linux/net/rxrpc/rxkad.c
Linus Torvalds 1200b6809d Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:
 "Highlights:

   1) Support more Realtek wireless chips, from Jes Sorenson.

   2) New BPF types for per-cpu hash and arrap maps, from Alexei
      Starovoitov.

   3) Make several TCP sysctls per-namespace, from Nikolay Borisov.

   4) Allow the use of SO_REUSEPORT in order to do per-thread processing
   of incoming TCP/UDP connections.  The muxing can be done using a
   BPF program which hashes the incoming packet.  From Craig Gallek.

   5) Add a multiplexer for TCP streams, to provide a messaged based
      interface.  BPF programs can be used to determine the message
      boundaries.  From Tom Herbert.

   6) Add 802.1AE MACSEC support, from Sabrina Dubroca.

   7) Avoid factorial complexity when taking down an inetdev interface
      with lots of configured addresses.  We were doing things like
      traversing the entire address less for each address removed, and
      flushing the entire netfilter conntrack table for every address as
      well.

   8) Add and use SKB bulk free infrastructure, from Jesper Brouer.

   9) Allow offloading u32 classifiers to hardware, and implement for
      ixgbe, from John Fastabend.

  10) Allow configuring IRQ coalescing parameters on a per-queue basis,
      from Kan Liang.

  11) Extend ethtool so that larger link mode masks can be supported.
      From David Decotigny.

  12) Introduce devlink, which can be used to configure port link types
      (ethernet vs Infiniband, etc.), port splitting, and switch device
      level attributes as a whole.  From Jiri Pirko.

  13) Hardware offload support for flower classifiers, from Amir Vadai.

  14) Add "Local Checksum Offload".  Basically, for a tunneled packet
      the checksum of the outer header is 'constant' (because with the
      checksum field filled into the inner protocol header, the payload
      of the outer frame checksums to 'zero'), and we can take advantage
      of that in various ways.  From Edward Cree"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1548 commits)
  bonding: fix bond_get_stats()
  net: bcmgenet: fix dma api length mismatch
  net/mlx4_core: Fix backward compatibility on VFs
  phy: mdio-thunder: Fix some Kconfig typos
  lan78xx: add ndo_get_stats64
  lan78xx: handle statistics counter rollover
  RDS: TCP: Remove unused constant
  RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket
  net: smc911x: convert pxa dma to dmaengine
  team: remove duplicate set of flag IFF_MULTICAST
  bonding: remove duplicate set of flag IFF_MULTICAST
  net: fix a comment typo
  ethernet: micrel: fix some error codes
  ip_tunnels, bpf: define IP_TUNNEL_OPTS_MAX and use it
  bpf, dst: add and use dst_tclassid helper
  bpf: make skb->tc_classid also readable
  net: mvneta: bm: clarify dependencies
  cls_bpf: reset class and reuse major in da
  ldmvsw: Checkpatch sunvnet.c and sunvnet_common.c
  ldmvsw: Add ldmvsw.c driver code
  ...
2016-03-19 10:05:34 -07:00

