linux.git/net/ipv6, branch v6.1

ipv6: avoid use-after-free in ip6_fragment()

2022-12-08T04:14:35+00:00

Blamed commit claimed rcu_read_lock() was held by ip6_fragment() callers.

It seems to not be always true, at least for UDP stack.

syzbot reported:

BUG: KASAN: use-after-free in ip6_dst_idev include/net/ip6_fib.h:245 [inline]
BUG: KASAN: use-after-free in ip6_fragment+0x2724/0x2770 net/ipv6/ip6_output.c:951
Read of size 8 at addr ffff88801d403e80 by task syz-executor.3/7618

CPU: 1 PID: 7618 Comm: syz-executor.3 Not tainted 6.1.0-rc6-syzkaller-00012-g4312098baf37 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:395
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:495
 ip6_dst_idev include/net/ip6_fib.h:245 [inline]
 ip6_fragment+0x2724/0x2770 net/ipv6/ip6_output.c:951
 __ip6_finish_output net/ipv6/ip6_output.c:193 [inline]
 ip6_finish_output+0x9a3/0x1170 net/ipv6/ip6_output.c:206
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x1f1/0x540 net/ipv6/ip6_output.c:227
 dst_output include/net/dst.h:445 [inline]
 ip6_local_out+0xb3/0x1a0 net/ipv6/output_core.c:161
 ip6_send_skb+0xbb/0x340 net/ipv6/ip6_output.c:1966
 udp_v6_send_skb+0x82a/0x18a0 net/ipv6/udp.c:1286
 udp_v6_push_pending_frames+0x140/0x200 net/ipv6/udp.c:1313
 udpv6_sendmsg+0x18da/0x2c80 net/ipv6/udp.c:1606
 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:665
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xd3/0x120 net/socket.c:734
 sock_write_iter+0x295/0x3d0 net/socket.c:1108
 call_write_iter include/linux/fs.h:2191 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x9ed/0xdd0 fs/read_write.c:584
 ksys_write+0x1ec/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fde3588c0d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007fde365b6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fde359ac050 RCX: 00007fde3588c0d9
RDX: 000000000000ffdc RSI: 00000000200000c0 RDI: 000000000000000a
RBP: 00007fde358e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fde35acfb1f R14: 00007fde365b6300 R15: 0000000000022000
 

Allocated by task 7618:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 __kasan_slab_alloc+0x82/0x90 mm/kasan/common.c:325
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x2b4/0x3d0 mm/slub.c:3422
 dst_alloc+0x14a/0x1f0 net/core/dst.c:92
 ip6_dst_alloc+0x32/0xa0 net/ipv6/route.c:344
 ip6_rt_pcpu_alloc net/ipv6/route.c:1369 [inline]
 rt6_make_pcpu_route net/ipv6/route.c:1417 [inline]
 ip6_pol_route+0x901/0x1190 net/ipv6/route.c:2254
 pol_lookup_func include/net/ip6_fib.h:582 [inline]
 fib6_rule_lookup+0x52e/0x6f0 net/ipv6/fib6_rules.c:121
 ip6_route_output_flags_noref+0x2e6/0x380 net/ipv6/route.c:2625
 ip6_route_output_flags+0x76/0x320 net/ipv6/route.c:2638
 ip6_route_output include/net/ip6_route.h:98 [inline]
 ip6_dst_lookup_tail+0x5ab/0x1620 net/ipv6/ip6_output.c:1092
 ip6_dst_lookup_flow+0x90/0x1d0 net/ipv6/ip6_output.c:1222
 ip6_sk_dst_lookup_flow+0x553/0x980 net/ipv6/ip6_output.c:1260
 udpv6_sendmsg+0x151d/0x2c80 net/ipv6/udp.c:1554
 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:665
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xd3/0x120 net/socket.c:734
 __sys_sendto+0x23a/0x340 net/socket.c:2117
 __do_sys_sendto net/socket.c:2129 [inline]
 __se_sys_sendto net/socket.c:2125 [inline]
 __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2125
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 7599:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:511
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1750
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free+0xee/0x5c0 mm/slub.c:3683
 dst_destroy+0x2ea/0x400 net/core/dst.c:127
 rcu_do_batch kernel/rcu/tree.c:2250 [inline]
 rcu_core+0x81f/0x1980 kernel/rcu/tree.c:2510
 __do_softirq+0x1fb/0xadc kernel/softirq.c:571

