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checkpassword patch now with PLAIN, CRYPT, MD5, CRAM-MD5, and APOP



Woohoo, I'm on a roll now. Heh, it's getting to be a real #ifdef orgy. This
latest version adds PLAIN and APOP authentication modes. See the README_SQL
file for details.

Instructions:

tar xzf checkpassword-0.90.tar.gz
cd checkpassword-0.90
patch -p1 < checkpassword-0.90-sql.latest.patch
patch -p1 < this_patch
more README_SQL
$EDITOR sqltype.h sql.headers sql.lib conf-cc
make

-- 
Alex Howansky
Wankwood Associates
http://www.wankwood.com/



diff -Nu checkpassword-0.90-sql/Makefile checkpassword-0.90-new/Makefile
--- checkpassword-0.90-sql/Makefile	Tue Oct 28 19:50:47 2003
+++ checkpassword-0.90-new/Makefile	Tue Oct 28 23:35:29 2003
@@ -160,6 +160,10 @@
 compile hier.c auto_home.h
 	./compile hier.c

+hmac_md5.o: \
+compile hmac_md5.c hmac_md5.h
+	./compile hmac_md5.c
+
 install: \
 load install.o hier.o auto_home.o unix.a byte.a
 	./load install hier.o auto_home.o unix.a byte.a
@@ -207,6 +211,14 @@
 	) > makelib
 	chmod 755 makelib

+md5asc.o: \
+compile md5asc.c md5asc.h
+	./compile md5asc.c
+
+md5c.o: \
+compile md5c.c md5.h
+	./compile md5c.c
+
 open_read.o: \
 compile open_read.c open.h
 	./compile open_read.c
@@ -309,13 +321,15 @@
 buffer_get.o buffer_put.o env.o error.o error_str.o open_read.o \
 open_trunc.o pathexec_env.o pathexec_run.o prot.o stralloc_cat.o \
 stralloc_catb.o stralloc_cats.o stralloc_eady.o stralloc_opyb.o \
-stralloc_opys.o stralloc_pend.o strerr_die.o strerr_sys.o
+stralloc_opys.o stralloc_pend.o strerr_die.o strerr_sys.o md5c.o \
+md5asc.o hmac_md5.o
 	./makelib unix.a alloc.o alloc_re.o buffer.o buffer_2.o \
 	buffer_copy.o buffer_get.o buffer_put.o env.o error.o \
 	error_str.o open_read.o open_trunc.o pathexec_env.o \
 	pathexec_run.o prot.o stralloc_cat.o stralloc_catb.o \
 	stralloc_cats.o stralloc_eady.o stralloc_opyb.o \
-	stralloc_opys.o stralloc_pend.o strerr_die.o strerr_sys.o
+	stralloc_opys.o stralloc_pend.o strerr_die.o strerr_sys.o \
+	md5c.o md5asc.o hmac_md5.o

