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Add support for json file signing
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@dhaavi
dhaavi committed Nov 8, 2024
1 parent 4fbce7d commit 4c4b447
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Showing 4 changed files with 215 additions and 25 deletions.
98 changes: 90 additions & 8 deletions filesig/json.go
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package filesig

import (
"encoding/base64"
"errors"
"fmt"

Expand All @@ -9,7 +10,9 @@ import (
"github.com/tidwall/sjson"
"golang.org/x/exp/slices"

"github.com/safing/jess"
"github.com/safing/jess/lhash"
"github.com/safing/structures/dsd"
)

// JSON file metadata keys.
Expand All @@ -32,10 +35,10 @@ func AddJSONChecksum(data []byte) ([]byte, error) {
checksums = append(checksums, h.Base58())

// Sort and deduplicate checksums and sigs.
slices.Sort[[]string, string](checksums)
checksums = slices.Compact[[]string, string](checksums)
slices.Sort[[]string, string](signatures)
signatures = slices.Compact[[]string, string](signatures)
slices.Sort(checksums)
checksums = slices.Compact(checksums)
slices.Sort(signatures)
signatures = slices.Compact(signatures)

// Add metadata and return.
return jsonAddMeta(content, checksums, signatures)
Expand Down Expand Up @@ -72,6 +75,86 @@ func VerifyJSONChecksum(data []byte) error {
return nil
}

func AddJSONSignature(data []byte, envelope *jess.Envelope, trustStore jess.TrustStore) (signedData []byte, err error) {
// Create session.
session, err := envelope.Correspondence(trustStore)
if err != nil {
return nil, fmt.Errorf("invalid signing envelope: %w", err)
}

// Check if the envelope is suitable for signing.
if err := envelope.Suite().Provides.CheckComplianceTo(fileSigRequirements); err != nil {
return nil, fmt.Errorf("envelope not suitable for signing: %w", err)
}

// Extract content and metadata from json.
content, checksums, signatures, err := jsonSplit(data)
if err != nil {
return nil, fmt.Errorf("invalid json structure: %w", err)
}

// Sign data.
letter, err := session.Close(content)
if err != nil {
return nil, fmt.Errorf("sign: %w", err)
}

// Serialize signature and add it.
letter.Data = nil
sig, err := letter.ToDSD(dsd.CBOR)
if err != nil {
return nil, fmt.Errorf("serialize sig: %w", err)
}
signatures = append(signatures, base64.RawURLEncoding.EncodeToString(sig))

// Sort and deduplicate checksums and sigs.
slices.Sort(checksums)
checksums = slices.Compact(checksums)
slices.Sort(signatures)
signatures = slices.Compact(signatures)

// Add metadata and return.
return jsonAddMeta(data, checksums, signatures)
}

func VerifyJSONSignature(data []byte, trustStore jess.TrustStore) (err error) {
// Extract content and metadata from json.
content, _, signatures, err := jsonSplit(data)
if err != nil {
return fmt.Errorf("invalid json structure: %w", err)
}

var signaturesVerified int
for i, sig := range signatures {
// Deserialize signature.
sigData, err := base64.RawURLEncoding.DecodeString(sig)
if err != nil {
return fmt.Errorf("signature %d malformed: %w", i+1, err)
}
letter := &jess.Letter{}
_, err = dsd.Load(sigData, letter)
if err != nil {
return fmt.Errorf("signature %d malformed: %w", i+1, err)
}

// Verify signature.
letter.Data = content
err = letter.Verify(fileSigRequirements, trustStore)
if err != nil {
return fmt.Errorf("signature %d invalid: %w", i+1, err)
}

signaturesVerified++
}

// Fail when no signatures were verified.
if signaturesVerified == 0 {
return ErrSignatureMissing
}

return nil
}

func jsonSplit(data []byte) (
content []byte,
checksums []string,
Expand Down Expand Up @@ -187,10 +270,9 @@ func jsonAddMeta(data []byte, checksums, signatures []string) ([]byte, error) {

// Final pretty print.
data = pretty.PrettyOptions(data, &pretty.Options{
Width: 200, // Must not change!
Prefix: "", // Must not change!
Indent: " ", // Must not change!
SortKeys: true, // Must not change!
Width: 200, // Must not change!
Prefix: "", // Must not change!
Indent: " ", // Must not change!
})

return data, nil
Expand Down
119 changes: 113 additions & 6 deletions filesig/json_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,10 @@ import (
"testing"

"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"

"github.com/safing/jess"
"github.com/safing/jess/tools"
)

func TestJSONChecksums(t *testing.T) {
Expand All @@ -22,9 +26,9 @@ func TestJSONChecksums(t *testing.T) {
`

testJSONWithChecksum, err := AddJSONChecksum([]byte(json))
assert.NoError(t, err, "should be able to add checksum")
require.NoError(t, err, "should be able to add checksum")
assert.Equal(t, jsonWithChecksum, string(testJSONWithChecksum), "should match")
assert.NoError(t,
require.NoError(t,
VerifyJSONChecksum(testJSONWithChecksum),
"checksum should be correct",
)
Expand All @@ -33,7 +37,7 @@ func TestJSONChecksums(t *testing.T) {
"c": 1, "a":"b",
"_jess-checksum": "ZwtAd75qvioh6uf1NAq64KRgTbqeehFVYmhLmrwu1s7xJo"
}`
assert.NoError(t,
require.NoError(t,
VerifyJSONChecksum([]byte(jsonWithChecksum)),
"checksum should be correct",
)
Expand All @@ -48,7 +52,7 @@ func TestJSONChecksums(t *testing.T) {
"c": 1
}
`
assert.NoError(t,
require.NoError(t,
VerifyJSONChecksum([]byte(jsonWithMultiChecksum)),
"checksum should be correct",
)
Expand All @@ -61,9 +65,9 @@ func TestJSONChecksums(t *testing.T) {
`

