Subject: [syzbot] [net?] KASAN: use-after-free Read in rhashtable_lookup_fast (2)

From: syzbot <[email-masked]>
Date: Mon, 03 Jun 2024 09:20:22 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    3e9bc0472b91 Merge branch 'bpf: Add BPF_PROG_TYPE_CGROUP_S..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1209e85c980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=98d5a8e00ed1044a
dashboard link: https://syzkaller.appspot.com/bug?extid=128aaac913636290e5a9
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b4d98ec9bb7b/disk-3e9bc047.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/df7961b4e331/vmlinux-3e9bc047.xz
kernel image: https://storage.googleapis.com/syzbot-assets/be4e509c6f1b/bzImage-3e9bc047.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline]
BUG: KASAN: use-after-free in __rhashtable_lookup include/linux/rhashtable.h:604 [inline]
BUG: KASAN: use-after-free in rhashtable_lookup include/linux/rhashtable.h:646 [inline]
BUG: KASAN: use-after-free in rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672
Read of size 4 at addr ffff888058fe8008 by task kworker/1:9/5947

CPU: 1 PID: 5947 Comm: kworker/1:9 Not tainted 6.9.0-rc5-syzkaller-00185-g3e9bc0472b91 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: wg-crypt-wg1 wg_packet_encrypt_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 rht_key_hashfn include/linux/rhashtable.h:159 [inline]
 __rhashtable_lookup include/linux/rhashtable.h:604 [inline]
 rhashtable_lookup include/linux/rhashtable.h:646 [inline]
 rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672
 ila_lookup_wildcards net/ipv6/ila/ila_xlat.c:132 [inline]
 ila_xlat_addr net/ipv6/ila/ila_xlat.c:652 [inline]
 ila_nf_input+0x1fe/0x3c0 net/ipv6/ila/ila_xlat.c:190
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312
 __netif_receive_skb_one_core net/core/dev.c:5544 [inline]
 __netif_receive_skb+0x1ea/0x650 net/core/dev.c:5658
 process_backlog+0x39d/0x7a0 net/core/dev.c:5987
 __napi_poll+0xcb/0x490 net/core/dev.c:6638
 napi_poll net/core/dev.c:6707 [inline]
 net_rx_action+0x7bb/0x1090 net/core/dev.c:6822
 __do_softirq+0x2c6/0x980 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_encrypt_worker+0x2e8/0x1610 drivers/net/wireguard/send.c:293
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x58fe8
flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x152dc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_ZERO), pid 11308, tgid -1154580940 (syz-executor.4), ts 11308, free_ts 301906279236
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 __kmalloc_large_node+0x91/0x1f0 mm/slub.c:3911
 __do_kmalloc_node mm/slub.c:3954 [inline]
 __kmalloc_node+0x33e/0x4e0 mm/slub.c:3973
 kmalloc_node include/linux/slab.h:648 [inline]
 kvmalloc_node+0x72/0x190 mm/util.c:634
 kvmalloc include/linux/slab.h:766 [inline]
 kvzalloc include/linux/slab.h:774 [inline]
 bucket_table_alloc lib/rhashtable.c:184 [inline]
 rhashtable_init+0x558/0xa90 lib/rhashtable.c:1065
 ila_xlat_init_net+0xa0/0x110 net/ipv6/ila/ila_xlat.c:613
 ops_init+0x352/0x610 net/core/net_namespace.c:136
 setup_net+0x515/0xca0 net/core/net_namespace.c:340
 copy_net_ns+0x4e4/0x7b0 net/core/net_namespace.c:505
 create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
 ksys_unshare+0x619/0xc10 kernel/fork.c:3323
 __do_sys_unshare kernel/fork.c:3394 [inline]
 __se_sys_unshare kernel/fork.c:3392 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3392
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
page last free pid 1100 tgid 1100 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x986/0xab0 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 __folio_put_large+0x13f/0x190 mm/swap.c:132
 __folio_put+0x299/0x390 mm/swap.c:140
 folio_put include/linux/mm.h:1506 [inline]
 free_large_kmalloc+0x105/0x1c0 mm/slub.c:4361
 kfree+0x1ca/0x3a0 mm/slub.c:4384
 rhashtable_free_and_destroy+0x7c6/0x920 lib/rhashtable.c:1163
 ila_xlat_exit_net+0x55/0x110 net/ipv6/ila/ila_xlat.c:626
 ops_exit_list net/core/net_namespace.c:170 [inline]
 cleanup_net+0x802/0xcc0 net/core/net_namespace.c:637
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff888058fe7f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888058fe7f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888058fe8000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff888058fe8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888058fe8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

---
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