From 1bb8ac6c3c3f43df4c4f8fd89d69916e98f1f908 Mon Sep 17 00:00:00 2001 From: ache Date: Wed, 12 Apr 1995 02:52:21 +0000 Subject: Upgrade. Close security holes reported. --- libexec/atrun/Makefile | 24 +- libexec/atrun/atrun.c | 568 ++++++++++++++++++++++++++++-------------------- libexec/atrun/atrun.man | 66 ++++++ 3 files changed, 419 insertions(+), 239 deletions(-) create mode 100644 libexec/atrun/atrun.man (limited to 'libexec') diff --git a/libexec/atrun/Makefile b/libexec/atrun/Makefile index 27b8ea3..cb69fd1 100644 --- a/libexec/atrun/Makefile +++ b/libexec/atrun/Makefile @@ -1,13 +1,25 @@ -# $Id: Makefile,v 1.2 1993/12/05 12:26:10 cgd Exp $ +# $Id: Makefile,v 1.1 1994/01/05 01:02:56 nate Exp $ + +MAINSRC= ${.CURDIR}/../../usr.bin/at + +.include "$(MAINSRC)/Makefile.inc" PROG= atrun MAN8= atrun.8 -BINDIR= /usr/libexec -BINOWN= root +BINDIR= $(ATLIB_DIR) +MANSRC= . +CLEANFILES += ${MAN8} +MANDEPEND = ${MAN8} + +CFLAGS+= -I$(MAINSRC) -CFLAGS+= -I${.CURDIR}/../../usr.bin/at -LDADD+= -lutil -DPADD+= ${LIBUTIL} +${MAN8}: atrun.man + sed -e \ + "s@_ATSPOOL_DIR@$(ATSPOOL_DIR)@g; \ + s@_ATJOB_DIR@$(ATJOB_DIR)@g; \ + s@_ATLIB_DIR@$(ATLIB_DIR)@g; \ + s@_LOADAVG_MX@$(LOADAVG_MX)@g;" \ + < $? > $@ .include diff --git a/libexec/atrun/atrun.c b/libexec/atrun/atrun.c index 3b84ec9..4ab933d 100644 --- a/libexec/atrun/atrun.c +++ b/libexec/atrun/atrun.c @@ -1,7 +1,6 @@ -/* - * atrun.c - run jobs queued by at; run with root privileges. - * Copyright (c) 1993 by Thomas Koenig - * All rights reserved. +/* + * atrun.c - run jobs queued by at; run with root privileges. + * Copyright (C) 1993, 1994 Thomas Koenig * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -30,9 +29,11 @@ #include #include #include +#include #include #include #include +#include #include #include #include @@ -41,287 +42,388 @@ #include #include #include - +#ifndef __FreeBSD__ +#include +#else #include +#endif /* Local headers */ +#ifndef __FreeBSD__ +#include "gloadavg.h" +#endif #define MAIN #include "privs.h" -#include "pathnames.h" -#include "atrun.h" + +/* Macros */ + +#ifndef ATJOB_DIR +#define ATJOB_DIR "/usr/spool/atjobs/" +#endif + +#ifndef ATSPOOL_DIR +#define ATSPOOL_DIR "/usr/spool/atspool/" +#endif + +#ifndef LOADAVG_MX +#define LOADAVG_MX 1.5 +#endif /* File scope variables */ static char *namep; -static char rcsid[] = "$Id: atrun.c,v 1.1 1993/12/05 11:36:38 cgd Exp $"; +static char rcsid[] = "$Id: atrun.c,v 1.1 1994/05/10 18:23:08 kernel Exp $"; +static debug = 0; /* Local functions */ static void -perr(a) - const char *a; +perr(const char *a) { + if (debug) + { + perror(a); + } + else syslog(LOG_ERR, "%s: %m", a); - exit(EXIT_FAILURE); + + exit(EXIT_FAILURE); } static int -write_string(fd, a) - int fd; - const char *a; +write_string(int fd, const char* a) { - return write(fd, a, strlen(a)); + return write(fd, a, strlen(a)); } -static void -run_file(filename, uid, gid) - const char *filename; - uid_t uid; - gid_t gid; +#ifdef DEBUG_FORK +static pid_t +myfork() { - /* - * Run a file by by spawning off a process which redirects I/O, - * spawns a subshell, then waits for it to complete and spawns another - * process to send mail to the user. - */ - pid_t pid; - int fd_out, fd_in; - int queue; - char mailbuf[9]; - char *mailname = NULL; - FILE *stream; - int send_mail = 0; - struct stat buf; - off_t size; - struct passwd *pentry; - int fflags; - - pid = fork(); - if (pid == -1) - perr("Cannot fork"); - else if (pid > 0) - return; - - /* - * Let's see who we mail to. Hopefully, we can read it from the - * command file; if not, send it