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Try to be more careful about using using the file descriptor f_file.

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Syslogd should ensure that f_file is a valid file descriptor when
f_type is FILE, CONSOLE, TTY and for a PIPE where f_pid > 0. If the
descriptor is closed/invalid then the type should be set to UNUSED
or the pid should be set to 0.

To this end:
1) Don't close(f->f_file) if we can't send a message to a remote
   host because the file descriptor used for remote logging is
   stored in finet, not in f->f_file. f->f_file is probably
   uninitialised, so I guess we usually end up closing fd 0.
2) Don't close PIPE file descriptors if they are invalid.
3) If the call to p_open fails, don't set the pid.

The OpenBSD patches in this area set f_file to -1 after the fd is
closed and then avoids calling close if f_file < 0. I haven't done
this, but it might be a good idea too.

Inspired by:	PR 67139/OpenBSD
This commit is contained in:
David Malone 2004-05-30 00:02:19 +00:00
parent 75030d0676
commit 3b7e120185
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=129855
1 changed files with 13 additions and 7 deletions
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20
usr.sbin/syslogd/syslogd.c
View File

@ -150,6 +150,8 @@ int funix[MAXFUNIX];
/*
* This structure represents the files that will have log
* copies printed.
* We require f_file to be valid if f_type is F_FILE, F_CONSOLE, F_TTY
* or if f_type if F_PIPE and f_pid > 0.
*/
struct filed {
@ -1131,7 +1133,6 @@ fprintlog(struct filed *f, int flags, const char *msg)
/* case ECONNREFUSED: */
default:
dprintf("removing entry\n");
(void)close(f->f_file);
f->f_type = F_UNUSED;
break;
}
@ -1390,8 +1391,10 @@ die(int signo)
/* flush any pending output */
if (f->f_prevcount)
fprintlog(f, 0, (char *)NULL);
if (f->f_type == F_PIPE)
if (f->f_type == F_PIPE && f->f_un.f_pipe.f_pid > 0) {
(void)close(f->f_file);
f->f_un.f_pipe.f_pid = 0;
}
}
Initialized = was_initialized;
if (signo) {
@ -1457,10 +1460,11 @@ init(int signo)
(void)close(f->f_file);
break;
case F_PIPE:
(void)close(f->f_file);
if (f->f_un.f_pipe.f_pid > 0)
if (f->f_un.f_pipe.f_pid > 0) {
(void)close(f->f_file);
deadq_enter(f->f_un.f_pipe.f_pid,
f->f_un.f_pipe.f_pname);
}
f->f_un.f_pipe.f_pid = 0;
break;
}
@ -2289,9 +2293,10 @@ validate(struct sockaddr *sa, const char *hname)
* opposed to a FILE *.
*/
static int
p_open(const char *prog, pid_t *pid)
p_open(const char *prog, pid_t *rpid)
{
int pfd[2], nulldesc, i;
pid_t pid;
sigset_t omask, mask;
char *argv[4]; /* sh -c cmd NULL */
char errmsg[200];
@ -2306,7 +2311,7 @@ p_open(const char *prog, pid_t *pid)
sigaddset(&mask, SIGALRM);
sigaddset(&mask, SIGHUP);
sigprocmask(SIG_BLOCK, &mask, &omask);
switch ((*pid = fork())) {
switch ((pid = fork())) {
case -1:
sigprocmask(SIG_SETMASK, &omask, 0);
close(nulldesc);
@ -2364,9 +2369,10 @@ p_open(const char *prog, pid_t *pid)
(void)snprintf(errmsg, sizeof errmsg,
"Warning: cannot change pipe to PID %d to "
"non-blocking behaviour.",
(int)*pid);
(int)pid);
logerror(errmsg);
}
*rpid = pid;
return (pfd[1]);
}