summaryrefslogtreecommitdiff
path: root/net/ipv6/route.c
AgeCommit message (Collapse)Author
2026-02-02ipv6: use dst6_mtu() instead of dst_mtu()Eric Dumazet
When we expect an IPv6 dst, use dst6_mtu() instead of dst_mtu() to save some code space. Due to current dst6_mtu() implementation, only convert users in IPv6 stack. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260130210303.3888261-7-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-19ipv6: annotate data-races in net/ipv6/route.cEric Dumazet
sysctls are read while their values can change, add READ_ONCE() annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20260115094141.3124990-9-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.19-rc6). No conflicts, or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-13dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()Eric Dumazet
syzbot was able to crash the kernel in rt6_uncached_list_flush_dev() in an interesting way [1] Crash happens in list_del_init()/INIT_LIST_HEAD() while writing list->prev, while the prior write on list->next went well. static inline void INIT_LIST_HEAD(struct list_head *list) { WRITE_ONCE(list->next, list); // This went well WRITE_ONCE(list->prev, list); // Crash, @list has been freed. } Issue here is that rt6_uncached_list_del() did not attempt to lock ul->lock, as list_empty(&rt->dst.rt_uncached) returned true because the WRITE_ONCE(list->next, list) happened on the other CPU. We might use list_del_init_careful() and list_empty_careful(), or make sure rt6_uncached_list_del() always grabs the spinlock whenever rt->dst.rt_uncached_list has been set. A similar fix is neeed for IPv4. [1] BUG: KASAN: slab-use-after-free in INIT_LIST_HEAD include/linux/list.h:46 [inline] BUG: KASAN: slab-use-after-free in list_del_init include/linux/list.h:296 [inline] BUG: KASAN: slab-use-after-free in rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline] BUG: KASAN: slab-use-after-free in rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020 Write of size 8 at addr ffff8880294cfa78 by task kworker/u8:14/3450 CPU: 0 UID: 0 PID: 3450 Comm: kworker/u8:14 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: netns cleanup_net Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 INIT_LIST_HEAD include/linux/list.h:46 [inline] list_del_init include/linux/list.h:296 [inline] rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline] rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020 addrconf_ifdown+0x143/0x18a0 net/ipv6/addrconf.c:3853 addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline] call_netdevice_notifiers net/core/dev.c:2282 [inline] netif_close_many+0x29c/0x410 net/core/dev.c:1785 unregister_netdevice_many_notify+0xb50/0x2330 net/core/dev.c:12353 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline] ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248 cleanup_net+0x4de/0x7b0 net/core/net_namespace.c:696 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> Allocated by task 803: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270 dst_alloc+0x105/0x170 net/core/dst.c:89 ip6_dst_alloc net/ipv6/route.c:342 [inline] icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333 mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 20: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x18f/0x8d0 mm/slub.c:6781 dst_destroy+0x235/0x350 net/core/dst.c:121 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core kernel/rcu/tree.c:2857 [inline] rcu_cpu_kthread+0xba5/0x1af0 kernel/rcu/tree.c:2945 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3119 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3239 refdst_drop include/net/dst.h:266 [inline] skb_dst_drop include/net/dst.h:278 [inline] skb_release_head_state+0x71/0x360 net/core/skbuff.c:1156 skb_release_all net/core/skbuff.c:1180 [inline] __kfree_skb net/core/skbuff.c:1196 [inline] sk_skb_reason_drop+0xe9/0x170 net/core/skbuff.c:1234 kfree_skb_reason include/linux/skbuff.h:1322 [inline] tcf_kfree_skb_list include/net/sch_generic.h:1127 [inline] __dev_xmit_skb net/core/dev.c:4260 [inline] __dev_queue_xmit+0x26aa/0x3210 net/core/dev.c:4785 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318 mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 The buggy address belongs to the object at ffff8880294cfa00 which belongs to the cache ip6_dst_cache of size 232 The buggy address is located 120 bytes inside of freed 232-byte region [ffff8880294cfa00, ffff8880294cfae8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x294cf memcg:ffff88803536b781 flags: 0x80000000000000(node=0|zone=1) page_type: f5(slab) raw: 0080000000000000 ffff88802ff1c8c0 ffffea0000bf2bc0 dead000000000006 raw: 0000000000000000 00000000800c000c 00000000f5000000 ffff88803536b781 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 9, tgid 9 (kworker/0:0), ts 91119585830, free_ts 91088628818 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xb10/0x13e0 mm/slub.c:4656 __slab_alloc+0xc6/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] kmem_cache_alloc_noprof+0x101/0x6c0 mm/slub.c:5270 dst_alloc+0x105/0x170 net/core/dst.c:89 ip6_dst_alloc net/ipv6/route.c:342 [inline] icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333 mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 page last free pid 5859 tgid 5859 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x149/0x170 mm/slub.c:3886 __slab_free+0x2af/0x330 mm/slub.c:5952 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270 getname_flags+0xb8/0x540 fs/namei.c:146 getname include/linux/fs.h:2498 [inline] do_sys_openat2+0xbc/0x200 fs/open.c:1426 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 Fixes: 8d0b94afdca8 ("ipv6: Keep track of DST_NOCACHE routes in case of iface down/unregister") Fixes: 78df76a065ae ("ipv4: take rt_uncached_lock only if needed") Reported-by: syzbot+179fc225724092b8b2b2@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6964cdf2.050a0220.eaf7.009d.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260112103825.3810713-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-13ipv6: Allow for nexthop device mismatch with "onlink"Ido Schimmel