 # Copied from Qmail 1.03
 haswaitp.h: \
diff -Nu checkpassword-0.90-sql/README_SQL checkpassword-0.90-new/README_SQL
--- checkpassword-0.90-sql/README_SQL	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/README_SQL	Wed Oct 29 03:15:26 2003
@@ -0,0 +1,45 @@
+There are two distinct modes of operation: encrypted and plaintext.
+Encrypted mode requires passwords in the database to be encrypted,
+and plaintext mode requires passwords in the database to be plain
+text. The distinction is important because certain authentication
+mechanisms (like CRAM-MD5 and APOP) require plaintext passwords. The
+options you choose will determine which mode you get. If conflicting
+options are specified, compilation will abort with an error.
+
+Encrypted mode supports two types of authentication: CRYPT and
+MD5_PLAIN. CRYPT mode expects the passwords in your database to be
+hashed with the standard crypt() function. This alone is the default,
+backwards compatible mode. To enable CRYPT authentication, specify
+-DCRYPT in conf-cc.
+
+Encrypted mode also supports MD5_PLAIN authentication. This mode
+expects the passwords in your database to be hashed with the MD5
+algorithm. To enable MD5_PLAIN authentication, specify -DMD5_PLAIN.
+
+If you would like the special combination mode which allows the use
+of both CRYPT and MD5_PLAIN at the same time, specify both -DCRYPT
+and -DMD5_PLAIN. You may mix and match CRYPT and MD5_PLAIN passwords
+in the database, and checkpassword will automatically detect the
+type and utilize the appropriate method.
+
+Plaintext mode supports three types of authentication: PLAIN, APOP,
+and CRAM-MD5. With PLAIN mode, specified by -DPLAIN, authentication
+is performed by a straight string comparison against the stored
+password. If you would like to enable APOP authentication, specify
+-DAPOP. If you would like to enable CRAM-MD5 authentication, specify
+-DCRAM_MD5. Any combination of the three plaintext types is allowed.
+If PLAIN is selected in combination with APOP and/or CRAM-MD5, then
+APOP and/or CRAM-MD5 will be tried first, and failing that, a PLAIN
+check will be made.
+
+Other defines available:
+
+-DSHOW_FAIL
+    Show bad passwords in log when authentication fails.
+
+-DLOG_EMPTY
+    Generate a log entry when an empty password is encountered.
+
+-DDEBUG
+    Show extra authentication information in the log. This includes
+    passwords, so use with care!
diff -Nu checkpassword-0.90-sql/TARGETS checkpassword-0.90-new/TARGETS
--- checkpassword-0.90-sql/TARGETS	Tue Oct 28 19:50:47 2003
+++ checkpassword-0.90-new/TARGETS	Wed Oct 29 03:10:07 2003
@@ -63,3 +63,6 @@
 wait_pid.o
 checksmtpauth.o
 checksmtpauth
+md5c.o
+md5asc.o
+hmac_md5.o
diff -Nu checkpassword-0.90-sql/checkpassword.c checkpassword-0.90-new/checkpassword.c
--- checkpassword-0.90-sql/checkpassword.c	Tue Oct 28 19:50:47 2003
+++ checkpassword-0.90-new/checkpassword.c	Wed Oct 29 03:06:57 2003
@@ -4,7 +4,59 @@
 #include "prot.h"
 #include <sys/stat.h>

+#ifdef CRYPT
+#define ENCRYPTED
+#endif /* CRYPT */
+
+#ifdef MD5_PLAIN
+#define ENCRYPTED
+#define REQUIRES_MD5
+#endif /* MD5_PLAIN */
+
+#ifdef PLAIN
+#define PLAINTEXT
+#endif /* PLAIN */
+
+#ifdef CRAM_MD5
+#define PLAINTEXT
+#define REQUIRES_MD5
+#define REQUIRES_HMAC
+#define REQUIRES_RESPONSE
+#endif /* CRAM_MD5 */
+
+#ifdef APOP
+#define PLAINTEXT
+#define REQUIRES_MD5
+#define REQUIRES_RESPONSE
+#endif /* APOP */
+
+#ifdef ENCRYPTED
+#ifdef PLAINTEXT
+#ERROR__CONFLICTING_DEFINES_SEE_README_SQL
+#endif /* PLAINTEXT */
+#endif /* ENCRYPTED */
+
+#ifndef ENCRYPTED
+#ifndef PLAINTEXT
+#ERROR__MISSING_REQUIRED_DEFINES_SEE_README_SQL
+#endif /* PLAINTEXT */
+#endif /* ENCRYPTED */
+
+#ifdef CRYPT
 extern char *crypt();
+#endif /* CRYPT */
+
+#ifdef REQUIRES_MD5
+#include <string.h>
+#include "global.h"
+#include "md5.h"
+#include "md5asc.h"
+#endif /* REQUIRES_MD5 */
+
+#ifdef REQUIRES_HMAC
+#include "hmac_md5.h"
+#endif /* REQUIRES_HMAC */
+
 #include <pwd.h>
 static struct passwd *pw;

@@ -31,8 +83,15 @@
 main(int argc,char **argv)
 {
   char *login;
-  char *password;
-  char *encrypted;
+  char *chalpass;
+#ifdef REQUIRES_RESPONSE
+  char *response;
+#endif /* REQUIRES_RESPONSE */
+#ifdef REQUIRES_MD5
+  MD5_CTX context;
+  unsigned char md5_bin[16];
+  char md5_asc[33];
+#endif /* REQUIRES_MD5 */
   char *stored;
   int r;
   int i;
@@ -60,9 +119,12 @@
   if (i >= uplen) _exit(2);
   login = up + i;
   while (up[i++]) if (i >= uplen) _exit(2);
-  password = up + i;
+  chalpass = up + i;
   if (i >= uplen) _exit(2);
   while (up[i++]) if (i >= uplen) _exit(2);
+#ifdef REQUIRES_RESPONSE
+  response = up + i;
+#endif /* REQUIRES_RESPONSE */

   really_use_db=sql_get_config(&sqlconfig);
   virtual_host=login;
@@ -124,14 +186,163 @@
     }
   }
   if (!stored) _exit(1);
-
-  encrypted = crypt(password,stored);
-
-  if (!*stored || strcmp(encrypted,stored)) {
-     syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password");
-    _exit(1);
+
+  if (!*stored) {
+#ifdef LOG_EMPTY
+     syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: empty password");
+#endif /* LOG_EMPTY */
+     _exit(1);
   }

