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* [merged mm-stable] mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch removed from -mm tree
@ 2025-07-25  2:14 Andrew Morton
  0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2025-07-25  2:14 UTC (permalink / raw)
  To: mm-commits, stable, kasong, hannes, bhe, shikemeng, akpm


The quilt patch titled
     Subject: mm: swap: fix potential buffer overflow in setup_clusters()
has been removed from the -mm tree.  Its filename was
     mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Kemeng Shi <shikemeng@huaweicloud.com>
Subject: mm: swap: fix potential buffer overflow in setup_clusters()
Date: Thu, 22 May 2025 20:25:53 +0800

In setup_swap_map(), we only ensure badpages are in range (0, last_page]. 
As maxpages might be < last_page, setup_clusters() will encounter a buffer
overflow when a badpage is >= maxpages.

Only call inc_cluster_info_page() for badpage which is < maxpages to fix
the issue.

Link: https://lkml.kernel.org/r/20250522122554.12209-4-shikemeng@huaweicloud.com
Fixes: b843786b0bd0 ("mm: swapfile: fix SSD detection with swapfile on btrfs")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swapfile.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/mm/swapfile.c~mm-swap-fix-potensial-buffer-overflow-in-setup_clusters
+++ a/mm/swapfile.c
@@ -3208,9 +3208,13 @@ static struct swap_cluster_info *setup_c
 	 * and the EOF part of the last cluster.
 	 */
 	inc_cluster_info_page(si, cluster_info, 0);
-	for (i = 0; i < swap_header->info.nr_badpages; i++)
-		inc_cluster_info_page(si, cluster_info,
-				      swap_header->info.badpages[i]);
+	for (i = 0; i < swap_header->info.nr_badpages; i++) {
+		unsigned int page_nr = swap_header->info.badpages[i];
+
+		if (page_nr >= maxpages)
+			continue;
+		inc_cluster_info_page(si, cluster_info, page_nr);
+	}
 	for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++)
 		inc_cluster_info_page(si, cluster_info, i);
 
_

Patches currently in -mm which might be from shikemeng@huaweicloud.com are



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