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iwd/src/ie.c

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/*
*
* Wireless daemon for Linux
*
* Copyright (C) 2013-2014 Intel Corporation. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <errno.h>
#include <ell/ell.h>
#include "util.h"
#include "ie.h"
static const uint8_t ieee_oui[3] = { 0x00, 0x0f, 0xac };
void ie_tlv_iter_init(struct ie_tlv_iter *iter, const unsigned char *tlv,
unsigned int len)
{
iter->tlv = tlv;
iter->max = len;
iter->pos = 0;
}
void ie_tlv_iter_recurse(struct ie_tlv_iter *iter,
struct ie_tlv_iter *recurse)
{
recurse->tlv = iter->data;
recurse->max = iter->len;
recurse->pos = 0;
}
unsigned int ie_tlv_iter_get_tag(struct ie_tlv_iter *iter)
{
return iter->tag;
}
bool ie_tlv_iter_next(struct ie_tlv_iter *iter)
{
const unsigned char *tlv = iter->tlv + iter->pos;
const unsigned char *end = iter->tlv + iter->max;
unsigned int tag;
unsigned int len;
if (iter->pos >= iter->max)
return false;
tag = *tlv++;
len = *tlv++;
if (tlv + len > end)
return false;
iter->tag = tag;
iter->len = len;
iter->data = tlv;
iter->pos = tlv + len - iter->tlv;
return true;
}
#define TLV_HEADER_LEN 2
static bool ie_tlv_builder_init_recurse(struct ie_tlv_builder *builder,
unsigned char *tlv, unsigned int size)
{
if (!builder)
return false;
if (!tlv) {
memset(builder->buf, 0, MAX_BUILDER_SIZE);
builder->tlv = builder->buf;
builder->max = MAX_BUILDER_SIZE;
} else {
builder->tlv = tlv;
builder->max = size;
}
builder->pos = 0;
builder->parent = NULL;
builder->tag = 0xffff;
builder->len = 0;
return true;
}
bool ie_tlv_builder_init(struct ie_tlv_builder *builder)
{
return ie_tlv_builder_init_recurse(builder, NULL, 0);
}
static void ie_tlv_builder_write_header(struct ie_tlv_builder *builder)
{
unsigned char *tlv = builder->tlv + builder->pos;
tlv[0] = builder->tag;
tlv[1] = builder->len;
}
bool ie_tlv_builder_set_length(struct ie_tlv_builder *builder,
unsigned int new_len)
{
unsigned int new_pos = builder->pos + TLV_HEADER_LEN + new_len;
if (new_pos > builder->max)
return false;
if (builder->parent)
ie_tlv_builder_set_length(builder->parent, new_pos);
builder->len = new_len;
return true;
}
bool ie_tlv_builder_next(struct ie_tlv_builder *builder, unsigned int new_tag)
{
if (new_tag > 0xff)
return false;
if (builder->tag != 0xffff) {
ie_tlv_builder_write_header(builder);
builder->pos += TLV_HEADER_LEN + builder->len;
}
if (!ie_tlv_builder_set_length(builder, 0))
return false;
builder->tag = new_tag;
return true;
}
unsigned char *ie_tlv_builder_get_data(struct ie_tlv_builder *builder)
{
return builder->tlv + TLV_HEADER_LEN + builder->pos;
}
bool ie_tlv_builder_recurse(struct ie_tlv_builder *builder,
struct ie_tlv_builder *recurse)
{
unsigned char *end = builder->buf + builder->max;
unsigned char *data = ie_tlv_builder_get_data(builder);
if (!ie_tlv_builder_init_recurse(recurse, data, end - data))
return false;
recurse->parent = builder;
