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/*
* CFINGERD
* Parsing routines
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 1, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "cfingerd.h"
#include "proto.h"
/*
* SEARCH_ILLEGAL
*
* This searches for any illegal characters in a user's name. If there are
* any found, it returns a U_ILLEGAL, otherwise it returns a 0.
*/
int search_illegal(char *str)
{
int i;
if (str != NULL) {
for (i = 0; i < strlen(str); i++)
if (str[i] == '@')
return U_FORWARD;
else if (!isalpha(str[i]) && !isdigit(str[i]) && (str[i] != '.') &&
(str[i] != '_') && (str[i] != '-') && (str[i] != ',') &&
(str[i] != '?') && (str[i] != '*') && (str[i] != '/'))
return U_ILLEGAL;
}
return 0;
}
/*
* INTERNAL_CHECK
*
* This checks the username up against an internal username template,
* for use with cfingerd testing, debugging, and/or other information
* retrieval. Please don't disable this routine - this should be
* included with all of the cfingerd distributions.
*
* Returns U_INTERNAL if the username matches an internal username,
* otherwise, it returns a 0.
*/
int internal_check(char *username)
{
int length = strlen(username);
if (!strncmp(username, "version", 7) && length == 7 &&
prog_config.config_bits3 & SHOW_CONFESSION)
return(U_INTERNAL);
else if (!strncmp(username, "help", 4) && length == 4 &&
prog_config.config_bits3 & SHOW_CONFESSION)
return(U_INTERNAL);
else if (!strncmp(username, "services", 8) && length == 8 &&
prog_config.config_bits3 & SHOW_FAKEUSER)
return(U_INTERNAL);
else if (!strncmp(username, "search", 6) &&
prog_config.config_bits2 & SHOW_SEARCHFING)
return(U_INTERNAL);
else if (((!strncmp(username, "userlist-only", 13) && length == 13)
|| (!strncmp(username, "userlist-online", 15) && length == 15))
&& (prog_config.config_bits2 & SHOW_ULISTONLY) &&
((local_finger && prog_config.local_config_bits2 & SHOW_SYSTEMLIST) ||
(!local_finger && prog_config.config_bits2 & SHOW_SYSTEMLIST)))
return(U_INTERNAL);
return(0);
}
/*
* SEARCH_FAKE
*
* Search for a fake user. Returns U_FAKEUSER if the user is fake, and
* 0 if it is not.
*/
int search_fake(char *username)
{
char *parsed;
char *cp;
if ((cp = index (username, '.')) != NULL)
*cp='\0';
if ((parsed = (char *)malloc (strlen(username)+1)) != NULL) {
memset (parsed, 0, strlen(username)+1);
strcpy (parsed, username);
}
if (cp != NULL)
*cp='.';
if (parsed != NULL) {
if (search_fake_pos(parsed) >= 0) {
free (parsed);
return(U_FAKEUSER);
}
}
if (parsed) free (parsed);
return(0);
}
/*
* PROCESS_USERNAME
*
* This is the grand-daddy of them all. This routine does all of the
* sanity checks against the username to make sure it's a legal username.
* If the username doesn't exist, it returns the proper error message
* back to the user, and skips the finger-query request altogether. Other-
* wise, it returns:
*
* U_ILLEGAL: Username was illegal in checking
* U_FORWARD: Username is a forward request (contains `@')
* U_STANDARD: Username is a standard (non-fake) username
* U_FAKEUSER: Username matches a fake user
* U_INTERNAL: Username matches an internal (defined) username
* U_USERLIST: Username is not present - it's a userlisting
*/
int process_username(char *username)
{
int ret = 0;
if ((username[0] == 13) || (username[0] == 10) ||
(username[1] == 13) || (username[1] == 10))
ret = U_USERLIST;
else if (!strncmp (username, "userlist", 8) && strlen (username) == 8)
ret = U_USERLIST;
if (ret != U_USERLIST) {
ret = search_illegal(username);
if (ret == U_FORWARD) {
printf("%s\n", prog_config.p_strings[D_FORWARD_DENY]);
fflush(stdout);
mylog(LOG_USER, "Denied forward: ", username);
exit(1);
}
if (ret == U_ILLEGAL) {
printf("Illegal character in username.\n");
fflush(stdout);
mylog(LOG_USER, "Illegal: ", username);
exit(1);
}
ret = internal_check(username);
if (ret != U_INTERNAL)
ret = search_fake(username);
if (ret == 0)
ret = U_STANDARD;
}
return(ret);
}
/*
* Local variables:
* c-indent-level: 4
* c-basic-offset: 4
* tab-width: 8
* End:
*/
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