audit: type=1400 audit(1601796150.287:8): avc:  denied  { execmem } for  pid=6369 comm="syz-executor978" 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 ffff88809fa928a0 by task syz-executor978/6369

CPU: 0 PID: 6369 Comm: syz-executor978 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:00007fff04f65f38 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff04f65f90 RCX: 0000000000446d2a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff04f65f50
RBP: 00007fff04f65f50 R08: 00007fff04f65f90 R09: 00007fff00000015
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 6369:
 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+0x15a/0x400 mm/slab.c:3729
 kmalloc_array include/linux/slab.h:607 [inline]
 kcalloc include/linux/slab.h:618 [inline]
 squashfs_read_data+0x153/0x1140 fs/squashfs/block.c:100
 squashfs_read_table+0x11c/0x18d fs/squashfs/cache.c:445
 squashfs_read_id_index_table+0x6f/0xc0 fs/squashfs/id.c:90
 squashfs_fill_super+0xd7a/0x1640 fs/squashfs/super.c:246
 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

Freed by task 6369:
 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
 squashfs_read_data+0x931/0x1140 fs/squashfs/block.c:205
 squashfs_read_table+0x11c/0x18d fs/squashfs/cache.c:445
 squashfs_read_id_index_table+0x6f/0xc0 fs/squashfs/id.c:90
 squashfs_fill_super+0xd7a/0x1640 fs/squashfs/super.c:246
 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

The buggy address belongs to the object at ffff88809fa92880
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 32-byte region [ffff88809fa92880, ffff88809fa928a0)
The buggy address belongs to the page:
page:ffffea00027ea480 count:1 mapcount:0 mapping:ffff88809fa92000 index:0xffff88809fa92fc1
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809fa92000 ffff88809fa92fc1 000000010000003d
raw: ffffea00027d6360 ffffea00027d1ce0 ffff88812fe501c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809fa92780: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
 ffff88809fa92800: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
>ffff88809fa92880: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                               ^
 ffff88809fa92900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809fa92980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================