sa: document the storage of linting certificates

ca/ca.go

@@ -592,6 +592,11 @@ func (ca *certificateAuthorityImpl) issuePrecertificateInner(ctx context.Context
 		return nil, nil, berrors.InternalServerError("failed to prepare precertificate signing: %s", err)
 	}
 
+	// Note: we write the linting certificate bytes to this table, rather than the precertificate
+	// (which we audit log but do not put in the database). This is to ensure that even if there is
+	// an error immediately after signing the precertificate, we have a record in the DB of what we
+	// intended to sign, and can do revocations based on that. See #6807.
+	// The name of the SA method ("AddPrecertificate") is a historical artifact.
 	_, err = ca.sa.AddPrecertificate(context.Background(), &sapb.AddCertificateRequest{
 		Der:          lintCertBytes,
 		RegID:        issueReq.RegistrationID,

sa/database.go

@@ -283,7 +283,7 @@ func initTables(dbMap *borp.DbMap) {
 	dbMap.AddTableWithName(authzModel{}, "authz2").SetKeys(true, "ID")
 	dbMap.AddTableWithName(orderToAuthzModel{}, "orderToAuthz2").SetKeys(false, "OrderID", "AuthzID")
 	dbMap.AddTableWithName(recordedSerialModel{}, "serials").SetKeys(true, "ID")
-	dbMap.AddTableWithName(precertificateModel{}, "precertificates").SetKeys(true, "ID")
+	dbMap.AddTableWithName(lintingCertModel{}, "precertificates").SetKeys(true, "ID")
 	dbMap.AddTableWithName(keyHashModel{}, "keyHashToSerial").SetKeys(true, "ID")
 	dbMap.AddTableWithName(incidentModel{}, "incidents").SetKeys(true, "ID")
 	dbMap.AddTable(incidentSerialModel{})

sa/db/boulder_sa/20230419000000_CombinedSchema.sql

@@ -173,6 +173,9 @@ CREATE TABLE `orders` (
  PARTITION BY RANGE(id)
 (PARTITION p_start VALUES LESS THAN (MAXVALUE));
 
+-- Note: This table's name is a historical artifact and it is now
+-- used to store linting certificates, not precertificates.
+-- See #6807.
 CREATE TABLE `precertificates` (
   `id` bigint(20) NOT NULL AUTO_INCREMENT,
   `registrationID` bigint(20) NOT NULL,

sa/model.go

@@ -160,7 +160,7 @@ const precertFields = "registrationID, serial, der, issued, expires"
 // SelectPrecertificate selects all fields of one precertificate object
 // identified by serial.
 func SelectPrecertificate(ctx context.Context, s db.OneSelector, serial string) (core.Certificate, error) {
-	var model precertificateModel
+	var model lintingCertModel
 	err := s.SelectOne(
 		ctx,
 		&model,
@@ -384,7 +384,7 @@ type recordedSerialModel struct {
 	Expires        time.Time
 }
 
-type precertificateModel struct {
+type lintingCertModel struct {
 	ID             int64
 	Serial         string
 	RegistrationID int64

sa/sa.go

@@ -206,7 +206,11 @@ func (ssa *SQLStorageAuthority) SetCertificateStatusReady(ctx context.Context, r
 	return &emptypb.Empty{}, nil
 }
 
-// AddPrecertificate writes a record of a precertificate generation to the DB.
+// AddPrecertificate writes a record of a linting certificate to the database.
+//
+// Note: The name "AddPrecertificate" is a historical artifact, and this is now
+// always called with a linting certificate. See #6807.
+//
 // Note: this is not idempotent: it does not protect against inserting the same
 // certificate multiple times. Calling code needs to first insert the cert's
 // serial into the Serials table to ensure uniqueness.
@@ -221,7 +225,7 @@ func (ssa *SQLStorageAuthority) AddPrecertificate(ctx context.Context, req *sapb
 	}
 	serialHex := core.SerialToString(parsed.SerialNumber)
 
-	preCertModel := &precertificateModel{
+	preCertModel := &lintingCertModel{
 		Serial:         serialHex,
 		RegistrationID: req.RegID,
 		DER:            req.Der,