When ExtraInfoStatistics is 0, stop including bandwidth usage statistics,
GeoIPFile hashes, ServerTransportPlugin lines, and bridge statistics
by country in extra-info documents.
Fixes bug 29018; bugfix on 0.2.4.1-alpha (and earlier versions).
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.
Because the test is adding entries to the "rend_cache" directly, the
rend_cache_increment_allocation() was never called which made the
rend_cache_clean() call trigger that underflow warning:
rend_cache/clean: [forking] Nov 29 09:55:04.024 [warn] rend_cache_decrement_allocation(): Bug: Underflow in rend_cache_decrement_allocation (on Tor 0.4.0.0-alpha-dev 2240fe63feb9a8cf)
The test is still good and valid.
Fixes#28660
Signed-off-by: David Goulet <dgoulet@torproject.org>
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.
