linux-stable.git/net/ipv6, branch v6.8.4 Linux kernel stable tree net: esp: fix bad handling of pages from page_pool 2024-04-03T13:32:24+00:00 Dragos Tatulea dtatulea@nvidia.com 2024-03-08T15:26:00+00:00 f278ff9db67264715d0d50e3e75044f8b78990f4 [ Upstream commit c3198822c6cb9fb588e446540485669cc81c5d34 ] When the skb is reorganized during esp_output (!esp->inline), the pages coming from the original skb fragments are supposed to be released back to the system through put_page. But if the skb fragment pages are originating from a page_pool, calling put_page on them will trigger a page_pool leak which will eventually result in a crash. This leak can be easily observed when using CONFIG_DEBUG_VM and doing ipsec + gre (non offloaded) forwarding: BUG: Bad page state in process ksoftirqd/16 pfn:1451b6 page:00000000de2b8d32 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1451b6000 pfn:0x1451b6 flags: 0x200000000000000(node=0|zone=2) page_type: 0xffffffff() raw: 0200000000000000 dead000000000040 ffff88810d23c000 0000000000000000 raw: 00000001451b6000 0000000000000001 00000000ffffffff 0000000000000000 page dumped because: page_pool leak Modules linked in: ip_gre gre mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core overlay zram zsmalloc fuse [last unloaded: mlx5_core] CPU: 16 PID: 96 Comm: ksoftirqd/16 Not tainted 6.8.0-rc4+ #22 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x36/0x50 bad_page+0x70/0xf0 free_unref_page_prepare+0x27a/0x460 free_unref_page+0x38/0x120 esp_ssg_unref.isra.0+0x15f/0x200 esp_output_tail+0x66d/0x780 esp_xmit+0x2c5/0x360 validate_xmit_xfrm+0x313/0x370 ? validate_xmit_skb+0x1d/0x330 validate_xmit_skb_list+0x4c/0x70 sch_direct_xmit+0x23e/0x350 __dev_queue_xmit+0x337/0xba0 ? nf_hook_slow+0x3f/0xd0 ip_finish_output2+0x25e/0x580 iptunnel_xmit+0x19b/0x240 ip_tunnel_xmit+0x5fb/0xb60 ipgre_xmit+0x14d/0x280 [ip_gre] dev_hard_start_xmit+0xc3/0x1c0 __dev_queue_xmit+0x208/0xba0 ? nf_hook_slow+0x3f/0xd0 ip_finish_output2+0x1ca/0x580 ip_sublist_rcv_finish+0x32/0x40 ip_sublist_rcv+0x1b2/0x1f0 ? ip_rcv_finish_core.constprop.0+0x460/0x460 ip_list_rcv+0x103/0x130 __netif_receive_skb_list_core+0x181/0x1e0 netif_receive_skb_list_internal+0x1b3/0x2c0 napi_gro_receive+0xc8/0x200 gro_cell_poll+0x52/0x90 __napi_poll+0x25/0x1a0 net_rx_action+0x28e/0x300 __do_softirq+0xc3/0x276 ? sort_range+0x20/0x20 run_ksoftirqd+0x1e/0x30 smpboot_thread_fn+0xa6/0x130 kthread+0xcd/0x100 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x31/0x50 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork_asm+0x11/0x20 </TASK> The suggested fix is to introduce a new wrapper (skb_page_unref) that covers page refcounting for page_pool pages as well. Cc: stable@vger.kernel.org Fixes: 6a5bcd84e886 ("page_pool: Allow drivers to hint on SKB recycling") Reported-and-tested-by: Anatoli N.Chechelnickiy <Anatoli.Chechelnickiy@m.interpipe.biz> Reported-by: Ian Kumlien <ian.kumlien@gmail.com> Link: https://lore.kernel.org/netdev/CAA85sZvvHtrpTQRqdaOx6gd55zPAVsqMYk_Lwh4Md5knTq7AyA@mail.gmail.com Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c3198822c6cb9fb588e446540485669cc81c5d34 ]

When the skb is reorganized during esp_output (!esp->inline), the pages
coming from the original skb fragments are supposed to be released back
to the system through put_page. But if the skb fragment pages are
originating from a page_pool, calling put_page on them will trigger a
page_pool leak which will eventually result in a crash.

