source: bootcd/isolinux/syslinux-6.03/com32/cmenu/libmenu/passwords.c

/* -*- c -*- ------------------------------------------------------------- *
 *
 *   Copyright 2004-2005 Murali Krishnan Ganapathy - All Rights Reserved
 *
 *   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, Inc., 53 Temple Place Ste 330,
 *   Bostom MA 02111-1307, USA; either version 2 of the License, or
 *   (at your option) any later version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

#include "passwords.h"
#include "des.h"
#include "string.h"
#include <stdlib.h>
#include <stdio.h>
#include "tui.h"

#define MAX_LINE 512
// Max line length in a pwdfile
p_pwdentry userdb[MAX_USERS];   // Array of pointers
int numusers;                   // Actual number of users

// returns true or false, i.e. 1 or 0
char authenticate_user(const char *username, const char *pwd)
{
    char salt[12];
    int i;

    for (i = 0; i < numusers; i++) {
        if (userdb[i] == NULL)
            continue;
        if (strcmp(username, userdb[i]->username) == 0) {
            strcpy(salt, userdb[i]->pwdhash);
            salt[2] = '\0';
            if (strcmp(userdb[i]->pwdhash, crypt(pwd, salt)) == 0)
                return 1;
        }
    }
    return 0;
}

// Does user USERNAME  have permission PERM
char isallowed(const char *username, const char *perm)
{
    int i;
    char *dperm;
    char *tmp;

    // If no users, then everybody is allowed to do everything
    if (numusers == 0)
        return 1;
    if (strcmp(username, GUEST_USER) == 0)
        return 0;
    dperm = (char *)malloc(strlen(perm) + 3);
    strcpy(dperm + 1, perm);
    dperm[0] = ':';
    dperm[strlen(perm) + 1] = ':';
    dperm[strlen(perm) + 2] = 0;
    // Now dperm = ":perm:"
    for (i = 0; i < numusers; i++) {
        if (strcmp(userdb[i]->username, username) == 0) // Found the user
        {
            if (userdb[i]->perms == NULL)
                return 0;       // No permission
            tmp = strstr(userdb[i]->perms, dperm);      // Search for permission
            free(dperm);        // Release memory
            if (tmp == NULL)
                return 0;
            else
                return 1;
        }
    }
    // User not found return 0
    free(dperm);
    return 0;
}

// Initialise the list of of user passwords permissions from file
void init_passwords(const char *filename)
{
    int i;
    char line[MAX_LINE], *p, *user, *pwdhash, *perms;
    FILE *f;

    for (i = 0; i < MAX_USERS; i++)
        userdb[i] = NULL;
    numusers = 0;

    if (!filename)
        return;                 // No filename specified

    f = fopen(filename, "r");
    if (!f)
        return;                 // File does not exist

    // Process each line
    while (fgets(line, sizeof line, f)) {
        // Replace EOLN with \0
        p = strchr(line, '\r');
        if (p)
            *p = '\0';
        p = strchr(line, '\n');
        if (p)
            *p = '\0';

        // If comment line or empty ignore line
        p = line;
        while (*p == ' ')
            p++;                // skip initial spaces
        if ((*p == '#') || (*p == '\0'))
            continue;           // Skip comment lines

        user = p;               // This is where username starts
        p = strchr(user, ':');
        if (p == NULL)
            continue;           // Malformed line skip
        *p = '\0';
        pwdhash = p + 1;
        if (*pwdhash == 0)
            continue;           // Malformed line (no password specified)
        p = strchr(pwdhash, ':');
        if (p == NULL) {        // No perms specified
            perms = NULL;
        } else {
            *p = '\0';
            perms = p + 1;
            if (*perms == 0)
                perms = NULL;
        }
        // At this point we have user,pwdhash and perms setup
        userdb[numusers] = (p_pwdentry) malloc(sizeof(pwdentry));
        strcpy(userdb[numusers]->username, user);
        strcpy(userdb[numusers]->pwdhash, pwdhash);
        if (perms == NULL)
            userdb[numusers]->perms = NULL;
        else {
            userdb[numusers]->perms = (char *)malloc(strlen(perms) + 3);
            (userdb[numusers]->perms)[0] = ':';
            strcpy(userdb[numusers]->perms + 1, perms);
            (userdb[numusers]->perms)[strlen(perms) + 1] = ':';
            (userdb[numusers]->perms)[strlen(perms) + 2] = 0;
            // Now perms field points to ":perms:"
        }
        numusers++;
    }
    fclose(f);
}

void close_passwords(void)
{
    int i;

    for (i = 0; i < numusers; i++)
        if (userdb[i] != NULL)
            free(userdb[i]);
    numusers = 0;
}