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* [PATCH for 5.4 1/3] ext4: check for out-of-order index extents in ext4_valid_extent_entries()
@ 2022-02-17 22:59 Leah Rumancik
  2022-02-17 22:59 ` [PATCH for 5.4 2/3] ext4: check for inconsistent extents between index and leaf block Leah Rumancik
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Leah Rumancik @ 2022-02-17 22:59 UTC (permalink / raw)
  To: stable; +Cc: Zhang Yi, Theodore Ts'o, Leah Rumancik

From: Zhang Yi <yi.zhang@huawei.com>

commit 8dd27fecede55e8a4e67eef2878040ecad0f0d33 upstream.

After commit 5946d089379a ("ext4: check for overlapping extents in
ext4_valid_extent_entries()"), we can check out the overlapping extent
entry in leaf extent blocks. But the out-of-order extent entry in index
extent blocks could also trigger bad things if the filesystem is
inconsistent. So this patch add a check to figure out the out-of-order
index extents and return error.

[Added pblk argument to ext4_valid_extent_entries because pblk is
updated in the case of overlapping extents. This argument was added
in commit 54d3adbc29f0c7c53890da1683e629cd220d7201.]

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210908120850.4012324-2-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
---
 fs/ext4/extents.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ae73e6793683..4f8736b7e497 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -390,9 +390,12 @@ static int ext4_valid_extent_idx(struct inode *inode,
 
 static int ext4_valid_extent_entries(struct inode *inode,
 				struct ext4_extent_header *eh,
-				int depth)
+				ext4_fsblk_t *pblk, int depth)
 {
 	unsigned short entries;
+	ext4_lblk_t lblock = 0;
+	ext4_lblk_t prev = 0;
+
 	if (eh->eh_entries == 0)
 		return 1;
 
@@ -403,32 +406,36 @@ static int ext4_valid_extent_entries(struct inode *inode,
 		struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 		struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 		ext4_fsblk_t pblock = 0;
-		ext4_lblk_t lblock = 0;
-		ext4_lblk_t prev = 0;
-		int len = 0;
 		while (entries) {
 			if (!ext4_valid_extent(inode, ext))
 				return 0;
 
 			/* Check for overlapping extents */
 			lblock = le32_to_cpu(ext->ee_block);
-			len = ext4_ext_get_actual_len(ext);
 			if ((lblock <= prev) && prev) {
 				pblock = ext4_ext_pblock(ext);
 				es->s_last_error_block = cpu_to_le64(pblock);
 				return 0;
 			}
+			prev = lblock + ext4_ext_get_actual_len(ext) - 1;
 			ext++;
 			entries--;
-			prev = lblock + len - 1;
 		}
 	} else {
 		struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 		while (entries) {
 			if (!ext4_valid_extent_idx(inode, ext_idx))
 				return 0;
+
+			/* Check for overlapping index extents */
+			lblock = le32_to_cpu(ext_idx->ei_block);
+			if ((lblock <= prev) && prev) {
+				*pblk = ext4_idx_pblock(ext_idx);
+				return 0;
+			}
 			ext_idx++;
 			entries--;
+			prev = lblock;
 		}
 	}
 	return 1;
@@ -462,7 +469,7 @@ static int __ext4_ext_check(const char *function, unsigned int line,
 		error_msg = "invalid eh_entries";
 		goto corrupted;
 	}
-	if (!ext4_valid_extent_entries(inode, eh, depth)) {
+	if (!ext4_valid_extent_entries(inode, eh, &pblk, depth)) {
 		error_msg = "invalid extent entries";
 		goto corrupted;
 	}
-- 
2.35.1.473.g83b2b277ed-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-02-20 14:51 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-02-17 22:59 [PATCH for 5.4 1/3] ext4: check for out-of-order index extents in ext4_valid_extent_entries() Leah Rumancik
2022-02-17 22:59 ` [PATCH for 5.4 2/3] ext4: check for inconsistent extents between index and leaf block Leah Rumancik
2022-02-17 22:59 ` [PATCH for 5.4 3/3] ext4: prevent partial update of the extent blocks Leah Rumancik
2022-02-18  9:21 ` [PATCH for 5.4 1/3] ext4: check for out-of-order index extents in ext4_valid_extent_entries() Greg KH
2022-02-18 19:57   ` Theodore Ts'o
2022-02-20 14:51     ` Greg KH

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