Files
sqlite3/vfs/adiantum/hbsh.go
Nuno Cruces 32d998c84b Filenames.
2024-07-26 01:23:35 +01:00

280 lines
6.6 KiB
Go

package adiantum
import (
"encoding/binary"
"encoding/hex"
"io"
"github.com/ncruces/go-sqlite3"
"github.com/ncruces/go-sqlite3/internal/util"
"github.com/ncruces/go-sqlite3/vfs"
"lukechampine.com/adiantum/hbsh"
)
type hbshVFS struct {
vfs.VFS
hbsh HBSHCreator
}
func (h *hbshVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
// notest // OpenFilename is called instead
return nil, 0, sqlite3.CANTOPEN
}
func (h *hbshVFS) OpenFilename(name *vfs.Filename, flags vfs.OpenFlag) (file vfs.File, _ vfs.OpenFlag, err error) {
if hf, ok := h.VFS.(vfs.VFSFilename); ok {
file, flags, err = hf.OpenFilename(name, flags)
} else {
file, flags, err = h.VFS.Open(name.String(), flags)
}
// Encrypt everything except super journals and memory files.
if err != nil || flags&(vfs.OPEN_SUPER_JOURNAL|vfs.OPEN_MEMORY) != 0 {
return file, flags, err
}
var hbsh *hbsh.HBSH
if f, ok := name.DatabaseFile().(*hbshFile); ok {
hbsh = f.hbsh
} else {
var key []byte
if params := name.URIParameters(); name == nil {
key = h.hbsh.KDF("") // Temporary files get a random key.
} else if t, ok := params["key"]; ok {
key = []byte(t[0])
} else if t, ok := params["hexkey"]; ok {
key, _ = hex.DecodeString(t[0])
} else if t, ok := params["textkey"]; ok {
key = h.hbsh.KDF(t[0])
} else if flags&vfs.OPEN_MAIN_DB != 0 {
// Main datatabases may have their key specified as a PRAGMA.
return &hbshFile{File: file, reset: h.hbsh}, flags, nil
}
hbsh = h.hbsh.HBSH(key)
}
if hbsh == nil {
return nil, flags, sqlite3.CANTOPEN
}
return &hbshFile{File: file, hbsh: hbsh, reset: h.hbsh}, flags, nil
}
const (
tweakSize = 8
blockSize = 4096
)
type hbshFile struct {
vfs.File
hbsh *hbsh.HBSH
reset HBSHCreator
tweak [tweakSize]byte
block [blockSize]byte
}
func (h *hbshFile) Pragma(name string, value string) (string, error) {
var key []byte
switch name {
case "key":
key = []byte(value)
case "hexkey":
key, _ = hex.DecodeString(value)
case "textkey":
key = h.reset.KDF(value)
default:
if f, ok := h.File.(vfs.FilePragma); ok {
return f.Pragma(name, value)
}
return "", sqlite3.NOTFOUND
}
if h.hbsh = h.reset.HBSH(key); h.hbsh != nil {
return "ok", nil
}
return "", sqlite3.CANTOPEN
}
func (h *hbshFile) ReadAt(p []byte, off int64) (n int, err error) {
if h.hbsh == nil {
// Only OPEN_MAIN_DB can have a missing key.
if off == 0 && len(p) == 100 {
// SQLite is trying to read the header of a database file.
// Pretend the file is empty so the key may specified as a PRAGMA.
return 0, io.EOF
}
return 0, sqlite3.CANTOPEN
}
min := (off) &^ (blockSize - 1) // round down
max := (off + int64(len(p)) + (blockSize - 1)) &^ (blockSize - 1) // round up
// Read one block at a time.
for ; min < max; min += blockSize {
m, err := h.File.ReadAt(h.block[:], min)
if m != blockSize {
return n, err
}
binary.LittleEndian.PutUint64(h.tweak[:], uint64(min))
data := h.hbsh.Decrypt(h.block[:], h.tweak[:])
if off > min {
data = data[off-min:]
}
n += copy(p[n:], data)
}
if n != len(p) {
panic(util.AssertErr())
}
return n, nil
}
func (h *hbshFile) WriteAt(p []byte, off int64) (n int, err error) {
if h.hbsh == nil {
return 0, sqlite3.READONLY
}
min := (off) &^ (blockSize - 1) // round down
max := (off + int64(len(p)) + (blockSize - 1)) &^ (blockSize - 1) // round up
// Write one block at a time.
for ; min < max; min += blockSize {
binary.LittleEndian.PutUint64(h.tweak[:], uint64(min))
data := h.block[:]
if off > min || len(p[n:]) < blockSize {
// Partial block write: read-update-write.
m, err := h.File.ReadAt(h.block[:], min)
if m != blockSize {
if err != io.EOF {
return n, err
}
// Writing past the EOF.
// We're either appending an entirely new block,
// or the final block was only partially written.
// A partially written block can't be decrypted,
// and is as good as corrupt.
// Either way, zero pad the file to the next block size.
clear(data)
} else {
data = h.hbsh.Decrypt(h.block[:], h.tweak[:])
}
if off > min {
data = data[off-min:]
}
}
t := copy(data, p[n:])
h.hbsh.Encrypt(h.block[:], h.tweak[:])
m, err := h.File.WriteAt(h.block[:], min)
if m != blockSize {
return n, err
}
n += t
}
if n != len(p) {
panic(util.AssertErr())
}
return n, nil
}
func (h *hbshFile) Truncate(size int64) error {
size = (size + (blockSize - 1)) &^ (blockSize - 1) // round up
return h.File.Truncate(size)
}
func (h *hbshFile) SectorSize() int {
return lcm(h.File.SectorSize(), blockSize)
}
func (h *hbshFile) DeviceCharacteristics() vfs.DeviceCharacteristic {
return h.File.DeviceCharacteristics() & (0 |
// The only safe flags are these:
vfs.IOCAP_UNDELETABLE_WHEN_OPEN |
vfs.IOCAP_IMMUTABLE |
vfs.IOCAP_BATCH_ATOMIC)
}
// Wrap optional methods.
func (h *hbshFile) SharedMemory() vfs.SharedMemory {
if f, ok := h.File.(vfs.FileSharedMemory); ok {
return f.SharedMemory()
}
return nil
}
func (h *hbshFile) ChunkSize(size int) {
if f, ok := h.File.(vfs.FileChunkSize); ok {
size = (size + (blockSize - 1)) &^ (blockSize - 1) // round up
f.ChunkSize(size)
}
}
func (h *hbshFile) SizeHint(size int64) error {
if f, ok := h.File.(vfs.FileSizeHint); ok {
size = (size + (blockSize - 1)) &^ (blockSize - 1) // round up
return f.SizeHint(size)
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) HasMoved() (bool, error) {
if f, ok := h.File.(vfs.FileHasMoved); ok {
return f.HasMoved()
}
return false, sqlite3.NOTFOUND
}
func (h *hbshFile) Overwrite() error {
if f, ok := h.File.(vfs.FileOverwrite); ok {
return f.Overwrite()
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) CommitPhaseTwo() error {
if f, ok := h.File.(vfs.FileCommitPhaseTwo); ok {
return f.CommitPhaseTwo()
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) BeginAtomicWrite() error {
if f, ok := h.File.(vfs.FileBatchAtomicWrite); ok {
return f.BeginAtomicWrite()
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) CommitAtomicWrite() error {
if f, ok := h.File.(vfs.FileBatchAtomicWrite); ok {
return f.CommitAtomicWrite()
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) RollbackAtomicWrite() error {
if f, ok := h.File.(vfs.FileBatchAtomicWrite); ok {
return f.RollbackAtomicWrite()
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) CheckpointDone() error {
if f, ok := h.File.(vfs.FileCheckpoint); ok {
return f.CheckpointDone()
}
return sqlite3.NOTFOUND
}
func (h *hbshFile) CheckpointStart() error {
if f, ok := h.File.(vfs.FileCheckpoint); ok {
return f.CheckpointStart()
}
return sqlite3.NOTFOUND
}