[PATCH] ntfs: Fix attribute validation check

[PATCH] ntfs: Fix attribute validation check

[Vladimir Serbinenko]

Without this fix GRUB doesn't see most of the files
on NTFS partition.

Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
---
 grub-core/fs/ntfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
index b3117bf92..393a763ee 100644
--- a/grub-core/fs/ntfs.c
+++ b/grub-core/fs/ntfs.c
@@ -175,7 +175,7 @@ validate_attribute (grub_uint8_t *attr, void *end)
 	   * the minimum size.
 	   */
 	  min_size += (attr[curr] & 0x7) + ((attr[curr] >> 4) & 0x7);
-	  curr += min_size;
+	  curr = min_size;
 	  min_size++;
 	  if (min_size > attr_size)
 	    goto fail;
-- 
2.49.0


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Re: [PATCH] ntfs: Fix attribute validation check

[Glenn Washburn]

On Sat,  3 May 2025 08:02:07 +0000
Vladimir Serbinenko <phcoder@gmail.com> wrote:

> Without this fix GRUB doesn't see most of the files
> on NTFS partition.

I can confirm that this fixes the testing issue I mentioned in another
thread. The ntfs filesystem tests now fail with HARDLINK FAIL, but I
presume that's a separate issue.

Tested-by: Glenn Washburn <development@efficientek.com>

Glenn

> 
> Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
> ---
>  grub-core/fs/ntfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
> index b3117bf92..393a763ee 100644
> --- a/grub-core/fs/ntfs.c
> +++ b/grub-core/fs/ntfs.c
> @@ -175,7 +175,7 @@ validate_attribute (grub_uint8_t *attr, void *end)
>  	   * the minimum size.
>  	   */
>  	  min_size += (attr[curr] & 0x7) + ((attr[curr] >> 4) & 0x7);
> -	  curr += min_size;
> +	  curr = min_size;
>  	  min_size++;
>  	  if (min_size > attr_size)
>  	    goto fail;

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Re: [PATCH] ntfs: Fix attribute validation check

[Andrew Hamilton]

[-- Attachment #1.1: Type: text/plain, Size: 1534 bytes --]

Yes this matches with the first layer of the onion I also found.

The hard link fail issue seems to stem from attempting to use
validate_attribute on attribute lists instead of attributes, I’m working on
a fix for that but it’s taking some time as it creates new fuzzer
identified flaws once changed.

Thanks
Andrew

On Mon, May 5, 2025 at 10:22 AM Glenn Washburn <development@efficientek.com>
wrote:

> On Sat,  3 May 2025 08:02:07 +0000
> Vladimir Serbinenko <phcoder@gmail.com> wrote:
>
> > Without this fix GRUB doesn't see most of the files
> > on NTFS partition.
>
> I can confirm that this fixes the testing issue I mentioned in another
> thread. The ntfs filesystem tests now fail with HARDLINK FAIL, but I
> presume that's a separate issue.
>
> Tested-by: Glenn Washburn <development@efficientek.com>
>
> Glenn
>
> >
> > Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
> > ---
> >  grub-core/fs/ntfs.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
> > index b3117bf92..393a763ee 100644
> > --- a/grub-core/fs/ntfs.c
> > +++ b/grub-core/fs/ntfs.c
> > @@ -175,7 +175,7 @@ validate_attribute (grub_uint8_t *attr, void *end)
> >          * the minimum size.
> >          */
> >         min_size += (attr[curr] & 0x7) + ((attr[curr] >> 4) & 0x7);
> > -       curr += min_size;
> > +       curr = min_size;
> >         min_size++;
> >         if (min_size > attr_size)
> >           goto fail;
>

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Re: [PATCH] ntfs: Fix attribute validation check

[Daniel Kiper]

On Sat, May 03, 2025 at 08:02:07AM +0000, Vladimir Serbinenko wrote:
> Without this fix GRUB doesn't see most of the files
> on NTFS partition.

It would be perfect if it is explained why current code is broken and
why the fix is correct...

Daniel

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Re: [PATCH] ntfs: Fix attribute validation check

[Andrew Hamilton]

[-- Attachment #1.1: Type: text/plain, Size: 742 bytes --]

I just sent a patch series that happens to attempt to address the same
issue being addressed here, but in a slightly different way. It should have
title:
[PATCH 1/3] fs/ntfs: Correct some NTFS regressions


Thanks,
Andrew

On Thu, May 15, 2025 at 11:25 AM Daniel Kiper <dkiper@net-space.pl> wrote:

> On Sat, May 03, 2025 at 08:02:07AM +0000, Vladimir Serbinenko wrote:
> > Without this fix GRUB doesn't see most of the files
> > on NTFS partition.
>
> It would be perfect if it is explained why current code is broken and
> why the fix is correct...
>
> Daniel
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
>

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