Last potentially related work creation:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
 call_rcu+0x9d/0x820 kernel/rcu/tree.c:2798
 dst_release net/core/dst.c:177 [inline]
 dst_release+0x7d/0xe0 net/core/dst.c:167
 refdst_drop include/net/dst.h:256 [inline]
 skb_dst_drop include/net/dst.h:268 [inline]
 skb_release_head_state+0x250/0x2a0 net/core/skbuff.c:838
 skb_release_all net/core/skbuff.c:852 [inline]
 __kfree_skb net/core/skbuff.c:868 [inline]
 kfree_skb_reason+0x151/0x4b0 net/core/skbuff.c:891
 kfree_skb_list_reason+0x4b/0x70 net/core/skbuff.c:901
 kfree_skb_list include/linux/skbuff.h:1227 [inline]
 ip6_fragment+0x2026/0x2770 net/ipv6/ip6_output.c:949
 __ip6_finish_output net/ipv6/ip6_output.c:193 [inline]
 ip6_finish_output+0x9a3/0x1170 net/ipv6/ip6_output.c:206
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x1f1/0x540 net/ipv6/ip6_output.c:227
 dst_output include/net/dst.h:445 [inline]
 ip6_local_out+0xb3/0x1a0 net/ipv6/output_core.c:161
 ip6_send_skb+0xbb/0x340 net/ipv6/ip6_output.c:1966
 udp_v6_send_skb+0x82a/0x18a0 net/ipv6/udp.c:1286
 udp_v6_push_pending_frames+0x140/0x200 net/ipv6/udp.c:1313
 udpv6_sendmsg+0x18da/0x2c80 net/ipv6/udp.c:1606
 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:665
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xd3/0x120 net/socket.c:734
 sock_write_iter+0x295/0x3d0 net/socket.c:1108
 call_write_iter include/linux/fs.h:2191 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x9ed/0xdd0 fs/read_write.c:584
 ksys_write+0x1ec/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
 call_rcu+0x9d/0x820 kernel/rcu/tree.c:2798
 dst_release net/core/dst.c:177 [inline]
 dst_release+0x7d/0xe0 net/core/dst.c:167
 refdst_drop include/net/dst.h:256 [inline]
 skb_dst_drop include/net/dst.h:268 [inline]
 __dev_queue_xmit+0x1b9d/0x3ba0 net/core/dev.c:4211
 dev_queue_xmit include/linux/netdevice.h:3008 [inline]
 neigh_resolve_output net/core/neighbour.c:1552 [inline]
 neigh_resolve_output+0x51b/0x840 net/core/neighbour.c:1532
 neigh_output include/net/neighbour.h:546 [inline]
 ip6_finish_output2+0x56c/0x1530 net/ipv6/ip6_output.c:134
 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline]
 ip6_finish_output+0x694/0x1170 net/ipv6/ip6_output.c:206
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x1f1/0x540 net/ipv6/ip6_output.c:227
 dst_output include/net/dst.h:445 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 NF_HOOK include/linux/netfilter.h:296 [inline]
 mld_sendpack+0xa09/0xe70 net/ipv6/mcast.c:1820
 mld_send_cr net/ipv6/mcast.c:2121 [inline]
 mld_ifc_work+0x720/0xdc0 net/ipv6/mcast.c:2653
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff88801d403dc0
 which belongs to the cache ip6_dst_cache of size 240
The buggy address is located 192 bytes inside of
 240-byte region [ffff88801d403dc0, ffff88801d403eb0)

