audit: type=1400 audit(1601384703.135:8): avc:  denied  { execmem } for  pid=6363 comm="syz-executor906" 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+0x181/0x1a0 fs/squashfs/id.c:51
Read of size 8 at addr ffff8880a42149e0 by task syz-executor906/6363

CPU: 0 PID: 6363 Comm: syz-executor906 Not tainted 4.14.198-syzkaller #0
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+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 squashfs_get_id+0x181/0x1a0 fs/squashfs/id.c:51
 squashfs_new_inode fs/squashfs/inode.c:64 [inline]
 squashfs_read_inode+0x171/0x1840 fs/squashfs/inode.c:133
 squashfs_fill_super+0x1138/0x1640 fs/squashfs/super.c:318
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x446d2a
RSP: 002b:00007ffe83cc92b8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe83cc9310 RCX: 0000000000446d2a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffe83cc92d0
RBP: 00007ffe83cc92d0 R08: 00007ffe83cc9310 R09: 00007ffe00000015
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 4674:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc_track_caller+0x155/0x400 mm/slab.c:3735
 kmemdup_nul+0x2d/0xa0 mm/util.c:138
 security_context_to_sid_core+0x94/0x3d0 security/selinux/ss/services.c:1420
 selinux_inode_setsecurity+0x155/0x350 security/selinux/hooks.c:3377
 selinux_inode_notifysecctx+0x2b/0x50 security/selinux/hooks.c:6152
 security_inode_notifysecctx+0x76/0xb0 security/security.c:1314
 kernfs_refresh_inode+0x328/0x4a0 fs/kernfs/inode.c:195
 kernfs_iop_permission+0x59/0x90 fs/kernfs/inode.c:302
 do_inode_permission fs/namei.c:384 [inline]
 __inode_permission+0x1f1/0x2f0 fs/namei.c:426
 inode_permission fs/namei.c:476 [inline]
 may_lookup fs/namei.c:1717 [inline]
 link_path_walk+0x86a/0x10a0 fs/namei.c:2097
 path_lookupat+0xcb/0x780 fs/namei.c:2342
 filename_lookup+0x18a/0x510 fs/namei.c:2377
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0xd1/0x180 fs/stat.c:185
 vfs_lstat include/linux/fs.h:3070 [inline]
 SYSC_newlstat fs/stat.c:350 [inline]
 SyS_newlstat+0x83/0xe0 fs/stat.c:344
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 4674:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 security_context_to_sid_core+0x28a/0x3d0 security/selinux/ss/services.c:1460
 selinux_inode_setsecurity+0x155/0x350 security/selinux/hooks.c:3377
 selinux_inode_notifysecctx+0x2b/0x50 security/selinux/hooks.c:6152
 security_inode_notifysecctx+0x76/0xb0 security/security.c:1314
 kernfs_refresh_inode+0x328/0x4a0 fs/kernfs/inode.c:195
 kernfs_iop_permission+0x59/0x90 fs/kernfs/inode.c:302
 do_inode_permission fs/namei.c:384 [inline]
 __inode_permission+0x1f1/0x2f0 fs/namei.c:426
 inode_permission fs/namei.c:476 [inline]
 may_lookup fs/namei.c:1717 [inline]
 link_path_walk+0x86a/0x10a0 fs/namei.c:2097
 path_lookupat+0xcb/0x780 fs/namei.c:2342
 filename_lookup+0x18a/0x510 fs/namei.c:2377
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0xd1/0x180 fs/stat.c:185
 vfs_lstat include/linux/fs.h:3070 [inline]
 SYSC_newlstat fs/stat.c:350 [inline]
 SyS_newlstat+0x83/0xe0 fs/stat.c:344
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880a42149c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 32-byte region [ffff8880a42149c0, ffff8880a42149e0)
The buggy address belongs to the page:
page:ffffea0002908500 count:1 mapcount:0 mapping:ffff8880a4214000 index:0xffff8880a4214fc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880a4214000 ffff8880a4214fc1 0000000100000010
raw: ffffea0002905a20 ffffea0002902660 ffff88812fe501c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a4214880: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a4214900: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
>ffff8880a4214980: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                                                       ^
 ffff8880a4214a00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a4214a80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================