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rxkad.c
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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.
*/
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/ctype.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#define rxrpc_debug rxkad_debug
#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 */
unsigned rxrpc_debug;
module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(debug, "rxkad debugging mask");
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 */
};
MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos)");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
/*
* 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_blkcipher *rxkad_ci;
static DEFINE_MUTEX(rxkad_ci_mutex);
/*
* initialise connection security
*/
static int rxkad_init_connection_security(struct rxrpc_connection *conn)
{
struct rxrpc_key_payload *payload;
struct crypto_blkcipher *ci;
int ret;
_enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
payload = conn->key->payload.data;
conn->security_ix = payload->k.security_index;
ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(ci)) {
_debug("no cipher");
ret = PTR_ERR(ci);
goto error;
}
if (crypto_blkcipher_setkey(ci, payload->k.session_key,
sizeof(payload->k.session_key)) < 0)
BUG();
switch (conn->security_level) {
case RXRPC_SECURITY_PLAIN:
break;
case RXRPC_SECURITY_AUTH:
conn->size_align = 8;
conn->security_size = sizeof(struct rxkad_level1_hdr);
conn->header_size += sizeof(struct rxkad_level1_hdr);
break;
case RXRPC_SECURITY_ENCRYPT:
conn->size_align = 8;
conn->security_size = sizeof(struct rxkad_level2_hdr);
conn->header_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 void rxkad_prime_packet_security(struct rxrpc_connection *conn)
{
struct rxrpc_key_payload *payload;
struct blkcipher_desc desc;
struct scatterlist sg[2];
struct rxrpc_crypt iv;
struct {
__be32 x[4];
} tmpbuf __attribute__((aligned(16))); /* must all be in same page */
_enter("");
if (!conn->key)
return;
payload = conn->key->payload.data;
memcpy(&iv, payload->k.session_key, sizeof(iv));
desc.tfm = conn->cipher;
desc.info = iv.x;
desc.flags = 0;
tmpbuf.x[0] = conn->epoch;
tmpbuf.x[1] = conn->cid;
tmpbuf.x[2] = 0;
tmpbuf.x[3] = htonl(conn->security_ix);
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]);
_leave("");
}
/*
* 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;
struct blkcipher_desc desc;
struct rxrpc_crypt iv;
struct scatterlist sg[2];
struct {
struct rxkad_level1_hdr hdr;
__be32 first; /* first four bytes of data and padding */
} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
u16 check;
sp = rxrpc_skb(skb);
_enter("");
check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
data_size |= (u32) check << 16;
tmpbuf.hdr.data_size = htonl(data_size);
memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first));
/* start the encryption afresh */
memset(&iv, 0, sizeof(iv));
desc.tfm = call->conn->cipher;
desc.info = iv.x;
desc.flags = 0;
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
memcpy(sechdr, &tmpbuf, sizeof(tmpbuf));
_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_payload *payload;
struct rxkad_level2_hdr rxkhdr
__attribute__((aligned(8))); /* must be all on one page */
struct rxrpc_skb_priv *sp;
struct blkcipher_desc desc;
struct rxrpc_crypt iv;
struct scatterlist sg[16];
struct sk_buff *trailer;
unsigned len;
u16 check;
int nsg;
sp = rxrpc_skb(skb);
_enter("");
check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
rxkhdr.data_size = htonl(data_size | (u32) check << 16);
rxkhdr.checksum = 0;
/* encrypt from the session key */
payload = call->conn->key->payload.data;
memcpy(&iv, payload->k.session_key, sizeof(iv));
desc.tfm = call->conn->cipher;
desc.info = iv.x;
desc.flags = 0;
sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr));
