Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/* Kerberos-based RxRPC security
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */
 
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
#include <crypto/skcipher.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/scatterlist.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <keys/rxrpc-type.h>
#include "ar-internal.h"
 
#define RXKAD_VERSION			2
#define MAXKRB5TICKETLEN		1024
#define RXKAD_TKT_TYPE_KERBEROS_V5	256
#define ANAME_SZ			40	/* size of authentication name */
#define INST_SZ				40	/* size of principal's instance */
#define REALM_SZ			40	/* size of principal's auth domain */
#define SNAME_SZ			40	/* size of service name */
 
struct rxkad_level1_hdr {
<------>__be32	data_size;	/* true data size (excluding padding) */
};
 
struct rxkad_level2_hdr {
<------>__be32	data_size;	/* true data size (excluding padding) */
<------>__be32	checksum;	/* decrypted data checksum */
};
 
/*
 * this holds a pinned cipher so that keventd doesn't get called by the cipher
 * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE
 * packets
 */
static struct crypto_sync_skcipher *rxkad_ci;
static struct skcipher_request *rxkad_ci_req;
static DEFINE_MUTEX(rxkad_ci_mutex);
 
/*
 * initialise connection security
 */
static int rxkad_init_connection_security(struct rxrpc_connection *conn)
{
<------>struct crypto_sync_skcipher *ci;
<------>struct rxrpc_key_token *token;
<------>int ret;
 
<------>_enter("{%d},{%x}", conn->debug_id, key_serial(conn->params.key));
 
<------>token = conn->params.key->payload.data[0];
<------>conn->security_ix = token->security_index;
 
<------>ci = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
<------>if (IS_ERR(ci)) {
<------><------>_debug("no cipher");
<------><------>ret = PTR_ERR(ci);
<------><------>goto error;
<------>}
 
<------>if (crypto_sync_skcipher_setkey(ci, token->kad->session_key,
<------><------><------><------>   sizeof(token->kad->session_key)) < 0)
<------><------>BUG();
 
<------>switch (conn->params.security_level) {
<------>case RXRPC_SECURITY_PLAIN:
<------><------>break;
<------>case RXRPC_SECURITY_AUTH:
<------><------>conn->size_align = 8;
<------><------>conn->security_size = sizeof(struct rxkad_level1_hdr);
<------><------>break;
<------>case RXRPC_SECURITY_ENCRYPT:
<------><------>conn->size_align = 8;
<------><------>conn->security_size = sizeof(struct rxkad_level2_hdr);
<------><------>break;
<------>default:
<------><------>ret = -EKEYREJECTED;
<------><------>goto error;
<------>}
 
<------>conn->cipher = ci;
<------>ret = 0;
error:
<------>_leave(" = %d", ret);
<------>return ret;
}
 
/*
 * prime the encryption state with the invariant parts of a connection's
 * description
 */
static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
{
<------>struct skcipher_request *req;
<------>struct rxrpc_key_token *token;
<------>struct scatterlist sg;
<------>struct rxrpc_crypt iv;
<------>__be32 *tmpbuf;
<------>size_t tmpsize = 4 * sizeof(__be32);
 
<------>_enter("");
 
<------>if (!conn->params.key)
<------><------>return 0;
 
<------>tmpbuf = kmalloc(tmpsize, GFP_KERNEL);
<------>if (!tmpbuf)
<------><------>return -ENOMEM;
 
<------>req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
<------>if (!req) {
<------><------>kfree(tmpbuf);
<------><------>return -ENOMEM;
<------>}
 
<------>token = conn->params.key->payload.data[0];
<------>memcpy(&iv, token->kad->session_key, sizeof(iv));
 
<------>tmpbuf[0] = htonl(conn->proto.epoch);
<------>tmpbuf[1] = htonl(conn->proto.cid);
<------>tmpbuf[2] = 0;
<------>tmpbuf[3] = htonl(conn->security_ix);
 
<------>sg_init_one(&sg, tmpbuf, tmpsize);
<------>skcipher_request_set_sync_tfm(req, conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, &sg, &sg, tmpsize, iv.x);
<------>crypto_skcipher_encrypt(req);
<------>skcipher_request_free(req);
 
<------>memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
<------>kfree(tmpbuf);
<------>_leave(" = 0");
<------>return 0;
}
 
/*
 * Allocate and prepare the crypto request on a call.  For any particular call,
 * this is called serially for the packets, so no lock should be necessary.
 */
static struct skcipher_request *rxkad_get_call_crypto(struct rxrpc_call *call)
{
<------>struct crypto_skcipher *tfm = &call->conn->cipher->base;
<------>struct skcipher_request	*cipher_req = call->cipher_req;
 
<------>if (!cipher_req) {
<------><------>cipher_req = skcipher_request_alloc(tfm, GFP_NOFS);
<------><------>if (!cipher_req)
<------><------><------>return NULL;
<------><------>call->cipher_req = cipher_req;
<------>}
 
<------>return cipher_req;
}
 
/*
 * Clean up the crypto on a call.
 */
static void rxkad_free_call_crypto(struct rxrpc_call *call)
{
<------>if (call->cipher_req)
<------><------>skcipher_request_free(call->cipher_req);
<------>call->cipher_req = NULL;
}
 
/*
 * partially encrypt a packet (level 1 security)
 */
static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
<------><------><------><------>    struct sk_buff *skb,
<------><------><------><------>    u32 data_size,
<------><------><------><------>    void *sechdr,
<------><------><------><------>    struct skcipher_request *req)
{
<------>struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
<------>struct rxkad_level1_hdr hdr;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist sg;
<------>u16 check;
 
<------>_enter("");
 
