Cleanup hostname matching in syslogd:

1. Hostnames were not treated case insensitively in all cases.

2. The method for stripping hostnames when reading the syslog.conf
   differed from that when finding the hostname of an incoming request.
   This lead to a broken match check.  In my case, it meant I had to
   have '@scooter.smi.example.com.example.com' to have 'logger.example.com'
   properly save messages from 'scooter.smi.sendmail.com'.

3. Add paranoia to cfline() such that it doesn't try to access memory
   outside of the bounds of the f_host string.

4. While I am here, get rid of an outdated comment, argv[{0,1,2}] are now
   checked for NULL after the strdup() calls.

Reviewed by:	dwmalone
MFC after:	1 week

1 files changed, 24 insertions, 17 deletions

diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index 55a3572..e54d817 100644
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -262,6 +262,7 @@ static int	Debug;		/* debug flag */
 static int	resolve = 1;	/* resolve hostname */
 static char	LocalHostName[MAXHOSTNAMELEN];	/* our hostname */
 static char	*LocalDomain;	/* our local domain name */
+static int	LocalDomainLen;	/* length of LocalDomain */
 static int	*finet;		/* Internet datagram socket */
 static int	fklog = -1;	/* /dev/klog */
 static int	Initialized;	/* set when we have initialized ourselves */
@@ -306,7 +307,7 @@ static void	logerror(const char *);
 static void	logmsg(int, const char *, const char *, int);
 static void	log_deadchild(pid_t, int, const char *);
 static void	markit(void);
-static int	skip_message(const char *, const char *);
+static int	skip_message(const char *, const char *, int);
 static void	printline(const char *, char *);
 static void	printsys(char *);
 static int	p_open(const char *, pid_t *);
@@ -763,7 +764,7 @@ static time_t	now;
  * based on the specification.
  */
 static int
-skip_message(const char *name, const char *spec) {
+skip_message(const char *name, const char *spec, int checkcase) {
 	const char *s;
 	char prev, next;
 	int exclude = 0;
@@ -781,7 +782,10 @@ skip_message(const char *name, const char *spec) {
 	default:
 		break;
 	}
-	s = strstr (spec, name);
+	if (checkcase)
+		s = strstr (spec, name);
+	else
+		s = strcasestr (spec, name);
 
 	if (s != NULL) {
 		prev = (s == spec ? ',' : *(s - 1));
@@ -884,11 +888,11 @@ logmsg(int pri, const char *msg, const char *from, int flags)
 			continue;
 
 		/* skip messages with the incorrect hostname */
-		if (skip_message(from, f->f_host))
+		if (skip_message(from, f->f_host, 0))
 			continue;
 
 		/* skip messages with the incorrect program name */
-		if (skip_message(prog, f->f_program))
+		if (skip_message(prog, f->f_program, 1))
 			continue;
 
 		/* skip message to console if it has already been printed */
@@ -1272,9 +1276,8 @@ reapchild(int signo __unused)
 static const char *
 cvthname(struct sockaddr *f)
 {
-	int error;
+	int error, hl;
 	sigset_t omask, nmask;
-	char *p;
 	static char hname[NI_MAXHOST], ip[NI_MAXHOST];
 
 	error = getnameinfo((struct sockaddr *)f,
@@ -1302,9 +1305,12 @@ cvthname(struct sockaddr *f)
 		dprintf("Host name for your address (%s) unknown\n", ip);
 		return (ip);
 	}
-	/* XXX Not quite correct, but close enough for government work. */
-	if ((p = strchr(hname, '.')) && strcasecmp(p + 1, LocalDomain) == 0)
-		*p = '\0';
+	hl = strlen(hname);
+	if (hl > 0 && hname[hl-1] == '.')
+		hname[--hl] = '\0';
+	if (hl > LocalDomainLen && hname[hl-LocalDomainLen] == '.' &&
+	    strcasecmp(hname + hl - LocalDomainLen + 1, LocalDomain) == 0)
+		hname[hl-LocalDomainLen] = '\0';
 	return (hname);
 }
 
@@ -1403,6 +1409,7 @@ init(int signo)
 	} else {
 		LocalDomain = "";
 	}
+	LocalDomainLen = strlen(LocalDomain);
 
 	/*
 	 *  Close all open log files.
@@ -1614,7 +1621,7 @@ cfline(const char *line, struct filed *f, const char *prog, const char *host)
 	if (host && *host == '*')
 		host = NULL;
 	if (host) {
-		int hl, dl;
+		int hl;
 
 		f->f_host = strdup(host);
 		if (f->f_host == NULL) {
@@ -1622,12 +1629,13 @@ cfline(const char *line, struct filed *f, const char *prog, const char *host)
 			exit(1);
 		}
 		hl = strlen(f->f_host);
-		if (f->f_host[hl-1] == '.')
+		if (hl > 0 && f->f_host[hl-1] == '.')
 			f->f_host[--hl] = '\0';
-		dl = strlen(LocalDomain) + 1;
-		if (hl > dl && f->f_host[hl-dl] == '.' &&
-		    strcasecmp(f->f_host + hl - dl + 1, LocalDomain) == 0)
-			f->f_host[hl-dl] = '\0';
+		if (hl > LocalDomainLen &&
+		    f->f_host[hl-LocalDomainLen] == '.' &&
+		    strcasecmp(f->f_host + hl - LocalDomainLen + 1,
+			LocalDomain) == 0)
+			f->f_host[hl-LocalDomainLen] = '\0';
 	}
 
 	/* save program name if any */
@@ -2277,7 +2285,6 @@ p_open(const char *prog, pid_t *pid)
 		return (-1);
 
 	case 0:
-		/* XXX should check for NULL return */
 		argv[0] = strdup("sh");
 		argv[1] = strdup("-c");
 		argv[2] = strdup(prog);