[libnf_ct PATCH v2 8/9] Fix buffer overflow in protocol related snprintf functions

[Daniel Gröber <dxld@xxxxxxxxxxxxx>]

Signed-off-by: Daniel Gröber <dxld@xxxxxxxxxxxxx>
---
 src/conntrack/snprintf_default.c | 14 ++++++--------
 src/conntrack/snprintf_xml.c     | 20 ++++++++++++++++++--
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/conntrack/snprintf_default.c b/src/conntrack/snprintf_default.c
index d00c5cb..d18d2f2 100644
--- a/src/conntrack/snprintf_default.c
+++ b/src/conntrack/snprintf_default.c
@@ -13,20 +13,18 @@ static int __snprintf_l3protocol(char *buf,
 				 unsigned int len,
 				 const struct nf_conntrack *ct)
 {
-	return (snprintf(buf, len, "%-8s %u ", 
-		l3proto2str[ct->head.orig.l3protonum] == NULL ?
-		"unknown" : l3proto2str[ct->head.orig.l3protonum], 
-		 ct->head.orig.l3protonum));
+	uint8_t num = ct->head.orig.l3protonum;
+
+	return snprintf(buf, len, "%-8s %u ", __l3proto2str(num), num);
 }
 
 int __snprintf_protocol(char *buf,
 			unsigned int len,
 			const struct nf_conntrack *ct)
 {
-	return (snprintf(buf, len, "%-8s %u ", 
-		proto2str[ct->head.orig.protonum] == NULL ?
-		"unknown" : proto2str[ct->head.orig.protonum], 
-		 ct->head.orig.protonum));
+	uint8_t num = ct->head.orig.protonum;
+
+	return snprintf(buf, len, "%-8s %u ", __proto2str(num), num);
 }
 
 static int __snprintf_timeout(char *buf,
diff --git a/src/conntrack/snprintf_xml.c b/src/conntrack/snprintf_xml.c
index c3a836a..e557df2 100644
--- a/src/conntrack/snprintf_xml.c
+++ b/src/conntrack/snprintf_xml.c
@@ -55,12 +55,28 @@
 
 const char *__proto2str(uint8_t protonum)
 {
-	return proto2str[protonum] ? proto2str[protonum] : "unknown";
+	const char *str = NULL;
+
+	if (protonum < ARRAY_SIZE(proto2str))
+		str = proto2str[protonum];
+
+	if (str == NULL)
+		str = "unknown";
+
+	return str;
 }
 
 const char *__l3proto2str(uint8_t protonum)
 {
-	return l3proto2str[protonum] ? l3proto2str[protonum] : "unknown";
+	const char *str = NULL;
+
+	if (protonum < ARRAY_SIZE(l3proto2str))
+		str = l3proto2str[protonum];
+
+	if (str == NULL)
+		str = "unknown";
+
+	return str;
 }
 
 static int __snprintf_ipv4_xml(char *buf,
-- 
2.20.1