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9 daysipv6: avoid overflows in ip6_datagram_send_ctl()Eric Dumazet
[ Upstream commit 4e453375561fc60820e6b9d8ebeb6b3ee177d42e ] Yiming Qian reported : <quote> I believe I found a locally triggerable kernel bug in the IPv6 sendmsg ancillary-data path that can panic the kernel via `skb_under_panic()` (local DoS). The core issue is a mismatch between: - a 16-bit length accumulator (`struct ipv6_txoptions::opt_flen`, type `__u16`) and - a pointer to the *last* provided destination-options header (`opt->dst1opt`) when multiple `IPV6_DSTOPTS` control messages (cmsgs) are provided. - `include/net/ipv6.h`: - `struct ipv6_txoptions::opt_flen` is `__u16` (wrap possible). (lines 291-307, especially 298) - `net/ipv6/datagram.c:ip6_datagram_send_ctl()`: - Accepts repeated `IPV6_DSTOPTS` and accumulates into `opt_flen` without rejecting duplicates. (lines 909-933) - `net/ipv6/ip6_output.c:__ip6_append_data()`: - Uses `opt->opt_flen + opt->opt_nflen` to compute header sizes/headroom decisions. (lines 1448-1466, especially 1463-1465) - `net/ipv6/ip6_output.c:__ip6_make_skb()`: - Calls `ipv6_push_frag_opts()` if `opt->opt_flen` is non-zero. (lines 1930-1934) - `net/ipv6/exthdrs.c:ipv6_push_frag_opts()` / `ipv6_push_exthdr()`: - Push size comes from `ipv6_optlen(opt->dst1opt)` (based on the pointed-to header). (lines 1179-1185 and 1206-1211) 1. `opt_flen` is a 16-bit accumulator: - `include/net/ipv6.h:298` defines `__u16 opt_flen; /* after fragment hdr */`. 2. `ip6_datagram_send_ctl()` accepts *repeated* `IPV6_DSTOPTS` cmsgs and increments `opt_flen` each time: - In `net/ipv6/datagram.c:909-933`, for `IPV6_DSTOPTS`: - It computes `len = ((hdr->hdrlen + 1) << 3);` - It checks `CAP_NET_RAW` using `ns_capable(net->user_ns, CAP_NET_RAW)`. (line 922) - Then it does: - `opt->opt_flen += len;` (line 927) - `opt->dst1opt = hdr;` (line 928) There is no duplicate rejection here (unlike the legacy `IPV6_2292DSTOPTS` path which rejects duplicates at `net/ipv6/datagram.c:901-904`). If enough large `IPV6_DSTOPTS` cmsgs are provided, `opt_flen` wraps while `dst1opt` still points to a large (2048-byte) destination-options header. In the attached PoC (`poc.c`): - 32 cmsgs with `hdrlen=255` => `len = (255+1)*8 = 2048` - 1 cmsg with `hdrlen=0` => `len = 8` - Total increment: `32*2048 + 8 = 65544`, so `(__u16)opt_flen == 8` - The last cmsg is 2048 bytes, so `dst1opt` points to a 2048-byte header. 3. The transmit path sizes headers using the wrapped `opt_flen`: - In `net/ipv6/ip6_output.c:1463-1465`: - `headersize = sizeof(struct ipv6hdr) + (opt ? opt->opt_flen + opt->opt_nflen : 0) + ...;` With wrapped `opt_flen`, `headersize`/headroom decisions underestimate what will be pushed later. 4. When building the final skb, the actual push length comes from `dst1opt` and is not limited by wrapped `opt_flen`: - In `net/ipv6/ip6_output.c:1930-1934`: - `if (opt->opt_flen) proto = ipv6_push_frag_opts(skb, opt, proto);` - In `net/ipv6/exthdrs.c:1206-1211`, `ipv6_push_frag_opts()` pushes `dst1opt` via `ipv6_push_exthdr()`. - In `net/ipv6/exthdrs.c:1179-1184`, `ipv6_push_exthdr()` does: - `skb_push(skb, ipv6_optlen(opt));` - `memcpy(h, opt, ipv6_optlen(opt));` With insufficient headroom, `skb_push()` underflows and triggers `skb_under_panic()` -> `BUG()`: - `net/core/skbuff.c:2669-2675` (`skb_push()` calls `skb_under_panic()`) - `net/core/skbuff.c:207-214` (`skb_panic()` ends in `BUG()`) - The `IPV6_DSTOPTS` cmsg path requires `CAP_NET_RAW` in the target netns user namespace (`ns_capable(net->user_ns, CAP_NET_RAW)`). - Root (or any task with `CAP_NET_RAW`) can trigger this without user namespaces. - An unprivileged `uid=1000` user can trigger this if unprivileged user namespaces are enabled and it can create a userns+netns to obtain namespaced `CAP_NET_RAW` (the attached PoC does this). - Local denial of service: kernel BUG/panic (system crash). - Reproducible with a small userspace PoC. </quote> This patch does not reject duplicated options, as this might break some user applications. Instead, it makes sure to adjust opt_flen and opt_nflen to correctly reflect the size of the current option headers, preventing the overflows and the potential for panics. This applies to IPV6_DSTOPTS, IPV6_HOPOPTS, and IPV6_RTHDR. Specifically: When a new IPV6_DSTOPTS is processed, the length of the old opt->dst1opt is subtracted from opt->opt_flen before adding the new length. When a new IPV6_HOPOPTS is processed, the length of the old opt->dst0opt is subtracted from opt->opt_nflen. When a new Routing Header (IPV6_RTHDR or IPV6_2292RTHDR) is processed, the length of the old opt->srcrt is subtracted from opt->opt_nflen. In the special case within IPV6_2292RTHDR handling where dst1opt is moved to dst0opt, the length of the old opt->dst0opt is subtracted from opt->opt_nflen before the new one is added. Fixes: 333fad5364d6 ("[IPV6]: Support several new sockopt / ancillary data in Advanced API (RFC3542).") Reported-by: Yiming Qian <yimingqian591@gmail.com> Closes: https://lore.kernel.org/netdev/CAL_bE8JNzawgr5OX5m+3jnQDHry2XxhQT5=jThW1zDPtUikRYA@mail.gmail.com/ Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260401154721.3740056-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
9 daysnet: ipv6: flowlabel: defer exclusive option free until RCU teardownZhengchuan Liang
[ Upstream commit 9ca562bb8e66978b53028fa32b1a190708e6a091 ] `ip6fl_seq_show()` walks the global flowlabel hash under the seq-file RCU read-side lock and prints `fl->opt->opt_nflen` when an option block is present. Exclusive flowlabels currently free `fl->opt` as soon as `fl->users` drops to zero in `fl_release()`. However, the surrounding `struct ip6_flowlabel` remains visible in the global hash table until later garbage collection removes it and `fl_free_rcu()` finally tears it down. A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that early `kfree()` and dereference freed option state, triggering a crash in `ip6fl_seq_show()`. Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches the lifetime already required for the enclosing flowlabel while readers can still reach it under RCU. Fixes: d3aedd5ebd4b ("ipv6 flowlabel: Convert hash list to RCU.") Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Co-developed-by: Yuan Tan <yuantan098@gmail.com> Signed-off-by: Yuan Tan <yuantan098@gmail.com> Suggested-by: Xin Liu <bird@lzu.edu.cn> Tested-by: Ren Wei <enjou1224z@gmail.com> Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/07351f0ec47bcee289576f39f9354f4a64add6e4.1774855883.git.zcliangcn@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
9 daysipv6: prevent possible UaF in addrconf_permanent_addr()Paolo Abeni
[ Upstream commit fd63f185979b047fb22a0dfc6bd94d0cab6a6a70 ] The mentioned helper try to warn the user about an exceptional condition, but the message is delivered too late, accessing the ipv6 after its possible deletion. Reorder the statement to avoid the possible UaF; while at it, place the warning outside the idev->lock as it needs no protection. Reported-by: Jakub Kicinski <kuba@kernel.org> Closes: https://sashiko.dev/#/patchset/8c8bfe2e1a324e501f0e15fef404a77443fd8caf.1774365668.git.pabeni%40redhat.com Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Link: https://patch.msgid.link/ef973c3a8cb4f8f1787ed469f3e5391b9fe95aa0.1774601542.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
9 daysip6_tunnel: clear skb2->cb[] in ip4ip6_err()Eric Dumazet
[ Upstream commit 2edfa31769a4add828a7e604b21cb82aaaa05925 ] Oskar Kjos reported the following problem. ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written by the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes IPCB(skb2) to __ip_options_echo(), which interprets that cb[] region as struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff at offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr value. __ip_options_echo() then reads optlen from attacker-controlled packet data at sptr[rr+1] and copies that many bytes into dopt->__data, a fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE). To fix this we clear skb2->cb[], as suggested by Oskar Kjos. Also add minimal IPv4 header validation (version == 4, ihl >= 5). Fixes: c4d3efafcc93 ("[IPV6] IP6TUNNEL: Add support to IPv4 over IPv6 tunnel.") Reported-by: Oskar Kjos <oskar.kjos@hotmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20260326155138.2429480-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
9 daysipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()Eric Dumazet
[ Upstream commit 86ab3e55673a7a49a841838776f1ab18d23a67b5 ] Sashiko AI-review observed: In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2 and passed to icmp6_send(), it uses IP6CB(skb2). IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm at offset 18. If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO). This would scan the inner, attacker-controlled IPv6 packet starting at that offset, potentially returning a fake TLV without checking if the remaining packet length can hold the full 18-byte struct ipv6_destopt_hao. Could mip6_addr_swap() then perform a 16-byte swap that extends past the end of the packet data into skb_shared_info? Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and ip6ip6_err() to prevent this? This patch implements the first suggestion. I am not sure if ip6ip6_err() needs to be changed. A separate patch would be better anyway. Fixes: ca15a078bd90 ("sit: generate icmpv6 error when receiving icmpv4 error") Reported-by: Ido Schimmel <idosch@nvidia.com> Closes: https://sashiko.dev/#/patchset/20260326155138.2429480-1-edumazet%40google.com Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Oskar Kjos <oskar.kjos@hotmail.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20260326202608.2976021-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
9 daysnet/ipv6: ioam6: prevent schema length wraparound in trace fillPengpeng Hou
[ Upstream commit 5e67ba9bb531e1ec6599a82a065dea9040b9ce50 ] ioam6_fill_trace_data() stores the schema contribution to the trace length in a u8. With bit 22 enabled and the largest schema payload, sclen becomes 1 + 1020 / 4, wraps from 256 to 0, and bypasses the remaining-space check. __ioam6_fill_trace_data() then positions the write cursor without reserving the schema area but still copies the 4-byte schema header and the full schema payload, overrunning the trace buffer. Keep sclen in an unsigned int so the remaining-space check and the write cursor calculation both see the full schema length. Fixes: 8c6f6fa67726 ("ipv6: ioam: IOAM Generic Netlink API") Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn> Reviewed-by: Justin Iurman <justin.iurman@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
9 daysnet: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields ↵Yochai Eisenrich
to zero to prevent an info-leak [ Upstream commit ae05340ccaa9d347fe85415609e075545bec589f ] When processing Router Advertisements with user options the kernel builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct has three padding fields that are never zeroed and can leak kernel data The fix is simple, just zeroes the padding fields. Fixes: 31910575a9de ("[IPv6]: Export userland ND options through netlink (RDNSS support)") Signed-off-by: Yochai Eisenrich <echelonh@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20260324224925.2437775-1-echelonh@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-04-02netfilter: ip6t_rt: reject oversized addrnr in rt_mt6_check()Ren Wei
[ Upstream commit 9d3f027327c2fa265f7f85ead41294792c3296ed ] Reject rt match rules whose addrnr exceeds IP6T_RT_HOPS. rt_mt6() expects addrnr to stay within the bounds of rtinfo->addrs[]. Validate addrnr during rule installation so malformed rules are rejected before the match logic can use an out-of-range value. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Co-developed-by: Yuan Tan <yuantan098@gmail.com> Signed-off-by: Yuan Tan <yuantan098@gmail.com> Suggested-by: Xin Liu <bird@lzu.edu.cn> Tested-by: Yuhang Zheng <z1652074432@gmail.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-04-02ipv6: Don't remove permanent routes with exceptions from tb6_gc_hlist.Kuniyuki Iwashima
[ Upstream commit 4be7b99c253f0c85a255cc1db7127ba3232dfa30 ] The cited commit mechanically put fib6_remove_gc_list() just after every fib6_clean_expires() call. When a temporary route is promoted to a permanent route, there may already be exception routes tied to it. If fib6_remove_gc_list() removes the route from tb6_gc_hlist, such exception routes will no longer be aged. Let's replace fib6_remove_gc_list() with a new helper fib6_may_remove_gc_list() and use fib6_age_exceptions() there. Note that net->ipv6 is only compiled when CONFIG_IPV6 is enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded. Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-04-02ipv6: Remove permanent routes from tb6_gc_hlist when all exceptions expire.Kuniyuki Iwashima
[ Upstream commit 6af51e9f31336632263c4680b2a3712295103e1f ] Commit 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.") introduced a per-table GC list and changed GC to iterate over that list instead of traversing the entire route table. However, it forgot to add permanent routes to tb6_gc_hlist when exception routes are added. Commit cfe82469a00f ("ipv6: add exception routes to GC list in rt6_insert_exception") fixed that issue but introduced another one. Even after all exception routes expire, the permanent routes remain in tb6_gc_hlist, potentially negating the performance benefits intended by the initial change. Let's count gc_args->more before and after rt6_age_exceptions() and remove the permanent route when the delta is 0. Note that the next patch will reuse fib6_age_exceptions(). Fixes: cfe82469a00f ("ipv6: add exception routes to GC list in rt6_insert_exception") Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260320072317.2561779-2-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-04-02esp: fix skb leak with espintcp and async cryptoSabrina Dubroca
