Pointer values

Posted Nov 18, 2010 13:12 UTC (Thu) by epa (subscriber, #39769)
Parent article: Making attacks a little harder

Generate a 64-bit random value at boot time, then XOR each pointer value with it and hash the result with SHA or similar. These pointers can be recorded in the log file safely; so an unprivileged user can see when two pointers are equal but no other information. The root user can ask the kernel for the secret random value and so decode the log file.

Pointer values

Posted Nov 18, 2010 15:50 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link] (2 responses)

And code to decrypt this XOR number will be published in 20 seconds after kernel release.

Pointer values

Posted Nov 18, 2010 18:40 UTC (Thu) by andfarm (guest, #61973) [Link] (1 responses)

Make it a truncated SHA1 hash, then? Same idea.

Pointer values

Posted Nov 18, 2010 19:47 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

Make an IOCTL and stop inventing lame interfaces?

Pointer values

Posted Nov 22, 2010 10:35 UTC (Mon) by epa (subscriber, #39769) [Link]

On second thoughts I realize that even if you knew the secret value you wouldn't be able to reverse the hash function to get the original pointers back. So if you wanted to hide the pointer values you'd need to encrypt them, with a much longer secret key than a mere 64 bits.