This leak can be easily observed when using CONFIG_DEBUG_VM and doing
ipsec + gre (non offloaded) forwarding:

  BUG: Bad page state in process ksoftirqd/16  pfn:1451b6
  page:00000000de2b8d32 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1451b6000 pfn:0x1451b6
  flags: 0x200000000000000(node=0|zone=2)
  page_type: 0xffffffff()
  raw: 0200000000000000 dead000000000040 ffff88810d23c000 0000000000000000
  raw: 00000001451b6000 0000000000000001 00000000ffffffff 0000000000000000
  page dumped because: page_pool leak
  Modules linked in: ip_gre gre mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core overlay zram zsmalloc fuse [last unloaded: mlx5_core]
  CPU: 16 PID: 96 Comm: ksoftirqd/16 Not tainted 6.8.0-rc4+ #22
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x36/0x50
   bad_page+0x70/0xf0
   free_unref_page_prepare+0x27a/0x460
   free_unref_page+0x38/0x120
   esp_ssg_unref.isra.0+0x15f/0x200
   esp_output_tail+0x66d/0x780
   esp_xmit+0x2c5/0x360
   validate_xmit_xfrm+0x313/0x370
   ? validate_xmit_skb+0x1d/0x330
   validate_xmit_skb_list+0x4c/0x70
   sch_direct_xmit+0x23e/0x350
   __dev_queue_xmit+0x337/0xba0
   ? nf_hook_slow+0x3f/0xd0
   ip_finish_output2+0x25e/0x580
   iptunnel_xmit+0x19b/0x240
   ip_tunnel_xmit+0x5fb/0xb60
   ipgre_xmit+0x14d/0x280 [ip_gre]
   dev_hard_start_xmit+0xc3/0x1c0
   __dev_queue_xmit+0x208/0xba0
   ? nf_hook_slow+0x3f/0xd0
   ip_finish_output2+0x1ca/0x580
   ip_sublist_rcv_finish+0x32/0x40
   ip_sublist_rcv+0x1b2/0x1f0
   ? ip_rcv_finish_core.constprop.0+0x460/0x460
   ip_list_rcv+0x103/0x130
   __netif_receive_skb_list_core+0x181/0x1e0
   netif_receive_skb_list_internal+0x1b3/0x2c0
   napi_gro_receive+0xc8/0x200
   gro_cell_poll+0x52/0x90
   __napi_poll+0x25/0x1a0
   net_rx_action+0x28e/0x300
   __do_softirq+0xc3/0x276
   ? sort_range+0x20/0x20
   run_ksoftirqd+0x1e/0x30
   smpboot_thread_fn+0xa6/0x130
   kthread+0xcd/0x100
   ? kthread_complete_and_exit+0x20/0x20
   ret_from_fork+0x31/0x50
   ? kthread_complete_and_exit+0x20/0x20
   ret_from_fork_asm+0x11/0x20
   </TASK>

The suggested fix is to introduce a new wrapper (skb_page_unref) that
covers page refcounting for page_pool pages as well.

