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Prevent user from breaking his limits and restrictions or

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abusing sendmail by any other way via MAILTO tag (since sendmail is running
from daemon). Now run sendmail from user, as any other cron user command.

Obtained from:	Inspired by OpenBSD, but implementation is different
This commit is contained in:
Andrey A. Chernov 2000-07-01 22:58:16 +00:00
parent c38d808de1
commit fe46d6a8f3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=62367
3 changed files with 61 additions and 4 deletions
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2
usr.sbin/cron/cron/cron.h
View File

@ -237,7 +237,7 @@ user *load_user __P((int, struct passwd *, char *)),
entry *load_entry __P((FILE *, void (*)(),
struct passwd *, char **));
FILE *cron_popen __P((char *, char *));
FILE *cron_popen __P((char *, char *, entry *));
/* in the C tradition, we only create

4
usr.sbin/cron/cron/do_command.c
View File

@ -418,11 +418,11 @@ child_process(e, u)
(void) gethostname(hostname, MAXHOSTNAMELEN);
(void) snprintf(mailcmd, sizeof(mailcmd),
MAILARGS, MAILCMD);
if (!(mail = cron_popen(mailcmd, "w"))) {
if (!(mail = cron_popen(mailcmd, "w", e))) {
warn("%s", MAILCMD);
(void) _exit(ERROR_EXIT);
}
fprintf(mail, "From: root (Cron Daemon)\n");
fprintf(mail, "From: %s (Cron Daemon)\n", usernm);
fprintf(mail, "To: %s\n", mailto);
fprintf(mail, "Subject: Cron <%s@%s> %s\n",
usernm, first_word(hostname, "."),

59
usr.sbin/cron/cron/popen.c
View File

@ -34,6 +34,12 @@ static const char rcsid[] =
#include "cron.h"
#include <sys/signal.h>
#include <fcntl.h>
#if defined(SYSLOG)
# include <syslog.h>
#endif
#if defined(LOGIN_CAP)
# include <login_cap.h>
#endif
#define MAX_ARGS 100
@ -48,14 +54,20 @@ static PID_T *pids;
static int fds;
FILE *
cron_popen(program, type)
cron_popen(program, type, e)
char *program, *type;
entry *e;
{
register char *cp;
FILE *iop;
int argc, pdes[2];
PID_T pid;
char *usernm;
char *argv[MAX_ARGS + 1];
# if defined(LOGIN_CAP)
struct passwd *pwd;
login_cap_t *lc;
# endif
#if WANT_GLOBBING
char **pop, *vv[2];
int gargc;
@ -106,6 +118,15 @@ cron_popen(program, type)
goto pfree;
/* NOTREACHED */
case 0: /* child */
if (e != NULL) {
#ifdef SYSLOG
closelog();
#endif
/* get new pgrp, void tty, etc.
*/
(void) setsid();
}
if (*type == 'r') {
/* Do not share our parent's stdin */
(void)close(0);
@ -128,6 +149,42 @@ cron_popen(program, type)
(void)open("/dev/null", O_RDWR);
(void)close(pdes[1]);
}
# if defined(LOGIN_CAP)
if (e != NULL) {
/* Set user's entire context, but skip the environment
* as cron provides a separate interface for this
*/
usernm = env_get("LOGNAME", e->envp);
if ((pwd = getpwnam(usernm)) == NULL)
pwd = getpwuid(e->uid);
lc = NULL;
if (pwd != NULL) {
pwd->pw_gid = e->gid;
if (e->class != NULL)
lc = login_getclass(e->class);
}
if (pwd &&
setusercontext(lc, pwd, e->uid,
LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETENV)) == 0)
(void) endpwent();
else {
/* fall back to the old method */
(void) endpwent();
# endif
/* set our directory, uid and gid. Set gid first,
* since once we set uid, we've lost root privledges.
*/
setgid(e->gid);
# if defined(BSD)
initgroups(usernm, e->gid);
# endif
setlogin(usernm);
setuid(e->uid); /* we aren't root after this..*/
#if defined(LOGIN_CAP)
}
#endif
chdir(env_get("HOME", e->envp));
}
#if WANT_GLOBBING
execvp(gargv[0], gargv);
#else