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PACKET: simplify ServerKeyExchange parsing

Browse source 
Reviewed-by: Matt Caswell <matt@openssl.org>
This commit is contained in:
Emilia Kasper 2015-10-02 14:40:30 +02:00
parent 28dc5d1963
commit 329428708d
4 changed files with 101 additions and 200 deletions
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1
include/openssl/ssl.h
View file

@ -2115,6 +2115,7 @@ void ERR_load_SSL_strings(void);
# define SSL_R_BAD_DH_PUB_KEY_VALUE 393
# define SSL_R_BAD_DH_P_LENGTH 110
# define SSL_R_BAD_DH_P_VALUE 395
# define SSL_R_BAD_DH_VALUE 102
# define SSL_R_BAD_DIGEST_LENGTH 111
# define SSL_R_BAD_DSA_SIGNATURE 112
# define SSL_R_BAD_ECC_CERT 304

2
ssl/packet_locl.h
View file

@ -418,6 +418,8 @@ __owur static inline int PACKET_memdup(const PACKET *pkt, unsigned char **data,
__owur static inline int PACKET_strndup(const PACKET *pkt, char **data)
{
OPENSSL_free(*data);
/* This will succeed on an empty packet, unless pkt->curr == NULL. */
*data = BUF_strndup((const char*)pkt->curr, PACKET_remaining(pkt));
return (*data != NULL);
}

297
ssl/s3_clnt.c
View file

@ -1434,7 +1434,6 @@ int ssl3_get_key_exchange(SSL *s)
#endif
EVP_MD_CTX md_ctx;
int al, j, verify_ret, ok;
unsigned int i;
long n, alg_k, alg_a;
EVP_PKEY *pkey = NULL;
const EVP_MD *md = NULL;
@ -1449,11 +1448,8 @@ int ssl3_get_key_exchange(SSL *s)
BN_CTX *bn_ctx = NULL;
EC_POINT *srvr_ecpoint = NULL;
int curve_nid = 0;
unsigned int encoded_pt_len = 0;
#endif
PACKET pkt, save_param_start;
unsigned char *data, *param;
size_t param_len;
PACKET pkt, save_param_start, signature;
EVP_MD_CTX_init(&md_ctx);
@ -1512,9 +1508,9 @@ int ssl3_get_key_exchange(SSL *s)
#ifndef OPENSSL_NO_PSK
/* PSK ciphersuites are preceded by an identity hint */
if (alg_k & SSL_PSK) {
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
PACKET psk_identity_hint;
if (!PACKET_get_length_prefixed_2(&pkt, &psk_identity_hint)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
@ -1524,34 +1520,17 @@ int ssl3_get_key_exchange(SSL *s)
* a PSK identity hint can be as long as the maximum length of a PSK
* identity.
*/
if (i > PSK_MAX_IDENTITY_LEN) {
if (PACKET_remaining(&psk_identity_hint) > PSK_MAX_IDENTITY_LEN) {
al = SSL_AD_HANDSHAKE_FAILURE;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_DATA_LENGTH_TOO_LONG);
goto f_err;
}
if (PACKET_remaining(&pkt) < i) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,
SSL_R_BAD_PSK_IDENTITY_HINT_LENGTH);
if (!PACKET_strndup(&psk_identity_hint,
&s->session->psk_identity_hint)) {
al = SSL_AD_INTERNAL_ERROR;
goto f_err;
}
OPENSSL_free(s->session->psk_identity_hint);
if (i != 0) {
unsigned char *hint = NULL;
if (!PACKET_get_bytes(&pkt, &hint, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
s->session->psk_identity_hint = BUF_strndup((char *)hint, i);
if (s->session->psk_identity_hint == NULL) {
al = SSL_AD_HANDSHAKE_FAILURE;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
goto f_err;
}
} else {
s->session->psk_identity_hint = NULL;
}
}
/* Nothing else to do for plain PSK or RSAPSK */
@ -1560,62 +1539,27 @@ int ssl3_get_key_exchange(SSL *s)
#endif /* !OPENSSL_NO_PSK */
#ifndef OPENSSL_NO_SRP
if (alg_k & SSL_kSRP) {
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
PACKET prime, generator, salt, server_pub;
if (!PACKET_get_length_prefixed_2(&pkt, &prime)
|| !PACKET_get_length_prefixed_2(&pkt, &generator)
|| !PACKET_get_length_prefixed_1(&pkt, &salt)
|| !PACKET_get_length_prefixed_2(&pkt, &server_pub)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_SRP_N_LENGTH);
goto f_err;
}
if ((s->srp_ctx.N = BN_bin2bn(data, i, NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_SRP_G_LENGTH);
goto f_err;
}
if ((s->srp_ctx.g = BN_bin2bn(data, i, NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (!PACKET_get_1(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_SRP_S_LENGTH);
goto f_err;
}
if ((s->srp_ctx.s = BN_bin2bn(data, i, NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_SRP_B_LENGTH);
goto f_err;
}
if ((s->srp_ctx.B = BN_bin2bn(data, i, NULL)) == NULL) {
if ((s->srp_ctx.N =
BN_bin2bn(PACKET_data(&prime),
PACKET_remaining(&prime), NULL)) == NULL
|| (s->srp_ctx.g =
BN_bin2bn(PACKET_data(&generator),
PACKET_remaining(&generator), NULL)) == NULL
|| (s->srp_ctx.s =
BN_bin2bn(PACKET_data(&salt),
PACKET_remaining(&salt), NULL)) == NULL
|| (s->srp_ctx.B =
BN_bin2bn(PACKET_data(&server_pub),
PACKET_remaining(&server_pub), NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
@ -1632,43 +1576,29 @@ int ssl3_get_key_exchange(SSL *s)
#endif /* !OPENSSL_NO_SRP */
#ifndef OPENSSL_NO_RSA
if (alg_k & SSL_kRSA) {
PACKET mod, exp;
/* Temporary RSA keys only allowed in export ciphersuites */
if (!SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
if (!PACKET_get_length_prefixed_2(&pkt, &mod)
|| !PACKET_get_length_prefixed_2(&pkt, &exp)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
if ((rsa = RSA_new()) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_RSA_MODULUS_LENGTH);
goto f_err;
}
if ((rsa->n = BN_bin2bn(data, i, rsa->n)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_RSA_E_LENGTH);
goto f_err;
}
if ((rsa->e = BN_bin2bn(data, i, rsa->e)) == NULL) {
if ((rsa->n = BN_bin2bn(PACKET_data(&mod), PACKET_remaining(&mod),
rsa->n)) == NULL
|| (rsa->e = BN_bin2bn(PACKET_data(&exp), PACKET_remaining(&exp),
rsa->e)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
@ -1695,68 +1625,33 @@ int ssl3_get_key_exchange(SSL *s)
#endif
#ifndef OPENSSL_NO_DH
else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
PACKET prime, generator, pub_key;
if (!PACKET_get_length_prefixed_2(&pkt, &prime)
|| !PACKET_get_length_prefixed_2(&pkt, &generator)
|| !PACKET_get_length_prefixed_2(&pkt, &pub_key)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
if ((dh = DH_new()) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_DH_LIB);
goto err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_P_LENGTH);
goto f_err;
}
if ((dh->p = BN_bin2bn(data, i, NULL)) == NULL) {
if ((dh->p = BN_bin2bn(PACKET_data(&prime),
PACKET_remaining(&prime), NULL)) == NULL
|| (dh->g = BN_bin2bn(PACKET_data(&generator),
PACKET_remaining(&generator), NULL)) == NULL
|| (dh->pub_key =
BN_bin2bn(PACKET_data(&pub_key),
PACKET_remaining(&pub_key), NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(dh->p)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_P_VALUE);
goto f_err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_G_LENGTH);
goto f_err;
}
if ((dh->g = BN_bin2bn(data, i, NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(dh->g)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_G_VALUE);
goto f_err;
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_PUB_KEY_LENGTH);
goto f_err;
}
if ((dh->pub_key = BN_bin2bn(data, i, NULL)) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(dh->pub_key)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_PUB_KEY_VALUE);
if (BN_is_zero(dh->p) || BN_is_zero(dh->g) || BN_is_zero(dh->pub_key)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_DH_VALUE);
goto f_err;
}
@ -1778,6 +1673,8 @@ int ssl3_get_key_exchange(SSL *s)
else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
EC_GROUP *ngroup;
const EC_GROUP *group;
PACKET encoded_pt;
unsigned char *ecparams;
if ((ecdh = EC_KEY_new()) == NULL) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
@ -1786,15 +1683,10 @@ int ssl3_get_key_exchange(SSL *s)
/*
* Extract elliptic curve parameters and the server's ephemeral ECDH
* public key. Keep accumulating lengths of various components in
* param_len and make sure it never exceeds n.
*/
/*
* XXX: For now we only support named (not generic) curves and the
* public key. For now we only support named (not generic) curves and
* ECParameters in this case is just three bytes.
*/
if (!PACKET_get_bytes(&pkt, &data, 3)) {
if (!PACKET_get_bytes(&pkt, &ecparams, 3)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
@ -1802,12 +1694,12 @@ int ssl3_get_key_exchange(SSL *s)
* Check curve is one of our preferences, if not server has sent an
* invalid curve. ECParameters is 3 bytes.
*/
if (!tls1_check_curve(s, data, 3)) {
if (!tls1_check_curve(s, ecparams, 3)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_WRONG_CURVE);
goto f_err;
}
if ((curve_nid = tls1_ec_curve_id2nid(*(data + 2))) == 0) {
if ((curve_nid = tls1_ec_curve_id2nid(*(ecparams + 2))) == 0) {
al = SSL_AD_INTERNAL_ERROR;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,
SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
@ -1842,14 +1734,13 @@ int ssl3_get_key_exchange(SSL *s)
goto err;
}
if (!PACKET_get_1(&pkt, &encoded_pt_len)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
if (!PACKET_get_length_prefixed_1(&pkt, &encoded_pt)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
if (!PACKET_get_bytes(&pkt, &data, encoded_pt_len) ||
(EC_POINT_oct2point(group, srvr_ecpoint,
data, encoded_pt_len, bn_ctx) == 0)) {
if (EC_POINT_oct2point(group, srvr_ecpoint, PACKET_data(&encoded_pt),
PACKET_remaining(&encoded_pt), bn_ctx) == 0) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_ECPOINT);
goto f_err;
}
@ -1883,21 +1774,29 @@ int ssl3_get_key_exchange(SSL *s)
}
#endif /* !OPENSSL_NO_EC */
/*
* |pkt| now points to the beginning of the signature, so the difference
* equals the length of the parameters.
*/
param_len = PACKET_remaining(&save_param_start) - PACKET_remaining(&pkt);
/* if it was signed, check the signature */
if (pkey != NULL) {
PACKET params;
/*
* |pkt| now points to the beginning of the signature, so the difference
* equals the length of the parameters.
*/
if (!PACKET_get_sub_packet(&save_param_start, &params,
PACKET_remaining(&save_param_start) -
PACKET_remaining(&pkt))) {
al = SSL_AD_INTERNAL_ERROR;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
goto f_err;
}
if (SSL_USE_SIGALGS(s)) {
unsigned char *sigalgs;
int rv;
if (!PACKET_get_bytes(&pkt, &data, 2)) {
if (!PACKET_get_bytes(&pkt, &sigalgs, 2)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
rv = tls12_check_peer_sigalg(&md, s, data, pkey);
rv = tls12_check_peer_sigalg(&md, s, sigalgs, pkey);
if (rv == -1)
goto err;
else if (rv == 0) {
@ -1906,11 +1805,13 @@ int ssl3_get_key_exchange(SSL *s)
#ifdef SSL_DEBUG
fprintf(stderr, "USING TLSv1.2 HASH %s\n", EVP_MD_name(md));
#endif
} else
} else {
md = EVP_sha1();
}
if (!PACKET_get_net_2(&pkt, &i)) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
if (!PACKET_get_length_prefixed_2(&pkt, &signature)
|| PACKET_remaining(&pkt) != 0) {
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
goto f_err;
}
j = EVP_PKEY_size(pkey);
@ -1922,19 +1823,11 @@ int ssl3_get_key_exchange(SSL *s)
/*
* Check signature length
*/
if (i > (unsigned int)j
|| !PACKET_get_bytes(&pkt, &data, i)
|| PACKET_remaining(&pkt) != 0) {
if (PACKET_remaining(&signature) > (size_t)j) {
/* wrong packet length */
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_WRONG_SIGNATURE_LENGTH);
goto f_err;
}
pkt = save_param_start;
if (!PACKET_get_bytes(&pkt, &param, param_len)) {
al = SSL_AD_INTERNAL_ERROR;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
goto f_err;
}
#ifndef OPENSSL_NO_RSA
if (pkey->type == EVP_PKEY_RSA && !SSL_USE_SIGALGS(s)) {
int num;
@ -1950,13 +1843,15 @@ int ssl3_get_key_exchange(SSL *s)
SSL3_RANDOM_SIZE);
EVP_DigestUpdate(&md_ctx, &(s->s3->server_random[0]),
SSL3_RANDOM_SIZE);
EVP_DigestUpdate(&md_ctx, param, param_len);
EVP_DigestUpdate(&md_ctx, PACKET_data(&params),
PACKET_remaining(&params));
EVP_DigestFinal_ex(&md_ctx, q, &size);
q += size;
j += size;
}
verify_ret =
RSA_verify(NID_md5_sha1, md_buf, j, data, i, pkey->pkey.rsa);
RSA_verify(NID_md5_sha1, md_buf, j, PACKET_data(&signature),
PACKET_remaining(&signature), pkey->pkey.rsa);
if (verify_ret < 0) {
al = SSL_AD_DECRYPT_ERROR;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_RSA_DECRYPT);
@ -1976,8 +1871,10 @@ int ssl3_get_key_exchange(SSL *s)
SSL3_RANDOM_SIZE);
EVP_VerifyUpdate(&md_ctx, &(s->s3->server_random[0]),
SSL3_RANDOM_SIZE);
EVP_VerifyUpdate(&md_ctx, param, param_len);
if (EVP_VerifyFinal(&md_ctx, data, (int)i, pkey) <= 0) {
EVP_VerifyUpdate(&md_ctx, PACKET_data(&params),
PACKET_remaining(&params));
if (EVP_VerifyFinal(&md_ctx, PACKET_data(&signature),
PACKET_remaining(&signature), pkey) <= 0) {
/* bad signature */
al = SSL_AD_DECRYPT_ERROR;
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_SIGNATURE);

1
ssl/ssl_err.c
View file

@ -351,6 +351,7 @@ static ERR_STRING_DATA SSL_str_reasons[] = {
{ERR_REASON(SSL_R_BAD_DH_PUB_KEY_VALUE), "bad dh pub key value"},
{ERR_REASON(SSL_R_BAD_DH_P_LENGTH), "bad dh p length"},
{ERR_REASON(SSL_R_BAD_DH_P_VALUE), "bad dh p value"},
{ERR_REASON(SSL_R_BAD_DH_VALUE), "bad dh value"},
{ERR_REASON(SSL_R_BAD_DIGEST_LENGTH), "bad digest length"},
{ERR_REASON(SSL_R_BAD_DSA_SIGNATURE), "bad dsa signature"},
{ERR_REASON(SSL_R_BAD_ECC_CERT), "bad ecc cert"},