mirror of
https://github.com/X-Cli/large-file-decrypt.git
synced 2024-12-03 16:12:11 +00:00
initial
This commit is contained in:
Florian Maury
parent
fafbf8460f
commit
b1f60357fa
8 changed files with 427 additions and 1 deletions
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@ -1,2 +1,2 @@
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# large-file-decrypt
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# Large File Decrypt
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Example code for hopefully secure large file decryption
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100
decrypt/decrypt.go
Normal file
100
decrypt/decrypt.go
Normal file
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@ -0,0 +1,100 @@
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package decrypt
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import (
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"errors"
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"fmt"
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"path/filepath"
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"syscall"
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"github.com/X-Cli/large-file-decrypt/utils"
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"github.com/hashicorp/go-multierror"
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"golang.org/x/crypto/nacl/box"
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"golang.org/x/sys/unix"
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)
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func DecryptFile(inputPath, outputPath string, pubKey, privKey *[32]byte) error {
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return decryptFile(inputPath, outputPath, pubKey, privKey).ErrorOrNil()
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}
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func decryptFile(inputPath, outputPath string, pubKey, privKey *[32]byte) (errStack *multierror.Error) {
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inputTempDir := filepath.Dir(inputPath)
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privateEncryptedFile, errs := utils.CreatePrivateCopyOf(inputPath, inputTempDir)
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if errs.ErrorOrNil() != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to create the private copy of the encrypted file: %w", errs))
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return
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}
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privateEncryptedFileClosed := false
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defer func() {
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if !privateEncryptedFileClosed {
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if err := privateEncryptedFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private copy of encrypted file: %w", err))
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}
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}
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}()
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encryptedData, err := utils.GetDataFromFile(privateEncryptedFile)
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to get encrypted data: %w", err))
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return
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}
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privateEncryptedDataFreed := false
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defer func() {
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if !privateEncryptedDataFreed {
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if err := syscall.Munmap(encryptedData); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to munmap encrypted data: %w", err))
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}
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}
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}()
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decryptedSize := len(encryptedData) - box.AnonymousOverhead
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outputTempDir := filepath.Dir(outputPath)
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privateDecryptedFile, err := utils.CreatePrivateFile(outputTempDir, int64(decryptedSize))
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to create private decrypted file: %w", err))
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return
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}
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defer func() {
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if err := privateDecryptedFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private decrypted file: %w", err))
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}
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}()
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decryptedData, err := utils.GetDataFromFile(privateDecryptedFile)
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to mmap decrypted file: %w", err))
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return
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}
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defer func() {
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if err := syscall.Munmap(decryptedData); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to munmap decrypted data: %w", err))
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}
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}()
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if _, ok := box.OpenAnonymous(decryptedData[:0], encryptedData, pubKey, privKey); !ok {
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errStack = multierror.Append(errStack, errors.New("failed to decrypt file"))
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return
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}
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if err := unix.Msync(decryptedData, unix.MS_SYNC); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to flush changes to disk: %w", err))
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return
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}
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// Since in the worst case, we can only copy the private decrypted file to the public file, we release the private encrypted file now, so that the algorithm only uses a maximum of 3 times the size of the encrypted file
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privateEncryptedDataFreed = true
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if err := syscall.Munmap(encryptedData); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to munmap encrypted data: %w", err))
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return
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}
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privateEncryptedFileClosed = true
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if err := privateEncryptedFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private copy of encrypted file: %w", err))
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return
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}
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if err := utils.PublishFile(privateDecryptedFile, outputPath).ErrorOrNil(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to publish decrypted file: %w", err))
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return
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}
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return
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}
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45
decrypt/decrypt_test.go
Normal file
45
decrypt/decrypt_test.go
Normal file
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package decrypt
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import (
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"bytes"
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"crypto/rand"
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"io/ioutil"
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"path"
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"testing"
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"golang.org/x/crypto/nacl/box"
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)
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func TestDecrypt1(t *testing.T) {
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tmpdir := t.TempDir()
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pubKey, privKey, err := box.GenerateKey(rand.Reader)
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if err != nil {
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t.Fatalf("failed to generate keys: %v", err)
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}
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expectedContent := []byte("Geronimo!")
