caxmap.c

/*
 *  William Warnecke
 *  Backpack Software
 * 
 *  Courier Authpipe - Xmail Mailuserstab Authentication Program (CAXMAP)
 * 
 *  Version 1 - Release
 * 
 *  REFERENCES:
 *   - http://www.courier-mta.org/authlib/README_authlib.html
 *   - File Paths
 * 	maildir:	/xmail/MailRoot/domains/$domain/$user/Maildir/
 * 	authlib bins:	/usr/local/libexec/courier-authlib/
 * 	authlib libs:	/usr/local/lib/courier-authlib/
 * 	authlib conf:	/usr/local/etc/authlib/
 *	authProg:	/usr/local/etc/authlib/authProg
 *	courier main:	/usr/lib/courier-imap/
 *
 *  BUGS:
 *   - Getting garbage in sAuthData
 *
 *  TODO:
 *   - Change paths to be variables, or maybe ini file settings?
 *   - On the fly debugging levels?  standardize logging
 *   - Configure script or ?
 *   - hashmap for fast checking
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char *StrCrypt(char const * pszString, char *pszCourierCryptedPassword)
{
	/*
	 *  Xmail Crypt Function
	 */

	strcpy(pszCourierCryptedPassword, "");

	for (int ii = 0; pszString[ii] != '\0'; ii++) {
		signed int    uChar = (unsigned int) pszString[ii];
		char            szByte[32] = "";

		sprintf(szByte, "%02x", (uChar ^ 101) & 0xff);
		strcat(pszCourierCryptedPassword, szByte);
	}

	return (pszCourierCryptedPassword);
}


char *StrDeCrypt(char const *pszString, char *pszDeCrypt)
{
	/*
	 *  Xmail Decrypt Function
	 *  This is not currently used by this program
	 */

	int iStrLength = strlen(pszString);
	int ii;
	signed int uChar = 0;
	char szByte[8] = "";

	*pszDeCrypt = 0;

	if ((iStrLength % 2) != 0) {
		return (NULL);
	}


	for (ii = 0; ii < iStrLength; ii += 2) {
		szByte[0] = pszString[ii];
		szByte[1] = pszString[ii + 1];
		szByte[2] = '\0';

		if (sscanf(szByte, "%x", &uChar) != 1) {
			return (NULL);
		}

		pszDeCrypt[ii >> 1] = (char) ((uChar ^ 101) & 0xff);
	}

	pszDeCrypt[ii >> 1] = '\0';

	return (pszDeCrypt);

}


void main(int argc, char **argv)
{
	/*
	 *  file descriptors
	 */
	FILE *fdXmail;
	FILE *fdLog;

	/*
	 *  stdin buffer
	 */
	char szStdinBuffer[1024] = "";

	/*
	 *  all used when reading/manipulating xmails user mailtab
	 */
	char szXmailDomain[128];
	char szXmailUsername[128];
	char szXmailPassword[128];

	/*
	 *  holding junk
	 */
	char *lpUnused1;
	char *lpUnused2;

	/*
	 *  all used/populated by data that came from courier via stdin
	 *  this stuff is user supplied, so it's dirty.  may need to check
	 *  buffers?  dunno if the functions i used were vulnerable (don't think so :/)
	 */
	char *lpCourierFullUsername;

	char *lpCourierUsername;
	char szCourierQuotedUsername[128] = "";

	char *lpCourierPassword;
	char szCourierCryptedPassword[128] = "";
	char szCourierQuotedPassword[128] = "";

	char *lpCourierDomain;
	char szCourierQuotedDomain[128] = "";

	/*
	 *  -- Main --
	 */
	fdLog = fopen("/usr/home/wwarnecke/log","a");

	fprintf(fdLog,"started program\n");

	fgets(szStdinBuffer, 1024, stdin);
	fprintf(fdLog,"stdin: %s\n",szStdinBuffer);

	/*
	 *  after reading in stdin we should have either an AUTH, PRE, ENUMERATE,
	 *  or PASSWD command.  so far we've implmented AUTH and PRE
	 *  under each section is a commant for the format in which we'll receieve
	 *  stdin
	 */

	if(strstr(szStdinBuffer,"AUTH ")) {
		/* AUTH len<newline>len-bytes */

		int iAuthSize;

		/*
		 *  read stdin, and allocate buffer space
		 *  then read in len-bytes of auth data
		 */
		sscanf(szStdinBuffer,"%*s%d",&iAuthSize);
		fprintf(fdLog,"auth: '%d'\n",iAuthSize);

		char sAuthData[iAuthSize-1];

		fread(sAuthData,1,iAuthSize,stdin);
		fprintf(fdLog,"stdin:\n%s\n--\n",sAuthData); /* XXX getting garbage here :( */

