sasl: Moved cram-md5 authentication message creation from smtp.c

Moved the cram-md5 message creation from smtp.c into the sasl module
to allow for use by other modules such as pop3.

1 files changed, 80 insertions, 0 deletions

diff --git a/lib/curl_sasl.c b/lib/curl_sasl.c
index 1725af86e..1889a208e 100644
--- a/lib/curl_sasl.c
+++ b/lib/curl_sasl.c
@@ -18,6 +18,7 @@
  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  * KIND, either express or implied.
  *
+ * RFC2195 CRAM-MD5 authentication
  * RFC4616 PLAIN authentication
  *
  ***************************************************************************/
@@ -28,8 +29,14 @@
 #include "urldata.h"
 
 #include "curl_base64.h"
+#include "curl_md5.h"
+#include "curl_hmac.h"
 #include "curl_ntlm_msgs.h"
 #include "curl_sasl.h"
+#include "warnless.h"
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
 
 /* The last #include file should be: */
 #include "memdebug.h"
@@ -115,6 +122,79 @@ CURLcode Curl_sasl_create_login_message(struct SessionHandle *data,
   return Curl_base64_encode(data, valuep, vlen, outptr, outlen);
 }
 
+#ifndef CURL_DISABLE_CRYPTO_AUTH
+/*
+ * Curl_sasl_create_cram_md5_message()
+ *
+ * This is used to generate an already encoded CRAM-MD5 message ready for
+ * sending to the recipient.
+ *
+ * Parameters:
+ *
+ * data    [in]     - The session handle.
+ * chlg64  [in]     - Pointer to the input buffer.
+ * userp   [in]     - The user name in the format User or Domain\User.
+ * passdwp [in]     - The user's password.
+ * 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_cram_md5_message(struct SessionHandle *data,
+                                           const char* chlg64,
+                                           const char* user,
+                                           const char* passwdp,
+                                           char **outptr, size_t *outlen)
+{
+  CURLcode result = CURLE_OK;
+  size_t chlg64len = strlen(chlg64);
+  size_t len = 0;
+  unsigned char *chlg = (unsigned char *) NULL;
+  size_t chlglen = 0;
+  HMAC_context *ctxt;
+  unsigned char digest[MD5_DIGEST_LEN];
+  char reply[MAX_CURL_USER_LENGTH + 2 * MD5_DIGEST_LEN + 1];
+
+  /* Decode the challenge if necessary */
+  if(chlg64len && *chlg64 != '=') {
+    result = Curl_base64_decode(chlg64, &chlg, &chlglen);
+
+    if(result)
+      return result;
+  }
+
+  /* Compute the digest using the password as the key */
+  ctxt = Curl_HMAC_init(Curl_HMAC_MD5,
+                        (const unsigned char *) passwdp,
+                        curlx_uztoui(strlen(passwdp)));
+
+  if(!ctxt) {
+    Curl_safefree(chlg);
+    return CURLE_OUT_OF_MEMORY;
+  }
+
+  /* Update the digest with the given challenge */
+  if(chlglen > 0)
+    Curl_HMAC_update(ctxt, chlg, curlx_uztoui(chlglen));
+
+  Curl_safefree(chlg);
+
+  /* Finalise the digest */
+  Curl_HMAC_final(ctxt, digest);
+
+  /* Prepare the reply */
+  snprintf(reply, sizeof(reply),
+      "%s %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
+           user, digest[0], digest[1], digest[2], digest[3], digest[4],
+           digest[5], digest[6], digest[7], digest[8], digest[9], digest[10],
+           digest[11], digest[12], digest[13], digest[14], digest[15]);
+
+  /* Base64 encode the reply */
+  return Curl_base64_encode(data, reply, 0, outptr, outlen);
+}
+#endif
+
 #ifdef USE_NTLM
 /*
  * Curl_sasl_create_ntlm_type1_message()