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Simplify tls_construct_server_key_exchange 

Use negotiated signature algorithm and certificate index in
tls_construct_key_exchange instead of recalculating it.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2623)
This commit is contained in:
Dr. Stephen Henson 2017-02-13 18:07:00 +00:00
parent f365a3e2e5
commit f695571e10
1 changed files with 61 additions and 75 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

136
ssl/statem/statem_srvr.c
View File

@ -1996,8 +1996,7 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
size_t encodedlen = 0;
int curve_id = 0;
#endif
EVP_PKEY *pkey;
const EVP_MD *md = NULL;
const SIGALG_LOOKUP *lu = s->s3->tmp.sigalg;
int al = SSL_AD_INTERNAL_ERROR, i;
unsigned long type;
const BIGNUM *r[4];
@ -2154,16 +2153,12 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
goto f_err;
}
if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aSRP))
&& !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) {
if (s->s3->tmp.cert_idx == -1 || s->s3->tmp.sigalg == NULL) {
al = SSL_AD_DECODE_ERROR;
goto f_err;
}
pkey = s->cert->pkeys[s->s3->tmp.cert_idx].privatekey;
md = ssl_md(s->s3->tmp.sigalg->hash_idx);
} else {
pkey = NULL;
if (((s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aSRP)) != 0)
|| ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) != 0) {
lu = NULL;
} else if (lu == NULL) {
al = SSL_AD_DECODE_ERROR;
goto f_err;
}
#ifndef OPENSSL_NO_PSK
@ -2253,75 +2248,66 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
#endif
/* not anonymous */
if (pkey != NULL) {
if (lu != NULL) {
EVP_PKEY *pkey = s->cert->pkeys[s->s3->tmp.cert_idx].privatekey;
const EVP_MD *md = ssl_md(lu->hash_idx);
unsigned char *sigbytes1, *sigbytes2;
size_t siglen;
if (pkey == NULL || md == NULL) {
/* Should never happen */
al = SSL_AD_INTERNAL_ERROR;
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
/*
* n is the length of the params, they start at &(d[4]) and p
* points to the space at the end.
*/
if (md) {
unsigned char *sigbytes1, *sigbytes2;
size_t siglen;
int ispss = 0;
/* Get length of the parameters we have written above */
if (!WPACKET_get_length(pkt, &paramlen)) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
/* send signature algorithm */
if (SSL_USE_SIGALGS(s)) {
if (!tls12_get_sigandhash(s, pkt, pkey, md, &ispss)) {
/* Should never happen */
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
}
#ifdef SSL_DEBUG
fprintf(stderr, "Using hash %s\n", EVP_MD_name(md));
#endif
/*
* Create the signature. We don't know the actual length of the sig
* until after we've created it, so we reserve enough bytes for it
* up front, and then properly allocate them in the WPACKET
* afterwards.
*/
siglen = EVP_PKEY_size(pkey);
if (!WPACKET_sub_reserve_bytes_u16(pkt, siglen, &sigbytes1)
|| EVP_DigestSignInit(md_ctx, &pctx, md, NULL, pkey) <= 0) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
if (ispss) {
if (EVP_PKEY_CTX_set_rsa_padding(pctx,
RSA_PKCS1_PSS_PADDING) <= 0
|| EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST) <= 0) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_EVP_LIB);
goto f_err;
}
}
if (EVP_DigestSignUpdate(md_ctx, &(s->s3->client_random[0]),
SSL3_RANDOM_SIZE) <= 0
|| EVP_DigestSignUpdate(md_ctx, &(s->s3->server_random[0]),
SSL3_RANDOM_SIZE) <= 0
|| EVP_DigestSignUpdate(md_ctx,
s->init_buf->data + paramoffset,
paramlen) <= 0
|| EVP_DigestSignFinal(md_ctx, sigbytes1, &siglen) <= 0
|| !WPACKET_sub_allocate_bytes_u16(pkt, siglen, &sigbytes2)
|| sigbytes1 != sigbytes2) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
} else {
/* Is this error check actually needed? */
al = SSL_AD_HANDSHAKE_FAILURE;
/* Get length of the parameters we have written above */
if (!WPACKET_get_length(pkt, &paramlen)) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
SSL_R_UNKNOWN_PKEY_TYPE);
ERR_R_INTERNAL_ERROR);
goto f_err;
}
/* send signature algorithm */
if (SSL_USE_SIGALGS(s) && !WPACKET_put_bytes_u16(pkt, lu->sigalg))
return 0;
/*
* Create the signature. We don't know the actual length of the sig
* until after we've created it, so we reserve enough bytes for it
* up front, and then properly allocate them in the WPACKET
* afterwards.
*/
siglen = EVP_PKEY_size(pkey);
if (!WPACKET_sub_reserve_bytes_u16(pkt, siglen, &sigbytes1)
|| EVP_DigestSignInit(md_ctx, &pctx, md, NULL, pkey) <= 0) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
if (lu->sig == EVP_PKEY_RSA_PSS) {
if (EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) <= 0
|| EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, RSA_PSS_SALTLEN_DIGEST) <= 0) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_EVP_LIB);
goto f_err;
}
}
if (EVP_DigestSignUpdate(md_ctx, &(s->s3->client_random[0]),
SSL3_RANDOM_SIZE) <= 0
|| EVP_DigestSignUpdate(md_ctx, &(s->s3->server_random[0]),
SSL3_RANDOM_SIZE) <= 0
|| EVP_DigestSignUpdate(md_ctx,
s->init_buf->data + paramoffset,
paramlen) <= 0
|| EVP_DigestSignFinal(md_ctx, sigbytes1, &siglen) <= 0
|| !WPACKET_sub_allocate_bytes_u16(pkt, siglen, &sigbytes2)
|| sigbytes1 != sigbytes2) {
SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
ERR_R_INTERNAL_ERROR);
goto f_err;
}
}