IPv4 allows for a nexthop device mismatch when the "onlink" keyword is specified: # ip link add name dummy1 up type dummy # ip address add 192.0.2.1/24 dev dummy1 # ip link add name dummy2 up type dummy # ip route add 198.51.100.0/24 nexthop via 192.0.2.2 dev dummy2 Error: Nexthop has invalid gateway. # ip route add 198.51.100.0/24 nexthop via 192.0.2.2 dev dummy2 onlink # echo $? 0 This seems to be consistent with the description of "onlink" in the ip-route man page: "Pretend that the nexthop is directly attached to this link, even if it does not match any interface prefix". On the other hand, IPv6 rejects a nexthop device mismatch, even when "onlink" is specified: # ip link add name dummy1 up type dummy # ip address add 2001:db8:1::1/64 dev dummy1 # ip link add name dummy2 up type dummy # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 RTNETLINK answers: No route to host # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 onlink Error: Nexthop has invalid gateway or device mismatch. This is intentional according to commit fc1e64e1092f ("net/ipv6: Add support for onlink flag") which added IPv6 "onlink" support and states that "any unicast gateway is allowed as long as the gateway is not a local address and if it resolves it must match the given device". The condition was later relaxed in commit 4ed591c8ab44 ("net/ipv6: Allow onlink routes to have a device mismatch if it is the default route") to allow for a nexthop device mismatch if the gateway address is resolved via the default route: # ip link add name dummy1 up type dummy # ip route add ::/0 dev dummy1 # ip link add name dummy2 up type dummy # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 RTNETLINK answers: No route to host # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 onlink # echo $? 0 While the decision to forbid a nexthop device mismatch in IPv6 seems to be intentional, it is unclear why it was made. Especially when it differs from IPv4 and seems to go against the intended behavior of "onlink". Therefore, relax the condition further and allow for a nexthop device mismatch when "onlink" is specified: # ip link add name dummy1 up type dummy # ip address add 2001:db8:1::1/64 dev dummy1 # ip link add name dummy2 up type dummy # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 onlink # echo $? 0 The motivating use case is the fact that FRR would like to be able to configure overlay routes of the following form: # ip route add <host-Z> vrf <VRF> encap ip id <ID> src <VTEP-A> dst <VTEP-Z> via <VTEP-Z> dev vxlan0 onlink Where vxlan0 is in the default VRF in which "VTEP-Z" is reachable via one of the underlay routes (e.g., via swpX). Without this patch, the above only works with IPv4, but not with IPv6. Reviewed-by: Petr Machata <petrm@nvidia.com> Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260111120813.159799-5-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-30ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RTJiayuan Chen
On PREEMPT_RT kernels, after rt6_get_pcpu_route() returns NULL, the current task can be preempted. Another task running on the same CPU may then execute rt6_make_pcpu_route() and successfully install a pcpu_rt entry. When the first task resumes execution, its cmpxchg() in rt6_make_pcpu_route() will fail because rt6i_pcpu is no longer NULL, triggering the BUG_ON(prev). It's easy to reproduce it by adding mdelay() after rt6_get_pcpu_route(). Using preempt_disable/enable is not appropriate here because ip6_rt_pcpu_alloc() may sleep. Fix this by handling the cmpxchg() failure gracefully on PREEMPT_RT: free our allocation and return the existing pcpu_rt installed by another task. The BUG_ON is replaced by WARN_ON_ONCE for non-PREEMPT_RT kernels where such races should not occur. Link: https://syzkaller.appspot.com/bug?extid=9b35e9bc0951140d13e6 Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.") Reported-by: syzbot+9b35e9bc0951140d13e6@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/6918cd88.050a0220.1c914e.0045.GAE@google.com/T/ Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Link: https://patch.msgid.link/20251223051413.124687-1-jiayuan.chen@linux.dev Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18ipv6: make ipv6_pinfo.daddr_cache a booleanEric Dumazet
ipv6_pinfo.daddr_cache is either NULL or &sk->sk_v6_daddr We do not need 8 bytes, a boolean is enough. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250916160951.541279-3-edumazet@google.com Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18ipv6: make ipv6_pinfo.saddr_cache a booleanEric Dumazet
ipv6_pinfo.saddr_cache is either NULL or &np->saddr. We do not need 8 bytes, a boolean is enough. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250916160951.541279-2-edumazet@google.com Reviewed-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-08-29ipv6: start using dst_dev_rcu()Eric Dumazet
Refactor icmpv6_xrlim_allow() and ip6_dst_hoplimit() so that we acquire rcu_read_lock() a bit longer to be able to use dst_dev_rcu() instead of dst_dev(). __ip6_rt_update_pmtu() and rt6_do_redirect can directly use dst_dev_rcu() in sections already holding rcu_read_lock(). Small changes to use dst_dev_net_rcu() in ip6_default_advmss(), ipv6_sock_ac_join(), ip6_mc_find_dev() and ndisc_send_skb(). Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20250828195823.3958522-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-30Merge tag 'bpf-next-6.17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Pull bpf updates from Alexei Starovoitov: - Remove usermode driver (UMD) framework (Thomas Weißschuh) - Introduce Strongly Connected Component (SCC) in the verifier to detect loops and refine register liveness (Eduard Zingerman) - Allow 'void *' cast using bpf_rdonly_cast() and corresponding '__arg_untrusted' for global function parameters (Eduard Zingerman) - Improve precision for BPF_ADD and BPF_SUB operations in the verifier (Harishankar Vishwanathan) - Teach the verifier that constant pointer to a map cannot be NULL (Ihor Solodrai) - Introduce BPF streams for error reporting of various conditions detected by BPF runtime (Kumar Kartikeya Dwivedi) - Teach the verifier to insert runtime speculation barrier (lfence on x86) to mitigate speculative execution instead of rejecting the programs (Luis Gerhorst) - Various improvements for 'veristat' (Mykyta Yatsenko) - For CONFIG_DEBUG_KERNEL config warn on internal verifier errors to improve bug detection by syzbot (Paul Chaignon) - Support BPF private stack on arm64 (Puranjay Mohan) - Introduce bpf_cgroup_read_xattr() kfunc to read xattr of cgroup's node (Song Liu) - Introduce kfuncs for read-only string opreations (Viktor Malik) - Implement show_fdinfo() for bpf_links (Tao Chen) - Reduce verifier's stack consumption (Yonghong Song) - Implement mprog API for cgroup-bpf programs (Yonghong Song) * tag 'bpf-next-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (192 commits) selftests/bpf: Migrate fexit_noreturns case into tracing_failure test suite selftests/bpf: Add selftest for attaching tracing programs to functions in deny list bpf: Add log for attaching tracing programs to functions in deny list bpf: Show precise rejected function when attaching fexit/fmod_ret to __noreturn functions bpf: Fix various typos in verifier.c comments bpf: Add third round of bounds deduction selftests/bpf: Test invariants on JSLT crossing sign selftests/bpf: Test cross-sign 64bits range refinement selftests/bpf: Update reg_bound range refinement logic bpf: Improve bounds when s64 crosses sign boundary bpf: Simplify bounds refinement from s32 selftests/bpf: Enable private stack tests for arm64 bpf, arm64: JIT support for private stack bpf: Move bpf_jit_get_prog_name() to core.c bpf, arm64: Fix fp initialization for exception boundary umd: Remove usermode driver framework bpf/preload: Don't select USERMODE_DRIVER selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure selftests/bpf: Increase xdp data size for arm64 64K page size ...