The buggy address belongs to the physical page:
page:ffffea00007500c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d403
memcg:ffff888022f49c81
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0001ef6580 dead000000000002 ffff88814addf640
raw: 0000000000000000 00000000800c000c 00000001ffffffff ffff888022f49c81
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 3719, tgid 3719 (kworker/0:6), ts 136223432244, free_ts 136222971441
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4288
 __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5555
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
 alloc_slab_page mm/slub.c:1794 [inline]
 allocate_slab+0x213/0x300 mm/slub.c:1939
 new_slab mm/slub.c:1992 [inline]
 ___slab_alloc+0xa91/0x1400 mm/slub.c:3180
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3279
 slab_alloc_node mm/slub.c:3364 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x31a/0x3d0 mm/slub.c:3422
 dst_alloc+0x14a/0x1f0 net/core/dst.c:92
 ip6_dst_alloc+0x32/0xa0 net/ipv6/route.c:344
 icmp6_dst_alloc+0x71/0x680 net/ipv6/route.c:3261
 mld_sendpack+0x5de/0xe70 net/ipv6/mcast.c:1809
 mld_send_cr net/ipv6/mcast.c:2121 [inline]
 mld_ifc_work+0x720/0xdc0 net/ipv6/mcast.c:2653
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1509
 free_unref_page_prepare mm/page_alloc.c:3387 [inline]
 free_unref_page+0x1d/0x4d0 mm/page_alloc.c:3483
 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2586
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x184/0x210 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x66/0x90 mm/kasan/common.c:302
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3398 [inline]
 kmem_cache_alloc_node+0x304/0x410 mm/slub.c:3443
 __alloc_skb+0x214/0x300 net/core/skbuff.c:497
 alloc_skb include/linux/skbuff.h:1267 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1191 [inline]
 netlink_sendmsg+0x9a6/0xe10 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xd3/0x120 net/socket.c:734
 __sys_sendto+0x23a/0x340 net/socket.c:2117
 __do_sys_sendto net/socket.c:2129 [inline]
 __se_sys_sendto net/socket.c:2125 [inline]
 __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2125
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 1758fd4688eb ("ipv6: remove unnecessary dst_hold() in ip6_fragment()")
Reported-by: syzbot+8c0ac31aa9681abb9e2d@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet 
Cc: Wei Wang 
Cc: Martin KaFai Lau 
Link: https://lore.kernel.org/r/20221206101351.2037285-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

2022-11-24T03:18:59+00:00

Steffen Klassert says:

====================
ipsec 2022-11-23

1) Fix "disable_policy" on ipv4 early demuxP Packets after
   the initial packet in a flow might be incorectly dropped
   on early demux if there are no matching policies.
   From Eyal Birger.

2) Fix a kernel warning in case XFRM encap type is not
   available. From Eyal Birger.

3) Fix ESN wrap around for GSO to avoid a double usage of a
    sequence number. From Christian Langrock.

4) Fix a send_acquire race with pfkey_register.
   From Herbert Xu.

5) Fix a list corruption panic in __xfrm_state_delete().
   Thomas Jarosch.

6) Fix an unchecked return value in xfrm6_init().
   Chen Zhongjin.

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
  xfrm: Fix ignored return value in xfrm6_init()
  xfrm: Fix oops in __xfrm_state_delete()
  af_key: Fix send_acquire race with pfkey_register
  xfrm: replay: Fix ESN wrap around for GSO
  xfrm: lwtunnel: squelch kernel warning in case XFRM encap type is not available
  xfrm: fix "disable_policy" on ipv4 early demux
====================

Link: https://lore.kernel.org/r/20221123093117.434274-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski

dccp/tcp: Fixup bhash2 bucket when connect() fails.

2022-11-23T04:15:37+00:00

If a socket bound to a wildcard address fails to connect(), we
only reset saddr and keep the port.  Then, we have to fix up the
bhash2 bucket; otherwise, the bucket has an inconsistent address
in the list.

Also, listen() for such a socket will fire the WARN_ON() in
inet_csk_get_port(). [0]

Note that when a system runs out of memory, we give up fixing the
bucket and unlink sk from bhash and bhash2 by inet_put_port().