1207 lines
29 KiB
C

/* 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 <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>
#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_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->key));
token = conn->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->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;
SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
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[0];
memcpy(&iv, token->kad->session_key, sizeof(iv));
tmpbuf.x[0] = htonl(conn->epoch);
tmpbuf.x[1] = htonl(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));
skcipher_request_set_tfm(req, conn->cipher);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x);
crypto_skcipher_encrypt(req);
skcipher_request_zero(req);
memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv));
ASSERTCMP((u32 __force)conn->csum_iv.n[0], ==, (u32 __force)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;
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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 = 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));
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
skcipher_request_set_tfm(req, call->conn->cipher);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x);
crypto_skcipher_encrypt(req);
skcipher_request_zero(req);
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;
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 ^ 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[0];
memcpy(&iv, token->kad->session_key, sizeof(iv));
sg_init_one(&sg[0], sechdr, sizeof(rxkhdr));
sg_init_one(&sg[1], &rxkhdr, sizeof(rxkhdr));
skcipher_request_set_tfm(req, call->conn->cipher);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, &sg[1], &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(const 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[2];
struct {
__be32 x[2];
} tmpbuf __attribute__((aligned(8))); /* must all be in same page */
u32 x, y;
int ret;
sp = rxrpc_skb(skb);
_enter("{%d{%x}},{#%u},%zu,",
call->debug_id, key_serial(call->conn->key), 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));
/* calculate the security checksum */
x = call->channel << (32 - RXRPC_CIDSHIFT);
x |= sp->hdr.seq & 0x3fffffff;
tmpbuf.x[0] = htonl(sp->hdr.callNumber);
tmpbuf.x[1] = htonl(x);
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
skcipher_request_set_tfm(req, call->conn->cipher);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x);
crypto_skcipher_encrypt(req);
skcipher_request_zero(req);
y = ntohl(tmpbuf.x[1]);
y = (y >> 16) & 0xffff;
if (y == 0)
y = 1; /* zero checksums are not permitted */
sp->hdr.cksum = 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;
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("");
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));
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);
/* 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 ^= 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;
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);
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[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, skb->len, iv.x);
crypto_skcipher_decrypt(req);
skcipher_request_zero(req);
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 ^= 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)
{
SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
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 */
u16 cksum;
u32 x, y;
int ret;
sp = rxrpc_skb(skb);
_enter("{%d{%x}},{#%u}",
call->debug_id, key_serial(call->conn->key), 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));
/* validate the security checksum */
x = call->channel << (32 - RXRPC_CIDSHIFT);
x |= sp->hdr.seq & 0x3fffffff;
tmpbuf.x[0] = htonl(call->call_id);
tmpbuf.x[1] = htonl(x);
sg_init_one(&sg[0], &tmpbuf, sizeof(tmpbuf));
sg_init_one(&sg[1], &tmpbuf, sizeof(tmpbuf));
skcipher_request_set_tfm(req, call->conn->cipher);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x);
crypto_skcipher_encrypt(req);
skcipher_request_zero(req);
y = ntohl(tmpbuf.x[1]);
cksum = (y >> 16) & 0xffff;
if (cksum == 0)
cksum = 1; /* zero checksums are not permitted */
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_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->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;
whdr.epoch = htonl(conn->epoch);
whdr.cid = htonl(conn->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->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_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->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;
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->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)
{
SKCIPHER_REQUEST_ON_STACK(req, conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg[2];
/* continue encrypting from where we left off */
memcpy(&iv, s2->session_key, sizeof(iv));
rxkad_sg_set_buf2(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;
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 }",
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[0];
/* build the response packet */
memset(&resp, 0, sizeof(resp));
resp.version = htonl(RXKAD_VERSION);
resp.encrypted.epoch = htonl(conn->epoch);
resp.encrypted.cid = htonl(conn->cid);
resp.encrypted.securityIndex = htonl(conn->security_ix);
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);
resp.encrypted.call_id[0] =
htonl(conn->channels[0] ? conn->channels[0]->call_id : 0);
resp.encrypted.call_id[1] =
htonl(conn->channels[1] ? conn->channels[1]->call_id : 0);
resp.encrypted.call_id[2] =
htonl(conn->channels[2] ? conn->channels[2]->call_id : 0);
resp.encrypted.call_id[3] =
htonl(conn->channels[3] ? conn->channels[3]->call_id : 0);
/* 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[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_skcipher_setkey(rxkad_ci, session_key->x,
sizeof(*session_key)) < 0)
BUG();
memcpy(&iv, session_key, sizeof(iv));
rxkad_sg_set_buf2(sg, &resp->encrypted, sizeof(resp->encrypted));
skcipher_request_set_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
__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 }",
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 (ntohl(response.encrypted.epoch) != conn->epoch)
goto protocol_error_free;
if (ntohl(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 (ntohl(response.encrypted.inc_nonce) != 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_skcipher(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_skcipher("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_skcipher(rxkad_ci);
}
module_exit(rxkad_exit);