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encryptedContent, err := box.SealAnonymous(nil, expectedContent, pubKey, rand.Reader)
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if err != nil {
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t.Fatalf("failed to encrypt message: %v", err)
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}
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encryptedFilePath := path.Join(tmpdir, "encryptedFile")
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if err := ioutil.WriteFile(encryptedFilePath, encryptedContent, 0o600); err != nil {
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t.Fatalf("failed to initialize encrypted file: %v", err)
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}
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decryptedFilePath := path.Join(tmpdir, "decryptedFile")
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if err := DecryptFile(encryptedFilePath, decryptedFilePath, pubKey, privKey); err != nil {
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t.Fatalf("failed to decrypt file: %v", err)
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}
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decryptedContent, err := ioutil.ReadFile(decryptedFilePath)
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if err != nil {
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t.Fatalf("failed to read decrypted file: %v", err)
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}
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if !bytes.Equal(expectedContent, decryptedContent) {
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t.Fatalf("mismatched content: expected %v, found %v", expectedContent, decryptedContent)
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}
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}
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102
encrypt/encrypt.go
Normal file
102
encrypt/encrypt.go
Normal file
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package encrypt
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import (
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"crypto/rand"
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"fmt"
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"io"
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"path/filepath"
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"syscall"
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"github.com/X-Cli/large-file-decrypt/utils"
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"github.com/hashicorp/go-multierror"
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"golang.org/x/crypto/nacl/box"
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"golang.org/x/sys/unix"
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)
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func EncryptFile(inputPath, outputPath string, pubKey *[32]byte) error {
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return encryptFile(inputPath, outputPath, pubKey, rand.Reader).ErrorOrNil()
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}
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func encryptFile(inputPath, outputPath string, pubKey *[32]byte, cryptoReader io.Reader) (errStack *multierror.Error) {
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inputTempDir := filepath.Dir(inputPath)
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privateClearFile, errs := utils.CreatePrivateCopyOf(inputPath, inputTempDir)
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if errs.ErrorOrNil() != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to acquire a private copy of %q: %w", inputPath, errs))
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return
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}
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privateClearFileClosed := false
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defer func() {
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if !privateClearFileClosed {
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if err := privateClearFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private copy of %q: %w", inputPath, err))
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}
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}
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}()
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clearData, err := utils.GetDataFromFile(privateClearFile)
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to get data from private copy: %w", err))
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return
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}
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clearDataFreed := false
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defer func() {
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if !clearDataFreed {
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if err := syscall.Munmap(clearData); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to munmap clear data: %w", err))
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}
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}
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}()
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outputTempDir := filepath.Dir(outputPath)
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encryptedSize := len(clearData) + box.AnonymousOverhead
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privateEncryptedFile, err := utils.CreatePrivateFile(outputTempDir, int64(encryptedSize))
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to create private encrypted file: %w", err))
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return
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}
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defer func() {
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if err := privateEncryptedFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private encrypted file: %w", err))
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}
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}()
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encryptedData, err := utils.GetDataFromFile(privateEncryptedFile)
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to get data from encrypted file: %w", err))
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return
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}
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defer func() {
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if err := syscall.Munmap(encryptedData); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to release encrypted data: %w", err))
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}
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}()
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if _, err := box.SealAnonymous(encryptedData[:0], clearData, pubKey, cryptoReader); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to seal data: %w", err))
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return
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}
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if err := unix.Msync(encryptedData, unix.MS_SYNC); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to flush encrypted data on disk: %w", err))
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return
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}
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// Releasing private clear text resources since they are no longer needed and they may occupy resources if file clone was not possible
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clearDataFreed = true
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if err := syscall.Munmap(clearData); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to get data from private copy: %w", err))
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return
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}
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privateClearFileClosed = true
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if err := privateClearFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private copy of %q: %w", inputPath, err))
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return
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}
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if err := utils.PublishFile(privateEncryptedFile, outputPath); err.ErrorOrNil() != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to publish encrypted file: %w", err))
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return
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}
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return
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}
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44
encrypt/encrypt_test.go
Normal file
44
encrypt/encrypt_test.go
Normal file
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@ -0,0 +1,44 @@
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package encrypt
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import (
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"bytes"
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"io/ioutil"
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"path"
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"testing"
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"golang.org/x/crypto/nacl/box"
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)
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func TestEncrypt(t *testing.T) {
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tmpdir := t.TempDir()
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var constantRandom [512]byte
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randReader := bytes.NewBuffer(constantRandom[:])
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clearFile := path.Join(tmpdir, "clear")
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encryptedFile := path.Join(tmpdir, "encrypted")
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clearText := []byte("Geronimo!")
