CVE-2022-48932 in Linux
Summary
by MITRE • 08/22/2024
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: DR, Fix slab-out-of-bounds in mlx5_cmd_dr_create_fte
When adding a rule with 32 destinations, we hit the following out-of-band access issue:
BUG: KASAN: slab-out-of-bounds in mlx5_cmd_dr_create_fte+0x18ee/0x1e70
This patch fixes the issue by both increasing the allocated buffers to accommodate for the needed actions and by checking the number of actions to prevent this issue when a rule with too many actions is provided.
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Analysis
by VulDB Data Team • 08/23/2024
The vulnerability identified as CVE-2022-48932 represents a critical slab-out-of-bounds memory access issue within the Mellanox mlx5 network driver component of the Linux kernel. This flaw specifically affects the device router functionality through the mlx5_cmd_dr_create_fte function, which handles the creation of flow table entries for network packet routing. The vulnerability manifests when attempting to add network rules with 32 destinations, triggering a kernel memory corruption scenario that can lead to system instability or potential privilege escalation. The issue resides in the kernel's memory management subsystem where insufficient buffer allocation occurs during the processing of complex flow rules, creating a scenario where memory accesses extend beyond the allocated slab boundaries.
The technical implementation of this vulnerability stems from inadequate input validation and buffer size calculation within the mlx5 driver's device router subsystem. When processing flow table entries with multiple destinations, the driver fails to properly account for the memory requirements needed to store all destination actions, resulting in a classic out-of-bounds memory access pattern. The kernel address sanitizer (KASAN) detection confirms that the issue occurs at offset 0x18ee within the mlx5_cmd_dr_create_fte function, indicating that the driver attempts to access memory beyond the allocated buffer boundaries. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and represents a direct violation of memory safety principles in kernel space operations.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling attackers to exploit the memory corruption for privilege escalation or denial-of-service attacks against systems running affected Linux kernel versions. Systems utilizing Mellanox network adapters with device router functionality are particularly at risk, as the vulnerability can be triggered through legitimate network rule creation operations. The attack surface includes any network infrastructure or virtualization platforms that rely on mlx5 driver capabilities for packet routing, making this vulnerability particularly concerning for enterprise environments and cloud computing infrastructures. The vulnerability also aligns with ATT&CK technique T1059.003 for command and scripting interpreter, as exploitation could involve crafting malicious network rules to trigger the memory corruption.
Mitigation strategies for CVE-2022-48932 require immediate patch application from the Linux kernel maintainers, as the vulnerability has been addressed through buffer size increases and enhanced action count validation. Organizations should prioritize updating their kernel versions to include the patched mlx5 driver implementation that properly allocates sufficient memory buffers for handling maximum destination counts and validates action parameters before processing. Additionally, system administrators should implement monitoring for KASAN reports and kernel memory corruption events to detect potential exploitation attempts. Network administrators should consider temporarily limiting the number of destinations per flow rule in affected systems until full patch deployment is complete, though this represents a temporary workaround rather than a permanent solution. The fix demonstrates proper defensive programming practices by implementing both proactive buffer allocation increases and reactive validation checks to prevent the out-of-bounds memory access condition from occurring.