libgocryptfs/internal/contentenc/content.go

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// Package contentenc encrypts and decrypts file blocks.
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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package contentenc
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import (
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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"bytes"
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"encoding/binary"
"encoding/hex"
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"errors"
"log"
"runtime"
"sync"
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"github.com/rfjakob/gocryptfs/internal/cryptocore"
"github.com/rfjakob/gocryptfs/internal/stupidgcm"
"github.com/rfjakob/gocryptfs/internal/tlog"
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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)
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// NonceMode determines how nonces are created.
type NonceMode int
const (
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// DefaultBS is the default plaintext block size
DefaultBS = 4096
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// DefaultIVBits is the default length of IV, in bits.
// We always use 128-bit IVs for file content, but the
// master key in the config file is encrypted with a 96-bit IV for
// gocryptfs v1.2 and earlier. v1.3 switched to 128 bit.
DefaultIVBits = 128
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_ = iota // skip zero
// RandomNonce chooses a random nonce.
RandomNonce NonceMode = iota
// ReverseDeterministicNonce chooses a deterministic nonce, suitable for
// use in reverse mode.
ReverseDeterministicNonce NonceMode = iota
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// ExternalNonce derives a nonce from external sources.
ExternalNonce NonceMode = iota
)
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// ContentEnc is used to encipher and decipher file content.
type ContentEnc struct {
// Cryptographic primitives
cryptoCore *cryptocore.CryptoCore
// Plaintext block size
plainBS uint64
// Ciphertext block size
cipherBS uint64
// All-zero block of size cipherBS, for fast compares
allZeroBlock []byte
// All-zero block of size IVBitLen/8, for fast compares
allZeroNonce []byte
// Force decode even if integrity check fails (openSSL only)
forceDecode bool
}
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// New returns an initialized ContentEnc instance.
func New(cc *cryptocore.CryptoCore, plainBS uint64, forceDecode bool) *ContentEnc {
cipherBS := plainBS + uint64(cc.IVLen) + cryptocore.AuthTagLen
return &ContentEnc{
cryptoCore: cc,
plainBS: plainBS,
cipherBS: cipherBS,
allZeroBlock: make([]byte, cipherBS),
allZeroNonce: make([]byte, cc.IVLen),
forceDecode: forceDecode,
}
}
// PlainBS returns the plaintext block size
func (be *ContentEnc) PlainBS() uint64 {
return be.plainBS
}
// CipherBS returns the ciphertext block size
func (be *ContentEnc) CipherBS() uint64 {
return be.cipherBS
}
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// DecryptBlocks decrypts a number of blocks
func (be *ContentEnc) DecryptBlocks(ciphertext []byte, firstBlockNo uint64, fileID []byte) ([]byte, error) {
cBuf := bytes.NewBuffer(ciphertext)
var err error
var pBuf bytes.Buffer
for cBuf.Len() > 0 {
cBlock := cBuf.Next(int(be.cipherBS))
var pBlock []byte
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pBlock, err = be.DecryptBlock(cBlock, firstBlockNo, fileID)
if err != nil {
if be.forceDecode && err == stupidgcm.ErrAuth {
tlog.Warn.Printf("DecryptBlocks: authentication failure in block #%d, overriden by forcedecode", firstBlockNo)
} else {
break
}
}
pBuf.Write(pBlock)
firstBlockNo++
}
return pBuf.Bytes(), err
}
// DecryptBlock - Verify and decrypt GCM block
//
// Corner case: A full-sized block of all-zero ciphertext bytes is translated
// to an all-zero plaintext block, i.e. file hole passtrough.
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func (be *ContentEnc) DecryptBlock(ciphertext []byte, blockNo uint64, fileID []byte) ([]byte, error) {
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// Empty block?
if len(ciphertext) == 0 {
return ciphertext, nil
}
// All-zero block?
if bytes.Equal(ciphertext, be.allZeroBlock) {
tlog.Debug.Printf("DecryptBlock: file hole encountered")
return make([]byte, be.plainBS), nil
}
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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if len(ciphertext) < be.cryptoCore.IVLen {
tlog.Warn.Printf("DecryptBlock: Block is too short: %d bytes", len(ciphertext))
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return nil, errors.New("Block is too short")
}
// Extract nonce
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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nonce := ciphertext[:be.cryptoCore.IVLen]
if bytes.Equal(nonce, be.allZeroNonce) {
// Bug in tmpfs?
