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ocfs2: validate dx_root extent list fields during block read

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Patch series "ocfs2: consolidate extent list validation into block read
callbacks".

ocfs2 validates extent list fields (l_count, l_next_free_rec) at various
points during extent tree traversal.  This is fragile because each caller
must remember to check for corrupted on-disk data before using it.

This series moves those checks into the block read validation callbacks
(ocfs2_validate_dx_root and ocfs2_validate_extent_block), so corrupted
fields are caught early at block read time.  Redundant post-read checks
are then removed.


This patch (of 4):

Move the extent list l_count validation from ocfs2_dx_dir_lookup_rec()
into ocfs2_validate_dx_root(), so that corrupted on-disk fields are caught
early at block read time rather than during directory lookups.

Additionally, add a l_next_free_rec <= l_count check to prevent
out-of-bounds access when iterating over extent records.

Both checks are skipped for inline dx roots (OCFS2_DX_FLAG_INLINE), which
use dr_entries instead of dr_list.

Link: https://lkml.kernel.org/r/20260403090803.3860971-1-joseph.qi@linux.alibaba.com
Link: https://lkml.kernel.org/r/20260403090803.3860971-2-joseph.qi@linux.alibaba.com
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Heming Zhao <heming.zhao@suse.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Joseph Qi
2026-04-03 17:08:00 +08:00
committed by Andrew Morton
parent 7de554cabf
commit 775c17386a
1 changed files with 25 additions and 9 deletions
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34
fs/ocfs2/dir.c
View File

@@ -593,7 +593,7 @@ static int ocfs2_validate_dx_root(struct super_block *sb,
mlog(ML_ERROR,
"Checksum failed for dir index root block %llu\n",
(unsigned long long)bh->b_blocknr);
return ret;
goto bail;
}
if (!OCFS2_IS_VALID_DX_ROOT(dx_root)) {
@@ -601,8 +601,32 @@ static int ocfs2_validate_dx_root(struct super_block *sb,
"Dir Index Root # %llu has bad signature %.*s\n",
(unsigned long long)le64_to_cpu(dx_root->dr_blkno),
7, dx_root->dr_signature);
goto bail;
}
if (!(dx_root->dr_flags & OCFS2_DX_FLAG_INLINE)) {
struct ocfs2_extent_list *el = &dx_root->dr_list;
if (le16_to_cpu(el->l_count) != ocfs2_extent_recs_per_dx_root(sb)) {
ret = ocfs2_error(sb,
"Dir Index Root # %llu has invalid l_count %u (expected %u)\n",
(unsigned long long)le64_to_cpu(dx_root->dr_blkno),
le16_to_cpu(el->l_count),
ocfs2_extent_recs_per_dx_root(sb));
goto bail;
}
if (le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count)) {
ret = ocfs2_error(sb,
"Dir Index Root # %llu has invalid l_next_free_rec %u (l_count %u)\n",
(unsigned long long)le64_to_cpu(dx_root->dr_blkno),
le16_to_cpu(el->l_next_free_rec),
le16_to_cpu(el->l_count));
goto bail;
}
}
bail:
return ret;
}
@@ -791,14 +815,6 @@ static int ocfs2_dx_dir_lookup_rec(struct inode *inode,
struct ocfs2_extent_block *eb;
struct ocfs2_extent_rec *rec = NULL;
if (le16_to_cpu(el->l_count) !=
ocfs2_extent_recs_per_dx_root(inode->i_sb)) {
ret = ocfs2_error(inode->i_sb,
"Inode %lu has invalid extent list length %u\n",
inode->i_ino, le16_to_cpu(el->l_count));
goto out;
}
if (el->l_tree_depth) {
ret = ocfs2_find_leaf(INODE_CACHE(inode), el, major_hash,
&eb_bh);