<------>check = sp->hdr.seq ^ call->call_id;
<------>data_size |= (u32)check << 16;
 
<------>hdr.data_size = htonl(data_size);
<------>memcpy(sechdr, &hdr, sizeof(hdr));
 
<------>/* start the encryption afresh */
<------>memset(&iv, 0, sizeof(iv));
 
<------>sg_init_one(&sg, sechdr, 8);
<------>skcipher_request_set_sync_tfm(req, call->conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
<------>crypto_skcipher_encrypt(req);
<------>skcipher_request_zero(req);
 
<------>_leave(" = 0");
<------>return 0;
}
 
/*
 * wholly encrypt a packet (level 2 security)
 */
static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
<------><------><------><------>       struct sk_buff *skb,
<------><------><------><------>       u32 data_size,
<------><------><------><------>       void *sechdr,
<------><------><------><------>       struct skcipher_request *req)
{
<------>const struct rxrpc_key_token *token;
<------>struct rxkad_level2_hdr rxkhdr;
<------>struct rxrpc_skb_priv *sp;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist sg[16];
<------>unsigned int len;
<------>u16 check;
<------>int err;
 
<------>sp = rxrpc_skb(skb);
 
<------>_enter("");
 
<------>check = sp->hdr.seq ^ call->call_id;
 
<------>rxkhdr.data_size = htonl(data_size | (u32)check << 16);
<------>rxkhdr.checksum = 0;
<------>memcpy(sechdr, &rxkhdr, sizeof(rxkhdr));
 
<------>/* encrypt from the session key */
<------>token = call->conn->params.key->payload.data[0];
<------>memcpy(&iv, token->kad->session_key, sizeof(iv));
 
<------>sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
<------>skcipher_request_set_sync_tfm(req, call->conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, &sg[0], &sg[0], sizeof(rxkhdr), iv.x);
<------>crypto_skcipher_encrypt(req);
 
<------>/* we want to encrypt the skbuff in-place */
<------>err = -EMSGSIZE;
<------>if (skb_shinfo(skb)->nr_frags > 16)
<------><------>goto out;
 
<------>len = data_size + call->conn->size_align - 1;
<------>len &= ~(call->conn->size_align - 1);
 
<------>sg_init_table(sg, ARRAY_SIZE(sg));
<------>err = skb_to_sgvec(skb, sg, 0, len);
<------>if (unlikely(err < 0))
<------><------>goto out;
<------>skcipher_request_set_crypt(req, sg, sg, len, iv.x);
<------>crypto_skcipher_encrypt(req);
 
<------>_leave(" = 0");
<------>err = 0;
 
out:
<------>skcipher_request_zero(req);
<------>return err;
}
 
/*
 * checksum an RxRPC packet header
 */
static int rxkad_secure_packet(struct rxrpc_call *call,
<------><------><------>       struct sk_buff *skb,
<------><------><------>       size_t data_size,
<------><------><------>       void *sechdr)
{
<------>struct rxrpc_skb_priv *sp;
<------>struct skcipher_request	*req;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist sg;
<------>u32 x, y;
<------>int ret;
 
<------>sp = rxrpc_skb(skb);
 
<------>_enter("{%d{%x}},{#%u},%zu,",
<------>       call->debug_id, key_serial(call->conn->params.key),
<------>       sp->hdr.seq, data_size);
 
<------>if (!call->conn->cipher)
<------><------>return 0;
 
<------>ret = key_validate(call->conn->params.key);
<------>if (ret < 0)
<------><------>return ret;
 
<------>req = rxkad_get_call_crypto(call);
<------>if (!req)
<------><------>return -ENOMEM;
 
<------>/* continue encrypting from where we left off */
<------>memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
 
<------>/* calculate the security checksum */
<------>x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
<------>x |= sp->hdr.seq & 0x3fffffff;
<------>call->crypto_buf[0] = htonl(call->call_id);
<------>call->crypto_buf[1] = htonl(x);
 
<------>sg_init_one(&sg, call->crypto_buf, 8);
<------>skcipher_request_set_sync_tfm(req, call->conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
<------>crypto_skcipher_encrypt(req);
<------>skcipher_request_zero(req);
 
<------>y = ntohl(call->crypto_buf[1]);
<------>y = (y >> 16) & 0xffff;
<------>if (y == 0)
<------><------>y = 1; /* zero checksums are not permitted */
<------>sp->hdr.cksum = y;
 
<------>switch (call->conn->params.security_level) {
<------>case RXRPC_SECURITY_PLAIN:
<------><------>ret = 0;
<------><------>break;
<------>case RXRPC_SECURITY_AUTH:
<------><------>ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr,
<------><------><------><------><------>       req);
<------><------>break;
<------>case RXRPC_SECURITY_ENCRYPT:
<------><------>ret = rxkad_secure_packet_encrypt(call, skb, data_size,
<------><------><------><------><------><------>  sechdr, req);
<------><------>break;
<------>default:
<------><------>ret = -EPERM;
<------><------>break;
<------>}
 
<------>_leave(" = %d [set %hx]", ret, y);
<------>return ret;
}
 
/*
 * decrypt partial encryption on a packet (level 1 security)
 */
static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
<------><------><------><------> unsigned int offset, unsigned int len,
<------><------><------><------> rxrpc_seq_t seq,
<------><------><------><------> struct skcipher_request *req)
{
<------>struct rxkad_level1_hdr sechdr;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist sg[16];
<------>bool aborted;
<------>u32 data_size, buf;
<------>u16 check;
<------>int ret;
 
<------>_enter("");
 
<------>if (len < 8) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_hdr", "V1H",
<------><------><------><------><------>   RXKADSEALEDINCON);
<------><------>goto protocol_error;
<------>}
 
<------>/* Decrypt the skbuff in-place.  TODO: We really want to decrypt
<------> * directly into the target buffer.
<------> */
<------>sg_init_table(sg, ARRAY_SIZE(sg));
<------>ret = skb_to_sgvec(skb, sg, offset, 8);
<------>if (unlikely(ret < 0))
<------><------>return ret;
 
<------>/* start the decryption afresh */
<------>memset(&iv, 0, sizeof(iv));
 
<------>skcipher_request_set_sync_tfm(req, call->conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, sg, sg, 8, iv.x);
<------>crypto_skcipher_decrypt(req);
<------>skcipher_request_zero(req);
 
<------>/* Extract the decrypted packet length */
<------>if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_len", "XV1",
<------><------><------><------><------>     RXKADDATALEN);
<------><------>goto protocol_error;
<------>}
<------>offset += sizeof(sechdr);
<------>len -= sizeof(sechdr);
 
<------>buf = ntohl(sechdr.data_size);
<------>data_size = buf & 0xffff;
 
<------>check = buf >> 16;
<------>check ^= seq ^ call->call_id;
<------>check &= 0xffff;
<------>if (check != 0) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_check", "V1C",
<------><------><------><------><------>     RXKADSEALEDINCON);
<------><------>goto protocol_error;
<------>}
 
<------>if (data_size > len) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_1_datalen", "V1L",
<------><------><------><------><------>     RXKADDATALEN);
<------><------>goto protocol_error;
<------>}
 
<------>_leave(" = 0 [dlen=%x]", data_size);
<------>return 0;
 
protocol_error:
<------>if (aborted)
<------><------>rxrpc_send_abort_packet(call);
<------>return -EPROTO;
}
 
/*
 * wholly decrypt a packet (level 2 security)
 */
static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
<------><------><------><------> unsigned int offset, unsigned int len,
<------><------><------><------> rxrpc_seq_t seq,
<------><------><------><------> struct skcipher_request *req)
{
<------>const struct rxrpc_key_token *token;
<------>struct rxkad_level2_hdr sechdr;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist _sg[4], *sg;
<------>bool aborted;
<------>u32 data_size, buf;
<------>u16 check;
<------>int nsg, ret;
 
<------>_enter(",{%d}", skb->len);
 
<------>if (len < 8) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_hdr", "V2H",
<------><------><------><------><------>     RXKADSEALEDINCON);
<------><------>goto protocol_error;
<------>}
 
<------>/* Decrypt the skbuff in-place.  TODO: We really want to decrypt
<------> * directly into the target buffer.
<------> */
<------>sg = _sg;
<------>nsg = skb_shinfo(skb)->nr_frags;
<------>if (nsg <= 4) {
<------><------>nsg = 4;
<------>} else {
<------><------>sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO);
<------><------>if (!sg)
<------><------><------>goto nomem;
<------>}
 
<------>sg_init_table(sg, nsg);
<------>ret = skb_to_sgvec(skb, sg, offset, len);
<------>if (unlikely(ret < 0)) {
<------><------>if (sg != _sg)
<------><------><------>kfree(sg);
<------><------>return ret;
<------>}
 
<------>/* decrypt from the session key */
<------>token = call->conn->params.key->payload.data[0];
<------>memcpy(&iv, token->kad->session_key, sizeof(iv));
 
<------>skcipher_request_set_sync_tfm(req, call->conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, sg, sg, len, iv.x);
<------>crypto_skcipher_decrypt(req);
<------>skcipher_request_zero(req);
<------>if (sg != _sg)
<------><------>kfree(sg);
 
<------>/* Extract the decrypted packet length */
<------>if (skb_copy_bits(skb, offset, &sechdr, sizeof(sechdr)) < 0) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_len", "XV2",
<------><------><------><------><------>     RXKADDATALEN);
<------><------>goto protocol_error;
<------>}
<------>offset += sizeof(sechdr);
<------>len -= sizeof(sechdr);
 
<------>buf = ntohl(sechdr.data_size);
<------>data_size = buf & 0xffff;
 
<------>check = buf >> 16;
<------>check ^= seq ^ call->call_id;
<------>check &= 0xffff;
<------>if (check != 0) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_check", "V2C",
<------><------><------><------><------>     RXKADSEALEDINCON);
<------><------>goto protocol_error;
<------>}
 
<------>if (data_size > len) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_2_datalen", "V2L",
<------><------><------><------><------>     RXKADDATALEN);
<------><------>goto protocol_error;
<------>}
 
<------>_leave(" = 0 [dlen=%x]", data_size);
<------>return 0;
 
protocol_error:
<------>if (aborted)
<------><------>rxrpc_send_abort_packet(call);
<------>return -EPROTO;
 
nomem:
<------>_leave(" = -ENOMEM");
<------>return -ENOMEM;
}
 
/*
 * Verify the security on a received packet or subpacket (if part of a
 * jumbo packet).
 */
static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
<------><------><------>       unsigned int offset, unsigned int len,
<------><------><------>       rxrpc_seq_t seq, u16 expected_cksum)
{
<------>struct skcipher_request	*req;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist sg;
<------>bool aborted;
<------>u16 cksum;
<------>u32 x, y;
 
<------>_enter("{%d{%x}},{#%u}",
<------>       call->debug_id, key_serial(call->conn->params.key), seq);
 
<------>if (!call->conn->cipher)
<------><------>return 0;
 
<------>req = rxkad_get_call_crypto(call);
<------>if (!req)
<------><------>return -ENOMEM;
 
<------>/* continue encrypting from where we left off */
<------>memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
 
