title: ext4: avoid allocating blocks from corrupted group in ext4_mb_try_best_found()
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
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 1da177e4c3f4, lessThan: 21f8cfe79f77, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 260fc96283c0, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 927794a02169, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 4c21fa60a6f4, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: f97e75fa4e12, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 0184747b552d, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: a2576ae9a35c, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 4530b3660d39, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 4.19.308, lessThanOrEqual: 4.19.*, status: unaffected, versionType: custom
version: 5.4.270, lessThanOrEqual: 5.4.*, status: unaffected, versionType: custom
version: 5.10.211, lessThanOrEqual: 5.10.*, status: unaffected, versionType: custom
version: 5.15.150, lessThanOrEqual: 5.15.*, status: unaffected, versionType: custom
version: 6.1.80, lessThanOrEqual: 6.1.*, status: unaffected, versionType: custom
version: 6.6.19, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.7, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