[0]:
WARNING: CPU: 0 PID: 207 at net/ipv4/inet_connection_sock.c:548 inet_csk_get_port (net/ipv4/inet_connection_sock.c:548 (discriminator 1))
Modules linked in:
CPU: 0 PID: 207 Comm: bhash2_prev_rep Not tainted 6.1.0-rc3-00799-gc8421681c845 #63
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014
RIP: 0010:inet_csk_get_port (net/ipv4/inet_connection_sock.c:548 (discriminator 1))
Code: 74 a7 eb 93 48 8b 54 24 18 0f b7 cb 4c 89 e6 4c 89 ff e8 48 b2 ff ff 49 8b 87 18 04 00 00 e9 32 ff ff ff 0f 0b e9 34 ff ff ff <0f> 0b e9 42 ff ff ff 41 8b 7f 50 41 8b 4f 54 89 fe 81 f6 00 00 ff
RSP: 0018:ffffc900003d7e50 EFLAGS: 00010202
RAX: ffff8881047fb500 RBX: 0000000000004e20 RCX: 0000000000000000
RDX: 000000000000000a RSI: 00000000fffffe00 RDI: 00000000ffffffff
RBP: ffffffff8324dc00 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000004e20 R15: ffff8881054e1280
FS:  00007f8ac04dc740(0000) GS:ffff88842fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001540 CR3: 00000001055fa003 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 
 inet_csk_listen_start (net/ipv4/inet_connection_sock.c:1205)
 inet_listen (net/ipv4/af_inet.c:228)
 __sys_listen (net/socket.c:1810)
 __x64_sys_listen (net/socket.c:1819 net/socket.c:1817 net/socket.c:1817)
 do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7f8ac051de5d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d 93 af 1b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc1c177248 EFLAGS: 00000206 ORIG_RAX: 0000000000000032
RAX: ffffffffffffffda RBX: 0000000020001550 RCX: 00007f8ac051de5d
RDX: ffffffffffffff80 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007ffc1c177270 R08: 0000000000000018 R09: 0000000000000007
R10: 0000000020001540 R11: 0000000000000206 R12: 00007ffc1c177388
R13: 0000000000401169 R14: 0000000000403e18 R15: 00007f8ac0723000
 

Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address")
Reported-by: syzbot 
Reported-by: Mat Martineau 
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Joanne Koong 
Reviewed-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski

dccp/tcp: Update saddr under bhash's lock.

2022-11-23T04:15:36+00:00

When we call connect() for a socket bound to a wildcard address, we update
saddr locklessly.  However, it could result in a data race; another thread
iterating over bhash might see a corrupted address.

Let's update saddr under the bhash bucket's lock.

Fixes: 3df80d9320bc ("[DCCP]: Introduce DCCPv6")
Fixes: 7c657876b63c ("[DCCP]: Initial implementation")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Joanne Koong 
Reviewed-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski

dccp/tcp: Reset saddr on failure after inet6?_hash_connect().

2022-11-23T04:15:36+00:00

When connect() is called on a socket bound to the wildcard address,
we change the socket's saddr to a local address.  If the socket
fails to connect() to the destination, we have to reset the saddr.

However, when an error occurs after inet_hash6?_connect() in
(dccp|tcp)_v[46]_conect(), we forget to reset saddr and leave
the socket bound to the address.

From the user's point of view, whether saddr is reset or not varies
with errno.  Let's fix this inconsistent behaviour.

Note that after this patch, the repro [0] will trigger the WARN_ON()
in inet_csk_get_port() again, but this patch is not buggy and rather
fixes a bug papering over the bhash2's bug for which we need another
fix.

For the record, the repro causes -EADDRNOTAVAIL in inet_hash6_connect()
by this sequence:

  s1 = socket()
  s1.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
  s1.bind(('127.0.0.1', 10000))
  s1.sendto(b'hello', MSG_FASTOPEN, (('127.0.0.1', 10000)))
  # or s1.connect(('127.0.0.1', 10000))

  s2 = socket()
  s2.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
  s2.bind(('0.0.0.0', 10000))
  s2.connect(('127.0.0.1', 10000))  # -EADDRNOTAVAIL

  s2.listen(32)  # WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2);

[0]: https://syzkaller.appspot.com/bug?extid=015d756bbd1f8b5c8f09

Fixes: 3df80d9320bc ("[DCCP]: Introduce DCCPv6")
Fixes: 7c657876b63c ("[DCCP]: Initial implementation")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Joanne Koong 
Reviewed-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski

xfrm: Fix ignored return value in xfrm6_init()

2022-11-22T06:16:34+00:00

When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
is possible to fail but its return value is ignored.

If IPv6 initialization fails later and xfrm6_fini() is called,
removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:

KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 330 Comm: insmod
RIP: 0010:unregister_pernet_operations+0xc9/0x450
Call Trace:
 
 unregister_pernet_subsys+0x31/0x3e
 xfrm6_fini+0x16/0x30 [ipv6]
 ip6_route_init+0xcd/0x128 [ipv6]
 inet6_init+0x29c/0x602 [ipv6]
 ...

