linux/net/ipv4, branch v6.16

Merge tag 'ipsec-2025-07-23' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

2025-07-24T10:30:40Z

Steffen Klassert says: ==================== pull request (net): ipsec 2025-07-23 1) Premption fixes for xfrm_state_find. From Sabrina Dubroca. 2) Initialize offload path also for SW IPsec GRO. This fixes a performance regression on SW IPsec offload. From Leon Romanovsky. 3) Fix IPsec UDP GRO for IKE packets. From Tobias Brunner, 4) Fix transport header setting for IPcomp after decompressing. From Fernando Fernandez Mancera. 5) Fix use-after-free when xfrmi_changelink tries to change collect_md for a xfrm interface. From Eyal Birger . 6) Delete the special IPcomp x->tunnel state along with the state x to avoid refcount problems. From Sabrina Dubroca. Please pull or let me know if there are problems. * tag 'ipsec-2025-07-23' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec: Revert "xfrm: destroy xfrm_state synchronously on net exit path" xfrm: delete x->tunnel as we delete x xfrm: interface: fix use-after-free after changing collect_md xfrm interface xfrm: ipcomp: adjust transport header after decompressing xfrm: Set transport header to fix UDP GRO handling xfrm: always initialize offload path xfrm: state: use a consistent pcpu_id in xfrm_state_find xfrm: state: initialize state_ptrs earlier in xfrm_state_find ==================== Link: https://patch.msgid.link/20250723075417.3432644-1-steffen.klassert@secunet.com Signed-off-by: Paolo Abeni

net: fix segmentation after TCP/UDP fraglist GRO

2025-07-17T08:01:02Z

Since "net: gro: use cb instead of skb->network_header", the skb network header is no longer set in the GRO path. This breaks fraglist segmentation, which relies on ip_hdr()/tcp_hdr() to check for address/port changes. Fix this regression by selectively setting the network header for merged segment skbs. Fixes: 186b1ea73ad8 ("net: gro: use cb instead of skb->network_header") Signed-off-by: Felix Fietkau Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20250705150622.10699-1-nbd@nbd.name Signed-off-by: Paolo Abeni

tcp: refine sk_rcvbuf increase for ooo packets

2025-07-10T02:24:10Z

When a passive flow has not been accepted yet, it is not wise to increase sk_rcvbuf when receiving ooo packets. A very busy server might tune down tcp_rmem[1] to better control how much memory can be used by sockets waiting in its listeners accept queues. Fixes: 63ad7dfedfae ("tcp: adjust rcvbuf in presence of reorders") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20250707213900.1543248-2-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: Correct signedness in skb remaining space calculation

2025-07-08T14:56:26Z

Syzkaller reported a bug [1] where sk->sk_forward_alloc can overflow. When we send data, if an skb exists at the tail of the write queue, the kernel will attempt to append the new data to that skb. However, the code that checks for available space in the skb is flawed: ''' copy = size_goal - skb->len ''' The types of the variables involved are: ''' copy: ssize_t (s64 on 64-bit systems) size_goal: int skb->len: unsigned int ''' Due to C's type promotion rules, the signed size_goal is converted to an unsigned int to match skb->len before the subtraction. The result is an unsigned int. When this unsigned int result is then assigned to the s64 copy variable, it is zero-extended, preserving its non-negative value. Consequently, copy is always >= 0. Assume we are sending 2GB of data and size_goal has been adjusted to a value smaller than skb->len. The subtraction will result in copy holding a very large positive integer. In the subsequent logic, this large value is used to update sk->sk_forward_alloc, which can easily cause it to overflow. The syzkaller reproducer uses TCP_REPAIR to reliably create this condition. However, this can also occur in real-world scenarios. The tcp_bound_to_half_wnd() function can also reduce size_goal to a small value. This would cause the subsequent tcp_wmem_schedule() to set sk->sk_forward_alloc to a value close to INT_MAX. Further memory allocation requests would then cause sk_forward_alloc to wrap around and become negative. [1]: https://syzkaller.appspot.com/bug?extid=de6565462ab540f50e47 Reported-by: syzbot+de6565462ab540f50e47@syzkaller.appspotmail.com Fixes: 270a1c3de47e ("tcp: Support MSG_SPLICE_PAGES") Signed-off-by: Jiayuan Chen Reviewed-by: Eric Dumazet Reviewed-by: David Howells Link: https://patch.msgid.link/20250707054112.101081-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski

xfrm: delete x->tunnel as we delete x

2025-07-08T11:28:27Z

The ipcomp fallback tunnels currently get deleted (from the various lists and hashtables) as the last user state that needed that fallback is destroyed (not deleted). If a reference to that user state still exists, the fallback state will remain on the hashtables/lists, triggering the WARN in xfrm_state_fini. Because of those remaining references, the fix in commit f75a2804da39 ("xfrm: destroy xfrm_state synchronously on net exit path") is not complete. We recently fixed one such situation in TCP due to defered freeing of skbs (commit 9b6412e6979f ("tcp: drop secpath at the same time as we currently drop dst")). This can also happen due to IP reassembly: skbs with a secpath remain on the reassembly queue until netns destruction. If we can't guarantee that the queues are flushed by the time xfrm_state_fini runs, there may still be references to a (user) xfrm_state, preventing the timely deletion of the corresponding fallback state. Instead of chasing each instance of skbs holding a secpath one by one, this patch fixes the issue directly within xfrm, by deleting the fallback state as soon as the last user state depending on it has been deleted. Destruction will still happen when the final reference is dropped. A separate lockdep class for the fallback state is required since we're going to lock x->tunnel while x is locked. Fixes: 9d4139c76905 ("netns xfrm: per-netns xfrm_state_all list") Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert

net: ipv4: fix stat increase when udp early demux drops the packet

2025-07-02T21:46:44Z

udp_v4_early_demux now returns drop reasons as it either returns 0 or ip_mc_validate_source, which returns itself a drop reason. However its use was not converted in ip_rcv_finish_core and the drop reason is ignored, leading to potentially skipping increasing LINUX_MIB_IPRPFILTER if the drop reason is SKB_DROP_REASON_IP_RPFILTER. This is a fix and we're not converting udp_v4_early_demux to explicitly return a drop reason to ease backports; this can be done as a follow-up. Fixes: d46f827016d8 ("net: ip: make ip_mc_validate_source() return drop reason") Cc: Menglong Dong Reported-by: Sabrina Dubroca Signed-off-by: Antoine Tenart Reviewed-by: Sabrina Dubroca Link: https://patch.msgid.link/20250701074935.144134-1-atenart@kernel.org Signed-off-by: Jakub Kicinski

xfrm: Set transport header to fix UDP GRO handling

2025-07-02T07:19:56Z

The referenced commit replaced a call to __xfrm4|6_udp_encap_rcv() with a custom check for non-ESP markers. But what the called function also did was setting the transport header to the ESP header. The function that follows, esp4|6_gro_receive(), relies on that being set when it calls xfrm_parse_spi(). We have to set the full offset as the skb's head was not moved yet so adding just the UDP header length won't work. Fixes: e3fd05777685 ("xfrm: Fix UDP GRO handling for some corner cases") Signed-off-by: Tobias Brunner Signed-off-by: Steffen Klassert

tcp: fix passive TFO socket having invalid NAPI ID

2025-06-19T01:30:51Z

There is a bug with passive TFO sockets returning an invalid NAPI ID 0 from SO_INCOMING_NAPI_ID. Normally this is not an issue, but zero copy receive relies on a correct NAPI ID to process sockets on the right queue. Fix by adding a sk_mark_napi_id_set(). Fixes: e5907459ce7e ("tcp: Record Rx hash and NAPI ID in tcp_child_process") Signed-off-by: David Wei Reviewed-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250617212102.175711-5-dw@davidwei.uk Signed-off-by: Jakub Kicinski

tcp: fix tcp_packet_delayed() for tcp_is_non_sack_preventing_reopen() behavior

2025-06-18T08:04:34Z

After the following commit from 2024: commit e37ab7373696 ("tcp: fix to allow timestamp undo if no retransmits were sent") ...there was buggy behavior where TCP connections without SACK support could easily see erroneous undo events at the end of fast recovery or RTO recovery episodes. The erroneous undo events could cause those connections to suffer repeated loss recovery episodes and high retransmit rates. The problem was an interaction between the non-SACK behavior on these connections and the undo logic. The problem is that, for non-SACK connections at the end of a loss recovery episode, if snd_una == high_seq, then tcp_is_non_sack_preventing_reopen() holds steady in CA_Recovery or CA_Loss, but clears tp->retrans_stamp to 0. Then upon the next ACK the "tcp: fix to allow timestamp undo if no retransmits were sent" logic saw the tp->retrans_stamp at 0 and erroneously concluded that no data was retransmitted, and erroneously performed an undo of the cwnd reduction, restoring cwnd immediately to the value it had before loss recovery. This caused an immediate burst of traffic and build-up of queues and likely another immediate loss recovery episode. This commit fixes tcp_packet_delayed() to ignore zero retrans_stamp values for non-SACK connections when snd_una is at or above high_seq, because tcp_is_non_sack_preventing_reopen() clears retrans_stamp in this case, so it's not a valid signal that we can undo. Note that the commit named in the Fixes footer restored long-present behavior from roughly 2005-2019, so apparently this bug was present for a while during that era, and this was simply not caught. Fixes: e37ab7373696 ("tcp: fix to allow timestamp undo if no retransmits were sent") Reported-by: Eric Wheeler Closes: https://lore.kernel.org/netdev/64ea9333-e7f9-0df-b0f2-8d566143acab@ewheeler.net/ Signed-off-by: Neal Cardwell Co-developed-by: Yuchung Cheng Signed-off-by: Yuchung Cheng Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

treewide, timers: Rename from_timer() to timer_container_of()

2025-06-08T07:07:37Z

Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com