CVE-2022-48832 in Linux
Summary
by MITRE • 07/16/2024
In the Linux kernel, the following vulnerability has been resolved:
audit: don't deref the syscall args when checking the openat2 open_how::flags
As reported by Jeff, dereferencing the openat2 syscall argument in audit_match_perm() to obtain the open_how::flags can result in an oops/page-fault. This patch fixes this by using the open_how struct that we store in the audit_context with audit_openat2_how().
Independent of this patch, Richard Guy Briggs posted a similar patch to the audit mailing list roughly 40 minutes after this patch was posted.
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Analysis
by VulDB Data Team • 10/07/2025
The vulnerability identified as CVE-2022-48832 represents a critical flaw in the Linux kernel's audit subsystem that could lead to system instability through kernel page faults. This issue specifically affects the audit_match_perm() function which is responsible for checking permissions during system call auditing operations. The flaw occurs when the kernel attempts to dereference syscall arguments during the audit process for openat2 system calls, creating a scenario where invalid memory access can trigger a kernel oops condition. This type of vulnerability falls under the category of improper access to memory locations, which is classified as CWE-125 in the Common Weakness Enumeration catalog.
The technical implementation of this vulnerability stems from how the Linux kernel audit subsystem handles the openat2 system call, which is used to open files with more granular control than traditional open calls. When audit_match_perm() attempts to access the open_how::flags field from syscall arguments, it directly dereferences memory that may not be properly initialized or accessible, leading to page fault exceptions. This occurs because the audit subsystem tries to access syscall parameters that are not yet fully validated or stored in the audit_context structure. The flaw is particularly dangerous because it operates at the kernel level where such errors can result in system crashes or potential privilege escalation scenarios. The vulnerability demonstrates a classic case of insufficient input validation and improper memory management in kernel space operations.
The operational impact of CVE-2022-48832 extends beyond simple system crashes, potentially affecting system availability and stability in environments where extensive auditing is enabled. Systems that rely heavily on audit logging for security monitoring or compliance purposes are particularly at risk since the vulnerability can be triggered by legitimate openat2 system call operations. Attackers could potentially exploit this vulnerability to cause denial of service conditions by repeatedly invoking openat2 operations that trigger the kernel page fault. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1490 which involves creating or manipulating system resources to cause system instability. The patch implementation addresses this by utilizing the open_how structure that is already stored in the audit_context, thereby avoiding direct dereferencing of potentially problematic syscall arguments and ensuring proper memory access patterns.
The resolution for this vulnerability involves modifying the audit_match_perm() function to reference pre-stored audit_context data rather than attempting to directly access syscall arguments during permission checking. This approach follows established kernel security best practices by ensuring that all memory accesses are properly validated and that system call parameters are handled through established audit infrastructure rather than direct memory dereferencing. The fix demonstrates proper defensive programming principles and aligns with the kernel's security architecture that emphasizes safe memory access patterns in audit subsystem operations. The vulnerability's resolution also highlights the importance of maintaining proper synchronization between syscall parameter handling and audit subsystem operations, ensuring that audit data structures are properly initialized before being accessed. This type of fix is particularly important in kernel security contexts where improper memory access can lead to privilege escalation or system compromise, and the solution reflects the kernel community's commitment to maintaining robust security controls in core system components.