to the owner, or, failing that, to - * root. - */ + pid_t res; + res = fork(); + if (res == 0) + kill(getpid(),SIGSTOP); + return res; +} - PRIV_START +#define fork myfork +#endif - stream = fopen(filename, "r"); +static void +run_file(const char *filename, uid_t uid, gid_t gid) +{ +/* Run a file by by spawning off a process which redirects I/O, + * spawns a subshell, then waits for it to complete and sends + * mail to the user. + */ + pid_t pid; + int fd_out, fd_in; + int queue; + char mailbuf[9]; + char *mailname = NULL; + FILE *stream; + int send_mail = 0; + struct stat buf; + off_t size; + struct passwd *pentry; + int fflags; + + + PRIV_START + + if (chmod(filename, S_IRUSR) != 0) + { + perr("Cannot change file permissions"); + } + + PRIV_END + + pid = fork(); + if (pid == -1) + perr("Cannot fork"); + + else if (pid > 0) + return; + + /* Let's see who we mail to. Hopefully, we can read it from + * the command file; if not, send it to the owner, or, failing that, + * to root. + */ + + pentry = getpwuid(uid); + if (pentry == NULL) + { + syslog(LOG_ERR,"Userid %lu not found - aborting job %s", + (unsigned long) uid, filename); + exit(EXIT_FAILURE); + } + PRIV_START - PRIV_END + stream=fopen(filename, "r"); - if (stream == NULL) - perr("Cannot open input file"); + PRIV_END - if ((fd_in = dup(fileno(stream))) < 0) - perr("Error duplicating input file descriptor"); + if (stream == NULL) + perr("Cannot open input file"); - if ((fflags = fcntl(fd_in, F_GETFD)) < 0) - perr("Error in fcntl"); + if ((fd_in = dup(fileno(stream))) <0) + perr("Error duplicating input file descriptor"); - fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC); + if ((fflags = fcntl(fd_in, F_GETFD)) <0) + perr("Error in fcntl"); - if (fscanf(stream, "#! /bin/sh\n# mail %8s %d", mailbuf, &send_mail) == 2) { - mailname = mailbuf; - } else { - pentry = getpwuid(uid); - if (pentry == NULL) - mailname = "root"; - else - mailname = pentry->pw_name; - } - fclose(stream); - if (chdir(_PATH_ATSPOOL) < 0) - perr("Cannot chdir to " _PATH_ATSPOOL); + fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC); - /* - * Create a file to hold the output of the job we are about to - * run. Write the mail header. + if (fscanf(stream, "#! /bin/sh\n# mail %8s %d", mailbuf, &send_mail) == 2) + { + mailname = mailbuf; + pentry = getpwnam(mailname); + if (pentry == NULL || pentry->pw_uid != uid) { + syslog(LOG_ERR,"Userid %lu mismatch name %s - aborting job %s", + (unsigned long) uid, mailname, filename); + exit(EXIT_FAILURE); + } + } + else + { + mailname = pentry->pw_name; + } + fclose(stream); + if (chdir(ATSPOOL_DIR) < 0) + perr("Cannot chdir to " ATSPOOL_DIR); + + /* Create a file to hold the output of the job we are about to run. + * Write the mail header. + */ + if((fd_out=open(filename, + O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0) + perr("Cannot create output file"); + + write_string(fd_out, "Subject: Output from your job "); + write_string(fd_out, filename); + write_string(fd_out, "\n\n"); + fstat(fd_out, &buf); + size = buf.st_size; + + close(STDIN_FILENO); + close(STDOUT_FILENO); + close(STDERR_FILENO); + + pid = fork(); + if (pid < 0) + perr("Error in fork"); + + else if (pid == 0) + { + char *nul = NULL; + char **nenvp = &nul; + + /* Set up things for the child; we want standard input from the input file, + * and standard output and error sent to our output file. */ - if ((fd_out = open(filename, - O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0) - perr("Cannot create output file"); - write_string(fd_out, "Subject: Output from your job "); - write_string(fd_out, filename); - write_string(fd_out, "\n\n"); - fstat(fd_out, &buf); - size = buf.st_size; + if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0) + perr("Error in lseek"); - close(STDIN_FILENO); - close(STDOUT_FILENO); - close(STDERR_FILENO); + if (dup(fd_in) != STDIN_FILENO) + perr("Error in I/O redirection"); - pid = fork(); - if (pid < 0) - perr("Error in fork"); - else if (pid == 0) { - char *nul = NULL; - char **nenvp = &nul; + if (dup(fd_out) != STDOUT_FILENO) + perr("Error in I/O redirection"); - /* - * Set up things for the child; we want standard input from - * the input file, and standard output and error sent to - * our output file. - */ + if (dup(fd_out) != STDERR_FILENO) + perr("Error in I/O redirection"); - if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0) - perr("Error in lseek"); - - if (dup(fd_in) != STDIN_FILENO) - perr("Error in I/O redirection"); - - if (dup(fd_out) != STDOUT_FILENO) - perr("Error in I/O redirection"); - - if (dup(fd_out) != STDERR_FILENO) - perr("Error in I/O redirection"); - - close(fd_in); - close(fd_out); - if (chdir(_PATH_ATJOBS) < 0) - perr("Cannot chdir to " _PATH_ATJOBS); + close(fd_in); + close(fd_out); + if (chdir(ATJOB_DIR) < 0) + perr("Cannot chdir to " ATJOB_DIR); - queue = *filename; + queue = *filename; - PRIV_START + PRIV_START - if (queue > 'b') - nice(queue - 'b'); + nice(tolower(queue) - 'a'); + + chdir(pentry->pw_dir); - if (setgid(gid) < 0) - perr("Cannot change group"); + if (initgroups(pentry->pw_name,pentry->pw_gid)) + perr("Cannot delete saved userids"); - if (setuid(uid) < 0) - perr("Cannot set user id"); + if (setgid(gid) < 0) + perr("Cannot change group"); - chdir("/"); + if (setuid(uid) < 0) + perr("Cannot set user id"); - if (execle("/bin/sh", "sh", (char *) NULL, nenvp) != 0) - perr("Exec failed"); + if(execle("/bin/sh","sh",(char *) NULL, nenvp) != 0) + perr("Exec failed"); - PRIV_END - } - /* We're the parent. Let's wait. */ - close(fd_in); - close(fd_out); - waitpid(pid, (int *) NULL, 0); - - stat(filename, &buf); - if ((buf.st_size != size) || send_mail) { - /* Fork off a child for sending mail */ - pid = fork(); - if (pid < 0) - perr("Fork failed"); - else if (pid == 0) { - if (open(filename, O_RDONLY) != STDIN_FILENO) - perr("Cannot reopen output file"); - - execl(_PATH_SENDMAIL, _PATH_SENDMAIL, mailname, - (char *) NULL); - perr("Exec failed"); - } - waitpid(pid, (int *) NULL, 0); - } - unlink(filename); - exit(EXIT_SUCCESS); + PRIV_END + } + /* We're the parent. Let's wait. + */ + close(fd_in); + close(fd_out); + waitpid(pid, (int *) NULL, 0); + + /* Send mail. Unlink the output file first, so it is deleted after + * the run. + */ + stat(filename, &buf); + if (open(filename, O_RDONLY) != STDIN_FILENO) + perr("Open of jobfile failed"); + + unlink(filename); + if ((buf.st_size != size) || send_mail) + { +#ifdef __FreeBSD__ + execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service", + mailname, (char *) NULL); +#else + execl(MAIL_CMD, MAIL_CMD, mailname, (char *) NULL); +#endif + perr("Exec failed"); + } + exit(EXIT_SUCCESS); } /* Global functions */ int -main(argc, argv) - int argc; - char *argv[]; +main(int argc, char *argv[]) { - /* - * Browse through _PATH_ATJOBS, checking all the jobfiles wether - * they should be executed and or deleted. The queue is coded into - * the first byte of the job filename, the date (in minutes since - * Eon) as a hex number in the following eight bytes, followed by - * a dot and a serial number. A file which has not been executed - * yet is denoted by its execute - bit set. For those files which - * are to be executed, run_file() is called, which forks off a - * child which takes care of I/O redirection, forks off another - * child for execution and yet another one, optionally, for sending - * mail. Files which already have run are removed during the - * next invocation. - */ - DIR *spool; - struct dirent *dirent; - struct stat buf; - int older; - unsigned long ctm; - char queue; - - /* - * We don't need root privileges all the time; running under uid - * and gid daemon is fine. - */ +/* Browse through ATJOB_DIR, checking all the jobfiles wether they should + * be executed and or deleted. The queue is coded into the first byte of + * the job filename, the date (in minutes since Eon) as a hex number in the + * following eight bytes, followed by a dot and a serial number. A file + * which has not been executed yet is denoted by its execute - bit set. + * For those files which are to be executed, run_file() is called, which forks + * off a child which takes care of I/O redirection, forks off another child + * for execution and yet another one, optionally, for sending mail. + * Files which already have run are removed during the next invocation. + */ + DIR *spool; + struct dirent *dirent; + struct stat buf; + unsigned long ctm; + char queue; + time_t now, run_time; + char batch_name[] = "Z2345678901234"; + uid_t batch_uid; + gid_t batch_gid; + int c; + int run_batch; + double load_avg = LOADAVG_MX; + +/* We don't need root privileges all the time; running under uid and gid daemon + * is fine. + */ - RELINQUISH_PRIVS_ROOT(0) /* it's setuid root */ - openlog("atrun", LOG_PID, LOG_CRON); - - namep = argv[0]; - if (chdir(_PATH_ATJOBS) != 0) - perr("Cannot change to " _PATH_ATJOBS); - - /* - * Main loop. Open spool directory for reading and look over all - * the files in there. If the filename indicates that the job - * should be run and the x bit is set, fork off a child which sets - * its user and group id to that of the files and exec a /bin/sh - * which executes the shell script. Unlink older files if they - * should no longer be run. For deletion, their r bit has to be - * turned on. + RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID) + + openlog("atrun", LOG_PID, LOG_CRON); + + opterr = 0; + errno = 0; + while((c=getopt(argc, argv, "dl:"))!= EOF) + { + switch (c) + { + case 'l': + if (sscanf(optarg, "%lf", &load_avg) != 1) + perr("garbled option -l"); + if (load_avg <= 0.) + load_avg = LOADAVG_MX; + break; + + case 'd': + debug ++; + break; + + case '?': + perr("unknown option"); + break; + + default: + perr("idiotic option - aborted"); + break; + } + } + + namep = argv[0]; + if (chdir(ATJOB_DIR) != 0) + perr("Cannot change to " ATJOB_DIR); + + /* Main loop. Open spool directory for reading and look over all the + * files in there. If the filename indicates that the job should be run + * and the x bit is set, fork off a child which sets its user and group + * id to that of the files and exec a /bin/sh which executes the shell + * script. Unlink older files if they should no longer be run. For + * deletion, their r bit has to be turned on. + * + * Also, pick the oldest batch job to run, at most one per invocation of + * atrun. + */ + if ((spool = opendir(".")) == NULL) + perr("Cannot read " ATJOB_DIR); + + now = time(NULL); + run_batch = 0; + batch_uid = (uid_t) -1; + batch_gid = (gid_t) -1; + + while ((dirent = readdir(spool)) != NULL) + { + if (stat(dirent->d_name,&buf) != 0) + perr("Cannot stat in " ATJOB_DIR); + + /* We don't