+#ifdef DEBUG
+  syslog (LOG_NOTICE | LOG_MAIL, "DEBUG login = %s", login);
+  syslog (LOG_NOTICE | LOG_MAIL, "DEBUG challenge/password = %s", chalpass);
+#ifdef REQUIRES_RESPONSE
+  syslog (LOG_NOTICE | LOG_MAIL, "DEBUG response/timestamp = %s", response);
+#endif /* REQUIRES_RESPONSE */
+#endif /* DEBUG */
+
+#ifdef CRAM_MD5
+  if (*chalpass == '<' && *response != '<' && strlen(response) == 32) {
+    hmac_md5(chalpass, strlen(chalpass), stored, strlen(stored), md5_bin);
+    md5asc(md5_bin, md5_asc);
+    if (strcmp(md5_asc, response)) {
+#ifdef SHOW_FAIL
+      syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (CRAM-MD5) [%s]", response);
+#else /* SHOW_FAIL */
+      syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (CRAM-MD5)");
+#endif /* SHOW_FAIL */
+      _exit(1);
+    }
+  }
+#endif /* CRAM_MD5 */
+
+#ifdef CRAM_MD5
+#ifdef APOP
+  else {
+#endif /* APOP */
+#ifdef PLAIN
+#ifndef APOP
+  else {
+#endif /* APOP */
+#endif /* PLAIN */
+#endif /* CRAM_MD5 */
+
+#ifdef APOP
+    if (*chalpass != '<' && *response == '<' && strlen(chalpass) == 32) {
+      MD5Init(&context);
+      MD5Update(&context, response, strlen(response));
+      MD5Update(&context, stored, strlen(stored));
+      MD5Final(md5_bin, &context);
+      md5asc(md5_bin, md5_asc);
+      if (strcmp(md5_asc, chalpass)) {
+#ifdef SHOW_FAIL
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (APOP) [%s]", chalpass);
+#else /* SHOW_FAIL */
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (APOP)");
+#endif /* SHOW_FAIL */
+        _exit(1);
+      }
+    }
+#endif /* APOP */
+
+#ifdef APOP
+#ifdef PLAIN
+    else {
+#endif /* PLAIN */
+#endif /* APOP */
+
+#ifdef PLAIN
+      if (strcmp(chalpass, stored)) {
+#ifdef SHOW_FAIL
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (PLAIN) [%s]", chalpass);
+#else /* SHOW_FAIL */
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (PLAIN)");
+#endif /* SHOW_FAIL */
+        _exit(1);
+      }
+#endif /* PLAIN */
+
+#ifdef PLAINTEXT
+#ifndef PLAIN
+      else {
+#ifdef SHOW_FAIL
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: unsupported password format [%s]", chalpass);
+#else /* SHOW_FAIL */
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: unsupported password format");
+#endif /* SHOW_FAIL */
+        _exit(1);
+      }
+#endif /* PLAIN */
+#endif /* PLAINTEXT */
+
+#ifdef APOP
+#ifdef PLAIN
+    }
+#endif /* PLAIN */
+#endif /* APOP */
+
+#ifdef CRAM_MD5
+#ifdef APOP
+  }
+#endif /* APOP */
+#ifdef PLAIN
+#ifndef APOP
+  }
+#endif /* APOP */
+#endif /* PLAIN */
+#endif /* CRAM_MD5 */
+
+#ifdef CRYPT
+  if (strlen(stored) == 13) {
+    if (strcmp((char *)crypt(chalpass,stored), stored)) {
+#ifdef SHOW_FAIL
+       syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (CRYPT) [%s]", chalpass);
+#else /* SHOW_FAIL */
+       syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (CRYPT)");
+#endif /* SHOW_FAIL */
+      _exit(1);
+    }
+  }
+#ifdef MD5_PLAIN
+  else {
+#endif /* MD5_PLAIN */
+#endif /* CRYPT */
+
+#ifdef MD5_PLAIN
+    if (strlen(stored) == 32) {
+      MD5Init(&context);
+      MD5Update(&context, chalpass, strlen(chalpass));
+      MD5Final(md5_bin, &context);
+      md5asc(md5_bin, md5_asc);
+      if (strcmp(md5_asc, stored)) {
+#ifdef SHOW_FAIL
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (MD5) [%s]", chalpass);
+#else
+        syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (MD5)");
+#endif
+        _exit(1);
+      }
+    }
+#endif /* MD5_PLAIN */
+
+#ifdef ENCRYPTED
+    else {
+#ifdef SHOW_FAIL
+      syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: unsupported password format [%s]", chalpass);
+#else
+      syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: unsupported password format");
+#endif
+      _exit(1);
+    }
+#endif /* ENCRYPTED */
+
+#ifdef CRYPT
+#ifdef MD5_PLAIN
+  }
+#endif /* MD5_PLAIN */
+#endif /* CRYPT */
+
 #ifndef SMTP_AUTH
   if(stat(pw->pw_dir,&st) != 0 && sqlconfig.autohomedir &&
      stat(sqlconfig.autohomedir,&st) == 0) {
@@ -160,9 +371,7 @@
     updatelastlogin(login,virtual_host, &sqlconfig);
   sql_close(&sqlconfig);

