--- /dev/null
+/* ========================================================================
+ * Copyright 1988-2007 University of Washington
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *
+ * ========================================================================
+ */
+
+/*
+ * Program: CRAM-MD5 authenticator
+ *
+ * Author: Mark Crispin
+ * Networks and Distributed Computing
+ * Computing & Communications
+ * University of Washington
+ * Administration Building, AG-44
+ * Seattle, WA 98195
+ * Internet: MRC@CAC.Washington.EDU
+ *
+ * Date: 21 October 1998
+ * Last Edited: 30 January 2007
+ */
+\f
+/* MD5 context */
+
+#define MD5BLKLEN 64 /* MD5 block length */
+#define MD5DIGLEN 16 /* MD5 digest length */
+
+typedef struct {
+ unsigned long chigh; /* high 32bits of byte count */
+ unsigned long clow; /* low 32bits of byte count */
+ unsigned long state[4]; /* state (ABCD) */
+ unsigned char buf[MD5BLKLEN]; /* input buffer */
+ unsigned char *ptr; /* buffer position */
+} MD5CONTEXT;
+
+
+/* Prototypes */
+
+long auth_md5_valid (void);
+long auth_md5_client (authchallenge_t challenger,authrespond_t responder,
+ char *service,NETMBX *mb,void *stream,
+ unsigned long *trial,char *user);
+char *auth_md5_server (authresponse_t responder,int argc,char *argv[]);
+char *auth_md5_pwd (char *user);
+char *apop_login (char *chal,char *user,char *md5,int argc,char *argv[]);
+char *hmac_md5 (char *text,unsigned long tl,char *key,unsigned long kl);
+void md5_init (MD5CONTEXT *ctx);
+void md5_update (MD5CONTEXT *ctx,unsigned char *data,unsigned long len);
+void md5_final (unsigned char *digest,MD5CONTEXT *ctx);
+static void md5_transform (unsigned long *state,unsigned char *block);
+static void md5_encode (unsigned char *dst,unsigned long *src,int len);
+static void md5_decode (unsigned long *dst,unsigned char *src,int len);
+
+
+/* Authenticator linkage */
+
+AUTHENTICATOR auth_md5 = {
+ AU_SECURE, /* secure authenticator */
+ "CRAM-MD5", /* authenticator name */
+ auth_md5_valid, /* check if valid */
+ auth_md5_client, /* client method */
+ auth_md5_server, /* server method */
+ NIL /* next authenticator */
+};
+\f
+/* Check if CRAM-MD5 valid on this system
+ * Returns: T, always
+ */
+
+long auth_md5_valid (void)
+{
+ struct stat sbuf;
+ /* server forbids MD5 if no MD5 enable file */
+ if (stat (MD5ENABLE,&sbuf)) auth_md5.server = NIL;
+ return T; /* MD5 is otherwise valid */
+}
+
+
+/* Client authenticator
+ * Accepts: challenger function
+ * responder function
+ * SASL service name
+ * parsed network mailbox structure
+ * stream argument for functions
+ * pointer to current trial count
+ * returned user name
+ * Returns: T if success, NIL otherwise, number of trials incremented if retry
+ */
+
+long auth_md5_client (authchallenge_t challenger,authrespond_t responder,
+ char *service,NETMBX *mb,void *stream,
+ unsigned long *trial,char *user)
+{
+ char pwd[MAILTMPLEN];
+ void *challenge;
+ unsigned long clen;
+ long ret = NIL;
+ /* get challenge */
+ if (challenge = (*challenger) (stream,&clen)) {
+ pwd[0] = NIL; /* prompt user */
+ mm_login (mb,user,pwd,*trial);
+ if (!pwd[0]) { /* user requested abort */
+ fs_give ((void **) &challenge);
+ (*responder) (stream,NIL,0);
+ *trial = 0; /* cancel subsequent attempts */
+ ret = LONGT; /* will get a BAD response back */
+ }
+ else { /* got password, build response */
+ sprintf (pwd,"%.65s %.33s",user,hmac_md5 (challenge,clen,
+ pwd,strlen (pwd)));
+ fs_give ((void **) &challenge);
+ /* send credentials, allow retry if OK */
+ if ((*responder) (stream,pwd,strlen (pwd))) {
+ if (challenge = (*challenger) (stream,&clen))
+ fs_give ((void **) &challenge);
+ else {
+ ++*trial; /* can try again if necessary */
+ ret = LONGT; /* check the authentication */
+ }
+ }
+ }
+ }
+ memset (pwd,0,MAILTMPLEN); /* erase password in case not overwritten */
+ if (!ret) *trial = 65535; /* don't retry if bad protocol */
+ return ret;
+}
+\f
+/* Server authenticator
+ * Accepts: responder function
+ * argument count
+ * argument vector
+ * Returns: authenticated user name or NIL
+ *
+ * This is much hairier than it needs to be due to the necessary of zapping
+ * the password data.
