Check EVP errors for handshake digests.
[openssl.git] / ssl / t1_enc.c
index 2b3fd30..72015f5 100644 (file)
@@ -171,6 +171,8 @@ static int tls1_P_hash(const EVP_MD *md, const unsigned char *sec,
 
        EVP_MD_CTX_init(&ctx);
        EVP_MD_CTX_init(&ctx_tmp);
+       EVP_MD_CTX_set_flags(&ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
+       EVP_MD_CTX_set_flags(&ctx_tmp, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
        mac_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
        if (!mac_key)
                goto err;
@@ -263,6 +265,8 @@ static int tls1_PRF(long digest_mask,
                if ((m<<TLS1_PRF_DGST_SHIFT) & digest_mask) count++;
        }       
        len=slen/count;
+       if (count == 1)
+               slen = 0;
        S1=sec;
        memset(out1,0,olen);
        for (idx=0;ssl_get_handshake_digest(idx,&m,&md);idx++) {
@@ -291,7 +295,7 @@ static int tls1_generate_key_block(SSL *s, unsigned char *km,
             unsigned char *tmp, int num)
        {
        int ret;
-       ret = tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+       ret = tls1_PRF(ssl_get_algorithm2(s),
                 TLS_MD_KEY_EXPANSION_CONST,TLS_MD_KEY_EXPANSION_CONST_SIZE,
                 s->s3->server_random,SSL3_RANDOM_SIZE,
                 s->s3->client_random,SSL3_RANDOM_SIZE,
@@ -357,7 +361,7 @@ int tls1_change_cipher_state(SSL *s, int which)
        {
         int i;
         for (i=0; i<s->s3->tmp.key_block_length; i++)
-               printf("%02x", key_block[i]);  printf("\n");
+               printf("%02x", s->s3->tmp.key_block[i]);  printf("\n");
         }
 #endif /* KSSL_DEBUG */
 
@@ -365,7 +369,7 @@ int tls1_change_cipher_state(SSL *s, int which)
                {
                if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
                        s->mac_flags |= SSL_MAC_FLAG_READ_MAC_STREAM;
-                       else
+               else
                        s->mac_flags &= ~SSL_MAC_FLAG_READ_MAC_STREAM;
 
                if (s->enc_read_ctx != NULL)
@@ -452,7 +456,11 @@ int tls1_change_cipher_state(SSL *s, int which)
        j=is_export ? (cl < SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher) ?
                       cl : SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher)) : cl;
        /* Was j=(exp)?5:EVP_CIPHER_key_length(c); */
-       k=EVP_CIPHER_iv_length(c);
+       /* If GCM mode only part of IV comes from PRF */
+       if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
+               k = EVP_GCM_TLS_FIXED_IV_LEN;
+       else
+               k=EVP_CIPHER_iv_length(c);
        if (    (which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
                (which == SSL3_CHANGE_CIPHER_SERVER_READ))
                {
@@ -481,10 +489,14 @@ int tls1_change_cipher_state(SSL *s, int which)
                }
 
        memcpy(mac_secret,ms,i);
-       mac_key = EVP_PKEY_new_mac_key(mac_type, NULL,
-                       mac_secret,*mac_secret_size);
-       EVP_DigestSignInit(mac_ctx,NULL,m,NULL,mac_key);
-       EVP_PKEY_free(mac_key);
+
+       if (!(EVP_CIPHER_flags(c)&EVP_CIPH_FLAG_AEAD_CIPHER))
+               {
+               mac_key = EVP_PKEY_new_mac_key(mac_type, NULL,
+                               mac_secret,*mac_secret_size);
+               EVP_DigestSignInit(mac_ctx,NULL,m,NULL,mac_key);
+               EVP_PKEY_free(mac_key);
+               }
 #ifdef TLS_DEBUG
 printf("which = %04X\nmac key=",which);
 { int z; for (z=0; z<i; z++) printf("%02X%c",ms[z],((z+1)%16)?' ':'\n'); }
@@ -494,7 +506,7 @@ printf("which = %04X\nmac key=",which);
                /* In here I set both the read and write key/iv to the
                 * same value since only the correct one will be used :-).
                 */
-               if (!tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+               if (!tls1_PRF(ssl_get_algorithm2(s),
                                exp_label,exp_label_len,
                                s->s3->client_random,SSL3_RANDOM_SIZE,
                                s->s3->server_random,SSL3_RANDOM_SIZE,
@@ -505,7 +517,7 @@ printf("which = %04X\nmac key=",which);
 
                if (k > 0)
                        {
-                       if (!tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+                       if (!tls1_PRF(ssl_get_algorithm2(s),
                                        TLS_MD_IV_BLOCK_CONST,TLS_MD_IV_BLOCK_CONST_SIZE,
                                        s->s3->client_random,SSL3_RANDOM_SIZE,
                                        s->s3->server_random,SSL3_RANDOM_SIZE,
@@ -531,7 +543,19 @@ printf("which = %04X\nmac key=",which);
        }
 #endif /* KSSL_DEBUG */
 
-       EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
+       if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
+               {
+               EVP_CipherInit_ex(dd,c,NULL,key,NULL,(which & SSL3_CC_WRITE));
+               EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_GCM_SET_IV_FIXED, k, iv);
+               }
+       else    
+               EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
+
+       /* Needed for "composite" AEADs, such as RC4-HMAC-MD5 */
+       if ((EVP_CIPHER_flags(c)&EVP_CIPH_FLAG_AEAD_CIPHER) && *mac_secret_size)
+               EVP_CIPHER_CTX_ctrl(dd,EVP_CTRL_AEAD_SET_MAC_KEY,
+                               *mac_secret_size,mac_secret);
+
 #ifdef TLS_DEBUG
 printf("which = %04X\nkey=",which);
 { int z; for (z=0; z<EVP_CIPHER_key_length(c); z++) printf("%02X%c",key[z],((z+1)%16)?' ':'\n'); }
@@ -643,19 +667,28 @@ err:
        return(ret);
        }
 
+/* tls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
+ *
+ * Returns:
+ *   0: (in non-constant time) if the record is publically invalid (i.e. too
+ *       short etc).
+ *   1: if the record's padding is valid / the encryption was successful.
+ *   -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
+ *       an internal error occured.
+ */
 int tls1_enc(SSL *s, int send)
        {
        SSL3_RECORD *rec;
        EVP_CIPHER_CTX *ds;
        unsigned long l;
-       int bs,i,ii,j,k,n=0;
+       int bs,i,j,k,pad=0,ret,mac_size=0;
        const EVP_CIPHER *enc;
 
        if (send)
                {
                if (EVP_MD_CTX_md(s->write_hash))
                        {
-                       n=EVP_MD_CTX_size(s->write_hash);
+                       int n=EVP_MD_CTX_size(s->write_hash);
                        OPENSSL_assert(n >= 0);
                        }
                ds=s->enc_write_ctx;
@@ -675,12 +708,12 @@ int tls1_enc(SSL *s, int send)
                        if (ivlen > 1)
                                {
                                if ( rec->data != rec->input)
-                               /* we can't write into the input stream:
-                                * Can this ever happen?? (steve)
-                                */
-                               fprintf(stderr,
-                                       "%s:%d: rec->data != rec->input\n",
-                                       __FILE__, __LINE__);
+                                       /* we can't write into the input stream:
+                                        * Can this ever happen?? (steve)
+                                        */
+                                       fprintf(stderr,
+                                               "%s:%d: rec->data != rec->input\n",
+                                               __FILE__, __LINE__);
                                else if (RAND_bytes(rec->input, ivlen) <= 0)
                                        return -1;
                                }
@@ -690,7 +723,7 @@ int tls1_enc(SSL *s, int send)
                {
                if (EVP_MD_CTX_md(s->read_hash))
                        {
-                       n=EVP_MD_CTX_size(s->read_hash);
+                       int n=EVP_MD_CTX_size(s->read_hash);
                        OPENSSL_assert(n >= 0);
                        }
                ds=s->enc_read_ctx;
@@ -705,18 +738,54 @@ int tls1_enc(SSL *s, int send)
        printf("tls1_enc(%d)\n", send);
 #endif    /* KSSL_DEBUG */
 
-       if ((s->session == NULL) || (ds == NULL) ||
-               (enc == NULL))
+       if ((s->session == NULL) || (ds == NULL) || (enc == NULL))
                {
                memmove(rec->data,rec->input,rec->length);
                rec->input=rec->data;
+               ret = 1;
                }
        else
                {
                l=rec->length;
                bs=EVP_CIPHER_block_size(ds->cipher);
 
-               if ((bs != 1) && send)
+               if (EVP_CIPHER_flags(ds->cipher)&EVP_CIPH_FLAG_AEAD_CIPHER)
+                       {
+                       unsigned char buf[13],*seq;
+
+                       seq = send?s->s3->write_sequence:s->s3->read_sequence;
+
+                       if (s->version == DTLS1_VERSION || s->version == DTLS1_BAD_VER)
+                               {
+                               unsigned char dtlsseq[9],*p=dtlsseq;
+
+                               s2n(send?s->d1->w_epoch:s->d1->r_epoch,p);
+                               memcpy(p,&seq[2],6);
+                               memcpy(buf,dtlsseq,8);
+                               }
+                       else
+                               {
+                               memcpy(buf,seq,8);
+                               for (i=7; i>=0; i--)    /* increment */
+                                       {
+                                       ++seq[i];
+                                       if (seq[i] != 0) break; 
+                                       }
+                               }
+
+                       buf[8]=rec->type;
+                       buf[9]=(unsigned char)(s->version>>8);
+                       buf[10]=(unsigned char)(s->version);
+                       buf[11]=rec->length>>8;
+                       buf[12]=rec->length&0xff;
+                       pad=EVP_CIPHER_CTX_ctrl(ds,EVP_CTRL_AEAD_TLS1_AAD,13,buf);
+                       if (send)
+                               {
+                               l+=pad;
+                               rec->length+=pad;
+                               }
+                       }
+               else if ((bs != 1) && send)
                        {
                        i=bs-((int)l%bs);
 
@@ -737,13 +806,13 @@ int tls1_enc(SSL *s, int send)
 
 #ifdef KSSL_DEBUG
                {
-                unsigned long ui;
+               unsigned long ui;
                printf("EVP_Cipher(ds=%p,rec->data=%p,rec->input=%p,l=%ld) ==>\n",
-                        ds,rec->data,rec->input,l);
+                       ds,rec->data,rec->input,l);
                printf("\tEVP_CIPHER_CTX: %d buf_len, %d key_len [%d %d], %d iv_len\n",
-                        ds->buf_len, ds->cipher->key_len,
-                        DES_KEY_SZ, DES_SCHEDULE_SZ,
-                        ds->cipher->iv_len);
+                       ds->buf_len, ds->cipher->key_len,
+                       DES_KEY_SZ, DES_SCHEDULE_SZ,
+                       ds->cipher->iv_len);
                printf("\t\tIV: ");
                for (i=0; i<ds->cipher->iv_len; i++) printf("%02X", ds->iv[i]);
                printf("\n");
@@ -756,75 +825,41 @@ int tls1_enc(SSL *s, int send)
                if (!send)
                        {
                        if (l == 0 || l%bs != 0)
-                               {
-                               SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
-                               ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
                                return 0;
-                               }
                        }
                
-               EVP_Cipher(ds,rec->data,rec->input,l);
+               i = EVP_Cipher(ds,rec->data,rec->input,l);
+               if ((EVP_CIPHER_flags(ds->cipher)&EVP_CIPH_FLAG_CUSTOM_CIPHER)
+                                               ?(i<0)
+                                               :(i==0))
+                       return -1;      /* AEAD can fail to verify MAC */
+               if (EVP_CIPHER_mode(enc) == EVP_CIPH_GCM_MODE && !send)
+                       {
+                       rec->data += EVP_GCM_TLS_EXPLICIT_IV_LEN;
+                       rec->input += EVP_GCM_TLS_EXPLICIT_IV_LEN;
+                       rec->length -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
+                       }
 
 #ifdef KSSL_DEBUG
                {
-                unsigned long i;
-                printf("\trec->data=");
+               unsigned long i;
+               printf("\trec->data=");
                for (i=0; i<l; i++)
-                        printf(" %02x", rec->data[i]);  printf("\n");
-                }
+                       printf(" %02x", rec->data[i]);  printf("\n");
+               }
 #endif /* KSSL_DEBUG */
 
+               ret = 1;
+               if (EVP_MD_CTX_md(s->read_hash) != NULL)
+                       mac_size = EVP_MD_CTX_size(s->read_hash);
                if ((bs != 1) && !send)
-                       {
-                       ii=i=rec->data[l-1]; /* padding_length */
-                       i++;
-                       /* NB: if compression is in operation the first packet
-                        * may not be of even length so the padding bug check
-                        * cannot be performed. This bug workaround has been
-                        * around since SSLeay so hopefully it is either fixed
-                        * now or no buggy implementation supports compression 
-                        * [steve]
-                        */
-                       if ( (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
-                               && !s->expand)
-                               {
-                               /* First packet is even in size, so check */
-                               if ((memcmp(s->s3->read_sequence,
-                                       "\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
-                                       s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
-                               if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
-                                       i--;
-                               }
-                       /* TLS 1.0 does not bound the number of padding bytes by the block size.
-                        * All of them must have value 'padding_length'. */
-                       if (i > (int)rec->length)
-                               {
-                               /* Incorrect padding. SSLerr() and ssl3_alert are done
-                                * by caller: we don't want to reveal whether this is
-                                * a decryption error or a MAC verification failure
-                                * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
-                               return -1;
-                               }
-                       for (j=(int)(l-i); j<(int)l; j++)
-                               {
-                               if (rec->data[j] != ii)
-                                       {
-                                       /* Incorrect padding */
-                                       return -1;
-                                       }
-                               }
-                       rec->length -=i;
-                       if (s->version >= TLS1_1_VERSION
-                               && EVP_CIPHER_CTX_mode(ds) == EVP_CIPH_CBC_MODE)
-                               {
-                               rec->data += bs;    /* skip the explicit IV */
-                               rec->input += bs;
-                               rec->length -= bs;
-                               }
-                       }
+                       ret = tls1_cbc_remove_padding(s, rec, bs, mac_size);
+               if (pad && !send)
+                       rec->length -= pad;
                }
-       return(1);
+       return ret;
        }
+
 int tls1_cert_verify_mac(SSL *s, int md_nid, unsigned char *out)
        {
        unsigned int ret;
@@ -877,26 +912,27 @@ int tls1_final_finish_mac(SSL *s,
 
        for (idx=0;ssl_get_handshake_digest(idx,&mask,&md);idx++)
                {
-               if (mask & s->s3->tmp.new_cipher->algorithm2)
+               if (mask & ssl_get_algorithm2(s))
                        {
                        int hashsize = EVP_MD_size(md);
-                       if (hashsize < 0 || hashsize > (int)(sizeof buf - (size_t)(q-buf)))
+                       EVP_MD_CTX *hdgst = s->s3->handshake_dgst[idx];
+                       if (!hdgst || hashsize < 0 || hashsize > (int)(sizeof buf - (size_t)(q-buf)))
                                {
                                /* internal error: 'buf' is too small for this cipersuite! */
                                err = 1;
                                }
                        else
                                {
-                               EVP_MD_CTX_copy_ex(&ctx,s->s3->handshake_dgst[idx]);
-                               EVP_DigestFinal_ex(&ctx,q,&i);
-                               if (i != (unsigned int)hashsize) /* can't really happen */
+                               if (!EVP_MD_CTX_copy_ex(&ctx, hdgst) ||
+                                       !EVP_DigestFinal_ex(&ctx,q,&i) ||
+                                       (i != (unsigned int)hashsize))
                                        err = 1;
-                               q+=i;
+                               q+=hashsize;
                                }
                        }
                }
                
-       if (!tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+       if (!tls1_PRF(ssl_get_algorithm2(s),
                        str,slen, buf,(int)(q-buf), NULL,0, NULL,0, NULL,0,
                        s->session->master_key,s->session->master_key_length,
                        out,buf2,sizeof buf2))
@@ -914,10 +950,10 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
        SSL3_RECORD *rec;
        unsigned char *seq;
        EVP_MD_CTX *hash;
-       size_t md_size;
+       size_t md_size, orig_len;
        int i;
        EVP_MD_CTX hmac, *mac_ctx;
-       unsigned char buf[5]; 
+       unsigned char header[13];
        int stream_mac = (send?(ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM):(ssl->mac_flags&SSL_MAC_FLAG_READ_MAC_STREAM));
        int t;
 
@@ -938,12 +974,6 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
        OPENSSL_assert(t >= 0);
        md_size=t;
 
-       buf[0]=rec->type;
-       buf[1]=(unsigned char)(ssl->version>>8);
-       buf[2]=(unsigned char)(ssl->version);
-       buf[3]=rec->length>>8;
-       buf[4]=rec->length&0xff;
-
        /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */
        if (stream_mac) 
                {
@@ -962,17 +992,55 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
                s2n(send?ssl->d1->w_epoch:ssl->d1->r_epoch, p);
                memcpy (p,&seq[2],6);
 
-               EVP_DigestSignUpdate(mac_ctx,dtlsseq,8);
+               memcpy(header, dtlsseq, 8);
                }
        else
-               EVP_DigestSignUpdate(mac_ctx,seq,8);
+               memcpy(header, seq, 8);
+
+       /* kludge: tls1_cbc_remove_padding passes padding length in rec->type */
+       orig_len = rec->length+md_size+((unsigned int)rec->type>>8);
+       rec->type &= 0xff;
 
-       EVP_DigestSignUpdate(mac_ctx,buf,5);
-       EVP_DigestSignUpdate(mac_ctx,rec->input,rec->length);
-       t=EVP_DigestSignFinal(mac_ctx,md,&md_size);
-       OPENSSL_assert(t > 0);
+       header[8]=rec->type;
+       header[9]=(unsigned char)(ssl->version>>8);
+       header[10]=(unsigned char)(ssl->version);
+       header[11]=(rec->length)>>8;
+       header[12]=(rec->length)&0xff;
+
+       if (!send &&
+           EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+           ssl3_cbc_record_digest_supported(mac_ctx))
+               {
+               /* This is a CBC-encrypted record. We must avoid leaking any
+                * timing-side channel information about how many blocks of
+                * data we are hashing because that gives an attacker a
+                * timing-oracle. */
+               ssl3_cbc_digest_record(
+                       mac_ctx,
+                       md, &md_size,
+                       header, rec->input,
+                       rec->length + md_size, orig_len,
+                       ssl->s3->read_mac_secret,
+                       ssl->s3->read_mac_secret_size,
+                       0 /* not SSLv3 */);
+               }
+       else
+               {
+               EVP_DigestSignUpdate(mac_ctx,header,sizeof(header));
+               EVP_DigestSignUpdate(mac_ctx,rec->input,rec->length);
+               t=EVP_DigestSignFinal(mac_ctx,md,&md_size);
+               OPENSSL_assert(t > 0);
+#ifdef OPENSSL_FIPS
+               if (!send && FIPS_mode())
+                       tls_fips_digest_extra(
+                                       ssl->enc_read_ctx,
+                                       mac_ctx, rec->input,
+                                       rec->length, orig_len);
+#endif
+               }
                
-       if (!stream_mac) EVP_MD_CTX_cleanup(&hmac);
+       if (!stream_mac)
+               EVP_MD_CTX_cleanup(&hmac);
 #ifdef TLS_DEBUG
 printf("sec=");
 {unsigned int z; for (z=0; z<md_size; z++) printf("%02X ",mac_sec[z]); printf("\n"); }
@@ -1006,6 +1074,7 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
        const void *co = NULL, *so = NULL;
        int col = 0, sol = 0;
 
+
 #ifdef KSSL_DEBUG
        printf ("tls1_generate_master_secret(%p,%p, %p, %d)\n", s,out, p,len);
 #endif /* KSSL_DEBUG */
@@ -1022,7 +1091,7 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
                }
 #endif
 
-       tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+       tls1_PRF(ssl_get_algorithm2(s),
                TLS_MD_MASTER_SECRET_CONST,TLS_MD_MASTER_SECRET_CONST_SIZE,
                s->s3->client_random,SSL3_RANDOM_SIZE,
                co, col,
@@ -1030,6 +1099,16 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
                so, sol,
                p,len,
                s->session->master_key,buff,sizeof buff);
+#ifdef SSL_DEBUG
+       fprintf(stderr, "Premaster Secret:\n");
+       BIO_dump_fp(stderr, (char *)p, len);
+       fprintf(stderr, "Client Random:\n");
+       BIO_dump_fp(stderr, (char *)s->s3->client_random, SSL3_RANDOM_SIZE);
+       fprintf(stderr, "Server Random:\n");
+       BIO_dump_fp(stderr, (char *)s->s3->server_random, SSL3_RANDOM_SIZE);
+       fprintf(stderr, "Master Secret:\n");
+       BIO_dump_fp(stderr, (char *)s->session->master_key, SSL3_MASTER_SECRET_SIZE);
+#endif
 
 #ifdef KSSL_DEBUG
        printf ("tls1_generate_master_secret() complete\n");
@@ -1037,6 +1116,95 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
        return(SSL3_MASTER_SECRET_SIZE);
        }
 
+int tls1_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)
+       {
+       unsigned char *buff;
+       unsigned char *val = NULL;
+       size_t vallen, currentvalpos;
+       int rv;
+
+#ifdef KSSL_DEBUG
+       printf ("tls1_export_keying_material(%p,%p,%d,%s,%d,%p,%d)\n", s, out, olen, label, llen, p, plen);
+#endif /* KSSL_DEBUG */
+
+       buff = OPENSSL_malloc(olen);
+       if (buff == NULL) goto err2;
+
+       /* construct PRF arguments
+        * we construct the PRF argument ourself rather than passing separate
+        * values into the TLS PRF to ensure that the concatenation of values
+        * does not create a prohibited label.
+        */
+       vallen = llen + SSL3_RANDOM_SIZE * 2;
+       if (use_context)
+               {
+               vallen += 2 + contextlen;
+               }
+
+       val = OPENSSL_malloc(vallen);
+       if (val == NULL) goto err2;
+       currentvalpos = 0;
+       memcpy(val + currentvalpos, (unsigned char *) label, llen);
+       currentvalpos += llen;
+       memcpy(val + currentvalpos, s->s3->client_random, SSL3_RANDOM_SIZE);
+       currentvalpos += SSL3_RANDOM_SIZE;
+       memcpy(val + currentvalpos, s->s3->server_random, SSL3_RANDOM_SIZE);
+       currentvalpos += SSL3_RANDOM_SIZE;
+
+       if (use_context)
+               {
+               val[currentvalpos] = (contextlen >> 8) & 0xff;
+               currentvalpos++;
+               val[currentvalpos] = contextlen & 0xff;
+               currentvalpos++;
+               if ((contextlen > 0) || (context != NULL))
+                       {
+                       memcpy(val + currentvalpos, context, contextlen);
+                       }
+               }
+
+       /* disallow prohibited labels
+        * note that SSL3_RANDOM_SIZE > max(prohibited label len) =
+        * 15, so size of val > max(prohibited label len) = 15 and the
+        * comparisons won't have buffer overflow
+        */
+       if (memcmp(val, TLS_MD_CLIENT_FINISH_CONST,
+                TLS_MD_CLIENT_FINISH_CONST_SIZE) == 0) goto err1;
+       if (memcmp(val, TLS_MD_SERVER_FINISH_CONST,
+                TLS_MD_SERVER_FINISH_CONST_SIZE) == 0) goto err1;
+       if (memcmp(val, TLS_MD_MASTER_SECRET_CONST,
+                TLS_MD_MASTER_SECRET_CONST_SIZE) == 0) goto err1;
+       if (memcmp(val, TLS_MD_KEY_EXPANSION_CONST,
+                TLS_MD_KEY_EXPANSION_CONST_SIZE) == 0) goto err1;
+
+       rv = tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+                     val, vallen,
+                     NULL, 0,
+                     NULL, 0,
+                     NULL, 0,
+                     NULL, 0,
+                     s->session->master_key,s->session->master_key_length,
+                     out,buff,olen);
+
+#ifdef KSSL_DEBUG
+       printf ("tls1_export_keying_material() complete\n");
+#endif /* KSSL_DEBUG */
+       goto ret;
+err1:
+       SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
+       rv = 0;
+       goto ret;
+err2:
+       SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, ERR_R_MALLOC_FAILURE);
+       rv = 0;
+ret:
+       if (buff != NULL) OPENSSL_free(buff);
+       if (val != NULL) OPENSSL_free(val);
+       return(rv);
+       }
+
 int tls1_alert_code(int code)
        {
        switch (code)
@@ -1078,27 +1246,3 @@ int tls1_alert_code(int code)
        default:                        return(-1);
                }
        }
-
-int SSL_tls1_key_exporter(SSL *s, unsigned char *label, int label_len,
-                           unsigned char *context, int context_len,
-                           unsigned char *out, int olen)
-       {
-       unsigned char *tmp;
-       int rv;
-
-       tmp = OPENSSL_malloc(olen);
-
-       if (!tmp)
-               return 0;
-       
-       rv = tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
-                        label, label_len,
-                        s->s3->client_random,SSL3_RANDOM_SIZE,
-                        s->s3->server_random,SSL3_RANDOM_SIZE,
-                        context, context_len, NULL, 0,
-                        s->session->master_key, s->session->master_key_length,
-                        out, tmp, olen);
-
-       OPENSSL_free(tmp);
-       return rv;
-       }