CVE-2024-26773

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ext4: avoid allocating blocks from corrupted group in ext4_mb_try_best_found()

Determine if the group block bitmap is corrupted before using ac_b_ex in

ext4_mb_try_best_found() to avoid allocating blocks from a group with a

corrupted block bitmap in the following concurrency and making the

situation worse.

ext4_mb_regular_allocator

ext4_lock_group(sb, group)

ext4_mb_good_group

// check if the group bbitmap is corrupted

ext4_mb_complex_scan_group

// Scan group gets ac_b_ex but doesn't use it

ext4_unlock_group(sb, group)

ext4_mark_group_bitmap_corrupted(group)

// The block bitmap was corrupted during

// the group unlock gap.

ext4_mb_try_best_found

ext4_lock_group(ac->ac_sb, group)

ext4_mb_use_best_found

mb_mark_used

// Allocating blocks in block bitmap corrupted group

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References