// https://github.com/rfjakob/gocryptfs/issues/56
// http://www.spinics.net/lists/kernel/msg2370127.html
return nil, errors.New("all-zero nonce")
}
ciphertextOrig := ciphertext
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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ciphertext = ciphertext[be.cryptoCore.IVLen:]
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// Decrypt
var plaintext []byte
aData := make([]byte, 8)
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aData = append(aData, fileID...)
binary.BigEndian.PutUint64(aData, blockNo)
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plaintext, err := be.cryptoCore.AEADCipher.Open(plaintext, nonce, ciphertext, aData)
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if err != nil {
tlog.Warn.Printf("DecryptBlock: %s, len=%d", err.Error(), len(ciphertextOrig))
tlog.Debug.Println(hex.Dump(ciphertextOrig))
if be.forceDecode && err == stupidgcm.ErrAuth {
return plaintext, err
}
return nil, err
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}
return plaintext, nil
}
// At some point, splitting the ciphertext into more groups will not improve
// performance, as spawning goroutines comes at a cost.
// 2 seems to work ok for now.
const encryptMaxSplit = 2
// EncryptBlocks is like EncryptBlock but takes multiple plaintext blocks.
func (be *ContentEnc) EncryptBlocks(plaintextBlocks [][]byte, firstBlockNo uint64, fileID []byte) []byte {
ciphertextBlocks := make([][]byte, len(plaintextBlocks))
// For large writes, we parallelize encryption.
if len(plaintextBlocks) >= 32 {
ncpu := runtime.NumCPU()
if ncpu > encryptMaxSplit {
ncpu = encryptMaxSplit
}
groupSize := len(plaintextBlocks) / ncpu
var wg sync.WaitGroup
for i := 0; i < ncpu; i++ {
wg.Add(1)
go func(i int) {
low := i * groupSize
high := (i + 1) * groupSize
if i == ncpu-1 {
// Last group, pick up any left-over blocks
high = len(plaintextBlocks)
}
be.doEncryptBlocks(plaintextBlocks[low:high], ciphertextBlocks[low:high], firstBlockNo+uint64(low), fileID)
wg.Done()
}(i)
}
wg.Wait()
} else {
be.doEncryptBlocks(plaintextBlocks, ciphertextBlocks, firstBlockNo, fileID)
}
// Concatenate ciphertext into a single byte array.
// Size the output buffer for the maximum possible size (all blocks complete)
// to prevent further allocations in out.Write()
tmp := make([]byte, len(plaintextBlocks)*int(be.CipherBS()))
out := bytes.NewBuffer(tmp[:0])
for _, v := range ciphertextBlocks {
out.Write(v)
}
return out.Bytes()
}
// doEncryptBlocks is called by EncryptBlocks to do the actual encryption work
func (be *ContentEnc) doEncryptBlocks(in [][]byte, out [][]byte, firstBlockNo uint64, fileID []byte) {
for i, v := range in {
out[i] = be.EncryptBlock(v, firstBlockNo+uint64(i), fileID)
}
}
// EncryptBlock - Encrypt plaintext using a random nonce.
// blockNo and fileID are used as associated data.
// The output is nonce + ciphertext + tag.
func (be *ContentEnc) EncryptBlock(plaintext []byte, blockNo uint64, fileID []byte) []byte {
// Get a fresh random nonce
nonce := be.cryptoCore.IVGenerator.Get()
return be.doEncryptBlock(plaintext, blockNo, fileID, nonce)
}
// EncryptBlockNonce - Encrypt plaintext using a nonce chosen by the caller.
// blockNo and fileID are used as associated data.
// The output is nonce + ciphertext + tag.
// This function can only be used in SIV mode.
func (be *ContentEnc) EncryptBlockNonce(plaintext []byte, blockNo uint64, fileID []byte, nonce []byte) []byte {
if be.cryptoCore.AEADBackend != cryptocore.BackendAESSIV {
log.Panic("deterministic nonces are only secure in SIV mode")
}
return be.doEncryptBlock(plaintext, blockNo, fileID, nonce)
}
// doEncryptBlock is the backend for EncryptBlock and EncryptBlockNonce.