[ Upstream commit 0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2 ] When the TX queue for espintcp is full, esp_output_tail_tcp will return an error and not free the skb, because with synchronous crypto, the common xfrm output code will drop the packet for us. With async crypto (esp_output_done), we need to drop the skb when esp_output_tail_tcp returns an error. Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-25ipv6: add NULL checks for idev in SRv6 pathsMinhong He
[ Upstream commit 06413793526251870e20402c39930804f14d59c0 ] __in6_dev_get() can return NULL when the device has no IPv6 configuration (e.g. MTU < IPV6_MIN_MTU or after NETDEV_UNREGISTER). Add NULL checks for idev returned by __in6_dev_get() in both seg6_hmac_validate_skb() and ipv6_srh_rcv() to prevent potential NULL pointer dereferences. Fixes: 1ababeba4a21 ("ipv6: implement dataplane support for rthdr type 4 (Segment Routing Header)") Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Signed-off-by: Minhong He <heminhong@kylinos.cn> Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it> Link: https://patch.msgid.link/20260316073301.106643-1-heminhong@kylinos.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-19net/tcp-md5: Fix MAC comparison to be constant-timeEric Biggers
commit 46d0d6f50dab706637f4c18a470aac20a21900d3 upstream. To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.") Fixes: 658ddaaf6694 ("tcp: md5: RST: getting md5 key from listener") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org> Link: https://patch.msgid.link/20260302203409.13388-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-03-12net: ipv6: fix panic when IPv4 route references loopback IPv6 nexthopJiayuan Chen
[ Upstream commit 21ec92774d1536f71bdc90b0e3d052eff99cf093 ] When a standalone IPv6 nexthop object is created with a loopback device (e.g., "ip -6 nexthop add id 100 dev lo"), fib6_nh_init() misclassifies it as a reject route. This is because nexthop objects have no destination prefix (fc_dst=::), causing fib6_is_reject() to match any loopback nexthop. The reject path skips fib_nh_common_init(), leaving nhc_pcpu_rth_output unallocated. If an IPv4 route later references this nexthop, __mkroute_output() dereferences NULL nhc_pcpu_rth_output and panics. Simplify the check in fib6_nh_init() to only match explicit reject routes (RTF_REJECT) instead of using fib6_is_reject(). The loopback promotion heuristic in fib6_is_reject() is handled separately by ip6_route_info_create_nh(). After this change, the three cases behave as follows: 1. Explicit reject route ("ip -6 route add unreachable 2001:db8::/64"): RTF_REJECT is set, enters reject path, skips fib_nh_common_init(). No behavior change. 2. Implicit loopback reject route ("ip -6 route add 2001:db8::/32 dev lo"): RTF_REJECT is not set, takes normal path, fib_nh_common_init() is called. ip6_route_info_create_nh() still promotes it to reject afterward. nhc_pcpu_rth_output is allocated but unused, which is harmless. 3. Standalone nexthop object ("ip -6 nexthop add id 100 dev lo"): RTF_REJECT is not set, takes normal path, fib_nh_common_init() is called. nhc_pcpu_rth_output is properly allocated, fixing the crash when IPv4 routes reference this nexthop. Suggested-by: Ido Schimmel <idosch@nvidia.com> Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects") Reported-by: syzbot+334190e097a98a1b81bb@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/698f8482.a70a0220.2c38d7.00ca.GAE@google.com/T/ Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260304113817.294966-2-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12tcp: secure_seq: add back ports to TS offsetEric Dumazet
[ Upstream commit 165573e41f2f66ef98940cf65f838b2cb575d9d1 ] This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset. Fixes: 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") Reported-by: Zhouyan Deng <dengzhouyan_nwpu@163.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Florian Westphal <fw@strlen.de> Link: https://patch.msgid.link/20260302205527.1982836-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()Jakub Kicinski
[ Upstream commit 2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a ] l3mdev_master_dev_rcu() can return NULL when the slave device is being un-slaved from a VRF. All other callers deal with this, but we lost the fallback to loopback in ip6_rt_pcpu_alloc() -> ip6_rt_get_dev_rcu() with commit 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address"). KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418) Call Trace: ip6_pol_route (net/ipv6/route.c:2318) fib6_rule_lookup (net/ipv6/fib6_rules.c:115) ip6_route_output_flags (net/ipv6/route.c:2607) vrf_process_v6_outbound (drivers/net/vrf.c:437) I was tempted to rework the un-slaving code to clear the flag first and insert synchronize_rcu() before we remove the upper. But looks like the explicit fallback to loopback_dev is an established pattern. And I guess avoiding the synchronize_rcu() is nice, too. Fixes: 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address") Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260301194548.927324-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12inet: annotate data-races around isk->inet_numEric Dumazet
[ Upstream commit 29252397bcc1e0a1f85e5c3bee59c325f5c26341 ] UDP/TCP lookups are using RCU, thus isk->inet_num accesses should use READ_ONCE() and WRITE_ONCE() where needed. Fixes: 3ab5aee7fe84 ("net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260225203545.1512417-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()Qanux
[ Upstream commit 6db8b56eed62baacaf37486e83378a72635c04cc ] On the receive path, __ioam6_fill_trace_data() uses trace->nodelen to decide how much data to write for each node. It trusts this field as-is from the incoming packet, with no consistency check against trace->type (the 24-bit field that tells which data items are present). A crafted packet can set nodelen=0 while setting type bits 0-21, causing the function to write ~100 bytes past the allocated region (into skb_shared_info), which corrupts adjacent heap memory and leads to a kernel panic. Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to derive the expected nodelen from the type field, and use it: - in ioam6_iptunnel.c (send path, existing validation) to replace the open-coded computation; - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose nodelen is inconsistent with the type field, before any data is written. Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to 0xff1ffc00). Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace") Cc: stable@vger.kernel.org Signed-off-by: Junxi Qian <qjx1298677004@gmail.com> Reviewed-by: Justin Iurman <justin.iurman@gmail.com> Link: https://patch.msgid.link/20260211040412.86195-1-qjx1298677004@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04udplite: Fix null-ptr-deref in __udp_enqueue_schedule_skb().Kuniyuki Iwashima
