Adds multiple checks to avoid buffer over reads
[openssl.git] / ssl / tls13_enc.c
index 44d8ba9eb1bc2c4b2252f693d2a0baad2d644c4e..a793e0c8af431dbb95baef7093889ce9e6e9d23c 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -9,6 +9,7 @@
 
 #include <stdlib.h>
 #include "ssl_locl.h"
+#include "internal/cryptlib.h"
 #include <openssl/evp.h>
 #include <openssl/kdf.h>
 
@@ -58,6 +59,8 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
             || !WPACKET_finish(&pkt)) {
         EVP_PKEY_CTX_free(pctx);
         WPACKET_cleanup(&pkt);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
+                 ERR_R_INTERNAL_ERROR);
         return 0;
     }
 
@@ -71,6 +74,10 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
 
     EVP_PKEY_CTX_free(pctx);
 
+    if (ret != 0)
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND,
+                 ERR_R_INTERNAL_ERROR);
+
     return ret == 0;
 }
 
@@ -127,8 +134,11 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
     static const char derived_secret_label[] = "derived";
     unsigned char preextractsec[EVP_MAX_MD_SIZE];
 
-    if (pctx == NULL)
+    if (pctx == NULL) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
+                 ERR_R_INTERNAL_ERROR);
         return 0;
+    }
 
     mdlen = EVP_MD_size(md);
 
@@ -147,6 +157,8 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
         if (mctx == NULL
                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
+                     ERR_R_INTERNAL_ERROR);
             EVP_MD_CTX_free(mctx);
             EVP_PKEY_CTX_free(pctx);
             return 0;
@@ -158,6 +170,7 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
                                (unsigned char *)derived_secret_label,
                                sizeof(derived_secret_label) - 1, hash, mdlen,
                                preextractsec, mdlen)) {
+            /* SSLfatal() already called */
             EVP_PKEY_CTX_free(pctx);
             return 0;
         }
@@ -176,6 +189,10 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
             || EVP_PKEY_derive(pctx, outsecret, &mdlen)
                <= 0;
 
+    if (ret != 0)
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_GENERATE_SECRET,
+                 ERR_R_INTERNAL_ERROR);
+
     EVP_PKEY_CTX_free(pctx);
     if (prevsecret == preextractsec)
         OPENSSL_cleanse(preextractsec, mdlen);
@@ -190,6 +207,7 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
 int tls13_generate_handshake_secret(SSL *s, const unsigned char *insecret,
                                 size_t insecretlen)
 {
+    /* Calls SSLfatal() if required */
     return tls13_generate_secret(s, ssl_handshake_md(s), s->early_secret,
                                  insecret, insecretlen,
                                  (unsigned char *)&s->handshake_secret);
@@ -207,6 +225,7 @@ int tls13_generate_master_secret(SSL *s, unsigned char *out,
     const EVP_MD *md = ssl_handshake_md(s);
 
     *secret_size = EVP_MD_size(md);
+    /* Calls SSLfatal() if required */
     return tls13_generate_secret(s, md, prev, NULL, 0, out);
 }
 
@@ -223,22 +242,27 @@ size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen,
     EVP_PKEY *key = NULL;
     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
 
-    if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen))
+    if (!ssl_handshake_hash(s, hash, sizeof(hash), &hashlen)) {
+        /* SSLfatal() already called */
         goto err;
+    }
 
     if (str == s->method->ssl3_enc->server_finished_label)
-        key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
-                                   s->server_finished_secret, hashlen);
+        key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
+                                           s->server_finished_secret, hashlen);
     else
-        key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL,
-                                   s->client_finished_secret, hashlen);
+        key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
+                                           s->client_finished_secret, hashlen);
 
     if (key == NULL
             || ctx == NULL
             || EVP_DigestSignInit(ctx, NULL, md, NULL, key) <= 0
             || EVP_DigestSignUpdate(ctx, hash, hashlen) <= 0
-            || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0)
+            || EVP_DigestSignFinal(ctx, out, &hashlen) <= 0) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_FINAL_FINISH_MAC,
+                 ERR_R_INTERNAL_ERROR);
         goto err;
+    }
 
     ret = hashlen;
  err:
@@ -260,7 +284,8 @@ int tls13_setup_key_block(SSL *s)
     s->session->cipher = s->s3->tmp.new_cipher;
     if (!ssl_cipher_get_evp
         (s->session, &c, &hash, &mac_type, NULL, NULL, 0)) {
-        SSLerr(SSL_F_TLS13_SETUP_KEY_BLOCK, SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_SETUP_KEY_BLOCK,
+                 SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
         return 0;
     }
 
