linux/net/rxrpc/rxkad.c

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/* Kerberos-based RxRPC security
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <keys/rxrpc-type.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 int 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 4)");
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 crypto_blkcipher *ci;
struct rxrpc_key_token *token;
int ret;
_enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
token = conn->key->payload.data;
conn->security_ix = token->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, token->kad->session_key,
sizeof(token->kad->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_token *token;
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;
token = conn->key->payload.data;
memcpy(&iv, token->kad->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_token *token;
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 int 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 */
token = call->conn->key->payload.data;
memcpy(&iv, token->kad->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_token *token;
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 */
token = call->conn->key->payload.data;
memcpy(&iv, token->kad->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 != RXRPC_SECURITY_RXKAD) {
*_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_token *token;
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;
token = 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(token->kad->kvno);
resp.ticket_len = htonl(token->kad->ticket_len);
/* 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 blkcipher_desc desc;
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 != 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
__attribute__((aligned(8))); /* must be aligned for crypto */
struct rxrpc_skb_priv *sp;
struct rxrpc_crypt session_key;
time_t expiry;
void *ticket;
u32 abort_code, version, kvno, ticket_len, level;
__be32 csum;
int ret;
_enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));
abort_code = RXKADPACKETSHORT;
if (skb_copy_bits(skb, 0, &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);
sp = rxrpc_skb(skb);
_proto("Rx RESPONSE %%%u { v=%u kv=%u tl=%u }",
ntohl(sp->hdr.serial), version, kvno, ticket_len);
abort_code = RXKADINCONSISTENCY;
if (version != RXKAD_VERSION)
goto protocol_error;
abort_code = RXKADTICKETLEN;
if (ticket_len < 4 || ticket_len > MAXKRB5TICKETLEN)
goto protocol_error;
abort_code = RXKADUNKNOWNKEY;
if (kvno >= RXKAD_TKT_TYPE_KERBEROS_V5)
goto protocol_error;
/* extract the kerberos ticket and decrypt and decode it */
ticket = kmalloc(ticket_len, GFP_NOFS);
if (!ticket)
return -ENOMEM;
abort_code = RXKADPACKETSHORT;
if (skb_copy_bits(skb, 0, ticket, ticket_len) < 0)
goto protocol_error_free;
ret = rxkad_decrypt_ticket(conn, ticket, ticket_len, &session_key,
&expiry, &abort_code);
if (ret < 0) {
*_abort_code = abort_code;
kfree(ticket);
return ret;
}
/* use the session key from inside the ticket to decrypt the
* response */
rxkad_decrypt_response(conn, &response, &session_key);
abort_code = RXKADSEALEDINCON;
if (response.encrypted.epoch != conn->epoch)
goto protocol_error_free;
if (response.encrypted.cid != conn->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);
if (response.encrypted.checksum != csum)
goto protocol_error_free;
if (ntohl(response.encrypted.call_id[0]) > INT_MAX ||
ntohl(response.encrypted.call_id[1]) > INT_MAX ||
ntohl(response.encrypted.call_id[2]) > INT_MAX ||
ntohl(response.encrypted.call_id[3]) > INT_MAX)
goto protocol_error_free;
abort_code = RXKADOUTOFSEQUENCE;
if (response.encrypted.inc_nonce != htonl(conn->security_nonce + 1))
goto protocol_error_free;
abort_code = RXKADLEVELFAIL;
level = ntohl(response.encrypted.level);
if (level > RXRPC_SECURITY_ENCRYPT)
goto protocol_error_free;
conn->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) {
kfree(ticket);
return ret;
}
kfree(ticket);
_leave(" = 0");
return 0;
protocol_error_free:
kfree(ticket);
protocol_error:
*_abort_code = abort_code;
_leave(" = -EPROTO [%d]", abort_code);
return -EPROTO;
}
/*
* clear the connection security
*/
static void rxkad_clear(struct rxrpc_connection *conn)
{
_enter("");
if (conn->cipher)
crypto_free_blkcipher(conn->cipher);
}
/*
* RxRPC Kerberos-based security
*/
static struct rxrpc_security rxkad = {
.owner = THIS_MODULE,
.name = "rxkad",
.security_index = RXRPC_SECURITY_RXKAD,
.init_connection_security = rxkad_init_connection_security,
.prime_packet_security = rxkad_prime_packet_security,
.secure_packet = rxkad_secure_packet,
.verify_packet = rxkad_verify_packet,
.issue_challenge = rxkad_issue_challenge,
.respond_to_challenge = rxkad_respond_to_challenge,
.verify_response = rxkad_verify_response,
.clear = rxkad_clear,
};
static __init int rxkad_init(void)
{
_enter("");
/* pin the cipher we need so that the crypto layer doesn't invoke
* keventd to go get it */
rxkad_ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(rxkad_ci))
return PTR_ERR(rxkad_ci);
return rxrpc_register_security(&rxkad);
}
module_init(rxkad_init);
static __exit void rxkad_exit(void)
{
_enter("");
rxrpc_unregister_security(&rxkad);
crypto_free_blkcipher(rxkad_ci);
}
module_exit(rxkad_exit);