[ Upstream commit 470c7ca2b4c3e3a51feeb952b7f97a775b5c49cd ] syzbot reported null-ptr-deref of udp_sk(sk)->udp_prod_queue. [0] Since the cited commit, udp_lib_init_sock() can fail, as can udp_init_sock() and udpv6_init_sock(). Let's handle the error in udplite_sk_init() and udplitev6_sk_init(). [0]: BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:82 [inline] BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] BUG: KASAN: null-ptr-deref in __udp_enqueue_schedule_skb+0x151/0x1480 net/ipv4/udp.c:1719 Read of size 4 at addr 0000000000000008 by task syz.2.18/2944 CPU: 1 UID: 0 PID: 2944 Comm: syz.2.18 Not tainted syzkaller #0 PREEMPTLAZY Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: <IRQ> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 kasan_report+0xa2/0xe0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] __udp_enqueue_schedule_skb+0x151/0x1480 net/ipv4/udp.c:1719 __udpv6_queue_rcv_skb net/ipv6/udp.c:795 [inline] udpv6_queue_rcv_one_skb+0xa2e/0x1ad0 net/ipv6/udp.c:906 udp6_unicast_rcv_skb+0x227/0x380 net/ipv6/udp.c:1064 ip6_protocol_deliver_rcu+0xe17/0x1540 net/ipv6/ip6_input.c:438 ip6_input_finish+0x191/0x350 net/ipv6/ip6_input.c:489 NF_HOOK+0x354/0x3f0 include/linux/netfilter.h:318 ip6_input+0x16c/0x2b0 net/ipv6/ip6_input.c:500 NF_HOOK+0x354/0x3f0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6149 [inline] __netif_receive_skb+0xd3/0x370 net/core/dev.c:6262 process_backlog+0x4d6/0x1160 net/core/dev.c:6614 __napi_poll+0xae/0x320 net/core/dev.c:7678 napi_poll net/core/dev.c:7741 [inline] net_rx_action+0x60d/0xdc0 net/core/dev.c:7893 handle_softirqs+0x209/0x8d0 kernel/softirq.c:622 do_softirq+0x52/0x90 kernel/softirq.c:523 </IRQ> <TASK> __local_bh_enable_ip+0xe7/0x120 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline] __dev_queue_xmit+0x109c/0x2dc0 net/core/dev.c:4856 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x158/0x4e0 net/ipv6/ip6_output.c:219 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x342/0x580 net/ipv6/ip6_output.c:246 ip6_send_skb+0x1d7/0x3c0 net/ipv6/ip6_output.c:1984 udp_v6_send_skb+0x9a5/0x1770 net/ipv6/udp.c:1442 udp_v6_push_pending_frames+0xa2/0x140 net/ipv6/udp.c:1469 udpv6_sendmsg+0xfe0/0x2830 net/ipv6/udp.c:1759 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xe5/0x270 net/socket.c:742 __sys_sendto+0x3eb/0x580 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0xf20 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f67b4d9c629 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f67b5c98028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f67b5015fa0 RCX: 00007f67b4d9c629 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f67b4e32b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000040000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f67b5016038 R14: 00007f67b5015fa0 R15: 00007ffe3cb66dd8 </TASK> Fixes: b650bf0977d3 ("udp: remove busylock and add per NUMA queues") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260219173142.310741-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04tcp: fix potential race in tcp_v6_syn_recv_sock()Eric Dumazet
[ Upstream commit 858d2a4f67ff69e645a43487ef7ea7f28f06deae ] Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+937b5bbb6a815b3e5d0b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/69949275.050a0220.2eeac1.0145.GAE@google.com/ Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260217161205.2079883-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04xfrm6: fix uninitialized saddr in xfrm6_get_saddr()Jiayuan Chen
[ Upstream commit 1799d8abeabc68ec05679292aaf6cba93b343c05 ] xfrm6_get_saddr() does not check the return value of ipv6_dev_get_saddr(). When ipv6_dev_get_saddr() fails to find a suitable source address (returns -EADDRNOTAVAIL), saddr->in6 is left uninitialized, but xfrm6_get_saddr() still returns 0 (success). This causes the caller xfrm_tmpl_resolve_one() to use the uninitialized address in xfrm_state_find(), triggering KMSAN warning: ===================================================== BUG: KMSAN: uninit-value in xfrm_state_find+0x2424/0xa940 xfrm_state_find+0x2424/0xa940 xfrm_resolve_and_create_bundle+0x906/0x5a20 xfrm_lookup_with_ifid+0xcc0/0x3770 xfrm_lookup_route+0x63/0x2b0 ip_route_output_flow+0x1ce/0x270 udp_sendmsg+0x2ce1/0x3400 inet_sendmsg+0x1ef/0x2a0 __sock_sendmsg+0x278/0x3d0 __sys_sendto+0x593/0x720 __x64_sys_sendto+0x130/0x200 x64_sys_call+0x332b/0x3e70 do_syscall_64+0xd3/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f Local variable tmp.i.i created at: xfrm_resolve_and_create_bundle+0x3e3/0x5a20 xfrm_lookup_with_ifid+0xcc0/0x3770 ===================================================== Fix by checking the return value of ipv6_dev_get_saddr() and propagating the error. Fixes: a1e59abf8249 ("[XFRM]: Fix wildcard as tunnel source") Reported-by: syzbot+e136d86d34b42399a8b1@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68bf1024.a70a0220.7a912.02c2.GAE@google.com/T/ Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04ipv6: exthdrs: annotate data-race over multiple sysctlEric Dumazet
[ Upstream commit 978b67d28358b0b4eacfa94453d1ad4e09b123ad ] Following four sysctls can change under us, add missing READ_ONCE(). - ipv6.sysctl.max_dst_opts_len - ipv6.sysctl.max_dst_opts_cnt - ipv6.sysctl.max_hbh_opts_len - ipv6.sysctl.max_hbh_opts_cnt Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20260115094141.3124990-8-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04ipv6: annotate data-races in net/ipv6/route.cEric Dumazet
[ Upstream commit f062e8e25102324364aada61b8283356235bc3c1 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04ipv6: annotate data-races over sysctl.flowlabel_reflectEric Dumazet
[ Upstream commit 5ade47c974b46eb2a1279185962a0ffa15dc5450 ] Add missing READ_ONCE() when reading ipv6.sysctl.flowlabel_reflect, as its value can be changed under us. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20260115094141.3124990-6-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-26ipv6: icmp: remove obsolete code in icmpv6_xrlim_allow()Eric Dumazet
[ Upstream commit 0201eedb69b24a6be9b7c1716287a89c4dde2320 ] Following part was needed before the blamed commit, because inet_getpeer_v6() second argument was the prefix. /* Give more bandwidth to wider prefixes. */ if (rt->rt6i_dst.plen < 128) tmo >>= ((128 - rt->rt6i_dst.plen)>>5); Now inet_getpeer_v6() retrieves hosts, we need to remove @tmo adjustement or wider prefixes likes /24 allow 8x more ICMP to be sent for a given ratelimit. As we had this issue for a while, this patch changes net.ipv6.icmp.ratelimit default value from 1000ms to 100ms to avoid potential regressions. Also add a READ_ONCE() when reading net->ipv6.sysctl.icmpv6_time. Fixes: fd0273d7939f ("ipv6: Remove external dependency on rt6i_dst and rt6i_src") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Cc: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20260216142832.3834174-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-26ipv6: Fix out-of-bound access in fib6_add_rt2node().Kuniyuki Iwashima
