libgocryptfs/internal/contentenc/intrablock.go

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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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// IntraBlock identifies a part of a file block
type IntraBlock struct {
// BlockNo is the block number in the file
BlockNo uint64
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// Skip is an offset into the block payload
// In forward mode: block plaintext
// In reverse mode: offset into block ciphertext. Takes the header into
// account.
Skip uint64
// Length of payload data in this block
// In forward mode: length of the plaintext
// In reverse mode: length of the ciphertext. Takes header and trailer into
// account.
Length uint64
fs *ContentEnc
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}
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// IsPartial - is the block partial? This means we have to do read-modify-write.
func (ib *IntraBlock) IsPartial() bool {
if ib.Skip > 0 || ib.Length < ib.fs.plainBS {
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return true
}
return false
}
// BlockCipherOff returns the ciphertext offset corresponding to BlockNo
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func (ib *IntraBlock) BlockCipherOff() (offset uint64) {
return ib.fs.BlockNoToCipherOff(ib.BlockNo)
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}
// BlockPlainOff returns the plaintext offset corresponding to BlockNo
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func (ib *IntraBlock) BlockPlainOff() (offset uint64) {
return ib.fs.BlockNoToPlainOff(ib.BlockNo)
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}
// CropBlock - crop a potentially larger plaintext block down to the relevant part
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func (ib *IntraBlock) CropBlock(d []byte) []byte {
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lenHave := len(d)
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lenWant := int(ib.Skip + ib.Length)
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if lenHave < lenWant {
return d[ib.Skip:lenHave]
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}
return d[ib.Skip:lenWant]
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}
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// JointCiphertextRange is the ciphertext range corresponding to the sum of all
// "blocks" (complete blocks)
func (ib *IntraBlock) JointCiphertextRange(blocks []IntraBlock) (offset uint64, length uint64) {
firstBlock := blocks[0]
lastBlock := blocks[len(blocks)-1]
offset = ib.fs.BlockNoToCipherOff(firstBlock.BlockNo)
offsetLast := ib.fs.BlockNoToCipherOff(lastBlock.BlockNo)
length = offsetLast + ib.fs.cipherBS - offset
return offset, length
}
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// JointPlaintextRange is the plaintext range corresponding to the sum of all
// "blocks" (complete blocks)
func JointPlaintextRange(blocks []IntraBlock) (offset uint64, length uint64) {
firstBlock := blocks[0]
lastBlock := blocks[len(blocks)-1]
offset = firstBlock.BlockPlainOff()
length = lastBlock.BlockPlainOff() + lastBlock.fs.PlainBS() - offset
return offset, length
}