nathelper: Fix rare message corruption due to bitwise opts on strings

Credits to Damien Sandras for the report and initial PR!

Closes #2695

(cherry picked from commit ecbd985)
(cherry picked from commit 237997b)

modules/nathelper/sip_pinger.h

@@ -342,7 +342,7 @@ build_sipping(udomain_t *d, str *curi, struct socket_info* s,str *path,
 {
 #define s_len(_s) (sizeof(_s)-1)
 	static char buf[MAX_SIPPING_SIZE];
-	char *p, proto_str[PROTO_NAME_MAX_SIZE];
+	char *p, proto_str[PROTO_NAME_MAX_SIZE+1];
 	str address, port;
 	str st;
 	int len;
@@ -361,7 +361,7 @@ build_sipping(udomain_t *d, str *curi, struct socket_info* s,str *path,
 	sbranch.s = branch;
 	sbranch.len = strlen(branch);
 
-	p = proto2str(s->proto, proto_str);
+	p = proto2upper(s->proto, proto_str);
 	*(p++) = ' ';
 	st.s = proto_str;
 	st.len = p - proto_str;
@@ -379,9 +379,6 @@ build_sipping(udomain_t *d, str *curi, struct socket_info* s,str *path,
 	else
 		port = s->port_no_str;
 
-	/* quick proto uppercase */
-	*((int *)st.s) &= ~((1 << 21) | (1 << 13) | (1 << 5));
-
 	if ( sipping_method.len + 1 + curi->len + s_len(" SIP/2.0"CRLF) +
 		s_len("Via: SIP/2.0/") + st.len + address.len +
 		1 + port.len + strlen(branch) +

socket_info.h

@@ -400,11 +400,46 @@ static inline char* proto2str(int proto, char *p)
 	return p;
 }
 
+static inline char* proto2upper(int proto, char *p)
+{
+	switch (proto) {
+	case PROTO_UDP:
+		memcpy(p, STR_L("UDP"));
+		break;
+	case PROTO_TCP:
+		memcpy(p, STR_L("TCP"));
+		break;
+	case PROTO_TLS:
+		memcpy(p, STR_L("TLS"));
+		break;
+	case PROTO_SCTP:
+		memcpy(p, STR_L("SCTP"));
+		break;
+	case PROTO_WS:
+		memcpy(p, STR_L("WS"));
+		break;
+	case PROTO_WSS:
+		memcpy(p, STR_L("WSS"));
+		break;
+	case PROTO_BIN:
+		memcpy(p, STR_L("BIN"));
+		break;
+	case PROTO_HEP_UDP:
+		memcpy(p, STR_L("HEP_UDP"));
+		break;
+	case PROTO_HEP_TCP:
+		memcpy(p, STR_L("HEP_TCP"));
+		break;
+	default:
+		LM_CRIT("unsupported proto %d\n", proto);
+	}
+
+	return p;
+}
 
 static inline char *proto2a(int proto)
 {
-	static char b[8]; /* IMPORTANT - keep this max aligned with the proto2str
-	                   * with an extra +1 for NULL terminator */
+	static char b[PROTO_NAME_MAX_SIZE+1];
 	char *p;
 
 	/* print the proto name */