File: [local] / src / usr.bin / sudo / Attic / visudo.c (download)
Revision 1.7, Fri Dec 15 04:10:13 2000 UTC (23 years, 6 months ago) by millert
Branch: MAIN
Changes since 1.6: +1 -1 lines
'Q' means ignore parse error, not 'q'
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/*
* Copyright (c) 1996, 1998-2000 Todd C. Miller <Todd.Miller@courtesan.com>
* All rights reserved.
*
* 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. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 4. Products derived from this software may not be called "Sudo" nor
* may "Sudo" appear in their names without specific prior written
* permission from the author.
*
* THIS SOFTWARE IS PROVIDED ``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 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,
* WHETHER 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.
*/
/*
* Lock the sudoers file for safe editing (ala vipw) and check for parse errors.
*/
#include "config.h"
#include <stdio.h>
#ifdef STDC_HEADERS
#include <stdlib.h>
#endif /* STDC_HEADERS */
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif /* HAVE_STRINGS_H */
#if defined(HAVE_MALLOC_H) && !defined(STDC_HEADERS)
#include <malloc.h>
#endif /* HAVE_MALLOC_H && !STDC_HEADERS */
#include <ctype.h>
#include <pwd.h>
#include <time.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/file.h>
#include "sudo.h"
#include "version.h"
#ifndef STDC_HEADERS
#ifndef __GNUC__ /* gcc has its own malloc */
extern char *malloc __P((size_t));
#endif /* __GNUC__ */
extern char *getenv __P((const char *));
extern int stat __P((const char *, struct stat *));
#endif /* !STDC_HEADERS */
#if defined(POSIX_SIGNALS) && !defined(SA_RESETHAND)
#define SA_RESETHAND 0
#endif /* POSIX_SIGNALS && !SA_RESETHAND */
#ifndef lint
static const char rcsid[] = "$Sudo: visudo.c,v 1.126 2000/03/23 04:38:22 millert Exp $";
#endif /* lint */
/*
* Function prototypes
*/
static void usage __P((void));
static char whatnow __P((void));
static RETSIGTYPE Exit __P((int));
static void setup_signals __P((void));
int command_matches __P((char *, char *, char *, char *));
int addr_matches __P((char *));
int hostname_matches __P((char *, char *, char *));
int netgr_matches __P((char *, char *, char *, char *));
int usergr_matches __P((char *, char *));
void init_parser __P((void));
void yyrestart __P((FILE *));
/*
* External globals exported by the parser
*/
extern FILE *yyin, *yyout;
extern int errorlineno;
extern int pedantic;
/*
* Globals
*/
char **Argv;
char *sudoers = _PATH_SUDOERS;
char *stmp = _PATH_SUDOERS_TMP;
struct sudo_user sudo_user;
int parse_error = FALSE;
int
main(argc, argv)
int argc;
char **argv;
{
char buf[MAXPATHLEN*2]; /* buffer used for copying files */
char *Editor; /* editor to use */
int sudoers_fd; /* sudoers file descriptor */
int stmp_fd; /* stmp file descriptor */
int n; /* length parameter */
time_t now; /* time now */
struct stat stmp_sb, sudoers_sb; /* to check for changes */
/* Warn about aliases that are used before being defined. */
pedantic = 1;
/*
* Parse command line options
*/
Argv = argv;
/*
* Arg handling.
*/
while (--argc) {
if (!strcmp(argv[argc], "-V")) {
(void) printf("visudo version %s\n", version);
exit(0);
} else if (!strcmp(argv[argc], "-s")) {
pedantic++; /* strict mode */
} else {
usage();
}
}
/* Mock up a fake sudo_user struct. */
user_host = user_shost = user_cmnd = "";
if ((sudo_user.pw = getpwuid(getuid())) == NULL) {
(void) fprintf(stderr, "%s: Can't find you in the passwd database.\n",
Argv[0]);
exit(1);
}
/* Setup defaults data structures. */
init_defaults();
/*
* Open sudoers, lock it and stat it.
* sudoers_fd must remain open throughout in order to hold the lock.
*/
sudoers_fd = open(sudoers, O_RDWR | O_CREAT, SUDOERS_MODE);
if (sudoers_fd == -1) {
(void) fprintf(stderr, "%s: %s: %s\n", Argv[0], sudoers,
strerror(errno));
Exit(-1);
}
if (!lock_file(sudoers_fd, SUDO_TLOCK)) {
(void) fprintf(stderr, "%s: sudoers file busy, try again later.\n",
Argv[0]);
exit(1);
}
#ifdef HAVE_FSTAT
if (fstat(sudoers_fd, &sudoers_sb) == -1) {
#else
if (stat(sudoers, &sudoers_sb) == -1) {
#endif
(void) fprintf(stderr, "%s: can't stat %s: %s\n",
Argv[0], sudoers, strerror(errno));
Exit(-1);
}
/*
* Open sudoers temp file.