2025-07-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Merge in late fixes to prepare for the 6.17 net-next PR. Conflicts: net/core/neighbour.c 1bbb76a89948 ("neighbour: Fix null-ptr-deref in neigh_flush_dev().") 13a936bb99fb ("neighbour: Protect tbl->phash_buckets[] with a dedicated mutex.") 03dc03fa0432 ("neighbor: Add NTF_EXT_VALIDATED flag for externally validated entries") Adjacent changes: drivers/net/usb/usbnet.c 0d9cfc9b8cb1 ("net: usbnet: Avoid potential RCU stall on LINK_CHANGE event") 2c04d279e857 ("net: usb: Convert tasklet API to new bottom half workqueue mechanism") net/ipv6/route.c 31d7d67ba127 ("ipv6: annotate data-races around rt->fib6_nsiblings") 1caf27297215 ("ipv6: adopt dst_dev() helper") 3b3ccf9ed05e ("net: Remove unnecessary NULL check for lwtunnel_fill_encap()") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-26ipv6: annotate data-races around rt->fib6_nsiblingsEric Dumazet
rt->fib6_nsiblings can be read locklessly, add corresponding READ_ONCE() and WRITE_ONCE() annotations. Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250725140725.3626540-5-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-26ipv6: fix possible infinite loop in fib6_info_uses_dev()Eric Dumazet
fib6_info_uses_dev() seems to rely on RCU without an explicit protection. Like the prior fix in rt6_nlmsg_size(), we need to make sure fib6_del_route() or fib6_add_rt2node() have not removed the anchor from the list, or we risk an infinite loop. Fixes: d9ccb18f83ea ("ipv6: Fix soft lockups in fib6_select_path under high next hop churn") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250725140725.3626540-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-26ipv6: prevent infinite loop in rt6_nlmsg_size()Eric Dumazet
While testing prior patch, I was able to trigger an infinite loop in rt6_nlmsg_size() in the following place: list_for_each_entry_rcu(sibling, &f6i->fib6_siblings, fib6_siblings) { rt6_nh_nlmsg_size(sibling->fib6_nh, &nexthop_len); } This is because fib6_del_route() and fib6_add_rt2node() uses list_del_rcu(), which can confuse rcu readers, because they might no longer see the head of the list. Restart the loop if f6i->fib6_nsiblings is zero. Fixes: d9ccb18f83ea ("ipv6: Fix soft lockups in fib6_select_path under high next hop churn") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250725140725.3626540-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-26ipv6: add a retry logic in net6_rt_notify()Eric Dumazet
inet6_rt_notify() can be called under RCU protection only. This means the route could be changed concurrently and rt6_fill_node() could return -EMSGSIZE. Re-size the skb when this happens and retry, removing one WARN_ON() that syzbot was able to trigger: WARNING: CPU: 3 PID: 6291 at net/ipv6/route.c:6342 inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342 Modules linked in: CPU: 3 UID: 0 PID: 6291 Comm: syz.0.77 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342 Code: fc ff ff e8 6d 52 ea f7 e9 47 fc ff ff 48 8b 7c 24 08 4c 89 04 24 e8 5a 52 ea f7 4c 8b 04 24 e9 94 fd ff ff e8 9c fe 84 f7 90 <0f> 0b 90 e9 bd fd ff ff e8 6e 52 ea f7 e9 bb fb ff ff 48 89 df e8 RSP: 0018:ffffc900035cf1d8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffc900035cf540 RCX: ffffffff8a36e790 RDX: ffff88802f7e8000 RSI: ffffffff8a36e9d4 RDI: 0000000000000005 RBP: ffff88803c230f00 R08: 0000000000000005 R09: 00000000ffffffa6 R10: 00000000ffffffa6 R11: 0000000000000001 R12: 00000000ffffffa6 R13: 0000000000000900 R14: ffff888032ea4100 R15: 0000000000000000 FS: 00007fac7b89a6c0(0000) GS:ffff8880d6a20000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac7b899f98 CR3: 0000000034b3f000 CR4: 0000000000352ef0 Call Trace: <TASK> ip6_route_mpath_notify+0xde/0x280 net/ipv6/route.c:5356 ip6_route_multipath_add+0x1181/0x1bd0 net/ipv6/route.c:5536 inet6_rtm_newroute+0xe4/0x1a0 net/ipv6/route.c:5647 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6944 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x58d/0x850 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 Fixes: 169fd62799e8 ("ipv6: Get rid of RTNL for SIOCADDRT and RTM_NEWROUTE.") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://patch.msgid.link/20250725140725.3626540-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-16bpf: Clean up individual BTF_ID codeFeng Yang
Use BTF_ID_LIST_SINGLE(a, b, c) instead of BTF_ID_LIST(a) BTF_ID(b, c) Signed-off-by: Feng Yang <yangfeng@kylinos.cn> Link: https://lore.kernel.org/r/20250710055419.70544-1-yangfeng59949@163.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-07-02ipv6: adopt skb_dst_dev() and skb_dst_dev_net[_rcu]() helpersEric Dumazet
Use the new helpers as a step to deal with potential dst->dev races. v2: fix typo in ipv6_rthdr_rcv() (kernel test robot <lkp@intel.com>) Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250630121934.3399505-10-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-02ipv6: adopt dst_dev() helperEric Dumazet
Use the new helper as a step to deal with potential dst->dev races. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250630121934.3399505-9-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-02net: dst: annotate data-races around dst->lastuseEric Dumazet
(dst_entry)->lastuse is read and written locklessly, add corresponding annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250630121934.3399505-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-02net: dst: annotate data-races around dst->expiresEric Dumazet
(dst_entry)->expires is read and written locklessly, add corresponding annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250630121934.3399505-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-02net: dst: annotate data-races around dst->obsoleteEric Dumazet
(dst_entry)->obsolete is read locklessly, add corresponding annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250630121934.3399505-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-25net: Remove unnecessary NULL check for lwtunnel_fill_encap()Yue Haibing
