The Linux kernel's ocfs2 filesystem had a vulnerability in the ocfs2_dir_foreach_blk_el() function where the directory cookie position (ctx->pos) was truncated on 32-bit kernels due to a 32-bit mask applied to a 64-bit signed position value. This truncation caused the high 32 bits of the position to be cleared, resetting the directory read position back into the first 4 GiB block when crossing the 4 GiB boundary. This results in indefinite re-enumeration of directory entries beyond 4 GiB on 32-bit kernels. The fix involves casting the mask operand to loff_t (64-bit) before the bitwise AND operation, ensuring correct 64-bit masking. 64-bit kernels are unaffected by this issue.

On 32-bit Linux kernels using ocfs2, reading directories larger than 4 GiB can cause readdir() to loop indefinitely over the first 4 GiB of directory entries. This can disrupt applications relying on directory enumeration, potentially causing performance degradation or denial of service in directory listing operations. 64-bit kernels are not impacted.

A fix has been implemented in the Linux kernel source code by casting the mask operand to 64-bit before the bitwise operation, preventing position truncation on 32-bit kernels. Users should apply the official kernel update containing this fix. No additional mitigation is required for 64-bit kernels. Patch status is not explicitly stated; check the vendor advisory or kernel release notes for the fixed version and apply updates accordingly.