[merged mm-nonmm-stable] ntfs-check-overflow-when-iterates-attr_records.patch removed from -mm tree

[merged mm-nonmm-stable] ntfs-check-overflow-when-iterates-attr_records.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: ntfs: check overflow when iterating ATTR_RECORDs
has been removed from the -mm tree.  Its filename was
     ntfs-check-overflow-when-iterates-attr_records.patch

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

------------------------------------------------------
From: Hawkins Jiawei <yin31149@gmail.com>
Subject: ntfs: check overflow when iterating ATTR_RECORDs
Date: Thu, 1 Sep 2022 00:09:38 +0800

Kernel iterates over ATTR_RECORDs in mft record in ntfs_attr_find(). 
Because the ATTR_RECORDs are next to each other, kernel can get the next
ATTR_RECORD from end address of current ATTR_RECORD, through current
ATTR_RECORD length field.

The problem is that during iteration, when kernel calculates the end
address of current ATTR_RECORD, kernel may trigger an integer overflow bug
in executing `a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))`.  This
may wrap, leading to a forever iteration on 32bit systems.

This patch solves it by adding some checks on calculating end address
of current ATTR_RECORD during iteration.

Link: https://lkml.kernel.org/r/20220831160935.3409-4-yin31149@gmail.com
Link: https://lore.kernel.org/all/20220827105842.GM2030@kadam/
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: chenxiaosong (A) <chenxiaosong2@huawei.com>
Cc: syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ntfs/attrib.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/fs/ntfs/attrib.c~ntfs-check-overflow-when-iterates-attr_records
+++ a/fs/ntfs/attrib.c
@@ -617,6 +617,14 @@ static int ntfs_attr_find(const ATTR_TYP
 			return -ENOENT;
 		if (unlikely(!a->length))
 			break;
+
+		/* check whether ATTR_RECORD's length wrap */
+		if ((u8 *)a + le32_to_cpu(a->length) < (u8 *)a)
+			break;
+		/* check whether ATTR_RECORD's length is within bounds */
+		if ((u8 *)a + le32_to_cpu(a->length) > mrec_end)
+			break;
+
 		if (a->type != type)
 			continue;
 		/*
_

Patches currently in -mm which might be from yin31149@gmail.com are