From b63280f52f997466f0a8bb70f89a3b705b2eb015 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Fri, 6 Oct 2017 21:39:24 +0200
Subject: [PATCH] Use stack-allocated strings for temporary filenames.

---
 src/conf.c  |  7 +++----
 src/tincd.c | 14 ++++++--------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/src/conf.c b/src/conf.c
index 997a05e8..2e13e456 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -487,6 +487,7 @@ FILE *ask_and_open(const char *filename, const char *what) {
 	FILE *r;
 	char *directory;
 	char line[PATH_MAX];
+	char abspath[PATH_MAX];
 	const char *fn;
 
 	/* Check stdin and stdout */
@@ -520,12 +521,10 @@ FILE *ask_and_open(const char *filename, const char *what) {
 	if(fn[0] != '/') {
 #endif
 		/* The directory is a relative path or a filename. */
-		char *p;
-
 		directory = get_current_dir_name();
-		xasprintf(&p, "%s/%s", directory, fn);
+		snprintf(abspath, sizeof abspath, "%s/%s", directory, fn);
 		free(directory);
-		fn = p;
+		fn = abspath;
 	}
 
 	umask(0077);				/* Disallow everything for group and other */
diff --git a/src/tincd.c b/src/tincd.c
index 22fb726a..84ce0d45 100644
--- a/src/tincd.c
+++ b/src/tincd.c
@@ -390,7 +390,7 @@ static bool keygen(int bits) {
 	BIGNUM *e = NULL;
 	RSA *rsa_key;
 	FILE *f;
-	char *pubname, *privname;
+	char filename[PATH_MAX];
 	BN_GENCB *cb;
 	int result;
 
@@ -417,9 +417,8 @@ static bool keygen(int bits) {
 	} else
 		fprintf(stderr, "Done.\n");
 
-	xasprintf(&privname, "%s/rsa_key.priv", confbase);
-	f = ask_and_open(privname, "private RSA key");
-	free(privname);
+	snprintf(filename, sizeof filename, "%s/rsa_key.priv", confbase);
+	f = ask_and_open(filename, "private RSA key");
 
 	if(!f)
 		return false;
@@ -436,14 +435,13 @@ static bool keygen(int bits) {
 	char *name = get_name();
 
 	if(name) {
-		xasprintf(&pubname, "%s/hosts/%s", confbase, name);
+		snprintf(filename, sizeof filename, "%s/hosts/%s", confbase, name);
 		free(name);
 	} else {
-		xasprintf(&pubname, "%s/rsa_key.pub", confbase);
+		snprintf(filename, sizeof filename, "%s/rsa_key.pub", confbase);
 	}
 
-	f = ask_and_open(pubname, "public RSA key");
-	free(pubname);
+	f = ask_and_open(filename, "public RSA key");
 
 	if(!f)
 		return false;
-- 
2.20.1