-#ifndef SMTP_AUTH
   for (i = 0;i < sizeof(up);++i) up[i] = 0;
-#endif

   syslog (LOG_MAIL | LOG_NOTICE , "Authentication succeeded");
 #ifndef SMTP_AUTH
diff -Nu checkpassword-0.90-sql/conf-cc checkpassword-0.90-new/conf-cc
--- checkpassword-0.90-sql/conf-cc	Sat Dec 23 01:40:46 2000
+++ checkpassword-0.90-new/conf-cc	Wed Oct 29 03:10:27 2003
@@ -1,3 +1,3 @@
-gcc -O2
+gcc -O2 -DLOG_EMPTY -DCRYPT

 This will be used to compile .c files.
diff -Nu checkpassword-0.90-sql/global.h checkpassword-0.90-new/global.h
--- checkpassword-0.90-sql/global.h	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/global.h	Mon Oct 27 23:53:32 2003
@@ -0,0 +1,48 @@
+/* GLOBAL.H - RSAREF types and constants */
+
+#include <string.h>
+
+/* Copyright (C) RSA Laboratories, a division of RSA Data Security,
+     Inc., created 1991. All rights reserved.
+ */
+
+#ifndef _GLOBAL_H_
+#define _GLOBAL_H_ 1
+
+/* PROTOTYPES should be set to one if and only if the compiler supports
+     function argument prototyping.
+   The following makes PROTOTYPES default to 1 if it has not already been
+     defined as 0 with C compiler flags.
+ */
+#ifndef PROTOTYPES
+#define PROTOTYPES 1
+#endif
+
+/* POINTER defines a generic pointer type */
+typedef unsigned char *POINTER;
+
+/* UINT2 defines a two byte word */
+typedef unsigned short int UINT2;
+
+/* UINT4 defines a four byte word */
+typedef unsigned long int UINT4;
+
+#ifndef NULL_PTR
+#define NULL_PTR ((POINTER)0)
+#endif
+
+#ifndef UNUSED_ARG
+#define UNUSED_ARG(x) x = *(&x);
+#endif
+
+/* PROTO_LIST is defined depending on how PROTOTYPES is defined above.
+   If using PROTOTYPES, then PROTO_LIST returns the list, otherwise it
+     returns an empty list.
+ */
+#if PROTOTYPES
+#define PROTO_LIST(list) list
+#else
+#define PROTO_LIST(list) ()
+#endif
+
+#endif /* end _GLOBAL_H_ */
diff -Nu checkpassword-0.90-sql/hmac_md5.c checkpassword-0.90-new/hmac_md5.c
--- checkpassword-0.90-sql/hmac_md5.c	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/hmac_md5.c	Mon Oct 27 23:53:32 2003
@@ -0,0 +1,42 @@
+#include "global.h"
+#include "md5.h"
+
+/* See RFC2104 */
+
+void hmac_md5 (unsigned char *text, int text_len, unsigned char *key, int key_len, unsigned char *digest)
+{
+    MD5_CTX context;
+    unsigned char k_ipad[65];
+    unsigned char k_opad[65];
+    unsigned char tk[16];
+    int i;
+
+    if (key_len > 64) {
+        MD5_CTX tctx;
+        MD5Init(&tctx);
+        MD5Update(&tctx, key, key_len);
+        MD5Final(tk, &tctx);
+        key = tk;
+        key_len = 16;
+    }
+
+    bzero(k_ipad, sizeof k_ipad);
+    bzero(k_opad, sizeof k_opad);
+    bcopy(key, k_ipad, key_len);
+    bcopy(key, k_opad, key_len);
+
+    for (i = 0; i < 64; i++) {
+        k_ipad[i] ^= 0x36;
+        k_opad[i] ^= 0x5c;
+    }
+
+    MD5Init(&context);
+    MD5Update(&context, k_ipad, 64);
+    MD5Update(&context, text, text_len);
+    MD5Final(digest, &context);
+
+    MD5Init(&context);
+    MD5Update(&context, k_opad, 64);
+    MD5Update(&context, digest, 16);
+    MD5Final(digest, &context);
+}
diff -Nu checkpassword-0.90-sql/hmac_md5.h checkpassword-0.90-new/hmac_md5.h
--- checkpassword-0.90-sql/hmac_md5.h	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/hmac_md5.h	Tue Oct 28 20:53:30 2003
@@ -0,0 +1 @@
+void hmac_md5(unsigned char* text, int text_len, unsigned char* key, int key_len, unsigned char* digest);
diff -Nu checkpassword-0.90-sql/md5.h checkpassword-0.90-new/md5.h
--- checkpassword-0.90-sql/md5.h	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/md5.h	Mon Oct 27 23:53:32 2003
@@ -0,0 +1,49 @@
+/* MD5.H - header file for MD5C.C
+ */
+
+/* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
+   rights reserved.
+
+   License to copy and use this software is granted provided that it
+   is identified as the "RSA Data Security, Inc. MD5 Message-Digest
+   Algorithm" in all material mentioning or referencing this software
+   or this function.
+
+   License is also granted to make and use derivative works provided
+   that such works are identified as "derived from the RSA Data
+   Security, Inc. MD5 Message-Digest Algorithm" in all material
+   mentioning or referencing the derived work.
+
+   RSA Data Security, Inc. makes no representations concerning either
+   the merchantability of this software or the suitability of this