return true;
}
void ie_tlv_builder_finalize(struct ie_tlv_builder *builder,
unsigned int *out_len)
{
unsigned int len;
ie_tlv_builder_write_header(builder);
len = builder->pos + TLV_HEADER_LEN + builder->len;
if (out_len)
*out_len = len;
}
/* 802.11, Section 8.4.2.27.2 */
static bool ie_parse_cipher_suite(const uint8_t *data,
enum ie_rsn_cipher_suite *out)
{
/*
* Compare the OUI to the ones we know. OUI Format is found in
* Figure 8-187 of 802.11
*/
if (!memcmp(data, ieee_oui, 3)) {
/* Suite type from Table 8-99 */
switch (data[3]) {
case 0:
*out = IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER;
return true;
case 1:
*out = IE_RSN_CIPHER_SUITE_WEP40;
return true;
case 2:
*out = IE_RSN_CIPHER_SUITE_TKIP;
return true;
case 4:
*out = IE_RSN_CIPHER_SUITE_CCMP;
return true;
case 5:
*out = IE_RSN_CIPHER_SUITE_WEP104;
return true;
case 6:
*out = IE_RSN_CIPHER_SUITE_BIP;
return true;
case 7:
*out = IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC;
return true;
default:
return false;
}
}
return false;
}
/* 802.11, Section 8.4.2.27.2 */
static bool ie_parse_akm_suite(const uint8_t *data,
enum ie_rsn_akm_suite *out)
{
/*
* Compare the OUI to the ones we know. OUI Format is found in
* Figure 8-187 of 802.11
*/
if (!memcmp(data, ieee_oui, 3)) {
/* Suite type from Table 8-101 */
switch (data[3]) {
case 1:
*out = IE_RSN_AKM_SUITE_8021X;
return true;
case 2:
*out = IE_RSN_AKM_SUITE_PSK;
return true;
case 3:
*out = IE_RSN_AKM_SUITE_FT_OVER_8021X;
return true;
case 4:
*out = IE_RSN_AKM_SUITE_FT_USING_PSK;
return true;
case 5:
*out = IE_RSN_AKM_SUITE_8021X_SHA256;
return true;
case 6:
*out = IE_RSN_AKM_SUITE_PSK_SHA256;
return true;
case 7:
*out = IE_RSN_AKM_SUITE_TDLS;
return true;
case 8:
*out = IE_RSN_AKM_SUITE_SAE_SHA256;
return true;
case 9:
*out = IE_RSN_AKM_SUITE_FT_OVER_SAE_SHA256;
return true;
default:
return false;
}
}
return false;
}
static bool ie_parse_group_cipher(const uint8_t *data,
enum ie_rsn_cipher_suite *out)
{
enum ie_rsn_cipher_suite tmp;
bool r = ie_parse_cipher_suite(data, &tmp);
if (!r)
return r;
switch (tmp) {
case IE_RSN_CIPHER_SUITE_CCMP:
case IE_RSN_CIPHER_SUITE_TKIP:
case IE_RSN_CIPHER_SUITE_WEP104:
case IE_RSN_CIPHER_SUITE_WEP40:
case IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC:
break;
default:
return false;
}
*out = tmp;
return true;
}
static bool ie_parse_pairwise_cipher(const uint8_t *data,
enum ie_rsn_cipher_suite *out)
{
enum ie_rsn_cipher_suite tmp;
bool r = ie_parse_cipher_suite(data, &tmp);
if (!r)
return r;
switch (tmp) {
case IE_RSN_CIPHER_SUITE_CCMP:
case IE_RSN_CIPHER_SUITE_TKIP:
case IE_RSN_CIPHER_SUITE_WEP104:
case IE_RSN_CIPHER_SUITE_WEP40:
case IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER:
break;
default:
return false;
}
*out = tmp;
return true;
}
static bool ie_parse_group_management_cipher(const uint8_t *data,
enum ie_rsn_cipher_suite *out)
{
enum ie_rsn_cipher_suite tmp;
bool r = ie_parse_cipher_suite(data, &tmp);
