kernel/linux.git/net/core, branch v7.0.13

net: guard timestamp cmsgs to real error queue skbs

2026-06-19T11:47:52+00:00

[ Upstream commit 1ee90b77b727df903033db873c75caac5c27ec98 ] skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb from sk_error_queue. That assumption is not true for AF_PACKET sockets: outgoing packet taps are also delivered to packet sockets with skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET instead of struct sock_exterr_skb. If such an skb is received with timestamping enabled, the generic timestamp cmsg path can read AF_PACKET control-buffer state as sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop counter overlaps opt_stats. An odd drop count makes the path emit SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear skbs this copies past the linear head and can trigger hardened usercopy or disclose adjacent heap contents. Keep skb_is_err_queue() local to net/socket.c, but make it verify that the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal receive ownership and no longer pass as error-queue skbs, while legitimate sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free ownership. Fixes: 8605330aac5a ("tcp: fix SCM_TIMESTAMPING_OPT_STATS for normal skbs") Signed-off-by: Kyle Zeng Reviewed-by: Kuniyuki Iwashima Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260607021819.49698-1-kylebot@openai.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

netdev: fix double-free in netdev_nl_bind_rx_doit()

2026-06-19T11:47:51+00:00

[ Upstream commit c849de7d8757a7af801fc4a4058f71d481d367f2 ] Sashiko flags that genlmsg_reply() always consumes the skb. The error path calls nlmsg_free(rsp) so we can't jump directly to it. Let's not unbind, just propagate the error to the user. This is the typical way of handling genlmsg_reply() failures. They shouldn't happen unless user does something silly like calling the kernel with an already-full rcvbuf. Reported-by: Sashiko Fixes: 170aafe35cb9 ("netdev: support binding dma-buf to netdevice") Reviewed-by: Bobby Eshleman Acked-by: Daniel Borkmann Reviewed-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: add pskb_may_pull() to skb_gro_receive_list()

2026-06-19T11:47:50+00:00

[ Upstream commit f2bb3434544454099a5b6dec213567267b05d79d ] skb_gro_receive_list() calls skb_pull(skb, skb_gro_offset(skb)) without first ensuring the data is in the linear area via pskb_may_pull(). When the skb arrives via napi_gro_frags(), skb_headlen can be 0 (all data in page fragments) while skb_gro_offset is non-zero (after IP+TCP header parsing). The skb_pull() then decrements skb->len by skb_gro_offset but skb->data_len stays unchanged, hitting BUG_ON(skb->len < skb->data_len) in __skb_pull(). The UDP fraglist GRO path already contains this guard at udp_offload.c:749. Adding it to skb_gro_receive_list() itself provides centralized protection for all callers (TCP, UDP, and any future protocols), and ensures the precondition of skb_pull() is satisfied before it is called. On pskb_may_pull() failure, set NAPI_GRO_CB(skb)->flush = 1 so the skb is not held as a new GRO head and is instead delivered through the normal receive path, matching the UDP handling. Fixes: 8d95dc474f85 ("net: add code for TCP fraglist GRO") Reported-by: HanQuan Reported-by: MingXuan Signed-off-by: HanQuan Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tcp: restrict SO_ATTACH_FILTER to priv users

2026-06-19T11:47:50+00:00

[ Upstream commit 5d39580f68e6ddeedd15e587282207489dfb3da2 ] This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets to users with CAP_NET_ADMIN capability. This blocks potential side-channel attack where an unprivileged application attaches a filter to leak TCP sequence/acknowledgment numbers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: Tamir Shahar Reported-by: Amit Klein Cc: Willem de Bruijn Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Andrii Nakryiko Cc: Martin KaFai Lau Cc: Eduard Zingerman Cc: Kumar Kartikeya Dwivedi Cc: Song Liu Cc: Yonghong Song Cc: Jiri Olsa Cc: John Fastabend Cc: Stanislav Fomichev Acked-by: Daniel Borkmann Reviewed-by: Willem de Bruijn Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: Annotate sk->sk_write_space() for UDP SOCKMAP.

2026-06-19T11:47:44+00:00

[ Upstream commit b748765019fe9e9234660327090fc1a9665cdbdd ] UDP TX skb->destructor() is sock_wfree(), and UDP holds lock_sock() only for UDP_CORK / MSG_MORE sendmsg(). Otherwise, sk->sk_write_space() may be read locklessly while SOCKMAP rewrites sk->sk_write_space(). Let's use WRITE_ONCE() and READ_ONCE() for sk->sk_write_space(). Note that the write side is annotated by commit 2ef2b20cf4e0 ("net: annotate data-races around sk->sk_{data_ready,write_space}"). Fixes: 7b98cd42b049 ("bpf: sockmap: Add UDP support") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jakub Sitnicki Link: https://patch.msgid.link/20260529193941.3897256-1-kuniyu@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

bpf: Free reuseport cBPF prog after RCU grace period.