+   software for any particular purpose. It is provided "as is"
+   without express or implied warranty of any kind.
+
+   These notices must be retained in any copies of any part of this
+   documentation and/or software.
+ */
+
+#ifndef _MD5_H_
+#define _MD5_H_ 1
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* MD5 context. */
+typedef struct {
+  UINT4 state[4];                                   /* state (ABCD) */
+  UINT4 count[2];        /* number of bits, modulo 2^64 (lsb first) */
+  unsigned char buffer[64];                         /* input buffer */
+} MD5_CTX;
+
+void MD5Init PROTO_LIST ((MD5_CTX *));
+void MD5Update PROTO_LIST
+  ((MD5_CTX *, unsigned char *, unsigned int));
+void MD5Final PROTO_LIST ((unsigned char [16], MD5_CTX *));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff -Nu checkpassword-0.90-sql/md5asc.c checkpassword-0.90-new/md5asc.c
--- checkpassword-0.90-sql/md5asc.c	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/md5asc.c	Tue Oct 28 23:53:33 2003
@@ -0,0 +1,11 @@
+#include "md5asc.h"
+
+void md5asc (unsigned char *bin, char *asc)
+{
+    int i;
+    for (i = 0; i < 16; i++) {
+        asc[i << 1] = hexmap[bin[i] >> 4];
+        asc[(i << 1) + 1] = hexmap[bin[i] & 0x0f];
+    }
+    asc[32] = '\0';
+}
diff -Nu checkpassword-0.90-sql/md5asc.h checkpassword-0.90-new/md5asc.h
--- checkpassword-0.90-sql/md5asc.h	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/md5asc.h	Tue Oct 28 23:23:19 2003
@@ -0,0 +1,8 @@
+#ifndef MD5ASC_H
+#define MD5ASC_H
+
+static char hexmap[] = "0123456789abcdef";
+
+void md5asc (unsigned char *bin, char *asc);
+
+#endif /* MD5ASC_H */
diff -Nu checkpassword-0.90-sql/md5c.c checkpassword-0.90-new/md5c.c
--- checkpassword-0.90-sql/md5c.c	Wed Dec 31 19:00:00 1969
+++ checkpassword-0.90-new/md5c.c	Mon Oct 27 23:53:32 2003
@@ -0,0 +1,334 @@
+/* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
+ */
+
+/* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
+   rights reserved.
+
+   License to copy and use this software is granted provided that it
+   is identified as the "RSA Data Security, Inc. MD5 Message-Digest
+   Algorithm" in all material mentioning or referencing this software
+   or this function.
+
+   License is also granted to make and use derivative works provided
+   that such works are identified as "derived from the RSA Data
+   Security, Inc. MD5 Message-Digest Algorithm" in all material
+   mentioning or referencing the derived work.
+
+   RSA Data Security, Inc. makes no representations concerning either
+   the merchantability of this software or the suitability of this
+   software for any particular purpose. It is provided "as is"
+   without express or implied warranty of any kind.
+
+   These notices must be retained in any copies of any part of this
+   documentation and/or software.
+ */
+
+#include "global.h"
+#include "md5.h"
+
+/* Constants for MD5Transform routine.
+ */
+#define S11 7
+#define S12 12
+#define S13 17
+#define S14 22
+#define S21 5
+#define S22 9
+#define S23 14
+#define S24 20
+#define S31 4
+#define S32 11
+#define S33 16
+#define S34 23
+#define S41 6
+#define S42 10
+#define S43 15
+#define S44 21
+
+static void MD5Transform PROTO_LIST ((UINT4 [4], unsigned char [64]));
+static void Encode PROTO_LIST
+  ((unsigned char *, UINT4 *, unsigned int));
+static void Decode PROTO_LIST
+  ((UINT4 *, unsigned char *, unsigned int));
+static void MD5_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int));
+static void MD5_memset PROTO_LIST ((POINTER, int, unsigned int));
+
+static unsigned char PADDING[64] = {
+  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+/* F, G, H and I are basic MD5 functions.
+ */
+#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
+#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
+#define H(x, y, z) ((x) ^ (y) ^ (z))
+#define I(x, y, z) ((y) ^ ((x) | (~z)))
+
+/* ROTATE_LEFT rotates x left n bits.
+ */
+#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
+
+/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
+   Rotation is separate from addition to prevent recomputation.
+ */
+#define FF(a, b, c, d, x, s, ac) { \
+    (a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
+    (a) = ROTATE_LEFT ((a), (s)); \
+    (a) += (b); \
+  }
+#define GG(a, b, c, d, x, s, ac) { \