<------>/* validate the security checksum */
<------>x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
<------>x |= seq & 0x3fffffff;
<------>call->crypto_buf[0] = htonl(call->call_id);
<------>call->crypto_buf[1] = htonl(x);
 
<------>sg_init_one(&sg, call->crypto_buf, 8);
<------>skcipher_request_set_sync_tfm(req, call->conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, &sg, &sg, 8, iv.x);
<------>crypto_skcipher_encrypt(req);
<------>skcipher_request_zero(req);
 
<------>y = ntohl(call->crypto_buf[1]);
<------>cksum = (y >> 16) & 0xffff;
<------>if (cksum == 0)
<------><------>cksum = 1; /* zero checksums are not permitted */
 
<------>if (cksum != expected_cksum) {
<------><------>aborted = rxrpc_abort_eproto(call, skb, "rxkad_csum", "VCK",
<------><------><------><------><------>     RXKADSEALEDINCON);
<------><------>goto protocol_error;
<------>}
 
<------>switch (call->conn->params.security_level) {
<------>case RXRPC_SECURITY_PLAIN:
<------><------>return 0;
<------>case RXRPC_SECURITY_AUTH:
<------><------>return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
<------>case RXRPC_SECURITY_ENCRYPT:
<------><------>return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
<------>default:
<------><------>return -ENOANO;
<------>}
 
protocol_error:
<------>if (aborted)
<------><------>rxrpc_send_abort_packet(call);
<------>return -EPROTO;
}
 
/*
 * Locate the data contained in a packet that was partially encrypted.
 */
static void rxkad_locate_data_1(struct rxrpc_call *call, struct sk_buff *skb,
<------><------><------><------>unsigned int *_offset, unsigned int *_len)
{
<------>struct rxkad_level1_hdr sechdr;
 
<------>if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
<------><------>BUG();
<------>*_offset += sizeof(sechdr);
<------>*_len = ntohl(sechdr.data_size) & 0xffff;
}
 
/*
 * Locate the data contained in a packet that was completely encrypted.
 */
static void rxkad_locate_data_2(struct rxrpc_call *call, struct sk_buff *skb,
<------><------><------><------>unsigned int *_offset, unsigned int *_len)
{
<------>struct rxkad_level2_hdr sechdr;
 
<------>if (skb_copy_bits(skb, *_offset, &sechdr, sizeof(sechdr)) < 0)
<------><------>BUG();
<------>*_offset += sizeof(sechdr);
<------>*_len = ntohl(sechdr.data_size) & 0xffff;
}
 
/*
 * Locate the data contained in an already decrypted packet.
 */
static void rxkad_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
<------><------><------>      unsigned int *_offset, unsigned int *_len)
{
<------>switch (call->conn->params.security_level) {
<------>case RXRPC_SECURITY_AUTH:
<------><------>rxkad_locate_data_1(call, skb, _offset, _len);
<------><------>return;
<------>case RXRPC_SECURITY_ENCRYPT:
<------><------>rxkad_locate_data_2(call, skb, _offset, _len);
<------><------>return;
<------>default:
<------><------>return;
<------>}
}
 
/*
 * issue a challenge
 */
static int rxkad_issue_challenge(struct rxrpc_connection *conn)
{
<------>struct rxkad_challenge challenge;
<------>struct rxrpc_wire_header whdr;
<------>struct msghdr msg;
<------>struct kvec iov[2];
<------>size_t len;
<------>u32 serial;
<------>int ret;
 
<------>_enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
 
<------>ret = key_validate(conn->server_key);
<------>if (ret < 0)
<------><------>return ret;
 
<------>get_random_bytes(&conn->security_nonce, sizeof(conn->security_nonce));
 
<------>challenge.version	= htonl(2);
<------>challenge.nonce		= htonl(conn->security_nonce);
<------>challenge.min_level	= htonl(0);
<------>challenge.__padding	= 0;
 
<------>msg.msg_name	= &conn->params.peer->srx.transport;
<------>msg.msg_namelen	= conn->params.peer->srx.transport_len;
<------>msg.msg_control	= NULL;
<------>msg.msg_controllen = 0;
<------>msg.msg_flags	= 0;
 
<------>whdr.epoch	= htonl(conn->proto.epoch);
<------>whdr.cid	= htonl(conn->proto.cid);
<------>whdr.callNumber	= 0;
<------>whdr.seq	= 0;
<------>whdr.type	= RXRPC_PACKET_TYPE_CHALLENGE;
<------>whdr.flags	= conn->out_clientflag;
<------>whdr.userStatus	= 0;
<------>whdr.securityIndex = conn->security_ix;
<------>whdr._rsvd	= 0;
<------>whdr.serviceId	= htons(conn->service_id);
 
<------>iov[0].iov_base	= &whdr;
<------>iov[0].iov_len	= sizeof(whdr);
<------>iov[1].iov_base	= &challenge;
<------>iov[1].iov_len	= sizeof(challenge);
 
<------>len = iov[0].iov_len + iov[1].iov_len;
 
<------>serial = atomic_inc_return(&conn->serial);
<------>whdr.serial = htonl(serial);
<------>_proto("Tx CHALLENGE %%%u", serial);
 
<------>ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
<------>if (ret < 0) {
<------><------>trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
<------><------><------><------>    rxrpc_tx_point_rxkad_challenge);
<------><------>return -EAGAIN;
<------>}
 
<------>conn->params.peer->last_tx_at = ktime_get_seconds();
<------>trace_rxrpc_tx_packet(conn->debug_id, &whdr,
<------><------><------>      rxrpc_tx_point_rxkad_challenge);
<------>_leave(" = 0");
<------>return 0;
}
 
