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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
package storev1
import (
"fmt"
"strings"
"google.golang.org/protobuf/proto"
"lukechampine.com/blake3"
)
// The size of a directory is calculated by summing up the numbers of
// `directories`, `files` and `symlinks`, and for each directory, its size
// field.
func (d *Directory) Size() uint32 {
var size uint32
size = uint32(len(d.Files) + len(d.Symlinks))
for _, d := range d.Directories {
size += 1 + d.Size
}
return size
}
func (d *Directory) Digest() ([]byte, error) {
b, err := proto.MarshalOptions{
Deterministic: true,
}.Marshal(d)
if err != nil {
return nil, fmt.Errorf("error while marshalling directory: %w", err)
}
h := blake3.New(32, nil)
_, err = h.Write(b)
if err != nil {
return nil, fmt.Errorf("error writing to hasher: %w", err)
}
return h.Sum(nil), nil
}
// isValidName checks a name for validity.
// We disallow slashes, null bytes, '.', '..' and the empty string.
// Depending on the context, a *Node message with an empty string as name is
// allowed, but they don't occur inside a Directory message.
func isValidName(n string) bool {
if n == "" || n == ".." || n == "." || strings.Contains(n, "\x00") || strings.Contains(n, "/") {
return false
}
return true
}
// Validate thecks the Directory message for invalid data, such as:
// - violations of name restrictions
// - invalid digest lengths
// - not properly sorted lists
// - duplicate names in the three lists
func (d *Directory) Validate() error {
// seenNames contains all seen names so far.
// We populate this to ensure node names are unique across all three lists.
seenNames := make(map[string]interface{})
// We also track the last seen name in each of the three lists,
// to ensure nodes are sorted by their names.
var lastDirectoryName, lastFileName, lastSymlinkName string
// helper function to only insert in sorted order.
// used with the three lists above.
// Note this consumes a *pointer to* a string, as it mutates it.
insertIfGt := func(lastName *string, name string) error {
// update if it's greater than the previous name
if name > *lastName {
*lastName = name
return nil
} else {
return fmt.Errorf("%v is not in sorted order", name)
}
}
// insertOnce inserts into seenNames if the key doesn't exist yet.
insertOnce := func(name string) error {
if _, found := seenNames[name]; found {
return fmt.Errorf("duplicate name: %v", name)
}
seenNames[name] = nil
return nil
}
// Loop over all Directories, Files and Symlinks individually.
// Check the name for validity, check a potential digest for length,
// then check for sorting in the current list, and uniqueness across all three lists.
for _, directoryNode := range d.Directories {
directoryName := directoryNode.GetName()
// check name for validity
if !isValidName(directoryName) {
return fmt.Errorf("invalid name for DirectoryNode: %v", directoryName)
}
// check digest to be 32 bytes
digestLen := len(directoryNode.GetDigest())
if digestLen != 32 {
return fmt.Errorf("invalid digest length for DirectoryNode: %d", digestLen)
}
// ensure names are sorted
if err := insertIfGt(&lastDirectoryName, directoryName); err != nil {
return err
}
// add to seenNames
if err := insertOnce(directoryName); err != nil {
return err
}
}
for _, fileNode := range d.Files {
fileName := fileNode.GetName()
// check name for validity
if !isValidName(fileName) {
return fmt.Errorf("invalid name for FileNode: %v", fileName)
}
// check digest to be 32 bytes
digestLen := len(fileNode.GetDigest())
if digestLen != 32 {
return fmt.Errorf("invalid digest length for FileNode: %d", digestLen)
}
// ensure names are sorted
if err := insertIfGt(&lastFileName, fileName); err != nil {
return err
}
// add to seenNames
if err := insertOnce(fileName); err != nil {
return err
}
}
for _, symlinkNode := range d.Symlinks {
symlinkName := symlinkNode.GetName()
// check name for validity
if !isValidName(symlinkName) {
return fmt.Errorf("invalid name for SymlinkNode: %v", symlinkName)
}
// ensure names are sorted
if err := insertIfGt(&lastSymlinkName, symlinkName); err != nil {
return err
}
// add to seenNames
if err := insertOnce(symlinkName); err != nil {
return err
}
}
return nil
}
|
