[PATCH] lib/ext2fs: Validity checks for ext2fs_inode_scan_goto_blockgroup()

Brian Norris
2023-12-01T00:01:32Z

We don't validate the 'group' argument, so it's easy to get underflows
or crashes here.

This resolves issues seen in ureadahead, when it uses an old packfile
(with mismatching group indices) with a new filesystem.

Signed-off-by: Brian Norris <briannorris@chromium.org>
---

lib/ext2fs/inode.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
index 957d5aa9f9d6..96d854b5fb69 100644
--- a/lib/ext2fs/inode.c
+++ b/lib/ext2fs/inode.c
@@ -313,6 +313,9 @@ static errcode_t get_next_blockgroup(ext2_inode_scan scan)
errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
int group)
{
+ if (group <= 0 || group >= scan->fs->group_desc_count)
+ return EXT2_ET_INVALID_ARGUMENT;
+
scan->current_group = group - 1;
scan->groups_left = scan->fs->group_desc_count - group;
scan->bad_block_ptr = 0;
--
2.43.0.rc2.451.g8631bc7472-goog