[ Upstream commit 8244f959e2c125c849e569f5b23ed49804cce695 ] syzbot reported out-of-bound read in fib6_add_rt2node(). [0] When IPv6 route is created with RTA_NH_ID, struct fib6_info does not have the trailing struct fib6_nh. The cited commit started to check !iter->fib6_nh->fib_nh_gw_family to ensure that rt6_qualify_for_ecmp() will return false for iter. If iter->nh is not NULL, rt6_qualify_for_ecmp() returns false anyway. Let's check iter->nh before reading iter->fib6_nh and avoid OOB read. [0]: BUG: KASAN: slab-out-of-bounds in fib6_add_rt2node+0x349c/0x3500 net/ipv6/ip6_fib.c:1142 Read of size 1 at addr ffff8880384ba6de by task syz.0.18/5500 CPU: 0 UID: 0 PID: 5500 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 fib6_add_rt2node+0x349c/0x3500 net/ipv6/ip6_fib.c:1142 fib6_add_rt2node_nh net/ipv6/ip6_fib.c:1363 [inline] fib6_add+0x910/0x18c0 net/ipv6/ip6_fib.c:1531 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3957 inet6_rtm_newroute+0x268/0x19e0 net/ipv6/route.c:5660 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9316b9aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd8809b678 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f9316e15fa0 RCX: 00007f9316b9aeb9 RDX: 0000000000000000 RSI: 0000200000004380 RDI: 0000000000000003 RBP: 00007f9316c08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9316e15fac R14: 00007f9316e15fa0 R15: 00007f9316e15fa0 </TASK> Allocated by task 5499: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_noprof+0x40c/0x7e0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x142/0x860 net/ipv6/route.c:3820 ip6_route_add+0x49/0x1b0 net/ipv6/route.c:3949 inet6_rtm_newroute+0x268/0x19e0 net/ipv6/route.c:5660 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: bbf4a17ad9ff ("ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF") Reported-by: syzbot+707d6a5da1ab9e0c6f9d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/698cbfba.050a0220.2eeac1.009d.GAE@google.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de> Reviewed-by: Shigeru Yoshida <syoshida@redhat.com> Link: https://patch.msgid.link/20260211175133.3657034-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-26inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMPEric Dumazet
[ Upstream commit c89477ad79446867394360b29bb801010fc3ff22 ] Yizhou Zhao reported that simply having one RAW socket on protocol IPPROTO_RAW (255) was dangerous. socket(AF_INET, SOCK_RAW, 255); A malicious incoming ICMP packet can set the protocol field to 255 and match this socket, leading to FNHE cache changes. inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST") pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner "man 7 raw" states: A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able to send any IP protocol that is specified in the passed header. Receiving of all IP protocols via IPPROTO_RAW is not possible using raw sockets. Make sure we drop these malicious packets. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn> Link: https://lore.kernel.org/netdev/20251109134600.292125-1-zhaoyz24@mails.tsinghua.edu.cn/ Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20260203192509.682208-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-05ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONFShigeru Yoshida
syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6 route. [0] Commit f72514b3c569 ("ipv6: clear RA flags when adding a static route") introduced logic to clear RTF_ADDRCONF from existing routes when a static route with the same nexthop is added. However, this causes a problem when the existing route has a gateway. When RTF_ADDRCONF is cleared from a route that has a gateway, that route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns true. The issue is that this route was never added to the fib6_siblings list. This leads to a mismatch between the following counts: - The sibling count computed by iterating fib6_next chain, which includes the newly ECMP-eligible route - The actual siblings in fib6_siblings list, which does not include that route When a subsequent ECMP route is added, fib6_add_rt2node() hits BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings) because the counts don't match. Fix this by only clearing RTF_ADDRCONF when the existing route does not have a gateway. Routes without a gateway cannot qualify for ECMP anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing RTF_ADDRCONF on them is safe and matches the original intent of the commit. [0]: kernel BUG at net/ipv6/ip6_fib.c:1217! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217 [...] Call Trace: <TASK> fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946 ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571 inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577 sock_do_ioctl+0xdc/0x300 net/socket.c:1245 sock_ioctl+0x576/0x790 net/socket.c:1366 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: f72514b3c569 ("ipv6: clear RA flags when adding a static route") Reported-by: syzbot+cb809def1baaac68ab92@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=cb809def1baaac68ab92 Tested-by: syzbot+cb809def1baaac68ab92@syzkaller.appspotmail.com Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de> Link: https://patch.msgid.link/20260204095837.1285552-1-syoshida@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-29net: fix segmentation of forwarding fraglist GROJibin Zhang
This patch enhances GSO segment handling by properly checking the SKB_GSO_DODGY flag for frag_list GSO packets, addressing low throughput issues observed when a station accesses IPv4 servers via hotspots with an IPv6-only upstream interface. Specifically, it fixes a bug in GSO segmentation when forwarding GRO packets containing a frag_list. The function skb_segment_list cannot correctly process GRO skbs that have been converted by XLAT, since XLAT only translates the header of the head skb. Consequently, skbs in the frag_list may remain untranslated, resulting in protocol inconsistencies and reduced throughput. To address this, the patch explicitly sets the SKB_GSO_DODGY flag for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers (bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO packets as potentially modified after protocol translation. As a result, GSO segmentation will avoid using skb_segment_list and instead falls back to skb_segment for packets with the SKB_GSO_DODGY flag. This ensures that only safe and fully translated frag_list packets are processed by skb_segment_list, resolving protocol inconsistencies and improving throughput when forwarding GRO packets converted by XLAT. Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com> Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260126152114.1211-1-jibin.zhang@mediatek.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-01-25ipv6: use the right ifindex when replying to icmpv6 from localhostFernando Fernandez Mancera
