syzbot

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BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xa98/0xaf8 net/dns_resolver/dns_key.c:127
Read of size 1 at addr ffff0000c9641c04 by task syz-executor388/3965

CPU: 1 PID: 3965 Comm: syz-executor388 Not tainted 5.15.146-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 __asan_report_load1_noabort+0x44/0x50 mm/kasan/report_generic.c:306
 dns_resolver_preparse+0xa98/0xaf8 net/dns_resolver/dns_key.c:127
 key_create_or_update+0x43c/0xa38 security/keys/key.c:861
 __do_sys_add_key security/keys/keyctl.c:134 [inline]
 __se_sys_add_key security/keys/keyctl.c:74 [inline]
 __arm64_sys_add_key+0x440/0x578 security/keys/keyctl.c:74
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Allocated by task 3965:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc_node+0x2c0/0x5b8 mm/slub.c:4455
 kmalloc_node include/linux/slab.h:614 [inline]
 kvmalloc_node+0x88/0x204 mm/util.c:619
 kvmalloc include/linux/mm.h:805 [inline]
 __do_sys_add_key security/keys/keyctl.c:116 [inline]
 __se_sys_add_key security/keys/keyctl.c:74 [inline]
 __arm64_sys_add_key+0x29c/0x578 security/keys/keyctl.c:74
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the object at ffff0000c9641c00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 4 bytes inside of
 128-byte region [ffff0000c9641c00, ffff0000c9641c80)
The buggy address belongs to the page:
page:00000000b441518f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109641
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 fffffc0003269700 0000000200000002 ffff0000c0002300
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000c9641b00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000c9641b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000c9641c00: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff0000c9641c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000c9641d00: 05 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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