lwtunnel_fill_encap() has NULL check and return 0, so no need to check before call it. Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250624140015.3929241-1-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-23net: annotate races around sk->sk_uidEric Dumazet
sk->sk_uid can be read while another thread changes its value in sockfs_setattr(). Add sk_uid(const struct sock *sk) helper to factorize the needed READ_ONCE() annotations, and add corresponding WRITE_ONCE() where needed. Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Lorenzo Colitti <lorenzo@google.com> Reviewed-by: Maciej Żenczykowski <maze@google.com> Link: https://patch.msgid.link/20250620133001.4090592-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-17net: ipv6: Add ip6_mr_output()Petr Machata
Multicast routing is today handled in the input path. Locally generated MC packets don't hit the IPMR code today. Thus if a VXLAN remote address is multicast, the driver needs to set an OIF during route lookup. Thus MC routing configuration needs to be kept in sync with the VXLAN FDB and MDB. Ideally, the VXLAN packets would be routed by the MC routing code instead. To that end, this patch adds support to route locally generated multicast packets. The newly-added routines do largely what ip6_mr_input() and ip6_mr_forward() do: make an MR cache lookup to find where to send the packets, and use ip6_output() to send each of them. When no cache entry is found, the packet is punted to the daemon for resolution. Similarly to the IPv4 case in a previous patch, the new logic is contingent on a newly-added IP6CB flag being set. Signed-off-by: Petr Machata <petrm@nvidia.com> Link: https://patch.msgid.link/3bcc034a3ab4d3c291072fff38f78d7fbbeef4e6.1750113335.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-12ipv6: Move fib6_config_validate() to ip6_route_add().Kuniyuki Iwashima
syzkaller created an IPv6 route from a malformed packet, which has a prefix len > 128, triggering the splat below. [0] This is a similar issue fixed by commit 586ceac9acb7 ("ipv6: Restore fib6_config validation for SIOCADDRT."). The cited commit removed fib6_config validation from some callers of ip6_add_route(). Let's move the validation back to ip6_route_add() and ip6_route_multipath_add(). [0]: UBSAN: array-index-out-of-bounds in ./include/net/ipv6.h:616:34 index 20 is out of range for type '__u8 [16]' CPU: 1 UID: 0 PID: 7444 Comm: syz.0.708 Not tainted 6.16.0-rc1-syzkaller-g19272b37aa4f #0 PREEMPT Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff80078a80>] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:132 [<ffffffff8000327a>] show_stack+0x30/0x3c arch/riscv/kernel/stacktrace.c:138 [<ffffffff80061012>] __dump_stack lib/dump_stack.c:94 [inline] [<ffffffff80061012>] dump_stack_lvl+0x12e/0x1a6 lib/dump_stack.c:120 [<ffffffff800610a6>] dump_stack+0x1c/0x24 lib/dump_stack.c:129 [<ffffffff8001c0ea>] ubsan_epilogue+0x14/0x46 lib/ubsan.c:233 [<ffffffff819ba290>] __ubsan_handle_out_of_bounds+0xf6/0xf8 lib/ubsan.c:455 [<ffffffff85b363a4>] ipv6_addr_prefix include/net/ipv6.h:616 [inline] [<ffffffff85b363a4>] ip6_route_info_create+0x8f8/0x96e net/ipv6/route.c:3793 [<ffffffff85b635da>] ip6_route_add+0x2a/0x1aa net/ipv6/route.c:3889 [<ffffffff85b02e08>] addrconf_prefix_route+0x2c4/0x4e8 net/ipv6/addrconf.c:2487 [<ffffffff85b23bb2>] addrconf_prefix_rcv+0x1720/0x1e62 net/ipv6/addrconf.c:2878 [<ffffffff85b92664>] ndisc_router_discovery+0x1a06/0x3504 net/ipv6/ndisc.c:1570 [<ffffffff85b99038>] ndisc_rcv+0x500/0x600 net/ipv6/ndisc.c:1874 [<ffffffff85bc2c18>] icmpv6_rcv+0x145e/0x1e0a net/ipv6/icmp.c:988 [<ffffffff85af6798>] ip6_protocol_deliver_rcu+0x18a/0x1976 net/ipv6/ip6_input.c:436 [<ffffffff85af8078>] ip6_input_finish+0xf4/0x174 net/ipv6/ip6_input.c:480 [<ffffffff85af8262>] NF_HOOK include/linux/netfilter.h:317 [inline] [<ffffffff85af8262>] NF_HOOK include/linux/netfilter.h:311 [inline] [<ffffffff85af8262>] ip6_input+0x16a/0x70c net/ipv6/ip6_input.c:491 [<ffffffff85af8dcc>] ip6_mc_input+0x5c8/0x1268 net/ipv6/ip6_input.c:588 [<ffffffff85af6112>] dst_input include/net/dst.h:469 [inline] [<ffffffff85af6112>] ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] [<ffffffff85af6112>] NF_HOOK include/linux/netfilter.h:317 [inline] [<ffffffff85af6112>] NF_HOOK include/linux/netfilter.h:311 [inline] [<ffffffff85af6112>] ipv6_rcv+0x5ae/0x6e0 net/ipv6/ip6_input.c:309 [<ffffffff85087e84>] __netif_receive_skb_one_core+0x106/0x16e net/core/dev.c:5977 [<ffffffff85088104>] __netif_receive_skb+0x2c/0x144 net/core/dev.c:6090 [<ffffffff850883c6>] netif_receive_skb_internal net/core/dev.c:6176 [inline] [<ffffffff850883c6>] netif_receive_skb+0x1aa/0xbf2 net/core/dev.c:6235 [<ffffffff8328656e>] tun_rx_batched.isra.0+0x430/0x686 drivers/net/tun.c:1485 [<ffffffff8329ed3a>] tun_get_user+0x2952/0x3d6c drivers/net/tun.c:1938 [<ffffffff832a21e0>] tun_chr_write_iter+0xc4/0x21c drivers/net/tun.c:1984 [<ffffffff80b9b9ae>] new_sync_write fs/read_write.c:593 [inline] [<ffffffff80b9b9ae>] vfs_write+0x56c/0xa9a fs/read_write.c:686 [<ffffffff80b9c2be>] ksys_write+0x126/0x228 fs/read_write.c:738 [<ffffffff80b9c42e>] __do_sys_write fs/read_write.c:749 [inline] [<ffffffff80b9c42e>] __se_sys_write fs/read_write.c:746 [inline] [<ffffffff80b9c42e>] __riscv_sys_write+0x6e/0x94 fs/read_write.c:746 [<ffffffff80076912>] syscall_handler+0x94/0x118 arch/riscv/include/asm/syscall.h:112 [<ffffffff8637e31e>] do_trap_ecall_u+0x396/0x530 arch/riscv/kernel/traps.c:341 [<ffffffff863a69e2>] handle_exception+0x146/0x152 arch/riscv/kernel/entry.S:197 Fixes: fa76c1674f2e ("ipv6: Move some validation from ip6_route_info_create() to rtm_to_fib6_config().") Reported-by: syzbot+4c2358694722d304c44e@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6849b8c3.a00a0220.1eb5f5.00f0.GAE@google.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250611193551.2999991-1-kuni1840@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20ipv6: Revert two per-cpu var allocation for RTM_NEWROUTE.Kuniyuki Iwashima
