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2025-09-19psp: Fix typo in kdoc for struct psp_dev_caps.assoc_drv_spc.Kuniyuki Iwashima
assoc_drv_spc is the size of psp_assoc.drv_data[]. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250918192539.1587586-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-19psp: don't use flags for checking sk_stateDaniel Zahka
Using flags to check sk_state only makes sense to check for a subset of states in parallel e.g. sk_fullsock(). We are not doing that here. Compare for individual states directly. Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Link: https://patch.msgid.link/20250918155205.2197603-4-daniel.zahka@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-19psp: fix preemptive inet_twsk() cast in psp_sk_get_assoc_rcu()Daniel Zahka
It is weird to cast to a timewait_sock before checking sk_state, even if the use is after such a check. Remove the tw local variable, and use inet_twsk() directly in the timewait branch. Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Link: https://patch.msgid.link/20250918155205.2197603-3-daniel.zahka@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-19psp: make struct sock argument const in psp_sk_get_assoc_rcu()Daniel Zahka
This function does not need a mutable reference to its argument. Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Link: https://patch.msgid.link/20250918155205.2197603-2-daniel.zahka@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-18psp: provide decapsulation and receive helper for driversRaed Salem
Create psp_dev_rcv(), which drivers can call to psp decapsulate and attach a psp_skb_ext to an skb. psp_dev_rcv() only supports what the PSP architecture specification refers to as "transport mode" packets, where the L3 header is either IPv6 or IPv4. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Raed Salem <raeds@nvidia.com> Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com> Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-18-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18psp: provide encapsulation helper for driversRaed Salem
Create a new function psp_encapsulate(), which takes a TCP packet and PSP encapsulates it according to the "Transport Mode Packet Format" section of the PSP Architecture Specification. psp_encapsulate() does not push a PSP trailer onto the skb. Both IPv6 and IPv4 are supported. Virtualization cookie is not included. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Raed Salem <raeds@nvidia.com> Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com> Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-14-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18psp: track generations of device keyJakub Kicinski
There is a (somewhat theoretical in absence of multi-host support) possibility that another entity will rotate the key and we won't know. This may lead to accepting packets with matching SPI but which used different crypto keys than we expected. The PSP Architecture specification mentions that an implementation should track device key generation when device keys are managed by the NIC. Some PSP implementations may opt to include this key generation state in decryption metadata each time a device key is used to decrypt a packet. If that is the case, that key generation counter can also be used when policy checking a decrypted skb against a psp_assoc. This is an optional feature that is not explicitly part of the PSP spec, but can provide additional security in the case where an attacker may have the ability to force key rotations faster than rekeying can occur. Since we're tracking "key generations" more explicitly now, maintain different lists for associations from different generations. This way we can catch stale associations (the user space should listen to rotation notifications and change the keys). Drivers can "opt out" of generation tracking by setting the generation value to 0. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-11-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18net: psp: update the TCP MSS to reflect PSP packet overheadJakub Kicinski
PSP eats 40B of header space. Adjust MSS appropriately. We can either modify tcp_mtu_to_mss() / tcp_mss_to_mtu() or reuse icsk_ext_hdr_len. The former option is more TCP specific and has runtime overhead. The latter is a bit of a hack as PSP is not an ext_hdr. If one squints hard enough, UDP encap is just a more practical version of IPv6 exthdr, so go with the latter. Happy to change. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-10-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18net: psp: add socket security association codeJakub Kicinski
Add the ability to install PSP Rx and Tx crypto keys on TCP connections. Netlink ops are provided for both operations. Rx side combines allocating a new Rx key and installing it on the socket. Theoretically these are separate actions, but in practice they will always be used one after the other. We can add distinct "alloc" and "install" ops later. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-9-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18psp: add op for rotation of device keyJakub Kicinski
Rotating the device key is a key part of the PSP protocol design. Some external daemon needs to do it once a day, or so. Add a netlink op to perform this operation. Add a notification group for informing users that key has been rotated and they should rekey (next rotation will cut them off). Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-6-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: add datapath logic for PSP with inline key exchangeJakub Kicinski
Add validation points and state propagation to support PSP key exchange inline, on TCP connections. The expectation is that application will use some well established mechanism like TLS handshake to establish a secure channel over the connection and if both endpoints are PSP-capable - exchange and install PSP keys. Because the connection can existing in PSP-unsecured and PSP-secured state we need to make sure that there are no race conditions or retransmission leaks. On Tx - mark packets with the skb->decrypted bit when PSP key is at the enqueue time. Drivers should only encrypt packets with this bit set. This prevents retransmissions getting encrypted when original transmission was not. Similarly to TLS, we'll use sk->sk_validate_xmit_skb to make sure PSP skbs can't "escape" via a PSP-unaware device without being encrypted. On Rx - validation is done under socket lock. This moves the validation point later than xfrm, for example. Please see the documentation patch for more details on the flow of securing a connection, but for the purpose of this patch what's important is that we want to enforce the invariant that once connection is secured any skb in the receive queue has been encrypted with PSP. Add GRO and coalescing checks to prevent PSP authenticated data from being combined with cleartext data, or data with non-matching PSP state. On Rx, check skb's with psp_skb_coalesce_diff() at points before psp_sk_rx_policy_check(). After skb's are policy checked and on the socket receive queue, skb_cmp_decrypted() is sufficient for checking for coalescable PSP state. On Tx, tcp_write_collapse_fence() should be called when transitioning a socket into PSP Tx state to prevent data sent as cleartext from being coalesced with PSP encapsulated data. This change only adds the validation points, for ease of review. Subsequent change will add the ability to install keys, and flesh the enforcement logic out Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-5-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18net: modify core data structures for PSP datapath supportJakub Kicinski
Add pointers to psp data structures to core networking structs, and an SKB extension to carry the PSP information from the drivers to the socket layer. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-4-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18psp: base PSP device supportJakub Kicinski
Add a netlink family for PSP and allow drivers to register support. The "PSP device" is its own object. This allows us to perform more flexible reference counting / lifetime control than if PSP information was part of net_device. In the future we should also be able to "delegate" PSP access to software devices, such as *vlan, veth or netkit more easily. Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250917000954.859376-3-daniel.zahka@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>