[11659] in Athena Bugs
zhm start-up can bring down machine if /etc/zhm.pid is empty
daemon@ATHENA.MIT.EDU (Jonathan I. Kamens)
Tue Jan 25 11:06:37 1994
Date: Tue, 25 Jan 1994 11:07:45 -0500
From: "Jonathan I. Kamens" <jik@security.ov.com>
To: bugs@MIT.EDU
zhm.c, around line 327 in the zhm sources, reads:
/* kill old hm if it exists */
fp = fopen(PidFile, "r");
if (fp != NULL) {
(void)fscanf(fp, "%d\n", &oldpid);
while (!kill(oldpid, SIGTERM))
sleep(1);
syslog(LOG_INFO, "Killed old image.");
(void) fclose(fp);
}
The problem with this is that /etc/zhm.pid is empty, oldpid will be 0,
which means that the signal will be sent to all of the processes in
the process group. During a reboot, this means that the machine will
be brought into single-user mode instead of finishing its reboot.
Here's a patch:
*** zhm.c 1992/12/17 15:32:49
--- zhm.c 1994/01/18 00:40:31
***************
*** 323,332 ****
/* kill old hm if it exists */
fp = fopen(PidFile, "r");
if (fp != NULL) {
! (void)fscanf(fp, "%d\n", &oldpid);
! while (!kill(oldpid, SIGTERM))
! sleep(1);
! syslog(LOG_INFO, "Killed old image.");
(void) fclose(fp);
}
--- 323,333 ----
/* kill old hm if it exists */
fp = fopen(PidFile, "r");
if (fp != NULL) {
! if (fscanf(fp, "%d\n", &oldpid) > 0) {
! while (!kill(oldpid, SIGTERM))
! sleep(1);
! syslog(LOG_INFO, "Killed old image.");
! }
(void) fclose(fp);
}
Jonathan Kamens | OpenVision Technologies, Inc. | jik@security.ov.com