These two commits preallocated two per-cpu variables in ip6_route_info_create() as fib_nh_common_init() and fib6_nh_init() were expected to be called under RCU. * commit d27b9c40dbd6 ("ipv6: Preallocate nhc_pcpu_rth_output in ip6_route_info_create().") * commit 5720a328c3e9 ("ipv6: Preallocate rt->fib6_nh->rt6i_pcpu in ip6_route_info_create().") Now these functions can be called without RCU and can use GFP_KERNEL. Let's revert the commits. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250516022759.44392-8-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20ipv6: Pass gfp_flags down to ip6_route_info_create_nh().Kuniyuki Iwashima
Since commit c4837b9853e5 ("ipv6: Split ip6_route_info_create()."), ip6_route_info_create_nh() uses GFP_ATOMIC as it was expected to be called under RCU. Now, we can call it without RCU and use GFP_KERNEL. Let's pass gfp_flags to ip6_route_info_create_nh(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250516022759.44392-7-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20Revert "ipv6: Factorise ip6_route_multipath_add()."Kuniyuki Iwashima
Commit 71c0efb6d12f ("ipv6: Factorise ip6_route_multipath_add().") split a loop in ip6_route_multipath_add() so that we can put rcu_read_lock() between ip6_route_info_create() and ip6_route_info_create_nh(). We no longer need to do so as ip6_route_info_create_nh() does not require RCU now. Let's revert the commit to simplify the code. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250516022759.44392-6-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20ipv6: Narrow down RCU critical section in inet6_rtm_newroute().Kuniyuki Iwashima
Commit 169fd62799e8 ("ipv6: Get rid of RTNL for SIOCADDRT and RTM_NEWROUTE.") added rcu_read_lock() covering ip6_route_info_create_nh() and __ip6_ins_rt() to guarantee that nexthop and netdev will not go away. However, as reported by syzkaller [0], ip_tun_build_state() calls dst_cache_init() with GFP_KERNEL during the RCU critical section. ip6_route_info_create_nh() fetches nexthop or netdev depending on whether RTA_NH_ID is set, and struct fib6_info holds a refcount of either of them by nexthop_get() or netdev_get_by_index(). netdev_get_by_index() looks up a dev and calls dev_hold() under RCU. So, we need RCU only around nexthop_find_by_id() and nexthop_get() ( and a few more nexthop code). Let's add rcu_read_lock() there and remove rcu_read_lock() in ip6_route_add() and ip6_route_multipath_add(). Now these functions called from fib6_add() need RCU: - inet6_rt_notify() - fib6_drop_pcpu_from() (via fib6_purge_rt()) - rt6_flush_exceptions() (via fib6_purge_rt()) - ip6_ignore_linkdown() (via rt6_multipath_rebalance()) All callers of inet6_rt_notify() need RCU, so rcu_read_lock() is added there. [0]: [ BUG: Invalid wait context ] 6.15.0-rc4-syzkaller-00746-g836b313a14a3 #0 Tainted: G W ---------------------------- syz-executor234/5832 is trying to lock: ffffffff8e021688 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0x284/0x16b0 mm/percpu.c:1782 other info that might help us debug this: context-{5:5} 1 lock held by syz-executor234/5832: 0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] 0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] 0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: ip6_route_add+0x4d/0x2f0 net/ipv6/route.c:3913 stack backtrace: CPU: 0 UID: 0 PID: 5832 Comm: syz-executor234 Tainted: G W 6.15.0-rc4-syzkaller-00746-g836b313a14a3 #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_lock_invalid_wait_context kernel/locking/lockdep.c:4831 [inline] check_wait_context kernel/locking/lockdep.c:4903 [inline] __lock_acquire+0xbcf/0xd20 kernel/locking/lockdep.c:5185 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746 pcpu_alloc_noprof+0x284/0x16b0 mm/percpu.c:1782 dst_cache_init+0x37/0xc0 net/core/dst_cache.c:145 ip_tun_build_state+0x193/0x6b0 net/ipv4/ip_tunnel_core.c:687 lwtunnel_build_state+0x381/0x4c0 net/core/lwtunnel.c:137 fib_nh_common_init+0x129/0x460 net/ipv4/fib_semantics.c:635 fib6_nh_init+0x15e4/0x2030 net/ipv6/route.c:3669 ip6_route_info_create_nh+0x139/0x870 net/ipv6/route.c:3866 ip6_route_add+0xf6/0x2f0 net/ipv6/route.c:3915 inet6_rtm_newroute+0x284/0x1c50 net/ipv6/route.c:5732 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 ____sys_sendmsg+0x505/0x830 net/socket.c:2566 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2655 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 Fixes: 169fd62799e8 ("ipv6: Get rid of RTNL for SIOCADDRT and RTM_NEWROUTE.") Reported-by: syzbot+bcc12d6799364500fbec@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bcc12d6799364500fbec Reported-by: Eric Dumazet <edumazet@google.com> Closes: https://lore.kernel.org/netdev/CANn89i+r1cGacVC_6n3-A-WSkAa_Nr+pmxJ7Gt+oP-P9by2aGw@mail.gmail.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250516022759.44392-4-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20inet: Remove rtnl_is_held arg of lwtunnel_valid_encap_type(_attr)?().Kuniyuki Iwashima
Commit f130a0cc1b4f ("inet: fix lwtunnel_valid_encap_type() lock imbalance") added the rtnl_is_held argument as a temporary fix while I'm converting nexthop and IPv6 routing table to per-netns RTNL or RCU. Now all callers of lwtunnel_valid_encap_type() do not hold RTNL. Let's remove the argument. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250516022759.44392-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-02ipv6: Restore fib6_config validation for SIOCADDRT.Kuniyuki Iwashima