/* we want to encrypt the skbuff in-place */
nsg = skb_cow_data(skb, 0, &trailer);
if (nsg < 0 || nsg > 16)
return -ENOMEM;
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);
crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
_leave(" = 0");
return 0;
}
/*
* checksum an RxRPC packet header
*/
static int rxkad_secure_packet(const struct rxrpc_call *call,
struct sk_buff *skb,
size_t data_size,
void *sechdr)
{
struct rxrpc_skb_priv *sp;
struct blkcipher_desc desc;
struct rxrpc_crypt iv;
struct scatterlist sg[2];
struct {
__be32 x[2];
} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
__be32 x;
u32 y;
int ret;
sp = rxrpc_skb(skb);
_enter("{%d{%x}},{#%u},%zu,",
call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq),
data_size);
if (!call->conn->cipher)
return 0;
ret = key_validate(call->conn->key);
if (ret < 0)
return ret;
/* continue encrypting from where we left off */
memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
desc.tfm = call->conn->cipher;
desc.info = iv.x;
desc.flags = 0;
/* calculate the security checksum */
x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
tmpbuf.x[0] = sp->hdr.callNumber;
tmpbuf.x[1] = x;
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
y = ntohl(tmpbuf.x[1]);
y = (y >> 16) & 0xffff;
if (y == 0)
y = 1; /* zero checksums are not permitted */
sp->hdr.cksum = htons(y);
switch (call->conn->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_auth(const struct rxrpc_call *call,
struct sk_buff *skb,
u32 *_abort_code)
{
struct rxkad_level1_hdr sechdr;
struct rxrpc_skb_priv *sp;
struct blkcipher_desc desc;
struct rxrpc_crypt iv;
struct scatterlist sg[16];
struct sk_buff *trailer;
u32 data_size, buf;
u16 check;
int nsg;
_enter("");
sp = rxrpc_skb(skb);
/* we want to decrypt the skbuff in-place */
nsg = skb_cow_data(skb, 0, &trailer);
if (nsg < 0 || nsg > 16)
goto nomem;
sg_init_table(sg, nsg);
skb_to_sgvec(skb, sg, 0, 8);
/* start the decryption afresh */
memset(&iv, 0, sizeof(iv));
desc.tfm = call->conn->cipher;
desc.info = iv.x;
desc.flags = 0;
crypto_blkcipher_decrypt_iv(&desc, sg, sg, 8);
/* remove the decrypted packet length */
if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
goto datalen_error;
if (!skb_pull(skb, sizeof(sechdr)))
BUG();
buf = ntohl(sechdr.data_size);
data_size = buf & 0xffff;
check = buf >> 16;
check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
check &= 0xffff;
if (check != 0) {
*_abort_code = RXKADSEALEDINCON;
goto protocol_error;
}
/* shorten the packet to remove the padding */
if (data_size > skb->len)
goto datalen_error;
else if (data_size < skb->len)
skb->len = data_size;
_leave(" = 0 [dlen=%x]", data_size);
return 0;
datalen_error:
*_abort_code = RXKADDATALEN;
protocol_error:
_leave(" = -EPROTO");
return -EPROTO;
nomem:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* wholly decrypt a packet (level 2 security)
*/
static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
struct sk_buff *skb,
u32 *_abort_code)
{
const struct rxrpc_key_payload *payload;
struct rxkad_level2_hdr sechdr;
struct rxrpc_skb_priv *sp;
struct blkcipher_desc desc;
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);
sp = rxrpc_skb(skb);
/* we want to decrypt the skbuff in-place */
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, 0, skb->len);
/* decrypt from the session key */
payload = call->conn->key->payload.data;
memcpy(&iv, payload->k.session_key, sizeof(iv));
desc.tfm = call->conn->cipher;
desc.info = iv.x;
desc.flags = 0;
crypto_blkcipher_decrypt_iv(&desc, sg, sg, skb->len);
if (sg != _sg)
kfree(sg);
/* remove the decrypted packet length */
if (skb_copy_bits(skb, 0, &sechdr, sizeof(sechdr)) < 0)
goto datalen_error;
if (!skb_pull(skb, sizeof(sechdr)))
BUG();
buf = ntohl(sechdr.data_size);
data_size = buf & 0xffff;
check = buf >> 16;
check ^= ntohl(sp->hdr.seq ^ sp->hdr.callNumber);
check &= 0xffff;
