apop.c

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

#include <unistd.h>
#include <time.h>
#include <pwd.h>

/* syslog by A. van Veen <Andre.C.VanVeen@ruhr-uni-bochum.de> 1999-04-11
/**************************************************************************/
#ifndef NO_SYSLOG
#include <syslog.h>
#endif
/**************************************************************************/
#include <sys/types.h>

#include "pop3.h"

/* added by Glynn Clements <glynn@sensei.co.uk> 1997-06-02 */

/**************************************************************************/

static char timestamp[256];
static int stamplen;

/**************************************************************************/

char *
apop_timestamp()
{
    time_t t;
    struct tm *tm;

    time(&t);
    tm = localtime(&t);
    strftime(timestamp, sizeof(timestamp), "<%a %b %d %H:%M:%S %Y>", tm);

    return timestamp;
}

/**************************************************************************/

/* Verify a usercode/password-hash */
int
verify_user_apop(user, pass)
char *user;
char *pass;
{
    char buff[1024];
    int userlen, passlen;
    FILE *fp;
    char *p, *q;
    struct passwd *pwd;

    for (p = user; *p; p++)
        *p = tolower(*p);
    userlen = p - user;

    pwd = getpwnam(user);
    if (!pwd) return -1;    /* User not found, return error */

    fp = fopen(APOP_PASSWORD_FILE, "r");
    if (!fp)
    {
#ifndef NO_SYSLOG
        syslog( SYSLOGPRI, "Could not open %s", APOP_PASSWORD_FILE);
#endif
        return -1;
    }

    while (1)
    {
        if (feof(fp))
        {
#ifndef NO_SYSLOG
            syslog( SYSLOGPRI, "User not found in %s: %s",
                APOP_PASSWORD_FILE, user);
#endif
            return -1;
        }

        fgets(buff, sizeof(buff), fp);
        if (strncmp(buff, user, userlen) != 0)
            continue;
        if (buff[userlen] != ':')
            continue;

        q = timestamp + strlen(timestamp);
        for (p = buff + userlen + 1; *p && *p != '\n'; p++, q++)
            *q = *p;
        passlen = q - timestamp;
        break;
    }
    fclose(fp);

    do_md5_string(timestamp, passlen, buff);
    if (strcmp(pass, buff) != 0) return -1;

    if (setuid(pwd->pw_uid) < 0)
    {
#ifndef NO_SYSLOG
        syslog( SYSLOGPRI, "[APOP]: Could not setuid()");
#endif
        return -1;
    }

    return 0;
}

/**************************************************************************/