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From:   Hawkins Jiawei <yin31149@gmail.com>
To:     syzbot+8d6fbb27a6aded64b25b@syzkaller.appspotmail.com
Cc:     almaz.alexandrovich@paragon-software.com,
        linux-kernel@vger.kernel.org, ntfs3@lists.linux.dev,
        syzkaller-bugs@googlegroups.com, 18801353760@163.com,
        yin31149@gmail.com
Subject: Re: [syzbot] KASAN: slab-out-of-bounds Read in run_unpack
Date:   Fri, 23 Sep 2022 11:17:22 +0800
Message-Id: <20220923031722.3744-1-yin31149@gmail.com>
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> 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+8d6fbb27a6aded64b25b@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
> ==================================================================

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)