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rxkad.c
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/* Kerberos-based RxRPC security
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#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_skcipher *rxkad_ci;
static DEFINE_MUTEX(rxkad_ci_mutex);
/*
* initialise connection security
*/
static int rxkad_init_connection_security(struct rxrpc_connection *conn)
{
struct crypto_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_skcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(ci)) {
_debug("no cipher");
ret = PTR_ERR(ci);
goto error;
}
if (crypto_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 rxrpc_key_token *token;
SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
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;
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_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_zero(req);
memcpy(&conn->csum_iv, tmpbuf + 2, sizeof(conn->csum_iv));
kfree(tmpbuf);
_leave(" = 0");
return 0;
}
/*
* 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 rxrpc_skb_priv *sp;
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxkad_level1_hdr hdr;
struct rxrpc_crypt iv;
struct scatterlist sg;
u16 check;
sp = rxrpc_skb(skb);
_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_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)
{
const struct rxrpc_key_token *token;
struct rxkad_level2_hdr rxkhdr;
struct rxrpc_skb_priv *sp;
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg[16];
struct sk_buff *trailer;
unsigned int len;
u16 check;
int nsg;
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_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 */
nsg = skb_cow_data(skb, 0, &trailer);
err = -ENOMEM;
if (nsg < 0 || nsg > 16)
goto out;
len = data_size + call->conn->size_align - 1;
len &= ~(call->conn->size_align - 1);
sg_init_table(sg, nsg);
skb_to_sgvec(skb, sg, 0, len);
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;
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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;
/* 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_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);
break;
case RXRPC_SECURITY_ENCRYPT:
ret = rxkad_secure_packet_encrypt(call, skb, data_size,
sechdr);
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 rxkad_level1_hdr sechdr;
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg[16];
struct sk_buff *trailer;
u32 data_size, buf;
u16 check;
int nsg;
_enter("");
if (len < 8) {
rxrpc_abort_call("V1H", call, seq, RXKADSEALEDINCON, EPROTO);
goto protocol_error;
}
/* Decrypt the skbuff in-place. TODO: We really want to decrypt
* directly into the target buffer.
*/
nsg = skb_cow_data(skb, 0, &trailer);
if (nsg < 0 || nsg > 16)
goto nomem;
sg_init_table(sg, nsg);
skb_to_sgvec(skb, sg, offset, 8);
/* start the decryption afresh */
memset(&iv, 0, sizeof(iv));
skcipher_request_set_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) {
rxrpc_abort_call("XV1", call, seq, RXKADDATALEN, EPROTO);
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) {
rxrpc_abort_call("V1C", call, seq, RXKADSEALEDINCON, EPROTO);
goto protocol_error;
}
if (data_size > len) {
rxrpc_abort_call("V1L", call, seq, RXKADDATALEN, EPROTO);
goto protocol_error;
}
_leave(" = 0 [dlen=%x]", data_size);
return 0;
protocol_error:
rxrpc_send_abort_packet(call);
_leave(" = -EPROTO");
return -EPROTO;
nomem:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* 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)
{
const struct rxrpc_key_token *token;
struct rxkad_level2_hdr sechdr;
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist _sg[4], *sg;
struct sk_buff *trailer;
u32 data_size, buf;
u16 check;
int nsg;
_enter(",{%d}", skb->len);
if (len < 8) {
rxrpc_abort_call("V2H", call, seq, RXKADSEALEDINCON, EPROTO);
goto protocol_error;
}
/* Decrypt the skbuff in-place. TODO: We really want to decrypt
* directly into the target buffer.
