audit: type=1400 audit(1601513215.566:8): avc:  denied  { execmem } for  pid=6467 comm="syz-executor188" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
==================================================================
BUG: KASAN: slab-out-of-bounds in squashfs_get_id+0x1bc/0x1f0 fs/squashfs/id.c:51
Read of size 8 at addr ffff8880a4650938 by task syz-executor188/6467

CPU: 0 PID: 6467 Comm: syz-executor188 Not tainted 4.19.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x22c/0x33e lib/dump_stack.c:118
 print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
 kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 squashfs_get_id+0x1bc/0x1f0 fs/squashfs/id.c:51
 squashfs_new_inode fs/squashfs/inode.c:68 [inline]
 squashfs_read_inode+0x1d3/0x1940 fs/squashfs/inode.c:133
 squashfs_fill_super+0x1277/0x190a fs/squashfs/super.c:318
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x318 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x51c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446d2a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffcf85de1a8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffcf85de200 RCX: 0000000000446d2a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffcf85de1c0
RBP: 00007ffcf85de1c0 R08: 00007ffcf85de200 R09: 00007ffc00000015
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 4689:
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc_track_caller+0x155/0x4e0 mm/slab.c:3742
 kmemdup_nul+0x2d/0xa0 mm/util.c:138
 security_context_to_sid_core+0xb2/0x610 security/selinux/ss/services.c:1463
 security_context_to_sid+0x35/0x40 security/selinux/ss/services.c:1525
 selinux_inode_setsecurity+0x197/0x3d0 security/selinux/hooks.c:3501
 selinux_inode_notifysecctx+0x2b/0x60 security/selinux/hooks.c:6667
 security_inode_notifysecctx+0x50/0xb0 security/security.c:1343
 kernfs_refresh_inode+0x328/0x4b0 fs/kernfs/inode.c:195
 kernfs_iop_permission+0x6a/0xb0 fs/kernfs/inode.c:302
 do_inode_permission fs/namei.c:386 [inline]
 inode_permission+0x34e/0x540 fs/namei.c:451
 may_lookup fs/namei.c:1703 [inline]
 link_path_walk.part.0+0x952/0x1230 fs/namei.c:2085
 link_path_walk fs/namei.c:2270 [inline]
 path_lookupat+0xe4/0x8d0 fs/namei.c:2318
 filename_lookup+0x1ac/0x5a0 fs/namei.c:2349
 user_path_at include/linux/namei.h:57 [inline]
 do_faccessat+0x262/0x7f0 fs/open.c:397
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4689:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x250 mm/slab.c:3822
 security_context_to_sid_core+0x2ed/0x610 security/selinux/ss/services.c:1504
 security_context_to_sid+0x35/0x40 security/selinux/ss/services.c:1525
 selinux_inode_setsecurity+0x197/0x3d0 security/selinux/hooks.c:3501
 selinux_inode_notifysecctx+0x2b/0x60 security/selinux/hooks.c:6667
 security_inode_notifysecctx+0x50/0xb0 security/security.c:1343
 kernfs_refresh_inode+0x328/0x4b0 fs/kernfs/inode.c:195
 kernfs_iop_permission+0x6a/0xb0 fs/kernfs/inode.c:302
 do_inode_permission fs/namei.c:386 [inline]
 inode_permission+0x34e/0x540 fs/namei.c:451
 may_lookup fs/namei.c:1703 [inline]
 link_path_walk.part.0+0x952/0x1230 fs/namei.c:2085
 link_path_walk fs/namei.c:2270 [inline]
 path_lookupat+0xe4/0x8d0 fs/namei.c:2318
 filename_lookup+0x1ac/0x5a0 fs/namei.c:2349
 user_path_at include/linux/namei.h:57 [inline]
 do_faccessat+0x262/0x7f0 fs/open.c:397
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a4650900
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes to the right of
 32-byte region [ffff8880a4650900, ffff8880a4650920)
The buggy address belongs to the page:
page:ffffea0002919400 count:1 mapcount:0 mapping:ffff88812c3f61c0 index:0xffff8880a4650fc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea0002918c88 ffffea0002a06bc8 ffff88812c3f61c0
raw: ffff8880a4650fc1 ffff8880a4650000 0000000100000039 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a4650800: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
 ffff8880a4650880: 00 00 01 fc fc fc fc fc 00 03 fc fc fc fc fc fc
>ffff8880a4650900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                                        ^
 ffff8880a4650980: 00 03 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a4650a00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================