commit cecd39af8a1ab81373fd9fa765b2f7ab73becaad Author: Greg Kroah-Hartman Date: Thu Oct 15 14:16:28 2026 +0200 Linux 6.6.159 Signed-off-by: Greg Kroah-Hartman commit 742f73df544e03744f2981c467d6542fe8172a2a Author: Eric Dumazet Date: Thu Oct 1 22:12:53 2026 +0000 ipv4: free inet_opt and ireq_opt after an RCU grace period commit e3f33b0a1d89d738e2b913dab519226eaf76e15b upstream. tcp_v4_syn_recv_sock() transfers ownership of ireq->ireq_opt to the child socket (newinet->inet_opt) without copying it. Another cpu can concurrently process a retransmitted SYN for the same request socket, and send a SYNACK from tcp_check_req(). tcp_v4_send_synack() and inet_csk_route_req() read ireq->ireq_opt under rcu_read_lock() only, and ip_build_and_send_pkt() and ip_options_build() then read opt->optlen twice. Note that the SYNACK timer itself is not an issue: it holds a reference on its request socket, and inet_csk_reqsk_queue_drop() calls timer_delete_sync() before the child can be freed. Since commit 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table"), request sockets are processed without holding the listener lock, so nothing prevents the child socket from being freed while the SYNACK is still being built. TCP child sockets do not have SOCK_RCU_FREE, and inet_sock_destruct() frees inet_opt with a plain kfree(), leading to a use-after-free in ip_options_build(). A similar issue exists with request socket migration (net.ipv4.tcp_migrate_req=1, or a BPF_SK_REUSEPORT_SELECT_OR_MIGRATE program). reqsk_timer_handler() clones the request socket with inet_reqsk_clone(), so that the old request socket and its clone share the same ireq_opt, then reqsk_migrate_reset() clears the pointer in the old one. Another cpu holding a reference on the old request socket can still be using these options (sending a SYNACK, or creating a child in tcp_v4_syn_recv_sock()) when the clone is freed, and tcp_v4_reqsk_destructor() also uses a plain kfree(). Readers already use RCU, and other paths replacing inet_opt (do_ip_setsockopt(), cipso_v4_sock_setattr()...) already use kfree_rcu(). Use kfree_rcu() in inet_sock_destruct() and tcp_v4_reqsk_destructor() as well. IPv6 is not affected by the first issue, because tcp_v6_syn_recv_sock() duplicates the options. tcp_v6_reqsk_destructor() has the same migration issue with ipv6_opt, which is only set by CALIPSO. This will be addressed in a separate patch. Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") Fixes: c905dee62232 ("tcp: Migrate TCP_NEW_SYN_RECV requests at retransmitting SYN+ACKs.") Reported-by: Xinyang Ge Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20261001221253.2964024-1-edumazet@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman commit a65f69e0f38ffbed1b128029e09097436416dc8b Author: Michael S. Tsirkin Date: Wed Oct 7 18:42:49 2026 -0400 ipv4: validate checksum_start before completing checksum commit 6785011f8b16abf40b1e9d8b2e332232b3e68822 upstream. If a packet with bad checksum metadata gets into the ipv4 stack, skb_checksum_help can corrupt the network header and cause a bunch of mischief. This was discovered and reported by Paulos, and has been reporoduced by others independently since. We really shouldn't allow such packets in, but as a defence in depth measure, let's also check before we complete the checksum. A more complete validation at input is forthcoming, but needs more work. Cc: stable@vger.kernel.org Fixes: f43798c27684 ("tun: Allow GSO using virtio_net_hdr") Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.") Reported-by: Paulos Yibelo Closes: https://lore.kernel.org/netdev/20260922030310.8684-2-habte.yibelo@gmail.com/ Signed-off-by: Michael S. Tsirkin Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/0a012b4923e189c4c593ef4f471e5ff0edbe9030.1791412497.git.mst@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman commit 33aa3b7f4afbd3da85401c914b5e47ef91a86fb0 Author: Antonio Ojea Date: Thu Jun 27 13:27:10 2024 +0200 netfilter: nfnetlink_queue: unbreak SCTP traffic commit 26a77d02891ab62172085a4f94af9b3c90aed387 upstream. when packet is enqueued with nfqueue and GSO is enabled, checksum calculation has to take into account the protocol, as SCTP uses a 32 bits CRC checksum. Enter skb_gso_segment() path in case of SCTP GSO packets because skb_zerocopy() does not support for GSO_BY_FRAGS. Joint work with Pablo. Signed-off-by: Antonio Ojea Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman