KASAN: use-after-free Read in ntfs_trim_fs

[Palash Oswal]

Hello,
I found the following issue using syzkaller on:
HEAD commit : e60276b8c11ab4a8be23807bc67b04
8cfb937dfa (v6.0.8)
git tree: stable

C Reproducer : https://gist.github.com/oswalpalash/113c274067bc9c4c653a6dd09fb2e456
Kernel .config :
https://gist.github.com/oswalpalash/0962c70d774e5ec736a047bba917cecb

Console log :

==================================================================
BUG: KASAN: use-after-free in ntfs_trim_fs+0x84e/0x960
Read of size 2 at addr ffff888104fea640 by task syz-executor.0/8081

CPU: 1 PID: 8081 Comm: syz-executor.0 Not tainted 6.0.8-pasta #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xcd/0x134
 print_report.cold+0xe5/0x63a
 kasan_report+0x8a/0x1b0
 ntfs_trim_fs+0x84e/0x960
 ntfs_ioctl_fitrim+0x23e/0x340
 ntfs_ioctl+0x9c/0xd0
 __x64_sys_ioctl+0x193/0x200
 do_syscall_64+0x35/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fac7f88eacd
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48
89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fac805f9bf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fac7f9bbf80 RCX: 00007fac7f88eacd
RDX: 0000000020000040 RSI: 00000000c0185879 RDI: 0000000000000003
RBP: 00007fac7f8fcb05 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcb363e05f R14: 00007ffcb363e200 R15: 00007fac805f9d80
 </TASK>

Allocated by task 8074:
 kasan_save_stack+0x1e/0x40
 __kasan_kmalloc+0xa6/0xd0
 __kmalloc+0x349/0xd40
 tomoyo_encode2.part.0+0xec/0x3b0
 tomoyo_encode+0x28/0x50
 tomoyo_realpath_from_path+0x186/0x620
 tomoyo_path_perm+0x219/0x420
 security_inode_getattr+0xcf/0x140
 vfs_getattr+0x22/0x60
 vfs_fstat+0x49/0x90
 __do_sys_newfstat+0x81/0x100
 do_syscall_64+0x35/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 8074:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 kasan_set_free_info+0x20/0x30
 __kasan_slab_free+0xf5/0x180
 kfree+0x15e/0x540
 tomoyo_path_perm+0x240/0x420
 security_inode_getattr+0xcf/0x140
 vfs_getattr+0x22/0x60
 vfs_fstat+0x49/0x90
 __do_sys_newfstat+0x81/0x100
 do_syscall_64+0x35/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888104fea640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff888104fea640, ffff888104fea660)

The buggy address belongs to the physical page:
page:ffffea000413fa80 refcount:1 mapcount:0 mapping:0000000000000000
index:0xffff888104feafc1 pfn:0x104fea
flags: 0x57ff00000000200(slab|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000200 ffffea00043f1b88 ffffea000414bec8 ffff888011840100
raw: ffff888104feafc1 ffff888104fea000 000000010000003d 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask
0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE),
pid 6509, tgid 6509 (syz-executor.3), ts 50269499850, free_ts
50269456139
 prep_new_page+0x2c6/0x350
 get_page_from_freelist+0xae9/0x3a80
 __alloc_pages+0x321/0x710
 cache_grow_begin+0x75/0x360
 kmem_cache_alloc_node_trace+0xbe2/0xd40
 __kmalloc_node+0x38/0x60
 __vmalloc_node_range+0x3d3/0x1320
 vzalloc+0x67/0x80
 alloc_counters.isra.0+0x5d/0x6f0
 do_ipt_get_ctl+0x5de/0x980
 nf_getsockopt+0x72/0xd0
 ip_getsockopt+0x164/0x1c0
 tcp_getsockopt+0x86/0xd0
 __sys_getsockopt+0x216/0x690
 __x64_sys_getsockopt+0xba/0x150
 do_syscall_64+0x35/0xb0
page last free stack trace:
 free_pcp_prepare+0x5ab/0xd00
 free_unref_page+0x19/0x410
 __vunmap+0x6ff/0xaa0
 __vfree+0x3c/0xd0
 vfree+0x5a/0x90
 do_ipt_get_ctl+0x7b2/0x980
 nf_getsockopt+0x72/0xd0
 ip_getsockopt+0x164/0x1c0
 tcp_getsockopt+0x86/0xd0
 __sys_getsockopt+0x216/0x690
 __x64_sys_getsockopt+0xba/0x150
 do_syscall_64+0x35/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888104fea500: fa fb fb fb fc fc fc fc 02 fc fc fc fc fc fc fc
 ffff888104fea580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff888104fea600: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                                           ^
 ffff888104fea680: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff888104fea700: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================