From: Karel Zak <kzak@redhat.com>
Date: Mon, 2 May 2022 13:30:26 +0000 (+0200)
Subject: logger: make sure structured data are escaped
X-Git-Tag: v2.39-rc1~678
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6ab10df254c62e1abf962a8756c0cd4aa333a47f;p=thirdparty%2Futil-linux.git

logger: make sure structured data are escaped

For the option --sd-param all formatting chars (" \ and ]) has to be
escaped by \. This patch also allow escape [ to make it more user
friendly.

For example

$ logger --rfc5424 --sd-id zoo@123 --sd-param 'foo="b\"A\"r"' --no-act --stderr "this is message"
<13>1 2022-05-02T15:35:00.342141+02:00 ws.net.home kzak - - [timeQuality tzKnown="1" isSynced="1" syncAccuracy="45291"][zoo@123 foo="b\"A\"r"] this is message

Reported-by: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index 50ae211056..bec684f15b 100644
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -684,13 +684,37 @@ static char *get_structured_data_string(struct logger_ctl *ctl)
 
 static int valid_structured_data_param(const char *str)
 {
+	char *s;
 	char *eq  = strchr(str, '='),
 	     *qm1 = strchr(str, '"'),
-	     *qm2 = qm1 ? strchr(qm1 + 1, '"') : NULL;
+	     *qm2 = qm1 ? ul_strchr_escaped(qm1 + 1, '"') : NULL;
 
-	if (!eq || !qm1 || !qm2)		/* something is missing */
+	/* something is missing */
+	if (!eq || !qm1 || !qm2)
 		return 0;
 
+	/* ']' need to be escaped */
+	for (s = qm1 + 1; s && *s; ) {
+		char *p = strchr(s, ']');
+		if (!p)
+			break;
+		if (p > qm2 || p == ul_strchr_escaped(s, ']'))
+			return 0;
+		s = p + 1;
+	}
+
+	/* '\' is allowed only before '[]"\' chars */
+	for (s = qm1 + 1; s && *s; ) {
+		char *p = strchr(s, '\\');
+		if (!p)
+			break;
+		if (!strchr("[]\"\\", *(p + 1)))
+			return 0;
+		s = p + 1;
+		if (*s == '\\')
+			s++;
+	}
+
 	/* foo="bar" */
 	return eq > str && eq < qm1 && eq + 1 == qm1 && qm1 < qm2 && *(qm2 + 1) == '\0';
 }