+    (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
+    (a) = ROTATE_LEFT ((a), (s)); \
+    (a) += (b); \
+  }
+#define HH(a, b, c, d, x, s, ac) { \
+    (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
+    (a) = ROTATE_LEFT ((a), (s)); \
+    (a) += (b); \
+  }
+#define II(a, b, c, d, x, s, ac) { \
+    (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
+    (a) = ROTATE_LEFT ((a), (s)); \
+    (a) += (b); \
+  }
+
+/* MD5 initialization. Begins an MD5 operation, writing a new context.
+ */
+void MD5Init (context)
+MD5_CTX *context;                                        /* context */
+{
+  context->count[0] = context->count[1] = 0;
+
+  /* Load magic initialization constants.
+   */
+  context->state[0] = 0x67452301;
+  context->state[1] = 0xefcdab89;
+  context->state[2] = 0x98badcfe;
+  context->state[3] = 0x10325476;
+}
+
+/* MD5 block update operation. Continues an MD5 message-digest
+     operation, processing another message block, and updating the
+     context.
+ */
+void MD5Update (context, input, inputLen)
+MD5_CTX *context;                                        /* context */
+unsigned char *input;                                /* input block */
+unsigned int inputLen;                     /* length of input block */
+{
+  unsigned int i, index, partLen;
+
+  /* Compute number of bytes mod 64 */
+  index = (unsigned int)((context->count[0] >> 3) & 0x3F);
+
+  /* Update number of bits */
+  if ((context->count[0] += ((UINT4)inputLen << 3))
+      < ((UINT4)inputLen << 3))
+    context->count[1]++;
+  context->count[1] += ((UINT4)inputLen >> 29);
+
+  partLen = 64 - index;
+
+  /* Transform as many times as possible.
+   */
+  if (inputLen >= partLen) {
+    MD5_memcpy
+      ((POINTER)&context->buffer[index], (POINTER)input, partLen);
+    MD5Transform (context->state, context->buffer);
+
+    for (i = partLen; i + 63 < inputLen; i += 64)
+      MD5Transform (context->state, &input[i]);
+
+    index = 0;
+  }
+  else
+    i = 0;
+
+  /* Buffer remaining input */
+  MD5_memcpy
+    ((POINTER)&context->buffer[index], (POINTER)&input[i],
+     inputLen-i);
+}
+
+/* MD5 finalization. Ends an MD5 message-digest operation, writing the
+     the message digest and zeroizing the context.
+ */
+void MD5Final (digest, context)
+unsigned char digest[16];                         /* message digest */
+MD5_CTX *context;                                       /* context */
+{
+  unsigned char bits[8];
+  unsigned int index, padLen;
+
+  /* Save number of bits */
+  Encode (bits, context->count, 8);
+
+  /* Pad out to 56 mod 64.
+   */
+  index = (unsigned int)((context->count[0] >> 3) & 0x3f);
+  padLen = (index < 56) ? (56 - index) : (120 - index);
+  MD5Update (context, PADDING, padLen);
+
+  /* Append length (before padding) */
+  MD5Update (context, bits, 8);
+
+  /* Store state in digest */
+  Encode (digest, context->state, 16);
+
+  /* Zeroize sensitive information.
+   */
+  MD5_memset ((POINTER)context, 0, sizeof (*context));
+}
+
+/* MD5 basic transformation. Transforms state based on block.
+ */
+static void MD5Transform (state, block)
+UINT4 state[4];
+unsigned char block[64];
+{
+  UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
+
+  Decode (x, block, 64);
+
+  /* Round 1 */
+  FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
+  FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
+  FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
+  FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
+  FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
+  FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
+  FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
+  FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
+  FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
+  FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
+  FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
+  FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
+  FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
+  FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
+  FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
+  FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
+
+  /* Round 2 */
+  GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
+  GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