When replying to a ICMPv6 echo request that comes from localhost address the right output ifindex is 1 (lo) and not rt6i_idev dev index. Use the skb device ifindex instead. This fixes pinging to a local address from localhost source address. $ ping6 -I ::1 2001:1:1::2 -c 3 PING 2001:1:1::2 (2001:1:1::2) from ::1 : 56 data bytes 64 bytes from 2001:1:1::2: icmp_seq=1 ttl=64 time=0.037 ms 64 bytes from 2001:1:1::2: icmp_seq=2 ttl=64 time=0.069 ms 64 bytes from 2001:1:1::2: icmp_seq=3 ttl=64 time=0.122 ms 2001:1:1::2 ping statistics 3 packets transmitted, 3 received, 0% packet loss, time 2032ms rtt min/avg/max/mdev = 0.037/0.076/0.122/0.035 ms Fixes: 1b70d792cf67 ("ipv6: Use rt6i_idev index for echo replies to a local address") Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20260121194409.6749-1-fmancera@suse.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-20ipv6: annotate data-race in ndisc_router_discovery()Eric Dumazet
syzbot found that ndisc_router_discovery() could read and write in6_dev->ra_mtu without holding a lock [1] This looks fine, IFLA_INET6_RA_MTU is best effort. Add READ_ONCE()/WRITE_ONCE() to document the race. Note that we might also reject illegal MTU values (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) in a future patch. [1] BUG: KCSAN: data-race in ndisc_router_discovery / ndisc_router_discovery read to 0xffff888119809c20 of 4 bytes by task 25817 on cpu 1: ndisc_router_discovery+0x151d/0x1c90 net/ipv6/ndisc.c:1558 ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841 icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989 ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79 ... write to 0xffff888119809c20 of 4 bytes by task 25816 on cpu 0: ndisc_router_discovery+0x155a/0x1c90 net/ipv6/ndisc.c:1559 ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841 icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989 ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79 ... value changed: 0x00000000 -> 0xe5400659 Fixes: 49b99da2c9ce ("ipv6: add IFLA_INET6_RA_MTU to expose mtu value") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Rocco Yue <rocco.yue@mediatek.com> Link: https://patch.msgid.link/20260118152941.2563857-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-15Merge tag 'ipsec-2026-01-14' of ↵Paolo Abeni
git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec Steffen Klassert says: ==================== pull request (net): ipsec 2026-01-14 1) Fix inner mode lookup in tunnel mode GSO segmentation. The protocol was taken from the wrong field. 2) Set ipv4 no_pmtu_disc flag only on output SAs. The insertation of input SAs can fail if no_pmtu_disc is set. Please pull or let me know if there are problems. ipsec-2026-01-14 * tag 'ipsec-2026-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec: xfrm: set ipv4 no_pmtu_disc flag only on output sa when direction is set xfrm: Fix inner mode lookup in tunnel mode GSO segmentation ==================== Link: https://patch.msgid.link/20260114121817.1106134-1-steffen.klassert@secunet.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-01-13ipv6: Fix use-after-free in inet6_addr_del().Kuniyuki Iwashima
syzbot reported use-after-free of inet6_ifaddr in inet6_addr_del(). [0] The cited commit accidentally moved ipv6_del_addr() for mngtmpaddr before reading its ifp->flags for temporary addresses in inet6_addr_del(). Let's move ipv6_del_addr() down to fix the UAF. [0]: BUG: KASAN: slab-use-after-free in inet6_addr_del.constprop.0+0x67a/0x6b0 net/ipv6/addrconf.c:3117 Read of size 4 at addr ffff88807b89c86c by task syz.3.1618/9593 CPU: 0 UID: 0 PID: 9593 Comm: syz.3.1618 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 inet6_addr_del.constprop.0+0x67a/0x6b0 net/ipv6/addrconf.c:3117 addrconf_del_ifaddr+0x11e/0x190 net/ipv6/addrconf.c:3181 inet6_ioctl+0x1e5/0x2b0 net/ipv6/af_inet6.c:582 sock_do_ioctl+0x118/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f164cf8f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f164de64038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f164d1e5fa0 RCX: 00007f164cf8f749 RDX: 0000200000000000 RSI: 0000000000008936 RDI: 0000000000000003 RBP: 00007f164d013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f164d1e6038 R14: 00007f164d1e5fa0 R15: 00007ffde15c8288 </TASK> Allocated by task 9593: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] ipv6_add_addr+0x4e3/0x2010 net/ipv6/addrconf.c:1120 inet6_addr_add+0x256/0x9b0 net/ipv6/addrconf.c:3050 addrconf_add_ifaddr+0x1fc/0x450 net/ipv6/addrconf.c:3160 inet6_ioctl+0x103/0x2b0 net/ipv6/af_inet6.c:580 sock_do_ioctl+0x118/0x280 net/socket.c:1254 sock_ioctl+0x227/0x6b0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6099: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free_freelist_hook mm/slub.c:2569 [inline] slab_free_bulk mm/slub.c:6696 [inline] kmem_cache_free_bulk mm/slub.c:7383 [inline] kmem_cache_free_bulk+0x2bf/0x680 mm/slub.c:7362 kfree_bulk include/linux/slab.h:830 [inline] kvfree_rcu_bulk+0x1b7/0x1e0 mm/slab_common.c:1523 kvfree_rcu_drain_ready mm/slab_common.c:1728 [inline] kfree_rcu_monitor+0x1d0/0x2f0 mm/slab_common.c:1801 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Fixes: 00b5b7aab9e42 ("net/ipv6: delete temporary address if mngtmpaddr is removed or unmanaged") Reported-by: syzbot+72e610f4f1a930ca9d8a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/696598e9.050a0220.3be5c5.0009.GAE@google.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Hangbin Liu <liuhangbin@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260113010538.2019411-1-kuniyu@google.com 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>
2026-01-09ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()Eric Dumazet
