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authorShreyansh Chouhan <chouhan.shreyansh630@gmail.com>2021-07-09 20:59:29 +0530
committerJan Kara <jack@suse.cz>2021-07-16 12:36:51 +0200
commit13d257503c0930010ef9eed78b689cec417ab741 (patch)
tree344d619cbd3944e9aacfc02e54a807b7b1ddcc41 /fs/reiserfs
parent728d392f8a799f037812d0f2b254fb3b5e115fcf (diff)
reiserfs: check directory items on read from disk
While verifying the leaf item that we read from the disk, reiserfs doesn't check the directory items, this could cause a crash when we read a directory item from the disk that has an invalid deh_location. This patch adds a check to the directory items read from the disk that does a bounds check on deh_location for the directory entries. Any directory entry header with a directory entry offset greater than the item length is considered invalid. Link: https://lore.kernel.org/r/20210709152929.766363-1-chouhan.shreyansh630@gmail.com Reported-by: syzbot+c31a48e6702ccb3d64c9@syzkaller.appspotmail.com Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/reiserfs')
-rw-r--r--fs/reiserfs/stree.c31
1 files changed, 26 insertions, 5 deletions
diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c
index 476a7ff49482..ef42729216d1 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -387,6 +387,24 @@ void pathrelse(struct treepath *search_path)
search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
}
+static int has_valid_deh_location(struct buffer_head *bh, struct item_head *ih)
+{
+ struct reiserfs_de_head *deh;
+ int i;
+
+ deh = B_I_DEH(bh, ih);
+ for (i = 0; i < ih_entry_count(ih); i++) {
+ if (deh_location(&deh[i]) > ih_item_len(ih)) {
+ reiserfs_warning(NULL, "reiserfs-5094",
+ "directory entry location seems wrong %h",
+ &deh[i]);
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
static int is_leaf(char *buf, int blocksize, struct buffer_head *bh)
{
struct block_head *blkh;
@@ -454,11 +472,14 @@ static int is_leaf(char *buf, int blocksize, struct buffer_head *bh)
"(second one): %h", ih);
return 0;
}
- if (is_direntry_le_ih(ih) && (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE))) {
- reiserfs_warning(NULL, "reiserfs-5093",
- "item entry count seems wrong %h",
- ih);
- return 0;
+ if (is_direntry_le_ih(ih)) {
+ if (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE)) {
+ reiserfs_warning(NULL, "reiserfs-5093",
+ "item entry count seems wrong %h",
+ ih);
+ return 0;
+ }
+ return has_valid_deh_location(bh, ih);
}
prev_location = ih_location(ih);
}