KASAN: slab-out-of-bounds Read in ip6_route_output

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KMSAN: kernel-infoleak in copyout (2) net	C			6723	664d	1832d	22/28	fixed on 2023/06/08 14:41
Created	Duration	User	Patch	Repo	Result
2025/02/26 19:08	22m	retest repro		upstream	report log
==================================================================
BUG: KASAN: slab-out-of-bounds in inet6_sk include/linux/ipv6.h:322 [inline]
BUG: KASAN: slab-out-of-bounds in ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
BUG: KASAN: slab-out-of-bounds in ip6_route_output_flags+0x336/0x610 net/ipv6/route.c:2651
Read of size 8 at addr ffff88803cbc17d0 by task kworker/u4:8/1040

CPU: 0 UID: 0 PID: 1040 Comm: kworker/u4:8 Not tainted 6.14.0-rc2-syzkaller-00039-g09fbf3d50205 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 inet6_sk include/linux/ipv6.h:322 [inline]
 ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
 ip6_route_output_flags+0x336/0x610 net/ipv6/route.c:2651
 ip6_route_output include/net/ip6_route.h:93 [inline]
 ip6_dst_lookup_tail+0x1b3/0x14f0 net/ipv6/ip6_output.c:1128
 ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1259
 udp_tunnel6_dst_lookup+0x2be/0x520 net/ipv6/ip6_udp_tunnel.c:165
 geneve6_xmit_skb drivers/net/geneve.c:950 [inline]
 geneve_xmit+0xcf2/0x2cf0 drivers/net/geneve.c:1036
 __netdev_start_xmit include/linux/netdevice.h:5144 [inline]
 netdev_start_xmit include/linux/netdevice.h:5153 [inline]
 xmit_one net/core/dev.c:3735 [inline]
 dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3751
 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4584
 dev_queue_xmit include/linux/netdevice.h:3305 [inline]
 neigh_hh_output include/net/neighbour.h:523 [inline]
 neigh_output include/net/neighbour.h:537 [inline]
 ip6_finish_output2+0x1263/0x1780 net/ipv6/ip6_output.c:141
 ip6_finish_output+0x41e/0x840 net/ipv6/ip6_output.c:226
 NF_HOOK+0x9e/0x430 include/linux/netfilter.h:314
 mld_sendpack+0x843/0xdb0 net/ipv6/mcast.c:1862
 ipv6_mc_dad_complete+0x88/0x490 net/ipv6/mcast.c:2288
 addrconf_dad_completed+0x712/0xcd0 net/ipv6/addrconf.c:4336
 addrconf_dad_work+0xdbc/0x16a0
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Last potentially related work creation:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 early_kmem_cache_node_alloc mm/slub.c:5338 [inline]
 init_kmem_cache_nodes mm/slub.c:5380 [inline]
 do_kmem_cache_create+0x294/0x6b0 mm/slub.c:6207
 create_boot_cache+0xbb/0x130 mm/slab_common.c:678
 kmem_cache_init+0x95/0x180 mm/slub.c:6080
 mm_core_init+0x33/0x60 mm/mm_init.c:2660
 start_kernel+0x1a1/0x510 init/main.c:957
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515
 x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:496
 common_startup_64+0x13e/0x147

Second to last potentially related work creation:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4216
 alloc_unbound_pwq+0xaeb/0x1070 kernel/workqueue.c:5165
 apply_wqattrs_prepare+0x481/0xef0 kernel/workqueue.c:5286
 apply_workqueue_attrs_locked+0x63/0x200 kernel/workqueue.c:5362
 alloc_and_link_pwqs kernel/workqueue.c:5519 [inline]
 __alloc_workqueue+0x1285/0x1f20 kernel/workqueue.c:5734
 alloc_workqueue+0xd6/0x210 kernel/workqueue.c:5784
 workqueue_init_early+0xadd/0xd60 kernel/workqueue.c:7819
 start_kernel+0x1f7/0x510 init/main.c:988
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515
 x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:496
 common_startup_64+0x13e/0x147

The buggy address belongs to the object at ffff88803cbc1200
 which belongs to the cache sock_inode_cache of size 1408
The buggy address is located 80 bytes to the right of
 allocated 1408-byte region [ffff88803cbc1200, ffff88803cbc1780)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803cbc0c00 pfn:0x3cbc0
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888040c04c81
flags: 0x4fff00000000240(workingset|head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000240 ffff888030ec1dc0 ffffea000109c910 ffffea00010ad610
raw: ffff88803cbc0c00 00000000000a0002 00000000f5000000 ffff888040c04c81
head: 04fff00000000240 ffff888030ec1dc0 ffffea000109c910 ffffea00010ad610
head: ffff88803cbc0c00 00000000000a0002 00000000f5000000 ffff888040c04c81
head: 04fff00000000002 ffffea0000f2f001 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_RECLAIMABLE), pid 5344, tgid 5344 (syz-executor), ts 89780557259, free_ts 89769440350
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_lru_noprof+0x26c/0x390 mm/slub.c:4183
 sock_alloc_inode+0x28/0xc0 net/socket.c:309
 alloc_inode+0x65/0x1a0 fs/inode.c:336
 sock_alloc net/socket.c:622 [inline]
 __sock_create+0x127/0xa30 net/socket.c:1512
 sock_create net/socket.c:1606 [inline]
 __sys_socket_create net/socket.c:1643 [inline]
 __sys_socket+0x150/0x3c0 net/socket.c:1690
 __do_sys_socket net/socket.c:1704 [inline]
 __se_sys_socket net/socket.c:1702 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1702
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5344 tgid 5344 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 __slab_free+0x2c2/0x380 mm/slub.c:4520
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 __kmalloc_cache_noprof+0x1d9/0x390 mm/slub.c:4320
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 find_css_set+0xb07/0x1720 kernel/cgroup/cgroup.c:1194
 cgroup_migrate_prepare_dst+0x124/0x690 kernel/cgroup/cgroup.c:2804
 cgroup_attach_task+0x697/0xaf0 kernel/cgroup/cgroup.c:2908
 __cgroup1_procs_write+0x2e3/0x430 kernel/cgroup/cgroup-v1.c:528
 cgroup_file_write+0x2ce/0x6d0 kernel/cgroup/cgroup.c:4142
 kernfs_fop_write_iter+0x3a0/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xacf/0xd10 fs/read_write.c:679
 ksys_write+0x18f/0x2b0 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88803cbc1680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88803cbc1700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88803cbc1780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                 ^
 ffff88803cbc1800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803cbc1880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================