+ */
+
+static int md5try = MAXLOGINTRIALS;
+
+char *auth_md5_server (authresponse_t responder,int argc,char *argv[])
+{
+ char *ret = NIL;
+ char *p,*u,*user,*authuser,*hash,chal[MAILTMPLEN];
+ unsigned long cl,pl;
+ /* generate challenge */
+ sprintf (chal,"<%lu.%lu@%s>",(unsigned long) getpid (),
+ (unsigned long) time (0),mylocalhost ());
+ /* send challenge, get user and hash */
+ if (user = (*responder) (chal,cl = strlen (chal),NIL)) {
+ /* got user, locate hash */
+ if (hash = strrchr (user,' ')) {
+ *hash++ = '\0'; /* tie off user */
+ /* see if authentication user */
+ if (authuser = strchr (user,'*')) *authuser++ = '\0';
+ /* get password */
+ if (p = auth_md5_pwd ((authuser && *authuser) ? authuser : user)) {
+ pl = strlen (p);
+ u = (md5try && !strcmp (hash,hmac_md5 (chal,cl,p,pl))) ? user : NIL;
+ memset (p,0,pl); /* erase sensitive information */
+ fs_give ((void **) &p); /* flush erased password */
+ /* now log in for real */
+ if (u && authserver_login (u,authuser,argc,argv)) ret = myusername ();
+ else if (md5try) --md5try;
+ }
+ }
+ fs_give ((void **) &user);
+ }
+ if (!ret) sleep (3); /* slow down possible cracker */
+ return ret;
+}
+\f
+/* Return MD5 password for user
+ * Accepts: user name
+ * Returns: plaintext password if success, else NIL
+ *
+ * This is much hairier than it needs to be due to the necessary of zapping
+ * the password data. That's why we don't use stdio here.
+ */
+
+char *auth_md5_pwd (char *user)
+{
+ struct stat sbuf;
+ int fd = open (MD5ENABLE,O_RDONLY,NIL);
+ unsigned char *s,*t,*buf,*lusr,*lret;
+ char *r;
+ char *ret = NIL;
+ if (fd >= 0) { /* found the file? */
+ fstat (fd,&sbuf); /* yes, slurp it into memory */
+ read (fd,buf = (char *) fs_get (sbuf.st_size + 1),sbuf.st_size);
+ /* see if any uppercase characters in user */
+ for (s = user; *s && ((*s < 'A') || (*s > 'Z')); s++);
+ /* yes, make lowercase copy */
+ lusr = *s ? lcase (cpystr (user)) : NIL;
+ for (s = strtok_r ((char *) buf,"\015\012",&r),lret = NIL; s;
+ s = ret ? NIL : strtok_r (NIL,"\015\012",&r))
+ /* must be valid entry line */
+ if (*s && (*s != '#') && (t = strchr (s,'\t')) && t[1]) {
+ *t++ = '\0'; /* found tab, tie off user, point to pwd */
+ if (!strcmp (s,user)) ret = cpystr (t);
+ else if (lusr && !lret) if (!strcmp (s,lusr)) lret = t;
+ }
+ /* accept case-independent name */
+ if (!ret && lret) ret = cpystr (lret);
+ /* don't need lowercase copy any more */
+ if (lusr) fs_give ((void **) &lusr);
+ /* erase sensitive information from buffer */
+ memset (buf,0,sbuf.st_size + 1);
+ fs_give ((void **) &buf); /* flush the buffer */
+ close (fd); /* don't need file any longer */
+ }
+ return ret; /* return password */
+}
+\f
+/* APOP server login
+ * Accepts: challenge
+ * desired user name
+ * purported MD5
+ * argument count
+ * argument vector
+ * Returns: authenticated user name or NIL
