[balsa] Use glib for digest calculations

[Peter Bloomfield <peterb src gnome org>]

commit df413c511c068a167a27225fe98f85c528dcea7e
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Tue Jan 3 19:25:14 2017 -0500

    Use glib for digest calculations
    
        * libbalsa/imap/auth-cram.c (imap_auth_cram):
        * libbalsa/imap/pop3.c (compute_auth_hash):

 ChangeLog                 |    7 ++++
 libbalsa/imap/auth-cram.c |   70 ++------------------------------------------
 libbalsa/imap/pop3.c      |   28 ++++-------------
 3 files changed, 18 insertions(+), 87 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 8b894a6..a09df5f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2017-01-03  Albrecht Dreß
+
+       Use glib for digest calculations
+
+       * libbalsa/imap/auth-cram.c (imap_auth_cram):
+       * libbalsa/imap/pop3.c (compute_auth_hash):
+
 2016-12-28  Pawel Salek <pawsa0 gmail com>
 
        * libbalsa/imap/imap-tls.c: avoid warnings with openssl-1.1.x
diff --git a/libbalsa/imap/auth-cram.c b/libbalsa/imap/auth-cram.c
index c29d327..6d95fbc 100644
--- a/libbalsa/imap/auth-cram.c
+++ b/libbalsa/imap/auth-cram.c
@@ -25,7 +25,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <glib.h>
-#include <openssl/evp.h>
 
 #include "imap-auth.h"
 #include "util.h"
@@ -34,21 +33,15 @@
 
 #define LONG_STRING 1024
 
-#define MD5_DIGEST_LEN 16
-
-/* forward declarations */
-static void hmac_md5(const char* password, char* challenge,
-                     unsigned char* response);
-
 /* imap_auth_cram_md5: AUTH=CRAM-MD5 support. */
 ImapResult
 imap_auth_cram(ImapMboxHandle* handle)
 {
   char ibuf[LONG_STRING*2], obuf[LONG_STRING];
-  unsigned char hmac_response[MD5_DIGEST_LEN];
   unsigned cmdno;
   int len, rc, ok;
   char *user = NULL, *pass = NULL;
+  gchar *digest;
 
   if (!imap_mbox_handle_can_do(handle, IMCAP_ACRAM_MD5))
     return IMAP_AUTH_UNAVAIL;
@@ -101,14 +94,9 @@ imap_auth_cram(ImapMboxHandle* handle)
    *   around them when the bug report comes in. Until then, we'll remain
    *   blissfully RFC-compliant.
    */
-  hmac_md5 (pass, obuf, hmac_response);
-  g_snprintf (obuf, sizeof (obuf),
-    "%s %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
-    user,
-    hmac_response[0], hmac_response[1], hmac_response[2], hmac_response[3],
-    hmac_response[4], hmac_response[5], hmac_response[6], hmac_response[7],
-    hmac_response[8], hmac_response[9], hmac_response[10], hmac_response[11],
-    hmac_response[12], hmac_response[13], hmac_response[14], hmac_response[15]);
+  digest = g_compute_hmac_for_string(G_CHECKSUM_MD5, (const guchar *) pass, strlen(pass), obuf, -1);
+  g_snprintf (obuf, sizeof (obuf), "%s %s", user, digest);
+  g_free(digest);
   /* XXX - ibuf must be long enough to store the base64 encoding of obuf, 
    * plus the additional debris
    */
@@ -124,53 +112,3 @@ imap_auth_cram(ImapMboxHandle* handle)
 
