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BUG: KASAN: slab-out-of-bounds in cap_convert_nscap+0x501/0x610 security/commoncap.c:498
Read of size 4 at addr ffff8801d813a1c0 by task syz-executor0/23807

CPU: 0 PID: 23807 Comm: syz-executor0 Not tainted 4.15.0-rc5+ #243
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_convert_nscap+0x501/0x610 security/commoncap.c:498
 setxattr+0x365/0x400 fs/xattr.c:446
 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
RIP: 0033:0x452ac9
RSP: 002b:00007fd28bb15c58 EFLAGS: 00000212 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007fd28bb16700 RCX: 0000000000452ac9
RDX: 0000000020f4affd RSI: 000000002022cfec RDI: 0000000020712ff8
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a2f7ef R14: 00007fd28bb169c0 R15: 0000000000000000

Allocated by task 23807:
 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_node mm/slab.c:3672 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3679
 kmalloc_node include/linux/slab.h:541 [inline]
 kvmalloc_node+0x99/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:541 [inline]
 setxattr+0x152/0x400 fs/xattr.c:435
 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

Freed by task 20834:
 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:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 selinux_sk_free_security+0x4f/0x60 security/selinux/hooks.c:4908
 security_sk_free+0x48/0x80 security/security.c:1431
 sk_prot_free net/core/sock.c:1502 [inline]
 __sk_destruct+0x609/0x910 net/core/sock.c:1585
 sk_destruct+0x47/0x80 net/core/sock.c:1593
 __sk_free+0x57/0x230 net/core/sock.c:1601
 sk_free+0x2a/0x40 net/core/sock.c:1612
 sock_put include/net/sock.h:1656 [inline]
 tcp_close+0x847/0xfc0 net/ipv4/tcp.c:2319
 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:426
 sock_release+0x8d/0x1e0 net/socket.c:600
 sock_close+0x16/0x20 net/socket.c:1129
 __fput+0x327/0x7e0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9bb/0x1ad0 kernel/exit.c:865
 do_group_exit+0x149/0x400 kernel/exit.c:968
 get_signal+0x73f/0x16c0 kernel/signal.c:2335
 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x94/0x96

The buggy address belongs to the object at ffff8801d813a1c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801d813a1c0, ffff8801d813a1e0)
The buggy address belongs to the page:
page:000000002b734d57 count:1 mapcount:0 mapping:000000000ef205a0 index:0xffff8801d813afc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d813a000 ffff8801d813afc1 000000010000003f
raw: ffffea0007596ca0 ffffea00075ea8a0 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d813a080: fb fb fb fb fc fc fc fc 05 fc fc fc fc fc fc fc
 ffff8801d813a100: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d813a180: fb fb fb fb fc fc fc fc 03 fc fc fc fc fc fc fc
                                           ^
 ffff8801d813a200: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d813a280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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