kernel/linux.git/net/ipv6, branch v7.2-rc1

ipv6: fix missing notification for ignore_routes_with_linkdown

2026-06-24T02:12:48+00:00

When changing the ignore_routes_with_linkdown sysctl for a specific interface, the RTM_NEWNETCONF netlink notification was not being emitted to userspace. Fix this by emitting the notification when needed. In addition, fix bogus return value for successful "all" and specific interface write operation leading to a wrong reset of the position pointer. Fixes: 35103d11173b ("net: ipv6 sysctl option to ignore routes when nexthop link is down") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-7-fmancera@suse.de Signed-off-by: Jakub Kicinski

ipv6: fix state corruption during proxy_ndp sysctl restart

2026-06-24T02:12:47+00:00

When handling proxy_ndp, if rtnl_net_trylock() fails, the operation is retried but as the value was already modified by the initial proc_dointvec() call, the restarted syscall will read the newly modified value as the 'old' state. Fix this by taking the RTNL lock before parsing the input value if the operation is a write. Fixes: c92d5491a6d9 ("netconf: add support for IPv6 proxy_ndp") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-6-fmancera@suse.de Signed-off-by: Jakub Kicinski

ipv6: fix error handling in disable_policy sysctl

2026-06-24T02:12:47+00:00

When writing to the disable_policy sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is resetting the position argument even if an error occurred during proc_dointvec() and not only during sysctl restart. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: df789fe75206 ("ipv6: Provide ipv6 version of "disable_policy" sysctl") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-5-fmancera@suse.de Signed-off-by: Jakub Kicinski

ipv6: fix error handling in forwarding sysctl

2026-06-24T02:12:47+00:00

When writing to the forwarding sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. In addition, adjust return code of addrconf_fixup_forwarding() for successful operation. Fixes: b325fddb7f86 ("ipv6: Fix sysctl unregistration deadlock") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-4-fmancera@suse.de Signed-off-by: Jakub Kicinski

ipv6: fix error handling in ignore_routes_with_linkdown sysctl

2026-06-24T02:12:47+00:00

When writing to the ignore_routes_with_linkdown sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: 35103d11173b ("net: ipv6 sysctl option to ignore routes when nexthop link is down") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-3-fmancera@suse.de Signed-off-by: Jakub Kicinski

ipv6: fix error handling in disable_ipv6 sysctl

2026-06-24T02:12:47+00:00

When writing to the disable_ipv6 sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: 56d417b12e57 ("IPv6: Add 'autoconf' and 'disable_ipv6' module parameters") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-2-fmancera@suse.de Signed-off-by: Jakub Kicinski

Merge tag 'ipsec-2026-06-22' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