+ */
+
+char *apop_login (char *chal,char *user,char *md5,int argc,char *argv[])
+{
+ int i,j;
+ char *ret = NIL;
+ char *s,*authuser,tmp[MAILTMPLEN];
+ unsigned char digest[MD5DIGLEN];
+ MD5CONTEXT ctx;
+ char *hex = "0123456789abcdef";
+ /* see if authentication user */
+ if (authuser = strchr (user,'*')) *authuser++ = '\0';
+ /* get password */
+ if (s = auth_md5_pwd ((authuser && *authuser) ? authuser : user)) {
+ md5_init (&ctx); /* initialize MD5 context */
+ /* build string to get MD5 digest */
+ sprintf (tmp,"%.128s%.128s",chal,s);
+ memset (s,0,strlen (s)); /* erase sensitive information */
+ fs_give ((void **) &s); /* flush erased password */
+ md5_update (&ctx,(unsigned char *) tmp,strlen (tmp));
+ memset (tmp,0,MAILTMPLEN); /* erase sensitive information */
+ md5_final (digest,&ctx);
+ /* convert to printable hex */
+ for (i = 0, s = tmp; i < MD5DIGLEN; i++) {
+ *s++ = hex[(j = digest[i]) >> 4];
+ *s++ = hex[j & 0xf];
+ }
+ *s = '\0'; /* tie off hash text */
+ memset (digest,0,MD5DIGLEN);/* erase sensitive information */
+ if (md5try && !strcmp (md5,tmp) &&
+ authserver_login (user,authuser,argc,argv))
+ ret = cpystr (myusername ());
+ else if (md5try) --md5try;
+ memset (tmp,0,MAILTMPLEN); /* erase sensitive information */
+ }
+ if (!ret) sleep (3); /* slow down possible cracker */
+ return ret;
+}
+\f
+/*
+ * RFC 2104 HMAC hashing
+ * Accepts: text to hash
+ * text length
+ * key
+ * key length
+ * Returns: hash as text, always
+ */
+
+char *hmac_md5 (char *text,unsigned long tl,char *key,unsigned long kl)
+{
+ int i,j;
+ static char hshbuf[2*MD5DIGLEN + 1];
+ char *s;
+ MD5CONTEXT ctx;
+ char *hex = "0123456789abcdef";
+ unsigned char digest[MD5DIGLEN],k_ipad[MD5BLKLEN+1],k_opad[MD5BLKLEN+1];
+ if (kl > MD5BLKLEN) { /* key longer than pad length? */
+ md5_init (&ctx); /* yes, set key as MD5(key) */
+ md5_update (&ctx,(unsigned char *) key,kl);
+ md5_final (digest,&ctx);
+ key = (char *) digest;
+ kl = MD5DIGLEN;
+ }
+ memcpy (k_ipad,key,kl); /* store key in pads */
+ memset (k_ipad+kl,0,(MD5BLKLEN+1)-kl);
+ memcpy (k_opad,k_ipad,MD5BLKLEN+1);
+ /* XOR key with ipad and opad values */
+ for (i = 0; i < MD5BLKLEN; i++) {
+ k_ipad[i] ^= 0x36;
+ k_opad[i] ^= 0x5c;
+ }
+ md5_init (&ctx); /* inner MD5: hash ipad and text */
+ md5_update (&ctx,k_ipad,MD5BLKLEN);
+ md5_update (&ctx,(unsigned char *) text,tl);
+ md5_final (digest,&ctx);
+ md5_init (&ctx); /* outer MD5: hash opad and inner results */
+ md5_update (&ctx,k_opad,MD5BLKLEN);
+ md5_update (&ctx,digest,MD5DIGLEN);
+ md5_final (digest,&ctx);
+ /* convert to printable hex */
+ for (i = 0, s = hshbuf; i < MD5DIGLEN; i++) {
+ *s++ = hex[(j = digest[i]) >> 4];
+ *s++ = hex[j & 0xf];
+ }
+ *s = '\0'; /* tie off hash text */
+ return hshbuf;
+}
+\f
+/* Everything after this point is derived from the RSA Data Security, Inc.
