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[2/3] btrfs: Check if item pointer overlap with item itself

Message ID 20170822073717.13081-3-quwenruo.btrfs@gmx.com (mailing list archive)
State New, archived
Headers show

Commit Message

Qu Wenruo Aug. 22, 2017, 7:37 a.m. UTC 
Function check_leaf() checks if any item pointer points outside of the
leaf, but it doesn't check if the pointer overlap with the item itself.

Normally only the last item may be the victim, but add such check is
never a bad idea anyway.

Signed-off-by: Qu Wenruo <quwenruo.btrfs@gmx.com>
---
 fs/btrfs/disk-io.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff mbox

Patch

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 919ddd4b774c..59ee7b959bf0 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -643,6 +643,13 @@  static noinline int check_leaf(struct btrfs_root *root,
 			return -EIO;
 		}
 
+		/* Also check if the item pointer overlaps with btrfs item. */
+		if (btrfs_item_nr_offset(slot) + sizeof(struct btrfs_item) >
+		    btrfs_item_ptr_offset(leaf, slot)) {
+			CORRUPT("slot overlap with its data", leaf, root, slot);
+			return -EIO;
+		}
+
 		prev_key.objectid = key.objectid;
 		prev_key.type = key.type;
 		prev_key.offset = key.offset;