From: Baokun Li <libaokun1@huawei.com> stable inclusion from stable-v5.10.211 commit 927794a02169778c9c2e7b25c768ab3ea8c1dc03 bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9E2M9 CVE: CVE-2024-26773 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 4530b3660d396a646aad91a787b6ab37cf604b53 ] 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 Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20240104142040.2835097-7-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com> --- fs/ext4/mballoc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 929fc424d68a..1be932fcd7cb 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1853,6 +1853,9 @@ int ext4_mb_try_best_found(struct ext4_allocation_context *ac, return err; ext4_lock_group(ac->ac_sb, group); + if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) + goto out; + max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex); if (max > 0) { @@ -1860,6 +1863,7 @@ int ext4_mb_try_best_found(struct ext4_allocation_context *ac, ext4_mb_use_best_found(ac, e4b); } +out: ext4_unlock_group(ac->ac_sb, group); ext4_mb_unload_buddy(e4b); -- 2.39.2