Cc: stable@vger.kernel.org
Fixes: 6a5bcd84e886 ("page_pool: Allow drivers to hint on SKB recycling")
Reported-and-tested-by: Anatoli N.Chechelnickiy <Anatoli.Chechelnickiy@m.interpipe.biz>
Reported-by: Ian Kumlien <ian.kumlien@gmail.com>
Link: https://lore.kernel.org/netdev/CAA85sZvvHtrpTQRqdaOx6gd55zPAVsqMYk_Lwh4Md5knTq7AyA@mail.gmail.com
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv6: fib6_rules: flush route cache when rule is changed 2024-03-26T22:16:55+00:00 Shiming Cheng shiming.cheng@mediatek.com 2024-03-07T10:01:57+00:00 d27460be824241af3ff12a08dee33220da8c33c1 [ Upstream commit c4386ab4f6c600f75fdfd21143f89bac3e625d0d ] When rule policy is changed, ipv6 socket cache is not refreshed. The sock's skb still uses a outdated route cache and was sent to a wrong interface. To avoid this error we should update fib node's version when rule is changed. Then skb's route will be reroute checked as route cache version is already different with fib node version. The route cache is refreshed to match the latest rule. Fixes: 101367c2f8c4 ("[IPV6]: Policy Routing Rules") Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com> Signed-off-by: Lena Wang <lena.wang@mediatek.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c4386ab4f6c600f75fdfd21143f89bac3e625d0d ]

When rule policy is changed, ipv6 socket cache is not refreshed.
The sock's skb still uses a outdated route cache and was sent to
a wrong interface.

To avoid this error we should update fib node's version when
rule is changed. Then skb's route will be reroute checked as
route cache version is already different with fib node version.
The route cache is refreshed to match the latest rule.

Fixes: 101367c2f8c4 ("[IPV6]: Policy Routing Rules")
Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
Signed-off-by: Lena Wang <lena.wang@mediatek.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv6: mcast: remove one synchronize_net() barrier in ipv6_mc_down() 2024-03-26T22:16:42+00:00 Eric Dumazet edumazet@google.com 2024-02-09T15:30:56+00:00 5da9a218340a2bc804dc4327e5804392e24a0b88 [ Upstream commit 17ef8efc00b34918b966388b2af0993811895a8c ] As discussed in the past (commit 2d3916f31891 ("ipv6: fix skb drops in igmp6_event_query() and igmp6_event_report()")) I think the synchronize_net() call in ipv6_mc_down() is not needed. Under load, synchronize_net() can last between 200 usec and 5 ms. KASAN seems to agree as well. Fixes: f185de28d9ae ("mld: add new workqueues for process mld events") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Taehee Yoo <ap420073@gmail.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 17ef8efc00b34918b966388b2af0993811895a8c ]

As discussed in the past (commit 2d3916f31891 ("ipv6: fix skb drops
in igmp6_event_query() and igmp6_event_report()")) I think the
synchronize_net() call in ipv6_mc_down() is not needed.

Under load, synchronize_net() can last between 200 usec and 5 ms.

KASAN seems to agree as well.