Blamed commit did not take care of VLAN encapsulations as spotted by syzbot [1]. Use skb_vlan_inet_prepare() instead of pskb_inet_may_pull(). [1] BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] BUG: KMSAN: uninit-value in IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 ip6ip6_dscp_ecn_decapsulate+0x16f/0x1b0 net/ipv6/ip6_tunnel.c:729 __ip6_tnl_rcv+0xed9/0x1b50 net/ipv6/ip6_tunnel.c:860 ip6_tnl_rcv+0xc3/0x100 net/ipv6/ip6_tunnel.c:903 gre_rcv+0x1529/0x1b90 net/ipv6/ip6_gre.c:-1 ip6_protocol_deliver_rcu+0x1c89/0x2c60 net/ipv6/ip6_input.c:438 ip6_input_finish+0x1f4/0x4a0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x9c/0x330 net/ipv6/ip6_input.c:500 ip6_mc_input+0x7ca/0xc10 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x958/0x990 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0xf1/0x3c0 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6139 [inline] __netif_receive_skb+0x1df/0xac0 net/core/dev.c:6252 netif_receive_skb_internal net/core/dev.c:6338 [inline] netif_receive_skb+0x57/0x630 net/core/dev.c:6397 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485 tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4960 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586 __alloc_skb+0x805/0x1040 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6712 sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2995 tun_alloc_skb drivers/net/tun.c:1461 [inline] tun_get_user+0x1142/0x6c60 drivers/net/tun.c:1794 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6465 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Fixes: 8d975c15c0cd ("ip6_tunnel: make sure to pull inner header in __ip6_tnl_rcv()") Reported-by: syzbot+d4dda070f833dc5dc89a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/695e88b2.050a0220.1c677c.036d.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260107163109.4188620-1-edumazet@google.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>
2025-12-29ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()Will Rosenberg
There exists a kernel oops caused by a BUG_ON(nhead < 0) at net/core/skbuff.c:2232 in pskb_expand_head(). This bug is triggered as part of the calipso_skbuff_setattr() routine when skb_cow() is passed headroom > INT_MAX (i.e. (int)(skb_headroom(skb) + len_delta) < 0). The root cause of the bug is due to an implicit integer cast in __skb_cow(). The check (headroom > skb_headroom(skb)) is meant to ensure that delta = headroom - skb_headroom(skb) is never negative, otherwise we will trigger a BUG_ON in pskb_expand_head(). However, if headroom > INT_MAX and delta <= -NET_SKB_PAD, the check passes, delta becomes negative, and pskb_expand_head() is passed a negative value for nhead. Fix the trigger condition in calipso_skbuff_setattr(). Avoid passing "negative" headroom sizes to skb_cow() within calipso_skbuff_setattr() by only using skb_cow() to grow headroom. PoC: Using `netlabelctl` tool: netlabelctl map del default netlabelctl calipso add pass doi:7 netlabelctl map add default address:0::1/128 protocol:calipso,7 Then run the following PoC: int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP); // setup msghdr int cmsg_size = 2; int cmsg_len = 0x60; struct msghdr msg; struct sockaddr_in6 dest_addr; struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1, sizeof(struct cmsghdr) + cmsg_len); msg.msg_name = &dest_addr; msg.msg_namelen = sizeof(dest_addr); msg.msg_iov = NULL; msg.msg_iovlen = 0; msg.msg_control = cmsg; msg.msg_controllen = cmsg_len; msg.msg_flags = 0; // setup sockaddr dest_addr.sin6_family = AF_INET6; dest_addr.sin6_port = htons(31337); dest_addr.sin6_flowinfo = htonl(31337); dest_addr.sin6_addr = in6addr_loopback; dest_addr.sin6_scope_id = 31337; // setup cmsghdr cmsg->cmsg_len = cmsg_len; cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_HOPOPTS; char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr); hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80 sendmsg(fd, &msg, 0); Fixes: 2917f57b6bc1 ("calipso: Allow the lsm to label the skbuff directly.") Suggested-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Will Rosenberg <whrosenb@asu.edu> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://patch.msgid.link/20251219173637.797418-1-whrosenb@asu.edu Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-23erspan: Initialize options_len before referencing options.Frode Nordahl
The struct ip_tunnel_info has a flexible array member named options that is protected by a counted_by(options_len) attribute. The compiler will use this information to enforce runtime bounds checking deployed by FORTIFY_SOURCE string helpers. As laid out in the GCC documentation, the counter must be initialized before the first reference to the flexible array member. After scanning through the files that use struct ip_tunnel_info and also refer to options or options_len, it appears the normal case is to use the ip_tunnel_info_opts_set() helper. Said helper would initialize options_len properly before copying data into options, however in the GRE ERSPAN code a partial update is done, preventing the use of the helper function. Before this change the handling of ERSPAN traffic in GRE tunnels would cause a kernel panic when the kernel is compiled with GCC 15+ and having FORTIFY_SOURCE configured: memcpy: detected buffer overflow: 4 byte write of buffer size 0 Call Trace: <IRQ> __fortify_panic+0xd/0xf erspan_rcv.cold+0x68/0x83 ? ip_route_input_slow+0x816/0x9d0 gre_rcv+0x1b2/0x1c0 gre_rcv+0x8e/0x100 ? raw_v4_input+0x2a0/0x2b0 ip_protocol_deliver_rcu+0x1ea/0x210 ip_local_deliver_finish+0x86/0x110 ip_local_deliver+0x65/0x110 ? ip_rcv_finish_core+0xd6/0x360 ip_rcv+0x186/0x1a0 Cc: stable@vger.kernel.org Link: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-counted_005fby-variable-attribute Reported-at: https://launchpad.net/bugs/2129580 Fixes: bb5e62f2d547 ("net: Add options as a flexible array to struct ip_tunnel_info") Signed-off-by: Frode Nordahl <fnordahl@ubuntu.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20251213101338.4693-1-fnordahl@ubuntu.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-22ip6_gre: make ip6gre_header() robustEric Dumazet
Over the years, syzbot found many ways to crash the kernel in ip6gre_header() [1]. This involves team or bonding drivers ability to dynamically change their dev->needed_headroom and/or dev->hard_header_len In this particular crash mld_newpack() allocated an skb with a too small reserve/headroom, and by the time mld_sendpack() was called, syzbot managed to attach an ip6gre device. [1] skbuff: skb_under_panic: text:ffffffff8a1d69a8 len:136 put:40 head:ffff888059bc7000 data:ffff888059bc6fe8 tail:0x70 end:0x6c0 dev:team0 ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:213 ! <TASK> skb_under_panic net/core/skbuff.c:223 [inline] skb_push+0xc3/0xe0 net/core/skbuff.c:2641 ip6gre_header+0xc8/0x790 net/ipv6/ip6_gre.c:1371 dev_hard_header include/linux/netdevice.h:3436 [inline] neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618 neigh_output include/net/neighbour.h:556 [inline] ip6_finish_output2+0xfb3/0x1480 net/ipv6/ip6_output.c:136 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:220 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 Fixes: c12b395a4664 ("gre: Support GRE over IPv6") Reported-by: syzbot+43a2ebcf2a64b1102d64@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/693b002c.a70a0220.33cd7b.0033.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251211173550.2032674-1-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-04xfrm: Fix inner mode lookup in tunnel mode GSO segmentationJianbo Liu