want directories */ - if ((spool = opendir(".")) == NULL) - perr("Cannot read " _PATH_ATJOBS); - - while ((dirent = readdir(spool)) != NULL) { - double la; - - if (stat(dirent->d_name, &buf) != 0) - perr("Cannot stat in " _PATH_ATJOBS); - - /* We don't want directories */ - if (!S_ISREG(buf.st_mode)) - continue; - - if (sscanf(dirent->d_name, "%c%8lx", &queue, &ctm) != 2) - continue; - - if ((queue == 'b') && ((getloadavg(&la, 1) != 1) || - (la > ATRUN_MAXLOAD))) - continue; - - older = (time_t) ctm *60 <= time(NULL); - - /* The file is executable and old enough */ - if (older && (S_IXUSR & buf.st_mode)) { - /* - * Now we know we want to run the file, we can turn - * off the execute bit - */ - - PRIV_START - - if (chmod(dirent->d_name, S_IRUSR) != 0) - perr("Cannot change file permissions"); - - PRIV_END - - run_file(dirent->d_name, buf.st_uid, buf.st_gid); - } - /* Delete older files */ - if (older && !(S_IXUSR & buf.st_mode) && - (S_IRUSR & buf.st_mode)) - unlink(dirent->d_name); + if (!S_ISREG(buf.st_mode)) + continue; + + if (sscanf(dirent->d_name,"%c%8lx",&queue,&ctm) != 2) + continue; + + run_time = (time_t) ctm*60; + + if ((S_IXUSR & buf.st_mode) && (run_time <=now)) + { + if (isupper(queue) && (strcmp(batch_name,dirent->d_name) > 0)) + { + run_batch = 1; + strncpy(batch_name, dirent->d_name, sizeof(batch_name)); + batch_uid = buf.st_uid; + batch_gid = buf.st_gid; + } + + /* The file is executable and old enough + */ + if (islower(queue)) + run_file(dirent->d_name, buf.st_uid, buf.st_gid); } - closelog(); - exit(EXIT_SUCCESS); + /* Delete older files + */ + if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode)) + unlink(dirent->d_name); + } + /* run the single batch file, if any + */ +#ifndef __FreeBSD__ + if (run_batch && (gloadavg() < load_avg)) { +#else + if (run_batch) { + double la; + + if (getloadavg(&la, 1) != 1) + perr("Error in getloadavg"); + if (la < load_avg) +#endif + run_file(batch_name, batch_uid, batch_gid); + } + + closelog(); + exit(EXIT_SUCCESS); } diff --git a/libexec/atrun/atrun.man b/libexec/atrun/atrun.man new file mode 100644 index 0000000..abce667 --- /dev/null +++ b/libexec/atrun/atrun.man @@ -0,0 +1,66 @@ +.\" $Id: atrun.man,v 1.1 1994/05/10 18:23:08 kernel Exp $ +.Dd April 12, 1995 +.Dt ATRUN 8 +.Os "FreeBSD 2.1" +.Sh NAME +.Nm atrun +.Nd run jobs queued for later execution +.Sh SYNOPSIS +.Nm atrun +.Op Fl l Ar load_avg +.Op Fl d +.Sh DESCRIPTION +.Nm Atrun +runs jobs queued by +.Xr at 1 . +Root's +.Xr crontab 5 +file +.Pa /etc/crontab +has to contain the line +.nf +*/5 * * * * root _ATLIB_DIR/atrun +.fi +so +.Xr atrun 8 +gets called every five minutes. +.Pp +At every invocation, every job in lowercase queues whose starting time +has passed is started. +A maximum of one batch jobs (denoted by uppercase queues) are started +each time +.Nm atrun +is invoked. +.Sh OPTIONS +.Bl -tag -width indent +.It Fl l Ar load_avg +Specifies a limiting load factor, over which batch jobs should +not be run, instead of the compiled \- in value of _LOADAVG_MX. +.It Fl d +Debug; print error messages to standard error instead of using +.Xr syslog 3 . +.El +.Sh WARNINGS +For +.Nm atrun +to work, you have to start up a +.Xr cron 8 +daemon. +.Sh FILES +.Bl -tag -width _ATSPOOL_DIR -compact +.It Pa _ATSPOOL_DIR +Directory containing output spool files +.It Pa _ATJOB_DIR +Directory containing job files +.El +.Sh SEE ALSO +.Xr cron 8 , +.Xr crontab 1 , +.Xr crontab 5 , +.Xr at 1 , +.Xr syslog 3 . +.Sh BUGS +The functionality of +.Nm atrun +should be merged into +.Xr cron 8 . -- cgit v1.1