if (!r)
return r;
switch (tmp) {
case IE_RSN_CIPHER_SUITE_BIP:
break;
default:
return false;
}
*out = tmp;
return true;
}
#define RSNE_ADVANCE(data, len, step) \
data += step; \
len -= step; \
\
if (len == 0) \
goto done \
int ie_parse_rsne(struct ie_tlv_iter *iter, struct ie_rsn_info *out_info)
{
const uint8_t *data = iter->data;
size_t len = iter->len;
uint16_t version;
struct ie_rsn_info info;
uint16_t count;
uint16_t i;
memset(&info, 0, sizeof(info));
info.group_cipher = IE_RSN_CIPHER_SUITE_CCMP;
info.pairwise_ciphers = IE_RSN_CIPHER_SUITE_CCMP;
info.akm_suites = IE_RSN_AKM_SUITE_8021X;
/* Parse Version field */
if (len < 2)
return -EMSGSIZE;
version = l_get_le16(data);
if (version != 0x01)
return -EBADMSG;
RSNE_ADVANCE(data, len, 2);
/* Parse Group Cipher Suite field */
if (len < 4)
return -EBADMSG;
if (!ie_parse_group_cipher(data, &info.group_cipher))
return -ERANGE;
RSNE_ADVANCE(data, len, 4);
/* Parse Pairwise Cipher Suite Count field */
if (len < 2)
return -EBADMSG;
count = l_get_le16(data);
/*
* The spec doesn't seem to explicitly say what to do in this case,
* so we assume this situation is invalid.
*/
if (count == 0)
return -EINVAL;
data += 2;
len -= 2;
if (len < 4 * count)
return -EBADMSG;
/* Parse Pairwise Cipher Suite List field */
for (i = 0, info.pairwise_ciphers = 0; i < count; i++) {
enum ie_rsn_cipher_suite suite;
if (!ie_parse_pairwise_cipher(data + i * 4, &suite))
return -ERANGE;
info.pairwise_ciphers |= suite;
}
RSNE_ADVANCE(data, len, count * 4);
/* Parse AKM Suite Count field */
if (len < 2)
return -EBADMSG;
count = l_get_le16(data);
if (count == 0)
return -EINVAL;
data += 2;
len -= 2;
if (len < 4 * count)
return -EBADMSG;
/* Parse AKM Suite List field */
for (i = 0, info.akm_suites = 0; i < count; i++) {
enum ie_rsn_akm_suite suite;
if (!ie_parse_akm_suite(data + i * 4, &suite))
return -ERANGE;
info.akm_suites |= suite;
}
RSNE_ADVANCE(data, len, count * 4);
if (len < 2)
return -EBADMSG;
info.preauthentication = util_is_bit_set(data[0], 0);
info.no_pairwise = util_is_bit_set(data[0], 1);
info.ptksa_replay_counter = util_bit_field(data[0], 2, 2);
info.gtksa_replay_counter = util_bit_field(data[0], 4, 2);
info.mfpr = util_is_bit_set(data[0], 6);
info.mfpc = util_is_bit_set(data[0], 7);
info.peerkey_enabled = util_is_bit_set(data[1], 1);
info.spp_a_msdu_capable = util_is_bit_set(data[1], 2);
info.spp_a_msdu_required = util_is_bit_set(data[1], 3);
info.pbac = util_is_bit_set(data[1], 4);
info.extended_key_id = util_is_bit_set(data[1], 5);
RSNE_ADVANCE(data, len, 2);
/*
* BIP—default group management cipher suite in an RSNA with
* management frame protection enabled
*/
if (info.mfpc)
info.group_management_cipher = IE_RSN_CIPHER_SUITE_BIP;
/* Parse PMKID Count field */
if (len < 2)
return -EBADMSG;
info.num_pmkids = l_get_le16(data);
RSNE_ADVANCE(data, len, 2);
if (info.num_pmkids > 0) {
if (len < 16 * info.num_pmkids)
return -EBADMSG;
/*
* Parse PMKID List field.