Commit 61fafbee6cfe ("xfrm: Determine inner GSO type from packet inner protocol") attempted to fix GSO segmentation by reading the inner protocol from XFRM_MODE_SKB_CB(skb)->protocol. This was incorrect because the field holds the inner L4 protocol (TCP/UDP) instead of the required tunnel protocol. Also, the memory location (shared by XFRM_SKB_CB(skb) which could be overwritten by xfrm_replay_overflow()) is prone to corruption. This combination caused the kernel to select the wrong inner mode and get the wrong address family. The correct value is in xfrm_offload(skb)->proto, which is set from the outer tunnel header's protocol field by esp[4|6]_gso_encap(). It is initialized by xfrm[4|6]_tunnel_encap_add() to either IPPROTO_IPIP or IPPROTO_IPV6, using xfrm_af2proto() and correctly reflects the inner packet's address family. Fixes: 61fafbee6cfe ("xfrm: Determine inner GSO type from packet inner protocol") Signed-off-by: Jianbo Liu <jianbol@nvidia.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2025-11-25tcp: introduce icsk->icsk_keepalive_timerEric Dumazet
sk->sk_timer has been used for TCP keepalives. Keepalive timers are not in fast path, we want to use sk->sk_timer storage for retransmit timers, for better cache locality. Create icsk->icsk_keepalive_timer and change keepalive code to no longer use sk->sk_timer. Added space is reclaimed in the following patch. This includes changes to MPTCP, which was also using sk_timer. Alias icsk->mptcp_tout_timer and icsk->icsk_keepalive_timer for inet_sk_diag_fill() sake. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20251124175013.1473655-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25tcp: rename icsk_timeout() to tcp_timeout_expires()Eric Dumazet
In preparation of sk->tcp_timeout_timer introduction, rename icsk_timeout() helper and change its argument to plain 'const struct sock *sk'. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20251124175013.1473655-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.18-rc7). No conflicts, adjacent changes: tools/testing/selftests/net/af_unix/Makefile e1bb28bf13f4 ("selftest: af_unix: Add test for SO_PEEK_OFF.") 45a1cd8346ca ("selftests: af_unix: Add tests for ECONNRESET and EOF semantics") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-18ipv6: clear RA flags when adding a static routeFernando Fernandez Mancera
When an IPv6 Router Advertisement (RA) is received for a prefix, the kernel creates the corresponding on-link route with flags RTF_ADDRCONF and RTF_PREFIX_RT configured and RTF_EXPIRES if lifetime is set. If later a user configures a static IPv6 address on the same prefix the kernel clears the RTF_EXPIRES flag but it doesn't clear the RTF_ADDRCONF and RTF_PREFIX_RT. When the next RA for that prefix is received, the kernel sees the route as RA-learned and wrongly configures back the lifetime. This is problematic because if the route expires, the static address won't have the corresponding on-link route. This fix clears the RTF_ADDRCONF and RTF_PREFIX_RT flags preventing that the lifetime is configured when the next RA arrives. If the static address is deleted, the route becomes RA-learned again. Fixes: 14ef37b6d00e ("ipv6: fix route lookup in addrconf_prefix_rcv()") Reported-by: Garri Djavadyan <g.djavadyan@gmail.com> Closes: https://lore.kernel.org/netdev/ba807d39aca5b4dcf395cc11dca61a130a52cfd3.camel@gmail.com/ Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20251115095939.6967-1-fmancera@suse.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-14ipv6: clean up routes when manually removing address with a lifetimeJakub Kicinski
When an IPv6 address with a finite lifetime (configured with valid_lft and preferred_lft) is manually deleted, the kernel does not clean up the associated prefix route. This results in orphaned routes (marked "proto kernel") remaining in the routing table even after their corresponding address has been deleted. This is particularly problematic on networks using combination of SLAAC and bridges. 1. Machine comes up and performs RA on eth0. 2. User creates a bridge - does an ip -6 addr flush dev eth0; - adds the eth0 under the bridge. 3. SLAAC happens on br0. Even tho the address has "moved" to br0 there will still be a route pointing to eth0, but eth0 is not usable for IP any more. Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20251113031700.3736285-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07tcp: Call tcp_syn_ack_timeout() directly.Kuniyuki Iwashima
Since DCCP has been removed, we do not need to use request_sock_ops.syn_ack_timeout(). Let's call tcp_syn_ack_timeout() directly. Now other function pointers of request_sock_ops are protocol-dependent. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251106003357.273403-2-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert proto callbacks from sockaddr to sockaddr_unsizedKees Cook
Convert struct proto pre_connect(), connect(), bind(), and bind_add() callback function prototypes from struct sockaddr to struct sockaddr_unsized. This does not change per-implementation use of sockaddr for passing around an arbitrarily sized sockaddr struct. Those will be addressed in future patches. Additionally removes the no longer referenced struct sockaddr from include/net/inet_common.h. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-5-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert proto_ops connect() callbacks to use sockaddr_unsizedKees Cook
Update all struct proto_ops connect() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert proto_ops bind() callbacks to use sockaddr_unsizedKees Cook
Update all struct proto_ops bind() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-30xfrm: Determine inner GSO type from packet inner protocolJianbo Liu
The GSO segmentation functions for ESP tunnel mode (xfrm4_tunnel_gso_segment and xfrm6_tunnel_gso_segment) were determining the inner packet's L2 protocol type by checking the static x->inner_mode.family field from the xfrm state. This is unreliable. In tunnel mode, the state's actual inner family could be defined by x->inner_mode.family or by x->inner_mode_iaf.family. Checking only the former can lead to a mismatch with the actual packet being processed, causing GSO to create segments with the wrong L2 header type. This patch fixes the bug by deriving the inner mode directly from the packet's inner protocol stored in XFRM_MODE_SKB_CB(skb)->protocol. Instead of replicating the code, this patch modifies the xfrm_ip2inner_mode helper function. It now correctly returns &x->inner_mode if the selector family (x->sel.family) is already specified, thereby handling both specific and AF_UNSPEC cases appropriately. With this change, ESP GSO can use xfrm_ip2inner_mode to get the correct inner mode. It doesn't affect existing callers, as the updated logic now mirrors the checks they were already performing externally. Fixes: 26dbd66eab80 ("esp: choose the correct inner protocol for GSO on inter address family tunnels") Signed-off-by: Jianbo Liu <jianbol@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>