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patch which allows checkpassword to handle both MD5 and crypted passwords



Hi all,

Here is a patch (to be applied over Michael's patch for checkpassword-0.90)
which gives checkpassword (and checksmtpauth) the ability to authenticate users
when their passwords are hashed with MD5. It still retains the ability to
authenticate crypted passwords as well, and will automatically select the
correct method to use based on whatever type of password the queried user has
in the database. In other words, you can have some users with crypted passwords
and some with MD5 passwords, if you so desired.

(At first I added just the MD5 capability, then I realized that since crypted
passwords are always exactly 13 chars and MD5 passwords are always exactly 32
chars, it's trivial to tell which kind of password the user has. As a result,
it's really easy to support both at the same time. This dual support will also
allow the standard qmail-sql distribution to include this patch without
breaking backwards compatibility.)

I haven't tested it extensively (i.e., in production) but it worked fine as far
as I've used it. Standard disclaimer applies, etc.

-- 
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	Sun Oct 26 21:00:11 2003
+++ checkpassword-0.90-new/Makefile	Sun Oct 26 20:31:56 2003
@@ -207,6 +207,10 @@
 	) > makelib
 	chmod 755 makelib

+md5c.o: \
+compile md5c.c md5.h
+	./compile md5c.c
+
 open_read.o: \
 compile open_read.c open.h
 	./compile open_read.c
@@ -309,12 +313,12 @@
 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
 	./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_cats.o stralloc_eady.o stralloc_opyb.o md5c.o \
 	stralloc_opys.o stralloc_pend.o strerr_die.o strerr_sys.o

 # Copied from Qmail 1.03
diff -Nu checkpassword-0.90-sql/TARGETS checkpassword-0.90-new/TARGETS
--- checkpassword-0.90-sql/TARGETS	Sun Oct 26 21:00:11 2003
+++ checkpassword-0.90-new/TARGETS	Sun Oct 26 21:00:31 2003
@@ -63,3 +63,4 @@
 wait_pid.o
 checksmtpauth.o
 checksmtpauth
+md5c.o
diff -Nu checkpassword-0.90-sql/checkpassword.c checkpassword-0.90-new/checkpassword.c
--- checkpassword-0.90-sql/checkpassword.c	Sun Oct 26 21:00:11 2003
+++ checkpassword-0.90-new/checkpassword.c	Sun Oct 26 20:45:54 2003
@@ -3,6 +3,9 @@
 #include "pathexec.h"
 #include "prot.h"
 #include <sys/stat.h>
+#include "global.h"
+#include "md5.h"
+#include <string.h>

 extern char *crypt();
 #include <pwd.h>
@@ -33,6 +36,9 @@
   char *login;
   char *password;
   char *encrypted;
+  char encrypted_md5[33];
+  unsigned char md5[16];
+  unsigned char *hex = "0123456789abcdef";
   char *stored;
   int r;
   int i;
@@ -41,6 +47,7 @@
   char *(args[4]);
   char *p;
   int found_separator=0;
+  MD5_CTX context;

   if (!argv[1]) _exit(2);

@@ -124,12 +131,26 @@
     }
   }
   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 (strlen(stored) == 13) {
+    encrypted = crypt(password,stored);
+    if (!*stored || strcmp(encrypted,stored)) {
+       syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (crypt)");
+      _exit(1);
+    }
+  } else {
+    MD5Init(&context);
+    MD5Update(&context, password, strlen(password));
+    MD5Final(md5, &context);
+    for (i = 0; i < 16; i++) {
+      encrypted_md5[i<<1] = hex[(md5[i] & 0xf0) >> 4];
+      encrypted_md5[(i<<1)+1] = hex[md5[i] & 0x0f];
+    }
+    encrypted_md5[32] = '\0';
+    if (!*stored || strcmp(encrypted_md5,stored)) {
+       syslog (LOG_NOTICE | LOG_MAIL, "Authentication failed: bad password (MD5)");
+      _exit(1);
+    }
   }

 #ifndef SMTP_AUTH
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	Sun Oct 26 18:15:37 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/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	Sun Oct 26 18:14:27 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/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	Sun Oct 26 18:14:27 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;
+}