*
* We simply assign the pointer to the PMKIDs to the structure.
* The PMKIDs are fixed size, 16 bytes each.
*/
info.pmkids = data;
RSNE_ADVANCE(data, len, info.num_pmkids * 16);
}
/* Parse Group Management Cipher Suite field */
if (len < 4)
return -EBADMSG;
if (!ie_parse_group_management_cipher(data,
&info.group_management_cipher))
return -ERANGE;
RSNE_ADVANCE(data, len, 4);
return -EBADMSG;
done:
if (out_info)
memcpy(out_info, &info, sizeof(info));
return 0;
}
int ie_parse_rsne_from_data(const uint8_t *data, size_t len,
struct ie_rsn_info *info)
{
struct ie_tlv_iter iter;
ie_tlv_iter_init(&iter, data, len);
if (!ie_tlv_iter_next(&iter))
return -EMSGSIZE;
if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_RSN)
return -EPROTOTYPE;
return ie_parse_rsne(&iter, info);
}
/* 802.11, Section 8.4.2.27.2 */
static bool ie_build_cipher_suite(uint8_t *data,
const enum ie_rsn_cipher_suite suite)
{
switch (suite) {
case IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER:
memcpy(data, ieee_oui, 3);
data[3] = 0;
return true;
case IE_RSN_CIPHER_SUITE_WEP40:
memcpy(data, ieee_oui, 3);
data[3] = 1;
return true;
case IE_RSN_CIPHER_SUITE_TKIP:
memcpy(data, ieee_oui, 3);
data[3] = 2;
return true;
case IE_RSN_CIPHER_SUITE_CCMP:
memcpy(data, ieee_oui, 3);
data[3] = 4;
return true;
case IE_RSN_CIPHER_SUITE_WEP104:
memcpy(data, ieee_oui, 3);
data[3] = 5;
return true;
case IE_RSN_CIPHER_SUITE_BIP:
memcpy(data, ieee_oui, 3);
data[3] = 6;
return true;
case IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC:
memcpy(data, ieee_oui, 3);
data[3] = 7;
return true;
}
return false;
}
/* 802.11, Section 8.4.2.27.2 */
static bool ie_build_akm_suite(uint8_t *data,
enum ie_rsn_akm_suite suite)
{
switch (suite) {
case IE_RSN_AKM_SUITE_8021X:
memcpy(data, ieee_oui, 3);
data[3] = 1;
return true;
case IE_RSN_AKM_SUITE_PSK:
memcpy(data, ieee_oui, 3);
data[3] = 2;
return true;
case IE_RSN_AKM_SUITE_FT_OVER_8021X:
memcpy(data, ieee_oui, 3);
data[3] = 3;
return true;
case IE_RSN_AKM_SUITE_FT_USING_PSK:
memcpy(data, ieee_oui, 3);
data[3] = 4;
return true;
case IE_RSN_AKM_SUITE_8021X_SHA256:
memcpy(data, ieee_oui, 3);
data[3] = 5;
return true;
case IE_RSN_AKM_SUITE_PSK_SHA256:
memcpy(data, ieee_oui, 3);
data[3] = 6;
return true;
case IE_RSN_AKM_SUITE_TDLS:
memcpy(data, ieee_oui, 3);
data[3] = 7;
return true;
case IE_RSN_AKM_SUITE_SAE_SHA256:
memcpy(data, ieee_oui, 3);
data[3] = 8;
return true;
case IE_RSN_AKM_SUITE_FT_OVER_SAE_SHA256:
memcpy(data, ieee_oui, 3);
data[3] = 9;
return true;
}
return false;
}
/*
* Generate an RSNE IE based on the information found in info.
* The to array must be 256 bytes in size
*
* In theory it is possible to generate 257 byte IE RSNs (1 byte for IE Type,
* 1 byte for Length and 255 bytes of data) but we don't support this
* possibility.
