The signature data is in memory to begin with, so there's no need to
write it to disk only to immediately read it back.
Also, because the GPGME multi-keyring workaround is somewhat expensive
to setup and teardown, concatenate all signatures into a single GBytes
so _ostree_gpg_verifier_check_signature() is only called once. We're
currently only looking for one valid signature anyway.
This sets the stage for more advanced signature management.
(Also, talking to GPG over pipes sucks.)
Previously we were spawning gpgv2 with a bunch of --keyring options
for /usr/share/ostree/trusted.gpg.d/ and whatever other keyring files
were explicitly added. GPGME has no public API for multiple keyrings,
so we work around the issue by setting up a temp directory to serve as
a fake "home" directory for the crypto engine and then concatenate all
the keyring files into a single public keyring (pubring.gpg).
Unfortunately at present we do this on every signature verification.
There's a desire to cache this concatenation, but the problem is the
user may be unprivileged. So it seems the cache would have to be per
user under $XDG_CACHE_HOME, which OSTree doesn't otherwise use. I'm
open to suggestions.
We do at least clean up the temp directory when finished, and I have
further API changes planned to OstreeGpgVerifier to help mitigate the
performance impact.
The intent of this code I'm fairly certain was to use *.gpg from the
trusted.gpg.d, directory. But right now, we're only using
"pubring.gpg" from that directory, which is odd.
Let's fix this to use all keys ending in .gpg, which will also
include pubring.gpg.
This uses gpgv for verification against DATADIR/ostree/pubring.gpg by
default. The keyring can be overridden by specifying OSTREE_GPG_HOME.
Add a unit test for commit signing with gpg key and verifying on pull;
to implement this we ship a test GPG key generated with no password
for Ostree Tester <test@test.com>.
Change all of the existing tests to disable GPG verification.
Matthew Barnes
Colin Walters
Jeremy Whiting