57 lines
1.8 KiB
Diff
57 lines
1.8 KiB
Diff
|
From 265fcf9204fd06f574578ebe780f24e62bac2e86 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Lukas Czerner <lczerner@redhat.com>
|
||
|
|
Date: Thu, 21 Apr 2022 19:31:48 +0200
|
||
|
|
Subject: [PATCH 1/2] libext2fs: add sanity check to extent manipulation
|
||
|
|
Content-Type: text/plain
|
||
|
|
|
||
|
|
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 <lczerner@redhat.com>
|
||
|
|
Reported-by: Nils Bars <nils_bars@t-online.de>
|
||
|
|
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2068113
|
||
|
|
Addresses: CVE-2022-1304
|
||
|
|
Addresses-Debian-Bug: #1010263
|
||
|
|
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
|
||
|
|
---
|
||
|
|
lib/ext2fs/extent.c | 8 ++++++++
|
||
|
|
1 file changed, 8 insertions(+)
|
||
|
|
|
||
|
|
diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
|
||
|
|
index ac3dbfec..a1b1905c 100644
|
||
|
|
--- 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_extent_handle_t handle, int flags)
|
||
|
|
|
||
|
|
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));
|
||
|
|
--
|
||
|
|
2.35.1
|
||
|
|
|