if (check != 0) {
*_abort_code = RXKADSEALEDINCON;
goto protocol_error;
}
/* shorten the packet to remove the padding */
if (data_size > skb->len)
goto datalen_error;
else if (data_size < skb->len)
skb->len = data_size;
_leave(" = 0 [dlen=%x]", data_size);
return 0;
datalen_error:
*_abort_code = RXKADDATALEN;
protocol_error:
_leave(" = -EPROTO");
return -EPROTO;
nomem:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* verify the security on a received packet
*/
static int rxkad_verify_packet(const struct rxrpc_call *call,
struct sk_buff *skb,
u32 *_abort_code)
{
struct blkcipher_desc desc;
struct rxrpc_skb_priv *sp;
struct rxrpc_crypt iv;
struct scatterlist sg[2];
struct {
__be32 x[2];
} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
__be32 x;
__be16 cksum;
u32 y;
int ret;
sp = rxrpc_skb(skb);
_enter("{%d{%x}},{#%u}",
call->debug_id, key_serial(call->conn->key),
ntohl(sp->hdr.seq));
if (!call->conn->cipher)
return 0;
if (sp->hdr.securityIndex != 2) {
*_abort_code = RXKADINCONSISTENCY;
_leave(" = -EPROTO [not rxkad]");
return -EPROTO;
}
/* continue encrypting from where we left off */
memcpy(&iv, call->conn->csum_iv.x, sizeof(iv));
desc.tfm = call->conn->cipher;
desc.info = iv.x;
desc.flags = 0;
/* validate the security checksum */
x = htonl(call->channel << (32 - RXRPC_CIDSHIFT));
x |= sp->hdr.seq & cpu_to_be32(0x3fffffff);
tmpbuf.x[0] = call->call_id;
tmpbuf.x[1] = x;
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf));
y = ntohl(tmpbuf.x[1]);
y = (y >> 16) & 0xffff;
if (y == 0)
y = 1; /* zero checksums are not permitted */
cksum = htons(y);
if (sp->hdr.cksum != cksum) {
*_abort_code = RXKADSEALEDINCON;
_leave(" = -EPROTO [csum failed]");
return -EPROTO;
}
switch (call->conn->security_level) {
case RXRPC_SECURITY_PLAIN:
ret = 0;
break;
case RXRPC_SECURITY_AUTH:
ret = rxkad_verify_packet_auth(call, skb, _abort_code);
break;
case RXRPC_SECURITY_ENCRYPT:
ret = rxkad_verify_packet_encrypt(call, skb, _abort_code);
break;
default:
ret = -ENOANO;
break;
}
_leave(" = %d", ret);
return ret;
}
/*
* issue a challenge
*/
static int rxkad_issue_challenge(struct rxrpc_connection *conn)
{
struct rxkad_challenge challenge;
struct rxrpc_header hdr;
struct msghdr msg;
struct kvec iov[2];
size_t len;
int ret;
_enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
ret = key_validate(conn->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->trans->peer->srx.transport.sin;
msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
hdr.epoch = conn->epoch;
hdr.cid = conn->cid;
hdr.callNumber = 0;
hdr.seq = 0;
hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
hdr.flags = conn->out_clientflag;
hdr.userStatus = 0;
hdr.securityIndex = conn->security_ix;
hdr._rsvd = 0;
hdr.serviceId = conn->service_id;
iov[0].iov_base = &hdr;
iov[0].iov_len = sizeof(hdr);
iov[1].iov_base = &challenge;
iov[1].iov_len = sizeof(challenge);
len = iov[0].iov_len + iov[1].iov_len;
hdr.serial = htonl(atomic_inc_return(&conn->serial));
_proto("Tx CHALLENGE %%%u", ntohl(hdr.serial));
ret = kernel_sendmsg(conn->trans->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_header *hdr,
struct rxkad_response *resp,
const struct rxkad_key *s2)
{
struct msghdr msg;
struct kvec iov[3];
size_t len;
int ret;
_enter("");
msg.msg_name = &conn->trans->peer->srx.transport.sin;
msg.msg_namelen = sizeof(conn->trans->peer->srx.transport.sin);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
hdr->epoch = conn->epoch;
hdr->seq = 0;
hdr->type = RXRPC_PACKET_TYPE_RESPONSE;
hdr->flags = conn->out_clientflag;
hdr->userStatus = 0;
hdr->_rsvd = 0;
iov[0].iov_base = hdr;
iov[0].iov_len = sizeof(*hdr);
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;
hdr->serial = htonl(atomic_inc_return(&conn->serial));
_proto("Tx RESPONSE %%%u", ntohl(hdr->serial));
ret = kernel_sendmsg(conn->trans->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);
