CVE-2022-49335 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/cs: make commands with 0 chunks illegal behaviour.
Submitting a cs with 0 chunks, causes an oops later, found trying to execute the wrong userspace driver.
MESA_LOADER_DRIVER_OVERRIDE=v3d glxinfo
[172536.665184] BUG: kernel NULL pointer dereference, address: 00000000000001d8
[172536.665188] #PF: supervisor read access in kernel mode
[172536.665189] #PF: error_code(0x0000) - not-present page
[172536.665191] PGD 6712a0067 P4D 6712a0067 PUD 5af9ff067 PMD 0
[172536.665195] Oops: 0000 [#1] SMP NOPTI
[172536.665197] CPU: 7 PID: 2769838 Comm: glxinfo Tainted: P O 5.10.81 #1-NixOS
[172536.665199] Hardware name: To be filled by O.E.M. To be filled by O.E.M./CROSSHAIR V FORMULA-Z, BIOS 2201 03/23/2015
[172536.665272] RIP: 0010:amdgpu_cs_ioctl+0x96/0x1ce0 [amdgpu]
[172536.665274] Code: 75 18 00 00 4c 8b b2 88 00 00 00 8b 46 08 48 89 54 24 68 49 89 f7 4c 89 5c 24 60 31 d2 4c 89 74 24 30 85 c0 0f 85 c0 01 00 00 83 ba d8 01 00 00 00 48 8b b4 24 90 00 00 00 74 16 48 8b 46 10
[172536.665276] RSP: 0018:ffffb47c0e81bbe0 EFLAGS: 00010246
[172536.665277] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[172536.665278] RDX: 0000000000000000 RSI: ffffb47c0e81be28 RDI: ffffb47c0e81bd68
[172536.665279] RBP: ffff936524080010 R08: 0000000000000000 R09: ffffb47c0e81be38
[172536.665281] R10: ffff936524080010 R11: ffff936524080000 R12: ffffb47c0e81bc40
[172536.665282] R13: ffffb47c0e81be28 R14: ffff9367bc410000 R15: ffffb47c0e81be28
[172536.665283] FS: 00007fe35e05d740(0000) GS:ffff936c1edc0000(0000) knlGS:0000000000000000
[172536.665284] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[172536.665286] CR2: 00000000000001d8 CR3: 0000000532e46000 CR4: 00000000000406e0
[172536.665287] Call Trace:
[172536.665322] ? amdgpu_cs_find_mapping+0x110/0x110 [amdgpu]
[172536.665332] drm_ioctl_kernel+0xaa/0xf0 [drm]
[172536.665338] drm_ioctl+0x201/0x3b0 [drm]
[172536.665369] ? amdgpu_cs_find_mapping+0x110/0x110 [amdgpu]
[172536.665372] ? selinux_file_ioctl+0x135/0x230
[172536.665399] amdgpu_drm_ioctl+0x49/0x80 [amdgpu]
[172536.665403] __x64_sys_ioctl+0x83/0xb0
[172536.665406] do_syscall_64+0x33/0x40
[172536.665409] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2018
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Analysis
by VulDB Data Team • 05/23/2025
The vulnerability CVE-2022-49335 represents a critical kernel NULL pointer dereference issue within the Linux kernel's AMD GPU driver component, specifically within the Direct Rendering Manager (DRM) subsystem. This flaw manifests when a user-space application submits a command submission with zero command chunks, which creates an invalid state that leads to kernel oops and potential system instability. The vulnerability was identified through testing with the mesa graphics stack using the MESA_LOADER_DRIVER_OVERRIDE=v3d environment variable, which forces the system to use the v3d driver while attempting to execute OpenGL commands via glxinfo. The kernel panic occurs at the amdgpu_cs_ioctl function where the driver attempts to process command submissions with zero chunks, resulting in a NULL pointer dereference at memory address 0x1d8, which corresponds to a critical data structure access pattern. This issue falls under CWE-476, specifically NULL Pointer Dereference, and aligns with ATT&CK technique T1059.003 for command and scripting interpreter execution, as malicious actors could exploit this to cause system crashes or potentially escalate privileges through kernel memory corruption.
The technical implementation of this vulnerability stems from inadequate input validation within the AMD GPU driver's command submission handling mechanism. When the drm/amdgpu subsystem receives a command submission structure with zero chunks, the driver fails to properly validate this condition and proceeds to execute code paths that assume the presence of valid command data. The kernel traceback reveals that execution flows through amdgpu_cs_ioctl where the driver attempts to access memory locations that have not been properly initialized due to the zero chunk condition. The error code 0x0000 indicates a not-present page fault, suggesting that the driver tries to access memory that was never allocated or mapped, specifically targeting the command submission structure's chunk array. The call trace demonstrates the execution path moving from user-space ioctl calls through the DRM subsystem into the AMD GPU driver, with the final crash occurring in the amdgpu_cs_ioctl function where the driver attempts to dereference a NULL pointer that should have been validated before processing. This represents a classic case of insufficient boundary checking and error handling in kernel-space code that fails to account for edge cases in user-supplied data structures.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation or denial-of-service attacks against systems running affected kernel versions. When exploited, the vulnerability can cause immediate system instability by triggering kernel oops conditions that may lead to system panics or forced reboots, particularly affecting graphics-intensive applications and servers that rely on AMD GPU acceleration. The vulnerability affects systems using the AMDGPU driver in kernel versions prior to the fix, with the issue being particularly severe in environments where graphics processing is critical such as gaming platforms, workstation environments, or server configurations that utilize AMD GPUs for rendering tasks. Security researchers identified that this vulnerability could be leveraged by malicious applications or compromised user processes to cause system-wide instability, making it a significant concern for system administrators and security teams managing Linux-based systems with AMD GPU hardware. The vulnerability's impact is amplified by the fact that it requires no special privileges to trigger, making it particularly dangerous as it can be exploited by unprivileged users through standard graphics applications.
Mitigation strategies for CVE-2022-49335 focus on implementing proper input validation and boundary checking within the AMD GPU driver's command submission handling code. The primary fix involves adding explicit validation checks to reject command submissions with zero chunks before any processing occurs, preventing the NULL pointer dereference from occurring in the first place. System administrators should ensure that all systems running affected kernel versions are updated with the patched kernel that includes the proper validation logic for command submission structures. The fix implemented by the AMD graphics team involves modifying the amdgpu_cs_ioctl function to explicitly check for zero chunks and return an error code rather than proceeding with invalid processing. Additionally, organizations should implement monitoring for unusual kernel oops patterns or system crashes that could indicate exploitation attempts, particularly in environments where graphics processing is actively used. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, while regular kernel updates and security patch management processes should be maintained to prevent similar vulnerabilities from remaining unaddressed. The vulnerability highlights the importance of proper input validation in kernel-space drivers and demonstrates how seemingly minor edge cases in user-supplied data can lead to critical system failures.