syzkaller reported out-of-bounds read in ipv6_addr_prefix(), where the prefix length was over 128. The cited commit accidentally removed some fib6_config validation from the ioctl path. Let's restore the validation. [0]: BUG: KASAN: slab-out-of-bounds in ip6_route_info_create (./include/net/ipv6.h:616 net/ipv6/route.c:3814) Read of size 1 at addr ff11000138020ad4 by task repro/261 CPU: 3 UID: 0 PID: 261 Comm: repro Not tainted 6.15.0-rc3-00614-g0d15a26b247d #87 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:409 mm/kasan/report.c:521) kasan_report (mm/kasan/report.c:636) ip6_route_info_create (./include/net/ipv6.h:616 net/ipv6/route.c:3814) ip6_route_add (net/ipv6/route.c:3902) ipv6_route_ioctl (net/ipv6/route.c:4523) inet6_ioctl (net/ipv6/af_inet6.c:577) sock_do_ioctl (net/socket.c:1190) sock_ioctl (net/socket.c:1314) __x64_sys_ioctl (fs/ioctl.c:51 fs/ioctl.c:906 fs/ioctl.c:892 fs/ioctl.c:892) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f518fb2de5d 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 73 9f 1b 00 f7 d8 64 89 01 48 RSP: 002b:00007fff14f38d18 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f518fb2de5d RDX: 00000000200015c0 RSI: 000000000000890b RDI: 0000000000000003 RBP: 00007fff14f38d30 R08: 0000000000000800 R09: 0000000000000800 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff14f38e48 R13: 0000000000401136 R14: 0000000000403df0 R15: 00007f518fd3c000 </TASK> Fixes: fa76c1674f2e ("ipv6: Move some validation from ip6_route_info_create() to rtm_to_fib6_config().") Reported-by: syzkaller <syzkaller@googlegroups.com> Reported-by: Yi Lai <yi1.lai@linux.intel.com> Closes: https://lore.kernel.org/netdev/aBAcKDEFoN%2FLntBF@ly-workstation/ Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20250501005335.53683-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-29ip: load balance tcp connections to single dst addr and portWillem de Bruijn
Load balance new TCP connections across nexthops also when they connect to the same service at a single remote address and port. This affects only port-based multipath hashing: fib_multipath_hash_policy 1 or 3. Local connections must choose both a source address and port when connecting to a remote service, in ip_route_connect. This "chicken-and-egg problem" (commit 2d7192d6cbab ("ipv4: Sanitize and simplify ip_route_{connect,newports}()")) is resolved by first selecting a source address, by looking up a route using the zero wildcard source port and address. As a result multiple connections to the same destination address and port have no entropy in fib_multipath_hash. This is not a problem when forwarding, as skb-based hashing has a 4-tuple. Nor when establishing UDP connections, as autobind there selects a port before reaching ip_route_connect. Load balance also TCP, by using a random port in fib_multipath_hash. Port assignment in inet_hash_connect is not atomic with ip_route_connect. Thus ports are unpredictable, effectively random. Implementation details: Do not actually pass a random fl4_sport, as that affects not only hashing, but routing more broadly, and can match a source port based policy route, which existing wildcard port 0 will not. Instead, define a new wildcard flowi flag that is used only for hashing. Selecting a random source is equivalent to just selecting a random hash entirely. But for code clarity, follow the normal 4-tuple hash process and only update this field. fib_multipath_hash can be reached with zero sport from other code paths, so explicitly pass this flowi flag, rather than trying to infer this case in the function itself. Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20250424143549.669426-3-willemdebruijn.kernel@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Get rid of RTNL for SIOCADDRT and RTM_NEWROUTE.Kuniyuki Iwashima
Now we are ready to remove RTNL from SIOCADDRT and RTM_NEWROUTE. The remaining things to do are 1. pass false to lwtunnel_valid_encap_type_attr() 2. use rcu_dereference_rtnl() in fib6_check_nexthop() 3. place rcu_read_lock() before ip6_route_info_create_nh(). Let's complete the RTNL-free conversion. When each CPU-X adds 100000 routes on table-X in a batch concurrently on c7a.metal-48xl EC2 instance with 192 CPUs, without this series: $ sudo ./route_test.sh ... added 19200000 routes (100000 routes * 192 tables). time elapsed: 191577 milliseconds. with this series: $ sudo ./route_test.sh ... added 19200000 routes (100000 routes * 192 tables). time elapsed: 62854 milliseconds. I changed the number of routes in each table (1000 ~ 100000) and consistently saw it finish 3x faster with this series. Note that now every caller of lwtunnel_valid_encap_type() passes false as the last argument, and this can be removed later. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-16-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Factorise ip6_route_multipath_add().Kuniyuki Iwashima
We will get rid of RTNL from RTM_NEWROUTE and SIOCADDRT and rely on RCU to guarantee dev and nexthop lifetime. Then, the RCU section will start before ip6_route_info_create_nh() in ip6_route_multipath_add(), but ip6_route_info_create() is called in the same loop and will sleep. Let's split the loop into ip6_route_mpath_info_create() and ip6_route_mpath_info_create_nh(). Note that ip6_route_info_append() is now integrated into ip6_route_mpath_info_create_nh() because we need to call different free functions for nexthops that passed ip6_route_info_create_nh(). In case of failure, the remaining nexthops that ip6_route_info_create_nh() has not been called for will be freed by ip6_route_mpath_info_cleanup(). OTOH, if a nexthop passes ip6_route_info_create_nh(), it will be linked to a local temporary list, which will be spliced back to rt6_nh_list. In case of failure, these nexthops will be released by fib6_info_release() in ip6_route_multipath_add(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-12-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Rename rt6_nh.next to rt6_nh.list.Kuniyuki Iwashima
ip6_route_multipath_add() allocates struct rt6_nh for each config of multipath routes to link them to a local list rt6_nh_list. struct rt6_nh.next is the list node of each config, so the name is quite misleading. Let's rename it to list. Suggested-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/netdev/c9bee472-c94e-4878-8cc2-1512b2c54db5@redhat.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-11-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Don't pass net to ip6_route_info_append().Kuniyuki Iwashima
