File binddynport-honor-ip_local_reserved_ports.patch of Package libtirpc.27300

Overview Repositories Revisions Requests Users Attributes Meta

File binddynport-honor-ip_local_reserved_ports.patch of Package libtirpc.27300

src/binddynport.c | 107 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 99 insertions(+), 8 deletions(-)

diff --git a/src/binddynport.c b/src/binddynport.c
index 062629a..90e2748 100644
--- a/src/binddynport.c
+++ b/src/binddynport.c
@@ -37,6 +37,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
+#include <syslog.h>
 
 #include <rpc/rpc.h>
 
@@ -56,6 +57,84 @@ enum {
 	NPORTS		= ENDPORT - LOWPORT + 1,
 };
 
+/*
+ * This function decodes information about given port from provided array and
+ * return if port is reserved or not.
+ *
+ * @reserved_ports an array of size at least "NPORTS / (8*sizeof(char)) + 1".
+ * @port port number within range LOWPORT and ENDPORT
+ *
+ * Returns 0 if port is not reserved, non-negative if port is reserved.
+ */
+static int is_reserved(char *reserved_ports, int port) {
+	port -= LOWPORT;
+	if (port < 0 || port >= NPORTS)
+		return 0;
+	return reserved_ports[port/(8*sizeof(char))] & 1<<(port%(8*sizeof(char)));
+}
+
+/*
+ * This function encodes information about given *reserved* port into provided
+ * array. Don't call this function for ports which are not reserved.
+ *
+ * @reserved_ports an array of size at least "NPORTS / (8*sizeof(char)) + 1".
+ * @port port number within range LOWPORT and ENDPORT
+ *
+ */
+static void set_reserved(char *reserved_ports, int port) {
+	port -= LOWPORT;
+	if (port < 0 || port >= NPORTS)
+		return;
+	reserved_ports[port/(8*sizeof(char))] |= 1<<(port%(8*sizeof(char)));
+}
+
+/*
+ * Parse local reserved ports obtained from
+ * /proc/sys/net/ipv4/ip_local_reserved_ports into bit array.
+ *
+ * @reserved_ports a zeroed array of size at least
+ * "NPORTS / (8*sizeof(char)) + 1". Will be used for bit-wise encoding of
+ * reserved ports.
+ *
+ * On each call, reserved ports are read from /proc and bit-wise stored into
+ * provided array
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+
+static int parse_reserved_ports(char *reserved_ports) {
+	int from, to;
+	char delimiter = ',';
+	int res;
+	FILE * file_ptr = fopen("/proc/sys/net/ipv4/ip_local_reserved_ports","r");
+	if (file_ptr == NULL) {
+		(void) syslog(LOG_ERR,
+			"Unable to open open /proc/sys/net/ipv4/ip_local_reserved_ports.");
+		return -1;
+	}
+	do {
+		if ((res = fscanf(file_ptr, "%d", &to)) != 1) {
+			if (res == EOF) break;
+			goto err;
+		}
+		if (delimiter != '-') {
+			from = to;
+		}
+		for (int i = from; i <= to; ++i) {
+			set_reserved(reserved_ports, i);
+		}
+	} while ((res = fscanf(file_ptr, "%c", &delimiter)) == 1);
+	if (res != EOF)
+		goto err;
+	fclose(file_ptr);
+	return 0;
+err:
+	(void) syslog(LOG_ERR,
+		"An error occurred while parsing ip_local_reserved_ports.");
+	fclose(file_ptr);
+	return -1;
+}
+
 /*
  * Bind a socket to a dynamically-assigned IP port.
  *
@@ -81,7 +160,8 @@ int __binddynport(int fd)
 	in_port_t port, *portp;
 	struct sockaddr *sap;
 	socklen_t salen;
-	int i, res;
+	int i, res, array_size;
+	char *reserved_ports;
 
 	if (__rpc_sockisbound(fd))
 		return 0;
@@ -119,21 +199,32 @@ int __binddynport(int fd)
 		gettimeofday(&tv, NULL);
 		seed = tv.tv_usec * getpid();
 	}
+	array_size = NPORTS / (8*sizeof(char)) + 1;
+	reserved_ports = malloc(array_size);
+	if (!reserved_ports) {
+		goto out;
+	}
+	memset(reserved_ports, 0, array_size);
+	parse_reserved_ports(reserved_ports);
+
 	port = (rand_r(&seed) % NPORTS) + LOWPORT;
 	for (i = 0; i < NPORTS; ++i) {
-		*portp = htons(port++);
-		res = bind(fd, sap, salen);
-		if (res >= 0) {
-			res = 0;
-			break;
+		*portp = htons(port);
+		if (!is_reserved(reserved_ports, port++)) {
+			res = bind(fd, sap, salen);
+			if (res >= 0) {
+				res = 0;
+				break;
+			}
+			if (errno != EADDRINUSE)
+				break;
 		}
-		if (errno != EADDRINUSE)
-			break;
 		if (port > ENDPORT)
 			port = LOWPORT;
 	}
 
 out:
+	free(reserved_ports);
 	mutex_unlock(&port_lock);
 	return res;
 }
-- 
2.26.2

Places

File binddynport-honor-ip_local_reserved_ports.patch of Package libtirpc.27300

Places