diff options
author | Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com> | 2018-02-04 12:20:37 +0900 |
---|---|---|
committer | Matt Caswell <matt@openssl.org> | 2018-02-26 13:35:54 +0000 |
commit | b38ede8043439d99a3c6c174f17b91875cce66ac (patch) | |
tree | e4766b5fe52ffc7dbd61513a0c220027f479cee3 /ssl/tls13_enc.c | |
parent | e454f3add638fda5c2aa32cd368c8929c0b1eb09 (diff) |
Export keying material using early exporter master secret
This commit adds SSL_export_keying_material_early() which exports
keying material using early exporter master secret.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5252)
Diffstat (limited to 'ssl/tls13_enc.c')
-rw-r--r-- | ssl/tls13_enc.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c index 93118661d6..63328045cc 100644 --- a/ssl/tls13_enc.c +++ b/ssl/tls13_enc.c @@ -365,6 +365,7 @@ int tls13_change_cipher_state(SSL *s, int which) static const unsigned char server_application_traffic[] = "s ap traffic"; static const unsigned char exporter_master_secret[] = "exp master"; static const unsigned char resumption_master_secret[] = "res master"; + static const unsigned char early_exporter_master_secret[] = "e exp master"; unsigned char *iv; unsigned char secret[EVP_MAX_MD_SIZE]; unsigned char hashval[EVP_MAX_MD_SIZE]; @@ -481,6 +482,16 @@ int tls13_change_cipher_state(SSL *s, int which) } hashlen = hashlenui; EVP_MD_CTX_free(mdctx); + + if (!tls13_hkdf_expand(s, md, insecret, + early_exporter_master_secret, + sizeof(early_exporter_master_secret) - 1, + hashval, hashlen, + s->early_exporter_master_secret, hashlen)) { + SSLfatal(s, SSL_AD_INTERNAL_ERROR, + SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); + goto err; + } } else if (which & SSL3_CC_HANDSHAKE) { insecret = s->handshake_secret; finsecret = s->client_finished_secret; @@ -690,3 +701,62 @@ int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen, EVP_MD_CTX_free(ctx); return ret; } + +int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen, + const char *label, size_t llen, + const unsigned char *context, + size_t contextlen) +{ + static const unsigned char exporterlabel[] = "exporter"; + unsigned char exportsecret[EVP_MAX_MD_SIZE]; + unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE]; + const EVP_MD *md; + EVP_MD_CTX *ctx = EVP_MD_CTX_new(); + unsigned int hashsize, datalen; + int ret = 0; + const SSL_CIPHER *sslcipher; + + if (ctx == NULL || !ossl_statem_export_early_allowed(s)) + goto err; + + if (!s->server && s->max_early_data > 0 + && s->session->ext.max_early_data == 0) + sslcipher = SSL_SESSION_get0_cipher(s->psksession); + else + sslcipher = SSL_SESSION_get0_cipher(s->session); + + md = ssl_md(sslcipher->algorithm2); + + /* + * Calculate the hash value and store it in |data|. The reason why + * the empty string is used is that the definition of TLS-Exporter + * is like so: + * + * TLS-Exporter(label, context_value, key_length) = + * HKDF-Expand-Label(Derive-Secret(Secret, label, ""), + * "exporter", Hash(context_value), key_length) + * + * Derive-Secret(Secret, Label, Messages) = + * HKDF-Expand-Label(Secret, Label, + * Transcript-Hash(Messages), Hash.length) + * + * Here Transcript-Hash is the cipher suite hash algorithm. + */ + if (EVP_DigestInit_ex(ctx, md, NULL) <= 0 + || EVP_DigestUpdate(ctx, context, contextlen) <= 0 + || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0 + || EVP_DigestInit_ex(ctx, md, NULL) <= 0 + || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 + || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret, + (const unsigned char *)label, llen, + data, datalen, exportsecret, hashsize) + || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, + sizeof(exporterlabel) - 1, hash, hashsize, + out, olen)) + goto err; + + ret = 1; + err: + EVP_MD_CTX_free(ctx); + return ret; +} |