Vulnerabilities > CVE-2022-49496 - Improper Locking vulnerability in Linux Kernel
Summary
In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: prevent kernel crash when rmmod mtk-vcodec-dec.ko If the driver support subdev mode, the parameter "dev->pm.dev" will be NULL in mtk_vcodec_dec_remove. Kernel will crash when try to rmmod mtk-vcodec-dec.ko. [ 4380.702726] pc : do_raw_spin_trylock+0x4/0x80 [ 4380.707075] lr : _raw_spin_lock_irq+0x90/0x14c [ 4380.711509] sp : ffff80000819bc10 [ 4380.714811] x29: ffff80000819bc10 x28: ffff3600c03e4000 x27: 0000000000000000 [ 4380.721934] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 [ 4380.729057] x23: ffff3600c0f34930 x22: ffffd5e923549000 x21: 0000000000000220 [ 4380.736179] x20: 0000000000000208 x19: ffffd5e9213e8ebc x18: 0000000000000020 [ 4380.743298] x17: 0000002000000000 x16: ffffd5e9213e8e90 x15: 696c346f65646976 [ 4380.750420] x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000040 [ 4380.757542] x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 [ 4380.764664] x8 : 0000000000000000 x7 : ffff3600c7273ae8 x6 : ffffd5e9213e8ebc [ 4380.771786] x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000 [ 4380.778908] x2 : 0000000000000000 x1 : ffff3600c03e4000 x0 : 0000000000000208 [ 4380.786031] Call trace: [ 4380.788465] do_raw_spin_trylock+0x4/0x80 [ 4380.792462] __pm_runtime_disable+0x2c/0x1b0 [ 4380.796723] mtk_vcodec_dec_remove+0x5c/0xa0 [mtk_vcodec_dec] [ 4380.802466] platform_remove+0x2c/0x60 [ 4380.806204] __device_release_driver+0x194/0x250 [ 4380.810810] driver_detach+0xc8/0x15c [ 4380.814462] bus_remove_driver+0x5c/0xb0 [ 4380.818375] driver_unregister+0x34/0x64 [ 4380.822288] platform_driver_unregister+0x18/0x24 [ 4380.826979] mtk_vcodec_dec_driver_exit+0x1c/0x888 [mtk_vcodec_dec] [ 4380.833240] __arm64_sys_delete_module+0x190/0x224 [ 4380.838020] invoke_syscall+0x48/0x114 [ 4380.841760] el0_svc_common.constprop.0+0x60/0x11c [ 4380.846540] do_el0_svc+0x28/0x90 [ 4380.849844] el0_svc+0x4c/0x100 [ 4380.852975] el0t_64_sync_handler+0xec/0xf0 [ 4380.857148] el0t_64_sync+0x190/0x194 [ 4380.860801] Code: 94431515 17ffffca d503201f d503245f (b9400004)
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Leveraging Race Conditions This attack targets a race condition occurring when multiple processes access and manipulate the same resource concurrently and the outcome of the execution depends on the particular order in which the access takes place. The attacker can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance a race condition can occur while accessing a file, the attacker can trick the system by replacing the original file with his version and cause the system to read the malicious file.
- Leveraging Race Conditions via Symbolic Links This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to her. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file she will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.