audit: type=1400 audit(1514746920.328:7): avc:  denied  { map } for  pid=3155 comm="syzkaller937981" path="/root/syzkaller937981273" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
==================================================================
BUG: KASAN: slab-out-of-bounds in cap_inode_getsecurity+0x621/0x7d0 security/commoncap.c:408
Read of size 4 at addr ffff8801c8d0cc40 by task syzkaller937981/3155

CPU: 0 PID: 3155 Comm: syzkaller937981 Not tainted 4.15.0-rc4-next-20171221+ #78
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 cap_inode_getsecurity+0x621/0x7d0 security/commoncap.c:408
 security_inode_getsecurity+0xcd/0x110 security/security.c:809
 xattr_getsecurity+0xd3/0x1f0 fs/xattr.c:244
 vfs_getxattr+0xc8/0x110 fs/xattr.c:333
 getxattr+0x116/0x2a0 fs/xattr.c:540
 path_getxattr+0xed/0x170 fs/xattr.c:568
 SYSC_getxattr fs/xattr.c:580 [inline]
 SyS_getxattr+0x33/0x40 fs/xattr.c:577
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x43fd09
RSP: 002b:00007ffee6309898 EFLAGS: 00000217 ORIG_RAX: 00000000000000bf
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 000000000043fd09
RDX: 0000000020227f74 RSI: 0000000020b29f57 RDI: 000000002072d000
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000008c R11: 0000000000000217 R12: 0000000000401670
R13: 0000000000401700 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 3155:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3709 [inline]
 __kmalloc_track_caller+0x15e/0x760 mm/slab.c:3724
 __do_krealloc mm/slab_common.c:1449 [inline]
 krealloc+0x65/0xc0 mm/slab_common.c:1496
 vfs_getxattr_alloc+0x177/0x270 fs/xattr.c:290
 cap_inode_getsecurity+0xfa/0x7d0 security/commoncap.c:399
 security_inode_getsecurity+0xcd/0x110 security/security.c:809
 xattr_getsecurity+0xd3/0x1f0 fs/xattr.c:244
 vfs_getxattr+0xc8/0x110 fs/xattr.c:333
 getxattr+0x116/0x2a0 fs/xattr.c:540
 path_getxattr+0xed/0x170 fs/xattr.c:568
 SYSC_getxattr fs/xattr.c:580 [inline]
 SyS_getxattr+0x33/0x40 fs/xattr.c:577
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 1693:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3489 [inline]
 kfree+0xd6/0x260 mm/slab.c:3804
 security_context_to_sid_core+0x182/0x5a0 security/selinux/ss/services.c:1460
 security_context_to_sid+0x32/0x40 security/selinux/ss/services.c:1480
 selinux_inode_setxattr+0x3a2/0xa60 security/selinux/hooks.c:3192
 security_inode_setxattr+0xf3/0x170 security/security.c:731
 vfs_setxattr+0xa0/0xe0 fs/xattr.c:220
 setxattr+0x319/0x400 fs/xattr.c:453
 path_setxattr+0x198/0x1e0 fs/xattr.c:472
 SYSC_lsetxattr fs/xattr.c:494 [inline]
 SyS_lsetxattr+0x38/0x50 fs/xattr.c:490
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801c8d0cc40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801c8d0cc40, ffff8801c8d0cc60)
The buggy address belongs to the page:
page:00000000fc227142 count:1 mapcount:0 mapping:00000000434ec1ae index:0xffff8801c8d0cfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c8d0c000 ffff8801c8d0cfc1 000000010000003f
raw: ffffea0007264720 ffffea000726d620 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c8d0cb00: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801c8d0cb80: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801c8d0cc00: 00 00 01 fc fc fc fc fc 01 fc fc fc fc fc fc fc
                                           ^
 ffff8801c8d0cc80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801c8d0cd00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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