/*
* sasl_decode_digest_md5_message()
*
* This is used internally to decode an already encoded DIGEST-MD5 challenge
* message into the seperate attributes.
*
* Parameters:
*
* chlg64 [in] - Pointer to the base64 encoded challenge message.
* nonce [in/out] - The buffer where the nonce will be stored.
* nlen [in] - The length of the nonce buffer.
* realm [in/out] - The buffer where the realm will be stored.
* rlen [in] - The length of the realm buffer.
* alg [in/out] - The buffer where the algorithm will be stored.
* alen [in] - The length of the algorithm buffer.
* qop [in/out] - The buffer where the qop-options will be stored.
* qlen [in] - The length of the qop buffer.
*
* Returns CURLE_OK on success.
*/
static CURLcode sasl_decode_digest_md5_message(const char *chlg64,
char *nonce, size_t nlen,
char *realm, size_t rlen,
char *alg, size_t alen,
char *qop, size_t qlen)
{
CURLcode result = CURLE_OK;
unsigned char *chlg = NULL;
size_t chlglen = 0;
size_t chlg64len = strlen(chlg64);
/* Decode the base-64 encoded challenge message */
if(chlg64len && *chlg64 != '=') {
result = Curl_base64_decode(chlg64, &chlg, &chlglen);
if(result)
return result;
}
/* Ensure we have a valid challenge message */
if(!chlg)
return CURLE_BAD_CONTENT_ENCODING;
/* Retrieve nonce string from the challenge */
if(!sasl_digest_get_key_value((char *)chlg, "nonce=\"", nonce, nlen, '\"')) {
Curl_safefree(chlg);
return CURLE_BAD_CONTENT_ENCODING;
}
/* Retrieve realm string from the challenge */
if(!sasl_digest_get_key_value((char *)chlg, "realm=\"", realm, rlen, '\"')) {
/* Challenge does not have a realm, set empty string [RFC2831] page 6 */
strcpy(realm, "");
}
/* Retrieve algorithm string from the challenge */
if(!sasl_digest_get_key_value((char *)chlg, "algorithm=", alg, alen, ',')) {
Curl_safefree(chlg);
return CURLE_BAD_CONTENT_ENCODING;
}
/* Retrieve qop-options string from the challenge */
if(!sasl_digest_get_key_value((char *)chlg, "qop=\"", qop, qlen, '\"')) {
Curl_safefree(chlg);
return CURLE_BAD_CONTENT_ENCODING;
}
Curl_safefree(chlg);
return CURLE_OK;
}
/*
* Curl_sasl_create_digest_md5_message()
*
* This is used to generate an already encoded DIGEST-MD5 response message
* ready for sending to the recipient.
*
* Parameters:
*
* data [in] - The session handle.
* chlg64 [in] - Pointer to the base64 encoded challenge buffer.
* userp [in] - The user name.
* passdwp [in] - The user's password.
* service [in] - The service type such as www, smtp or pop
* outptr [in/out] - The address where a pointer to newly allocated memory
* holding the result will be stored upon completion.
* outlen [out] - The length of the output message.
*
* Returns CURLE_OK on success.
