/*-
* perm.c - check user permission for at(1)
*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (C) 1994 Thomas Koenig
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the author(s) may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
/* System Headers */
#include <sys/types.h>
#include <err.h>
#include <errno.h>
#include <pwd.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* Local headers */
#include "at.h"
#include "perm.h"
#include "privs.h"
/* Macros */
#define MAXUSERID 10
/* Structures and unions */
/* Function declarations */
static int check_for_user(FILE *fp,const char *name);
/* Local functions */
static int check_for_user(FILE *fp,const char *name)
{
char *buffer;
size_t len;
int found = 0;
len = strlen(name);
if ((buffer = malloc(len+2)) == NULL)
errx(EXIT_FAILURE, "virtual memory exhausted");
while(fgets(buffer, len+2, fp) != NULL)
{
if ((strncmp(name, buffer, len) == 0) &&
(buffer[len] == '\n'))
{
found = 1;
break;
}
}
fclose(fp);
free(buffer);
return found;
}
/* Global functions */
int check_permission(void)
{
FILE *fp;
uid_t uid = geteuid();
struct passwd *pentry;
if (uid==0)
return 1;
if ((pentry = getpwuid(uid)) == NULL)
err(EXIT_FAILURE, "cannot access user database");
PRIV_START
fp=fopen(PERM_PATH "at.allow","r");
PRIV_END
if (fp != NULL)
{
return check_for_user(fp, pentry->pw_name);
}
else if (errno == ENOENT)
{
PRIV_START
fp=fopen(PERM_PATH "at.deny", "r");
PRIV_END
if (fp != NULL)
{
return !check_for_user(fp, pentry->pw_name);
}
else if (errno != ENOENT)
warn("at.deny");
}
else
warn("at.allow");
return 0;
}
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