Messages in this thread | | | Date | Thu, 20 Dec 2007 15:17:02 -0500 | From | Phillip Susi <> | Subject | Re: /dev/urandom uses uninit bytes, leaks user data |
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Andrew Lutomirski wrote: > I understand that there's no way that /dev/random can provide good > output if there's insufficient entropy. But it still shouldn't leak > arbitrary bits of user data that were never meant to be put into the > pool at all.
It doesn't leak it though, it consumes it, and it then vanishes into the entropy pool, never to be seen again.
> Step 1: Boot a system without a usable entropy source. > Step 2: add some (predictable) "entropy" from userspace which isn't a > multiple of 4, so up to three extra bytes get added. > Step 3: Read a few bytes of /dev/random and send them over the network.
Only root can do 1 and 2, at which point, it's already game over.
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