Fix #897 and shuffle directory around (#1054)

* Fix #897 and shuffle directory around

* Update find-lint

* goimports

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

internal/keydb/cache/keydb.go

@@ -0,0 +1,69 @@
+package cache
+
+import (
+	"context"
+	"errors"
+
+	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/internal/keydb"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// A Database implements gomatrixserverlib.KeyDatabase and is used to store
+// the public keys for other matrix servers.
+type KeyDatabase struct {
+	inner keydb.Database
+	cache caching.ImmutableCache
+}
+
+func NewKeyDatabase(inner keydb.Database, cache caching.ImmutableCache) (*KeyDatabase, error) {
+	if inner == nil {
+		return nil, errors.New("inner database can't be nil")
+	}
+	if cache == nil {
+		return nil, errors.New("cache can't be nil")
+	}
+	return &KeyDatabase{
+		inner: inner,
+		cache: cache,
+	}, nil
+}
+
+// FetcherName implements KeyFetcher
+func (d KeyDatabase) FetcherName() string {
+	return "InMemoryKeyCache"
+}
+
+// FetchKeys implements gomatrixserverlib.KeyDatabase
+func (d *KeyDatabase) FetchKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	results := make(map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult)
+	for req := range requests {
+		if res, cached := d.cache.GetServerKey(req); cached {
+			results[req] = res
+			delete(requests, req)
+		}
+	}
+	fromDB, err := d.inner.FetchKeys(ctx, requests)
+	if err != nil {
+		return results, err
+	}
+	for req, res := range fromDB {
+		results[req] = res
+		d.cache.StoreServerKey(req, res)
+	}
+	return results, nil
+}
+
+// StoreKeys implements gomatrixserverlib.KeyDatabase
+func (d *KeyDatabase) StoreKeys(
+	ctx context.Context,
+	keyMap map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	for req, res := range keyMap {
+		d.cache.StoreServerKey(req, res)
+	}
+	return d.inner.StoreKeys(ctx, keyMap)
+}

internal/keydb/interface.go

@@ -0,0 +1,13 @@
+package keydb
+
+import (
+	"context"
+
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+type Database interface {
+	FetcherName() string
+	FetchKeys(ctx context.Context, requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error)
+	StoreKeys(ctx context.Context, keyMap map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult) error
+}

internal/keydb/keydb.go

@@ -0,0 +1,50 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !wasm
+
+package keydb
+
+import (
+	"net/url"
+
+	"golang.org/x/crypto/ed25519"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/keydb/postgres"
+	"github.com/matrix-org/dendrite/internal/keydb/sqlite3"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// NewDatabase opens a database connection.
+func NewDatabase(
+	dataSourceName string,
+	dbProperties internal.DbProperties,
+	serverName gomatrixserverlib.ServerName,
+	serverKey ed25519.PublicKey,
+	serverKeyID gomatrixserverlib.KeyID,
+) (Database, error) {
+	uri, err := url.Parse(dataSourceName)
+	if err != nil {
+		return postgres.NewDatabase(dataSourceName, dbProperties, serverName, serverKey, serverKeyID)
+	}
+	switch uri.Scheme {
+	case "postgres":
+		return postgres.NewDatabase(dataSourceName, dbProperties, serverName, serverKey, serverKeyID)
+	case "file":
+		return sqlite3.NewDatabase(dataSourceName, serverName, serverKey, serverKeyID)
+	default:
+		return postgres.NewDatabase(dataSourceName, dbProperties, serverName, serverKey, serverKeyID)
+	}
+}

internal/keydb/keydb_wasm.go

@@ -0,0 +1,48 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package keydb
+
+import (
+	"fmt"
+	"net/url"
+
+	"golang.org/x/crypto/ed25519"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/keydb/sqlite3"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// NewDatabase opens a database connection.
+func NewDatabase(
+	dataSourceName string,
+	dbProperties internal.DbProperties, // nolint:unparam
+	serverName gomatrixserverlib.ServerName,
+	serverKey ed25519.PublicKey,
+	serverKeyID gomatrixserverlib.KeyID,
+) (Database, error) {
+	uri, err := url.Parse(dataSourceName)
+	if err != nil {
+		return nil, err
+	}
+	switch uri.Scheme {
+	case "postgres":
+		return nil, fmt.Errorf("Cannot use postgres implementation")
+	case "file":
+		return sqlite3.NewDatabase(dataSourceName, serverName, serverKey, serverKeyID)
+	default:
+		return nil, fmt.Errorf("Cannot use postgres implementation")
+	}
+}

internal/keydb/keyring.go

@@ -0,0 +1,74 @@
+// Copyright 2017 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package keydb
+
+import (
+	"encoding/base64"
+
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/crypto/ed25519"
+)
+
+// CreateKeyRing creates and configures a KeyRing object.
+//
+// It creates the necessary key fetchers and collects them into a KeyRing
+// backed by the given KeyDatabase.
+func CreateKeyRing(client gomatrixserverlib.Client,
+	keyDB gomatrixserverlib.KeyDatabase,
+	cfg config.KeyPerspectives) gomatrixserverlib.KeyRing {
+
+	fetchers := gomatrixserverlib.KeyRing{
+		KeyFetchers: []gomatrixserverlib.KeyFetcher{
+			&gomatrixserverlib.DirectKeyFetcher{
+				Client: client,
+			},
+		},
+		KeyDatabase: keyDB,
+	}
+
+	logrus.Info("Enabled direct key fetcher")
+
+	var b64e = base64.StdEncoding.WithPadding(base64.NoPadding)
+	for _, ps := range cfg {
+		perspective := &gomatrixserverlib.PerspectiveKeyFetcher{
+			PerspectiveServerName: ps.ServerName,
+			PerspectiveServerKeys: map[gomatrixserverlib.KeyID]ed25519.PublicKey{},
+			Client:                client,
+		}
+
+		for _, key := range ps.Keys {
+			rawkey, err := b64e.DecodeString(key.PublicKey)
+			if err != nil {
+				logrus.WithError(err).WithFields(logrus.Fields{
+					"server_name": ps.ServerName,
+					"public_key":  key.PublicKey,
+				}).Warn("Couldn't parse perspective key")
+				continue
+			}
+			perspective.PerspectiveServerKeys[key.KeyID] = rawkey
+		}
+
+		fetchers.KeyFetchers = append(fetchers.KeyFetchers, perspective)
+
+		logrus.WithFields(logrus.Fields{
+			"server_name":     ps.ServerName,
+			"num_public_keys": len(ps.Keys),
+		}).Info("Enabled perspective key fetcher")
+	}
+
+	return fetchers
+}

internal/keydb/postgres/keydb.go

@@ -0,0 +1,115 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package postgres
+
+import (
+	"context"
+	"time"
+
+	"golang.org/x/crypto/ed25519"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// A Database implements gomatrixserverlib.KeyDatabase and is used to store
+// the public keys for other matrix servers.
+type Database struct {
+	statements serverKeyStatements
+}
+
+// NewDatabase prepares a new key database.
+// It creates the necessary tables if they don't already exist.
+// It prepares all the SQL statements that it will use.
+// Returns an error if there was a problem talking to the database.
+func NewDatabase(
+	dataSourceName string,
+	dbProperties internal.DbProperties,
+	serverName gomatrixserverlib.ServerName,
+	serverKey ed25519.PublicKey,
+	serverKeyID gomatrixserverlib.KeyID,
+) (*Database, error) {
+	db, err := sqlutil.Open("postgres", dataSourceName, dbProperties)
+	if err != nil {
+		return nil, err
+	}
+	d := &Database{}
+	err = d.statements.prepare(db)
+	if err != nil {
+		return nil, err
+	}
+	// Store our own keys so that we don't end up making HTTP requests to find our
+	// own keys
+	index := gomatrixserverlib.PublicKeyLookupRequest{
+		ServerName: serverName,
+		KeyID:      serverKeyID,
+	}
+	value := gomatrixserverlib.PublicKeyLookupResult{
+		VerifyKey: gomatrixserverlib.VerifyKey{
+			Key: gomatrixserverlib.Base64String(serverKey),
+		},
+		ValidUntilTS: gomatrixserverlib.AsTimestamp(time.Now().Add(100 * 365 * 24 * time.Hour)),
+		ExpiredTS:    gomatrixserverlib.PublicKeyNotExpired,
+	}
+	err = d.StoreKeys(
+		context.Background(),
+		map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult{
+			index: value,
+		},
+	)
+	if err != nil {
+		return nil, err
+	}
+	return d, nil
+}
+
+// FetcherName implements KeyFetcher
+func (d Database) FetcherName() string {
+	return "PostgresKeyDatabase"
+}
+
+// FetchKeys implements gomatrixserverlib.KeyDatabase
+func (d *Database) FetchKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	return d.statements.bulkSelectServerKeys(ctx, requests)
+}
+
+// StoreKeys implements gomatrixserverlib.KeyDatabase
+func (d *Database) StoreKeys(
+	ctx context.Context,
+	keyMap map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	// TODO: Inserting all the keys within a single transaction may
+	// be more efficient since the transaction overhead can be quite
+	// high for a single insert statement.
+	var lastErr error
+	for request, keys := range keyMap {
+		if err := d.statements.upsertServerKeys(ctx, request, keys); err != nil {
+			// Rather than returning immediately on error we try to insert the
+			// remaining keys.
+			// Since we are inserting the keys outside of a transaction it is
+			// possible for some of the inserts to succeed even though some
+			// of the inserts have failed.
+			// Ensuring that we always insert all the keys we can means that
+			// this behaviour won't depend on the iteration order of the map.
+			lastErr = err
+		}
+	}
+	return lastErr
+}

