lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Fri, 23 Sep 2022 19:09:04 +0800
From:   Hawkins Jiawei <>
        Konstantin Komarov <>
Subject: [PATCH v2] fs/ntfs3: fix slab-out-of-bounds Read in run_unpack

Syzkaller reports slab-out-of-bounds bug as follows:
BUG: KASAN: slab-out-of-bounds in run_unpack+0x8b7/0x970 fs/ntfs3/run.c:944
Read of size 1 at addr ffff88801bbdff02 by task syz-executor131/3611

Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
 run_unpack+0x8b7/0x970 fs/ntfs3/run.c:944
 run_unpack_ex+0xb0/0x7c0 fs/ntfs3/run.c:1057
 ntfs_read_mft fs/ntfs3/inode.c:368 [inline]
 ntfs_iget5+0xc20/0x3280 fs/ntfs3/inode.c:501
 ntfs_loadlog_and_replay+0x124/0x5d0 fs/ntfs3/fsntfs.c:272
 ntfs_fill_super+0x1eff/0x37f0 fs/ntfs3/super.c:1018
 get_tree_bdev+0x440/0x760 fs/super.c:1323
 vfs_get_tree+0x89/0x2f0 fs/super.c:1530
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1326/0x1e20 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80

The buggy address belongs to the physical page:
page:ffffea00006ef600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1bbd8
head:ffffea00006ef600 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88801bbdfe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801bbdfe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801bbdff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801bbdff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801bbe0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Kernel will tries to read record and parse MFT from disk in

Yet the problem is that during enumerating attributes in record,
kernel doesn't check whether run_off field loading from the disk
is a valid value.

To be more specific, if attr->nres.run_off is larger than attr->size,
kernel will passes an invalid argument run_buf_size in
run_unpack_ex(), which having an integer overflow. Then this invalid
argument will triggers the slab-out-of-bounds Read bug as above.

This patch solves it by adding the sanity check between
the offset to packed runs and attribute size.

Signed-off-by: Hawkins Jiawei <>
v1 -> v2:
  return -EINVAL when roff is out-of-bounds

 fs/ntfs3/inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 51363d4e8636..10723231e482 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -365,6 +365,13 @@ static struct inode *ntfs_read_mft(struct inode *inode,
 	roff = le16_to_cpu(attr->nres.run_off);
 	t64 = le64_to_cpu(attr->nres.svcn);
+	/* offset to packed runs is out-of-bounds */
+	if (roff > asize) {
+		err = -EINVAL;
+		goto out;
+	}
 	err = run_unpack_ex(run, sbi, ino, t64, le64_to_cpu(attr->nres.evcn),
 			    t64, Add2Ptr(attr, roff), asize - roff);
 	if (err < 0)

Powered by blists - more mailing lists