diff options
Diffstat (limited to 'ssl')
| -rw-r--r-- | ssl/ssl_lib.c | 12 | ||||
| -rw-r--r-- | ssl/ssl_locl.h | 6 | ||||
| -rw-r--r-- | ssl/statem/statem.c | 15 | ||||
| -rw-r--r-- | ssl/statem/statem.h | 1 | ||||
| -rw-r--r-- | ssl/tls13_enc.c | 70 |
5 files changed, 104 insertions, 0 deletions
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c index 00e02f4..59b507e 100644 --- a/ssl/ssl_lib.c +++ b/ssl/ssl_lib.c @@ -2810,6 +2810,18 @@ int SSL_export_keying_material(SSL *s, unsigned char *out, size_t olen, contextlen, use_context); } +int SSL_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) +{ + if (s->version != TLS1_3_VERSION) + return 0; + + return tls13_export_keying_material_early(s, out, olen, label, llen, + context, contextlen); +} + static unsigned long ssl_session_hash(const SSL_SESSION *a) { const unsigned char *session_id = a->session_id; diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h index b590b53..0dd2a7b 100644 --- a/ssl/ssl_locl.h +++ b/ssl/ssl_locl.h @@ -1111,6 +1111,7 @@ struct ssl_st { unsigned char client_app_traffic_secret[EVP_MAX_MD_SIZE]; unsigned char server_app_traffic_secret[EVP_MAX_MD_SIZE]; unsigned char exporter_master_secret[EVP_MAX_MD_SIZE]; + unsigned char early_exporter_master_secret[EVP_MAX_MD_SIZE]; EVP_CIPHER_CTX *enc_read_ctx; /* cryptographic state */ unsigned char read_iv[EVP_MAX_IV_LENGTH]; /* TLSv1.3 static read IV */ EVP_MD_CTX *read_hash; /* used for mac generation */ @@ -2406,6 +2407,11 @@ __owur int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen, const char *label, size_t llen, const unsigned char *context, size_t contextlen, int use_context); +__owur 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); __owur int tls1_alert_code(int code); __owur int tls13_alert_code(int code); __owur int ssl3_alert_code(int code); diff --git a/ssl/statem/statem.c b/ssl/statem/statem.c index 818e648..a574853 100644 --- a/ssl/statem/statem.c +++ b/ssl/statem/statem.c @@ -951,3 +951,18 @@ int ossl_statem_export_allowed(SSL *s) return s->s3->previous_server_finished_len != 0 && s->statem.hand_state != TLS_ST_SW_FINISHED; } + +/* + * Return 1 if early TLS exporter is ready to export keying material, + * or 0 if otherwise. + */ +int ossl_statem_export_early_allowed(SSL *s) +{ + /* + * The early exporter secret is only present on the server if we + * have accepted early_data. It is present on the client as long + * as we have sent early_data. + */ + return s->ext.early_data == SSL_EARLY_DATA_ACCEPTED + || (!s->server && s->ext.early_data != SSL_EARLY_DATA_NOT_SENT); +} diff --git a/ssl/statem/statem.h b/ssl/statem/statem.h index 58cc4f4..1935718 100644 --- a/ssl/statem/statem.h +++ b/ssl/statem/statem.h @@ -133,6 +133,7 @@ void ossl_statem_check_finish_init(SSL *s, int send); void ossl_statem_set_hello_verify_done(SSL *s); __owur int ossl_statem_app_data_allowed(SSL *s); __owur int ossl_statem_export_allowed(SSL *s); +__owur int ossl_statem_export_early_allowed(SSL *s); /* Flush the write BIO */ int statem_flush(SSL *s); diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c index 9311866..6332804 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; +} |