The current scheme for caching the encap socket can lead to reference
leaks when we try to delete the netns.

The reference chain is: xfrm_state -> enacp_sk -> netns

Since the encap socket is a userspace socket, it holds a reference on
the netns. If we delete the espintcp state (through flush or
individual delete) before removing the netns, the reference on the
socket is dropped and the netns is correctly deleted. Otherwise, the
netns may not be reachable anymore (if all processes within the ns
have terminated), so we cannot delete the xfrm state to drop its
reference on the socket.

This patch results in a small (~2% in my tests) performance
regression.

A GC-type mechanism could be added for the socket cache, to clear
references if the state hasn't been used "recently", but it's a lot
more complex than just not caching the socket.

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>

A few error paths are missing a kfree_skb.

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>

Steffen Klassert says:

====================
pull request (net): ipsec 2025-01-27

1) Fix incrementing the upper 32 bit sequence numbers for GSO skbs.
   From Jianbo Liu.

2) Fix an out-of-bounds read on xfrm state lookup.
   From Florian Westphal.

3) Fix secpath handling on packet offload mode.
   From Alexandre Cassen.

4) Fix the usage of skb->sk in the xfrm layer.

5) Don't disable preemption while looking up cache state
   to fix PREEMPT_RT.
   From Sebastian Sewior.

* tag 'ipsec-2025-01-27' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
  xfrm: Don't disable preemption while looking up cache state.
  xfrm: Fix the usage of skb->sk
  xfrm: delete intermediate secpath entry in packet offload mode
  xfrm: state: fix out-of-bounds read during lookup
  xfrm: replay: Fix the update of replay_esn->oseq_hi for GSO
====================

Link: https://patch.msgid.link/20250127060757.3946314-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

xfrm assumed to always have a full socket at skb->sk.
This is not always true, so fix it by converting to a
full socket before it is used.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>

Define `XFRM_MODE_IPTFS` and `IPSEC_MODE_IPTFS` constants, and add these to
switch case and conditionals adjacent with the existing TUNNEL modes.

Signed-off-by: Christian Hopps <chopps@labn.net>
Tested-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Make skb_frag_page() fail in the case where the frag is not backed
by a page, and fix its relevant callers to handle this case.

Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20240910171458.219195-8-almasrymina@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Merge in late fixes to prepare for the 6.11 net-next PR.

Conflicts:
  93c3a96c301f ("net: pse-pd: Do not return EOPNOSUPP if config is null")
  4cddb0f15ea9 ("net: ethtool: pse-pd: Fix possible null-deref")
  30d7b6727724 ("net: ethtool: Add new power limit get and set features")
https://lore.kernel.org/20240715123204.623520bb@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

esp_xmit() is already able to handle UDP encapsulation through the call to
esp_output_head(). However, the ESP header and the outer IP header
are not correct and need to be corrected.

Test: Enabled both dir=in/out IPsec crypto offload, and verified IPv4
      UDP-encapsulated ESP packets on both wifi/cellular network
Signed-off-by: Mike Yu <yumike@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

xmit() functions should consume skb or return error codes in error
paths.
When the configuration "CONFIG_INET_ESPINTCP" is not set, the
implementation of the function "esp_output_tail_tcp" violates this rule.
The function frees the skb and returns the error code.
This change removes the kfree_skb from both functions, for both
esp4 and esp6.
WARN_ON is added because esp_output_tail_tcp() should never be called if
CONFIG_INET_ESPINTCP is not set.

This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.

Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2024-05-03

1) Remove Obsolete UDP_ENCAP_ESPINUDP_NON_IKE Support.
   This was defined by an early version of an IETF draft
   that did not make it to a standard.

2) Introduce direction attribute for xfrm states.
   xfrm states have a direction, a stsate can be used
   either for input or output packet processing.
   Add a direction to xfrm states to make it clear
   for what a xfrm state is used.

* tag 'ipsec-next-2024-05-03' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next:
  xfrm: Restrict SA direction attribute to specific netlink message types
  xfrm: Add dir validation to "in" data path lookup
  xfrm: Add dir validation to "out" data path lookup
  xfrm: Add Direction to the SA in or out
  udpencap: Remove Obsolete UDP_ENCAP_ESPINUDP_NON_IKE Support
====================

Link: https://lore.kernel.org/r/20240503082732.2835810-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>