net is not used in ip6_route_info_append() after commit 36f19d5b4f99 ("net/ipv6: Remove extra call to ip6_convert_metrics for multipath case"). Let's remove the argument. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://patch.msgid.link/20250418000443.43734-10-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Preallocate nhc_pcpu_rth_output in ip6_route_info_create().Kuniyuki Iwashima
ip6_route_info_create_nh() will be called under RCU. It calls fib_nh_common_init() and allocates nhc->nhc_pcpu_rth_output. As with the reason for rt->fib6_nh->rt6i_pcpu, we want to avoid GFP_ATOMIC allocation for nhc->nhc_pcpu_rth_output under RCU. Let's preallocate it in ip6_route_info_create(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-9-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Preallocate rt->fib6_nh->rt6i_pcpu in ip6_route_info_create().Kuniyuki Iwashima
ip6_route_info_create_nh() will be called under RCU. Then, fib6_nh_init() is also under RCU, but per-cpu memory allocation is very likely to fail with GFP_ATOMIC while bulk-adding IPv6 routes and we would see a bunch of this message in dmesg. percpu: allocation failed, size=8 align=8 atomic=1, atomic alloc failed, no space left percpu: allocation failed, size=8 align=8 atomic=1, atomic alloc failed, no space left Let's preallocate rt->fib6_nh->rt6i_pcpu in ip6_route_info_create(). If something fails before the original memory allocation in fib6_nh_init(), ip6_route_info_create_nh() calls fib6_info_release(), which releases the preallocated per-cpu memory. Note that rt->fib6_nh->rt6i_pcpu is not preallocated when called via ipv6_stub, so we still need alloc_percpu_gfp() in fib6_nh_init(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-8-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Split ip6_route_info_create().Kuniyuki Iwashima
We will get rid of RTNL from RTM_NEWROUTE and SIOCADDRT and rely on RCU to guarantee dev and nexthop lifetime. Then, we want to allocate as much as possible before entering the RCU section. The RCU section will start in the middle of ip6_route_info_create(), and this is problematic for ip6_route_multipath_add() that calls ip6_route_info_create() multiple times. Let's split ip6_route_info_create() into two parts; one for memory allocation and another for nexthop setup. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://patch.msgid.link/20250418000443.43734-7-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Move nexthop_find_by_id() after fib6_info_alloc().Kuniyuki Iwashima
We will get rid of RTNL from RTM_NEWROUTE and SIOCADDRT. Then, we must perform two lookups for nexthop and dev under RCU to guarantee their lifetime. ip6_route_info_create() calls nexthop_find_by_id() first if RTA_NH_ID is specified, and then allocates struct fib6_info. nexthop_find_by_id() must be called under RCU, but we do not want to use GFP_ATOMIC for memory allocation here, which will be likely to fail in ip6_route_multipath_add(). Let's move nexthop_find_by_id() after the memory allocation so that we can later split ip6_route_info_create() into two parts: the sleepable part and the RCU part. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://patch.msgid.link/20250418000443.43734-6-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Check GATEWAY in rtm_to_fib6_multipath_config().Kuniyuki Iwashima
In ip6_route_multipath_add(), we call rt6_qualify_for_ecmp() for each entry. If it returns false, the request fails. rt6_qualify_for_ecmp() returns false if either of the conditions below is true: 1. f6i->fib6_flags has RTF_ADDRCONF 2. f6i->nh is not NULL 3. f6i->fib6_nh->fib_nh_gw_family is AF_UNSPEC 1 is unnecessary because rtm_to_fib6_config() never sets RTF_ADDRCONF to cfg->fc_flags. 2. is equivalent with cfg->fc_nh_id. 3. can be replaced by checking RTF_GATEWAY in the base and each multipath entry because AF_INET6 is set to f6i->fib6_nh->fib_nh_gw_family only when cfg.fc_is_fdb is true or RTF_GATEWAY is set, but the former is always false. These checks do not require RCU and can be done earlier. Let's perform the equivalent checks in rtm_to_fib6_multipath_config(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-5-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Move some validation from ip6_route_info_create() to rtm_to_fib6_config().Kuniyuki Iwashima
ip6_route_info_create() is called from 3 functions: * ip6_route_add() * ip6_route_multipath_add() * addrconf_f6i_alloc() addrconf_f6i_alloc() does not need validation for struct fib6_config in ip6_route_info_create(). ip6_route_multipath_add() calls ip6_route_info_create() for multiple routes with slightly different fib6_config instances, which is copied from the base config passed from userspace. So, we need not validate the same config repeatedly. Let's move such validation into rtm_to_fib6_config(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://patch.msgid.link/20250418000443.43734-4-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Get rid of RTNL for SIOCDELRT and RTM_DELROUTE.Kuniyuki Iwashima
Basically, removing an IPv6 route does not require RTNL because the IPv6 routing tables are protected by per table lock. inet6_rtm_delroute() calls nexthop_find_by_id() to check if the nexthop specified by RTA_NH_ID exists. nexthop uses rbtree and the top-down walk can be safely performed under RCU. ip6_route_del() already relies on RCU and the table lock, but we need to extend the RCU critical section a bit more to cover __ip6_del_rt(). For example, nexthop_for_each_fib6_nh() and inet6_rt_notify() needs RCU. Let's call nexthop_find_by_id() and __ip6_del_rt() under RCU and get rid of RTNL from inet6_rtm_delroute() and SIOCDELRT. Even if the nexthop is removed after rcu_read_unlock() in inet6_rtm_delroute(), __remove_nexthop_fib() cleans up the routes tied to the nexthop, and ip6_route_del() returns -ESRCH. So the request was at least valid as of nexthop_find_by_id(), and it's just a matter of timing. Note that we need to pass false to lwtunnel_valid_encap_type_attr(). The following patches also use the newroute bool. Note also that fib6_get_table() does not require RCU because once allocated fib6_table is not freed until netns dismantle. I will post a follow-up series to convert such callers to RCU-lockless version. [0] Link: https://lore.kernel.org/netdev/20250417174557.65721-1-kuniyu@amazon.com/ #[0] Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-3-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-24ipv6: Validate RTA_GATEWAY of RTA_MULTIPATH in rtm_to_fib6_config().Kuniyuki Iwashima