*/
nsg = skb_cow_data(skb, 0, &trailer);
if (nsg < 0)
goto nomem;
sg = _sg;
if (unlikely(nsg > 4)) {
sg = kmalloc(sizeof(*sg) * nsg, GFP_NOIO);
if (!sg)
goto nomem;
}
sg_init_table(sg, nsg);
skb_to_sgvec(skb, sg, offset, len);
/* decrypt from the session key */
token = call->conn->params.key->payload.data[0];
memcpy(&iv, token->kad->session_key, sizeof(iv));
skcipher_request_set_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) {
rxrpc_abort_call("XV2", call, seq, RXKADDATALEN, EPROTO);
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) {
rxrpc_abort_call("V2C", call, seq, RXKADSEALEDINCON, EPROTO);
goto protocol_error;
}
if (data_size > len) {
rxrpc_abort_call("V2L", call, seq, RXKADDATALEN, EPROTO);
goto protocol_error;
}
_leave(" = 0 [dlen=%x]", data_size);
return 0;
protocol_error:
rxrpc_send_abort_packet(call);
_leave(" = -EPROTO");
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)
{
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg;
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;
/* 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_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) {
rxrpc_abort_call("VCK", call, seq, RXKADSEALEDINCON, EPROTO);
rxrpc_send_abort_packet(call);
_leave(" = -EPROTO [csum failed]");
return -EPROTO;
}
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);
case RXRPC_SECURITY_ENCRYPT:
return rxkad_verify_packet_2(call, skb, offset, len, seq);
default:
return -ENOANO;
}
}
/*
* 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->params.key));
ret = key_validate(conn->params.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.sin;
msg.msg_namelen = sizeof(conn->params.peer->srx.transport.sin);
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->params.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) {
_debug("sendmsg failed: %d", ret);
return -EAGAIN;
}
_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.sin;
msg.msg_namelen = sizeof(conn->params.peer->srx.transport.sin);
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) {
_debug("sendmsg failed: %d", ret);
return -EAGAIN;
}
_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 void rxkad_encrypt_response(struct rxrpc_connection *conn,
struct rxkad_response *resp,
const struct rxkad_key *s2)
{
SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg[1];
/* 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_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_zero(req);
}
/*
* 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
__attribute__((aligned(8))); /* must be aligned for crypto */
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
u32 version, nonce, min_level, abort_code;
int ret;
_enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
if (!conn->params.key) {
_leave(" = -EPROTO [no key]");
return -EPROTO;
}
ret = key_validate(conn->params.key);
if (ret < 0) {
*_abort_code = RXKADEXPIRED;
return ret;
}
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);
abort_code = RXKADINCONSISTENCY;
if (version != RXKAD_VERSION)
goto protocol_error;
abort_code = RXKADLEVELFAIL;
if (conn->params.security_level < min_level)
goto protocol_error;
token = conn->params.key->payload.data[0];
/* build the response packet */
memset(&resp, 0, sizeof(resp));
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);
rxkad_encrypt_response(conn, &resp, token->kad);
return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
protocol_error:
*_abort_code = abort_code;
_leave(" = -EPROTO [%d]", abort_code);
return -EPROTO;
}
/*
* decrypt the kerberos IV ticket in the response
*/
static int rxkad_decrypt_ticket(struct rxrpc_connection *conn,
void *ticket, size_t ticket_len,
struct rxrpc_crypt *_session_key,
time_t *_expiry,
u32 *_abort_code)
{
struct skcipher_request *req;
struct rxrpc_crypt iv, key;
struct scatterlist sg[1];
struct in_addr addr;
unsigned int life;
time_t issue, now;
bool little_endian;
int ret;
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 error;
default:
*_abort_code = RXKADNOAUTH;
goto 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));
req = skcipher_request_alloc(conn->server_key->payload.data[0],
GFP_NOFS);
if (!req) {
*_abort_code = RXKADNOAUTH;
ret = -ENOMEM;
goto 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(size) \
({ \
u8 *__str = p; \
q = memchr(p, 0, end - p); \
if (!q || q - p > (size)) \
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_SZ);
_debug("KIV ANAME: %s", name);
/* extract the principal's instance */
name = Z(INST_SZ);
_debug("KIV INST : %s", name);
/* extract the principal's authentication domain */
name = Z(REALM_SZ);
_debug("KIV REALM: %s", name);
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 = le32_to_cpu(stamp);
} else {
__be32 stamp;
memcpy(&stamp, p, 4);
issue = be32_to_cpu(stamp);
}
p += 4;
now = get_seconds();
_debug("KIV ISSUE: %lx [%lx]", issue, now);
/* check the ticket is in date */
if (issue > now) {
*_abort_code = RXKADNOAUTH;
ret = -EKEYREJECTED;
goto error;
}
if (issue < now - life) {
*_abort_code = RXKADEXPIRED;
ret = -EKEYEXPIRED;
goto error;
}
*_expiry = issue + life;
/* get the service name */
name = Z(SNAME_SZ);
_debug("KIV SNAME: %s", name);
/* get the service instance name */
name = Z(INST_SZ);
_debug("KIV SINST: %s", name);
ret = 0;
error:
_leave(" = %d", ret);
return ret;
bad_ticket:
*_abort_code = RXKADBADTICKET;
ret = -EBADMSG;
goto error;
}
/*
* decrypt the response packet
*/
static void rxkad_decrypt_response(struct rxrpc_connection *conn,
struct rxkad_response *resp,
const struct rxrpc_crypt *session_key)
{
SKCIPHER_REQUEST_ON_STACK(req, rxkad_ci);
struct scatterlist sg[1];
struct rxrpc_crypt iv;
_enter(",,%08x%08x",
ntohl(session_key->n[0]), ntohl(session_key->n[1]));
ASSERT(rxkad_ci != NULL);
mutex_lock(&rxkad_ci_mutex);
if (crypto_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));