   return rc == IMR_OK ? IMAP_SUCCESS : IMAP_AUTH_FAILURE;
 }
-
-/* hmac_md5: produce CRAM-MD5 challenge response. */
-#define MD5_BLOCK_LEN  64
-static void
-hmac_md5 (const char* password, char* challenge,
-          unsigned char* response)
-{  
-  EVP_MD_CTX *ctx = EVP_MD_CTX_create();
-  unsigned char ipad[MD5_BLOCK_LEN], opad[MD5_BLOCK_LEN];
-  unsigned char secret[MD5_BLOCK_LEN+1];
-  unsigned int secret_len, chal_len;
-  int i;
-
-  secret_len = strlen(password);
-  chal_len = strlen(challenge);
-
-  /* passwords longer than MD5_BLOCK_LEN bytes are substituted with their MD5
-   * digests */
-  if (secret_len > MD5_BLOCK_LEN) {
-       EVP_DigestInit(ctx, EVP_md5());
-       EVP_DigestUpdate(ctx, (const unsigned char*) password, secret_len);
-       EVP_DigestFinal(ctx, secret, &secret_len);
-  }
-  else
-    strncpy ((char *) secret, password, sizeof (secret));
-
-  memset (ipad, 0, sizeof(ipad));
-  memset (opad, 0, sizeof(opad));
-  memcpy (ipad, secret, secret_len);
-  memcpy (opad, secret, secret_len);
-
-  for (i=0; i<MD5_BLOCK_LEN; i++) {
-    ipad[i] ^= 0x36;
-    opad[i] ^= 0x5c;
-  }
-
-  /* inner hash: challenge and ipadded secret */
-  EVP_DigestInit(ctx, EVP_md5());
-  EVP_DigestUpdate(ctx, ipad, MD5_BLOCK_LEN);
-  EVP_DigestUpdate(ctx, (unsigned char*) challenge, chal_len);
-  EVP_DigestFinal(ctx, response, NULL);
-
-  /* outer hash: inner hash and opadded secret */
-  EVP_DigestInit(ctx, EVP_md5());
-  EVP_DigestUpdate(ctx, opad, MD5_BLOCK_LEN);
-  EVP_DigestUpdate(ctx, response, MD5_DIGEST_LEN);
-  EVP_DigestFinal(ctx, response, NULL);
-
-  EVP_MD_CTX_destroy(ctx);
-}
diff --git a/libbalsa/imap/pop3.c b/libbalsa/imap/pop3.c
index a72ce61..de52327 100644
--- a/libbalsa/imap/pop3.c
+++ b/libbalsa/imap/pop3.c
@@ -28,7 +28,6 @@
 #include <unistd.h>
 
 #include <openssl/ssl.h>
-#include <openssl/evp.h>
 #include <openssl/err.h>
 
 #include "pop3.h"
@@ -310,26 +309,13 @@ get_apop_stamp(const char *greeting, char *stamp)
 static void
 compute_auth_hash(char *stamp, char *hash, const char *passwd)
 {
-  EVP_MD_CTX* ctx = EVP_MD_CTX_create();
-  register unsigned char *dp;
-  register char *cp;
-  unsigned char *ep;
-  unsigned char digest[16];
-  
-  EVP_DigestInit(ctx, EVP_md5());
-  EVP_DigestUpdate(ctx, stamp, strlen(stamp));
-  EVP_DigestUpdate(ctx, passwd, strlen(passwd));
-  EVP_DigestFinal(ctx, digest, NULL);
-  EVP_MD_CTX_destroy(ctx);
-  
-  cp = hash;
-  dp = digest;
-  for(ep = dp + sizeof(digest)/sizeof(digest[0]); dp < ep; cp += 2) {
-    sprintf(cp, "%02x", *dp);
-    dp++;
-  }
-    
-  *cp = '\0';
+       GChecksum *ctx;
+
+       ctx = g_checksum_new(G_CHECKSUM_MD5);
+       g_checksum_update(ctx, (const guchar *) stamp, -1);
+       g_checksum_update(ctx, (const guchar *) passwd, -1);
+       strncpy(hash, g_checksum_get_string(ctx), POP_LINE_LEN);
+       g_checksum_free(ctx);
 }
 
 static ImapResult