2021-07-09 15:31:26

by Shreyansh Chouhan

Subject: [PATCH] reiserfs: check directry 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.

Reported-by: [email protected]
Signed-off-by: Shreyansh Chouhan <[email protected]>
---
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

2021-07-20 07:33:17

by Shreyansh Chouhan

Subject: Re: [PATCH] reiserfs: check directry items on read from disk

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: [email protected]
> Signed-off-by: Shreyansh Chouhan <[email protected]>
> ---
> 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
>

2021-07-26 08:23:16

by Jan Kara

Subject: Re: [PATCH] reiserfs: check directry items on read from disk

Hello!

On Tue 20-07-21 13:01:25, Shreyansh Chouhan wrote:
> Just a ping for reviews/merge since there has been no activity on this patch.

The patch is already in my tree and included in linux-next. I wanted to
send it to Linus before going on vacation but somehow that slipped through.
I'll send it to Linus this week with other fixes I have accumulated. I'm
sorry for the delay.

Honza

> 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: [email protected]
> > Signed-off-by: Shreyansh Chouhan <[email protected]>
> > ---
> > 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
> >
--
Jan Kara <[email protected]>
SUSE Labs, CR

2021-07-29 05:08:21

by Shreyansh Chouhan

Subject: Re: [PATCH] reiserfs: check directry items on read from disk

On Mon, Jul 26, 2021 at 10:20:50AM +0200, Jan Kara wrote:
> Hello!
>
> On Tue 20-07-21 13:01:25, Shreyansh Chouhan wrote:
> > Just a ping for reviews/merge since there has been no activity on this patch.
>
> The patch is already in my tree and included in linux-next. I wanted to
> send it to Linus before going on vacation but somehow that slipped through.
> I'll send it to Linus this week with other fixes I have accumulated. I'm
> sorry for the delay.
>

No worries, also thanks a lot for the merge!

Regards,
Shreyansh Chouhan
> Honza
>
> > 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: [email protected]
> > > Signed-off-by: Shreyansh Chouhan <[email protected]>
> > > ---
> > > 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
> > >
> --
> Jan Kara <[email protected]>
> SUSE Labs, CR