@@ -284,7 +309,7 @@ static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 
     if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
                            secret, hashlen)) {
-        SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR);
+        /* SSLfatal() already called */
         goto err;
     }
 
@@ -311,7 +336,7 @@ static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
 
     if (!tls13_derive_key(s, md, secret, key, keylen)
             || !tls13_derive_iv(s, md, secret, iv, ivlen)) {
-        SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR);
+        /* SSLfatal() already called */
         goto err;
     }
 
@@ -320,7 +345,8 @@ static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
                                                 taglen, NULL))
         || EVP_CipherInit_ex(ciph_ctx, NULL, NULL, key, NULL, -1) <= 0) {
-        SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_EVP_LIB);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DERIVE_SECRET_KEY_AND_IV,
+                 ERR_R_EVP_LIB);
         goto err;
     }
 
@@ -339,6 +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];
@@ -360,7 +387,8 @@ int tls13_change_cipher_state(SSL *s, int which)
         } else {
             s->enc_read_ctx = EVP_CIPHER_CTX_new();
             if (s->enc_read_ctx == NULL) {
-                SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
                 goto err;
             }
         }
@@ -369,12 +397,14 @@ int tls13_change_cipher_state(SSL *s, int which)
 
         RECORD_LAYER_reset_read_sequence(&s->rlayer);
     } else {
+        s->statem.invalid_enc_write_ctx = 1;
         if (s->enc_write_ctx != NULL) {
             EVP_CIPHER_CTX_reset(s->enc_write_ctx);
         } else {
             s->enc_write_ctx = EVP_CIPHER_CTX_new();
             if (s->enc_write_ctx == NULL) {
-                SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
                 goto err;
             }
         }
@@ -400,12 +430,33 @@ int tls13_change_cipher_state(SSL *s, int which)
 
             handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
             if (handlen <= 0) {
-                SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE,
-                       SSL_R_BAD_HANDSHAKE_LENGTH);
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS13_CHANGE_CIPHER_STATE,
+                         SSL_R_BAD_HANDSHAKE_LENGTH);
                 goto err;
             }
+
+            if (s->early_data_state == SSL_EARLY_DATA_CONNECTING
+                    && s->max_early_data > 0
+                    && s->session->ext.max_early_data == 0) {
+                /*
+                 * If we are attempting to send early data, and we've decided to
+                 * actually do it but max_early_data in s->session is 0 then we
+                 * must be using an external PSK.
+                 */
+                if (!ossl_assert(s->psksession != NULL
+                        && s->max_early_data ==
+                           s->psksession->ext.max_early_data)) {
+                    SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                             SSL_F_TLS13_CHANGE_CIPHER_STATE,
+                             ERR_R_INTERNAL_ERROR);
+                    goto err;
+                }
+                sslcipher = SSL_SESSION_get0_cipher(s->psksession);
+            }
             if (sslcipher == NULL) {
-                SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS13_CHANGE_CIPHER_STATE, SSL_R_BAD_PSK);
                 goto err;
             }
 
@@ -416,7 +467,8 @@ int tls13_change_cipher_state(SSL *s, int which)
              */
             mdctx = EVP_MD_CTX_new();
             if (mdctx == NULL) {
-                SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
                 goto err;
             }
             cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
@@ -424,12 +476,23 @@ int tls13_change_cipher_state(SSL *s, int which)
             if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
                     || !EVP_DigestUpdate(mdctx, hdata, handlen)
                     || !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
-                SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
                 EVP_MD_CTX_free(mdctx);
                 goto err;
             }
             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;
@@ -482,7 +545,7 @@ int tls13_change_cipher_state(SSL *s, int which)
         cipher = s->s3->tmp.new_sym_enc;
         if (!ssl3_digest_cached_records(s, 1)
                 || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
-            SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+            /* SSLfatal() already called */;
             goto err;
         }
     }
@@ -507,45 +570,46 @@ int tls13_change_cipher_state(SSL *s, int which)
                                sizeof(resumption_master_secret) - 1,
                                hashval, hashlen, s->session->master_key,
                                hashlen)) {
-            SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+            /* SSLfatal() already called */
             goto err;
         }
         s->session->master_key_length = hashlen;
-
-        /* Now we create the exporter master secret */
-        if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
-                               exporter_master_secret,
-                               sizeof(exporter_master_secret) - 1,
-                               hash, hashlen, s->exporter_master_secret,
-                               hashlen)) {
-            SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
-            goto err;
-        }
     }
 
     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
                                   insecret, hash, label, labellen, secret, iv,
                                   ciph_ctx)) {
+        /* SSLfatal() already called */
         goto err;
     }
 
-    if (label == server_application_traffic)
+    if (label == server_application_traffic) {
         memcpy(s->server_app_traffic_secret, secret, hashlen);
-    else if (label == client_application_traffic)
+        /* Now we create the exporter master secret */
+        if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
+                               exporter_master_secret,
+                               sizeof(exporter_master_secret) - 1,
+                               hash, hashlen, s->exporter_master_secret,
+                               hashlen)) {
+            /* SSLfatal() already called */
+            goto err;
+        }
+    } else if (label == client_application_traffic)
         memcpy(s->client_app_traffic_secret, secret, hashlen);
 
     if (!ssl_log_secret(s, log_label, secret, hashlen)) {
-        SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+        /* SSLfatal() already called */
         goto err;
     }
 
     if (finsecret != NULL
             && !tls13_derive_finishedkey(s, ssl_handshake_md(s), secret,
                                          finsecret, finsecretlen)) {
-        SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+        /* SSLfatal() already called */
         goto err;
     }
 
+    s->statem.invalid_enc_write_ctx = 0;
     ret = 1;
  err:
     OPENSSL_cleanse(secret, sizeof(secret));
@@ -568,6 +632,7 @@ int tls13_update_key(SSL *s, int sending)
         insecret = s->client_app_traffic_secret;
 
     if (sending) {
+        s->statem.invalid_enc_write_ctx = 1;
         iv = s->write_iv;
         ciph_ctx = s->enc_write_ctx;
         RECORD_LAYER_reset_write_sequence(&s->rlayer);
@@ -581,11 +646,14 @@ int tls13_update_key(SSL *s, int sending)
                                   s->s3->tmp.new_sym_enc, insecret, NULL,
                                   application_traffic,
                                   sizeof(application_traffic) - 1, secret, iv,
-                                  ciph_ctx))
+                                  ciph_ctx)) {
+        /* SSLfatal() already called */
         goto err;
+    }
 
     memcpy(insecret, secret, hashlen);
 
+    s->statem.invalid_enc_write_ctx = 0;
     ret = 1;
  err:
     OPENSSL_cleanse(secret, sizeof(secret));
@@ -607,13 +675,13 @@ int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
 {
     unsigned char exportsecret[EVP_MAX_MD_SIZE];
     static const unsigned char exporterlabel[] = "exporter";
-    unsigned char hash[EVP_MAX_MD_SIZE];
+    unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
     const EVP_MD *md = ssl_handshake_md(s);
     EVP_MD_CTX *ctx = EVP_MD_CTX_new();
-    unsigned int hashsize;
+    unsigned int hashsize, datalen;
     int ret = 0;
 
-    if (ctx == NULL || !SSL_is_init_finished(s))
+    if (ctx == NULL || !ossl_statem_export_allowed(s))
         goto err;
 
     if (!use_context)
@@ -622,9 +690,70 @@ int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
     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->exporter_master_secret,
-                                  (const unsigned char *)label, llen, NULL, 0,
-                                  exportsecret, hashsize)
+                                  (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;
+}
+
+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))