Implement monorepo layout
Implemented the nexantic monorepo.
Smalltown code was moved to `core`. From now on all code will live in top level directories named after the projects with the exception for general purpose libraries which should go to `<lang>libs`.
General build and utility folders are underscore prefixed.
The repo name will from now on be rNXT (nexantic). I think this change makes sense since components in this repo will not all be part of Smalltown, the Smalltown brand has been claimed by Signon GmbH so we need to change it anyway and the longer we wait the harder it will be to change/move it.
Test Plan: Launched Smalltown using `./scripts/bin/bazel run //core/scripts:launch`
X-Origin-Diff: phab/D210
GitOrigin-RevId: fa5a7f08143d2ead2cb7206b4c63ab641794162c
diff --git a/core/internal/storage/blockdev.go b/core/internal/storage/blockdev.go
new file mode 100644
index 0000000..8bdad12
--- /dev/null
+++ b/core/internal/storage/blockdev.go
@@ -0,0 +1,148 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 storage
+
+import (
+ "encoding/binary"
+ "encoding/hex"
+ "fmt"
+ "git.monogon.dev/source/nexantic.git/core/pkg/devicemapper"
+ "os"
+ "syscall"
+
+ "golang.org/x/sys/unix"
+)
+
+func readDataSectors(path string) (uint64, error) {
+ integrityPartition, err := os.Open(path)
+ if err != nil {
+ return 0, err
+ }
+ defer integrityPartition.Close()
+ // Based on structure defined in
+ // https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/md/dm-integrity.c#n59
+ if _, err := integrityPartition.Seek(16, 0); err != nil {
+ return 0, err
+ }
+ var providedDataSectors uint64
+ if err := binary.Read(integrityPartition, binary.LittleEndian, &providedDataSectors); err != nil {
+ return 0, err
+ }
+ return providedDataSectors, nil
+}
+
+// MapEncryptedBlockDevice maps an encrypted device (node) at baseName to a
+// decrypted device at /dev/$name using the given encryptionKey
+func MapEncryptedBlockDevice(name string, baseName string, encryptionKey []byte) error {
+ integritySectors, err := readDataSectors(baseName)
+ if err != nil {
+ return fmt.Errorf("failed to read the number of usable sectors on the integrity device: %w", err)
+ }
+
+ integrityDevName := fmt.Sprintf("/dev/%v-integrity", name)
+ integrityDMName := fmt.Sprintf("%v-integrity", name)
+ integrityDev, err := devicemapper.CreateActiveDevice(integrityDMName, []devicemapper.Target{
+ devicemapper.Target{
+ Length: integritySectors,
+ Type: "integrity",
+ Parameters: fmt.Sprintf("%v 0 28 J 1 journal_sectors:1024", baseName),
+ },
+ })
+ if err != nil {
+ return fmt.Errorf("failed to create Integrity device: %w", err)
+ }
+ if err := unix.Mknod(integrityDevName, 0600|unix.S_IFBLK, int(integrityDev)); err != nil {
+ unix.Unlink(integrityDevName)
+ devicemapper.RemoveDevice(integrityDMName)
+ return fmt.Errorf("failed to create integrity device node: %w", err)
+ }
+
+ cryptDevName := fmt.Sprintf("/dev/%v", name)
+ cryptDev, err := devicemapper.CreateActiveDevice(name, []devicemapper.Target{
+ devicemapper.Target{
+ Length: integritySectors,
+ Type: "crypt",
+ Parameters: fmt.Sprintf("capi:gcm(aes)-random %v 0 %v 0 1 integrity:28:aead", hex.EncodeToString(encryptionKey), integrityDevName),
+ },
+ })
+ if err != nil {
+ unix.Unlink(integrityDevName)
+ devicemapper.RemoveDevice(integrityDMName)
+ return fmt.Errorf("failed to create crypt device: %w", err)
+ }
+ if err := unix.Mknod(cryptDevName, 0600|unix.S_IFBLK, int(cryptDev)); err != nil {
+ unix.Unlink(cryptDevName)
+ devicemapper.RemoveDevice(name)
+
+ unix.Unlink(integrityDevName)
+ devicemapper.RemoveDevice(integrityDMName)
+ return fmt.Errorf("failed to create crypt device node: %w", err)
+ }
+ return nil
+}
+
+// InitializeEncryptedBlockDevice initializes a new encrypted block device. This can take a long
+// time since all bytes on the mapped block device need to be zeroed.
+func InitializeEncryptedBlockDevice(name, baseName string, encryptionKey []byte) error {
+ integrityPartition, err := os.OpenFile(baseName, os.O_WRONLY, 0)
+ if err != nil {
+ return err
+ }
+ defer integrityPartition.Close()
+ zeroed512BBuf := make([]byte, 4096)
+ if _, err := integrityPartition.Write(zeroed512BBuf); err != nil {
+ return fmt.Errorf("failed to wipe header: %w", err)
+ }
+ integrityPartition.Close()
+
+ integrityDMName := fmt.Sprintf("%v-integrity", name)
+ _, err = devicemapper.CreateActiveDevice(integrityDMName, []devicemapper.Target{
+ devicemapper.Target{
+ Length: 1,
+ Type: "integrity",
+ Parameters: fmt.Sprintf("%v 0 28 J 1 journal_sectors:1024", baseName),
+ },
+ })
+ if err != nil {
+ return fmt.Errorf("failed to create discovery integrity device: %w", err)
+ }
+ if err := devicemapper.RemoveDevice(integrityDMName); err != nil {
+ return fmt.Errorf("failed to remove discovery integrity device: %w", err)
+ }
+
+ if err := MapEncryptedBlockDevice(name, baseName, encryptionKey); err != nil {
+ return err
+ }
+
+ blkdev, err := os.OpenFile(fmt.Sprintf("/dev/%v", name), unix.O_DIRECT|os.O_WRONLY, 0000)
+ if err != nil {
+ return fmt.Errorf("failed to open new encrypted device for zeroing: %w", err)
+ }
+ defer blkdev.Close()
+ blockSize, err := unix.IoctlGetUint32(int(blkdev.Fd()), unix.BLKSSZGET)
+ zeroedBuf := make([]byte, blockSize*100) // Make it faster
+ for {
+ _, err := blkdev.Write(zeroedBuf)
+ if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENOSPC {
+ break
+ }
+ if err != nil {
+ return fmt.Errorf("failed to zero-initalize new encrypted device: %w", err)
+ }
+ }
+ return nil
+}