// blockNo and fileID are used as associated data.
// The output is nonce + ciphertext + tag.
func (be *ContentEnc) doEncryptBlock(plaintext []byte, blockNo uint64, fileID []byte, nonce []byte) []byte {
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// Empty block?
if len(plaintext) == 0 {
return plaintext
}
if len(nonce) != be.cryptoCore.IVLen {
log.Panic("wrong nonce length")
}
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// Authenticate block with block number and file ID
aData := make([]byte, 8)
binary.BigEndian.PutUint64(aData, blockNo)
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aData = append(aData, fileID...)
// Encrypt plaintext and append to nonce
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ciphertext := be.cryptoCore.AEADCipher.Seal(nonce, nonce, plaintext, aData)
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return ciphertext
}
// MergeBlocks - Merge newData into oldData at offset
// New block may be bigger than both newData and oldData
Major refactoring: Split up "cryptfs" into several internal packages "git status" for reference: deleted: cryptfs/cryptfs.go deleted: cryptfs/names_core.go modified: integration_tests/cli_test.go modified: integration_tests/helpers.go renamed: cryptfs/config_file.go -> internal/configfile/config_file.go renamed: cryptfs/config_test.go -> internal/configfile/config_test.go renamed: cryptfs/config_test/.gitignore -> internal/configfile/config_test/.gitignore renamed: cryptfs/config_test/PlaintextNames.conf -> internal/configfile/config_test/PlaintextNames.conf renamed: cryptfs/config_test/StrangeFeature.conf -> internal/configfile/config_test/StrangeFeature.conf renamed: cryptfs/config_test/v1.conf -> internal/configfile/config_test/v1.conf renamed: cryptfs/config_test/v2.conf -> internal/configfile/config_test/v2.conf renamed: cryptfs/kdf.go -> internal/configfile/kdf.go renamed: cryptfs/kdf_test.go -> internal/configfile/kdf_test.go renamed: cryptfs/cryptfs_content.go -> internal/contentenc/content.go new file: internal/contentenc/content_api.go renamed: cryptfs/content_test.go -> internal/contentenc/content_test.go renamed: cryptfs/file_header.go -> internal/contentenc/file_header.go renamed: cryptfs/intrablock.go -> internal/contentenc/intrablock.go renamed: cryptfs/address_translation.go -> internal/contentenc/offsets.go new file: internal/cryptocore/crypto_api.go renamed: cryptfs/gcm_go1.4.go -> internal/cryptocore/gcm_go1.4.go renamed: cryptfs/gcm_go1.5.go -> internal/cryptocore/gcm_go1.5.go renamed: cryptfs/nonce.go -> internal/cryptocore/nonce.go renamed: cryptfs/openssl_aead.go -> internal/cryptocore/openssl_aead.go renamed: cryptfs/openssl_benchmark.bash -> internal/cryptocore/openssl_benchmark.bash renamed: cryptfs/openssl_test.go -> internal/cryptocore/openssl_test.go new file: internal/nametransform/name_api.go new file: internal/nametransform/names_core.go renamed: cryptfs/names_diriv.go -> internal/nametransform/names_diriv.go renamed: cryptfs/names_noiv.go -> internal/nametransform/names_noiv.go renamed: cryptfs/names_test.go -> internal/nametransform/names_test.go new file: internal/nametransform/pad16.go renamed: cryptfs/log.go -> internal/toggledlog/log.go renamed: cryptfs/log_go1.4.go -> internal/toggledlog/log_go1.4.go renamed: cryptfs/log_go1.5.go -> internal/toggledlog/log_go1.5.go modified: main.go modified: masterkey.go modified: pathfs_frontend/file.go modified: pathfs_frontend/file_holes.go modified: pathfs_frontend/fs.go modified: pathfs_frontend/fs_dir.go modified: pathfs_frontend/names.go modified: test.bash
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func (be *ContentEnc) MergeBlocks(oldData []byte, newData []byte, offset int) []byte {
// Make block of maximum size
out := make([]byte, be.plainBS)
// Copy old and new data into it
copy(out, oldData)
l := len(newData)
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copy(out[offset:offset+l], newData)
// Crop to length
outLen := len(oldData)
newLen := offset + len(newData)
if outLen < newLen {
outLen = newLen
}
return out[0:outLen]
}