diff options
Diffstat (limited to 'format/pack/checksum')
| -rw-r--r-- | format/pack/checksum/checksum.go | 108 |
1 files changed, 0 insertions, 108 deletions
diff --git a/format/pack/checksum/checksum.go b/format/pack/checksum/checksum.go deleted file mode 100644 index 7fc1c954..00000000 --- a/format/pack/checksum/checksum.go +++ /dev/null @@ -1,108 +0,0 @@ -// Package checksum provides Git pack/index checksum primitives. -package checksum - -import ( - "bytes" - "fmt" - - "codeberg.org/lindenii/furgit/objectid" -) - -// VerifyPackTrailer verifies one pack trailer hash against the pack payload. -// -// This computes the object hash over all bytes except the trailing hash, so it -// is O(pack size). -func VerifyPackTrailer(data []byte, algo objectid.Algorithm) error { - hashSize := algo.Size() - if hashSize <= 0 { - return objectid.ErrInvalidAlgorithm - } - if len(data) < hashSize { - return fmt.Errorf("format/pack/checksum: pack too short for trailer hash") - } - - hash, err := algo.New() - if err != nil { - return err - } - if _, err := hash.Write(data[:len(data)-hashSize]); err != nil { - return err - } - computed := hash.Sum(nil) - trailer := data[len(data)-hashSize:] - if !bytes.Equal(computed, trailer) { - return fmt.Errorf("format/pack/checksum: pack trailer hash mismatch") - } - return nil -} - -// PackTrailerHash returns the trailer hash bytes from one pack file. -func PackTrailerHash(data []byte, algo objectid.Algorithm) ([]byte, error) { - hashSize := algo.Size() - if hashSize <= 0 { - return nil, objectid.ErrInvalidAlgorithm - } - if len(data) < hashSize { - return nil, fmt.Errorf("format/pack/checksum: pack too short for trailer hash") - } - return data[len(data)-hashSize:], nil -} - -// ParseIdxTrailer parses one idx v2 trailer and returns (packHash, idxHash). -func ParseIdxTrailer(data []byte, algo objectid.Algorithm) ([]byte, []byte, error) { - hashSize := algo.Size() - if hashSize <= 0 { - return nil, nil, objectid.ErrInvalidAlgorithm - } - if len(data) < hashSize*2 { - return nil, nil, fmt.Errorf("format/pack/checksum: idx too short for trailer hashes") - } - packHashOff := len(data) - hashSize*2 - idxHashOff := len(data) - hashSize - return data[packHashOff:idxHashOff], data[idxHashOff:], nil -} - -// VerifyIdxTrailer verifies one idx trailer checksum against preceding bytes. -func VerifyIdxTrailer(data []byte, algo objectid.Algorithm) error { - hashSize := algo.Size() - if hashSize <= 0 { - return objectid.ErrInvalidAlgorithm - } - if len(data) < hashSize*2 { - return fmt.Errorf("format/pack/checksum: idx too short for trailer hashes") - } - - _, idxHash, err := ParseIdxTrailer(data, algo) - if err != nil { - return err - } - hash, err := algo.New() - if err != nil { - return err - } - if _, err := hash.Write(data[:len(data)-hashSize]); err != nil { - return err - } - computed := hash.Sum(nil) - if !bytes.Equal(computed, idxHash) { - return fmt.Errorf("format/pack/checksum: idx trailer hash mismatch") - } - return nil -} - -// VerifyPackMatchesIdx compares a pack trailer hash with one idx-recorded pack -// hash. -func VerifyPackMatchesIdx(packData, idxData []byte, algo objectid.Algorithm) error { - packTrailerHash, err := PackTrailerHash(packData, algo) - if err != nil { - return err - } - idxPackHash, _, err := ParseIdxTrailer(idxData, algo) - if err != nil { - return err - } - if !bytes.Equal(packTrailerHash, idxPackHash) { - return fmt.Errorf("format/pack/checksum: pack hash does not match idx") - } - return nil -} |