Fixes: f185de28d9ae ("mld: add new workqueues for process mld events")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/ipv6: avoid possible UAF in ip6_route_mpath_notify() 2024-03-05T19:16:11+00:00 Eric Dumazet edumazet@google.com 2024-03-03T14:48:00+00:00 685f7d531264599b3f167f1e94bbd22f120e5fab syzbot found another use-after-free in ip6_route_mpath_notify() [1] Commit f7225172f25a ("net/ipv6: prevent use after free in ip6_route_mpath_notify") was not able to fix the root cause. We need to defer the fib6_info_release() calls after ip6_route_mpath_notify(), in the cleanup phase. [1] BUG: KASAN: slab-use-after-free in rt6_fill_node+0x1460/0x1ac0 Read of size 4 at addr ffff88809a07fc64 by task syz-executor.2/23037 CPU: 0 PID: 23037 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-01035-gea7f3cfaa588 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x167/0x540 mm/kasan/report.c:488 kasan_report+0x142/0x180 mm/kasan/report.c:601 rt6_fill_node+0x1460/0x1ac0 inet6_rt_notify+0x13b/0x290 net/ipv6/route.c:6184 ip6_route_mpath_notify net/ipv6/route.c:5198 [inline] ip6_route_multipath_add net/ipv6/route.c:5404 [inline] inet6_rtm_newroute+0x1d0f/0x2300 net/ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f73dd87dda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f73de6550c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f73dd9ac050 RCX: 00007f73dd87dda9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 00007f73dd8ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007f73dd9ac050 R15: 00007ffdbdeb7858 </TASK> Allocated by task 23037: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:372 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slub.c:3981 [inline] __kmalloc+0x22e/0x490 mm/slub.c:3994 kmalloc include/linux/slab.h:594 [inline] kzalloc include/linux/slab.h:711 [inline] fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3758 ip6_route_multipath_add net/ipv6/route.c:5298 [inline] inet6_rtm_newroute+0x744/0x2300 net/ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 Freed by task 16: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640 poison_slab_object+0xa6/0xe0 mm/kasan/common.c:241 __kasan_slab_free+0x34/0x70 mm/kasan/common.c:257 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2121 [inline] slab_free mm/slub.c:4299 [inline] kfree+0x14a/0x380 mm/slub.c:4409 rcu_do_batch kernel/rcu/tree.c:2190 [inline] rcu_core+0xd76/0x1810 kernel/rcu/tree.c:2465 __do_softirq+0x2bb/0x942 kernel/softirq.c:553 Last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xae/0x100 mm/kasan/generic.c:586 __call_rcu_common kernel/rcu/tree.c:2715 [inline] call_rcu+0x167/0xa80 kernel/rcu/tree.c:2829 fib6_info_release include/net/ip6_fib.h:341 [inline] ip6_route_multipath_add net/ipv6/route.c:5344 [inline] inet6_rtm_newroute+0x114d/0x2300 net/ipv6/route.c:5517 rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 The buggy address belongs to the object at ffff88809a07fc00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 100 bytes inside of freed 512-byte region [ffff88809a07fc00, ffff88809a07fe00) The buggy address belongs to the physical page: page:ffffea0002681f00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9a07c head:ffffea0002681f00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000840 ffff888014c41c80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 23028, tgid 23027 (syz-executor.4), ts 2340253595219, free_ts 2339107097036 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533 prep_new_page mm/page_alloc.c:1540 [inline] get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311 __alloc_pages+0x255/0x680 mm/page_alloc.c:4567 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] alloc_slab_page+0x5f/0x160 mm/slub.c:2190 allocate_slab mm/slub.c:2354 [inline] new_slab+0x84/0x2f0 mm/slub.c:2407 ___slab_alloc+0xd17/0x13e0 mm/slub.c:3540 __slab_alloc mm/slub.c:3625 [inline] __slab_alloc_node mm/slub.c:3678 [inline] slab_alloc_node mm/slub.c:3850 [inline] __do_kmalloc_node mm/slub.c:3980 [inline] __kmalloc+0x2e0/0x490 mm/slub.c:3994 kmalloc include/linux/slab.h:594 [inline] kzalloc include/linux/slab.h:711 [inline] new_dir fs/proc/proc_sysctl.c:956 [inline] get_subdir fs/proc/proc_sysctl.c:1000 [inline] sysctl_mkdir_p fs/proc/proc_sysctl.c:1295 [inline] __register_sysctl_table+0xb30/0x1440 fs/proc/proc_sysctl.c:1376 neigh_sysctl_register+0x416/0x500 net/core/neighbour.c:3859 devinet_sysctl_register+0xaf/0x1f0 net/ipv4/devinet.c:2644 inetdev_init+0x296/0x4d0 net/ipv4/devinet.c:286 inetdev_event+0x338/0x15c0 net/ipv4/devinet.c:1555 notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:1987 [inline] call_netdevice_notifiers net/core/dev.c:2001 [inline] register_netdevice+0x15b2/0x1a20 net/core/dev.c:10340 br_dev_newlink+0x27/0x100 net/bridge/br_netlink.c:1563 rtnl_newlink_create net/core/rtnetlink.c:3497 [inline] __rtnl_newlink net/core/rtnetlink.c:3717 [inline] rtnl_newlink+0x158f/0x20a0 net/core/rtnetlink.c:3730 page last free pid 11583 tgid 11583 stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1140 [inline] free_unref_page_prepare+0x968/0xa90 mm/page_alloc.c:2346 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486 kasan_depopulate_vmalloc_pte+0x74/0x90 mm/kasan/shadow.c:415 apply_to_pte_range mm/memory.c:2619 [inline] apply_to_pmd_range mm/memory.c:2663 [inline] apply_to_pud_range mm/memory.c:2699 [inline] apply_to_p4d_range mm/memory.c:2735 [inline] __apply_to_page_range+0x8ec/0xe40 mm/memory.c:2769 kasan_release_vmalloc+0x9a/0xb0 mm/kasan/shadow.c:532 __purge_vmap_area_lazy+0x163f/0x1a10 mm/vmalloc.c:1770 drain_vmap_area_work+0x40/0xd0 mm/vmalloc.c:1804 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787 kthread+0x2ef/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 Memory state around the buggy address: ffff88809a07fb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809a07fb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809a07fc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809a07fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809a07fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Fixes: 3b1137fe7482 ("net: ipv6: Change notifications for multipath add to RTA_MULTIPATH") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20240303144801.702646-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
syzbot found another use-after-free in ip6_route_mpath_notify() [1]