		/*
		 *  split apart username/domain, if domain is null populate it
		 *  with a default (hardcoded at the momment)
		 *  also encrypt password, additionally quote everything because
		 *  it's all quoted in the xmail mailtab
		 */

		lpUnused1 = strtok(sAuthData,"\n"); /* unused 1 */
		lpUnused2 = strtok(NULL,"\n"); /* unused 2 */
		lpCourierFullUsername = strtok(NULL,"\n"); /* username@domain */
		lpCourierPassword = strtok(NULL,"\n"); /* password */

		lpCourierUsername = strtok(lpCourierFullUsername,"@"); /* username */
		lpCourierDomain = strtok(NULL,"@"); /* domain */

		if(lpCourierDomain == NULL) { lpCourierDomain = "winternet.com"; }

		fprintf(fdLog,"u: %s , d: %s , p: %s\n",lpCourierUsername,lpCourierDomain,lpCourierPassword);

		sprintf(szCourierQuotedUsername,"\"%s\"",lpCourierUsername); /* username - quoted */
		sprintf(szCourierQuotedDomain,"\"%s\"",lpCourierDomain); /* domain - quoted */

		StrCrypt(lpCourierPassword,szCourierCryptedPassword); /* password - encrypted */
		sprintf(szCourierQuotedPassword,"\"%s\"",szCourierCryptedPassword); /* password - encrypted and quoted */

                fdXmail = fopen("/xmail/MailRoot/mailusers.tab","rt");

		/*
		 *  read the file, loop on it.  add a hashmap in here in the future.
		 *  compared everything, if it matches return.  if not, when we exit loop we fail
		 */
                while(fscanf(fdXmail, "%s %s %s %*d %*s %*s",szXmailDomain,szXmailUsername,szXmailPassword) != EOF) {
                        if((strcmp(szXmailUsername,szCourierQuotedUsername) == 0) &&
                                (strcmp(szXmailPassword,szCourierQuotedPassword) == 0) &&
                                (strcmp(szXmailDomain,szCourierQuotedDomain) == 0)) {

					fprintf(stdout,"USERNAME=root\nUID=0\nGID=1\nHOME=/xmail/MailRoot/domains/%s/%s/\nADDRESS=%s\nNAME=%s\nMAILDIR=Maildir/\n.\n",lpCourierDomain,lpCourierUsername,lpCourierFullUsername,lpCourierFullUsername);
					return 0;
                        }
                }
                fclose(fdXmail);

		fprintf(stdout,"FAIL\n");
		return 0;
		
	} else if(strstr(szStdinBuffer,"PRE ")) {
		/* PRE . authservice username <newline> */

		/*
		 *  almost the same thing here as above, except no password magic
		 *  can read code comments above
		 */

		sscanf(szStdinBuffer,"%*s%*s%*s%s",lpCourierFullUsername);

                lpCourierUsername = strtok(lpCourierFullUsername,"@"); /* username */
                lpCourierDomain = strtok(NULL,"@"); /* domain */

                if(lpCourierDomain == NULL) { lpCourierDomain = "winternet.com"; }

                sprintf(szCourierQuotedUsername,"\"%s\"",lpCourierUsername); /* username - quoted */
                sprintf(szCourierQuotedDomain,"\"%s\"",lpCourierDomain); /* domain - quoted */

                fdXmail = fopen("/xmail/MailRoot/mailusers.tab","rt");

                while(fscanf(fdXmail, "%s %s %s %*d %*s %*s",szXmailDomain,szXmailUsername,szXmailPassword) != EOF) {
                        if((strcmp(szXmailUsername,szCourierQuotedUsername) == 0) &&
                                (strcmp(szXmailDomain,lpCourierDomain) == 0)) {

                                        fprintf(stdout,"USERNAME=root\nUID=0\nGID=1\nHOME=/xmail/MailRoot/domains/%s/%s/\nADDRESS=%s\nNAME=%s\nMAILDIR=Maildir/\n.\n",lpCourierDomain,lpCourierUsername,lpCourierFullUsername,lpCourierFullUsername);
                                        return 0;
                        }
                }
                fclose(fdXmail);

                fprintf(stdout,"FAIL\n");
                return 0;
		
	} else if(strstr(szStdinBuffer,"PASSWD ")) {
		/* PASSWD service<tab>  username<tab>  oldpasswd<tab>  newpasswd<tab>  <newline> */

		/* not yet implemented */

		fprintf(stdout,"FAIL\n");
		return 0;
	} else if(strstr(szStdinBuffer,"ENUMERATE ")) {
		/* ENUMERATE <newline> */

		/* not yet implemented */

		fprintf(stdout,".\n");
		return 0;
	} else {
		/*
		 *  if we didn't see anything we recognize from courier
		 *  we'll just fail.  program shouldn't be run from command line, etc
		 */

		fprintf(stdout,"FAIL\n");
		return 0;
	}

	fflush(fdLog);
	fclose(fdLog);

	fprintf(stdout,"FAIL\n");
	return 0;
}