}
/*
* load a scatterlist with a potentially split-page buffer
*/
static void rxkad_sg_set_buf2(struct scatterlist sg[2],
void *buf, size_t buflen)
{
int nsg = 1;
sg_init_table(sg, 2);
sg_set_buf(&sg[0], buf, buflen);
if (sg[0].offset + buflen > PAGE_SIZE) {
/* the buffer was split over two pages */
sg[0].length = PAGE_SIZE - sg[0].offset;
sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
nsg++;
}
sg_mark_end(&sg[nsg - 1]);
ASSERTCMP(sg[0].length + sg[1].length, ==, buflen);
}
/*
* encrypt the response packet
*/
static void rxkad_encrypt_response(struct rxrpc_connection *conn,
struct rxkad_response *resp,
const struct rxkad_key *s2)
{
struct blkcipher_desc desc;
struct rxrpc_crypt iv;
struct scatterlist sg[2];
/* continue encrypting from where we left off */
memcpy(&iv, s2->session_key, sizeof(iv));
desc.tfm = conn->cipher;
desc.info = iv.x;
desc.flags = 0;
rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
crypto_blkcipher_encrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
}
/*
* 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_payload *payload;
struct rxkad_challenge challenge;
struct rxkad_response resp
__attribute__((aligned(8))); /* must be aligned for crypto */
struct rxrpc_skb_priv *sp;
u32 version, nonce, min_level, abort_code;
int ret;
_enter("{%d,%x}", conn->debug_id, key_serial(conn->key));
if (!conn->key) {
_leave(" = -EPROTO [no key]");
return -EPROTO;
}
ret = key_validate(conn->key);
if (ret < 0) {
*_abort_code = RXKADEXPIRED;
return ret;
}
abort_code = RXKADPACKETSHORT;
sp = rxrpc_skb(skb);
if (skb_copy_bits(skb, 0, &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 }",
ntohl(sp->hdr.serial), version, nonce, min_level);
abort_code = RXKADINCONSISTENCY;
if (version != RXKAD_VERSION)
goto protocol_error;
abort_code = RXKADLEVELFAIL;
if (conn->security_level < min_level)
goto protocol_error;
payload = conn->key->payload.data;
/* build the response packet */
memset(&resp, 0, sizeof(resp));
resp.version = RXKAD_VERSION;
resp.encrypted.epoch = conn->epoch;
resp.encrypted.cid = conn->cid;
resp.encrypted.securityIndex = htonl(conn->security_ix);
resp.encrypted.call_id[0] =
(conn->channels[0] ? conn->channels[0]->call_id : 0);
resp.encrypted.call_id[1] =
(conn->channels[1] ? conn->channels[1]->call_id : 0);
resp.encrypted.call_id[2] =
(conn->channels[2] ? conn->channels[2]->call_id : 0);
resp.encrypted.call_id[3] =
(conn->channels[3] ? conn->channels[3]->call_id : 0);
resp.encrypted.inc_nonce = htonl(nonce + 1);
resp.encrypted.level = htonl(conn->security_level);
resp.kvno = htonl(payload->k.kvno);
resp.ticket_len = htonl(payload->k.ticket_len);
/* calculate the response checksum and then do the encryption */
rxkad_calc_response_checksum(&resp);
rxkad_encrypt_response(conn, &resp, &payload->k);
return rxkad_send_response(conn, &sp->hdr, &resp, &payload->k);
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 blkcipher_desc desc;
struct rxrpc_crypt iv, key;
struct scatterlist sg[1];
struct in_addr addr;
unsigned 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 != NULL);
ASSERTCMP((unsigned long) ticket & 7UL, ==, 0);
memcpy(&iv, &conn->server_key->type_data, sizeof(iv));
desc.tfm = conn->server_key->payload.data;
desc.info = iv.x;
desc.flags = 0;
sg_init_one(&sg[0], ticket, ticket_len);
crypto_blkcipher_decrypt_iv(&desc, sg, sg, ticket_len);
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)
{
struct blkcipher_desc desc;
struct scatterlist sg[2];
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_blkcipher_setkey(rxkad_ci, session_key->x,
sizeof(*session_key)) < 0)
BUG();
memcpy(&iv, session_key, sizeof(iv));
desc.tfm = rxkad_ci;
desc.info = iv.x;
desc.flags = 0;
rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
crypto_blkcipher_decrypt_iv(&desc, sg, sg, sizeof(resp->encrypted));
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