Commit f7225172f25a ("net/ipv6: prevent use after free in
ip6_route_mpath_notify") was not able to fix the root cause.

We need to defer the fib6_info_release() calls after
ip6_route_mpath_notify(), in the cleanup phase.

[1]
BUG: KASAN: slab-use-after-free in rt6_fill_node+0x1460/0x1ac0
Read of size 4 at addr ffff88809a07fc64 by task syz-executor.2/23037

CPU: 0 PID: 23037 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-01035-gea7f3cfaa588 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
  print_address_description mm/kasan/report.c:377 [inline]
  print_report+0x167/0x540 mm/kasan/report.c:488
  kasan_report+0x142/0x180 mm/kasan/report.c:601
 rt6_fill_node+0x1460/0x1ac0
  inet6_rt_notify+0x13b/0x290 net/ipv6/route.c:6184
  ip6_route_mpath_notify net/ipv6/route.c:5198 [inline]
  ip6_route_multipath_add net/ipv6/route.c:5404 [inline]
  inet6_rtm_newroute+0x1d0f/0x2300 net/ipv6/route.c:5517
  rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597
  netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543
  netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
  netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367
  netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908
  sock_sendmsg_nosec net/socket.c:730 [inline]
  __sock_sendmsg+0x221/0x270 net/socket.c:745
  ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
  ___sys_sendmsg net/socket.c:2638 [inline]
  __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f73dd87dda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f73de6550c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f73dd9ac050 RCX: 00007f73dd87dda9
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005
RBP: 00007f73dd8ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f73dd9ac050 R15: 00007ffdbdeb7858
 </TASK>