Fix it by catching the error return value of register_pernet_subsys().

Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
Signed-off-by: Chen Zhongjin 
Reviewed-by: Leon Romanovsky 
Signed-off-by: Steffen Klassert

ipv6: addrlabel: fix infoleak when sending struct ifaddrlblmsg to network

2022-11-07T12:26:15+00:00

When copying a `struct ifaddrlblmsg` to the network, __ifal_reserved
remained uninitialized, resulting in a 1-byte infoleak:

  BUG: KMSAN: kernel-network-infoleak in __netdev_start_xmit ./include/linux/netdevice.h:4841
   __netdev_start_xmit ./include/linux/netdevice.h:4841
   netdev_start_xmit ./include/linux/netdevice.h:4857
   xmit_one net/core/dev.c:3590
   dev_hard_start_xmit+0x1dc/0x800 net/core/dev.c:3606
   __dev_queue_xmit+0x17e8/0x4350 net/core/dev.c:4256
   dev_queue_xmit ./include/linux/netdevice.h:3009
   __netlink_deliver_tap_skb net/netlink/af_netlink.c:307
   __netlink_deliver_tap+0x728/0xad0 net/netlink/af_netlink.c:325
   netlink_deliver_tap net/netlink/af_netlink.c:338
   __netlink_sendskb net/netlink/af_netlink.c:1263
   netlink_sendskb+0x1d9/0x200 net/netlink/af_netlink.c:1272
   netlink_unicast+0x56d/0xf50 net/netlink/af_netlink.c:1360
   nlmsg_unicast ./include/net/netlink.h:1061
   rtnl_unicast+0x5a/0x80 net/core/rtnetlink.c:758
   ip6addrlbl_get+0xfad/0x10f0 net/ipv6/addrlabel.c:628
   rtnetlink_rcv_msg+0xb33/0x1570 net/core/rtnetlink.c:6082
  ...
  Uninit was created at:
   slab_post_alloc_hook+0x118/0xb00 mm/slab.h:742
   slab_alloc_node mm/slub.c:3398
   __kmem_cache_alloc_node+0x4f2/0x930 mm/slub.c:3437
   __do_kmalloc_node mm/slab_common.c:954
   __kmalloc_node_track_caller+0x117/0x3d0 mm/slab_common.c:975
   kmalloc_reserve net/core/skbuff.c:437
   __alloc_skb+0x27a/0xab0 net/core/skbuff.c:509
   alloc_skb ./include/linux/skbuff.h:1267
   nlmsg_new ./include/net/netlink.h:964
   ip6addrlbl_get+0x490/0x10f0 net/ipv6/addrlabel.c:608
   rtnetlink_rcv_msg+0xb33/0x1570 net/core/rtnetlink.c:6082
   netlink_rcv_skb+0x299/0x550 net/netlink/af_netlink.c:2540
   rtnetlink_rcv+0x26/0x30 net/core/rtnetlink.c:6109
   netlink_unicast_kernel net/netlink/af_netlink.c:1319
   netlink_unicast+0x9ab/0xf50 net/netlink/af_netlink.c:1345
   netlink_sendmsg+0xebc/0x10f0 net/netlink/af_netlink.c:1921
  ...

This patch ensures that the reserved field is always initialized.

Reported-by: syzbot+3553517af6020c4f2813f1003fe76ef3cbffe98d@syzkaller.appspotmail.com
Fixes: 2a8cc6c89039 ("[IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.")
Signed-off-by: Alexander Potapenko 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: fix WARNING in ip6_route_net_exit_late()

2022-11-03T03:47:14+00:00

During the initialization of ip6_route_net_init_late(), if file
ipv6_route or rt6_stats fails to be created, the initialization is
successful by default. Therefore, the ipv6_route or rt6_stats file
doesn't be found during the remove in ip6_route_net_exit_late(). It
will cause WRNING.