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if err := ioutil.WriteFile(clearFile, clearText, 0o600); err != nil {
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t.Fatalf("failed to write cleartext file: %v", err)
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}
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pubKey, _, err := box.GenerateKey(randReader)
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if err != nil {
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t.Fatalf("failed to generate keys: %v", err)
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}
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if err := encryptFile(clearFile, encryptedFile, pubKey, randReader); err != nil {
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t.Fatalf("failed to encrypt file: %v", err)
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}
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cipherText, err := ioutil.ReadFile(encryptedFile)
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if err != nil {
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t.Fatalf("failed to read encrypted file: %v", err)
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}
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expectedCiphertext := []byte{47, 229, 125, 163, 71, 205, 98, 67, 21, 40, 218, 172, 95, 187, 41, 7, 48, 255, 246, 132, 175, 196, 207, 194, 237, 144, 153, 95, 88, 203, 59, 116, 83, 218, 223, 164, 117, 110, 80, 197, 138, 128, 169, 16, 149, 74, 20, 245, 10, 169, 53, 61, 119, 218, 240, 50, 92}
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if !bytes.Equal(expectedCiphertext, cipherText) {
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t.Fatalf("unexpected ciphertext: expected %v; found %v", expectedCiphertext, cipherText)
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}
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}
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9
go.mod
Normal file
9
go.mod
Normal file
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@ -0,0 +1,9 @@
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module github.com/X-Cli/large-file-decrypt
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go 1.15
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require (
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github.com/hashicorp/go-multierror v1.1.1
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golang.org/x/crypto v0.0.0-20211215153901-e495a2d5b3d3
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golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e
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)
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15
go.sum
Normal file
15
go.sum
Normal file
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@ -0,0 +1,15 @@
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github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
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github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
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github.com/hashicorp/go-multierror v1.1.1 h1:H5DkEtf6CXdFp0N0Em5UCwQpXMWke8IA0+lD48awMYo=
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github.com/hashicorp/go-multierror v1.1.1/go.mod h1:iw975J/qwKPdAO1clOe2L8331t/9/fmwbPZ6JB6eMoM=
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golang.org/x/crypto v0.0.0-20211215153901-e495a2d5b3d3 h1:0es+/5331RGQPcXlMfP+WrnIIS6dNnNRe0WB02W0F4M=
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golang.org/x/crypto v0.0.0-20211215153901-e495a2d5b3d3/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
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golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
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golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
|
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golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
|
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golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
|
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golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e h1:fLOSk5Q00efkSvAm+4xcoXD+RRmLmmulPn5I3Y9F2EM=
|
||||
golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
|
||||
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
|
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golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
|
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golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
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111
utils/utils.go
Normal file
111
utils/utils.go
Normal file
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@ -0,0 +1,111 @@
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package utils
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import (
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"fmt"
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"io"
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"os"
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"syscall"
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|
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"github.com/hashicorp/go-multierror"
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"golang.org/x/sys/unix"
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)
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func CreatePrivateCopyOf(inputPath, tempDir string) (privateFile *os.File, errStack *multierror.Error) {
