summaryrefslogtreecommitdiff
path: root/fs/ntfs
diff options
context:
space:
mode:
authorHawkins Jiawei <yin31149@gmail.com>2022-08-31 19:09:38 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-09-12 07:55:12 +0300
commit63095f4f3af59322bea984a6ae44337439348fe0 (patch)
tree27fcd939c7ce47e02a3f844d77244da0f75f5403 /fs/ntfs
parent36a4d82dddbbd421d2b8e79e1cab68c8126d5075 (diff)
downloadlinux-63095f4f3af59322bea984a6ae44337439348fe0.tar.xz
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.c8
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;
/*