kernel/linux.git/net/ipv4, branch v6.1.175

tcp: Fix imbalanced icsk_accept_queue count.

2026-06-01T15:39:39+00:00

[ Upstream commit 7eca3292cac7c26dad4c236f51ba225c39a0523f ] When TCP socket migration happens in reqsk_timer_handler(), @sk_listener will be updated with the new listener. When we call __inet_csk_reqsk_queue_drop(), the listener must be the one stored in req->rsk_listener. The cited commit accidentally replaced oreq->rsk_listener with sk_listener, leading to imbalanced icsk_accept_queue count. Let's pass the correct listener to __inet_csk_reqsk_queue_drop(). Fixes: e8c526f2bdf1 ("tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().") Reported-by: Damiano Melotti Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260506035954.1563147-3-kuniyu@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

netfilter: x_tables: unregister the templates first

2026-06-01T15:39:39+00:00

[ Upstream commit d338693d778579b676a61346849bebd892427158 ] When the module is going away we need to zap the template first. Else there is a small race window where userspace could instantiate a new table after the pernet exit function has removed the current table. Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default") Reported-by: Tristan Madani Reviewed-by: Tristan Madani Closes: https://lore.kernel.org/netfilter-devel/20260429175613.1459342-1-tristmd@gmail.com/ Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

ipv4: raw: reject IP_HDRINCL packets with ihl < 5

2026-06-01T15:39:35+00:00

commit 915fab69823a14c170dbaa3b41978768e0fe62fc upstream. raw_send_hdrinc() validates that the caller-supplied IPv4 header fits within the message length: iphlen = iph->ihl * 4; err = -EINVAL; if (iphlen > length) goto error_free; if (iphlen >= sizeof(*iph)) { /* fix up saddr, tot_len, id, csum, transport_header */ } It does not, however, reject ihl < 5. For such a packet the "if (iphlen >= sizeof(*iph))" branch is skipped, leaving the crafted iphdr untouched, but the packet is still handed to __ip_local_out() and onward. Downstream consumers that read iph->ihl assume a sane value: net/ipv4/ah4.c:ah_output() in particular subtracts sizeof(struct iphdr) from top_iph->ihl * 4 and passes the (signed-int-negative, then cast to size_t) result to memcpy(), producing an OOB access of length close to SIZE_MAX and a host kernel panic. An IPv4 header with ihl < 5 is malformed by definition (RFC 791: "Internet Header Length is the length of the internet header in 32 bit words ... Note that the minimum value for a correct header is 5."). The kernel should not be willing to inject such a packet into its own output path. Reject "iphlen < sizeof(*iph)" alongside the existing "iphlen > length" check. This matches the principle that locally constructed packets that re-enter the IP stack must pass the same basic sanity tests that a foreign packet would be subjected to. Once this lands, the "if (iphlen >= sizeof(*iph))" wrapper around the fixup branch becomes redundant; left in place to keep the patch minimal and backport-friendly. A follow-up can unwrap it. Note that commit 86f4c90a1c5c ("ipv4, ipv6: ensure raw socket message is big enough to hold an IP header") ensures the message buffer is large enough to hold an iphdr, but does not constrain the self-reported iph->ihl. Reachability: the malformed packet source is any caller with CAP_NET_RAW, including an unprivileged process in a user+net namespace on a kernel with CONFIG_USER_NS=y. The reproduced AH crash also requires a matching xfrm AH policy on the outgoing route; a container granted CAP_NET_ADMIN can install that state and policy in its netns. Loopback bypasses xfrm_output, so the trigger uses a real netdev. Reproduced on UML + KASAN: kernel-mode fault at addr 0x0 with memcpy_orig at the crash site. Same shape reproduces inside a rootless Docker container with --cap-add NET_ADMIN on a stock distro kernel. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Suggested-by: Herbert Xu Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/77ec2b5e8111961c2c39883c92e8aa2709039c17.1778614451.git.michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

ipv4: add new arguments to udp_tunnel_dst_lookup()

2026-06-01T15:39:29+00:00

[ Upstream commit 72fc68c6356b663a8763f02d9b0ec773d59a4949 ] We want to make the function more generic so that it can be used by other UDP tunnel implementations such as geneve and vxlan. To do that, add the following arguments: - source and destination UDP port; - ifindex of the output interface, needed by vxlan; - the tos, because in some cases it is not taken from struct ip_tunnel_info (for example, when it's inherited from the inner packet); - the dst cache, because not all tunnel types (e.g. vxlan) want to use the one from struct ip_tunnel_info. With these parameters, the function no longer needs the full struct ip_tunnel_info as argument and we can pass only the relevant part of it (struct ip_tunnel_key). Suggested-by: Guillaume Nault Signed-off-by: Beniamino Galvani Reviewed-by: David Ahern Signed-off-by: David S. Miller Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()") Signed-off-by: Sasha Levin

ipv4: remove "proto" argument from udp_tunnel_dst_lookup()

