/*
* Given a |secret|; a |label| of length |labellen|; and a |hash| of the
* handshake messages, derive a new secret |outlen| bytes long and store it in
* the location pointed to be |out|. The |hash| value may be NULL. Returns 1 on
* success 0 on failure.
*/
static int tls13_hkdf_expand(SSL *s, const unsigned char *secret,
const unsigned char *label, size_t labellen,
const unsigned char *hash,
unsigned char *out, size_t outlen)
{
const unsigned char label_prefix[] = "TLS 1.3, ";
const EVP_MD *md = ssl_handshake_md(s);
EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
int ret;
size_t hkdflabellen;
size_t hashlen;
/*
* 2 bytes for length of whole HkdfLabel + 1 byte for length of combined
* prefix and label + bytes for the label itself + bytes for the hash
*/
unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
+ sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
+ EVP_MAX_MD_SIZE];
WPACKET pkt;
if (pctx == NULL)
return 0;
hashlen = EVP_MD_size(md);
if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
|| !WPACKET_put_bytes_u16(&pkt, outlen)
|| !WPACKET_start_sub_packet_u8(&pkt)
|| !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
|| !WPACKET_memcpy(&pkt, label, labellen)
|| !WPACKET_close(&pkt)
|| !WPACKET_sub_memcpy_u8(&pkt, hash, (hash == NULL) ? 0 : hashlen)
|| !WPACKET_get_total_written(&pkt, &hkdflabellen)
|| !WPACKET_finish(&pkt)) {
WPACKET_cleanup(&pkt);
return 0;
}
ret = EVP_PKEY_derive_init(pctx) <= 0
|| EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
<= 0
|| EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
|| EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
|| EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
|| EVP_PKEY_derive(pctx, out, &outlen) <= 0;
EVP_PKEY_CTX_free(pctx);
return ret == 0;
}
int tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
unsigned int context, X509 *x,
size_t chainidx, int *al)
{
int currv, min_version, max_version, reason;
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_versions)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_start_sub_packet_u8(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
ERR_R_INTERNAL_ERROR);
return 0;
}
reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
if (reason != 0) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS, reason);
return 0;
}
/*
* TODO(TLS1.3): There is some discussion on the TLS list as to wheter
* we should include versions <TLS1.2. For the moment we do. To be
* reviewed later.
*/
for (currv = max_version; currv >= min_version; currv--) {
/* TODO(TLS1.3): Remove this first if clause prior to release!! */
if (currv == TLS1_3_VERSION) {
if (!WPACKET_put_bytes_u16(pkt, TLS1_3_VERSION_DRAFT)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
ERR_R_INTERNAL_ERROR);
return 0;
}
} else if (!WPACKET_put_bytes_u16(pkt, currv)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
ERR_R_INTERNAL_ERROR);
return 0;
}
}
if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
ERR_R_INTERNAL_ERROR);
return 0;
}
return 1;
}
/*
* Add the server's renegotiation binding
*/
int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, int *al)
{
if (!s->s3->send_connection_binding)
return 1;
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_start_sub_packet_u8(pkt)
|| !WPACKET_memcpy(pkt, s->s3->previous_client_finished,
s->s3->previous_client_finished_len)
|| !WPACKET_memcpy(pkt, s->s3->previous_server_finished,
s->s3->previous_server_finished_len)
|| !WPACKET_close(pkt)
|| !WPACKET_close(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_STOC_RENEGOTIATE, ERR_R_INTERNAL_ERROR);
return 0;
}
return 1;
}
int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, int *al)
{
/* Add SRP username if there is one */
if (s->srp_ctx.login == NULL)
return 1;
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_srp)
/* Sub-packet for SRP extension */
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_start_sub_packet_u8(pkt)
/* login must not be zero...internal error if so */
|| !WPACKET_set_flags(pkt, WPACKET_FLAGS_NON_ZERO_LENGTH)
|| !WPACKET_memcpy(pkt, s->srp_ctx.login,
strlen(s->srp_ctx.login))
|| !WPACKET_close(pkt)
|| !WPACKET_close(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SRP, ERR_R_INTERNAL_ERROR);
return 0;
}
return 1;
}
/*
* Add the server's renegotiation binding
*/
EXT_RETURN tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt,
unsigned int context, X509 *x,
size_t chainidx, int *al)
{
if (!s->s3->send_connection_binding)
return EXT_RETURN_NOT_SENT;
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_start_sub_packet_u8(pkt)
|| !WPACKET_memcpy(pkt, s->s3->previous_client_finished,
s->s3->previous_client_finished_len)
|| !WPACKET_memcpy(pkt, s->s3->previous_server_finished,
s->s3->previous_server_finished_len)
|| !WPACKET_close(pkt)
|| !WPACKET_close(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_STOC_RENEGOTIATE, ERR_R_INTERNAL_ERROR);
return EXT_RETURN_FAIL;
}
return EXT_RETURN_SENT;
}
/*
* Construct a psk_kex_modes extension. We only have two modes we know about
* at this stage, so we send both.
*/
int tls_construct_ctos_psk_kex_modes(SSL *s, WPACKET *pkt, unsigned int context,
X509 *x, size_t chainidx, int *al)
{
#ifndef OPENSSL_NO_TLS1_3
/*
* TODO(TLS1.3): Do we want this list to be configurable? For now we always
* just send both supported modes
*/
if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk_kex_modes)
|| !WPACKET_start_sub_packet_u16(pkt)
|| !WPACKET_start_sub_packet_u8(pkt)
|| !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE_DHE)
|| !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE)
|| !WPACKET_close(pkt)
|| !WPACKET_close(pkt)) {
SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK_KEX_MODES, ERR_R_INTERNAL_ERROR);
return 0;
}
s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_KE | TLSEXT_KEX_MODE_FLAG_KE_DHE;
#endif
return 1;
}
/*
* Given a |secret|; a |label| of length |labellen|; and |data| of length
* |datalen| (e.g. typically a hash of the handshake messages), derive a new
* secret |outlen| bytes long and store it in the location pointed to be |out|.
* The |data| value may be zero length. Any errors will be treated as fatal if
* |fatal| is set. Returns 1 on success 0 on failure.
*/
int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
const unsigned char *label, size_t labellen,
const unsigned char *data, size_t datalen,
unsigned char *out, size_t outlen, int fatal)
{
static const unsigned char label_prefix[] = "tls13 ";
EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
int ret;
size_t hkdflabellen;
size_t hashlen;
/*
* 2 bytes for length of derived secret + 1 byte for length of combined
* prefix and label + bytes for the label itself + 1 byte length of hash
* + bytes for the hash itself
*/
unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) +
+ sizeof(label_prefix) + TLS13_MAX_LABEL_LEN
+ 1 + EVP_MAX_MD_SIZE];
WPACKET pkt;
if (pctx == NULL)
return 0;
if (labellen > TLS13_MAX_LABEL_LEN) {
if (fatal) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
ERR_R_INTERNAL_ERROR);
} else {
/*
* Probably we have been called from SSL_export_keying_material(),
* or SSL_export_keying_material_early().
*/
SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
}
EVP_PKEY_CTX_free(pctx);
return 0;
}
hashlen = EVP_MD_size(md);
if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0)
|| !WPACKET_put_bytes_u16(&pkt, outlen)
|| !WPACKET_start_sub_packet_u8(&pkt)
|| !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
|| !WPACKET_memcpy(&pkt, label, labellen)
|| !WPACKET_close(&pkt)
|| !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
|| !WPACKET_get_total_written(&pkt, &hkdflabellen)
|| !WPACKET_finish(&pkt)) {
EVP_PKEY_CTX_free(pctx);
WPACKET_cleanup(&pkt);
if (fatal)
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
ERR_R_INTERNAL_ERROR);
else
SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
return 0;
}
ret = EVP_PKEY_derive_init(pctx) <= 0
|| EVP_PKEY_CTX_hkdf_mode(pctx, EVP_PKEY_HKDEF_MODE_EXPAND_ONLY)
<= 0
|| EVP_PKEY_CTX_set_hkdf_md(pctx, md) <= 0
|| EVP_PKEY_CTX_set1_hkdf_key(pctx, secret, hashlen) <= 0
|| EVP_PKEY_CTX_add1_hkdf_info(pctx, hkdflabel, hkdflabellen) <= 0
|| EVP_PKEY_derive(pctx, out, &outlen) <= 0;
EVP_PKEY_CTX_free(pctx);
if (ret != 0) {
if (fatal)
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
ERR_R_INTERNAL_ERROR);
else
SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR);
}
return ret == 0;
}