CVE-2023-52590

In the Linux kernel, the ocfs2 dlm_mig_lockres_handler trusted the num_locks and lockname_len fields from a DLM_MIG_LOCKRES message without validation. This led to an out-of-bounds read (BUG_ON panic) and a heap out-of-bounds write when copying the lock name into a fixed 32-byte object. Any node in the domain could trigger this.

A vulnerability was found in the Linux kernel's ocfs2 module due to missing validation of directory-index entry counts when reading metadata. The functions ocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() do not bound the de_num_used and de_count fields against the block capacity, allowing a crafted on-disk image to set them to 0xffff and cause an out-of-bounds read past the 4KB metadata block. The flaw is reachable from any path lookup, stat() or open() on an indexed directory once the image is mounted.

In the Linux kernel, the ocfs2 (o2hb) subsystem has a use-after-free bug in the heartbeat region lifecycle. The region is published to the o2net handler table before its delayed works are initialized, and teardown does not fully drain in-flight o2net callbacks. This causes a race and use of freed memory (KASAN slab-use-after-free in __run_timers).

In the Linux kernel, the ocfs2 filesystem has a memory leak during copy-on-write operations triggered by copy_file_range() within the same filesystem. The issue was found by fuzzing and occurs because deallocations are not always run on copy-on-write completion, leading to unreferenced memory allocations.

The Linux kernel ocfs2 module lacked validation of the rl_used and rl_count fields in the refcount block. A crafted or corrupted ocfs2 image with rl_used set to 0xffff causes an out-of-bounds read past the metadata block and a subsequent out-of-bounds memmove during a reflink (FICLONE) operation. Exploitation requires local access (CAP_SYS_ADMIN mounting a crafted image or raw write to the backing block device).

In the Linux kernel, the ocfs2 function ocfs2_dir_foreach_blk_el() on 32-bit kernels incorrectly computed the directory position mask, clearing the high 32 bits of the position. When readdir() crossed the 4 GiB boundary, the position was reset, causing infinite re-enumeration of already-returned directory entries.