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From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Pengfei Xu <pengfei.xu@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Suren Baghdasaryan <surenb@google.com>,
	Matthew Wilcox <willy@infradead.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	sidhartha.kumar@oracle.com, Bert Karwatzki <spasswolf@web.de>,
	Jiri Olsa <olsajiri@gmail.com>, Kees Cook <kees@kernel.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Jeff Xu <jeffxu@chromium.org>,
	syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH v8 15/21] mm: Change failure of MAP_FIXED to restoring the gap on failure
Date: Tue, 3 Sep 2024 12:03:25 -0400	[thread overview]
Message-ID: <atepi7eatm6dkmybou7dsyxg5c7mrlpuhfom45xzug7lqoexc2@kwk2avbfa3vl> (raw)
In-Reply-To: <52ee7eb3-955c-4ade-b5f0-28fed8ba3d0b@lucifer.local>

* Lorenzo Stoakes <lorenzo.stoakes@oracle.com> [240903 08:27]:
> Hi Andrew - TL;DR of this is - please apply the fix patch attached below to
> fix a problem in this series, thanks! :)

Oh yes.  I should have caught this, thanks Lorenzo.

Cheers,
Liam


> ----8<----
> From 3e7decc5390b0edc462afa74794a8208e25e50f2 Mon Sep 17 00:00:00 2001
> From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Date: Tue, 3 Sep 2024 13:20:34 +0100
> Subject: [PATCH] mm: fix off-by-one error in vms_abort_munmap_vmas()
> 
> Maple tree ranges have an inclusive end, VMAs do not, so we must subtract
> one from the VMA-specific end value when using a mas_...() function.
> 
> We failed to do so in vms_abort_munmap_vmas() which resulted in a store
> overlapping the intended range by one byte, and thus corrupting the maple
> tree.
> 
> Fix this by subtracting one from vms->end() passed into mas_set_range().
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
>  mm/vma.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vma.h b/mm/vma.h
> index 370d3246f147..819f994cf727 100644
> --- a/mm/vma.h
> +++ b/mm/vma.h
> @@ -240,7 +240,7 @@ static inline void vms_abort_munmap_vmas(struct vma_munmap_struct *vms,
>  	 * not symmetrical and state data has been lost.  Resort to the old
>  	 * failure method of leaving a gap where the MAP_FIXED mapping failed.
>  	 */
> -	mas_set_range(mas, vms->start, vms->end);
> +	mas_set_range(mas, vms->start, vms->end - 1);
>  	if (unlikely(mas_store_gfp(mas, NULL, GFP_KERNEL))) {
>  		pr_warn_once("%s: (%d) Unable to abort munmap() operation\n",
>  			     current->comm, current->pid);
> --
> 2.46.0


  reply	other threads:[~2024-09-03 16:03 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-30  4:00 [PATCH v8 00/21] Avoid MAP_FIXED gap exposure Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 01/21] mm/vma: Correctly position vma_iterator in __split_vma() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 02/21] mm/vma: Introduce abort_munmap_vmas() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 03/21] mm/vma: Introduce vmi_complete_munmap_vmas() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 04/21] mm/vma: Extract the gathering of vmas from do_vmi_align_munmap() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 05/21] mm/vma: Introduce vma_munmap_struct for use in munmap operations Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 06/21] mm/vma: Change munmap to use vma_munmap_struct() for accounting and surrounding vmas Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 07/21] mm/vma: Extract validate_mm() from vma_complete() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 08/21] mm/vma: Inline munmap operation in mmap_region() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 09/21] mm/vma: Expand mmap_region() munmap call Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 10/21] mm/vma: Support vma == NULL in init_vma_munmap() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 11/21] mm/mmap: Reposition vma iterator in mmap_region() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 12/21] mm/vma: Track start and end for munmap in vma_munmap_struct Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 13/21] mm: Clean up unmap_region() argument list Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 14/21] mm/mmap: Avoid zeroing vma tree in mmap_region() Liam R. Howlett
2024-10-07 19:05   ` [BUG] page table UAF, " Jann Horn
2024-10-07 20:31     ` Liam R. Howlett
2024-10-07 21:31       ` Jann Horn
2024-10-08  1:50         ` Liam R. Howlett
2024-10-08 17:15           ` Jann Horn
2024-10-08 17:51             ` Suren Baghdasaryan
2024-10-08 18:06               ` Jann Horn
2024-10-11 14:26             ` Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 15/21] mm: Change failure of MAP_FIXED to restoring the gap on failure Liam R. Howlett
2024-09-03  3:07   ` Pengfei Xu
2024-09-03 11:00     ` Lorenzo Stoakes
2024-09-03 12:27       ` Lorenzo Stoakes
2024-09-03 16:03         ` Liam R. Howlett [this message]
2024-08-30  4:00 ` [PATCH v8 16/21] mm/mmap: Use PHYS_PFN in mmap_region() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 17/21] mm/mmap: Use vms accounted pages " Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 18/21] ipc/shm, mm: Drop do_vma_munmap() Liam R. Howlett
2024-08-30  4:00 ` [PATCH v8 19/21] mm: Move may_expand_vm() check in mmap_region() Liam R. Howlett
2024-08-30  4:01 ` [PATCH v8 20/21] mm/vma: Drop incorrect comment from vms_gather_munmap_vmas() Liam R. Howlett
2024-08-30  4:01 ` [PATCH v8 21/21] mm/vma.h: Optimise vma_munmap_struct Liam R. Howlett
2024-08-30 16:05 ` [PATCH v8 00/21] Avoid MAP_FIXED gap exposure Jeff Xu
2024-08-30 17:07   ` Liam R. Howlett

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