+ * MD5 Message-Digest Algorithm
+ */
+
+/* You may wonder why these strange "a &= 0xffffffff;" statements are here.
+ * This is to ensure correct results on machines with a unsigned long size of
+ * larger than 32 bits.
+ */
+
+#define RND1(a,b,c,d,x,s,ac) \
+ a += ((b & c) | (d & ~b)) + x + (unsigned long) ac; \
+ a &= 0xffffffff; \
+ a = b + ((a << s) | (a >> (32 - s)));
+
+#define RND2(a,b,c,d,x,s,ac) \
+ a += ((b & d) | (c & ~d)) + x + (unsigned long) ac; \
+ a &= 0xffffffff; \
+ a = b + ((a << s) | (a >> (32 - s)));
+
+#define RND3(a,b,c,d,x,s,ac) \
+ a += (b ^ c ^ d) + x + (unsigned long) ac; \
+ a &= 0xffffffff; \
+ a = b + ((a << s) | (a >> (32 - s)));
+
+#define RND4(a,b,c,d,x,s,ac) \
+ a += (c ^ (b | ~d)) + x + (unsigned long) ac; \
+ a &= 0xffffffff; \
+ a = b + ((a << s) | (a >> (32 - s)));
+\f
+/* Initialize MD5 context
+ * Accepts: context to initialize
+ */
+
+void md5_init (MD5CONTEXT *ctx)
+{
+ ctx->clow = ctx->chigh = 0; /* initialize byte count to zero */
+ /* initialization constants */
+ ctx->state[0] = 0x67452301; ctx->state[1] = 0xefcdab89;
+ ctx->state[2] = 0x98badcfe; ctx->state[3] = 0x10325476;
+ ctx->ptr = ctx->buf; /* reset buffer pointer */
+}
+
+
+/* MD5 add data to context
+ * Accepts: context
+ * input data
+ * length of data
+ */
+
+void md5_update (MD5CONTEXT *ctx,unsigned char *data,unsigned long len)
+{
+ unsigned long i = (ctx->buf + MD5BLKLEN) - ctx->ptr;
+ /* update double precision number of bytes */
+ if ((ctx->clow += len) < len) ctx->chigh++;
+ while (i <= len) { /* copy/transform data, 64 bytes at a time */
+ memcpy (ctx->ptr,data,i); /* fill up 64 byte chunk */
+ md5_transform (ctx->state,ctx->ptr = ctx->buf);
+ data += i,len -= i,i = MD5BLKLEN;
+ }
+ memcpy (ctx->ptr,data,len); /* copy final bit of data in buffer */
+ ctx->ptr += len; /* update buffer pointer */
+}
+\f
+/* MD5 Finalization
+ * Accepts: destination digest
+ * context
+ */
+
+void md5_final (unsigned char *digest,MD5CONTEXT *ctx)
+{
+ unsigned long i,bits[2];
+ bits[0] = ctx->clow << 3; /* calculate length in bits (before padding) */
+ bits[1] = (ctx->chigh << 3) + (ctx->clow >> 29);
+ *ctx->ptr++ = 0x80; /* padding byte */
+ if ((i = (ctx->buf + MD5BLKLEN) - ctx->ptr) < 8) {
+ memset (ctx->ptr,0,i); /* pad out buffer with zeros */