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inputFile, err := os.Open(inputPath)
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to open file %q: %w", inputPath, err))
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return
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}
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defer func() {
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if err := inputFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close file %q: %w", inputPath, err))
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}
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}()
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privateFileFd, err := unix.Open(tempDir, unix.O_RDWR|unix.O_TMPFILE, 0o600)
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if err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to open private file: %w", err))
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return
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}
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privateFile = os.NewFile(uintptr(privateFileFd), "")
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defer func() {
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if errStack.ErrorOrNil() != nil {
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if err := privateFile.Close(); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to close private copy: %w", err))
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}
|
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}
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}()
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if err := unix.IoctlFileClone(int(privateFile.Fd()), int(inputFile.Fd())); err != nil {
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if err != syscall.EOPNOTSUPP && err != syscall.EINVAL {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to clone file: %w", err))
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return
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}
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if _, err := io.Copy(privateFile, inputFile); err != nil {
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errStack = multierror.Append(errStack, fmt.Errorf("failed to copy file: %w", err))
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return
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}
|
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}
|
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return
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}
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func GetDataFromFile(privateEncryptedFile *os.File) (data []byte, err error) {
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fs, err := privateEncryptedFile.Stat()
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if err != nil {
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return nil, fmt.Errorf("failed to stat(2) private copy of encrypted file: %w", err)
|
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}
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data, err = syscall.Mmap(int(privateEncryptedFile.Fd()), 0, int(fs.Size()), syscall.PROT_WRITE|syscall.PROT_READ, syscall.MAP_SHARED)
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if err != nil {
|
||||
return nil, fmt.Errorf("failed to mmap(2) private copy of encrypted file: %w", err)
|
||||
}
|
||||
return data, nil
|
||||
}
|
||||
|
||||
func CreatePrivateFile(tempDir string, size int64) (*os.File, error) {
|
||||
privateFileFd, err := unix.Open(tempDir, unix.O_RDWR|unix.O_TMPFILE, 0o600)
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("failed to create private file: %w", err)
|
||||
}
|
||||
privateFile := os.NewFile(uintptr(privateFileFd), "")
|
||||
|
||||
if err := syscall.Fallocate(int(privateFile.Fd()), 0, 0, size); err != nil {
|
||||
var errStack error = err
|
||||
if err := privateFile.Close(); err != nil {
|
||||
errStack = multierror.Append(errStack, err)
|
||||
}
|
||||
return nil, errStack
|
||||
}
|
||||
return privateFile, nil
|
||||
}
|
||||
|
||||
func PublishFile(privateDecryptedFile *os.File, outputPath string) (errStack *multierror.Error) {
|
||||
if err := unix.Linkat(int(privateDecryptedFile.Fd()), "", 0, outputPath, unix.AT_EMPTY_PATH); err == nil {
|
||||
return
|
||||
} else if err != syscall.ENOENT {
|
||||
// ENOENT is returned if CAP_DAC_READ_SEARCH is not effective
|
||||
errStack = multierror.Append(errStack, fmt.Errorf("failed to call linkat: %w", err))
|
||||
return
|
||||
}
|
||||
outputFile, err := os.OpenFile(outputPath, os.O_WRONLY|os.O_CREATE, 0o600)
|
||||
if err != nil {
|
||||
errStack = multierror.Append(errStack, fmt.Errorf("failed to create output file: %w", err))
|
||||
return
|
||||
}
|
||||
defer func() {
|
||||
if err := outputFile.Close(); err != nil {
|
||||
errStack = multierror.Append(errStack, fmt.Errorf("failed to close file %q: %w", outputPath, err))
|
||||
}
|
||||
}()
|
||||
if err := unix.IoctlFileClone(int(outputFile.Fd()), int(privateDecryptedFile.Fd())); err == nil {
|
||||
return
|
||||
} else if err != syscall.EOPNOTSUPP && err != syscall.EINVAL {
|
||||
errStack = multierror.Append(errStack, fmt.Errorf("failed to clone file %w", err))
|
||||
return
|
||||
}
|
||||
if _, err := io.Copy(outputFile, privateDecryptedFile); err != nil {
|
||||
errStack = multierror.Append(errStack, fmt.Errorf("failed to copy into public decrypted file: %w", err))
|
||||
return
|
||||
}
|
||||
return
|
||||
}
|
||||
Loading…
Reference in a new issue