2026-06-01T15:39:29+00:00

[ Upstream commit 78f3655adcb52412275f282267ee771421731632 ] The function is now UDP-specific, the protocol is always IPPROTO_UDP. Suggested-by: Guillaume Nault Signed-off-by: Beniamino Galvani Reviewed-by: David Ahern Signed-off-by: David S. Miller Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()") Signed-off-by: Sasha Levin

ipv4: rename and move ip_route_output_tunnel()

2026-06-01T15:39:29+00:00

[ Upstream commit bf3fcbf7e7a08015d3b169bad6281b29d45c272d ] At the moment ip_route_output_tunnel() is used only by bareudp. Ideally, other UDP tunnel implementations should use it, but to do so the function needs to accept new parameters that are specific for UDP tunnels, such as the ports. Prepare for these changes by renaming the function to udp_tunnel_dst_lookup() and move it to file net/ipv4/udp_tunnel_core.c. Suggested-by: Guillaume Nault Signed-off-by: Beniamino Galvani Reviewed-by: David Ahern Signed-off-by: David S. Miller Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()") Signed-off-by: Sasha Levin

netfilter: arp_tables: fix IEEE1394 ARP payload parsing

2026-06-01T15:39:27+00:00

[ Upstream commit 1e8e3f449b1e73b73a843257635b9c50f0cc0f0a ] Weiming Shi says: "arp_packet_match() unconditionally parses the ARP payload assuming two hardware addresses are present (source and target). However, IPv4-over-IEEE1394 ARP (RFC 2734) omits the target hardware address field, and arp_hdr_len() already accounts for this by returning a shorter length for ARPHRD_IEEE1394 devices. As a result, on IEEE1394 interfaces arp_packet_match() advances past a nonexistent target hardware address and reads the wrong bytes for both the target device address comparison and the target IP address. This causes arptables rules to match against garbage data, leading to incorrect filtering decisions: packets that should be accepted may be dropped and vice versa. The ARP stack in net/ipv4/arp.c (arp_create and arp_process) already handles this correctly by skipping the target hardware address for ARPHRD_IEEE1394. Apply the same pattern to arp_packet_match()." Mangle the original patch to always return 0 (no match) in case user matches on the target hardware address which is never present in IEEE1394. Note that this returns 0 (no match) for either normal and inverse match because matching in the target hardware address in ARPHRD_IEEE1394 has never been supported by arptables. This is intentional, matching on the target hardware address should never evaluate true for ARPHRD_IEEE1394. Moreover, adjust arpt_mangle to drop the packet too as AI suggests: In arpt_mangle, the logic assumes a standard ARP layout. Because IEEE1394 (FireWire) omits the target hardware address, the linear pointer arithmetic miscalculates the offset for the target IP address. This causes mangling operations to write to the wrong location, leading to packet corruption. To ensure safety, this patch drops packets (NF_DROP) when mangling is requested for these fields on IEEE1394 devices, as the current implementation cannot correctly map the FireWire ARP payload. This omits both mangling target hardware and IP address. Even if IP address mangling should be possible in IEEE1394, this would require to adjust arpt_mangle offset calculation, which has never been supported. Based on patch from Weiming Shi . Fixes: 6752c8db8e0c ("firewire net, ipv4 arp: Extend hardware address and remove driver-level packet inspection.") Reported-by: Xiang Mei Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

tcp: annotate data-races around (tp->write_seq - tp->snd_nxt)

2026-06-01T15:39:23+00:00

[ Upstream commit 3a63b3d160560ef51e43fb4c880a5cde8078053c ] tcp_get_timestamping_opt_stats() intentionally runs lockless, we must add READ_ONCE() annotations to keep KCSAN happy. WRITE_ONCE() annotations are already present. Fixes: e08ab0b377a1 ("tcp: add bytes not sent to SCM_TIMESTAMPING_OPT_STATS") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260416200319.3608680-14-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tcp: annotate data-races around tp->dsack_dups

2026-06-01T15:39:23+00:00

[ Upstream commit a984705ca88b976bf1087978fd98b7f3993da88c ] tcp_get_timestamping_opt_stats() intentionally runs lockless, we must add READ_ONCE() and WRITE_ONCE() annotations to keep KCSAN happy. Fixes: 7e10b6554ff2 ("tcp: add dsack blocks received stats") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260416200319.3608680-10-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tcp: annotate data-races around tp->bytes_retrans

2026-06-01T15:39:23+00:00

[ Upstream commit 5efc7b9f7cbd43401f1af81d3d7f2be00f93390d ] tcp_get_timestamping_opt_stats() intentionally runs lockless, we must add READ_ONCE() and WRITE_ONCE() annotations to keep KCSAN happy. Fixes: fb31c9b9f6c8 ("tcp: add data bytes retransmitted stats") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260416200319.3608680-9-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin