base64_decode() was applying an overly conservative check on the
output buffer length that could incorrectly produce an error if the
input encoding contained padding or newlines. Fix this by checking
the output buffer length against the actual decoded length produced
during decoding.
When we "fixed" #18280 in 4e4a7d2b0c
in 0291 it appears that we introduced a bug: The base32_encode
function can read off the end of the input buffer, if the input
buffer size modulo 5 is not equal to 0 or 3.
This is not completely horrible, for two reasons:
* The extra bits that are read are never actually used: so this
is only a crash when asan is enabled, in the worst case. Not a
data leak.
* The input sizes passed to base32_encode are only ever multiples
of 5. They are all either DIGEST_LEN (20), REND_SERVICE_ID_LEN
(10), sizeof(rand_bytes) in addressmap.c (10), or an input in
crypto.c that is forced to a multiple of 5.
So this bug can't actually trigger in today's Tor.
Closes bug 21894; bugfix on 0.2.9.1-alpha.
It looks like 32_encoded_size/64_encode_size APIs are inconsistent
not only in the number of "d"s they have, but also in whether they
count the terminating NUL. Taylor noted this in 86477f4e3f,
but I think we should note the inconsistently more loudly in order
to avoid trouble.
(I ran into trouble with this when writing 30b13fd82e243713c6a0d.)
Note down in the routerstatus_t of a node if the router supports the HSIntro=4
version for the ed25519 authentication key and HSDir=2 version for the v3
descriptor supports.
Signed-off-by: David Goulet <dgoulet@torproject.org>
In order to avoid src/or/hs_service.o to contain no symbols and thus making
clang throw a warning, the functions are now exposed not just to unit tests.
Signed-off-by: David Goulet <dgoulet@torproject.org>
Check that route_len_for_purpose() (helper for new_route_len())
correctly fails a non-fatal bug assertion if it encounters an
unhandled circuit purpose when it is called with exit node info.
Add a new helper function route_len_for_purpose(), which explicitly
lists all of the known circuit purposes for a circuit with a chosen
exit node (unlike previously, where the default route length for a
chosen exit was DEFAULT_ROUTE_LEN + 1 except for two purposes). Add a
non-fatal assertion for unhandled purposes that conservatively returns
DEFAULT_ROUTE_LEN + 1.
Add copious comments documenting which circuits need an extra hop and
why.
Thanks to nickm and dgoulet for providing background information.