+ md5_transform (ctx->state,ctx->buf);
+ /* pad out with zeros, leaving 8 bytes */
+ memset (ctx->buf,0,MD5BLKLEN - 8);
+ ctx->ptr = ctx->buf + MD5BLKLEN - 8;
+ }
+ else if (i -= 8) { /* need to pad this buffer? */
+ memset (ctx->ptr,0,i); /* yes, pad out with zeros, leaving 8 bytes */
+ ctx->ptr += i;
+ }
+ md5_encode (ctx->ptr,bits,2); /* make LSB-first length */
+ md5_transform (ctx->state,ctx->buf);
+ /* store state in digest */
+ md5_encode (digest,ctx->state,4);
+ /* erase context */
+ memset (ctx,0,sizeof (MD5CONTEXT));
+}
+\f
+/* MD5 basic transformation
+ * Accepts: state vector
+ * current 64-byte block
+ */
+
+static void md5_transform (unsigned long *state,unsigned char *block)
+{
+ unsigned long a = state[0],b = state[1],c = state[2],d = state[3],x[16];
+ md5_decode (x,block,16); /* decode into 16 longs */
+ /* round 1 */
+ RND1 (a,b,c,d,x[ 0], 7,0xd76aa478); RND1 (d,a,b,c,x[ 1],12,0xe8c7b756);
+ RND1 (c,d,a,b,x[ 2],17,0x242070db); RND1 (b,c,d,a,x[ 3],22,0xc1bdceee);
+ RND1 (a,b,c,d,x[ 4], 7,0xf57c0faf); RND1 (d,a,b,c,x[ 5],12,0x4787c62a);
+ RND1 (c,d,a,b,x[ 6],17,0xa8304613); RND1 (b,c,d,a,x[ 7],22,0xfd469501);
+ RND1 (a,b,c,d,x[ 8], 7,0x698098d8); RND1 (d,a,b,c,x[ 9],12,0x8b44f7af);
+ RND1 (c,d,a,b,x[10],17,0xffff5bb1); RND1 (b,c,d,a,x[11],22,0x895cd7be);
+ RND1 (a,b,c,d,x[12], 7,0x6b901122); RND1 (d,a,b,c,x[13],12,0xfd987193);
+ RND1 (c,d,a,b,x[14],17,0xa679438e); RND1 (b,c,d,a,x[15],22,0x49b40821);
+ /* round 2 */
+ RND2 (a,b,c,d,x[ 1], 5,0xf61e2562); RND2 (d,a,b,c,x[ 6], 9,0xc040b340);
+ RND2 (c,d,a,b,x[11],14,0x265e5a51); RND2 (b,c,d,a,x[ 0],20,0xe9b6c7aa);
+ RND2 (a,b,c,d,x[ 5], 5,0xd62f105d); RND2 (d,a,b,c,x[10], 9, 0x2441453);
+ RND2 (c,d,a,b,x[15],14,0xd8a1e681); RND2 (b,c,d,a,x[ 4],20,0xe7d3fbc8);
+ RND2 (a,b,c,d,x[ 9], 5,0x21e1cde6); RND2 (d,a,b,c,x[14], 9,0xc33707d6);
+ RND2 (c,d,a,b,x[ 3],14,0xf4d50d87); RND2 (b,c,d,a,x[ 8],20,0x455a14ed);
+ RND2 (a,b,c,d,x[13], 5,0xa9e3e905); RND2 (d,a,b,c,x[ 2], 9,0xfcefa3f8);
+ RND2 (c,d,a,b,x[ 7],14,0x676f02d9); RND2 (b,c,d,a,x[12],20,0x8d2a4c8a);
+ /* round 3 */
+ RND3 (a,b,c,d,x[ 5], 4,0xfffa3942); RND3 (d,a,b,c,x[ 8],11,0x8771f681);
+ RND3 (c,d,a,b,x[11],16,0x6d9d6122); RND3 (b,c,d,a,x[14],23,0xfde5380c);
+ RND3 (a,b,c,d,x[ 1], 4,0xa4beea44); RND3 (d,a,b,c,x[ 4],11,0x4bdecfa9);
