CVE-2022-48841 in Linux
Summary
by MITRE • 07/16/2024
In the Linux kernel, the following vulnerability has been resolved:
ice: fix NULL pointer dereference in ice_update_vsi_tx_ring_stats()
It is possible to do NULL pointer dereference in routine that updates Tx ring stats. Currently only stats and bytes are updated when ring pointer is valid, but later on ring is accessed to propagate gathered Tx stats onto VSI stats.
Change the existing logic to move to next ring when ring is NULL.
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Analysis
by VulDB Data Team • 07/17/2024
The vulnerability identified as CVE-2022-48841 represents a critical NULL pointer dereference flaw within the Intel Ethernet Network Driver for the Linux kernel, specifically affecting the ice driver module. This issue manifests in the ice_update_vsi_tx_ring_stats() function where the driver attempts to update transmission ring statistics. The flaw occurs when the driver processes network transmission rings without proper validation of ring pointers, creating a potential crash condition that could be exploited to disrupt system operations. The vulnerability impacts systems utilizing Intel Ethernet network adapters that employ the ice driver for network communication.
The technical root cause of this vulnerability stems from inadequate pointer validation within the network driver's statistics update mechanism. During normal operation, the ice driver maintains multiple transmission rings for handling network traffic, with each ring containing statistics that need to be aggregated at the Virtual Switch Interface (VSI) level. The existing code logic only updates statistics and byte counts when a ring pointer is valid, but fails to properly handle cases where ring pointers become NULL during active network processing. When the driver later attempts to access these NULL ring pointers to propagate transmission statistics to the VSI-level statistics structure, a NULL pointer dereference occurs, leading to kernel panic and system instability.
This vulnerability presents significant operational impact for Linux-based systems relying on Intel Ethernet adapters, particularly in server and enterprise environments where network reliability is paramount. The NULL pointer dereference can result in complete system crashes, requiring manual intervention and system reboot to restore normal operation. Attackers could potentially exploit this vulnerability to cause denial of service conditions, disrupting network services and potentially affecting critical infrastructure operations. The vulnerability is especially concerning in high-availability environments where system uptime is critical, as even brief service interruptions could have substantial business impacts.
The fix for CVE-2022-48841 implements a straightforward but critical logic change that addresses the pointer validation issue. The solution modifies the existing code to properly handle NULL ring pointers by moving to the next available ring when a NULL pointer is encountered, rather than attempting to dereference the invalid pointer. This approach aligns with standard defensive programming practices and follows the principle of fail-safe operation in kernel drivers. The fix specifically targets the ice_update_vsi_tx_ring_stats() function and ensures that all ring processing operations maintain proper validation before pointer access. This remediation approach prevents the kernel from crashing while preserving the integrity of network statistics collection and system stability.
From a cybersecurity perspective, this vulnerability demonstrates the importance of robust input validation and defensive programming in kernel space code. The issue relates to CWE-476 which addresses NULL pointer dereference conditions, and represents a typical example of how seemingly minor pointer validation gaps can lead to critical system instability. The vulnerability also maps to ATT&CK technique T1499.004 which involves network denial of service attacks, as the NULL pointer dereference creates conditions that can lead to system unavailability. Organizations should prioritize applying this patch immediately, as the vulnerability exists in the kernel space where exploitation can lead to complete system compromise. The fix exemplifies the need for thorough testing of driver code, particularly in high-traffic network environments where such conditions are more likely to occur.