*/
bool ie_build_rsne(const struct ie_rsn_info *info, uint8_t *to)
{
/* These are the only valid pairwise suites */
static enum ie_rsn_cipher_suite pairwise_suites[] = {
IE_RSN_CIPHER_SUITE_CCMP,
IE_RSN_CIPHER_SUITE_TKIP,
IE_RSN_CIPHER_SUITE_WEP104,
IE_RSN_CIPHER_SUITE_WEP40,
IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER,
};
unsigned int pos;
unsigned int i;
uint8_t *countptr;
uint16_t count;
enum ie_rsn_akm_suite akm_suite;
to[0] = IE_TYPE_RSN;
/* Version field, always 1 */
pos = 2;
l_put_le16(1, to + pos);
pos += 2;
/* Group Data Cipher Suite */
if (!ie_build_cipher_suite(to + pos, info->group_cipher))
return false;
pos += 4;
/* Save position for Pairwise Cipher Suite Count field */
countptr = to + pos;
pos += 2;
for (i = 0, count = 0; i < L_ARRAY_SIZE(pairwise_suites); i++) {
enum ie_rsn_cipher_suite suite = pairwise_suites[i];
if (!(info->pairwise_ciphers & suite))
continue;
if (pos + 4 > 242)
return false;
if (!ie_build_cipher_suite(to + pos, suite))
return false;
pos += 4;
count += 1;
}
l_put_le16(count, countptr);
/* Save position for AKM Suite Count field */
countptr = to + pos;
pos += 2;
akm_suite = IE_RSN_AKM_SUITE_8021X;
count = 0;
for (count = 0, akm_suite = IE_RSN_AKM_SUITE_8021X;
akm_suite <= IE_RSN_AKM_SUITE_FT_OVER_SAE_SHA256;
akm_suite <<= 1) {
if (!(info->akm_suites & akm_suite))
continue;
if (pos + 4 > 248)
return false;
if (!ie_build_akm_suite(to + pos, akm_suite))
return false;
pos += 4;
count += 1;
}
l_put_le16(count, countptr);
/* Bits 0 - 7 of RSNE Capabilities field */
to[pos] = 0;
if (info->preauthentication)
to[pos] |= 0x1;
if (info->no_pairwise)
to[pos] |= 0x2;
to[pos] |= info->ptksa_replay_counter << 2;
to[pos] |= info->gtksa_replay_counter << 4;
if (info->mfpr)
to[pos] |= 0x40;
if (info->mfpc)
to[pos] |= 0x80;
pos += 1;
/* Bits 8 - 15 of RSNE Capabilities field */
to[pos] = 0;
if (info->peerkey_enabled)
to[pos] |= 0x2;
if (info->spp_a_msdu_capable)
to[pos] |= 0x4;
if (info->spp_a_msdu_required)
to[pos] |= 0x8;
if (info->pbac)
to[pos] |= 0x10;
if (info->extended_key_id)
to[pos] |= 0x20;
pos += 1;
/* Short hand the generated RSNE if possible */
if (info->num_pmkids == 0) {
/* No Group Management Cipher Suite */
if (to[pos - 2] == 0 && to[pos - 1] == 0) {
pos -= 2;
goto done;
} else if (!info->mfpc)
goto done;
else if (info->group_management_cipher ==
IE_RSN_CIPHER_SUITE_BIP)
goto done;
}
/* PMKID Count */
l_put_le16(info->num_pmkids, to + pos);
pos += 2;
if (pos + info->num_pmkids * 16 > 252)
return false;
/* PMKID List */
memcpy(to + pos, info->pmkids, 16 * info->num_pmkids);
pos += 16 * info->num_pmkids;
if (!info->mfpc)
goto done;
if (info->group_management_cipher == IE_RSN_CIPHER_SUITE_BIP)
goto done;
/* Group Management Cipher Suite */
if (!ie_build_cipher_suite(to, info->group_management_cipher))
return false;
pos += 4;
done:
to[1] = pos - 2;
return true;
}
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