2026-06-19T11:47:41+00:00

[ Upstream commit 18fc650ccd7fe3376eca89203668cfb8268f60df ] Eulgyu Kim reported the splat below with a repro. [0] The repro sets up a UDP reuseport group with a cBPF prog and replaces it with a new one while another thread is sending a UDP packet to the group. The reuseport prog is freed by sk_reuseport_prog_free(). bpf_prog_put() is called for "e"BPF prog to destruct through multiple stages while cBPF prog is freed immediately by bpf_release_orig_filter() and bpf_prog_free(). If a reuseport prog is detached from the setsockopt() path (reuseport_attach_prog() or reuseport_detach_prog()), sk_reuseport_prog_free() is called without waiting for RCU readers to complete, resulting in various bugs. Let's defer freeing the reuseport cBPF prog after one RCU grace period. Note "e"BPF prog is safe as is unless the fast path starts to touch fields destroyed in bpf_prog_put_deferred() and __bpf_prog_put_noref(). [0]: BUG: KASAN: vmalloc-out-of-bounds in reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596 Read of size 4 at addr ffffc9000051e004 by task slowme/10208 CPU: 6 UID: 1000 PID: 10208 Comm: slowme Not tainted 7.0.0-geb7ac95ff75e #32 PREEMPT(full) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: 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 reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596 udp4_lib_lookup2+0x3bc/0x950 net/ipv4/udp.c:495 __udp4_lib_lookup+0x768/0xe20 net/ipv4/udp.c:723 __udp4_lib_lookup_skb+0x297/0x390 net/ipv4/udp.c:752 __udp4_lib_rcv+0x1312/0x2620 net/ipv4/udp.c:2752 ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6181 [inline] __netif_receive_skb net/core/dev.c:6294 [inline] process_backlog+0xaa4/0x1960 net/core/dev.c:6645 __napi_poll+0xae/0x340 net/core/dev.c:7709 napi_poll net/core/dev.c:7772 [inline] net_rx_action+0x5d7/0xf50 net/core/dev.c:7929 handle_softirqs+0x22b/0x870 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 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+0x1dd7/0x3710 net/core/dev.c:4890 neigh_output include/net/neighbour.h:556 [inline] ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 ip_send_skb+0x45/0xc0 net/ipv4/ip_output.c:1508 udp_send_skb+0xb04/0x1510 net/ipv4/udp.c:1195 udp_sendmsg+0x1a71/0x2350 net/ipv4/udp.c:1485 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x554/0x680 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+0x160/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x415a2d Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6bc31e41e8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f6bc31e4cdc RCX: 0000000000415a2d RDX: 0000000000000001 RSI: 00007f6bc31e421f RDI: 0000000000000003 RBP: 00007f6bc31e4240 R08: 00007f6bc31e4220 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000212 R12: 00007f6bc31e46c0 R13: ffffffffffffffb8 R14: 0000000000000000 R15: 00007ffc9b0d70b0 Fixes: 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF") Reported-by: Eulgyu Kim Reported-by: Taeyang Lee <0wn@theori.io> Signed-off-by: Kuniyuki Iwashima Signed-off-by: Daniel Borkmann Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20260426012647.3233119-1-kuniyu@google.com Signed-off-by: Sasha Levin

net: skbuff: fix missing zerocopy reference in pskb_carve helpers

2026-06-09T10:32:39+00:00

commit 98d0912e9f841e5529a5b89a972805f34cb1c69d upstream. pskb_carve_inside_header() and pskb_carve_inside_nonlinear() both copy the old skb_shared_info header into a new buffer via memcpy(), which includes the destructor_arg pointer (uarg) for MSG_ZEROCOPY skbs. Neither function calls net_zcopy_get() for the new shinfo, creating an unaccounted holder: every skb_shared_info with destructor_arg set will call skb_zcopy_clear() once when freed, but the corresponding net_zcopy_get() was never called for the new copy. Repeated calls drive uarg->refcnt to zero prematurely, freeing ubuf_info_msgzc while TX skbs still hold live destructor_arg pointers. KASAN reports use-after-free on a freed ubuf_info_msgzc: BUG: KASAN: slab-use-after-free in skb_release_data+0x77b/0x810 Read of size 8 at addr ffff88801574d3e8 by task poc/220 Call Trace: skb_release_data+0x77b/0x810 kfree_skb_list_reason+0x13e/0x610 skb_release_data+0x4cd/0x810 sk_skb_reason_drop+0xf3/0x340 skb_queue_purge_reason+0x282/0x440 rds_tcp_inc_free+0x1e/0x30 rds_recvmsg+0x354/0x1780 __sys_recvmsg+0xdf/0x180 Allocated by task 219: msg_zerocopy_realloc+0x157/0x7b0 tcp_sendmsg_locked+0x2892/0x3ba0 Freed by task 219: ip_recv_error+0x74a/0xb10 tcp_recvmsg+0x475/0x530 The skb consuming the late access still referenced the same uarg via shinfo->destructor_arg copied by pskb_carve_inside_nonlinear() without a refcount bump. This has been verified to be reliably exploitable: a working proof-of-concept achieves full root privilege escalation from an unprivileged local user on a default kernel configuration. The fix follows the pattern of pskb_expand_head() which has the same memcpy/cloned structure. For pskb_carve_inside_header(), net_zcopy_get() is placed after skb_orphan_frags() succeeds, so the orphan error path needs no cleanup. For pskb_carve_inside_nonlinear(), net_zcopy_get() is placed after all failure points and just before skb_release_data(), so no error path needs cleanup at all -- matching pskb_expand_head() more closely and avoiding the need for a balancing net_zcopy_put(). Fixes: 6fa01ccd8830 ("skbuff: Add pskb_extract() helper function") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-sonnet-4-6 Signed-off-by: Minh Nguyen Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260526041240.329462-1-minhnguyen.080505@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