/*
 * send a Kerberos security response
 */
static int rxkad_send_response(struct rxrpc_connection *conn,
<------><------><------>       struct rxrpc_host_header *hdr,
<------><------><------>       struct rxkad_response *resp,
<------><------><------>       const struct rxkad_key *s2)
{
<------>struct rxrpc_wire_header whdr;
<------>struct msghdr msg;
<------>struct kvec iov[3];
<------>size_t len;
<------>u32 serial;
<------>int ret;
 
<------>_enter("");
 
<------>msg.msg_name	= &conn->params.peer->srx.transport;
<------>msg.msg_namelen	= conn->params.peer->srx.transport_len;
<------>msg.msg_control	= NULL;
<------>msg.msg_controllen = 0;
<------>msg.msg_flags	= 0;
 
<------>memset(&whdr, 0, sizeof(whdr));
<------>whdr.epoch	= htonl(hdr->epoch);
<------>whdr.cid	= htonl(hdr->cid);
<------>whdr.type	= RXRPC_PACKET_TYPE_RESPONSE;
<------>whdr.flags	= conn->out_clientflag;
<------>whdr.securityIndex = hdr->securityIndex;
<------>whdr.serviceId	= htons(hdr->serviceId);
 
<------>iov[0].iov_base	= &whdr;
<------>iov[0].iov_len	= sizeof(whdr);
<------>iov[1].iov_base	= resp;
<------>iov[1].iov_len	= sizeof(*resp);
<------>iov[2].iov_base	= (void *)s2->ticket;
<------>iov[2].iov_len	= s2->ticket_len;
 
<------>len = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len;
 
<------>serial = atomic_inc_return(&conn->serial);
<------>whdr.serial = htonl(serial);
<------>_proto("Tx RESPONSE %%%u", serial);
 
<------>ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 3, len);
<------>if (ret < 0) {
<------><------>trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
<------><------><------><------>    rxrpc_tx_point_rxkad_response);
<------><------>return -EAGAIN;
<------>}
 
<------>conn->params.peer->last_tx_at = ktime_get_seconds();
<------>_leave(" = 0");
<------>return 0;
}
 
/*
 * calculate the response checksum
 */
static void rxkad_calc_response_checksum(struct rxkad_response *response)
{
<------>u32 csum = 1000003;
<------>int loop;
<------>u8 *p = (u8 *) response;
 
<------>for (loop = sizeof(*response); loop > 0; loop--)
<------><------>csum = csum * 0x10204081 + *p++;
 
<------>response->encrypted.checksum = htonl(csum);
}
 
/*
 * encrypt the response packet
 */
static int rxkad_encrypt_response(struct rxrpc_connection *conn,
<------><------><------><------>  struct rxkad_response *resp,
<------><------><------><------>  const struct rxkad_key *s2)
{
<------>struct skcipher_request *req;
<------>struct rxrpc_crypt iv;
<------>struct scatterlist sg[1];
 
<------>req = skcipher_request_alloc(&conn->cipher->base, GFP_NOFS);
<------>if (!req)
<------><------>return -ENOMEM;
 
<------>/* continue encrypting from where we left off */
<------>memcpy(&iv, s2->session_key, sizeof(iv));
 
<------>sg_init_table(sg, 1);
<------>sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
<------>skcipher_request_set_sync_tfm(req, conn->cipher);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
<------>crypto_skcipher_encrypt(req);
<------>skcipher_request_free(req);
<------>return 0;
}
 
/*
 * respond to a challenge packet
 */
static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
<------><------><------><------>      struct sk_buff *skb,
<------><------><------><------>      u32 *_abort_code)
{
<------>const struct rxrpc_key_token *token;
<------>struct rxkad_challenge challenge;
<------>struct rxkad_response *resp;
<------>struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
<------>const char *eproto;
<------>u32 version, nonce, min_level, abort_code;
<------>int ret;
 
<------>_enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
 
<------>eproto = tracepoint_string("chall_no_key");
<------>abort_code = RX_PROTOCOL_ERROR;
<------>if (!conn->params.key)
<------><------>goto protocol_error;
 
<------>abort_code = RXKADEXPIRED;
<------>ret = key_validate(conn->params.key);
<------>if (ret < 0)
<------><------>goto other_error;
 
<------>eproto = tracepoint_string("chall_short");
<------>abort_code = RXKADPACKETSHORT;
<------>if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
<------><------><------>  &challenge, sizeof(challenge)) < 0)
<------><------>goto protocol_error;
 
<------>version = ntohl(challenge.version);
<------>nonce = ntohl(challenge.nonce);
<------>min_level = ntohl(challenge.min_level);
 
<------>_proto("Rx CHALLENGE %%%u { v=%u n=%u ml=%u }",
<------>       sp->hdr.serial, version, nonce, min_level);
 
<------>eproto = tracepoint_string("chall_ver");
<------>abort_code = RXKADINCONSISTENCY;
<------>if (version != RXKAD_VERSION)
<------><------>goto protocol_error;
 
<------>abort_code = RXKADLEVELFAIL;
<------>ret = -EACCES;
<------>if (conn->params.security_level < min_level)
<------><------>goto other_error;
 
<------>token = conn->params.key->payload.data[0];
 
<------>/* build the response packet */
<------>resp = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
<------>if (!resp)
<------><------>return -ENOMEM;
 