internal/keydb/postgres/server_key_table.go

@@ -0,0 +1,144 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package postgres
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+
+	"github.com/lib/pq"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const serverKeysSchema = `
+-- A cache of signing keys downloaded from remote servers.
+CREATE TABLE IF NOT EXISTS keydb_server_keys (
+	-- The name of the matrix server the key is for.
+	server_name TEXT NOT NULL,
+	-- The ID of the server key.
+	server_key_id TEXT NOT NULL,
+	-- Combined server name and key ID separated by the ASCII unit separator
+	-- to make it easier to run bulk queries.
+	server_name_and_key_id TEXT NOT NULL,
+	-- When the key is valid until as a millisecond timestamp.
+	-- 0 if this is an expired key (in which case expired_ts will be non-zero)
+	valid_until_ts BIGINT NOT NULL,
+	-- When the key expired as a millisecond timestamp.
+	-- 0 if this is an active key (in which case valid_until_ts will be non-zero)
+	expired_ts BIGINT NOT NULL,
+	-- The base64-encoded public key.
+	server_key TEXT NOT NULL,
+	CONSTRAINT keydb_server_keys_unique UNIQUE (server_name, server_key_id)
+);
+
+CREATE INDEX IF NOT EXISTS keydb_server_name_and_key_id ON keydb_server_keys (server_name_and_key_id);
+`
+
+const bulkSelectServerKeysSQL = "" +
+	"SELECT server_name, server_key_id, valid_until_ts, expired_ts, " +
+	"   server_key FROM keydb_server_keys" +
+	" WHERE server_name_and_key_id = ANY($1)"
+
+const upsertServerKeysSQL = "" +
+	"INSERT INTO keydb_server_keys (server_name, server_key_id," +
+	" server_name_and_key_id, valid_until_ts, expired_ts, server_key)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT ON CONSTRAINT keydb_server_keys_unique" +
+	" DO UPDATE SET valid_until_ts = $4, expired_ts = $5, server_key = $6"
+
+type serverKeyStatements struct {
+	bulkSelectServerKeysStmt *sql.Stmt
+	upsertServerKeysStmt     *sql.Stmt
+}
+
+func (s *serverKeyStatements) prepare(db *sql.DB) (err error) {
+	_, err = db.Exec(serverKeysSchema)
+	if err != nil {
+		return
+	}
+	if s.bulkSelectServerKeysStmt, err = db.Prepare(bulkSelectServerKeysSQL); err != nil {
+		return
+	}
+	if s.upsertServerKeysStmt, err = db.Prepare(upsertServerKeysSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *serverKeyStatements) bulkSelectServerKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	var nameAndKeyIDs []string
+	for request := range requests {
+		nameAndKeyIDs = append(nameAndKeyIDs, nameAndKeyID(request))
+	}
+	stmt := s.bulkSelectServerKeysStmt
+	rows, err := stmt.QueryContext(ctx, pq.StringArray(nameAndKeyIDs))
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectServerKeys: rows.close() failed")
+	results := map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult{}
+	for rows.Next() {
+		var serverName string
+		var keyID string
+		var key string
+		var validUntilTS int64
+		var expiredTS int64
+		if err = rows.Scan(&serverName, &keyID, &validUntilTS, &expiredTS, &key); err != nil {
+			return nil, err
+		}
+		r := gomatrixserverlib.PublicKeyLookupRequest{
+			ServerName: gomatrixserverlib.ServerName(serverName),
+			KeyID:      gomatrixserverlib.KeyID(keyID),
+		}
+		vk := gomatrixserverlib.VerifyKey{}
+		err = vk.Key.Decode(key)
+		if err != nil {
+			return nil, err
+		}
+		results[r] = gomatrixserverlib.PublicKeyLookupResult{
+			VerifyKey:    vk,
+			ValidUntilTS: gomatrixserverlib.Timestamp(validUntilTS),
+			ExpiredTS:    gomatrixserverlib.Timestamp(expiredTS),
+		}
+	}
+	return results, rows.Err()
+}
+
+func (s *serverKeyStatements) upsertServerKeys(
+	ctx context.Context,
+	request gomatrixserverlib.PublicKeyLookupRequest,
+	key gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	_, err := s.upsertServerKeysStmt.ExecContext(
+		ctx,
+		string(request.ServerName),
+		string(request.KeyID),
+		nameAndKeyID(request),
+		key.ValidUntilTS,
+		key.ExpiredTS,
+		key.Key.Encode(),
+	)
+	return err
+}
+
+func nameAndKeyID(request gomatrixserverlib.PublicKeyLookupRequest) string {
+	return string(request.ServerName) + "\x1F" + string(request.KeyID)
+}