+ RND3 (c,d,a,b,x[ 7],16,0xf6bb4b60); RND3 (b,c,d,a,x[10],23,0xbebfbc70);
+ RND3 (a,b,c,d,x[13], 4,0x289b7ec6); RND3 (d,a,b,c,x[ 0],11,0xeaa127fa);
+ RND3 (c,d,a,b,x[ 3],16,0xd4ef3085); RND3 (b,c,d,a,x[ 6],23, 0x4881d05);
+ RND3 (a,b,c,d,x[ 9], 4,0xd9d4d039); RND3 (d,a,b,c,x[12],11,0xe6db99e5);
+ RND3 (c,d,a,b,x[15],16,0x1fa27cf8); RND3 (b,c,d,a,x[ 2],23,0xc4ac5665);
+ /* round 4 */
+ RND4 (a,b,c,d,x[ 0], 6,0xf4292244); RND4 (d,a,b,c,x[ 7],10,0x432aff97);
+ RND4 (c,d,a,b,x[14],15,0xab9423a7); RND4 (b,c,d,a,x[ 5],21,0xfc93a039);
+ RND4 (a,b,c,d,x[12], 6,0x655b59c3); RND4 (d,a,b,c,x[ 3],10,0x8f0ccc92);
+ RND4 (c,d,a,b,x[10],15,0xffeff47d); RND4 (b,c,d,a,x[ 1],21,0x85845dd1);
+ RND4 (a,b,c,d,x[ 8], 6,0x6fa87e4f); RND4 (d,a,b,c,x[15],10,0xfe2ce6e0);
+ RND4 (c,d,a,b,x[ 6],15,0xa3014314); RND4 (b,c,d,a,x[13],21,0x4e0811a1);
+ RND4 (a,b,c,d,x[ 4], 6,0xf7537e82); RND4 (d,a,b,c,x[11],10,0xbd3af235);
+ RND4 (c,d,a,b,x[ 2],15,0x2ad7d2bb); RND4 (b,c,d,a,x[ 9],21,0xeb86d391);
+ /* update state */
+ state[0] += a; state[1] += b; state[2] += c; state[3] += d;
+ memset (x,0,sizeof (x)); /* erase sensitive data */
+}
+\f
+/* You may wonder why these strange "& 0xff" maskings are here. This is to
+ * ensure correct results on machines with a char size of larger than 8 bits.
+ * For example, the KCC compiler on the PDP-10 uses 9-bit chars.
+ */
+
+/* MD5 encode unsigned long into LSB-first bytes
+ * Accepts: destination pointer
+ * source
+ * length of source
+ */
+
+static void md5_encode (unsigned char *dst,unsigned long *src,int len)
+{
+ int i;
+ for (i = 0; i < len; i++) {
+ *dst++ = (unsigned char) (src[i] & 0xff);
+ *dst++ = (unsigned char) ((src[i] >> 8) & 0xff);
+ *dst++ = (unsigned char) ((src[i] >> 16) & 0xff);
+ *dst++ = (unsigned char) ((src[i] >> 24) & 0xff);
+ }
+}
+
+
+/* MD5 decode LSB-first bytes into unsigned long
+ * Accepts: destination pointer
+ * source
+ * length of destination
+ */
+
+static void md5_decode (unsigned long *dst,unsigned char *src,int len)
+{
+ int i, j;
+ for (i = 0, j = 0; i < len; i++, j += 4)
+ dst[i] = ((unsigned long) (src[j] & 0xff)) |
+ (((unsigned long) (src[j+1] & 0xff)) << 8) |
+ (((unsigned long) (src[j+2] & 0xff)) << 16) |
+ (((unsigned long) (src[j+3] & 0xff)) << 24);
+}
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