CVE-2024-42271: net/iucv: fix use after free in iucv_sock_close()
First published: Sat Aug 17 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix use after free in iucv_sock_close() iucv_sever_path() is called from process context and from bh context. iucv->path is used as indicator whether somebody else is taking care of severing the path (or it is already removed / never existed). This needs to be done with atomic compare and swap, otherwise there is a small window where iucv_sock_close() will try to work with a path that has already been severed and freed by iucv_callback_connrej() called by iucv_tasklet_fn(). Example: [452744.123844] Call Trace: [452744.123845] ([<0000001e87f03880>] 0x1e87f03880) [452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x138 [452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv] [452744.124336] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv] [452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv] [452744.124345] [<00000000d574794e>] __sock_release+0x5e/0xe8 [452744.124815] [<00000000d5747a0c>] sock_close+0x34/0x48 [452744.124820] [<00000000d5421642>] __fput+0xba/0x268 [452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0 [452744.124832] [<00000000d5145710>] do_notify_resume+0x88/0x90 [452744.124841] [<00000000d5978096>] system_call+0xe2/0x2c8 [452744.125319] Last Breaking-Event-Address: [452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138 [452744.125324] [452744.125325] Kernel panic - not syncing: Fatal exception in interrupt Note that bh_lock_sock() is not serializing the tasklet context against process context, because the check for sock_owned_by_user() and corresponding handling is missing. Ideas for a future clean-up patch: A) Correct usage of bh_lock_sock() in tasklet context, as described in Re-enqueue, if needed. This may require adding return values to the tasklet functions and thus changes to all users of iucv. B) Change iucv tasklet into worker and use only lock_sock() in af_iucv.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | >=3.4<4.19.320 | |
| Linux Kernel | >=4.20<5.4.282 | |
| Linux Kernel | >=5.5<5.10.224 | |
| Linux Kernel | >=5.11<5.15.165 | |
| Linux Kernel | >=5.16<6.1.104 | |
| Linux Kernel | >=6.2<6.6.45 | |
| Linux Kernel | >=6.7<6.10.4 | |
| Linux Kernel | =6.11-rc1 | |
| debian/linux | <=5.10.223-1<=5.10.234-1 | 6.1.129-1 6.1.128-1 6.12.20-1 |
| debian/linux-6.1 | 6.1.129-1~deb11u1 |
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Reference Links
- https://git.kernel.org/stable/c/01437282fd3904810603f3dc98d2cac6b8b6fc84
- https://git.kernel.org/stable/c/37652fbef9809411cea55ea5fa1a170e299efcd0
- https://git.kernel.org/stable/c/69620522c48ce8215e5eb55ffbab8cafee8f407d
- https://git.kernel.org/stable/c/84f40b46787ecb67c7ad08a5bb1376141fa10c01
- https://git.kernel.org/stable/c/8b424c9e44111c5a76f41c6b741f8d4c4179d876
- https://git.kernel.org/stable/c/ac758e1f663fe9bc64f6b47212a2aa18697524f5
- https://git.kernel.org/stable/c/c65f72eec60a34ace031426e04e9aff8e5f04895
- https://git.kernel.org/stable/c/f558120cd709682b739207b48cf7479fd9568431
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-42271
- https://nvd.nist.gov/vuln/detail/CVE-2024-42271
- https://launchpad.net/bugs/cve/CVE-2024-42271
- https://security-tracker.debian.org/tracker/CVE-2024-42271
- https://ubuntu.com/security/CVE-2024-42271
- https://git.kernel.org/linus/f558120cd709682b739207b48cf7479fd9568431
Frequently Asked Questions
What is the severity of CVE-2024-42271?
CVE-2024-42271 is classified as a high severity vulnerability due to its potential impact on the Linux kernel's functionality.
How do I fix CVE-2024-42271?
To fix CVE-2024-42271, update your Linux kernel to a version that is not affected, such as 6.1.123-1 or later.
Which Linux kernel versions are affected by CVE-2024-42271?
CVE-2024-42271 impacts Linux kernel versions between 3.4 and 6.1.104, including several specific versions within that range.
What does CVE-2024-42271 exploit in the Linux kernel?
CVE-2024-42271 exploits a use-after-free vulnerability in the iucv_sock_close function of the Linux kernel.
When was CVE-2024-42271 disclosed?
CVE-2024-42271 was disclosed in June 2024, following its resolution in the Linux kernel.
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