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| author | Hawkins Jiawei <yin31149@gmail.com> | 2022-08-31 18:09:38 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-12 06:55:12 +0200 |
| commit | 63095f4f3af59322bea984a6ae44337439348fe0 (patch) | |
| tree | 27fcd939c7ce47e02a3f844d77244da0f75f5403 /fs/ntfs | |
| parent | ntfs: fix out-of-bounds read in ntfs_attr_find() (diff) | |
| download | linux-63095f4f3af59322bea984a6ae44337439348fe0.tar.xz linux-63095f4f3af59322bea984a6ae44337439348fe0.zip | |
ntfs: check overflow when iterating ATTR_RECORDs
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>
Diffstat (limited to 'fs/ntfs')
| -rw-r--r-- | fs/ntfs/attrib.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c index cec4be2a2d23..a3865bc4a0c6 100644 --- a/fs/ntfs/attrib.c +++ b/fs/ntfs/attrib.c @@ -617,6 +617,14 @@ static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name, 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; /* |