2026-06-23T23:22:24+00:00

Steffen Klassert says: ==================== pull request (net): ipsec 2026-06-22 1) xfrm: use compat translator only for u64 alignment mismatch Gate the XFRM_USER_COMPAT translator on COMPAT_FOR_U64_ALIGNMENT so 32-bit compat tasks on arches whose 32-bit ABI already matches the native 64-bit layout are no longer rejected with -EOPNOTSUPP. From Sanman Pradhan. 2) net: af_key: initialize alg_key_len for IPComp states Initialize the alg_key_len to 0 in the IPComp branch of pfkey_msg2xfrm_state() so an uninitialized value cannot drive xfrm_alg_len() into a slab-out-of-bounds kmemdup during XFRM_MSG_MIGRATE. From Zijing Yin. 3) xfrm: Fix dev use-after-free in xfrm async resumption Stash the original skb->dev and extend the RCU critical section across xfrm_rcv_cb() and transport_finish() to prevent a tunnel-device UAF and original-device refcount leak when a callback replaces skb->dev. From Dong Chenchen. 4) xfrm: Fix xfrm state cache insertion race Move the state-validity check inside xfrm_state_lock in the input state cache insertion path so a state cannot be killed between the check and the insert. From Herbert Xu. 5) xfrm: annotate data-races around xfrm_policy_count[] and xfrm_policy_default[] Add READ_ONCE()/WRITE_ONCE() annotations on xfrm_policy_count and xfrm_policy_default to silence the KCSAN data race reported on net->xfrm.policy_count. From Eric Dumazet. 6) espintcp: use sk_msg_free_partial to fix partial send Replace the manual skmsg accounting in espintcp with sk_msg_free_partial() so the skmsg stays consistent on every iteration and the partial-send accounting bugs go away. From Sabrina Dubroca. 7) xfrm: validate selector family and prefixlen during match Reject mismatched address families in xfrm_selector_match() and bound prefixlen in addr4_match()/addr_match() to prevent the shift-out-of-bounds syzbot reported when an AF_UNSPEC selector with a large prefixlen is matched against an IPv4 flow. From Eric Dumazet. * tag 'ipsec-2026-06-22' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec: xfrm: validate selector family and prefixlen during match espintcp: use sk_msg_free_partial to fix partial send xfrm: annotate data-races around xfrm_policy_count[] and xfrm_policy_default[] xfrm: Fix xfrm state cache insertion race xfrm: Fix dev use-after-free in xfrm async resumption net: af_key: initialize alg_key_len for IPComp states xfrm: use compat translator only for u64 alignment mismatch ==================== Link: https://patch.msgid.link/20260622075726.29685-1-steffen.klassert@secunet.com Signed-off-by: Jakub Kicinski

ipv6: Fix null-ptr-deref in fib6_nh_mtu_change().

2026-06-23T01:20:09+00:00

fib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and dereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown() clears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has released tb6_lock, so the RA-driven MTU walk can observe a NULL idev and oops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(), but this re-fetch is unguarded; nexthop-backed routes survive addrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is nulled. Return 0 when idev is NULL, matching rt6_mtu_change_route() and the fib6_mtu() fix in commit 5ad509c1fdad ("ipv6: Fix null-ptr-deref in fib6_mtu()."). Oops: general protection fault, ... KASAN: null-ptr-deref in range [0x00000000000002a8-0x00000000000002af] RIP: 0010:fib6_nh_mtu_change+0x203/0x990 rt6_mtu_change_route+0x141/0x1d0 __fib6_clean_all+0xd0/0x160 rt6_mtu_change+0xb4/0x100 ndisc_router_discovery+0x24b5/0x2cb0 icmpv6_rcv+0x12e9/0x1710 ipv6_rcv+0x39b/0x410 Fixes: c0b220cf7d80 ("ipv6: Refactor exception functions") Reported-by: Weiming Shi Signed-off-by: Xiang Mei Reviewed-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260619045334.2427073-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski

