CVE-2024-36009: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: ax25: Fix netdev refcount issue The dev_tracker is added to ax25_cb in ax25_bind(). When the ax25 device is detaching, the dev_tracker of ax25_cb should be deallocated in ax25_kill_by_device() instead of the dev_tracker of ax25_dev. The log reported by ref_tracker is shown below: [ 80.884935] ref_tracker: reference already released. [ 80.885150] ref_tracker: allocated in: [ 80.885349] ax25_dev_device_up+0x105/0x540 [ 80.885730] ax25_device_event+0xa4/0x420 [ 80.885730] notifier_call_chain+0xc9/0x1e0 [ 80.885730] __dev_notify_flags+0x138/0x280 [ 80.885730] dev_change_flags+0xd7/0x180 [ 80.885730] dev_ifsioc+0x6a9/0xa30 [ 80.885730] dev_ioctl+0x4d8/0xd90 [ 80.885730] sock_do_ioctl+0x1c2/0x2d0 [ 80.885730] sock_ioctl+0x38b/0x4f0 [ 80.885730] __se_sys_ioctl+0xad/0xf0 [ 80.885730] do_syscall_64+0xc4/0x1b0 [ 80.885730] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 80.885730] ref_tracker: freed in: [ 80.885730] ax25_device_event+0x272/0x420 [ 80.885730] notifier_call_chain+0xc9/0x1e0 [ 80.885730] dev_close_many+0x272/0x370 [ 80.885730] unregister_netdevice_many_notify+0x3b5/0x1180 [ 80.885730] unregister_netdev+0xcf/0x120 [ 80.885730] sixpack_close+0x11f/0x1b0 [ 80.885730] tty_ldisc_kill+0xcb/0x190 [ 80.885730] tty_ldisc_hangup+0x338/0x3d0 [ 80.885730] __tty_hangup+0x504/0x740 [ 80.885730] tty_release+0x46e/0xd80 [ 80.885730] __fput+0x37f/0x770 [ 80.885730] __x64_sys_close+0x7b/0xb0 [ 80.885730] do_syscall_64+0xc4/0x1b0 [ 80.885730] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 80.893739] ------------[ cut here ]------------ [ 80.894030] WARNING: CPU: 2 PID: 140 at lib/ref_tracker.c:255 ref_tracker_free+0x47b/0x6b0 [ 80.894297] Modules linked in: [ 80.894929] CPU: 2 PID: 140 Comm: ax25_conn_rel_6 Not tainted 6.9.0-rc4-g8cd26fd90c1a #11 [ 80.895190] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qem4 [ 80.895514] RIP: 0010:ref_tracker_free+0x47b/0x6b0 [ 80.895808] Code: 83 c5 18 4c 89 eb 48 c1 eb 03 8a 04 13 84 c0 0f 85 df 01 00 00 41 83 7d 00 00 75 4b 4c 89 ff 9 [ 80.896171] RSP: 0018:ffff888009edf8c0 EFLAGS: 00000286 [ 80.896339] RAX: 1ffff1100141ac00 RBX: 1ffff1100149463b RCX: dffffc0000000000 [ 80.896502] RDX: 0000000000000001 RSI: 0000000000000246 RDI: ffff88800a0d6518 [ 80.896925] RBP: ffff888009edf9b0 R08: ffff88806d3288d3 R09: 1ffff1100da6511a [ 80.897212] R10: dffffc0000000000 R11: ffffed100da6511b R12: ffff88800a4a31d4 [ 80.897859] R13: ffff88800a4a31d8 R14: dffffc0000000000 R15: ffff88800a0d6518 [ 80.898279] FS: 00007fd88b7fe700(0000) GS:ffff88806d300000(0000) knlGS:0000000000000000 [ 80.899436] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 80.900181] CR2: 00007fd88c001d48 CR3: 000000000993e000 CR4: 00000000000006f0 ... [ 80.935774] ref_tracker: sp%d@000000000bb9df3d has 1/1 users at [ 80.935774] ax25_bind+0x424/0x4e0 [ 80.935774] __sys_bind+0x1d9/0x270 [ 80.935774] __x64_sys_bind+0x75/0x80 [ 80.935774] do_syscall_64+0xc4/0x1b0 [ 80.935774] entry_SYSCALL_64_after_hwframe+0x67/0x6f Change ax25_dev->dev_tracker to the dev_tracker of ax25_cb in order to mitigate the bug.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	4.14.277 — 4.15
linux	linux_kernel	4.19.240 — 4.20
linux	linux_kernel	5.4.190 — 5.5
linux	linux_kernel	5.10.112 — 5.11
linux	linux_kernel	5.15.35 — 5.16
linux	linux_kernel	5.17.1 — 6.1.90
linux	linux_kernel	6.2 — 6.6.30
linux	linux_kernel	6.7 — 6.8.9
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/0d14f104027e30720582448706c7d6b43065c851 https://git.kernel.org/stable/c/467324bcfe1a31ec65d0cf4aa59421d6b7a7d52b https://git.kernel.org/stable/c/4fee8fa86a15d7790268eea458b1aec69c695530 https://git.kernel.org/stable/c/c42b073d9af4a5329b25b17390c63ab3847f30e8 https://git.kernel.org/stable/c/0d14f104027e30720582448706c7d6b43065c851 https://git.kernel.org/stable/c/467324bcfe1a31ec65d0cf4aa59421d6b7a7d52b https://git.kernel.org/stable/c/4fee8fa86a15d7790268eea458b1aec69c695530 https://git.kernel.org/stable/c/c42b073d9af4a5329b25b17390c63ab3847f30e8

Other References

http://www.openwall.com/lists/oss-security/2024/05/30/1 http://www.openwall.com/lists/oss-security/2024/05/30/2

Frequently Asked Questions

What is CVE-2024-36009? +

In the Linux kernel, the following vulnerability has been resolved: ax25: Fix netdev refcount issue The dev_tracker is added to ax25_cb in ax25_bind(). When the ax25 device is detaching, the dev_tracker of ax25_cb should be deallocated in ax25_kill_by_device() instead of the dev_tracker of ax25_dev. The log reported by ref_tracker is shown below: [ 80.884935] ref_tracker: reference already released. [ 80.885150] ref_tracker: allocated in: [ 80.885349] ax25_dev_device_up+0x105/0x540 [ 80.885730] ax25_device_event+0xa4/0x420 [ 80.885730] notifier_call_chain+0xc9/0x1e0 [ 80.885730] __dev_notify_flags+0x138/0x280 [ 80.885730] dev_change_flags+0xd7/0x180 [ 80.885730] dev_ifsioc+0x6a9/0xa30 [ 80.885730] dev_ioctl+0x4d8/0xd90 [ 80.885730] sock_do_ioctl+0x1c2/0x2d0 [ 80.885730] sock_ioctl+0x38b/0x4f0 [ 80.885730] __se_sys_ioctl+0xad/0xf0 [ 80.885730] do_syscall_64+0xc4/0x1b0 [ 80.885730] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 80.885730] ref_tracker: freed in: [ 80.885730] ax25_device_event+0x272/0x420 [ 80.885730] notifier_call_chain+0xc9/0x1e0 [ 80.885730] dev_close_many+0x272/0x370 [ 80.885730] unregister_netdevice_many_notify+0x3b5/0x1180 [ 80.885730] unregister_netdev+0xcf/0x120 [ 80.885730] sixpack_close+0x11f/0x1b0 [ 80.885730] tty_ldisc_kill+0xcb/0x190 [ 80.885730] tty_ldisc_hangup+0x338/0x3d0 [ 80.885730] __tty_hangup+0x504/0x740 [ 80.885730] tty_release+0x46e/0xd80 [ 80.885730] __fput+0x37f/0x770 [ 80.885730] __x64_sys_close+0x7b/0xb0 [ 80.885730] do_syscall_64+0xc4/0x1b0 [ 80.885730] entry_SYSCALL_64_after_hwframe+0x67/0x6f [ 80.893739] ------------[ cut here ]------------ [ 80.894030] WARNING: CPU: 2 PID: 140 at lib/ref_tracker.c:255 ref_tracker_free+0x47b/0x6b0 [ 80.894297] Modules linked in: [ 80.894929] CPU: 2 PID: 140 Comm: ax25_conn_rel_6 Not tainted 6.9.0-rc4-g8cd26fd90c1a #11 [ 80.895190] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qem4 [ 80.895514] RIP: 0010:ref_tracker_free+0x47b/0x6b0 [ 80.895808] Code: 83 c5 18 4c 89 eb 48 c1 eb 03 8a 04 13 84 c0 0f 85 df 01 00 00 41 83 7d 00 00 75 4b 4c 89 ff 9 [ 80.896171] RSP: 0018:ffff888009edf8c0 EFLAGS: 00000286 [ 80.896339] RAX: 1ffff1100141ac00 RBX: 1ffff1100149463b RCX: dffffc0000000000 [ 80.896502] RDX: 0000000000000001 RSI: 0000000000000246 RDI: ffff88800a0d6518 [ 80.896925] RBP: ffff888009edf9b0 R08: ffff88806d3288d3 R09: 1ffff1100da6511a [ 80.897212] R10: dffffc0000000000 R11: ffffed100da6511b R12: ffff88800a4a31d4 [ 80.897859] R13: ffff88800a4a31d8 R14: dffffc0000000000 R15: ffff88800a0d6518 [ 80.898279] FS: 00007fd88b7fe700(0000) GS:ffff88806d300000(0000) knlGS:0000000000000000 [ 80.899436] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 80.900181] CR2: 00007fd88c001d48 CR3: 000000000993e000 CR4: 00000000000006f0 ... [ 80.935774] ref_tracker: sp%d@000000000bb9df3d has 1/1 users at [ 80.935774] ax25_bind+0x424/0x4e0 [ 80.935774] __sys_bind+0x1d9/0x270 [ 80.935774] __x64_sys_bind+0x75/0x80 [ 80.935774] do_syscall_64+0xc4/0x1b0 [ 80.935774] entry_SYSCALL_64_after_hwframe+0x67/0x6f Change ax25_dev->dev_tracker to the dev_tracker of ax25_cb in order to mitigate the bug. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2024-36009? +

CVE-2024-36009 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-36009? +

CVE-2024-36009 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-36009? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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