signing: add a process and retry loop for database signatures

In reality, there is no retrying that happens as of now because we don't
have any import or changing of the keyring going on, but the code is set
up so we can drop this in our new _alpm_process_siglist() function. Wire
up the basics to the sync database validation code, so we see something
like the following:

    $ pacman -Ss unknowntrust
    error: core: signature from "Dan McGee <dpmcgee@gmail.com>" is unknown trust
    error: core: signature from "Dan McGee <dpmcgee@gmail.com>" is unknown trust
    error: database 'core' is not valid (invalid or corrupted database (PGP signature))

    $ pacman -Ss missingsig
    error: core: missing required signature
    error: core: missing required signature
    error: database 'core' is not valid (invalid or corrupted database (PGP signature))

Yes, there is some double output, but this should be fixable in the
future.

Signed-off-by: Dan McGee <dan@archlinux.org>

3 files changed, 81 insertions, 6 deletions

diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
index ef0f1ef4..5477eff4 100644
--- a/lib/libalpm/be_sync.c
+++ b/lib/libalpm/be_sync.c
@@ -70,7 +70,6 @@ static int sync_db_validate(alpm_db_t *db)
 {
 	alpm_siglevel_t level;
 	const char *dbpath;
-	alpm_siglist_t *siglist;
 
 	if(db->status & DB_STATUS_VALID || db->status & DB_STATUS_MISSING) {
 		return 0;
@@ -101,16 +100,26 @@ static int sync_db_validate(alpm_db_t *db)
 	level = alpm_db_get_siglevel(db);
 
 	if(level & ALPM_SIG_DATABASE) {
-		if(_alpm_check_pgp_helper(db->handle, dbpath, NULL,
+		int retry, ret;
+		do {
+			retry = 0;
+			alpm_siglist_t *siglist;
+			ret = _alpm_check_pgp_helper(db->handle, dbpath, NULL,
 					level & ALPM_SIG_DATABASE_OPTIONAL, level & ALPM_SIG_DATABASE_MARGINAL_OK,
-					level & ALPM_SIG_DATABASE_UNKNOWN_OK, &siglist)) {
-			db->handle->pm_errno = ALPM_ERR_DB_INVALID_SIG;
+					level & ALPM_SIG_DATABASE_UNKNOWN_OK, &siglist);
+			if(ret) {
+				retry = _alpm_process_siglist(db->handle, db->treename, siglist,
+						level & ALPM_SIG_DATABASE_OPTIONAL, level & ALPM_SIG_DATABASE_MARGINAL_OK,
+						level & ALPM_SIG_DATABASE_UNKNOWN_OK);
+			}
 			alpm_siglist_cleanup(siglist);
 			free(siglist);
+		} while(retry);
+
+		if(ret) {
+			db->handle->pm_errno = ALPM_ERR_DB_INVALID_SIG;
 			return 1;
 		}
-		alpm_siglist_cleanup(siglist);
-		free(siglist);
 	}
 
 valid:
diff --git a/lib/libalpm/signing.c b/lib/libalpm/signing.c
index 7e05a237..e1b6452c 100644
--- a/lib/libalpm/signing.c
+++ b/lib/libalpm/signing.c
@@ -507,6 +507,69 @@ int _alpm_check_pgp_helper(alpm_handle_t *handle, const char *path,
 	return ret;
 }
 
+int _alpm_process_siglist(alpm_handle_t *handle, const char *identifier,
+		alpm_siglist_t *siglist, int optional, int marginal, int unknown)
+{
+	size_t i;
+	int retry = 0;
+
+	if(!optional && siglist->count == 0) {
+		_alpm_log(handle, ALPM_LOG_ERROR,
+				_("%s: missing required signature\n"), identifier);
+	}
+
+	for(i = 0; i < siglist->count; i++) {
+		alpm_sigresult_t *result = siglist->results + i;
+		const char *name = result->key.uid ? result->key.uid : result->key.fingerprint;
+		switch(result->status) {
+			case ALPM_SIGSTATUS_VALID:
+			case ALPM_SIGSTATUS_KEY_EXPIRED:
+				switch(result->validity) {
+					case ALPM_SIGVALIDITY_FULL:
+						break;
+					case ALPM_SIGVALIDITY_MARGINAL:
+						if(!marginal) {
+							_alpm_log(handle, ALPM_LOG_ERROR,
+									_("%s: signature from \"%s\" is marginal trust\n"),
+									identifier, name);
+						}
+						break;
+					case ALPM_SIGVALIDITY_UNKNOWN:
+						if(!unknown) {
+							_alpm_log(handle, ALPM_LOG_ERROR,
+									_("%s: signature from \"%s\" is unknown trust\n"),
+									identifier, name);
+						}
+						break;
+					case ALPM_SIGVALIDITY_NEVER:
+						_alpm_log(handle, ALPM_LOG_ERROR,
+								_("%s: signature from \"%s\" should never be trusted\n"),
+								identifier, name);
+						break;
+				}
+				break;
+			case ALPM_SIGSTATUS_KEY_UNKNOWN:
+				/* TODO import key here */
+				_alpm_log(handle, ALPM_LOG_ERROR,
+						_("%s: key \"%s\" is unknown\n"),
+						identifier, name);
+				break;
+			case ALPM_SIGSTATUS_SIG_EXPIRED:
+				_alpm_log(handle, ALPM_LOG_ERROR,
+						_("%s: signature from \"%s\" is expired\n"),
+						identifier, name);
+				break;
+			case ALPM_SIGSTATUS_INVALID:
+				_alpm_log(handle, ALPM_LOG_ERROR,
+						_("%s: signature from \"%s\" is invalid\n"),
+						identifier, name);
+				break;
+		}
+	}
+
+	return retry;
+}
+
 /**
  * Check the PGP signature for the given package file.
  * @param pkg the package to check
diff --git a/lib/libalpm/signing.h b/lib/libalpm/signing.h
index ee4a94a0..315d6059 100644
--- a/lib/libalpm/signing.h
+++ b/lib/libalpm/signing.h
@@ -24,9 +24,12 @@
 char *_alpm_sigpath(alpm_handle_t *handle, const char *path);
 int _alpm_gpgme_checksig(alpm_handle_t *handle, const char *path,
 		const char *base64_sig, alpm_siglist_t *result);
+
 int _alpm_check_pgp_helper(alpm_handle_t *handle, const char *path,
 		const char *base64_sig, int optional, int marginal, int unknown,
 		alpm_siglist_t **sigdata);
+int _alpm_process_siglist(alpm_handle_t *handle, const char *identifier,
+		alpm_siglist_t *siglist, int optional, int marginal, int unknown);
 
 #endif /* _ALPM_SIGNING_H */