diff options
Diffstat (limited to 'cryptfs')
| -rw-r--r-- | cryptfs/content_test.go | 26 | ||||
| -rw-r--r-- | cryptfs/cryptfs_content.go | 9 |
2 files changed, 31 insertions, 4 deletions
diff --git a/cryptfs/content_test.go b/cryptfs/content_test.go index 1900818..b53eeeb 100644 --- a/cryptfs/content_test.go +++ b/cryptfs/content_test.go @@ -32,3 +32,29 @@ func TestSplitRange(t *testing.T) { } } } + +func TestCiphertextRange(t *testing.T) { + var ranges []testRange + + ranges = append(ranges, testRange{0, 70000}, + testRange{0, 10}, + testRange{234, 6511}, + testRange{65444, 54}, + testRange{6654, 8945}) + + var key [16]byte + f := NewCryptFS(key, true) + + for _, r := range(ranges) { + alignedOffset, alignedLength, skipBytes := f.CiphertextRange(r.offset, r.length) + if alignedLength < r.length { + t.Fail() + } + if alignedOffset % f.cipherBS != 0 { + t.Fail() + } + if r.offset % f.plainBS != 0 && skipBytes == 0 { + t.Fail() + } + } +} diff --git a/cryptfs/cryptfs_content.go b/cryptfs/cryptfs_content.go index e23d9b5..b9dd61f 100644 --- a/cryptfs/cryptfs_content.go +++ b/cryptfs/cryptfs_content.go @@ -115,7 +115,7 @@ func (be *CryptFS) minu64(x uint64, y uint64) uint64 { // CiphertextRange - Get byte range in backing ciphertext corresponding // to plaintext range. Returns a range aligned to ciphertext blocks. -func (be *CryptFS) CiphertextRange(offset uint64, length uint64) (uint64, uint64, int) { +func (be *CryptFS) CiphertextRange(offset uint64, length uint64) (alignedOffset uint64, alignedLength uint64, skipBytes int) { // Decrypting the ciphertext will yield too many plaintext bytes. Skip this number // of bytes from the front. skip := offset % be.plainBS @@ -123,10 +123,11 @@ func (be *CryptFS) CiphertextRange(offset uint64, length uint64) (uint64, uint64 firstBlockNo := offset / be.plainBS lastBlockNo := ( offset + length - 1 ) / be.plainBS - alignedOffset := firstBlockNo * be.cipherBS - alignedLength := (lastBlockNo - firstBlockNo + 1) * be.cipherBS + alignedOffset = firstBlockNo * be.cipherBS + alignedLength = (lastBlockNo - firstBlockNo + 1) * be.cipherBS - return alignedOffset, alignedLength, int(skip) + skipBytes = int(skip) + return alignedOffset, alignedLength, skipBytes } // Get the byte range in the ciphertext corresponding to blocks |