In the Linux kernel, the following vulnerability has been resolved:
pps: Fix a use-after-free
On a board running ntpd and gpsd, I'm seeing a consistent use-after-free
in sys_exit() from gpsd when rebooting:
pps pps1: removed
------------[ cut here ]------------
kobject: '(null)' (00000000db4bec24): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 2 PID: 440 at lib/kobject.c:734 kobject_put+0x120/0x150
CPU: 2 UID: 299 PID: 440 Comm: gpsd Not tainted 6.11.0-rc6-00308-gb31c44928842 #1
Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kobject_put+0x120/0x150
lr : kobject_put+0x120/0x150
sp : ffffffc0803d3ae0
x29: ffffffc0803d3ae0 x28: ffffff8042dc9738 x27: 0000000000000001
x26: 0000000000000000 x25: ffffff8042dc9040 x24: ffffff8042dc9440
x23: ffffff80402a4620 x22: ffffff8042ef4bd0 x21: ffffff80405cb600
x20: 000000000008001b x19: ffffff8040b3b6e0 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 696e6920746f6e20
x14: 7369203a29343263 x13: 205d303434542020 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
kobject_put+0x120/0x150
cdev_put+0x20/0x3c
__fput+0x2c4/0x2d8
____fput+0x1c/0x38
task_work_run+0x70/0xfc
do_exit+0x2a0/0x924
do_group_exit+0x34/0x90
get_signal+0x7fc/0x8c0
do_signal+0x128/0x13b4
do_notify_resume+0xdc/0x160
el0_svc+0xd4/0xf8
el0t_64_sync_handler+0x140/0x14c
el0t_64_sync+0x190/0x194
---[ end trace 0000000000000000 ]---
...followed by more symptoms of corruption, with similar stacks:
refcount_t: underflow; use-after-free.
kernel BUG at lib/list_debug.c:62!
Kernel panic - not syncing: Oops - BUG: Fatal exception
This happens because pps_device_destruct() frees the pps_device with the
embedded cdev immediately after calling cdev_del(), but, as the comment
above cdev_del() notes, fops for previously opened cdevs are still
callable even after cdev_del() returns. I think this bug has always
been there: I can't explain why it suddenly started happening every time
I reboot this particular board.
In commit d953e0e837e6 ("pps: Fix a use-after free bug when
unregistering a source."), George Spelvin suggested removing the
embedded cdev. That seems like the simplest way to fix this, so I've
implemented his suggestion, using __register_chrdev() with pps_idr
becoming the source of truth for which minor corresponds to which
device.
But now that pps_idr defines userspace visibility instead of cdev_add(),
we need to be sure the pps->dev refcount can't reach zero while
userspace can still find it again. So, the idr_remove() call moves to
pps_unregister_cdev(), and pps_idr now holds a reference to pps->dev.
pps_core: source serial1 got cdev (251:1)
<...>
pps pps1: removed
pps_core: unregistering pps1
pps_core: deallocating pps1
References
Configurations
Configuration 1 (hide)
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History
24 Mar 2025, 19:32
Type | Values Removed | Values Added |
---|---|---|
CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
First Time |
Linux linux Kernel
Linux |
|
References | () https://git.kernel.org/stable/c/1a7735ab2cb9747518a7416fb5929e85442dec62 - Patch | |
References | () https://git.kernel.org/stable/c/785c78ed0d39d1717cca3ef931d3e51337b5e90e - Patch | |
References | () https://git.kernel.org/stable/c/7e5ee3281dc09014367f5112b6d566ba36ea2d49 - Patch | |
References | () https://git.kernel.org/stable/c/85241f7de216f8298f6e48540ea13d7dcd100870 - Patch | |
References | () https://git.kernel.org/stable/c/91932db1d96b2952299ce30c1c693d834d10ace6 - Patch | |
References | () https://git.kernel.org/stable/c/c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7 - Patch | |
References | () https://git.kernel.org/stable/c/c79a39dc8d060b9e64e8b0fa9d245d44befeefbe - Patch | |
References | () https://git.kernel.org/stable/c/cd3bbcb6b3a7caa5ce67de76723b6d8531fb7f64 - Patch |
13 Mar 2025, 13:15
Type | Values Removed | Values Added |
---|---|---|
Summary |
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|
References |
|
27 Feb 2025, 19:15
Type | Values Removed | Values Added |
---|---|---|
CWE | CWE-416 | |
CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
27 Feb 2025, 02:15
Type | Values Removed | Values Added |
---|---|---|
New CVE |
Information
Published : 2025-02-27 02:15
Updated : 2025-03-24 19:32
NVD link : CVE-2024-57979
Mitre link : CVE-2024-57979
CVE.ORG link : CVE-2024-57979
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free