On Thu, Feb 12, 2015 at 2:07 AM, <Valdis.Kletnieks@vt.edu> wrote:
On Thu, 12 Feb 2015 00:31:45 +0530, noyb noybee said:
I was planning that the calling process would call the new system call which would return a pseudo-random key that is used as the pass-phrase.
So what prevents malicious code from doing a fork and then calling the new syscall to get its own pseudo-random key to use as a passphrase? Well, any program which has root credentials is still allowed to call chroot(it needs to get a new passphrase before) but not any program with root credentials can exit it. The passphrase last generated(and still unused) will be used as the passphrase for a chroot system call(both needed to be called by the same processes, ofc). Once a passphrase is used for a chroot system call, it is never returned(pseudo-random) again.