Merge tag 'nf-26-06-21' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

2026-06-22T17:33:38+00:00

Pablo Neira Ayuso says: ==================== Netfilter fixes for net The following patchset contains Netfilter fixes for net. This batches fixes for real crashes with trivial/correctness fixes. There is too a rework of the conntrack expectation timeout strategy to deal with a possible race when removing an expectation. 1) Fix the incorrect flowtable timeout extension for entries in hw offload, from Adrian Bente. This is correcting a defect in the functionality, no crash. 2) Hold reference to device under the fake dst in br_netfilter, from Haoze Xie. This is fixing a possible UaF if the device is removed while packet is sitting in nfqueue. 3) Reject template conntrack in xt_cluster, otherwise access to uninitialize conntrack fields are possible leading to WARN_ON due to unset layer 3 protocol. From Wyatt Feng. 4) Make sure the IPv6 tunnel header is in the linear skb data area before pulling. While at it remove incomplete NEXTHDR_DEST support. From Lorenzo Bianconi. This possibly leading to crash if IPv4 header is not in the linear area. 5) Use test_bit_acquire in ipset hash set to avoid reordering of subsequent memory access. This is addressing a LLM related report, no crash has been observed. From Jozsef Kadlecsik. 6) Use test_bit_acquire in ipset bitmap set too, for the same reason as in the previous patch, from Jozsef Kadlecsik. 7) Call kfree_rcu() after rcu_assign_pointer() to address a possible UaF if kfree_rcu() runs inmediately, which to my understanding never happens. Never observed in practise, reported by LLM. Also from Jozsef Kadlecsik. 8) Use disable_delayed_work_sync() instead cancel_delayed_work_sync() to avoid that ipset GC handler re-queues work as reported by LLM. From Jozsef Kadlecsik. This is for correctness. 9) Restore the check in nft_payload for exceeding payloda offset over 2^16. From Florian Westphal. This fixes a silent truncation, not a big deal, but better be assertive and reject it. 10) Validate NFT_META_BRI_IIFHWADDR can only run from bridge prerouting. From Florian Westphal. Harmless but it could allow to read bytes from skb->cb. 11) Zero out destination hardware address during the flowtable path setup, also from Florian. This is a correctness fix, LLM points that possible infoleak can happen but topology to achieve it is not clear. 12) Skip IPv4 options if present when building the IPV4 reject reply. Otherwise bytes in the IPv4 options header can be sent back to origin where the ICMP header is being expected. Again from Florian Westphal. 13) Replace timer API for expectation by GC worker approach. This is implicitly fixing a race between nf_ct_remove_expectations() which might fail to remove the expectation due to timer_del() returning false because timer has expired and callback is being run concurrently. This fix is addressing a crash that has been already reported with a reproducer. 14) Check if br_vlan_get_pvid_rcu() fails, otherwise possible stack infoleak of 4-bytes. From Florian Westphal. * tag 'nf-26-06-21' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf: netfilter: nft_meta_bridge: fix NFT_META_BRI_IIFPVID stack leak netfilter: nf_conntrack_expect: use conntrack GC to reap expectations netfilter: nf_reject: skip iphdr options when looking for icmp header netfilter: nft_flow_offload: zero device address for non-ether case netfilter: nft_meta_bridge: add validate callback for get operations netfilter: nft_payload: reject offsets exceeding 65535 bytes netfilter: ipset: make sure gc is properly stopped netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer() netfilter: ipset: Don't use test_bit() in lockless RCU readers in bitmap types netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types netfilter: flowtable: fix and simplify IP6IP6 tunnel handling netfilter: xt_cluster: reject template conntracks in hash match netfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst netfilter: flowtable: fix offloaded ct timeout never being extended ==================== Link: https://patch.msgid.link/20260620222738.112506-1-pablo@netfilter.org Signed-off-by: Jakub Kicinski

ipv6: ioam: fix type confusion of dst_entry

2026-06-21T22:26:40+00:00

IOAM uses a dummy dst_entry(null_dst) to mark that the destination should not be changed after the transformation. This dst is stored in the IOAM lwt state and may be passed to dst_cache_set_ip6(). However, the IPv6 dst cache path eventually calls rt6_get_cookie(), which treats the dst_entry as part of a struct rt6_info. Since the null_dst was embedded directly as a struct dst_entry in struct ioam6_lwt, this resulted in an invalid cast and rt6_get_cookie() reading fields from the wrong object. In practice, the wrong cookie is not used while dst->obsolete is zero, but rt6_get_cookie() may also access per-cpu value when rt->sernum is zero. In this case, rt->sernum aliases ioam6_lwt::cache::reset_ts, which can become zero, making this a potential invalid pointer access. Fix this by embedding a full struct rt6_info for the dummy IPv6 route and passing its dst member to the dst APIs. Fixes: 47ce7c854563 ("net: ipv6: ioam6: fix double reallocation") Signed-off-by: Jiayuan Chen Reviewed-by: Justin Iurman Link: https://patch.msgid.link/20260618104336.48934-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski