| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950 |
- From ab51d587bb9b229b1fade1afd02e1574c1ba5c76 Mon Sep 17 00:00:00 2001
- From: Lukas Czerner <[email protected]>
- Date: Thu, 21 Apr 2022 19:31:48 +0200
- Subject: libext2fs: add sanity check to extent manipulation
- It is possible to have a corrupted extent tree in such a way that a leaf
- node contains zero extents in it. Currently if that happens and we try
- to traverse the tree we can end up accessing wrong data, or possibly
- even uninitialized memory. Make sure we don't do that.
- Additionally make sure that we have a sane number of bytes passed to
- memmove() in ext2fs_extent_delete().
- Note that e2fsck is currently unable to spot and fix such corruption in
- pass1.
- Signed-off-by: Lukas Czerner <[email protected]>
- Reported-by: Nils Bars <[email protected]>
- Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2068113
- Addresses: CVE-2022-1304
- Addresses-Debian-Bug: #1010263
- Signed-off-by: Theodore Ts'o <[email protected]>
- ---
- lib/ext2fs/extent.c | 8 ++++++++
- 1 file changed, 8 insertions(+)
- --- a/lib/ext2fs/extent.c
- +++ b/lib/ext2fs/extent.c
- @@ -495,6 +495,10 @@ retry:
- ext2fs_le16_to_cpu(eh->eh_entries);
- newpath->max_entries = ext2fs_le16_to_cpu(eh->eh_max);
-
- + /* Make sure there is at least one extent present */
- + if (newpath->left <= 0)
- + return EXT2_ET_EXTENT_NO_DOWN;
- +
- if (path->left > 0) {
- ix++;
- newpath->end_blk = ext2fs_le32_to_cpu(ix->ei_block);
- @@ -1630,6 +1634,10 @@ errcode_t ext2fs_extent_delete(ext2_exte
-
- cp = path->curr;
-
- + /* Sanity check before memmove() */
- + if (path->left < 0)
- + return EXT2_ET_EXTENT_LEAF_BAD;
- +
- if (path->left) {
- memmove(cp, cp + sizeof(struct ext3_extent_idx),
- path->left * sizeof(struct ext3_extent_idx));
|
