core: avoid possible asterisk -r crash from long id

When connecting to the remote console, an id string
is first provided that consts of the hostname, pid,
and version.  This is parsed by the remote instance
using a buffer that may be too short, and can allow
a buffer overrun because it is not terminated. This
patch adds termination and a larger buffer.

Review: https://reviewboard.asterisk.org/r/4182/

AFS-254
........

Merged revisions 429223 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/certified/branches/13.1@433918 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/asterisk.c

@@ -3299,7 +3299,7 @@ static int ast_el_read_history(char *filename)
 
 static void ast_remotecontrol(char *data)
 {
-	char buf[80];
+	char buf[256] = "";
 	int res;
 	char filename[80] = "";
 	char *hostname;
@@ -3316,7 +3316,7 @@ static void ast_remotecontrol(char *data)
 	signal(SIGTERM, __remote_quit_handler);
 	signal(SIGHUP, __remote_quit_handler);
 
-	if (read(ast_consock, buf, sizeof(buf)) < 0) {
+	if (read(ast_consock, buf, sizeof(buf) - 1) < 0) {
 		ast_log(LOG_ERROR, "read() failed: %s\n", strerror(errno));
 		return;
 	}