Allocated by task 23037:
  kasan_save_stack mm/kasan/common.c:47 [inline]
  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
  poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
  __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389
  kasan_kmalloc include/linux/kasan.h:211 [inline]
  __do_kmalloc_node mm/slub.c:3981 [inline]
  __kmalloc+0x22e/0x490 mm/slub.c:3994
  kmalloc include/linux/slab.h:594 [inline]
  kzalloc include/linux/slab.h:711 [inline]
  fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155
  ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3758
  ip6_route_multipath_add net/ipv6/route.c:5298 [inline]
  inet6_rtm_newroute+0x744/0x2300 net/ipv6/route.c:5517
  rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597
  netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543
  netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
  netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367
  netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908
  sock_sendmsg_nosec net/socket.c:730 [inline]
  __sock_sendmsg+0x221/0x270 net/socket.c:745
  ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
  ___sys_sendmsg net/socket.c:2638 [inline]
  __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 16:
  kasan_save_stack mm/kasan/common.c:47 [inline]
  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
  kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640
  poison_slab_object+0xa6/0xe0 mm/kasan/common.c:241
  __kasan_slab_free+0x34/0x70 mm/kasan/common.c:257
  kasan_slab_free include/linux/kasan.h:184 [inline]
  slab_free_hook mm/slub.c:2121 [inline]
  slab_free mm/slub.c:4299 [inline]
  kfree+0x14a/0x380 mm/slub.c:4409
  rcu_do_batch kernel/rcu/tree.c:2190 [inline]
  rcu_core+0xd76/0x1810 kernel/rcu/tree.c:2465
  __do_softirq+0x2bb/0x942 kernel/softirq.c:553

Last potentially related work creation:
  kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
  __kasan_record_aux_stack+0xae/0x100 mm/kasan/generic.c:586
  __call_rcu_common kernel/rcu/tree.c:2715 [inline]
  call_rcu+0x167/0xa80 kernel/rcu/tree.c:2829
  fib6_info_release include/net/ip6_fib.h:341 [inline]
  ip6_route_multipath_add net/ipv6/route.c:5344 [inline]
  inet6_rtm_newroute+0x114d/0x2300 net/ipv6/route.c:5517
  rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597
  netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543
  netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
  netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367
  netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908
  sock_sendmsg_nosec net/socket.c:730 [inline]
  __sock_sendmsg+0x221/0x270 net/socket.c:745
  ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
  ___sys_sendmsg net/socket.c:2638 [inline]
  __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

The buggy address belongs to the object at ffff88809a07fc00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 100 bytes inside of
 freed 512-byte region [ffff88809a07fc00, ffff88809a07fe00)

The buggy address belongs to the physical page:
page:ffffea0002681f00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9a07c
head:ffffea0002681f00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888014c41c80 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 23028, tgid 23027 (syz-executor.4), ts 2340253595219, free_ts 2339107097036
  set_page_owner include/linux/page_owner.h:31 [inline]
  post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
  prep_new_page mm/page_alloc.c:1540 [inline]
  get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
  __alloc_pages+0x255/0x680 mm/page_alloc.c:4567
  __alloc_pages_node include/linux/gfp.h:238 [inline]
  alloc_pages_node include/linux/gfp.h:261 [inline]
  alloc_slab_page+0x5f/0x160 mm/slub.c:2190
  allocate_slab mm/slub.c:2354 [inline]
  new_slab+0x84/0x2f0 mm/slub.c:2407
  ___slab_alloc+0xd17/0x13e0 mm/slub.c:3540
  __slab_alloc mm/slub.c:3625 [inline]
  __slab_alloc_node mm/slub.c:3678 [inline]
  slab_alloc_node mm/slub.c:3850 [inline]
  __do_kmalloc_node mm/slub.c:3980 [inline]
  __kmalloc+0x2e0/0x490 mm/slub.c:3994
  kmalloc include/linux/slab.h:594 [inline]
  kzalloc include/linux/slab.h:711 [inline]
  new_dir fs/proc/proc_sysctl.c:956 [inline]
  get_subdir fs/proc/proc_sysctl.c:1000 [inline]
  sysctl_mkdir_p fs/proc/proc_sysctl.c:1295 [inline]
  __register_sysctl_table+0xb30/0x1440 fs/proc/proc_sysctl.c:1376
  neigh_sysctl_register+0x416/0x500 net/core/neighbour.c:3859
  devinet_sysctl_register+0xaf/0x1f0 net/ipv4/devinet.c:2644
  inetdev_init+0x296/0x4d0 net/ipv4/devinet.c:286
  inetdev_event+0x338/0x15c0 net/ipv4/devinet.c:1555
  notifier_call_chain+0x18f/0x3b0 kernel/notifier.c:93
  call_netdevice_notifiers_extack net/core/dev.c:1987 [inline]
  call_netdevice_notifiers net/core/dev.c:2001 [inline]
  register_netdevice+0x15b2/0x1a20 net/core/dev.c:10340
  br_dev_newlink+0x27/0x100 net/bridge/br_netlink.c:1563
  rtnl_newlink_create net/core/rtnetlink.c:3497 [inline]
  __rtnl_newlink net/core/rtnetlink.c:3717 [inline]
  rtnl_newlink+0x158f/0x20a0 net/core/rtnetlink.c:3730
page last free pid 11583 tgid 11583 stack trace:
  reset_page_owner include/linux/page_owner.h:24 [inline]
  free_pages_prepare mm/page_alloc.c:1140 [inline]
  free_unref_page_prepare+0x968/0xa90 mm/page_alloc.c:2346
  free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
  kasan_depopulate_vmalloc_pte+0x74/0x90 mm/kasan/shadow.c:415
  apply_to_pte_range mm/memory.c:2619 [inline]
  apply_to_pmd_range mm/memory.c:2663 [inline]
  apply_to_pud_range mm/memory.c:2699 [inline]
  apply_to_p4d_range mm/memory.c:2735 [inline]
  __apply_to_page_range+0x8ec/0xe40 mm/memory.c:2769
  kasan_release_vmalloc+0x9a/0xb0 mm/kasan/shadow.c:532
  __purge_vmap_area_lazy+0x163f/0x1a10 mm/vmalloc.c:1770
  drain_vmap_area_work+0x40/0xd0 mm/vmalloc.c:1804
  process_one_work kernel/workqueue.c:2633 [inline]
  process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706
  worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
  kthread+0x2ef/0x390 kernel/kthread.c:388
  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242

