From: Scott Worley <scottworley@scottworley.com>
Date: Thu, 5 Sep 2013 05:06:29 +0000 (-0700)
Subject: Only print to-the-second resolution by default.
X-Git-Tag: v1.0.0~15
X-Git-Url: http://git.scottworley.com/keystroke-timestamps/commitdiff_plain/9779d071833a13aa6163e294a45a0d14ad2cf8e9?hp=-c

Only print to-the-second resolution by default.

Put microseconds behind a flag.

This makes it harder to do timing analysis on the log file to try to
turn this into a keylogger.

(More precise timing information is still available to an on-line attack
by watching the flush timings or by watching the CPU usage and run state
of the process.)
---

9779d071833a13aa6163e294a45a0d14ad2cf8e9
diff --git a/keystroke-timestamps.c b/keystroke-timestamps.c
index 7c82a65..6e3de63 100644
--- a/keystroke-timestamps.c
+++ b/keystroke-timestamps.c
@@ -2,19 +2,25 @@
 #include <fcntl.h>
 #include <linux/input.h>
 #include <stdio.h>
+#include <string.h>
 #include <sysexits.h>
 #include <unistd.h>
 
-int main ()
+int main (int argc, char **argv)
 {
-  struct input_event i;
+  int print_usec = argc > 1 && strcmp(argv[1], "--usec") == 0;
   int fd = open("/dev/input/by-path/platform-i8042-serio-0-event-kbd", O_RDONLY);
   if (fd < 0) {
     err(EX_NOINPUT, "Could not open keyboard event file");
   }
+  struct input_event i;
   while (read(fd, &i, sizeof(i)) == sizeof(i)) {
     if (i.type == 1 && i.value == 1) {
-      printf("%ld.%ld\n", i.time.tv_sec, i.time.tv_usec);
+      if (print_usec) {
+        printf("%ld.%ld\n", i.time.tv_sec, i.time.tv_usec);
+      } else {
+        printf("%ld\n", i.time.tv_sec);
+      }
       fflush(stdout);
     }
   }