From: Harlan Stenn <stenn@ntp.org>
Date: Sun, 7 May 2023 08:46:52 +0000 (-0500)
Subject: Make sure the value returned by refid_str() prints cleanly
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a1b95067e6ca3ed35700cf7371fa41ecad4b87ed;p=thirdparty%2Fntp.git

Make sure the value returned by refid_str() prints cleanly

bk: 6457657cbmOY_RIfIqHA4VWtmCb0iw
---

diff --git a/ChangeLog b/ChangeLog
index 667c836ec..d58088e17 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -89,6 +89,7 @@
 * Only define tv_fmt_libbuf() if we will use it. <stenn@ntp.org>
 * Use recv_buffer instead of the longer recv_space.X_recv_buffer. hart/stenn
 * Disable "embedded NUL in string" warnings in libopts, when we can. <stenn@>
+* Make sure the value returned by refid_str() prints cleanly. <stenn@ntp.org>
 * If DEBUG is enabled, the startup banner now says that debug assertions
   are in force and that ntpd will abort if any are violated. <stenn@ntp.org>
 * syslog valid incoming KoDs.  <stenn@ntp.org>
diff --git a/libntp/numtoa.c b/libntp/numtoa.c
index 5efbe942e..51645de01 100644
--- a/libntp/numtoa.c
+++ b/libntp/numtoa.c
@@ -9,6 +9,7 @@
 #endif
 
 #include <stdio.h>
+#include <ctype.h>
 
 #include "ntp_fp.h"
 #include "lib_strbuf.h"
@@ -42,18 +43,33 @@ refid_str(
 {
 	char *	text;
 	size_t	tlen;
+	char *  cp;
 
 	if (stratum > 1)
 		return numtoa(refid);
 
 	LIB_GETBUF(text);
 	text[0] = '.';
+	/* What if any non-NUL char is not printable? */
 	memcpy(&text[1], &refid, sizeof(refid));
 	text[1 + sizeof(refid)] = '\0';
 	tlen = strlen(text);
 	text[tlen] = '.';
 	text[tlen + 1] = '\0';
 
+	/*
+	 * Now make sure the contents are 'graphic'.
+	 *
+	 * This refid is expected to be up to 4 ascii graphics.
+	 * If any character is not a graphic, replace it with a space.
+	 * This will at least alert the viewer of a problem.
+	 */
+	for (cp = text + 1; *cp; ++cp) {
+		if (!isgraph((int)*cp)) {
+			*cp = ' ';
+		}
+	}
+
 	return text;
 }