*/
stmp_fd = open(stmp, O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (stmp_fd < 0) {
(void) fprintf(stderr, "%s: %s: %s\n", Argv[0], stmp, strerror(errno));
exit(1);
}
/* Install signal handlers to clean up stmp if we are killed. */
setup_signals();
/* Copy sudoers -> stmp and reset the mtime */
if (sudoers_sb.st_size) {
while ((n = read(sudoers_fd, buf, sizeof(buf))) > 0)
if (write(stmp_fd, buf, n) != n) {
(void) fprintf(stderr, "%s: Write failed: %s\n", Argv[0],
strerror(errno));
Exit(-1);
}
(void) close(stmp_fd);
(void) touch(stmp, sudoers_sb.st_mtime);
/* Parse sudoers to pull in editor and env_editor conf values. */
if ((yyin = fopen(stmp, "r"))) {
yyout = stdout;
init_parser();
yyparse();
parse_error = FALSE;
yyrestart(yyin);
fclose(yyin);
}
} else
(void) close(stmp_fd);
/*
* If we are allowing EDITOR and VISUAL envariables set Editor
* base on whichever exists...
*/
if (!def_flag(I_ENV_EDITOR) ||
(!(Editor = getenv("EDITOR")) && !(Editor = getenv("VISUAL"))))
Editor = estrdup(def_str(I_EDITOR));
/*
* Edit the temp file and parse it (for sanity checking)
*/
do {
/*
* Build up a buffer to execute
*/
if (strlen(Editor) + strlen(stmp) + 30 > sizeof(buf)) {
(void) fprintf(stderr, "%s: Buffer too short (line %d).\n",
Argv[0], __LINE__);
Exit(-1);
}
if (parse_error == TRUE)
(void) sprintf(buf, "%s +%d %s", Editor, errorlineno, stmp);
else
(void) sprintf(buf, "%s %s", Editor, stmp);
/* Do the edit -- some SYSV editors exit with 1 instead of 0 */
now = time(NULL);
n = system(buf);
if (n != -1 && ((n >> 8) == 0 || (n >> 8) == 1)) {
/*
* Sanity checks.
*/
if (stat(stmp, &stmp_sb) < 0) {
(void) fprintf(stderr,
"%s: Can't stat temporary file (%s), %s unchanged.\n",
Argv[0], stmp, sudoers);
Exit(-1);
}
if (stmp_sb.st_size == 0) {
(void) fprintf(stderr,
"%s: Zero length temporary file (%s), %s unchanged.\n",
Argv[0], stmp, sudoers);
Exit(-1);
}
/*
* Passed sanity checks so reopen stmp file and check
* for parse errors.
*/
yyout = stdout;
if (parse_error)
yyin = freopen(stmp, "r", yyin);
else
yyin = fopen(stmp, "r");
if (yyin == NULL) {
(void) fprintf(stderr,
"%s: Can't re-open temporary file (%s), %s unchanged.\n",
Argv[0], stmp, sudoers);
Exit(-1);
}
/* Clean slate for each parse */
user_runas = NULL;
init_defaults();
init_parser();
/* Parse the sudoers file */
if (yyparse() && parse_error != TRUE) {
(void) fprintf(stderr,
"%s: Failed to parse temporary file (%s), unknown error.\n",
Argv[0], stmp);
parse_error = TRUE;
}
} else {
(void) fprintf(stderr,
"%s: Editor (%s) failed with exit status %d, %s unchanged.\n",
Argv[0], Editor, n, sudoers);
Exit(-1);
}
/*
* Got an error, prompt the user for what to do now
*/
if (parse_error == TRUE) {
switch (whatnow()) {
case 'Q' : parse_error = FALSE; /* ignore parse error */
break;
case 'x' : Exit(0);
break;
}
yyrestart(yyin); /* reset lexer */
}
} while (parse_error == TRUE);
/*
* If the user didn't change the temp file, just unlink it.
*/
if (sudoers_sb.st_mtime != now && sudoers_sb.st_mtime == stmp_sb.st_mtime &&
sudoers_sb.st_size == stmp_sb.st_size) {
(void) fprintf(stderr, "%s: sudoers file unchanged.\n", Argv[0]);
Exit(0);
}
/*
* Change mode and ownership of temp file so when
* we move it to sudoers things are kosher.
