1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
package read
import (
"bytes"
"fmt"
"io"
"codeberg.org/lindenii/furgit/objectid"
)
// HashVersion returns the commit-graph hash version.
func (reader *Reader) HashVersion() uint8 {
return reader.hashVersion
}
func validateChainBaseHashes(algo objectid.Algorithm, chain []string, idx int, graph *layer) error {
if idx == 0 {
if len(graph.chunkBaseGraphs) != 0 {
return &MalformedError{Path: graph.path, Reason: "unexpected BASE chunk in first graph"}
}
return nil
}
hashSize := algo.Size()
expectedLen := idx * hashSize
if len(graph.chunkBaseGraphs) != expectedLen {
return &MalformedError{
Path: graph.path,
Reason: fmt.Sprintf("BASE chunk length %d does not match expected %d", len(graph.chunkBaseGraphs), expectedLen),
}
}
for i := range idx {
start := i * hashSize
end := start + hashSize
baseHash, err := objectid.FromBytes(algo, graph.chunkBaseGraphs[start:end])
if err != nil {
return err
}
if baseHash.String() != chain[i] {
return &MalformedError{
Path: graph.path,
Reason: fmt.Sprintf("BASE chunk mismatch at index %d", i),
}
}
}
return nil
}
func verifyTrailerHash(data []byte, algo objectid.Algorithm, path string) error {
hashSize := algo.Size()
if len(data) < hashSize {
return &MalformedError{Path: path, Reason: "file too short for trailer"}
}
hashImpl, err := algo.New()
if err != nil {
return err
}
_, err = io.Copy(hashImpl, bytes.NewReader(data[:len(data)-hashSize]))
if err != nil {
return err
}
got := hashImpl.Sum(nil)
want := data[len(data)-hashSize:]
if !bytes.Equal(got, want) {
return &MalformedError{Path: path, Reason: "trailer hash mismatch"}
}
return nil
}
|
