050-gkeopubuntu-upgrade-linux-image-5-15-0-1060-ibmubuntu-upgrade-linux-image-5-15-0-1060-raspiubuntu-upgrade-linux-image-5-15-0-1062-intel-iotgubuntu-upgrade-linux-image-5-15-0-1062-nvidiaubuntu-upgrade-linux-image-5-15-0-1062-nvidia-lowlatencyubuntu-upgrade-linux-image-5-15-0-1064-gkeubuntu-upgrade-linux-image-5-15-0-1064-kvmubuntu-upgrade-linux-image-5-15-0-1065-oracleubuntu-upgrade-linux-image-5-15-0-1066-gcpubuntu-upgrade-linux-image-5-15-0-1067-awsubuntu-upgrade-linux-image-5-15-0-1070-azureubuntu-upgrade-linux-image-5-15-0-1070-azure-fdeubuntu-upgrade-linux-image-5-15-0-118-genericubuntu-upgrade-linux-image-5-15-0-118-generic-64kubuntu-upgrade-linux-image-5-15-0-118-generic-lpaeubuntu-upgrade-linux-image-5-15-0-118-lowlatencyubuntu-upgrade-linux-image-5-15-0-118-lowlatency-64kubuntu-upgrade-linux-image-6-8-0-1008-gkeubuntu-upgrade-linux-image-6-8-0-1009-raspiubuntu-upgrade-linux-image-6-8-0-1010-ibmubuntu-upgrade-linux-image-6-8-0-1010-oemubuntu-upgrade-linux-image-6-8-0-1010-oracleubuntu-upgrade-linux-image-6-8-0-1010-oracle-64kubuntu-upgrade-linux-image-6-8-0-1011-nvidiaubuntu-upgrade-linux-image-6-8-0-1011-nvidia-64kubuntu-upgrade-linux-image-6-8-0-1011-nvidia-lowlatencyubuntu-upgrade-linux-image-6-8-0-1011-nvidia-lowlatency-64kubuntu-upgrade-linux-image-6-8-0-1012-azureubuntu-upgrade-linux-image-6-8-0-1012-azure-fdeubuntu-upgrade-linux-image-6-8-0-1012-gcpubuntu-upgrade-linux-image-6-8-0-1013-awsubuntu-upgrade-linux-image-6-8-0-40-genericubuntu-upgrade-linux-image-6-8-0-40-generic-64kubuntu-upgrade-linux-image-6-8-0-40-lowlatencyubuntu-upgrade-linux-image-6-8-0-40-lowlatency-64kubuntu-upgrade-linux-image-awsubuntu-upgrade-linux-image-aws-lts-22-04ubuntu-upgrade-linux-image-azureubuntu-upgrade-linux-image-azure-cvmubuntu-upgrade-linux-image-azure-fdeubuntu-upgrade-linux-image-azure-fde-lts-22-04ubuntu-upgrade-linux-image-azure-lts-22-04ubuntu-upgrade-linux-image-gcpubuntu-upgrade-linux-image-gcp-lts-22-04ubuntu-upgrade-linux-image-genericubuntu-upgrade-linux-image-generic-64kubuntu-upgrade-linux-image-generic-64k-hwe-20-04ubuntu-upgrade-linux-image-generic-64k-hwe-24-04ubuntu-upgrade-linux-image-generic-hwe-20-04ubuntu-upgrade-linux-image-generic-hwe-24-04ubuntu-upgrade-linux-image-generic-lpaeubuntu-upgrade-linux-image-generic-lpae-hwe-20-04ubuntu-upgrade-linux-image-gkeubuntu-upgrade-linux-image-gke-5-15ubuntu-upgrade-linux-image-gkeopubuntu-upgrade-linux-image-gkeop-5-15ubuntu-upgrade-linux-image-ibmubuntu-upgrade-linux-image-ibm-classicubuntu-upgrade-linux-image-ibm-lts-24-04ubuntu-upgrade-linux-image-intelubuntu-upgrade-linux-image-intel-iotgubuntu-upgrade-linux-image-kvmubuntu-upgrade-linux-image-lowlatencyubuntu-upgrade-linux-image-lowlatency-64kubuntu-upgrade-linux-image-lowlatency-64k-hwe-20-04ubuntu-upgrade-linux-image-lowlatency-hwe-20-04ubuntu-upgrade-linux-image-nvidiaubuntu-upgrade-linux-image-nvidia-6-8ubuntu-upgrade-linux-image-nvidia-64kubuntu-upgrade-linux-image-nvidia-64k-6-8ubuntu-upgrade-linux-image-nvidia-lowlatencyubuntu-upgrade-linux-image-nvidia-lowlatency-64kubuntu-upgrade-linux-image-oem-20-04ubuntu-upgrade-linux-image-oem-20-04bubuntu-upgrade-linux-image-oem-20-04cubuntu-upgrade-linux-image-oem-20-04dubuntu-upgrade-linux-image-oem-24-04ubuntu-upgrade-linux-image-oem-24-04aubuntu-upgrade-linux-image-oracleubuntu-upgrade-linux-image-oracle-64kubuntu-upgrade-linux-image-oracle-lts-22-04ubuntu-upgrade-linux-image-raspiubuntu-upgrade-linux-image-raspi-nolpaeubuntu-upgrade-linux-image-virtualubuntu-upgrade-linux-image-virtual-hwe-20-04ubuntu-upgrade-linux-image-virtual-hwe-24-04ubuntu-upgrade-linux-image-xilinx-zynqmp
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