[syzbot] KASAN: slab-out-of-bounds Read in run_unpack

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 38eddeedbbea Merge tag 'io_uring-6.0-2022-09-18' of git://..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=144e5144880000
kernel config: https://syzkaller.appspot.com/x/.config?x=98a30118ec9215e9
dashboard link: https://syzkaller.appspot.com/bug?extid=8d6fbb27a6aded64b25b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13cee66f080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10fa23bf080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8d6fbb...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 4119
ntfs3: loop0: Different NTFS' sector size (2048) and media sector size (512)
==================================================================
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

CPU: 0 PID: 3611 Comm: syz-executor131 Not tainted 6.0.0-rc5-syzkaller-00097-g38eddeedbbea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
<TASK>
__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
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f94002c539a
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff9faa50f8 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff9faa5150 RCX: 00007f94002c539a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff9faa5110
RBP: 00007fff9faa5110 R08: 00007fff9faa5150 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000020000338
R13: 0000000000000003 R14: 0000000000000004 R15: 000000000000000d
</TASK>

Allocated by task 3184:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:437 [inline]
____kasan_kmalloc mm/kasan/common.c:516 [inline]
____kasan_kmalloc mm/kasan/common.c:475 [inline]
__kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525
kmalloc include/linux/slab.h:600 [inline]
rtnl_newlink+0x46/0xa0 net/core/rtnetlink.c:3589
rtnetlink_rcv_msg+0x43a/0xca0 net/core/rtnetlink.c:6090
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:734
____sys_sendmsg+0x6eb/0x810 net/socket.c:2482
___sys_sendmsg+0x110/0x1b0 net/socket.c:2536
__sys_sendmsg+0xf3/0x1c0 net/socket.c:2565
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88801bbdf000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1794 bytes to the right of
2048-byte region [ffff88801bbdf000, ffff88801bbdf800)

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)
raw: 00fff00000010200 ffffea00005da800 dead000000000002 ffff888011842000
raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 5567869789, free_ts 0
prep_new_page mm/page_alloc.c:2532 [inline]
get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283
__alloc_pages+0x1c7/0x510 mm/page_alloc.c:5515
alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2103
alloc_pages+0x22f/0x270 mm/mempolicy.c:2265
alloc_slab_page mm/slub.c:1824 [inline]
allocate_slab+0x27e/0x3d0 mm/slub.c:1969
new_slab mm/slub.c:2029 [inline]
___slab_alloc+0x7f1/0xe10 mm/slub.c:3031
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
slab_alloc_node mm/slub.c:3209 [inline]
slab_alloc mm/slub.c:3251 [inline]
kmem_cache_alloc_trace+0x323/0x3e0 mm/slub.c:3282
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
virtio_pci_probe+0x44/0x410 drivers/virtio/virtio_pci_common.c:524
local_pci_probe+0xe1/0x1a0 drivers/pci/pci-driver.c:324
pci_call_probe drivers/pci/pci-driver.c:392 [inline]
__pci_device_probe drivers/pci/pci-driver.c:417 [inline]
pci_device_probe+0x298/0x740 drivers/pci/pci-driver.c:460
call_driver_probe drivers/base/dd.c:560 [inline]
really_probe+0x249/0xb90 drivers/base/dd.c:639
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:778
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:808
__driver_attach+0x1d0/0x550 drivers/base/dd.c:1190
bus_for_each_dev+0x147/0x1d0 drivers/base/bus.c:301
page_owner free stack trace missing

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
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Hawkins Jiawei]

It seems that run array offset is out-of-bounds

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 51363d4e8636..edeee31df3c5 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -365,6 +365,10 @@ static struct inode *ntfs_read_mft(struct inode *inode,
roff = le16_to_cpu(attr->nres.run_off);

t64 = le64_to_cpu(attr->nres.svcn);
+
+ if (roff > asize)
+ 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)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+8d6fbb...@syzkaller.appspotmail.com

Tested on:

commit: bf682942 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=15dcd888880000
kernel config: https://syzkaller.appspot.com/x/.config?x=122d7bd4fc8e0ecb

dashboard link: https://syzkaller.appspot.com/bug?extid=8d6fbb27a6aded64b25b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=1476e5b0880000

Note: testing is done by a robot and is best-effort only.

[Hawkins Jiawei]

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:
<TASK>
__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
entry_SYSCALL_64_after_hwframe+0x63/0xcd

[...]
</TASK>

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
ntfs_read_mft().

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 <yin3...@gmail.com>
---
fs/ntfs3/inode.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 51363d4e8636..443a32f789ff 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -365,6 +365,11 @@ 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)
+ 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)

--
2.25.1

[Hawkins Jiawei]

return -EINVAL when roff is out-of-bounds

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

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;
+ }

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+8d6fbb...@syzkaller.appspotmail.com

Tested on:

commit: bf682942 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

console output: https://syzkaller.appspot.com/x/log.txt?x=13c704ef080000

kernel config: https://syzkaller.appspot.com/x/.config?x=122d7bd4fc8e0ecb
dashboard link: https://syzkaller.appspot.com/bug?extid=8d6fbb27a6aded64b25b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=1476bc18880000

[Hawkins Jiawei]

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:
<TASK>
__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
entry_SYSCALL_64_after_hwframe+0x63/0xcd

[...]
</TASK>

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
ntfs_read_mft().

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.

link: https://lore.kernel.org/all/00000000000091...@google.com/#t
Reported-and-tested-by: syzbot+8d6fbb...@syzkaller.appspotmail.com

Signed-off-by: Hawkins Jiawei <yin3...@gmail.com>
---

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)

--
2.25.1

[Konstantin Komarov]

Thanks for patch, applied!