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EAP-pwd: Add support for fragmentation

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Signed-hostap: Dan Harkins <dharkins@lounge.org>
This commit is contained in:
Dan Harkins 2012-02-11 12:46:30 +02:00 committed by Jouni Malinen
parent 27c9d333d4
commit 5ea93947ca
3 changed files with 484 additions and 141 deletions
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13
src/eap_common/eap_pwd_common.h
View File

@ -37,16 +37,17 @@ typedef struct group_definition_ {
* EAP-pwd header, included on all payloads
* L(1 bit) | M(1 bit) | exch(6 bits) | total_length(if L is set)
*/
#define EAP_PWD_HDR_SIZE 1
#define EAP_PWD_OPCODE_ID_EXCH 1
#define EAP_PWD_OPCODE_COMMIT_EXCH 2
#define EAP_PWD_OPCODE_CONFIRM_EXCH 3
#define EAP_PWD_GET_LENGTH_BIT(x) ((x)->lm_exch & 0x80)
#define EAP_PWD_SET_LENGTH_BIT(x) ((x)->lm_exch |= 0x80)
#define EAP_PWD_GET_MORE_BIT(x) ((x)->lm_exch & 0x40)
#define EAP_PWD_SET_MORE_BIT(x) ((x)->lm_exch |= 0x40)
#define EAP_PWD_GET_EXCHANGE(x) ((x)->lm_exch & 0x3f)
#define EAP_PWD_SET_EXCHANGE(x,y) ((x)->lm_exch |= (y))
#define EAP_PWD_GET_LENGTH_BIT(x) ((x) & 0x80)
#define EAP_PWD_SET_LENGTH_BIT(x) ((x) |= 0x80)
#define EAP_PWD_GET_MORE_BIT(x) ((x) & 0x40)
#define EAP_PWD_SET_MORE_BIT(x) ((x) |= 0x40)
#define EAP_PWD_GET_EXCHANGE(x) ((x) & 0x3f)
#define EAP_PWD_SET_EXCHANGE(x,y) ((x) |= (y))
/* EAP-pwd-ID payload */
struct eap_pwd_id {

301
src/eap_peer/eap_pwd.c
View File

@ -32,6 +32,12 @@ struct eap_pwd_data {
u16 group_num;
EAP_PWD_group *grp;
struct wpabuf *inbuf;
size_t in_frag_pos;
struct wpabuf *outbuf;
size_t out_frag_pos;
size_t mtu;
BIGNUM *k;
BIGNUM *private_value;
BIGNUM *server_scalar;
@ -69,7 +75,7 @@ static const char * eap_pwd_state_txt(int state)
static void eap_pwd_state(struct eap_pwd_data *data, int state)
{
wpa_printf(MSG_INFO, "EAP-PWD: %s -> %s",
wpa_printf(MSG_DEBUG, "EAP-PWD: %s -> %s",
eap_pwd_state_txt(data->state), eap_pwd_state_txt(state));
data->state = state;
}
@ -124,6 +130,10 @@ static void * eap_pwd_init(struct eap_sm *sm)
os_memcpy(data->password, password, password_len);
data->password_len = password_len;
data->out_frag_pos = data->in_frag_pos = 0;
data->inbuf = data->outbuf = NULL;
data->mtu = 1020; /* default from RFC 5931, make it configurable! */
data->state = PWD_ID_Req;
return data;
@ -174,23 +184,24 @@ static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len)
}
static struct wpabuf *
static void
eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
struct eap_method_ret *ret,
const struct wpabuf *reqData,
const u8 *payload, size_t payload_len)
{
struct eap_pwd_id *id;
struct wpabuf *resp;
if (data->state != PWD_ID_Req) {
ret->ignore = TRUE;
return NULL;
eap_pwd_state(data, FAILURE);
return;
}
if (payload_len < sizeof(struct eap_pwd_id)) {
ret->ignore = TRUE;
return NULL;
eap_pwd_state(data, FAILURE);
return;
}
id = (struct eap_pwd_id *) payload;
@ -198,16 +209,18 @@ eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
if ((id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) ||
(id->prf != EAP_PWD_DEFAULT_PRF)) {
ret->ignore = TRUE;
return NULL;
eap_pwd_state(data, FAILURE);
return;
}
wpa_printf(MSG_DEBUG, "EAP-PWD (peer): server said group %d",