<------>resp->version			= htonl(RXKAD_VERSION);
<------>resp->encrypted.epoch		= htonl(conn->proto.epoch);
<------>resp->encrypted.cid		= htonl(conn->proto.cid);
<------>resp->encrypted.securityIndex	= htonl(conn->security_ix);
<------>resp->encrypted.inc_nonce	= htonl(nonce + 1);
<------>resp->encrypted.level		= htonl(conn->params.security_level);
<------>resp->kvno			= htonl(token->kad->kvno);
<------>resp->ticket_len		= htonl(token->kad->ticket_len);
<------>resp->encrypted.call_id[0]	= htonl(conn->channels[0].call_counter);
<------>resp->encrypted.call_id[1]	= htonl(conn->channels[1].call_counter);
<------>resp->encrypted.call_id[2]	= htonl(conn->channels[2].call_counter);
<------>resp->encrypted.call_id[3]	= htonl(conn->channels[3].call_counter);
 
<------>/* calculate the response checksum and then do the encryption */
<------>rxkad_calc_response_checksum(resp);
<------>ret = rxkad_encrypt_response(conn, resp, token->kad);
<------>if (ret == 0)
<------><------>ret = rxkad_send_response(conn, &sp->hdr, resp, token->kad);
<------>kfree(resp);
<------>return ret;
 
protocol_error:
<------>trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
<------>ret = -EPROTO;
other_error:
<------>*_abort_code = abort_code;
<------>return ret;
}
 
/*
 * decrypt the kerberos IV ticket in the response
 */
static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
<------><------><------><------>struct sk_buff *skb,
<------><------><------><------>void *ticket, size_t ticket_len,
<------><------><------><------>struct rxrpc_crypt *_session_key,
<------><------><------><------>time64_t *_expiry,
<------><------><------><------>u32 *_abort_code)
{
<------>struct skcipher_request *req;
<------>struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
<------>struct rxrpc_crypt iv, key;
<------>struct scatterlist sg[1];
<------>struct in_addr addr;
<------>unsigned int life;
<------>const char *eproto;
<------>time64_t issue, now;
<------>bool little_endian;
<------>int ret;
<------>u32 abort_code;
<------>u8 *p, *q, *name, *end;
 
<------>_enter("{%d},{%x}", conn->debug_id, key_serial(conn->server_key));
 
<------>*_expiry = 0;
 
<------>ret = key_validate(conn->server_key);
<------>if (ret < 0) {
<------><------>switch (ret) {
<------><------>case -EKEYEXPIRED:
<------><------><------>abort_code = RXKADEXPIRED;
<------><------><------>goto other_error;
<------><------>default:
<------><------><------>abort_code = RXKADNOAUTH;
<------><------><------>goto other_error;
<------><------>}
<------>}
 
<------>ASSERT(conn->server_key->payload.data[0] != NULL);
<------>ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
 
<------>memcpy(&iv, &conn->server_key->payload.data[2], sizeof(iv));
 
<------>ret = -ENOMEM;
<------>req = skcipher_request_alloc(conn->server_key->payload.data[0],
<------><------><------><------>     GFP_NOFS);
<------>if (!req)
<------><------>goto temporary_error;
 
<------>sg_init_one(&sg[0], ticket, ticket_len);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, sg, sg, ticket_len, iv.x);
<------>crypto_skcipher_decrypt(req);
<------>skcipher_request_free(req);
 
<------>p = ticket;
<------>end = p + ticket_len;
 
#define Z(field)					\
<------>({						\
<------><------>u8 *__str = p;				\
<------><------>eproto = tracepoint_string("rxkad_bad_"#field); \
<------><------>q = memchr(p, 0, end - p);		\
<------><------>if (!q || q - p > (field##_SZ))		\
<------><------><------>goto bad_ticket;		\
<------><------>for (; p < q; p++)			\
<------><------><------>if (!isprint(*p))		\
<------><------><------><------>goto bad_ticket;	\
<------><------>p++;					\
<------><------>__str;					\
<------>})
 
<------>/* extract the ticket flags */
<------>_debug("KIV FLAGS: %x", *p);
<------>little_endian = *p & 1;
<------>p++;
 
<------>/* extract the authentication name */
<------>name = Z(ANAME);
<------>_debug("KIV ANAME: %s", name);
 
<------>/* extract the principal's instance */
<------>name = Z(INST);
<------>_debug("KIV INST : %s", name);
 
<------>/* extract the principal's authentication domain */
<------>name = Z(REALM);
<------>_debug("KIV REALM: %s", name);
 
<------>eproto = tracepoint_string("rxkad_bad_len");
<------>if (end - p < 4 + 8 + 4 + 2)
<------><------>goto bad_ticket;
 
<------>/* get the IPv4 address of the entity that requested the ticket */
<------>memcpy(&addr, p, sizeof(addr));
<------>p += 4;
<------>_debug("KIV ADDR : %pI4", &addr);
 
<------>/* get the session key from the ticket */
<------>memcpy(&key, p, sizeof(key));
<------>p += 8;
<------>_debug("KIV KEY  : %08x %08x", ntohl(key.n[0]), ntohl(key.n[1]));
<------>memcpy(_session_key, &key, sizeof(key));
 
<------>/* get the ticket's lifetime */
<------>life = *p++ * 5 * 60;
<------>_debug("KIV LIFE : %u", life);
 
<------>/* get the issue time of the ticket */
<------>if (little_endian) {
<------><------>__le32 stamp;
<------><------>memcpy(&stamp, p, 4);
<------><------>issue = rxrpc_u32_to_time64(le32_to_cpu(stamp));
<------>} else {
<------><------>__be32 stamp;
<------><------>memcpy(&stamp, p, 4);
<------><------>issue = rxrpc_u32_to_time64(be32_to_cpu(stamp));
<------>}
<------>p += 4;
<------>now = ktime_get_real_seconds();
<------>_debug("KIV ISSUE: %llx [%llx]", issue, now);
 
