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CVE-2024-44952
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CVE-2024-44952
MITRE ATT&CK
Collection
Command and Control
Credential Access
Defense Evasion
Discovery
Execution
Exfiltration
Impact
Initial Access
Lateral Movement
Persistence
Privilege Escalation
Topic Tags
Description
In the Linux kernel, the following vulnerability has been resolved:
driver core: Fix uevent_show() vs driver detach race
uevent_show() wants to de-reference dev->driver->name. There is no clean
way for a device attribute to de-reference dev->driver unless that
attribute is defined via (struct device_driver).dev_groups. Instead, the
anti-pattern of taking the device_lock() in the attribute handler risks
deadlocks with code paths that remove device attributes while holding
the lock.
This deadlock is typically invisible to lockdep given the device_lock()
is marked lockdep_set_novalidate_class(), but some subsystems allocate a
local lockdep key for @dev->mutex to reveal reports of the form:
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc7+ #275 Tainted: G OE N
modprobe/2374 is trying to acquire lock:
ffff8c2270070de0 (kn->active#6){++++}–{0:0}, at: __kernfs_remove+0xde/0x220
but task is already holding lock:
ffff8c22016e88f8 (&cxl_root_key){+.+.}–{3:3}, at: device_release_driver_internal+0x39/0x210
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
–> #1 (&cxl_root_key){+.+.}–{3:3}:
__mutex_lock+0x99/0xc30 uevent_show+0xac/0x130 dev_attr_show+0x18/0x40 sysfs_kf_seq_show+0xac/0xf0 seq_read_iter+0x110/0x450 vfs_read+0x25b/0x340 ksys_read+0x67/0xf0 do_syscall_64+0x75/0x190 entry_SYSCALL_64_after_hwframe+0x76/0x7e
–> #0 (kn->active#6){++++}–{0:0}:
__lock_acquire+0x121a/0x1fa0 lock_acquire+0xd6/0x2e0 kernfs_drain+0x1e9/0x200 __kernfs_remove+0xde/0x220 kernfs_remove_by_name_ns+0x5e/0xa0 device_del+0x168/0x410 device_unregister+0x13/0x60 devres_release_all+0xb8/0x110 device_unbind_cleanup+0xe/0x70 device_release_driver_internal+0x1c7/0x210 driver_detach+0x47/0x90 bus_remove_driver+0x6c/0xf0 cxl_acpi_exit+0xc/0x11 [cxl_acpi] __do_sys_delete_module.isra.0+0x181/0x260 do_syscall_64+0x75/0x190 entry_SYSCALL_64_after_hwframe+0x76/0x7e
The observation though is that driver objects are typically much longer
lived than device objects. It is reasonable to perform lockless
de-reference of a @driver pointer even if it is racing detach from a
device. Given the infrequency of driver unregistration, use
synchronize_rcu() in module_remove_driver() to close any potential
races. It is potentially overkill to suffer synchronize_rcu() just to
handle the rare module removal racing uevent_show() event.
Thanks to Tetsuo Handa for the debug analysis of the syzbot report [1].
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General Information
Vendors
- linux
Products
- linux kernel,
- linux kernel 6.11
References
Miscellaneous
Additional Info
Technical Analysis
Report as Emergent Threat Response
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CVE ID
AttackerKB requires a CVE ID in order to pull vulnerability data and references from the CVE list and the National Vulnerability Database. If available, please supply below: