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/*
* SPDX-FileCopyrightText: 1990 - 1994, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 2000, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2002 - 2005, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2007 - 2008, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <sys/types.h>
#include "defines.h"
#include "prototypes.h"
#ifndef SUAUTHFILE
#define SUAUTHFILE "/etc/suauth"
#endif
#define NOACTION 0
#define NOPWORD 1
#define DENY -1
#define OWNPWORD 2
#ifdef SU_ACCESS
/* Really, I could do with a few const char's here defining all the
* strings output to the user or the syslog. -- chris
*/
static int applies (const char *, char *);
static int isgrp (const char *, const char *);
static int lines = 0;
int check_su_auth (const char *actual_id,
const char *wanted_id,
bool su_to_root)
{
int posn, endline;
const char field[] = ":";
FILE *authfile_fd;
char temp[1024];
char *to_users;
char *from_users;
char *action;
if (!(authfile_fd = fopen (SUAUTHFILE, "r"))) {
int err = errno;
/*
* If the file doesn't exist - default to the standard su
* behaviour (no access control). If open fails for some
* other reason - maybe someone is trying to fool us with
* file descriptors limit etc., so deny access. --marekm
*/
if (ENOENT == err) {
return NOACTION;
}
SYSLOG ((LOG_ERR,
"could not open/read config file '%s': %s\n",
SUAUTHFILE, strerror (err)));
return DENY;
}
while (fgets (temp, sizeof (temp), authfile_fd) != NULL) {
lines++;
if (temp[endline = strlen (temp) - 1] != '\n') {
SYSLOG ((LOG_ERR,
"%s, line %d: line too long or missing newline",
SUAUTHFILE, lines));
continue;
}
while (endline > 0 && (temp[endline - 1] == ' '
|| temp[endline - 1] == '\t'
|| temp[endline - 1] == '\n'))
endline--;
temp[endline] = '\0';
posn = 0;
while (temp[posn] == ' ' || temp[posn] == '\t')
posn++;
if (temp[posn] == '\n' || temp[posn] == '#'
|| temp[posn] == '\0') {
continue;
}
if (!(to_users = strtok (temp + posn, field))
|| !(from_users = strtok ((char *) NULL, field))
|| !(action = strtok ((char *) NULL, field))
|| strtok ((char *) NULL, field)) {
SYSLOG ((LOG_ERR,
"%s, line %d. Bad number of fields.\n",
SUAUTHFILE, lines));
continue;
}
if (!applies (wanted_id, to_users))
continue;
if (!applies (actual_id, from_users))
continue;
if (!strcmp (action, "DENY")) {
SYSLOG ((su_to_root ? LOG_WARN : LOG_NOTICE,
"DENIED su from '%s' to '%s' (%s)\n",
actual_id, wanted_id, SUAUTHFILE));
fputs (_("Access to su to that account DENIED.\n"),
stderr);
fclose (authfile_fd);
return DENY;
} else if (!strcmp (action, "NOPASS")) {
SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO,
"NO password asked for su from '%s' to '%s' (%s)\n",
actual_id, wanted_id, SUAUTHFILE));
fputs (_("Password authentication bypassed.\n"),stderr);
fclose (authfile_fd);
return NOPWORD;
} else if (!strcmp (action, "OWNPASS")) {
SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO,
"su from '%s' to '%s': asking for user's own password (%s)\n",
actual_id, wanted_id, SUAUTHFILE));
fputs (_("Please enter your OWN password as authentication.\n"),
stderr);
fclose (authfile_fd);
return OWNPWORD;
} else {
SYSLOG ((LOG_ERR,
"%s, line %d: unrecognized action!\n",
SUAUTHFILE, lines));
}
}
fclose (authfile_fd);
return NOACTION;
}
static int applies (const char *single, char *list)
{
const char split[] = ", ";
char *tok;
int state = 0;
for (tok = strtok (list, split); tok != NULL;
tok = strtok (NULL, split)) {
if (!strcmp (tok, "ALL")) {
if (state != 0) {
SYSLOG ((LOG_ERR,
"%s, line %d: ALL in bad place\n",
SUAUTHFILE, lines));
return 0;
}
state = 1;
} else if (!strcmp (tok, "EXCEPT")) {
if (state != 1) {
SYSLOG ((LOG_ERR,
"%s, line %d: EXCEPT in bas place\n",
SUAUTHFILE, lines));
return 0;
}
state = 2;
} else if (!strcmp (tok, "GROUP")) {
if ((state != 0) && (state != 2)) {
SYSLOG ((LOG_ERR,
"%s, line %d: GROUP in bad place\n",
SUAUTHFILE, lines));
return 0;
}
state = (state == 0) ? 3 : 4;
} else {
switch (state) {
case 0: /* No control words yet */
if (!strcmp (tok, single))
return 1;
break;
case 1: /* An all */
SYSLOG ((LOG_ERR,
"%s, line %d: expect another token after ALL\n",
SUAUTHFILE, lines));
return 0;
case 2: /* All except */
if (!strcmp (tok, single))
return 0;
break;
case 3: /* Group */
if (isgrp (single, tok))
return 1;
break;
case 4: /* All except group */
if (isgrp (single, tok))
return 0;
/* FALL THRU */
}
}
}
if ((state != 0) && (state != 3))
return 1;
return 0;
}
static int isgrp (const char *name, const char *group)
{
struct group *grp;
grp = getgrnam (group); /* local, no need for xgetgrnam */
if (!grp || !grp->gr_mem)
return 0;
return is_on_list (grp->gr_mem, name);
}
#endif /* SU_ACCESS */
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