*/
if (chown(stmp, SUDOERS_UID, SUDOERS_GID)) {
(void) fprintf(stderr,
"%s: Unable to set (uid, gid) of %s to (%d, %d): %s\n",
Argv[0], stmp, SUDOERS_UID, SUDOERS_GID, strerror(errno));
Exit(-1);
}
if (chmod(stmp, SUDOERS_MODE)) {
(void) fprintf(stderr,
"%s: Unable to change mode of %s to %o: %s\n",
Argv[0], stmp, SUDOERS_MODE, strerror(errno));
Exit(-1);
}
/*
* Now that we have a sane stmp file (parses ok) it needs to be
* rename(2)'d to sudoers. If the rename(2) fails we try using
* mv(1) in case stmp and sudoers are on different filesystems.
*/
if (rename(stmp, sudoers)) {
if (errno == EXDEV) {
char *tmpbuf;
(void) fprintf(stderr,
"%s: %s and %s not on the same filesystem, using mv to rename.\n",
Argv[0], stmp, sudoers);
/* Allocate just enough space for tmpbuf */
n = sizeof(char) * (strlen(_PATH_MV) + strlen(stmp) +
strlen(sudoers) + 4);
if ((tmpbuf = (char *) malloc(n)) == NULL) {
(void) fprintf(stderr,
"%s: Cannot alocate memory, %s unchanged: %s\n",
Argv[0], sudoers, strerror(errno));
Exit(-1);
}
/* Build up command and execute it */
(void) sprintf(tmpbuf, "%s %s %s", _PATH_MV, stmp, sudoers);
if (system(tmpbuf)) {
(void) fprintf(stderr,
"%s: Command failed: '%s', %s unchanged.\n",
Argv[0], tmpbuf, sudoers);
Exit(-1);
}
free(tmpbuf);
} else {
(void) fprintf(stderr, "%s: Error renaming %s, %s unchanged: %s\n",
Argv[0], stmp, sudoers, strerror(errno));
Exit(-1);
}
}
exit(0);
}
/*
* Dummy *_matches routines.
* These exist to allow us to use the same parser as sudo(8).
*/
int
command_matches(cmnd, cmnd_args, path, sudoers_args)
char *cmnd;
char *cmnd_args;
char *path;
char *sudoers_args;
{
return(TRUE);
}
int
addr_matches(n)
char *n;
{
return(TRUE);
}
int
hostname_matches(s, l, p)
char *s, *l, *p;
{
return(TRUE);
}
int
usergr_matches(g, u)
char *g, *u;
{
return(TRUE);
}
int
netgr_matches(n, h, sh, u)
char *n, *h, *sh, *u;
{
return(TRUE);
}
void
set_fqdn()
{
return;
}
/*
* Assuming a parse error occurred, prompt the user for what they want
* to do now. Returns the first letter of their choice.
*/
static char
whatnow()
{
int choice, c;
for (;;) {
(void) fputs("What now? ", stdout);
choice = getchar();
for (c = choice; c != '\n' && c != EOF;)
c = getchar();
switch (choice) {
case EOF:
choice = 'x';
/* FALLTHROUGH */
case 'e':
case 'x':
case 'Q':
return(choice);
default:
(void) puts("Options are:");
(void) puts(" (e)dit sudoers file again");
(void) puts(" e(x)it without saving changes to sudoers file");
(void) puts(" (Q)uit and save changes to sudoers file (DANGER!)\n");
}
}
}
/*
* Install signal handlers for visudo.
*/
static void
setup_signals()
{
#ifdef POSIX_SIGNALS
struct sigaction action; /* POSIX signal structure */
#endif /* POSIX_SIGNALS */
/*
* Setup signal handlers to cleanup nicely.
*/
#ifdef POSIX_SIGNALS
(void) memset((VOID *)&action, 0, sizeof(action));
action.sa_handler = Exit;
action.sa_flags = SA_RESETHAND;
(void) sigaction(SIGTERM, &action, NULL);
(void) sigaction(SIGHUP, &action, NULL);
(void) sigaction(SIGINT, &action, NULL);
(void) sigaction(SIGQUIT, &action, NULL);
#else
(void) signal(SIGTERM, Exit);
(void) signal(SIGHUP, Exit);
(void) signal(SIGINT, Exit);
(void) signal(SIGQUIT, Exit);
#endif /* POSIX_SIGNALS */
}
/*
* Unlink the sudoers temp file (if it exists) and exit.
* Used in place of a normal exit() and as a signal handler.
* A positive parameter is considered to be a signal and is reported.
*/
static RETSIGTYPE
Exit(sig)
int sig;
{
(void) unlink(stmp);
if (sig > 0)
(void) fprintf(stderr, "%s exiting, caught signal %d.\n", Argv[0], sig);
exit(-sig);
}
static void
usage()
{
(void) fprintf(stderr, "usage: %s [-s] [-V]\n", Argv[0]);
exit(1);
}