From: Hawkins Jiawei <yin31149@gmail.com>
To: syzbot+5f8dcabe4a3b2c51c607@syzkaller.appspotmail.com,
Anton Altaparmakov <anton@tuxera.com>
Cc: akpm@linux-foundation.org, chenxiaosong2@huawei.com,
linux-kernel@vger.kernel.org,
linux-ntfs-dev@lists.sourceforge.net,
syzkaller-bugs@googlegroups.com, yin31149@gmail.com
Subject: [PATCH] ntfs: change check order in ntfs_attr_find
Date: Fri, 26 Aug 2022 20:27:34 +0800 [thread overview]
Message-ID: <20220826122735.2690-1-yin31149@gmail.com> (raw)
In-Reply-To: <0000000000006886bd05e714ec18@google.com>
syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
Looks like it is improper check order that causes this bug.
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
fs/ntfs/attrib.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 52615e6090e1..6480cd2d371d 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -594,10 +594,11 @@ static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name,
for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) {
u8 *mrec_end = (u8 *)ctx->mrec +
le32_to_cpu(ctx->mrec->bytes_allocated);
+ if ((u8*)a < (u8*)ctx->mrec || (u8*)a > mrec_end)
+ break;
u8 *name_end = (u8 *)a + le16_to_cpu(a->name_offset) +
a->name_length * sizeof(ntfschar);
- if ((u8*)a < (u8*)ctx->mrec || (u8*)a > mrec_end ||
- name_end > mrec_end)
+ if (name_end > mrec_end)
break;
ctx->attr = a;
if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) ||
--
2.25.1
next prev parent reply other threads:[~2022-08-26 12:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 18:25 [syzbot] KASAN: use-after-free Read in ntfs_attr_find syzbot
2022-08-25 18:32 ` Siddh Raman Pant
2022-08-25 18:34 ` Siddh Raman Pant
2022-08-26 12:27 ` Hawkins Jiawei [this message]
2022-08-26 12:32 ` [PATCH] ntfs: change check order " Hawkins Jiawei
2022-08-26 14:16 ` [syzbot] KASAN: use-after-free Read " syzbot
2022-08-26 15:15 ` [PATCH] ntfs: change check order " Dan Carpenter
2022-08-26 15:42 ` Hawkins Jiawei
2022-08-26 15:54 ` Hawkins Jiawei
2022-08-27 6:42 ` Dan Carpenter
2022-08-27 9:02 ` Hawkins Jiawei
2022-08-27 10:58 ` Dan Carpenter
2022-08-28 16:15 ` Hawkins Jiawei
2022-08-27 2:42 ` Andrew Morton
2022-08-27 8:38 ` Hawkins Jiawei
2022-08-27 1:28 ` chenxiaosong (A)
2022-08-27 7:51 ` Hawkins Jiawei
2022-08-27 14:49 ` Hawkins Jiawei
2022-08-29 9:51 ` Dan Carpenter
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