internal/keydb/sqlite3/keydb.go

@@ -0,0 +1,116 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sqlite3
+
+import (
+	"context"
+	"time"
+
+	"golang.org/x/crypto/ed25519"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// A Database implements gomatrixserverlib.KeyDatabase and is used to store
+// the public keys for other matrix servers.
+type Database struct {
+	statements serverKeyStatements
+}
+
+// NewDatabase prepares a new key database.
+// It creates the necessary tables if they don't already exist.
+// It prepares all the SQL statements that it will use.
+// Returns an error if there was a problem talking to the database.
+func NewDatabase(
+	dataSourceName string,
+	serverName gomatrixserverlib.ServerName,
+	serverKey ed25519.PublicKey,
+	serverKeyID gomatrixserverlib.KeyID,
+) (*Database, error) {
+	db, err := sqlutil.Open(internal.SQLiteDriverName(), dataSourceName, nil)
+	if err != nil {
+		return nil, err
+	}
+	d := &Database{}
+	err = d.statements.prepare(db)
+	if err != nil {
+		return nil, err
+	}
+	// Store our own keys so that we don't end up making HTTP requests to find our
+	// own keys
+	index := gomatrixserverlib.PublicKeyLookupRequest{
+		ServerName: serverName,
+		KeyID:      serverKeyID,
+	}
+	value := gomatrixserverlib.PublicKeyLookupResult{
+		VerifyKey: gomatrixserverlib.VerifyKey{
+			Key: gomatrixserverlib.Base64String(serverKey),
+		},
+		ValidUntilTS: gomatrixserverlib.AsTimestamp(time.Now().Add(100 * 365 * 24 * time.Hour)),
+		ExpiredTS:    gomatrixserverlib.PublicKeyNotExpired,
+	}
+	err = d.StoreKeys(
+		context.Background(),
+		map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult{
+			index: value,
+		},
+	)
+	if err != nil {
+		return nil, err
+	}
+	return d, nil
+}
+
+// FetcherName implements KeyFetcher
+func (d Database) FetcherName() string {
+	return "SqliteKeyDatabase"
+}
+
+// FetchKeys implements gomatrixserverlib.KeyDatabase
+func (d *Database) FetchKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	return d.statements.bulkSelectServerKeys(ctx, requests)
+}
+
+// StoreKeys implements gomatrixserverlib.KeyDatabase
+func (d *Database) StoreKeys(
+	ctx context.Context,
+	keyMap map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	// TODO: Inserting all the keys within a single transaction may
+	// be more efficient since the transaction overhead can be quite
+	// high for a single insert statement.
+	var lastErr error
+	for request, keys := range keyMap {
+		if err := d.statements.upsertServerKeys(ctx, request, keys); err != nil {
+			// Rather than returning immediately on error we try to insert the
+			// remaining keys.
+			// Since we are inserting the keys outside of a transaction it is
+			// possible for some of the inserts to succeed even though some
+			// of the inserts have failed.
+			// Ensuring that we always insert all the keys we can means that
+			// this behaviour won't depend on the iteration order of the map.
+			lastErr = err
+		}
+	}
+	return lastErr
+}

