Fixes bug 29530, where the LOG_ERR messages were occurring when
we had no configured network, and so we were failing the unit tests
because of the recently-merged #28668.
Bug not in any released Tor.
This test fails in some environments; since the code isn't used in
0.4.0, let's disable it for now.
Band-aid solution for #29534; bug not in any released Tor.
malloc_options needs to be declared extern (and declaring it extern
means we need to initialize it separately)
Fixes bug 29145; bugfix on 0.2.9.3-alpha
Signed-off-by: Kris Katterjohn <katterjohn@gmail.com>
This module is currently implemented to use the same technique as
libottery (later used by the bsds' arc4random replacement), using
AES-CTR-256 as its underlying stream cipher. It's backtracking-
resistant immediately after each call, and prediction-resistant
after a while.
Here's how it works:
We generate psuedorandom bytes using AES-CTR-256. We generate BUFLEN bytes
at a time. When we do this, we keep the first SEED_LEN bytes as the key
and the IV for our next invocation of AES_CTR, and yield the remaining
BUFLEN - SEED_LEN bytes to the user as they invoke the PRNG. As we yield
bytes to the user, we clear them from the buffer.
Every RESEED_AFTER times we refill the buffer, we mix in an additional
SEED_LEN bytes from our strong PRNG into the seed.
If the user ever asks for a huge number of bytes at once, we pull SEED_LEN
bytes from the PRNG and use them with our stream cipher to fill the user's
request.
Using an anonymous mmap() is a good way to get pages that we can set
kernel-level flags on, like minherit() or madvise() or mlock().
We're going to use that so that we can make uninheritable locked
pages to store PRNG data.
