================================================================== BUG: KASAN: slab-out-of-bounds in vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3275 Read of size 1 at addr ffff8880a8ea6403 by task syz-executor.1/11383 CPU: 0 PID: 11383 Comm: syz-executor.1 Not tainted 5.6.0-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+0x1e9/0x30e lib/dump_stack.c:118 print_address_description+0x74/0x5c0 mm/kasan/report.c:374 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:506 kasan_report+0x25/0x50 mm/kasan/common.c:641 vsscanf+0x2666/0x2ef0 lib/vsprintf.c:3275 sscanf+0x6c/0x90 lib/vsprintf.c:3481 smk_set_cipso+0x1ac/0x6a0 security/smack/smackfs.c:881 __vfs_write+0xa7/0x710 fs/read_write.c:494 vfs_write+0x274/0x570 fs/read_write.c:558 ksys_write+0x11b/0x220 fs/read_write.c:611 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c849 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8199a1bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f8199a1c6d4 RCX: 000000000045c849 RDX: 0000000000000002 RSI: 00000000200002c0 RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000cfa R14: 00000000004cf202 R15: 000000000076bf0c Allocated by task 11383: save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc_track_caller+0x249/0x320 mm/slab.c:3671 memdup_user_nul+0x26/0xf0 mm/util.c:259 smk_set_cipso+0xff/0x6a0 security/smack/smackfs.c:859 __vfs_write+0xa7/0x710 fs/read_write.c:494 vfs_write+0x274/0x570 fs/read_write.c:558 ksys_write+0x11b/0x220 fs/read_write.c:611 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 11117: save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x220 mm/slab.c:3757 smk_import_entry+0x40f/0x560 security/smack/smack_access.c:578 smk_fetch security/smack/smack_lsm.c:300 [inline] smack_d_instantiate+0x6e1/0xd90 security/smack/smack_lsm.c:3408 security_d_instantiate+0xa5/0x100 security/security.c:1925 d_instantiate_new+0x61/0x110 fs/dcache.c:1973 ext4_add_nondir+0x1f6/0x260 fs/ext4/namei.c:2582 ext4_symlink+0x8ba/0xef0 fs/ext4/namei.c:3364 vfs_symlink+0x36f/0x500 fs/namei.c:4201 do_symlinkat+0x18b/0x420 fs/namei.c:4228 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff8880a8ea6400 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 3 bytes inside of 32-byte region [ffff8880a8ea6400, ffff8880a8ea6420) The buggy address belongs to the page: page:ffffea0002a3a980 refcount:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff8880a8ea6fc1 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002a47148 ffffea00029d9dc8 ffff8880aa4001c0 raw: ffff8880a8ea6fc1 ffff8880a8ea6000 000000010000003f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a8ea6300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ffff8880a8ea6380: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc >ffff8880a8ea6400: 03 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc ^ ffff8880a8ea6480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ffff8880a8ea6500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ==================================================================