+  GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
+  GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
+  GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
+  GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
+  GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
+  GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
+  GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
+  GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
+  GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
+  GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
+  GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
+  GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
+  GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
+  GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
+
+  /* Round 3 */
+  HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
+  HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
+  HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
+  HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
+  HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
+  HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
+  HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
+  HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
+  HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
+  HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
+  HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
+  HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
+  HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
+  HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
+  HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
+  HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
+
+  /* Round 4 */
+  II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
+  II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
+  II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
+  II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
+  II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
+  II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
+  II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
+  II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
+  II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
+  II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
+  II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
+  II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
+  II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
+  II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
+  II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
+  II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
+
+  state[0] += a;
+  state[1] += b;
+  state[2] += c;
+  state[3] += d;
+
+  /* Zeroize sensitive information.
+   */
+  MD5_memset ((POINTER)x, 0, sizeof (x));
+}
+
+/* Encodes input (UINT4) into output (unsigned char). Assumes len is
+     a multiple of 4.
+ */
+static void Encode (output, input, len)
+unsigned char *output;
+UINT4 *input;
+unsigned int len;
+{
+  unsigned int i, j;
+
+  for (i = 0, j = 0; j < len; i++, j += 4) {
+    output[j] = (unsigned char)(input[i] & 0xff);
+    output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
+    output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
+    output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
+  }
+}
+
+/* Decodes input (unsigned char) into output (UINT4). Assumes len is
+     a multiple of 4.
+ */
+static void Decode (output, input, len)
+UINT4 *output;
+unsigned char *input;
+unsigned int len;
+{
+  unsigned int i, j;
+
+  for (i = 0, j = 0; j < len; i++, j += 4)
+    output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
+      (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
+}
+
+/* Note: Replace "for loop" with standard memcpy if possible.
+ */
+static void MD5_memcpy (output, input, len)
+POINTER output;
+POINTER input;
+unsigned int len;
+{
+  unsigned int i;
+
+  for (i = 0; i < len; i++)
+    output[i] = input[i];
+}
+
+/* Note: Replace "for loop" with standard memset if possible.
+ */
+static void MD5_memset (output, value, len)
+POINTER output;
+int value;
+unsigned int len;
+{
+  unsigned int i;
+
+  for (i = 0; i < len; i++)
+    ((char *)output)[i] = (char)value;
+}