g10: Cache the effective policy. Recompute it when required.

* g10/tofu.c (initdb): Add column effective_policy to the bindings
table.
(record_binding): New parameters effective_policy and set_conflict.
Save the effective policy.  If SET_CONFLICT is set, then set conflict
according to CONFLICT.  Otherwise, preserve the current value of
conflict.  Update callers.
(get_trust): Don't compute the effective policy here...
(get_policy): ... do it here, if it was not cached.  Take new
parameters, PK, the public key, and NOW, the time that the operation
started.  Update callers.
(show_statistics): New parameter PK.  Pass it to get_policy.  Update
callers.
(tofu_notice_key_changed): New function.
* g10/gpgv.c (tofu_notice_key_changed): New stub.
* g10/import.c (import_revoke_cert): Take additional argument CTRL.
Pass it to keydb_update_keyblock.
* g10/keydb.c (keydb_update_keyblock): Take additional argument CTRL.
Update callers.
[USE_TOFU]: Call tofu_notice_key_changed.
* g10/test-stubs.c (tofu_notice_key_changed): New stub.
* tests/openpgp/tofu.scm: Assume that manually setting a binding's
policy to auto does not cause the tofu engine to forget about any
conflict.

--
Signed-off-by: Neal H. Walfield <neal@g10code.com>

We now store the computed policy in the tofu DB (in the
effective_policy column of the bindings table) to avoid computing it
every time, which is expensive.  Further, policy is never overridden
in case of a conflict.  Instead, we detect a conflict if CONFLICT is
not empty.

This change is backwards compatible to existing DBs.  The only minor
incompatibility is that unresolved conflicts won't be automatically
resolved in case we import a direct signature, or cross signatures.

1 files changed, 5 insertions, 0 deletions

diff --git a/g10/tofu.h b/g10/tofu.h
index f114443bc..3ee2f41b4 100644
--- a/g10/tofu.h
+++ b/g10/tofu.h
@@ -139,4 +139,9 @@ void tofu_end_batch_update (ctrl_t ctrl);
 /* Release all of the resources associated with a DB meta-handle.  */
 void tofu_closedbs (ctrl_t ctrl);
 
+/* Whenever a key is modified (e.g., a user id is added or revoked, a
+ * new signature, etc.), this function should be called to cause TOFU
+ * to update its world view.  */
+gpg_error_t tofu_notice_key_changed (ctrl_t ctrl, kbnode_t kb);
+
 #endif /*G10_TOFU_H*/