Hi,
Just a ping for reviews/merge since there has been no activity on this patch.
Thank you,
Shreyansh Chouhan
On Fri, Jul 09, 2021 at 08:59:29PM +0530, Shreyansh Chouhan wrote:
>
> 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.
>
> Reported-by: syzbot+c31a48e6702ccb3d64c9@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@xxxxxxxxx>
> ---
> fs/reiserfs/stree.c | 31 ++++++++++++++++++++++++++-----
> 1 file 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);
> }
> --
> 2.31.1
>
