ssl/s3_enc.c: remove artefact.
[openssl.git] / ssl / s3_enc.c
index cec8fcd3762fedbaf3fb29ceda16f7b32f7b5849..5d8f8ae52a1509e4f1cb1582f9da539694f6a7be 100644 (file)
@@ -139,15 +139,16 @@ static int ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
        EVP_MD_CTX s1;
        unsigned char buf[16],smd[SHA_DIGEST_LENGTH];
        unsigned char c='A';
-       int i,j,k;
+       unsigned int i,j,k;
 
 #ifdef CHARSET_EBCDIC
        c = os_toascii[c]; /*'A' in ASCII */
 #endif
        k=0;
        EVP_MD_CTX_init(&m5);
+       EVP_MD_CTX_set_flags(&m5, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
        EVP_MD_CTX_init(&s1);
-       for (i=0; i<num; i+=MD5_DIGEST_LENGTH)
+       for (i=0; (int)i<num; i+=MD5_DIGEST_LENGTH)
                {
                k++;
                if (k > sizeof buf)
@@ -172,7 +173,7 @@ static int ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
                EVP_DigestUpdate(&m5,s->session->master_key,
                        s->session->master_key_length);
                EVP_DigestUpdate(&m5,smd,SHA_DIGEST_LENGTH);
-               if ((i+MD5_DIGEST_LENGTH) > num)
+               if ((int)(i+MD5_DIGEST_LENGTH) > num)
                        {
                        EVP_DigestFinal_ex(&m5,smd,NULL);
                        memcpy(km,smd,(num-i));
@@ -182,7 +183,7 @@ static int ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
 
                km+=MD5_DIGEST_LENGTH;
                }
-       memset(smd,0,SHA_DIGEST_LENGTH);
+       OPENSSL_cleanse(smd,SHA_DIGEST_LENGTH);
        EVP_MD_CTX_cleanup(&m5);
        EVP_MD_CTX_cleanup(&s1);
        return 1;
@@ -190,26 +191,29 @@ static int ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
 
 int ssl3_change_cipher_state(SSL *s, int which)
        {
-       unsigned char *p,*key_block,*mac_secret;
+       unsigned char *p,*mac_secret;
        unsigned char exp_key[EVP_MAX_KEY_LENGTH];
        unsigned char exp_iv[EVP_MAX_IV_LENGTH];
        unsigned char *ms,*key,*iv,*er1,*er2;
        EVP_CIPHER_CTX *dd;
        const EVP_CIPHER *c;
+#ifndef OPENSSL_NO_COMP
        COMP_METHOD *comp;
+#endif
        const EVP_MD *m;
        EVP_MD_CTX md;
-       int exp,n,i,j,k,cl;
+       int is_exp,n,i,j,k,cl;
        int reuse_dd = 0;
 
-       exp=SSL_C_IS_EXPORT(s->s3->tmp.new_cipher);
+       is_exp=SSL_C_IS_EXPORT(s->s3->tmp.new_cipher);
        c=s->s3->tmp.new_sym_enc;
        m=s->s3->tmp.new_hash;
+#ifndef OPENSSL_NO_COMP
        if (s->s3->tmp.new_compression == NULL)
                comp=NULL;
        else
                comp=s->s3->tmp.new_compression->method;
-       key_block=s->s3->tmp.key_block;
+#endif
 
        if (which & SSL3_CC_READ)
                {
@@ -217,8 +221,12 @@ int ssl3_change_cipher_state(SSL *s, int which)
                        reuse_dd = 1;
                else if ((s->enc_read_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
                        goto err;
+               else
+                       /* make sure it's intialized in case we exit later with an error */
+                       EVP_CIPHER_CTX_init(s->enc_read_ctx);
                dd= s->enc_read_ctx;
                s->read_hash=m;
+#ifndef OPENSSL_NO_COMP
                /* COMPRESS */
                if (s->expand != NULL)
                        {
@@ -239,6 +247,7 @@ int ssl3_change_cipher_state(SSL *s, int which)
                        if (s->s3->rrec.comp == NULL)
                                goto err;
                        }
+#endif
                memset(&(s->s3->read_sequence[0]),0,8);
                mac_secret= &(s->s3->read_mac_secret[0]);
                }
@@ -248,8 +257,12 @@ int ssl3_change_cipher_state(SSL *s, int which)
                        reuse_dd = 1;
                else if ((s->enc_write_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
                        goto err;
+               else
+                       /* make sure it's intialized in case we exit later with an error */
+                       EVP_CIPHER_CTX_init(s->enc_write_ctx);
                dd= s->enc_write_ctx;
                s->write_hash=m;
+#ifndef OPENSSL_NO_COMP
                /* COMPRESS */
                if (s->compress != NULL)
                        {
@@ -265,20 +278,20 @@ int ssl3_change_cipher_state(SSL *s, int which)
                                goto err2;
                                }
                        }
+#endif
                memset(&(s->s3->write_sequence[0]),0,8);
                mac_secret= &(s->s3->write_mac_secret[0]);
                }
 
        if (reuse_dd)
                EVP_CIPHER_CTX_cleanup(dd);
-       EVP_CIPHER_CTX_init(dd);
 
        p=s->s3->tmp.key_block;
        i=EVP_MD_size(m);
        cl=EVP_CIPHER_key_length(c);
-       j=exp ? (cl < SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher) ?
+       j=is_exp ? (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); */
+       /* Was j=(is_exp)?5:EVP_CIPHER_key_length(c); */
        k=EVP_CIPHER_iv_length(c);
        if (    (which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
                (which == SSL3_CHANGE_CIPHER_SERVER_READ))
@@ -307,7 +320,7 @@ int ssl3_change_cipher_state(SSL *s, int which)
 
        EVP_MD_CTX_init(&md);
        memcpy(mac_secret,ms,i);
-       if (exp)
+       if (is_exp)
                {
                /* In here I set both the read and write key/iv to the
                 * same value since only the correct one will be used :-).
@@ -333,8 +346,8 @@ int ssl3_change_cipher_state(SSL *s, int which)
 
        EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
 
-       memset(&(exp_key[0]),0,sizeof(exp_key));
-       memset(&(exp_iv[0]),0,sizeof(exp_iv));
+       OPENSSL_cleanse(&(exp_key[0]),sizeof(exp_key));
+       OPENSSL_cleanse(&(exp_iv[0]),sizeof(exp_iv));
        EVP_MD_CTX_cleanup(&md);
        return(1);
 err:
@@ -363,7 +376,11 @@ int ssl3_setup_key_block(SSL *s)
 
        s->s3->tmp.new_sym_enc=c;
        s->s3->tmp.new_hash=hash;
+#ifdef OPENSSL_NO_COMP
+       s->s3->tmp.new_compression=NULL;
+#else
        s->s3->tmp.new_compression=comp;
+#endif
 
        num=EVP_CIPHER_key_length(c)+EVP_MD_size(hash)+EVP_CIPHER_iv_length(c);
        num*=2;
@@ -408,7 +425,7 @@ void ssl3_cleanup_key_block(SSL *s)
        {
        if (s->s3->tmp.key_block != NULL)
                {
-               memset(s->s3->tmp.key_block,0,
+               OPENSSL_cleanse(s->s3->tmp.key_block,
                        s->s3->tmp.key_block_length);
                OPENSSL_free(s->s3->tmp.key_block);
                s->s3->tmp.key_block=NULL;
@@ -416,12 +433,21 @@ void ssl3_cleanup_key_block(SSL *s)
        s->s3->tmp.key_block_length=0;
        }
 
+/* ssl3_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 is invalid or, if sending, an internal error
+ *       occured.
+ */
 int ssl3_enc(SSL *s, int send)
        {
        SSL3_RECORD *rec;
        EVP_CIPHER_CTX *ds;
        unsigned long l;
-       int bs,i;
+       int bs,i,mac_size=0;
        const EVP_CIPHER *enc;
 
        if (send)
@@ -462,6 +488,9 @@ int ssl3_enc(SSL *s, int send)
 
                        /* we need to add 'i-1' padding bytes */
                        l+=i;
+                       /* the last of these zero bytes will be overwritten
+                        * with the padding length. */
+                       memset(&rec->input[rec->length], 0, i);
                        rec->length+=i;
                        rec->input[l-1]=(i-1);
                        }
@@ -469,36 +498,25 @@ int ssl3_enc(SSL *s, int send)
                if (!send)
                        {
                        if (l == 0 || l%bs != 0)
-                               {
-                               SSLerr(SSL_F_SSL3_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
-                               ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
                                return 0;
-                               }
+                       /* otherwise, rec->length >= bs */
                        }
                
                EVP_Cipher(ds,rec->data,rec->input,l);
 
+               if (s->read_hash != NULL)
+                       mac_size = EVP_MD_size(s->read_hash);
+
                if ((bs != 1) && !send)
-                       {
-                       i=rec->data[l-1]+1;
-                       /* SSL 3.0 bounds the number of padding bytes by the block size;
-                        * padding bytes (except that last) are arbitrary */
-                       if (i > bs)
-                               {
-                               /* 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;
-                               }
-                       rec->length-=i;
-                       }
+                       return ssl3_cbc_remove_padding(s, rec, bs, mac_size);
                }
        return(1);
        }
 
 void ssl3_init_finished_mac(SSL *s)
        {
+       EVP_MD_CTX_set_flags(&(s->s3->finish_dgst1),
+               EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
        EVP_DigestInit_ex(&(s->s3->finish_dgst1),s->ctx->md5, NULL);
        EVP_DigestInit_ex(&(s->s3->finish_dgst2),s->ctx->sha1, NULL);
        }
@@ -535,6 +553,7 @@ static int ssl3_handshake_mac(SSL *s, EVP_MD_CTX *in_ctx,
        EVP_MD_CTX ctx;
 
        EVP_MD_CTX_init(&ctx);
+       EVP_MD_CTX_set_flags(&ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
        EVP_MD_CTX_copy_ex(&ctx,in_ctx);
 
        n=EVP_MD_CTX_size(&ctx);
@@ -566,8 +585,8 @@ int ssl3_mac(SSL *ssl, unsigned char *md, int send)
        EVP_MD_CTX md_ctx;
        const EVP_MD *hash;
        unsigned char *p,rec_char;
-       unsigned int md_size;
-       int npad,i;
+       size_t md_size, orig_len;
+       int npad;
 
        if (send)
                {
@@ -587,36 +606,86 @@ int ssl3_mac(SSL *ssl, unsigned char *md, int send)
        md_size=EVP_MD_size(hash);
        npad=(48/md_size)*md_size;
 
-       /* Chop the digest off the end :-) */
-       EVP_MD_CTX_init(&md_ctx);
-
-       EVP_DigestInit_ex(  &md_ctx,hash, NULL);
-       EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
-       EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
-       EVP_DigestUpdate(&md_ctx,seq,8);
-       rec_char=rec->type;
-       EVP_DigestUpdate(&md_ctx,&rec_char,1);
-       p=md;
-       s2n(rec->length,p);
-       EVP_DigestUpdate(&md_ctx,md,2);
-       EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
-       EVP_DigestFinal_ex( &md_ctx,md,NULL);
-
-       EVP_DigestInit_ex(  &md_ctx,hash, NULL);
-       EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
-       EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
-       EVP_DigestUpdate(&md_ctx,md,md_size);
-       EVP_DigestFinal_ex( &md_ctx,md,&md_size);
-
-       EVP_MD_CTX_cleanup(&md_ctx);
+       /* kludge: ssl3_cbc_remove_padding passes padding length in rec->type */
+       orig_len = rec->length+md_size+((unsigned int)rec->type>>8);
+       rec->type &= 0xff;
+
+       if (!send &&
+           EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+           ssl3_cbc_record_digest_supported(hash))
+               {
+               /* 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. */
+
+               /* npad is, at most, 48 bytes and that's with MD5:
+                *   16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
+                *
+                * With SHA-1 (the largest hash speced for SSLv3) the hash size
+                * goes up 4, but npad goes down by 8, resulting in a smaller
+                * total size. */
+               unsigned char header[75];
+               unsigned j = 0;
+               memcpy(header+j, mac_sec, md_size);
+               j += md_size;
+               memcpy(header+j, ssl3_pad_1, npad);
+               j += npad;
+               memcpy(header+j, seq, 8);
+               j += 8;
+               header[j++] = rec->type;
+               header[j++] = rec->length >> 8;
+               header[j++] = rec->length & 0xff;
+
+               ssl3_cbc_digest_record(
+                       hash,
+                       md, &md_size,
+                       header, rec->input,
+                       rec->length + md_size, orig_len,
+                       mac_sec, md_size,
+                       1 /* is SSLv3 */);
+               }
+       else
+               {
+               unsigned int md_size_u;
+               /* Chop the digest off the end :-) */
+               EVP_MD_CTX_init(&md_ctx);
+
+               EVP_DigestInit_ex( &md_ctx,hash, NULL);
+               EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
+               EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
+               EVP_DigestUpdate(&md_ctx,seq,8);
+               rec_char=rec->type;
+               EVP_DigestUpdate(&md_ctx,&rec_char,1);
+               p=md;
+               s2n(rec->length,p);
+               EVP_DigestUpdate(&md_ctx,md,2);
+               EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
+               EVP_DigestFinal_ex( &md_ctx,md,NULL);
+
+               EVP_DigestInit_ex( &md_ctx,hash, NULL);
+               EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
+               EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
+               EVP_DigestUpdate(&md_ctx,md,md_size);
+               EVP_DigestFinal_ex( &md_ctx,md,&md_size_u);
+               md_size = md_size_u;
+
+               EVP_MD_CTX_cleanup(&md_ctx);
+       }
+
+       ssl3_record_sequence_update(seq);
+       return(md_size);
+       }
+
+void ssl3_record_sequence_update(unsigned char *seq)
+       {
+       int i;
 
        for (i=7; i>=0; i--)
                {
                ++seq[i];
                if (seq[i] != 0) break; 
                }
-
-       return(md_size);
        }
 
 int ssl3_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,