We will perform RTM_NEWROUTE and RTM_DELROUTE under RCU, and then we want to perform some validation out of the RCU scope. When creating / removing an IPv6 route with RTA_MULTIPATH, inet6_rtm_newroute() / inet6_rtm_delroute() validates RTA_GATEWAY in each multipath entry. Let's do that in rtm_to_fib6_config(). Note that now RTM_DELROUTE returns an error for RTA_MULTIPATH with 0 entries, which was accepted but should result in -EINVAL as RTM_NEWROUTE. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250418000443.43734-2-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.15-rc3). No conflicts. Adjacent changes: tools/net/ynl/pyynl/ynl_gen_c.py 4d07bbf2d456 ("tools: ynl-gen: don't declare loop iterator in place") 7e8ba0c7de2b ("tools: ynl: don't use genlmsghdr in classic netlink") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-16ipv6: Use nlmsg_payload in route fileBreno Leitao
Leverage the new nlmsg_payload() helper to avoid checking for message size and then reading the nlmsg data. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250415-nlmsg_v2-v1-3-a1c75d493fd7@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-10ipv6: add exception routes to GC list in rt6_insert_exceptionXin Long
Commit 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.") introduced a separated list for managing route expiration via the GC timer. However, it missed adding exception routes (created by ip6_rt_update_pmtu() and rt6_do_redirect()) to this GC list. As a result, these exceptions were never considered for expiration and removal, leading to stale entries persisting in the routing table. This patch fixes the issue by calling fib6_add_gc_list() in rt6_insert_exception(), ensuring that exception routes are properly tracked and garbage collected when expired. Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.") Reported-by: Jianlin Shi <jishi@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/837e7506ffb63f47faa2b05d9b85481aad28e1a4.1744134377.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-09ipv6: Align behavior across nexthops during path selectionIdo Schimmel
A nexthop is only chosen when the calculated multipath hash falls in the nexthop's hash region (i.e., the hash is smaller than the nexthop's hash threshold) and when the nexthop is assigned a non-negative score by rt6_score_route(). Commit 4d0ab3a6885e ("ipv6: Start path selection from the first nexthop") introduced an unintentional difference between the first nexthop and the rest when the score is negative. When the first nexthop matches, but has a negative score, the code will currently evaluate subsequent nexthops until one is found with a non-negative score. On the other hand, when a different nexthop matches, but has a negative score, the code will fallback to the nexthop with which the selection started ('match'). Align the behavior across all nexthops and fallback to 'match' when the first nexthop matches, but has a negative score. Fixes: 3d709f69a3e7 ("ipv6: Use hash-threshold instead of modulo-N") Fixes: 4d0ab3a6885e ("ipv6: Start path selection from the first nexthop") Reported-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Closes: https://lore.kernel.org/netdev/67efef607bc41_1ddca82948c@willemb.c.googlers.com.notmuch/ Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20250408084316.243559-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-04ipv6: Do not consider link down nexthops in path selectionIdo Schimmel
Nexthops whose link is down are not supposed to be considered during path selection when the "ignore_routes_with_linkdown" sysctl is set. This is done by assigning them a negative region boundary. However, when comparing the computed hash (unsigned) with the region boundary (signed), the negative region boundary is treated as unsigned, resulting in incorrect nexthop selection. Fix by treating the computed hash as signed. Note that the computed hash is always in range of [0, 2^31 - 1]. Fixes: 3d709f69a3e7 ("ipv6: Use hash-threshold instead of modulo-N") Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250402114224.293392-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-04ipv6: Start path selection from the first nexthopIdo Schimmel
Cited commit transitioned IPv6 path selection to use hash-threshold instead of modulo-N. With hash-threshold, each nexthop is assigned a region boundary in the multipath hash function's output space and a nexthop is chosen if the calculated hash is smaller than the nexthop's region boundary. Hash-threshold does not work correctly if path selection does not start with the first nexthop. For example, if fib6_select_path() is always passed the last nexthop in the group, then it will always be chosen because its region boundary covers the entire hash function's output space. Fix this by starting the selection process from the first nexthop and do not consider nexthops for which rt6_score_route() provided a negative score. Fixes: 3d709f69a3e7 ("ipv6: Use hash-threshold instead of modulo-N") Reported-by: Stanislav Fomichev <stfomichev@gmail.com> Closes: https://lore.kernel.org/netdev/Z9RIyKZDNoka53EO@mini-arch/ Signed-off-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20250402114224.293392-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
generated by cgit v1.2.3 (git 2.25.1) at 2026-08-08 09:09:24 +0000