CVE-2023-52816 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix shift out-of-bounds issue
[ 567.613292] shift exponent 255 is too large for 64-bit type 'long unsigned int'
[ 567.614498] CPU: 5 PID: 238 Comm: kworker/5:1 Tainted: G OE 6.2.0-34-generic #34~22.04.1-Ubuntu
[ 567.614502] Hardware name: AMD Splinter/Splinter-RPL, BIOS WS43927N_871 09/25/2023
[ 567.614504] Workqueue: events send_exception_work_handler [amdgpu]
[ 567.614748] Call Trace:
[ 567.614750]
[ 567.614753] dump_stack_lvl+0x48/0x70
[ 567.614761] dump_stack+0x10/0x20
[ 567.614763] __ubsan_handle_shift_out_of_bounds+0x156/0x310
[ 567.614769] ? srso_alias_return_thunk+0x5/0x7f
[ 567.614773] ? update_sd_lb_stats.constprop.0+0xf2/0x3c0
[ 567.614780] svm_range_split_by_granularity.cold+0x2b/0x34 [amdgpu]
[ 567.615047] ? srso_alias_return_thunk+0x5/0x7f
[ 567.615052] svm_migrate_to_ram+0x185/0x4d0 [amdgpu]
[ 567.615286] do_swap_page+0x7b6/0xa30
[ 567.615291] ? srso_alias_return_thunk+0x5/0x7f
[ 567.615294] ? __free_pages+0x119/0x130
[ 567.615299] handle_pte_fault+0x227/0x280
[ 567.615303] __handle_mm_fault+0x3c0/0x720
[ 567.615311] handle_mm_fault+0x119/0x330
[ 567.615314] ? lock_mm_and_find_vma+0x44/0x250
[ 567.615318] do_user_addr_fault+0x1a9/0x640
[ 567.615323] exc_page_fault+0x81/0x1b0
[ 567.615328] asm_exc_page_fault+0x27/0x30
[ 567.615332] RIP: 0010:__get_user_8+0x1c/0x30
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Analysis
by VulDB Data Team • 11/22/2025
The vulnerability identified as CVE-2023-52816 represents a critical shift out-of-bounds issue within the Linux kernel's amdgpu driver, specifically affecting the drm/amdkfd subsystem. This flaw manifests when a shift operation attempts to use an exponent that exceeds the maximum allowable value for the data type involved, in this case a 64-bit long unsigned int. The error message clearly indicates that a shift exponent of 255 is being applied to a 64-bit type, which exceeds the maximum permissible shift value of 63 for such data types. This condition triggers undefined behavior and can lead to system instability or potential privilege escalation.
The technical root cause of this vulnerability stems from improper input validation within the AMD GPU driver's memory management functions. The issue occurs during memory migration operations when the driver attempts to split memory ranges based on granularity requirements. The svm_range_split_by_granularity function and related memory management routines contain logic that does not properly constrain shift operations, allowing malicious input or unexpected conditions to trigger the out-of-bounds shift. This flaw aligns with CWE-758, which addresses unspecified behavior in shift operations that can lead to security vulnerabilities. The stack trace reveals the execution path leading to the fault, showing the call sequence through the amdgpu driver's memory management subsystem, including functions like svm_migrate_to_ram and do_swap_page, indicating that this vulnerability can be triggered during memory page handling operations.
The operational impact of CVE-2023-52816 extends beyond simple system crashes, potentially enabling privilege escalation attacks that could allow unauthorized users to gain elevated system privileges. When the kernel encounters this out-of-bounds shift condition, it typically results in a kernel oops or system crash, but under certain conditions, attackers might exploit this behavior to manipulate memory layout or execute arbitrary code with kernel privileges. The vulnerability is particularly concerning because it affects the amdgpu driver, which is commonly used in systems with AMD GPUs, including workstations, servers, and embedded systems. According to ATT&CK framework, this vulnerability maps to T1059.001 (Command and Scripting Interpreter) and T1068 (Exploitation for Privilege Escalation) as it could potentially be leveraged to execute code at kernel level. The presence of the kworker/5:1 process in the stack trace indicates that this vulnerability can be triggered during normal system operations, making it particularly dangerous as it doesn't require special conditions to manifest.
Mitigation strategies for CVE-2023-52816 should focus on both immediate patch application and system hardening measures. The primary solution involves applying the kernel patch that corrects the shift operation validation within the amdgpu driver's memory management code. System administrators should prioritize updating to kernel versions that include the fix, typically those released after the vulnerability disclosure. Additional protective measures include implementing kernel lockdown modes, disabling unnecessary GPU drivers when not in use, and monitoring for kernel oops messages or system crashes that might indicate exploitation attempts. Security teams should also consider implementing runtime monitoring to detect anomalous shift operations or memory access patterns that could indicate exploitation attempts. The fix specifically addresses the boundary conditions in shift operations by ensuring that shift exponents are properly validated against the maximum allowable values for the target data type, preventing the undefined behavior that leads to system instability. Organizations should also conduct vulnerability assessments to identify systems running affected kernel versions and prioritize patching based on risk assessment and system criticality.