By now, support in the network is widespread and it's time to require
more modern crypto on all Tor instances, whether they're clients or
servers. By doing this early in 0.2.6, we can be sure that at some point
all clients will have reasonable support.
Also, use it to generate test vectors, and add those test vectors
to test_crypto.c
This is based on ed25519.py from the ed25519 webpage; the kludgy hacks
are my own.
This implementation allows somebody to add a blinding factor to a
secret key, and a corresponding blinding factor to the public key.
Robert Ransom came up with this idea, I believe. Nick Hopper proved a
scheme like this secure. The bugs are my own.
For proposal 228, we need to cross-certify our identity with our
curve25519 key, so that we can prove at descriptor-generation time
that we own that key. But how can we sign something with a key that
is only for doing Diffie-Hellman? By converting it to the
corresponding ed25519 point.
See the ALL-CAPS warning in the documentation. According to djb
(IIUC), it is safe to use these keys in the ways that ntor and prop228
are using them, but it might not be safe if we start providing crazy
oracle access.
(Unit tests included. What kind of a monster do you take me for?)
Uses libscrypt when found; otherwise, we don't have scrypt and we
only support openpgp rfc2440 s2k hashing, or pbkdf2.
Includes documentation and unit tests; coverage around 95%. Remaining
uncovered code is sanity-checks that shouldn't be reachable fwict.
These wrappers went into place when the default type for our unit
test functions changed from "void fn(void)" to "void fn(void *arg)".
To generate this patch, I did the same hokey-pokey as before with
replacing all operators used as macro arguments, then I ran a
coccinelle script, then I ran perl script to fix up everything that
used legacy_test_helper, then I manually removed the
legacy_test_helper functions, then I ran a final perl script to put
the operators back how they were.
==============================
#!/usr/bin/perl -w -i -p
s/==,/_X_EQ_,/g;
s/!=,/_X_NE_,/g;
s/<,/_X_LT_,/g;
s/>,/_X_GT_,/g;
s/>=,/_X_GEQ_,/g;
s/<=,/_X_LEQ_,/g;
--------------------
@@
identifier func =~ "test_.*$";
statement S, S2;
@@
static void func (
-void
+void *arg
)
{
... when != S2
+(void) arg;
S
...
}
--------------------
#!/usr/bin/perl -w -i -p
s/, *legacy_test_helper, *([^,]+), *\&legacy_setup, *([^\}]+) *}/, $2, $1, NULL, NULL }/g;
--------------------
#!/usr/bin/perl -w -i -p
s/_X_NEQ_/!=/g;
s/_X_NE_/!=/g;
s/_X_EQ_/==/g;
s/_X_GT_/>/g;
s/_X_LT_/</g;
s/_X_GEQ_/>=/g;
s/_X_LEQ_/<=/g;
--------------------
We previously used FILENAME_PRIVATE identifiers mostly for
identifiers exposed only to the unit tests... but also for
identifiers exposed to the benchmarker, and sometimes for
identifiers exposed to a similar module, and occasionally for no
really good reason at all.
Now, we use FILENAME_PRIVATE identifiers for identifiers shared by
Tor and the unit tests. They should be defined static when we
aren't building the unit test, and globally visible otherwise. (The
STATIC macro will keep us honest here.)
For identifiers used only by the unit tests and never by Tor at all,
on the other hand, we wrap them in #ifdef TOR_UNIT_TESTS.
This is not the motivating use case for the split test/non-test
build system; it's just a test example to see how it works, and to
take a chance to clean up the code a little.
Right now, all our curve25519 backends ignore the high bit of the
public key. But possibly, others could treat the high bit of the
public key as encoding out-of-bounds values, or as something to be
preserved. This could be used to distinguish clients with different
backends, at the cost of killing a circuit.
As a workaround, let's just clear the high bit of each public key
indiscriminately before we use it. Fix for bug 8121, reported by
rransom. Bugfix on 0.2.4.8-alpha.
