syzbot

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BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xcaf/0xd20 net/dns_resolver/dns_key.c:127
Read of size 1 at addr ffff888018f7657c by task syz-executor400/3546

CPU: 0 PID: 3546 Comm: syz-executor400 Not tainted 6.1.70-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 dns_resolver_preparse+0xcaf/0xd20 net/dns_resolver/dns_key.c:127
 key_create_or_update+0x47b/0xbf0 security/keys/key.c:861
 __do_sys_add_key security/keys/keyctl.c:134 [inline]
 __se_sys_add_key+0x33b/0x480 security/keys/keyctl.c:74
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f538c7c1329
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffee89b21a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8
RAX: ffffffffffffffda RBX: 00007ffee89b2378 RCX: 00007f538c7c1329
RDX: 0000000020000080 RSI: 0000000000000000 RDI: 00000000200003c0
RBP: 00007f538c834610 R08: 00000000173ffeb4 R09: 00007ffee89b2378
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffee89b2368 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Allocated by task 3546:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x97/0xb0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:955 [inline]
 __kmalloc_node+0xb3/0x230 mm/slab_common.c:962
 kmalloc_node include/linux/slab.h:579 [inline]
 kvmalloc_node+0x6e/0x180 mm/util.c:581
 kvmalloc include/linux/slab.h:706 [inline]
 __do_sys_add_key security/keys/keyctl.c:116 [inline]
 __se_sys_add_key+0x26c/0x480 security/keys/keyctl.c:74
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888018f76578
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 4 bytes inside of
 8-byte region [ffff888018f76578, ffff888018f76580)

The buggy address belongs to the physical page:
page:ffffea000063dd80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x18f76
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00008fba80 dead000000000002 ffff888012441280
raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 3003, tgid 3003 (udevadm), ts 15293965490, free_ts 12727125892
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513
 prep_new_page mm/page_alloc.c:2520 [inline]
 get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5545
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:954 [inline]
 __kmalloc+0xa1/0x230 mm/slab_common.c:968
 kmalloc include/linux/slab.h:558 [inline]
 kernfs_fop_write_iter+0x157/0x4f0 fs/kernfs/file.c:307
 call_write_iter include/linux/fs.h:2248 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7ae/0xba0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1440 [inline]
 free_pcp_prepare mm/page_alloc.c:1490 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3358
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3453
 kasan_depopulate_vmalloc_pte+0x66/0x80 mm/kasan/shadow.c:375
 apply_to_pte_range mm/memory.c:2645 [inline]
 apply_to_pmd_range mm/memory.c:2689 [inline]
 apply_to_pud_range mm/memory.c:2725 [inline]
 apply_to_p4d_range mm/memory.c:2761 [inline]
 __apply_to_page_range+0x9c5/0xcc0 mm/memory.c:2795
 kasan_release_vmalloc+0x96/0xb0 mm/kasan/shadow.c:492
 __purge_vmap_area_lazy+0x157c/0x1720 mm/vmalloc.c:1774
 _vm_unmap_aliases+0x476/0x4e0 mm/vmalloc.c:2177
 change_page_attr_set_clr+0x308/0x1050 arch/x86/mm/pat/set_memory.c:1781
 change_page_attr_set arch/x86/mm/pat/set_memory.c:1831 [inline]
 set_memory_nx+0xee/0x130 arch/x86/mm/pat/set_memory.c:2024
 free_init_pages arch/x86/mm/init.c:937 [inline]
 free_kernel_image_pages arch/x86/mm/init.c:956 [inline]
 free_initmem+0x71/0xc0 arch/x86/mm/init.c:983
 kernel_init+0x2d/0x290 init/main.c:1521
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Memory state around the buggy address:
 ffff888018f76400: fc fc fa fc fc fc fc fa fc fc fc fc 00 fc fc fc
 ffff888018f76480: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc
>ffff888018f76500: fa fc fc fc fc fa fc fc fc fc 05 fc fc fc fc 04
                                                                ^
 ffff888018f76580: fc fc fc fc fb fc fc fc fc fb fc fc fc fc 00 fc
 ffff888018f76600: fc fc fc 00 fc fc fc fc fb fc fc fc fc fb fc fc
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