Reimplement attestation code one more time

Move end-to-end attestation code into its own library: patatt. See
https://git.kernel.org/pub/scm/utils/patatt/patatt.git/about/

It is included into b4 as a submodule, but you will need to init it
first:

git submodule update --init

This change significantly simplifies our attestation code, dropping
thousands of lines of rather hairy code. Notably, patatt-style
attestation is incompatible with previous attestation implementations
done directly in b4, but that's just as well -- we've always marked it
as "experimental" and the lack of adoption was proving that we weren't
on the right path.

Next to come is keyring management and documentation.

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>

1 files changed, 21 insertions, 8 deletions

diff --git a/b4/pr.py b/b4/pr.py
index 5e6c7a1..374d8ed 100644
--- a/b4/pr.py
+++ b/b4/pr.py
@@ -122,11 +122,11 @@ def attest_fetch_head(gitdir, lmsg):
     config = b4.get_main_config()
     attpolicy = config['attestation-policy']
     if config['attestation-checkmarks'] == 'fancy':
-        attpass = b4.PASS_FANCY
-        attfail = b4.FAIL_FANCY
+        attpass = b4.ATT_PASS_FANCY
+        attfail = b4.ATT_FAIL_FANCY
     else:
-        attpass = b4.PASS_SIMPLE
-        attfail = b4.FAIL_SIMPLE
+        attpass = b4.ATT_PASS_SIMPLE
+        attfail = b4.ATT_FAIL_SIMPLE
     # Is FETCH_HEAD a tag or a commit?
     htype = b4.git_get_command_lines(gitdir, ['cat-file', '-t', 'FETCH_HEAD'])
     passing = False
@@ -139,17 +139,30 @@ def attest_fetch_head(gitdir, lmsg):
     elif otype == 'commit':
         ecode, out = b4.git_run_command(gitdir, ['verify-commit', '--raw', 'FETCH_HEAD'], logstderr=True)
 
-    good, valid, trusted, attestor, sigdate, errors = b4.validate_gpg_signature(out, 'pgp')
-
-    if good and valid and trusted:
+    good, valid, trusted, keyid, sigtime = b4.check_gpg_status(out)
+    try:
+        uids = b4.get_gpg_uids(keyid)
+        signer = None
+        for uid in uids:
+            if uid.find(f'<{lmsg.fromemail}') >= 0:
+                signer = uid
+                break
+        if not signer:
+            signer = uids[0]
+
+    except KeyError:
+        signer = f'{lmsg.fromname} <{lmsg.fromemail}'
+
+    if good and valid:
         passing = True
 
     out = out.strip()
+    errors = set()
     if not len(out) and attpolicy != 'check':
         errors.add('Remote %s is not signed!' % otype)
 
     if passing:
-        trailer = attestor.get_trailer(lmsg.fromemail)
+        trailer = 'Signed: %s' % signer
         logger.info('  ---')
         logger.info('  %s %s', attpass, trailer)
         return