CVE-2022-48756 in Linux
Summary
by MITRE • 06/20/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/dsi: invalid parameter check in msm_dsi_phy_enable
The function performs a check on the "phy" input parameter, however, it is used before the check.
Initialize the "dev" variable after the sanity check to avoid a possible NULL pointer dereference.
Addresses-Coverity-ID: 1493860 ("Null pointer dereference")
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/18/2024
The vulnerability identified as CVE-2022-48756 resides within the Linux kernel's display subsystem, specifically in the drm/msm/dsi driver component that manages display serial interface communications for Qualcomm Snapdragon devices. This issue represents a classic null pointer dereference vulnerability that could potentially lead to system instability or denial of service conditions. The flaw manifests in the msm_dsi_phy_enable function where the driver fails to properly validate input parameters before utilizing them in critical operations.
The technical implementation of this vulnerability stems from improper parameter validation ordering within the msm_dsi_phy_enable function. The driver performs a check on the "phy" input parameter but executes operations using this parameter before the validation occurs. This sequence flaw creates a window where a NULL pointer could be dereferenced if the validation fails or if malicious input is provided. The function's design pattern violates fundamental security principles by not establishing proper input sanitization before parameter usage, creating an exploitable condition that could be leveraged by attackers with access to the display subsystem.
The operational impact of this vulnerability extends beyond simple system instability as it represents a potential denial of service vector that could affect device functionality. When the NULL pointer dereference occurs, it typically results in a kernel oops or system crash, which could disrupt display operations and potentially affect other kernel subsystems that depend on proper display functionality. In embedded systems or mobile devices where display operations are critical for user interaction, such a vulnerability could render devices temporarily unusable until system reboot occurs. The vulnerability affects systems using Qualcomm Snapdragon chipsets that implement the msm display subsystem, particularly those utilizing dsi interfaces for external displays or internal panel connections.
Mitigation strategies for CVE-2022-48756 should focus on implementing proper parameter validation ordering within the affected driver code. The fix involves repositioning the initialization of the "dev" variable to occur after the sanity check on the "phy" parameter, ensuring that all input validation occurs before any parameter usage. This approach aligns with secure coding practices outlined in CWE-476 which addresses null pointer dereference vulnerabilities and follows the principle of input validation before processing. System administrators should ensure that kernel updates containing the patched msm_dsi_phy_enable function are deployed promptly across affected systems, particularly in enterprise environments where display functionality is critical for operations. The vulnerability also highlights the importance of static analysis tools like Coverity in identifying such subtle but critical flaws in kernel code, demonstrating how automated analysis can uncover security issues that might otherwise remain undetected during traditional code review processes. This fix exemplifies the ATT&CK framework's relevance in kernel security where such vulnerabilities could potentially be leveraged for privilege escalation or system compromise if exploited in conjunction with other attack vectors.