*/
CURLcode Curl_sasl_create_digest_md5_message(struct SessionHandle *data,
const char* chlg64,
const char* userp,
const char* passwdp,
const char* service,
char **outptr, size_t *outlen)
{
static const char table16[] = "0123456789abcdef";
CURLcode result = CURLE_OK;
unsigned char *chlg = (unsigned char *) NULL;
size_t chlglen = 0;
size_t i;
MD5_context *ctxt;
unsigned char digest[MD5_DIGEST_LEN];
char HA1_hex[2 * MD5_DIGEST_LEN + 1];
char HA2_hex[2 * MD5_DIGEST_LEN + 1];
char resp_hash_hex[2 * MD5_DIGEST_LEN + 1];
char nonce[64];
char realm[128];
char alg[64];
char nonceCount[] = "00000001";
char cnonce[] = "12345678"; /* will be changed */
char method[] = "AUTHENTICATE";
char qop[] = "auth";
char uri[128];
char response[512];
result = Curl_base64_decode(chlg64, &chlg, &chlglen);
if(result)
return result;
/* Retrieve nonce string from the challenge */
if(!sasl_digest_get_key_value(chlg, "nonce=\"", nonce,
sizeof(nonce), '\"')) {
Curl_safefree(chlg);
return CURLE_LOGIN_DENIED;
}
/* Retrieve realm string from the challenge */
if(!sasl_digest_get_key_value(chlg, "realm=\"", realm,
sizeof(realm), '\"')) {
/* Challenge does not have a realm, set empty string [RFC2831] page 6 */
strcpy(realm, "");
}
/* Retrieve algorithm string from the challenge */
if(!sasl_digest_get_key_value(chlg, "algorithm=", alg, sizeof(alg), ',')) {
Curl_safefree(chlg);
return CURLE_LOGIN_DENIED;
}
Curl_safefree(chlg);
/* We do not support other algorithms */
if(strcmp(alg, "md5-sess") != 0)
return CURLE_LOGIN_DENIED;
/* Generate 64 bits of random data */
for(i = 0; i < 8; i++)
cnonce[i] = table16[Curl_rand()%16];
/* So far so good, now calculate A1 and H(A1) according to RFC 2831 */
ctxt = Curl_MD5_init(Curl_DIGEST_MD5);
if(!ctxt)
return CURLE_OUT_OF_MEMORY;
Curl_MD5_update(ctxt, (const unsigned char *) userp,
curlx_uztoui(strlen(userp)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) realm,
curlx_uztoui(strlen(realm)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) passwdp,
curlx_uztoui(strlen(passwdp)));
Curl_MD5_final(ctxt, digest);
ctxt = Curl_MD5_init(Curl_DIGEST_MD5);
if(!ctxt)
return CURLE_OUT_OF_MEMORY;
Curl_MD5_update(ctxt, (const unsigned char *) digest, MD5_DIGEST_LEN);
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) nonce,
curlx_uztoui(strlen(nonce)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) cnonce,
curlx_uztoui(strlen(cnonce)));
Curl_MD5_final(ctxt, digest);
/* Convert calculated 16 octet hex into 32 bytes string */
for(i = 0; i < MD5_DIGEST_LEN; i++)
snprintf(&HA1_hex[2 * i], 3, "%02x", digest[i]);
/* Prepare the URL string */
snprintf(uri, sizeof(uri), "%s/%s", service, realm);
/* Calculate H(A2) */
ctxt = Curl_MD5_init(Curl_DIGEST_MD5);
if(!ctxt)
return CURLE_OUT_OF_MEMORY;
Curl_MD5_update(ctxt, (const unsigned char *) method,
curlx_uztoui(strlen(method)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) uri,
curlx_uztoui(strlen(uri)));
Curl_MD5_final(ctxt, digest);
for(i = 0; i < MD5_DIGEST_LEN; i++)
snprintf(&HA2_hex[2 * i], 3, "%02x", digest[i]);
/* Now calculate the response hash */
ctxt = Curl_MD5_init(Curl_DIGEST_MD5);
if(!ctxt)
return CURLE_OUT_OF_MEMORY;
Curl_MD5_update(ctxt, (const unsigned char *) HA1_hex, 2 * MD5_DIGEST_LEN);
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) nonce,
curlx_uztoui(strlen(nonce)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) nonceCount,
curlx_uztoui(strlen(nonceCount)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) cnonce,
curlx_uztoui(strlen(cnonce)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) qop,
curlx_uztoui(strlen(qop)));
Curl_MD5_update(ctxt, (const unsigned char *) ":", 1);
Curl_MD5_update(ctxt, (const unsigned char *) HA2_hex, 2 * MD5_DIGEST_LEN);
Curl_MD5_final(ctxt, digest);
for(i = 0; i < MD5_DIGEST_LEN; i++)
snprintf(&resp_hash_hex[2 * i], 3, "%02x", digest[i]);
snprintf(response, sizeof(response),
"username=\"%s\",realm=\"%s\",nonce=\"%s\","
"cnonce=\"%s\",nc=\"%s\",digest-uri=\"%s\",response=%s",
userp, realm, nonce,
cnonce, nonceCount, uri, resp_hash_hex);
/* Base64 encode the reply */
return Curl_base64_encode(data, response, 0, outptr, outlen);
}