Memory state around the buggy address:
 ffff88809a07fb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809a07fb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809a07fc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88809a07fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809a07fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 3b1137fe7482 ("net: ipv6: Change notifications for multipath add to RTA_MULTIPATH")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240303144801.702646-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipv6: fix potential "struct net" leak in inet6_rtm_getaddr() 2024-02-26T11:56:23+00:00 Eric Dumazet edumazet@google.com 2024-02-22T12:17:47+00:00 10bfd453da64a057bcfd1a49fb6b271c48653cdb It seems that if userspace provides a correct IFA_TARGET_NETNSID value but no IFA_ADDRESS and IFA_LOCAL attributes, inet6_rtm_getaddr() returns -EINVAL with an elevated "struct net" refcount. Fixes: 6ecf4c37eb3e ("ipv6: enable IFA_TARGET_NETNSID for RTM_GETADDR") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Ahern <dsahern@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
It seems that if userspace provides a correct IFA_TARGET_NETNSID value
but no IFA_ADDRESS and IFA_LOCAL attributes, inet6_rtm_getaddr()
returns -EINVAL with an elevated "struct net" refcount.

Fixes: 6ecf4c37eb3e ("ipv6: enable IFA_TARGET_NETNSID for RTM_GETADDR")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix write to cloned skb in ipv6_hop_ioam() 2024-02-22T08:28:03+00:00 Justin Iurman justin.iurman@uliege.be 2024-02-19T13:52:54+00:00 f198d933c2e4f8f89e0620fbaf1ea7eac384a0eb ioam6_fill_trace_data() writes inside the skb payload without ensuring it's writeable (e.g., not cloned). This function is called both from the input and output path. The output path (ioam6_iptunnel) already does the check. This commit provides a fix for the input path, inside ipv6_hop_ioam(). It also updates ip6_parse_tlv() to refresh the network header pointer ("nh") when returning from ipv6_hop_ioam(). Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace") Reported-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Justin Iurman <justin.iurman@uliege.be> Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
ioam6_fill_trace_data() writes inside the skb payload without ensuring
it's writeable (e.g., not cloned). This function is called both from the
input and output path. The output path (ioam6_iptunnel) already does the
check. This commit provides a fix for the input path, inside
ipv6_hop_ioam(). It also updates ip6_parse_tlv() to refresh the network
header pointer ("nh") when returning from ipv6_hop_ioam().

Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace")
Reported-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
ipv6: sr: fix possible use-after-free and null-ptr-deref 2024-02-20T09:17:14+00:00 Vasiliy Kovalev kovalev@altlinux.org 2024-02-15T20:27:17+00:00 5559cea2d5aa3018a5f00dd2aca3427ba09b386b The pernet operations structure for the subsystem must be registered before registering the generic netlink family. Fixes: 915d7e5e5930 ("ipv6: sr: add code base for control plane support of SR-IPv6") Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org> Link: https://lore.kernel.org/r/20240215202717.29815-1-kovalev@altlinux.org Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
The pernet operations structure for the subsystem must be registered
before registering the generic netlink family.

Fixes: 915d7e5e5930 ("ipv6: sr: add code base for control plane support of SR-IPv6")
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Link: https://lore.kernel.org/r/20240215202717.29815-1-kovalev@altlinux.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
ipv6: properly combine dev_base_seq and ipv6.dev_addr_genid 2024-02-18T10:22:27+00:00 Eric Dumazet edumazet@google.com 2024-02-15T17:21:07+00:00 e898e4cd1aab271ca414f9ac6e08e4c761f6913c net->dev_base_seq and ipv6.dev_addr_genid are monotonically increasing. If we XOR their values, we could miss to detect if both values were changed with the same amount. Fixes: 63998ac24f83 ("ipv6: provide addr and netconf dump consistency info") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
net->dev_base_seq and ipv6.dev_addr_genid are monotonically increasing.

If we XOR their values, we could miss to detect if both values
were changed with the same amount.

Fixes: 63998ac24f83 ("ipv6: provide addr and netconf dump consistency info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net-timestamp: make sk_tskey more predictable in error path 2024-02-15T11:04:04+00:00 Vadim Fedorenko vadfed@meta.com 2024-02-13T11:04:28+00:00 488b6d91b07112eaaaa4454332c1480894d4e06e When SOF_TIMESTAMPING_OPT_ID is used to ambiguate timestamped datagrams, the sk_tskey can become unpredictable in case of any error happened during sendmsg(). Move increment later in the code and make decrement of sk_tskey in error path. This solution is still racy in case of multiple threads doing snedmsg() over the very same socket in parallel, but still makes error path much more predictable. Fixes: 09c2d251b707 ("net-timestamp: add key to disambiguate concurrent datagrams") Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Vadim Fedorenko <vadfed@meta.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/20240213110428.1681540-1-vadfed@meta.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
When SOF_TIMESTAMPING_OPT_ID is used to ambiguate timestamped datagrams,
the sk_tskey can become unpredictable in case of any error happened
during sendmsg(). Move increment later in the code and make decrement of
sk_tskey in error path. This solution is still racy in case of multiple
threads doing snedmsg() over the very same socket in parallel, but still
makes error path much more predictable.

Fixes: 09c2d251b707 ("net-timestamp: add key to disambiguate concurrent datagrams")
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240213110428.1681540-1-vadfed@meta.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net: fill in MODULE_DESCRIPTION()s for ipv6 modules 2024-02-09T22:12:01+00:00 Breno Leitao leitao@debian.org 2024-02-08T16:42:40+00:00 92ab08eb63bbf54caebb425ed8908758c98ae8f2 W=1 builds now warn if module is built without a MODULE_DESCRIPTION(). Add descriptions to the IPv6 modules. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20240208164244.3818498-6-leitao@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to the IPv6 modules.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240208164244.3818498-6-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>