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* [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref
@ 2022-10-03 22:45 FirstName LastName
  2022-10-04 12:53 ` Alexey Dobriyan
  2022-10-04 18:46 ` Andrew Morton
  0 siblings, 2 replies; 4+ messages in thread
From: FirstName LastName @ 2022-10-03 22:45 UTC (permalink / raw)
  To: Andrew Morton, linux-fsdevel
  Cc: linux-kernel, Alexey Dobriyan, Vlastimil Babka, Seth Jenkins,
	Jann Horn, linux-mm, stable

From: Seth Jenkins <sethjenkins@google.com>

Commit 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value
seq_file") introduced a null-deref if there are no vma's in the task in
show_smaps_rollup.

Fixes: 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value seq_file")
Cc: stable@vger.kernel.org
Signed-off-by: Seth Jenkins <sethjenkins@google.com>
---
 fs/proc/task_mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 4e0023643f8b..1e7bbc0873a4 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -969,7 +969,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 		vma = vma->vm_next;
 	}
 
-	show_vma_header_prefix(m, priv->mm->mmap->vm_start,
+	show_vma_header_prefix(m, priv->mm->mmap ? priv->mm->mmap->vm_start : 0,
 			       last_vma_end, 0, 0, 0, 0);
 	seq_pad(m, ' ');
 	seq_puts(m, "[rollup]\n");
-- 
2.38.0.rc1.362.ged0d419d3c-goog


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref
  2022-10-03 22:45 [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref FirstName LastName
@ 2022-10-04 12:53 ` Alexey Dobriyan
  2022-10-04 18:46 ` Andrew Morton
  1 sibling, 0 replies; 4+ messages in thread
From: Alexey Dobriyan @ 2022-10-04 12:53 UTC (permalink / raw)
  To: sethjenkins
  Cc: Andrew Morton, linux-fsdevel, linux-kernel, Vlastimil Babka,
	Jann Horn, linux-mm, stable

On Mon, Oct 03, 2022 at 06:45:31PM -0400, FirstName LastName wrote:
> From: Seth Jenkins <sethjenkins@google.com>
> 
> Commit 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value
> seq_file") introduced a null-deref if there are no vma's in the task in
> show_smaps_rollup.
> 
> Fixes: 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value seq_file")
> Cc: stable@vger.kernel.org
> Signed-off-by: Seth Jenkins <sethjenkins@google.com>

> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -969,7 +969,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
>  		vma = vma->vm_next;
>  	}
>  
> -	show_vma_header_prefix(m, priv->mm->mmap->vm_start,
> +	show_vma_header_prefix(m, priv->mm->mmap ? priv->mm->mmap->vm_start : 0,
>  			       last_vma_end, 0, 0, 0, 0);
>  	seq_pad(m, ' ');
>  	seq_puts(m, "[rollup]\n");

Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Tested-by: Alexey Dobriyan <adobriyan@gmail.com>

Now I know how to create stable process without address space.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref
  2022-10-03 22:45 [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref FirstName LastName
  2022-10-04 12:53 ` Alexey Dobriyan
@ 2022-10-04 18:46 ` Andrew Morton
  2022-10-04 21:05   ` Seth Jenkins
  1 sibling, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2022-10-04 18:46 UTC (permalink / raw)
  To: FirstName LastName
  Cc: linux-fsdevel, linux-kernel, Alexey Dobriyan, Vlastimil Babka,
	Jann Horn, linux-mm, stable

On Mon,  3 Oct 2022 18:45:31 -0400 FirstName LastName <sethjenkins@google.com> wrote:

> From: Seth Jenkins <sethjenkins@google.com>
> 
> Commit 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value
> seq_file") introduced a null-deref if there are no vma's in the task in
> show_smaps_rollup.
> 
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -969,7 +969,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
>  		vma = vma->vm_next;
>  	}
>  
> -	show_vma_header_prefix(m, priv->mm->mmap->vm_start,
> +	show_vma_header_prefix(m, priv->mm->mmap ? priv->mm->mmap->vm_start : 0,
>  			       last_vma_end, 0, 0, 0, 0);
>  	seq_pad(m, ' ');
>  	seq_puts(m, "[rollup]\n");

The current mm tree is very different here.  In fact the bug might not
exist any more.  Please take a look at the mm-stable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm?

If no fixes are needed in mm-stable then I guess the process is to
propose this patch to the stable tree maintainers.


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref
  2022-10-04 18:46 ` Andrew Morton
@ 2022-10-04 21:05   ` Seth Jenkins
  0 siblings, 0 replies; 4+ messages in thread
From: Seth Jenkins @ 2022-10-04 21:05 UTC (permalink / raw)
  To: Andrew Morton
  Cc: linux-fsdevel, linux-kernel, Alexey Dobriyan, Vlastimil Babka,
	Jann Horn, linux-mm, stable

I concur, mm-stable looks fine to me as well.

Jann and I conversed today and the tentative decision since this isn't
considered a high-priority security bug is to wait for maple tree to
merge into Linus's branch before submitting this patch to stable.

On Tue, Oct 4, 2022 at 2:46 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Mon,  3 Oct 2022 18:45:31 -0400 FirstName LastName <sethjenkins@google.com> wrote:
>
> > From: Seth Jenkins <sethjenkins@google.com>
> >
> > Commit 258f669e7e88 ("mm: /proc/pid/smaps_rollup: convert to single value
> > seq_file") introduced a null-deref if there are no vma's in the task in
> > show_smaps_rollup.
> >
> > --- a/fs/proc/task_mmu.c
> > +++ b/fs/proc/task_mmu.c
> > @@ -969,7 +969,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
> >               vma = vma->vm_next;
> >       }
> >
> > -     show_vma_header_prefix(m, priv->mm->mmap->vm_start,
> > +     show_vma_header_prefix(m, priv->mm->mmap ? priv->mm->mmap->vm_start : 0,
> >                              last_vma_end, 0, 0, 0, 0);
> >       seq_pad(m, ' ');
> >       seq_puts(m, "[rollup]\n");
>
> The current mm tree is very different here.  In fact the bug might not
> exist any more.  Please take a look at the mm-stable branch at
> git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm?
>
> If no fixes are needed in mm-stable then I guess the process is to
> propose this patch to the stable tree maintainers.
>

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-10-04 21:06 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-10-03 22:45 [PATCH] mm: /proc/pid/smaps_rollup: fix no vma's null-deref FirstName LastName
2022-10-04 12:53 ` Alexey Dobriyan
2022-10-04 18:46 ` Andrew Morton
2022-10-04 21:05   ` Seth Jenkins

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