Write zeros to remove metadata before running luksFormat. (#469177)

This should be fixed in cryptsetup for RHEL5.4 (#468910).

1 files changed, 14 insertions, 0 deletions

diff --git a/cryptodev.py b/cryptodev.py
index 3dac057ca..cde919a3b 100644
--- a/cryptodev.py
+++ b/cryptodev.py
@@ -163,6 +163,20 @@ class LUKSDevice:
         if not device:
             raise ValueError, "Cannot open mapping without a device."
 
+        # zero out the 1MB at the beginning and end of the device in the
+        # hope that it will wipe any metadata from filesystems that
+        # previously occupied this device
+        log.debug("zeroing out beginning and end of %s..." % device)
+        try:
+            fd = os.open("%s/%s" % (devPrefix, device), os.O_RDWR)
+            buf = '\0' * 1024 * 1024
+            os.write(fd, buf)
+            os.lseek(fd, -1024 * 1024, 2)
+            os.write(fd, buf)
+            os.close(fd)
+        except Exception, e:
+            log.error("error zeroing out %s/%s: %s" % (devPrefix, device, e))
+
         log.info("formatting %s as %s" % (device, self.getScheme()))
         p = os.pipe()
         os.write(p[1], "%s\n" % (self.passphrase,))