<------>/* check the ticket is in date */
<------>if (issue > now) {
<------><------>abort_code = RXKADNOAUTH;
<------><------>ret = -EKEYREJECTED;
<------><------>goto other_error;
<------>}
 
<------>if (issue < now - life) {
<------><------>abort_code = RXKADEXPIRED;
<------><------>ret = -EKEYEXPIRED;
<------><------>goto other_error;
<------>}
 
<------>*_expiry = issue + life;
 
<------>/* get the service name */
<------>name = Z(SNAME);
<------>_debug("KIV SNAME: %s", name);
 
<------>/* get the service instance name */
<------>name = Z(INST);
<------>_debug("KIV SINST: %s", name);
<------>return 0;
 
bad_ticket:
<------>trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
<------>abort_code = RXKADBADTICKET;
<------>ret = -EPROTO;
other_error:
<------>*_abort_code = abort_code;
<------>return ret;
temporary_error:
<------>return ret;
}
 
/*
 * decrypt the response packet
 */
static void rxkad_decrypt_response(struct rxrpc_connection *conn,
<------><------><------><------>   struct rxkad_response *resp,
<------><------><------><------>   const struct rxrpc_crypt *session_key)
{
<------>struct skcipher_request *req = rxkad_ci_req;
<------>struct scatterlist sg[1];
<------>struct rxrpc_crypt iv;
 
<------>_enter(",,%08x%08x",
<------>       ntohl(session_key->n[0]), ntohl(session_key->n[1]));
 
<------>mutex_lock(&rxkad_ci_mutex);
<------>if (crypto_sync_skcipher_setkey(rxkad_ci, session_key->x,
<------><------><------><------><------>sizeof(*session_key)) < 0)
<------><------>BUG();
 
<------>memcpy(&iv, session_key, sizeof(iv));
 
<------>sg_init_table(sg, 1);
<------>sg_set_buf(sg, &resp->encrypted, sizeof(resp->encrypted));
<------>skcipher_request_set_sync_tfm(req, rxkad_ci);
<------>skcipher_request_set_callback(req, 0, NULL, NULL);
<------>skcipher_request_set_crypt(req, sg, sg, sizeof(resp->encrypted), iv.x);
<------>crypto_skcipher_decrypt(req);
<------>skcipher_request_zero(req);
 
<------>mutex_unlock(&rxkad_ci_mutex);
 
<------>_leave("");
}
 
/*
 * verify a response
 */
static int rxkad_verify_response(struct rxrpc_connection *conn,
<------><------><------><------> struct sk_buff *skb,
<------><------><------><------> u32 *_abort_code)
{
<------>struct rxkad_response *response;
<------>struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
<------>struct rxrpc_crypt session_key;
<------>const char *eproto;
<------>time64_t expiry;
<------>void *ticket;
<------>u32 abort_code, version, kvno, ticket_len, level;
<------>__be32 csum;
<------>int ret, i;
 
<------>_enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
 
<------>ret = -ENOMEM;
<------>response = kzalloc(sizeof(struct rxkad_response), GFP_NOFS);
<------>if (!response)
<------><------>goto temporary_error;
 
<------>eproto = tracepoint_string("rxkad_rsp_short");
<------>abort_code = RXKADPACKETSHORT;
<------>if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
<------><------><------>  response, sizeof(*response)) < 0)
<------><------>goto protocol_error;
<------>if (!pskb_pull(skb, sizeof(*response)))
<------><------>BUG();
 
<------>version = ntohl(response->version);
<------>ticket_len = ntohl(response->ticket_len);
<------>kvno = ntohl(response->kvno);
<------>_proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
<------>       sp->hdr.serial, version, kvno, ticket_len);
 
<------>eproto = tracepoint_string("rxkad_rsp_ver");
<------>abort_code = RXKADINCONSISTENCY;
<------>if (version != RXKAD_VERSION)
<------><------>goto protocol_error;
 
<------>eproto = tracepoint_string("rxkad_rsp_tktlen");
<------>abort_code = RXKADTICKETLEN;
<------>if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
<------><------>goto protocol_error;
 
<------>eproto = tracepoint_string("rxkad_rsp_unkkey");
<------>abort_code = RXKADUNKNOWNKEY;
<------>if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
<------><------>goto protocol_error;
 
<------>/* extract the kerberos ticket and decrypt and decode it */
<------>ret = -ENOMEM;
<------>ticket = kmalloc(ticket_len, GFP_NOFS);
<------>if (!ticket)
<------><------>goto temporary_error_free_resp;
 
<------>eproto = tracepoint_string("rxkad_tkt_short");
<------>abort_code = RXKADPACKETSHORT;
<------>if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
<------><------><------>  ticket, ticket_len) < 0)
<------><------>goto protocol_error_free;
 
<------>ret = rxkad_decrypt_ticket(conn, skb, ticket, ticket_len, &session_key,
<------><------><------><------>   &expiry, _abort_code);
<------>if (ret < 0)
<------><------>goto temporary_error_free_ticket;
 
<------>/* use the session key from inside the ticket to decrypt the
<------> * response */
<------>rxkad_decrypt_response(conn, response, &session_key);
 
<------>eproto = tracepoint_string("rxkad_rsp_param");
<------>abort_code = RXKADSEALEDINCON;
<------>if (ntohl(response->encrypted.epoch) != conn->proto.epoch)
<------><------>goto protocol_error_free;
<------>if (ntohl(response->encrypted.cid) != conn->proto.cid)
<------><------>goto protocol_error_free;
<------>if (ntohl(response->encrypted.securityIndex) != conn->security_ix)
<------><------>goto protocol_error_free;
<------>csum = response->encrypted.checksum;
<------>response->encrypted.checksum = 0;
<------>rxkad_calc_response_checksum(response);
<------>eproto = tracepoint_string("rxkad_rsp_csum");
<------>if (response->encrypted.checksum != csum)
<------><------>goto protocol_error_free;
 
<------>spin_lock(&conn->bundle->channel_lock);
<------>for (i = 0; i < RXRPC_MAXCALLS; i++) {
<------><------>struct rxrpc_call *call;
<------><------>u32 call_id = ntohl(response->encrypted.call_id[i]);
 
<------><------>eproto = tracepoint_string("rxkad_rsp_callid");
<------><------>if (call_id > INT_MAX)
<------><------><------>goto protocol_error_unlock;
 
<------><------>eproto = tracepoint_string("rxkad_rsp_callctr");
<------><------>if (call_id < conn->channels[i].call_counter)
<------><------><------>goto protocol_error_unlock;
 
<------><------>eproto = tracepoint_string("rxkad_rsp_callst");
<------><------>if (call_id > conn->channels[i].call_counter) {
<------><------><------>call = rcu_dereference_protected(
<------><------><------><------>conn->channels[i].call,
<------><------><------><------>lockdep_is_held(&conn->bundle->channel_lock));
<------><------><------>if (call && call->state < RXRPC_CALL_COMPLETE)
<------><------><------><------>goto protocol_error_unlock;
<------><------><------>conn->channels[i].call_counter = call_id;
<------><------>}
<------>}
<------>spin_unlock(&conn->bundle->channel_lock);
 
<------>eproto = tracepoint_string("rxkad_rsp_seq");
<------>abort_code = RXKADOUTOFSEQUENCE;
<------>if (ntohl(response->encrypted.inc_nonce) != conn->security_nonce + 1)
<------><------>goto protocol_error_free;
 
<------>eproto = tracepoint_string("rxkad_rsp_level");
<------>abort_code = RXKADLEVELFAIL;
<------>level = ntohl(response->encrypted.level);
<------>if (level > RXRPC_SECURITY_ENCRYPT)
<------><------>goto protocol_error_free;
<------>conn->params.security_level = level;
 
<------>/* create a key to hold the security data and expiration time - after
<------> * this the connection security can be handled in exactly the same way
<------> * as for a client connection */
<------>ret = rxrpc_get_server_data_key(conn, &session_key, expiry, kvno);
<------>if (ret < 0)
<------><------>goto temporary_error_free_ticket;
 
<------>kfree(ticket);
<------>kfree(response);
<------>_leave(" = 0");
<------>return 0;
 
protocol_error_unlock:
<------>spin_unlock(&conn->bundle->channel_lock);
protocol_error_free:
<------>kfree(ticket);
protocol_error:
<------>kfree(response);
<------>trace_rxrpc_rx_eproto(NULL, sp->hdr.serial, eproto);
<------>*_abort_code = abort_code;
<------>return -EPROTO;
 
temporary_error_free_ticket:
<------>kfree(ticket);
temporary_error_free_resp:
<------>kfree(response);
temporary_error:
<------>/* Ignore the response packet if we got a temporary error such as
<------> * ENOMEM.  We just want to send the challenge again.  Note that we
<------> * also come out this way if the ticket decryption fails.
<------> */
<------>return ret;
}
 
/*
 * clear the connection security
 */
static void rxkad_clear(struct rxrpc_connection *conn)
{
<------>_enter("");
 
<------>if (conn->cipher)
<------><------>crypto_free_sync_skcipher(conn->cipher);
}
 
/*
 * Initialise the rxkad security service.
 */
static int rxkad_init(void)
{
<------>struct crypto_sync_skcipher *tfm;
<------>struct skcipher_request *req;
 
<------>/* pin the cipher we need so that the crypto layer doesn't invoke
<------> * keventd to go get it */
<------>tfm = crypto_alloc_sync_skcipher("pcbc(fcrypt)", 0, 0);
<------>if (IS_ERR(tfm))
<------><------>return PTR_ERR(tfm);
 
<------>req = skcipher_request_alloc(&tfm->base, GFP_KERNEL);
<------>if (!req)
<------><------>goto nomem_tfm;
 
<------>rxkad_ci_req = req;
<------>rxkad_ci = tfm;
<------>return 0;
 
nomem_tfm:
<------>crypto_free_sync_skcipher(tfm);
<------>return -ENOMEM;
}
 
/*
 * Clean up the rxkad security service.
 */
static void rxkad_exit(void)
{
<------>crypto_free_sync_skcipher(rxkad_ci);
<------>skcipher_request_free(rxkad_ci_req);
}
 
/*
 * RxRPC Kerberos-based security
 */
const struct rxrpc_security rxkad = {
<------>.name				= "rxkad",
<------>.security_index			= RXRPC_SECURITY_RXKAD,
<------>.no_key_abort			= RXKADUNKNOWNKEY,
<------>.init				= rxkad_init,
<------>.exit				= rxkad_exit,
<------>.init_connection_security	= rxkad_init_connection_security,
<------>.prime_packet_security		= rxkad_prime_packet_security,
<------>.secure_packet			= rxkad_secure_packet,
<------>.verify_packet			= rxkad_verify_packet,
<------>.free_call_crypto		= rxkad_free_call_crypto,
<------>.locate_data			= rxkad_locate_data,
<------>.issue_challenge		= rxkad_issue_challenge,
<------>.respond_to_challenge		= rxkad_respond_to_challenge,
<------>.verify_response		= rxkad_verify_response,
<------>.clear				= rxkad_clear,
};