wpa_printf(MSG_DEBUG, "EAP-PWD (peer): using group %d",
data->group_num);
data->id_server = os_malloc(payload_len - sizeof(struct eap_pwd_id));
if (data->id_server == NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
return NULL;
eap_pwd_state(data, FAILURE);
return;
}
data->id_server_len = payload_len - sizeof(struct eap_pwd_id);
os_memcpy(data->id_server, id->identity, data->id_server_len);
@ -218,7 +231,8 @@ eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
NULL) {
wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for "
"group");
return NULL;
eap_pwd_state(data, FAILURE);
return;
}
/* compute PWE */
@ -228,39 +242,36 @@ eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
data->id_peer, data->id_peer_len,
id->token)) {
wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute PWE");
return NULL;
eap_pwd_state(data, FAILURE);
return;
}
wpa_printf(MSG_INFO, "EAP-PWD (peer): computed %d bit PWE...",
wpa_printf(MSG_DEBUG, "EAP-PWD (peer): computed %d bit PWE...",
BN_num_bits(data->grp->prime));
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
1 + sizeof(struct eap_pwd_id) + data->id_peer_len,
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp == NULL)
return NULL;
wpabuf_put_u8(resp, EAP_PWD_OPCODE_ID_EXCH);
wpabuf_put_be16(resp, data->group_num);
wpabuf_put_u8(resp, EAP_PWD_DEFAULT_RAND_FUNC);
wpabuf_put_u8(resp, EAP_PWD_DEFAULT_PRF);
wpabuf_put_data(resp, id->token, sizeof(id->token));
wpabuf_put_u8(resp, EAP_PWD_PREP_NONE);
wpabuf_put_data(resp, data->id_peer, data->id_peer_len);
data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) +
data->id_peer_len);
if (data->outbuf == NULL) {
eap_pwd_state(data, FAILURE);
return;
}
wpabuf_put_be16(data->outbuf, data->group_num);
wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC);
wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF);
wpabuf_put_data(data->outbuf, id->token, sizeof(id->token));
wpabuf_put_u8(data->outbuf, EAP_PWD_PREP_NONE);
wpabuf_put_data(data->outbuf, data->id_peer, data->id_peer_len);
eap_pwd_state(data, PWD_Commit_Req);
return resp;
}
static struct wpabuf *
static void
eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
struct eap_method_ret *ret,
const struct wpabuf *reqData,
const u8 *payload, size_t payload_len)
{
struct wpabuf *resp = NULL;
EC_POINT *K = NULL, *point = NULL;
BIGNUM *mask = NULL, *x = NULL, *y = NULL, *cofactor = NULL;
u16 offset;
@ -422,18 +433,15 @@ eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
1 + BN_num_bytes(data->grp->order) +
(2 * BN_num_bytes(data->grp->prime)),
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp == NULL)
data->outbuf = wpabuf_alloc(BN_num_bytes(data->grp->order) +
2 * BN_num_bytes(data->grp->prime));
if (data->outbuf == NULL)
goto fin;
wpabuf_put_u8(resp, EAP_PWD_OPCODE_COMMIT_EXCH);
/* we send the element as (x,y) follwed by the scalar */
wpabuf_put_data(resp, element, (2 * BN_num_bytes(data->grp->prime)));
wpabuf_put_data(resp, scalar, BN_num_bytes(data->grp->order));
wpabuf_put_data(data->outbuf, element,
2 * BN_num_bytes(data->grp->prime));
wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order));
fin:
os_free(scalar);
@ -443,22 +451,19 @@ fin:
BN_free(cofactor);
EC_POINT_free(K);
EC_POINT_free(point);
if (resp == NULL)
if (data->outbuf == NULL)
eap_pwd_state(data, FAILURE);
else
eap_pwd_state(data, PWD_Confirm_Req);
return resp;
}
static struct wpabuf *
static void
eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
struct eap_method_ret *ret,
const struct wpabuf *reqData,
const u8 *payload, size_t payload_len)
{
struct wpabuf *resp = NULL;
BIGNUM *x = NULL, *y = NULL;
HMAC_CTX ctx;
u32 cs;
@ -481,7 +486,7 @@ eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
/* each component of the cruft will be at most as big as the prime */
if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
wpa_printf(MSG_INFO, "EAP-PWD (server): debug allocation "
wpa_printf(MSG_INFO, "EAP-PWD (server): confirm allocation "
"fail");
goto fin;
}
@ -631,15 +636,6 @@ eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
/* all done */
H_Final(&ctx, conf);
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
1 + SHA256_DIGEST_LENGTH,
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp == NULL)
goto fin;
wpabuf_put_u8(resp, EAP_PWD_OPCODE_CONFIRM_EXCH);
wpabuf_put_data(resp, conf, SHA256_DIGEST_LENGTH);
if (compute_keys(data->grp, data->bnctx, data->k,
data->my_scalar, data->server_scalar, conf, ptr,
&cs, data->msk, data->emsk) < 0) {
@ -648,20 +644,24 @@ eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
goto fin;
}
data->outbuf = wpabuf_alloc(SHA256_DIGEST_LENGTH);
if (data->outbuf == NULL)
goto fin;
wpabuf_put_data(data->outbuf, conf, SHA256_DIGEST_LENGTH);
fin:
os_free(cruft);
BN_free(x);
BN_free(y);
ret->methodState = METHOD_DONE;
if (resp == NULL) {
if (data->outbuf == NULL) {
ret->decision = DECISION_FAIL;
eap_pwd_state(data, FAILURE);
} else {
ret->decision = DECISION_UNCOND_SUCC;
eap_pwd_state(data, SUCCESS);
}
return resp;
}
@ -671,42 +671,199 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
{
struct eap_pwd_data *data = priv;
struct wpabuf *resp = NULL;
const u8 *pos;
const u8 *pos, *buf;
size_t len;
u8 exch;
u16 tot_len = 0;
u8 lm_exch;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, reqData, &len);
if ((pos == NULL) || (len < 1)) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Got a frame but pos is %s and "
"len is %d",
pos == NULL ? "NULL" : "not NULL", (int) len);
ret->ignore = TRUE;
return NULL;
}
wpa_printf(MSG_INFO, "EAP-pwd: Received frame: opcode %d", *pos);
ret->ignore = FALSE;
ret->methodState = METHOD_MAY_CONT;
ret->decision = DECISION_FAIL;
ret->allowNotifications = FALSE;
exch = *pos & 0x3f;
switch (exch) {
case EAP_PWD_OPCODE_ID_EXCH:
resp = eap_pwd_perform_id_exchange(sm, data, ret, reqData,
pos + 1, len - 1);
lm_exch = *pos;
pos++; /* skip over the bits and the exch */
len--;
/*
* we're fragmenting so send out the next fragment
*/
if (data->out_frag_pos) {
/*
* this should be an ACK
*/
if (len)
wpa_printf(MSG_INFO, "Bad Response! Fragmenting but "
"not an ACK");
wpa_printf(MSG_DEBUG, "EAP-pwd: Got an ACK for a fragment");
/*
* check if there are going to be more fragments
*/
len = wpabuf_len(data->outbuf) - data->out_frag_pos;
if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
len = data->mtu - EAP_PWD_HDR_SIZE;
EAP_PWD_SET_MORE_BIT(lm_exch);
}
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE + len,
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp == NULL) {
wpa_printf(MSG_INFO, "Unable to allocate memory for "
"next fragment!");
return NULL;
}
wpabuf_put_u8(resp, lm_exch);
buf = wpabuf_head_u8(data->outbuf);
wpabuf_put_data(resp, buf + data->out_frag_pos, len);
data->out_frag_pos += len;
/*
* this is the last fragment so get rid of the out buffer
*/
if (data->out_frag_pos >= wpabuf_len(data->outbuf)) {
wpabuf_free(data->outbuf);
data->out_frag_pos = 0;
}
wpa_printf(MSG_DEBUG, "EAP-pwd: Send %s fragment of %d bytes",
data->out_frag_pos == 0 ? "last" : "next",
(int) len);
return resp;
}
/*
* see if this is a fragment that needs buffering
*
* if it's the first fragment there'll be a length field
*/
if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
tot_len = WPA_GET_BE16(pos);
wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments whose "
"total length = %d", tot_len);
data->inbuf = wpabuf_alloc(tot_len);
if (data->inbuf == NULL) {
wpa_printf(MSG_INFO, "Out of memory to buffer "
"fragments!");
return NULL;
}
pos += sizeof(u16);
len -= sizeof(u16);
}
/*
* buffer and ACK the fragment
*/
if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
data->in_frag_pos += len;
if (data->in_frag_pos > wpabuf_size(data->inbuf)) {
wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack "
"detected (%d vs. %d)!",
(int) data->in_frag_pos,
(int) wpabuf_len(data->inbuf));
wpabuf_free(data->inbuf);
data->in_frag_pos = 0;
return NULL;
}
wpabuf_put_data(data->inbuf, pos, len);
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE,
EAP_CODE_RESPONSE, eap_get_id(reqData));
if (resp != NULL)
wpabuf_put_u8(resp, (EAP_PWD_GET_EXCHANGE(lm_exch)));
wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a %d byte fragment",
(int) len);
return resp;
}
/*
* we're buffering and this is the last fragment
*/
if (data->in_frag_pos) {
wpabuf_put_data(data->inbuf, pos, len);
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
(int) len);
data->in_frag_pos += len;
pos = wpabuf_head_u8(data->inbuf);
len = data->in_frag_pos;
}
wpa_printf(MSG_DEBUG, "EAP-pwd: processing frame: exch %d, len %d",
EAP_PWD_GET_EXCHANGE(lm_exch), (int) len);
switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
case EAP_PWD_OPCODE_ID_EXCH:
eap_pwd_perform_id_exchange(sm, data, ret, reqData,
pos, len);
break;
case EAP_PWD_OPCODE_COMMIT_EXCH:
resp = eap_pwd_perform_commit_exchange(sm, data, ret, reqData,
pos + 1, len - 1);
case EAP_PWD_OPCODE_COMMIT_EXCH:
eap_pwd_perform_commit_exchange(sm, data, ret, reqData,
pos, len);
break;
case EAP_PWD_OPCODE_CONFIRM_EXCH:
resp = eap_pwd_perform_confirm_exchange(sm, data, ret, reqData,
pos + 1, len - 1);
case EAP_PWD_OPCODE_CONFIRM_EXCH:
eap_pwd_perform_confirm_exchange(sm, data, ret, reqData,
pos, len);
break;
default:
default:
wpa_printf(MSG_INFO, "EAP-pwd: Ignoring message with unknown "
"opcode %d", exch);
"opcode %d", lm_exch);
break;
}
/*
* if we buffered the just processed input now's the time to free it
*/
if (data->in_frag_pos) {
wpabuf_free(data->inbuf);
data->in_frag_pos = 0;
}
if (data->outbuf == NULL)
return NULL; /* generic failure */
/*
* we have output! Do we need to fragment it?
*/
len = wpabuf_len(data->outbuf);
if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, data->mtu,
EAP_CODE_RESPONSE, eap_get_id(reqData));
/*
* if so it's the first so include a length field
*/
EAP_PWD_SET_LENGTH_BIT(lm_exch);
EAP_PWD_SET_MORE_BIT(lm_exch);
tot_len = len;
/*
* keep the packet at the MTU
*/
len = data->mtu - EAP_PWD_HDR_SIZE - sizeof(u16);
wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, total "
"length = %d", tot_len);
} else {
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE + len,
EAP_CODE_RESPONSE, eap_get_id(reqData));
}
if (resp == NULL)
return NULL;
wpabuf_put_u8(resp, lm_exch);
if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
wpabuf_put_be16(resp, tot_len);
data->out_frag_pos += len;
}
buf = wpabuf_head_u8(data->outbuf);
wpabuf_put_data(resp, buf, len);
/*
* if we're not fragmenting then there's no need to carry this around
*/
if (data->out_frag_pos == 0)
wpabuf_free(data->outbuf);
return resp;
}

311
src/eap_server/eap_server_pwd.c
View File

@ -33,6 +33,12 @@ struct eap_pwd_data {
u16 group_num;
EAP_PWD_group *grp;
struct wpabuf *inbuf;
size_t in_frag_pos;
struct wpabuf *outbuf;
size_t out_frag_pos;
size_t mtu;
BIGNUM *k;
BIGNUM *private_value;
BIGNUM *peer_scalar;
@ -120,6 +126,10 @@ static void * eap_pwd_init(struct eap_sm *sm)
return NULL;
}
data->in_frag_pos = data->out_frag_pos = 0;
data->inbuf = data->outbuf = NULL;
data->mtu = 1020; /* default from RFC 5931, make it configurable! */
return data;
}
@ -149,44 +159,48 @@ static void eap_pwd_reset(struct eap_sm *sm, void *priv)
}
static struct wpabuf *
eap_pwd_build_id_req(struct eap_sm *sm, struct eap_pwd_data *data, u8 id)
static void eap_pwd_build_id_req(struct eap_sm *sm, struct eap_pwd_data *data,
u8 id)
{
struct wpabuf *req;
wpa_printf(MSG_DEBUG, "EAP-pwd: ID/Request");
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
1 + sizeof(struct eap_pwd_id) +
data->id_server_len,
EAP_CODE_REQUEST, id);
if (req == NULL) {
/*
* if we're fragmenting then we already have an id request, just return
*/
if (data->out_frag_pos)
return;
data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) +
data->id_server_len);
if (data->outbuf == NULL) {
eap_pwd_state(data, FAILURE);
return NULL;
return;
}
/* an lfsr is good enough to generate unpredictable tokens */
data->token = os_random();
wpabuf_put_u8(req, EAP_PWD_OPCODE_ID_EXCH);
wpabuf_put_be16(req, data->group_num);
wpabuf_put_u8(req, EAP_PWD_DEFAULT_RAND_FUNC);
wpabuf_put_u8(req, EAP_PWD_DEFAULT_PRF);
wpabuf_put_data(req, &data->token, sizeof(data->token));
wpabuf_put_u8(req, EAP_PWD_PREP_NONE);
wpabuf_put_data(req, data->id_server, data->id_server_len);
return req;
wpabuf_put_be16(data->outbuf, data->group_num);
wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC);
wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF);
wpabuf_put_data(data->outbuf, &data->token, sizeof(data->token));
wpabuf_put_u8(data->outbuf, EAP_PWD_PREP_NONE);
wpabuf_put_data(data->outbuf, data->id_server, data->id_server_len);
}
static struct wpabuf *
eap_pwd_build_commit_req(struct eap_sm *sm, struct eap_pwd_data *data, u8 id)
static void eap_pwd_build_commit_req(struct eap_sm *sm,
struct eap_pwd_data *data, u8 id)
{
struct wpabuf *req = NULL;
BIGNUM *mask = NULL, *x = NULL, *y = NULL;
u8 *scalar = NULL, *element = NULL;
u16 offset;
wpa_printf(MSG_DEBUG, "EAP-pwd: Commit/Request");
/*
* if we're fragmenting then we already have an commit request, just
* return
*/
if (data->out_frag_pos)
return;
if (((data->private_value = BN_new()) == NULL) ||
((data->my_element = EC_POINT_new(data->grp->group)) == NULL) ||
@ -256,34 +270,29 @@ eap_pwd_build_commit_req(struct eap_sm *sm, struct eap_pwd_data *data, u8 id)
offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
1 + (2 * BN_num_bytes(data->grp->prime)) +
BN_num_bytes(data->grp->order),
EAP_CODE_REQUEST, id);
if (req == NULL)
data->outbuf = wpabuf_alloc(2 * BN_num_bytes(data->grp->prime) +
BN_num_bytes(data->grp->order));
if (data->outbuf == NULL)
goto fin;
wpabuf_put_u8(req, EAP_PWD_OPCODE_COMMIT_EXCH);
/* We send the element as (x,y) followed by the scalar */
wpabuf_put_data(req, element, (2 * BN_num_bytes(data->grp->prime)));
wpabuf_put_data(req, scalar, BN_num_bytes(data->grp->order));
wpabuf_put_data(data->outbuf, element,
2 * BN_num_bytes(data->grp->prime));
wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order));
fin:
os_free(scalar);
os_free(element);
BN_free(x);
BN_free(y);
if (req == NULL)
if (data->outbuf == NULL)
eap_pwd_state(data, FAILURE);
return req;
}
static struct wpabuf *
eap_pwd_build_confirm_req(struct eap_sm *sm, struct eap_pwd_data *data, u8 id)
static void eap_pwd_build_confirm_req(struct eap_sm *sm,
struct eap_pwd_data *data, u8 id)
{
struct wpabuf *req = NULL;
BIGNUM *x = NULL, *y = NULL;
HMAC_CTX ctx;
u8 conf[SHA256_DIGEST_LENGTH], *cruft = NULL, *ptr;
@ -291,6 +300,12 @@ eap_pwd_build_confirm_req(struct eap_sm *sm, struct eap_pwd_data *data, u8 id)
int offset;
wpa_printf(MSG_DEBUG, "EAP-pwd: Confirm/Request");
/*
* if we're fragmenting then we already have an confirm request, just
* return
*/
if (data->out_frag_pos)
return;
/* Each component of the cruft will be at most as big as the prime */
if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
@ -383,23 +398,20 @@ eap_pwd_build_confirm_req(struct eap_sm *sm, struct eap_pwd_data *data, u8 id)
H_Final(&ctx, conf);
os_memcpy(data->my_confirm, conf, SHA256_DIGEST_LENGTH);
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
1 + SHA256_DIGEST_LENGTH,
EAP_CODE_REQUEST, id);
if (req == NULL)
data->outbuf = wpabuf_alloc(SHA256_DIGEST_LENGTH);
if (data->outbuf == NULL)
goto fin;
wpabuf_put_u8(req, EAP_PWD_OPCODE_CONFIRM_EXCH);
wpabuf_put_data(req, conf, SHA256_DIGEST_LENGTH);
wpabuf_put_data(data->outbuf, conf, SHA256_DIGEST_LENGTH);
fin:
os_free(cruft);
BN_free(x);
BN_free(y);
if (req == NULL)
if (data->outbuf == NULL)
eap_pwd_state(data, FAILURE);
return req;
return;
}
@ -407,21 +419,119 @@ static struct wpabuf *
eap_pwd_build_req(struct eap_sm *sm, void *priv, u8 id)
{
struct eap_pwd_data *data = priv;
struct wpabuf *req;
u8 lm_exch;
const u8 *buf;
u16 totlen = 0;
size_t len;
/*
* if we're buffering response fragments then just ACK
*/
if (data->in_frag_pos) {
wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a fragment!!");
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE, EAP_CODE_REQUEST, id);
if (req == NULL) {
eap_pwd_state(data, FAILURE);
return NULL;
}
switch (data->state) {
case PWD_ID_Req:
wpabuf_put_u8(req, EAP_PWD_OPCODE_ID_EXCH);
break;
case PWD_Commit_Req:
wpabuf_put_u8(req, EAP_PWD_OPCODE_COMMIT_EXCH);
break;
case PWD_Confirm_Req:
wpabuf_put_u8(req, EAP_PWD_OPCODE_CONFIRM_EXCH);
break;
default:
eap_pwd_state(data, FAILURE); /* just to be sure */
wpabuf_free(req);
return NULL;
}
return req;
}
/*
* build the data portion of a request
*/
switch (data->state) {
case PWD_ID_Req:
return eap_pwd_build_id_req(sm, data, id);
case PWD_Commit_Req:
return eap_pwd_build_commit_req(sm, data, id);
case PWD_Confirm_Req:
return eap_pwd_build_confirm_req(sm, data, id);
default:
case PWD_ID_Req:
eap_pwd_build_id_req(sm, data, id);
lm_exch = EAP_PWD_OPCODE_ID_EXCH;
break;
case PWD_Commit_Req:
eap_pwd_build_commit_req(sm, data, id);
lm_exch = EAP_PWD_OPCODE_COMMIT_EXCH;
break;
case PWD_Confirm_Req:
eap_pwd_build_confirm_req(sm, data, id);
lm_exch = EAP_PWD_OPCODE_CONFIRM_EXCH;
break;
default:
wpa_printf(MSG_INFO, "EAP-pwd: Unknown state %d in build_req",
data->state);
eap_pwd_state(data, FAILURE);
lm_exch = 0; /* hush now, sweet compiler */
break;
}
return NULL;
if (data->state == FAILURE)
return NULL;
/*
* determine whether that data needs to be fragmented
*/
len = wpabuf_len(data->outbuf) - data->out_frag_pos;
if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
len = data->mtu - EAP_PWD_HDR_SIZE;
EAP_PWD_SET_MORE_BIT(lm_exch);
/*
* if this is the first fragment, need to set the M bit
* and add the total length to the eap_pwd_hdr
*/
if (data->out_frag_pos == 0) {
EAP_PWD_SET_LENGTH_BIT(lm_exch);
totlen = wpabuf_len(data->outbuf) +
EAP_PWD_HDR_SIZE + sizeof(u16);
len -= sizeof(u16);
wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, "
"total length = %d", totlen);
}
wpa_printf(MSG_DEBUG, "EAP-pwd: Send a %d byte fragment",
(int) len);
}
/*
* alloc an eap request and populate it with the data
*/
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE + len +
(totlen ? sizeof(u16) : 0),
EAP_CODE_REQUEST, id);
if (req == NULL) {
eap_pwd_state(data, FAILURE);
return NULL;
}
wpabuf_put_u8(req, lm_exch);
if (EAP_PWD_GET_LENGTH_BIT(lm_exch))
wpabuf_put_be16(req, totlen);
buf = wpabuf_head_u8(data->outbuf);
wpabuf_put_data(req, buf + data->out_frag_pos, len);
data->out_frag_pos += len;
/*
* either not fragged or last fragment, either way free up the data
*/
if (data->out_frag_pos >= wpabuf_len(data->outbuf)) {
wpabuf_free(data->outbuf);
data->out_frag_pos = 0;
}
return req;
}
@ -438,17 +548,19 @@ static Boolean eap_pwd_check(struct eap_sm *sm, void *priv,
return TRUE;
}
wpa_printf(MSG_DEBUG, "EAP-pwd: Received frame: opcode=%d", *pos);
wpa_printf(MSG_DEBUG, "EAP-pwd: Received frame: exch = %d, len = %d",
EAP_PWD_GET_EXCHANGE(*pos), (int) len);
if (data->state == PWD_ID_Req && *pos == EAP_PWD_OPCODE_ID_EXCH)
if (data->state == PWD_ID_Req &&
((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_ID_EXCH))
return FALSE;
if (data->state == PWD_Commit_Req &&
*pos == EAP_PWD_OPCODE_COMMIT_EXCH)
((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_COMMIT_EXCH))
return FALSE;
if (data->state == PWD_Confirm_Req &&
*pos == EAP_PWD_OPCODE_CONFIRM_EXCH)
((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_CONFIRM_EXCH))
return FALSE;
wpa_printf(MSG_INFO, "EAP-pwd: Unexpected opcode=%d in state=%d",
@ -747,7 +859,8 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
struct eap_pwd_data *data = priv;
const u8 *pos;
size_t len;
u8 exch;
u8 lm_exch;
u16 tot_len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
if ((pos == NULL) || (len < 1)) {
@ -757,18 +870,90 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
return;
}
exch = *pos & 0x3f;
switch (exch) {
lm_exch = *pos;
pos++; /* skip over the bits and the exch */
len--;
/*
* if we're fragmenting then this should be an ACK with no data,
* just return and continue fragmenting in the "build" section above
*/
if (data->out_frag_pos) {
if (len > 1)
wpa_printf(MSG_INFO, "EAP-pwd: Bad response! "
"Fragmenting but not an ACK");
else
wpa_printf(MSG_DEBUG, "EAP-pwd: received ACK from "
"peer");
return;
}
/*
* if we're receiving fragmented packets then we need to buffer...
*
* the first fragment has a total length
*/
if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
tot_len = WPA_GET_BE16(pos);
wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments, total "
"length = %d", tot_len);
data->inbuf = wpabuf_alloc(tot_len);
if (data->inbuf == NULL) {
wpa_printf(MSG_INFO, "EAP-pwd: Out of memory to "
"buffer fragments!");
return;
}
pos += sizeof(u16);
len -= sizeof(u16);
}
/*
* the first and all intermediate fragments have the M bit set
*/
if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
"attack detected! (%d+%d > %d)",
(int) data->in_frag_pos, (int) len,
(int) wpabuf_size(data->inbuf));
eap_pwd_state(data, FAILURE);
return;
}
wpabuf_put_data(data->inbuf, pos, len);
data->in_frag_pos += len;
wpa_printf(MSG_DEBUG, "EAP-pwd: Got a %d byte fragment",
(int) len);
return;
}
/*
* last fragment won't have the M bit set (but we're obviously
* buffering fragments so that's how we know it's the last)
*/
if (data->in_frag_pos) {
wpabuf_put_data(data->inbuf, pos, len);
data->in_frag_pos += len;
pos = wpabuf_head_u8(data->inbuf);
len = data->in_frag_pos;
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
(int) len);
}
switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
case EAP_PWD_OPCODE_ID_EXCH:
eap_pwd_process_id_resp(sm, data, pos + 1, len - 1);
eap_pwd_process_id_resp(sm, data, pos, len);
break;
case EAP_PWD_OPCODE_COMMIT_EXCH:
eap_pwd_process_commit_resp(sm, data, pos + 1, len - 1);
eap_pwd_process_commit_resp(sm, data, pos, len);
break;
case EAP_PWD_OPCODE_CONFIRM_EXCH:
eap_pwd_process_confirm_resp(sm, data, pos + 1, len - 1);
case EAP_PWD_OPCODE_CONFIRM_EXCH:
eap_pwd_process_confirm_resp(sm, data, pos, len);
break;
}
/*
* if we had been buffering fragments, here's a great place
* to clean up
*/
if (data->in_frag_pos) {
wpabuf_free(data->inbuf);
data->in_frag_pos = 0;
}
}