bpf: sockmap: fix tail fragment offset in bpf_msg_push_data

2026-06-09T10:32:38+00:00

commit f72eed9b84fb771019a955908132410a9ba9ea3f upstream. When bpf_msg_push_data() inserts data in the middle of a scatterlist entry, it splits the original entry into a left fragment and a right fragment. The right fragment offset is page-local, but the code advances it with `start`, which is the message-global insertion point. For inserts into a non-first SG entry, this over-advances the offset and leaves the split layout inconsistent. Advance the right fragment offset by the fragment-local delta, `start - offset`, which matches the length removed from the front of the original entry. Fixes: 6fff607e2f14 ("bpf: sk_msg program helper bpf_msg_push_data") Cc: stable@kernel.org Reported-by: Yuan Tan Reported-by: Zhengchuan Liang Reported-by: Xin Liu Signed-off-by: Yuqi Xu Signed-off-by: Ren Wei Link: https://patch.msgid.link/8b129d10566aa3eb43f61a8f9757bcf51707d324.1779636774.git.xuyq21@lenovo.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: skbuff: fix pskb_carve leaking zcopy pages

2026-06-09T10:32:29+00:00

[ Upstream commit ff6e798c2eac3ebd0501ad7e796f583fab928de8 ] When SKBFL_MANAGED_FRAG_REFS is set, frag pages are not refcounted but their lifetime is controlled by the attached ubuf_info. To make a copy of the skb_shared_info, we either should clear the flag and reference the frags, or keep the flag and have frags unreferenced. pskb_carve_inside_header() and pskb_carve_inside_nonlinear() don't follow the rule and thus can leak page references. Let's clear SKBFL_MANAGED_FRAG_REFS from the original skb to fix it. It's the simplest way to address it, but there are more performant ways to do that if it ever becomes a problem. Link: https://lore.kernel.org/all/20260523085809.26331-1-nvminh232@clc.fitus.edu.vn/ Fixes: 753f1ca4e1e50 ("net: introduce managed frags infrastructure") Reported-by: Minh Nguyen Reported-by: Willem de Bruijn Signed-off-by: Pavel Begunkov Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/1e2086aa69217d7f9c8da3d38f5be7160f1b4cd1.1779993185.git.asml.silence@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: Avoid checksumming unreadable skb tail on trim

2026-06-09T10:32:23+00:00

[ Upstream commit 2e357f002c61fd76fd8f12468744a06a5ec48eaa ] pskb_trim_rcsum_slow() keeps CHECKSUM_COMPLETE valid by subtracting the checksum of the bytes removed from the skb tail. That assumes the removed bytes can be read. io_uring zcrx skbs may contain unreadable net_iov frags. With fbnic header/data split, small TCP/IPv4 packets can carry Ethernet padding in such a frag. ip_rcv_core() trims the skb to iph->tot_len before TCP sees it, and the CHECKSUM_COMPLETE adjustment then calls skb_checksum() on the padding. This is exposed by IPv4 because small TCP/IPv4 frames can be shorter than the Ethernet minimum payload. TCP/IPv6 frames are large enough in the normal zcrx path, so they do not hit the same padding trim. Keep the existing checksum adjustment for readable skbs. If the remaining packet is fully linear, drop CHECKSUM_COMPLETE and let the stack validate the packet after trimming. If unreadable payload would remain, fail the trim; the checksum cannot be adjusted without reading the trimmed tail. Also clear skb->unreadable when trimming removes all frags. Fixes: 65249feb6b3d ("net: add support for skbs with unreadable frags") Signed-off-by: Björn Töpel Reviewed-by: Breno Leitao Link: https://patch.msgid.link/20260522120643.242974-1-bjorn@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin