The patch titled
Subject: maple_tree: fix potential out-of-bounds access in mas_wr_end_piv()
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-fix-potential-out-of-bounds-access-in-mas_wr_end_piv.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-fix-potential-out-of-bounds-access-in-mas_wr_end_piv.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Subject: maple_tree: fix potential out-of-bounds access in mas_wr_end_piv()
Date: Sat, 6 May 2023 10:47:52 +0800
Check the write offset end bounds before using it as the offset into the
pivot array. This avoids a possible out-of-bounds access on the pivot
array if the write extends to the last slot in the node, in which case the
node maximum should be used as the end pivot.
akpm: this doesn't affect any current callers, but new users of mapletree
may encounter this problem if backported into earlier kernels, so let's
fix it in -stable kernels in case of this.
Link: https://lkml.kernel.org/r/20230506024752.2550-1-zhangpeng.00@xxxxxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/lib/maple_tree.c~maple_tree-fix-potential-out-of-bounds-access-in-mas_wr_end_piv
+++ a/lib/maple_tree.c
@@ -4262,11 +4262,13 @@ done:
static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas)
{
- while ((wr_mas->mas->last > wr_mas->end_piv) &&
- (wr_mas->offset_end < wr_mas->node_end))
- wr_mas->end_piv = wr_mas->pivots[++wr_mas->offset_end];
+ while ((wr_mas->offset_end < wr_mas->node_end) &&
+ (wr_mas->mas->last > wr_mas->pivots[wr_mas->offset_end]))
+ wr_mas->offset_end++;
- if (wr_mas->mas->last > wr_mas->end_piv)
+ if (wr_mas->offset_end < wr_mas->node_end)
+ wr_mas->end_piv = wr_mas->pivots[wr_mas->offset_end];
+ else
wr_mas->end_piv = wr_mas->mas->max;
}
@@ -4423,7 +4425,6 @@ static inline void *mas_wr_store_entry(s
}
/* At this point, we are at the leaf node that needs to be altered. */
- wr_mas->end_piv = wr_mas->r_max;
mas_wr_end_piv(wr_mas);
if (!wr_mas->entry)
_
Patches currently in -mm which might be from zhangpeng.00@xxxxxxxxxxxxx are
maple_tree-make-maple-state-reusable-after-mas_empty_area.patch
maple_tree-fix-potential-out-of-bounds-access-in-mas_wr_end_piv.patch
