KASAN: slab-out-of-bounds Write in hdr_insert_head

Status: moderation: reported on 2026/05/19 16:21
Subsystems: ntfs3
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+45ef5a8d661162757547@syzkaller.appspotmail.com
First crash: 69d, last: 69d
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ID Workflow Result Correct Bug Created Started Finished Revision Error
bf511a52-e93d-43c6-8b0e-6cf21c1f988a assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-out-of-bounds Write in hdr_insert_head 2026/06/01 14:13 2026/06/01 14:13 2026/06/01 14:42 386cc6dacdf7e3ebce9507beed6755d7e999554d 

			
				
	

	
	



			

		

	

	
	

		

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			[PATCH] ntfs3: bound index head insertions by buffer capacity
			1 (1)
			2026/06/28 09:55
		

	
	




			
			
		

	

	

	
	
Sample crash report:

	
loop0: detected capacity change from 0 to 4096
ntfs3(loop0): Different NTFS sector size (4096) and media sector size (512).
ntfs3(loop0): Failed to initialize $Extend/$Reparse.
==================================================================
BUG: KASAN: slab-out-of-bounds in hdr_insert_head+0x122/0x1d0 fs/ntfs3/index.c:600
Write of size 16 at addr ffff888040609938 by task syz.0.0/5324

CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 __asan_memmove+0x40/0x70 mm/kasan/shadow.c:95
 hdr_insert_head+0x122/0x1d0 fs/ntfs3/index.c:600
 indx_insert_into_root+0x14fd/0x1e00 fs/ntfs3/index.c:1746
 indx_insert_entry+0x649/0x8a0 fs/ntfs3/index.c:2002
 ntfs_create_inode+0x23f5/0x34b0 fs/ntfs3/inode.c:1664
 ntfs_create+0x3d/0x50 fs/ntfs3/namei.c:110
 lookup_open fs/namei.c:4511 [inline]
 open_last_lookups fs/namei.c:4611 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_creat fs/open.c:1448 [inline]
 __se_sys_creat fs/open.c:1442 [inline]
 __x64_sys_creat+0x8f/0xc0 fs/open.c:1442
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd8a139ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd8a2319fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fd8a1615fa0 RCX: 00007fd8a139ce59
RDX: 0000000000000000 RSI: 0000000000000185 RDI: 0000200000000e00
RBP: 00007fd8a1432d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd8a1616038 R14: 00007fd8a1615fa0 R15: 00007ffe4a12be58
 </TASK>

Allocated by task 5287:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_node_track_caller_noprof+0x4db/0x7b0 mm/slub.c:5407
 kmemdup_noprof+0x2b/0x70 mm/util.c:138
 kmemdup_noprof include/linux/fortify-string.h:763 [inline]
 ipt_nat_register_lookups net/ipv4/netfilter/iptable_nat.c:71 [inline]
 iptable_nat_table_init+0x9d/0x300 net/ipv4/netfilter/iptable_nat.c:121
 xt_find_table_lock+0x30c/0x3f0 net/netfilter/x_tables.c:1353
 xt_request_find_table_lock+0x26/0x100 net/netfilter/x_tables.c:1378
 get_info net/ipv4/netfilter/ip_tables.c:963 [inline]
 do_ipt_get_ctl+0x716/0x1240 net/ipv4/netfilter/ip_tables.c:1659
 nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
 ip_getsockopt+0x19e/0x230 net/ipv4/ip_sockglue.c:1777
 do_sock_getsockopt+0x569/0xa70 net/socket.c:2487
 __sys_getsockopt net/socket.c:2518 [inline]
 __do_sys_getsockopt net/socket.c:2525 [inline]
 __se_sys_getsockopt net/socket.c:2522 [inline]
 __x64_sys_getsockopt+0x1a4/0x240 net/socket.c:2522
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888040609800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes to the right of
 allocated 288-byte region [ffff888040609800, ffff888040609920)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40608
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801ac41c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff88801ac41c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 04fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5282, tgid 5282 (mkswap), ts 73055197477, free_ts 62741925076
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7255
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __do_kmalloc_node mm/slub.c:5294 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5307
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_init_log+0x1aae/0x1fb0 security/tomoyo/audit.c:273
 tomoyo_supervisor+0x353/0x1570 security/tomoyo/common.c:2232
 tomoyo_audit_path_log security/tomoyo/file.c:169 [inline]
 tomoyo_path_permission+0x25a/0x380 security/tomoyo/file.c:592
 tomoyo_check_open_permission+0x2b2/0x470 security/tomoyo/file.c:782
 security_file_open+0xa9/0x240 security/security.c:2739
 do_dentry_open+0x384/0x14e0 fs/open.c:924
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4699 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4858
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
page last free pid 5239 tgid 5239 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
 __slab_free+0x274/0x2c0 mm/slub.c:5612
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 __kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5414
 kmalloc_noprof include/linux/slab.h:950 [inline]
 tomoyo_print_header security/tomoyo/audit.c:156 [inline]
 tomoyo_init_log+0x195/0x1fb0 security/tomoyo/audit.c:253
 tomoyo_supervisor+0x353/0x1570 security/tomoyo/common.c:2232
 tomoyo_audit_path_log security/tomoyo/file.c:169 [inline]
 tomoyo_path_permission+0x25a/0x380 security/tomoyo/file.c:592
 tomoyo_check_open_permission+0x2b2/0x470 security/tomoyo/file.c:782
 security_file_open+0xa9/0x240 security/security.c:2739
 do_dentry_open+0x384/0x14e0 fs/open.c:924
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4699 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4858
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364

Memory state around the buggy address:
 ffff888040609800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888040609880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888040609900: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
                                        ^
 ffff888040609980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888040609a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================



	

	



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			2026/05/15 16:16
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			KASAN: slab-out-of-bounds Write in hdr_insert_head
		

		
		


* Struck through repros no longer work on HEAD.