internal/keydb/sqlite3/server_key_table.go

@@ -0,0 +1,152 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sqlite3
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const serverKeysSchema = `
+-- A cache of signing keys downloaded from remote servers.
+CREATE TABLE IF NOT EXISTS keydb_server_keys (
+	-- The name of the matrix server the key is for.
+	server_name TEXT NOT NULL,
+	-- The ID of the server key.
+	server_key_id TEXT NOT NULL,
+	-- Combined server name and key ID separated by the ASCII unit separator
+	-- to make it easier to run bulk queries.
+	server_name_and_key_id TEXT NOT NULL,
+	-- When the key is valid until as a millisecond timestamp.
+	-- 0 if this is an expired key (in which case expired_ts will be non-zero)
+	valid_until_ts BIGINT NOT NULL,
+	-- When the key expired as a millisecond timestamp.
+	-- 0 if this is an active key (in which case valid_until_ts will be non-zero)
+	expired_ts BIGINT NOT NULL,
+	-- The base64-encoded public key.
+	server_key TEXT NOT NULL,
+	UNIQUE (server_name, server_key_id)
+);
+
+CREATE INDEX IF NOT EXISTS keydb_server_name_and_key_id ON keydb_server_keys (server_name_and_key_id);
+`
+
+const bulkSelectServerKeysSQL = "" +
+	"SELECT server_name, server_key_id, valid_until_ts, expired_ts, " +
+	"   server_key FROM keydb_server_keys" +
+	" WHERE server_name_and_key_id IN ($1)"
+
+const upsertServerKeysSQL = "" +
+	"INSERT INTO keydb_server_keys (server_name, server_key_id," +
+	" server_name_and_key_id, valid_until_ts, expired_ts, server_key)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT (server_name, server_key_id)" +
+	" DO UPDATE SET valid_until_ts = $4, expired_ts = $5, server_key = $6"
+
+type serverKeyStatements struct {
+	db                       *sql.DB
+	bulkSelectServerKeysStmt *sql.Stmt
+	upsertServerKeysStmt     *sql.Stmt
+}
+
+func (s *serverKeyStatements) prepare(db *sql.DB) (err error) {
+	s.db = db
+	_, err = db.Exec(serverKeysSchema)
+	if err != nil {
+		return
+	}
+	if s.bulkSelectServerKeysStmt, err = db.Prepare(bulkSelectServerKeysSQL); err != nil {
+		return
+	}
+	if s.upsertServerKeysStmt, err = db.Prepare(upsertServerKeysSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *serverKeyStatements) bulkSelectServerKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	var nameAndKeyIDs []string
+	for request := range requests {
+		nameAndKeyIDs = append(nameAndKeyIDs, nameAndKeyID(request))
+	}
+
+	query := strings.Replace(bulkSelectServerKeysSQL, "($1)", internal.QueryVariadic(len(nameAndKeyIDs)), 1)
+
+	iKeyIDs := make([]interface{}, len(nameAndKeyIDs))
+	for i, v := range nameAndKeyIDs {
+		iKeyIDs[i] = v
+	}
+
+	rows, err := s.db.QueryContext(ctx, query, iKeyIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectServerKeys: rows.close() failed")
+	results := map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult{}
+	for rows.Next() {
+		var serverName string
+		var keyID string
+		var key string
+		var validUntilTS int64
+		var expiredTS int64
+		if err = rows.Scan(&serverName, &keyID, &validUntilTS, &expiredTS, &key); err != nil {
+			return nil, err
+		}
+		r := gomatrixserverlib.PublicKeyLookupRequest{
+			ServerName: gomatrixserverlib.ServerName(serverName),
+			KeyID:      gomatrixserverlib.KeyID(keyID),
+		}
+		vk := gomatrixserverlib.VerifyKey{}
+		err = vk.Key.Decode(key)
+		if err != nil {
+			return nil, err
+		}
+		results[r] = gomatrixserverlib.PublicKeyLookupResult{
+			VerifyKey:    vk,
+			ValidUntilTS: gomatrixserverlib.Timestamp(validUntilTS),
+			ExpiredTS:    gomatrixserverlib.Timestamp(expiredTS),
+		}
+	}
+	return results, nil
+}
+
+func (s *serverKeyStatements) upsertServerKeys(
+	ctx context.Context,
+	request gomatrixserverlib.PublicKeyLookupRequest,
+	key gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	_, err := s.upsertServerKeysStmt.ExecContext(
+		ctx,
+		string(request.ServerName),
+		string(request.KeyID),
+		nameAndKeyID(request),
+		key.ValidUntilTS,
+		key.ExpiredTS,
+		key.Key.Encode(),
+	)
+	return err
+}
+
+func nameAndKeyID(request gomatrixserverlib.PublicKeyLookupRequest) string {
+	return string(request.ServerName) + "\x1F" + string(request.KeyID)
+}