1 files changed, 92 insertions, 0 deletions
diff --git a/data/xor.c b/data/xor.c
new file mode 100644
index 0000000..9feead0
--- /dev/null
+++ b/data/xor.c
@@ -0,0 +1,92 @@
+/* Generic xor handler.
+
+   With no args, xors stdin against 0xFF to stdout.  A single argument is a
+   file to read xor-bytes out of.  Any zero in the xor-bytes array is treated
+   as the end; if you need to xor against a string that *includes* zeros,
+   you're on your own.
+
+   The indirect file can be generated easily with data.c.
+
+   Written because there are so many lame schemes for "masking" plaintext
+   passwords and the like floating around, and it's handy to just run an
+   obscure binary-format configuration file through this and look for strings.
+
+   *Hobbit*, 960208 */
+
+#include <stdio.h>
+#include <fcntl.h>
+
+char buf[8192];
+char bytes[256];
+char * py;
+
+/* do the xor, in place.  Uses global ptr "py" to maintain "bytes" state */
+xorb (buf, len)
+  char * buf;
+  int len;
+{
+  register int x;
+  register char * pb;
+
+  pb = buf;
+  x = len;
+  while (x > 0) {
+    *pb = (*pb ^ *py);
+    pb++;
+    py++;
+    if (! *py)
+      py = bytes;
+    x--;
+  }
+} /* xorb */
+
+/* blah */
+main (argc, argv)
+  int argc;
+  char ** argv;
+{
+  register int x = 0;
+  register int y;
+
+/* manually preload; xor-with-0xFF is all too common */
+  memset (bytes, 0, sizeof (bytes));
+  bytes[0] = 0xff;
+
+/* if file named in any arg, reload from that */
+#ifdef O_BINARY				/* DOS shit... */
+  x = setmode (0, O_BINARY);		/* make stdin raw */
+  if (x < 0) {
+    fprintf (stderr, "stdin binary setmode oops: %d\n", x);
+    exit (1);
+  }
+  x = setmode (1, O_BINARY);		/* make stdout raw */
+  if (x < 0) {
+    fprintf (stderr, "stdout binary setmode oops: %d\n", x);
+    exit (1);
+  }
+#endif /* O_BINARY */
+  
+  if (argv[1])
+#ifdef O_BINARY
+    x = open (argv[1], O_RDONLY | O_BINARY);
+#else
+    x = open (argv[1], O_RDONLY);
+#endif
+  if (x > 0) {
+    read (x, bytes, 250);		/* nothin' fancy here */
+    close (x);
+  }
+  py = bytes;
+  x = 1;
+  while (x > 0) {
+    x = read (0, buf, sizeof (buf));
+    if (x <= 0)
+      break;
+    xorb (buf, x);
+    y = write (1, buf, x);
+    if (y <= 0)
+      exit (1);
+  }
+  exit (0);
+}
+