The following is the stack information:
name 'rt6_stats'
WARNING: CPU: 0 PID: 9 at fs/proc/generic.c:712 remove_proc_entry+0x389/0x460
Modules linked in:
Workqueue: netns cleanup_net
RIP: 0010:remove_proc_entry+0x389/0x460
PKRU: 55555554
Call Trace:

ops_exit_list+0xb0/0x170
cleanup_net+0x4ea/0xb00
process_one_work+0x9bf/0x1710
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30


Fixes: cdb1876192db ("[NETNS][IPV6] route6 - create route6 proc files for the namespace")
Signed-off-by: Zhengchao Shao 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20221102020610.351330-1-shaozhengchao@huawei.com
Signed-off-by: Jakub Kicinski

udp: advertise ipv6 udp support for msghdr::ubuf_info

2022-10-29T03:21:25+00:00

Mark udp ipv6 as supporting msghdr::ubuf_info. In the original commit
SOCK_SUPPORT_ZC was supposed to be set by a udp_init_sock() call from
udp6_init_sock(), but
d38afeec26ed4 ("tcp/udp: Call inet6_destroy_sock() in IPv6 ...")
removed it and so ipv6 udp misses the flag.

Cc:  # 6.0
Fixes: e993ffe3da4bc ("net: flag sockets supporting msghdr originated zerocopy")
Signed-off-by: Pavel Begunkov 
Signed-off-by: Jakub Kicinski

ipv6: ensure sane device mtu in tunnels

2022-10-25T23:04:22+00:00

Another syzbot report [1] with no reproducer hints
at a bug in ip6_gre tunnel (dev:ip6gretap0)

Since ipv6 mcast code makes sure to read dev->mtu once
and applies a sanity check on it (see commit b9b312a7a451
"ipv6: mcast: better catch silly mtu values"), a remaining
possibility is that a layer is able to set dev->mtu to
an underflowed value (high order bit set).

This could happen indeed in ip6gre_tnl_link_config_route(),
ip6_tnl_link_config() and ipip6_tunnel_bind_dev()

Make sure to sanitize mtu value in a local variable before
it is written once on dev->mtu, as lockless readers could
catch wrong temporary value.

[1]
skbuff: skb_over_panic: text:ffff80000b7a2f38 len:40 put:40 head:ffff000149dcf200 data:ffff000149dcf2b0 tail:0xd8 end:0xc0 dev:ip6gretap0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:120
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 10241 Comm: kworker/1:1 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Workqueue: mld mld_ifc_work
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : skb_panic+0x4c/0x50 net/core/skbuff.c:116
lr : skb_panic+0x4c/0x50 net/core/skbuff.c:116
sp : ffff800020dd3b60
x29: ffff800020dd3b70 x28: 0000000000000000 x27: ffff00010df2a800
x26: 00000000000000c0 x25: 00000000000000b0 x24: ffff000149dcf200
x23: 00000000000000c0 x22: 00000000000000d8 x21: ffff80000b7a2f38
x20: ffff00014c2f7800 x19: 0000000000000028 x18: 00000000000001a9
x17: 0000000000000000 x16: ffff80000db49158 x15: ffff000113bf1a80
x14: 0000000000000000 x13: 00000000ffffffff x12: ffff000113bf1a80
x11: ff808000081c0d5c x10: 0000000000000000 x9 : 73f125dc5c63ba00
x8 : 73f125dc5c63ba00 x7 : ffff800008161d1c x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : ffff0001fefddcd0 x1 : 0000000100000000 x0 : 0000000000000089
Call trace:
skb_panic+0x4c/0x50 net/core/skbuff.c:116
skb_over_panic net/core/skbuff.c:125 [inline]
skb_put+0xd4/0xdc net/core/skbuff.c:2049
ip6_mc_hdr net/ipv6/mcast.c:1714 [inline]
mld_newpack+0x14c/0x270 net/ipv6/mcast.c:1765
add_grhead net/ipv6/mcast.c:1851 [inline]
add_grec+0xa20/0xae0 net/ipv6/mcast.c:1989
mld_send_cr+0x438/0x5a8 net/ipv6/mcast.c:2115
mld_ifc_work+0x38/0x290 net/ipv6/mcast.c:2653
process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
worker_thread+0x340/0x610 kernel/workqueue.c:2436
kthread+0x12c/0x158 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860
Code: 91011400 aa0803e1 a90027ea 94373093 (d4210000)

Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20221024020124.3756833-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski