Regarding openssl function ssl3_handshake_mac

[Suchindra Chandrahas]

Hi All,
               Just went through this in openssl source in s3_enc.c:

static int ssl3_handshake_mac(SSL *s, EVP_MD_CTX *in_ctx,
             const char *sender, int len, unsigned char *p)
        {
        unsigned int ret;
        int npad,n;
        unsigned int i;
        unsigned char md_buf[EVP_MAX_MD_SIZE];
        EVP_MD_CTX ctx;

        EVP_MD_CTX_init(&ctx);
        EVP_MD_CTX_copy_ex(&ctx,in_ctx);

        n=EVP_MD_CTX_size(&ctx);
        npad=(48/n)*n;

        if (sender != NULL)
                EVP_DigestUpdate(&ctx,sender,len);
        EVP_DigestUpdate(&ctx,s->session->master_key,
                s->session->master_key_length);
        EVP_DigestUpdate(&ctx,ssl3_pad_1,npad);
        EVP_DigestFinal_ex(&ctx,md_buf,&i);

        EVP_DigestInit_ex(&ctx,EVP_MD_CTX_md(&ctx), NULL);
        EVP_DigestUpdate(&ctx,s->session->master_key,
                s->session->master_key_length);
        EVP_DigestUpdate(&ctx,ssl3_pad_2,npad);
        EVP_DigestUpdate(&ctx,md_buf,i);
        EVP_DigestFinal_ex(&ctx,p,&ret);

        EVP_MD_CTX_cleanup(&ctx);


This seems to be the function for generating the final md5 and sha hashes for 
client_finished messages. However, i am not able to find the handshake messages 
in the above EVP_DigestUpdates. But in RFC, the handshake messages are needed 
it says. Am i missing something here, or is this fine for an MD5 or SHA hash to 
be sent in client_finished message? Please let me know if i am wrong!!!

Thanks and Regards,
Suchindra Chandrahas

       
---------------------------------
Never miss a thing.   Make Yahoo your homepage.