testJSONWithMultiChecksum, err := AddJSONChecksum([]byte(jsonWithMultiChecksum))
assert.NoError(t, err, "should be able to add checksum")
require.NoError(t, err, "should be able to add checksum")
assert.Equal(t, jsonWithMultiChecksumOutput, string(testJSONWithMultiChecksum), "should match")
assert.NoError(t,
require.NoError(t,
VerifyJSONChecksum(testJSONWithMultiChecksum),
"checksum should be correct",
)
Expand Down Expand Up @@ -117,3 +121,106 @@ func TestJSONChecksums(t *testing.T) {
//
// assert.Error(t, VerifyTextFileChecksum([]byte(textWithFailingChecksums), "#"), "should fail")
}

func TestJSONSignatures(t *testing.T) {
t.Parallel()

// Get tool for key generation.
tool, err := tools.Get("Ed25519")
if err != nil {
t.Fatal(err)
}

// Generate key pair.
s, err := getOrMakeSignet(t, tool.StaticLogic, false, "test-key-jsonsig-1")
if err != nil {
t.Fatal(err)
}
// sBackup, err := s.Backup(true)
// if err != nil {
// t.Fatal(err)
// }
// t.Logf("signet: %s", sBackup)

// Make envelope.
envelope := jess.NewUnconfiguredEnvelope()
envelope.SuiteID = jess.SuiteSignV1
envelope.Senders = []*jess.Signet{s}

// Test 1: Simple json.

json := `{"a": "b", "c": 1}`
testJSONWithSignature, err := AddJSONSignature([]byte(json), envelope, testTrustStore)
require.NoError(t, err, "should be able to add signature")
require.NoError(t,
VerifyJSONSignature(testJSONWithSignature, testTrustStore),
"signature should be valid",
)

// Test 2: Prepared json with signature.

// Load signing key into trust store.
signingKey2, err := jess.SenderFromTextFormat(
"sender:2ZxXzzL3mc3mLPizTUe49zi8Z3NMbDrmmqJ4V9mL4AxefZ1o8pM8wPMuK2uW12Mvd3EJL9wsKTn14BDuqH2AtucvHTAkjDdZZ5YA9Azmji5tLRXmypvSxEj2mxXU3MFXBVdpzPdwRcE4WauLo9ZfQWebznvnatVLwuxmeo17tU2pL7",
)
if err != nil {
t.Fatal(err)
}
rcptKey2, err := signingKey2.AsRecipient()
if err != nil {
t.Fatal(err)
}
if err := testTrustStore.StoreSignet(rcptKey2); err != nil {
t.Fatal(err)
}

// Verify data.
jsonWithSignature := `{
"c":1,"a":"b",
"_jess-signature": "Q6RnVmVyc2lvbgFnU3VpdGVJRGdzaWduX3YxZU5vbmNlRK6e7JhqU2lnbmF0dXJlc4GjZlNjaGVtZWdFZDI1NTE5YklEeBl0ZXN0LXN0YXRpYy1rZXktanNvbnNpZy0xZVZhbHVlWEBPEbeM4_CTl3OhNT2z74h38jIZG5R7BBLDFd6npJ3E-4JqM6TaSMa-2pPEBf3fDNuikR3ak45SekC6Z10uWiEB"
}`
require.NoError(t,
VerifyJSONSignature([]byte(jsonWithSignature), testTrustStore),
"signature should be valid",
)

// Test 3: Add signature to prepared json.

testJSONWithSignature, err = AddJSONSignature([]byte(jsonWithSignature), envelope, testTrustStore)
require.NoError(t, err, "should be able to add signature")
require.NoError(t,
VerifyJSONSignature(testJSONWithSignature, testTrustStore),
"signatures should be valid",
)

// Test 4: Prepared json with multiple signatures.

// Load signing key into trust store.
signingKey3, err := jess.SenderFromTextFormat(
"sender:2ZxXzzL3mc3mLPizTUe49zi8Z3NMbDrmmqJ4V9mL4AxefZ1o8pM8wPMuRAXdZNaPX3B96bhGCpww6TbXJ6WXLHoLwLV196cgdm1BurfTMdjUPa4PUj1KgHuM82b1p8ezQeryzj1CsjeM8KRQdh9YP87gwKpXNmLW5GmUyWG5KxzZ7W",
)
if err != nil {
t.Fatal(err)
}
rcptKey3, err := signingKey3.AsRecipient()
if err != nil {
t.Fatal(err)
}
if err := testTrustStore.StoreSignet(rcptKey3); err != nil {
t.Fatal(err)
}

jsonWithMultiSig := `{
"_jess-signature": [
"Q6RnVmVyc2lvbgFnU3VpdGVJRGdzaWduX3YxZU5vbmNlRK6e7JhqU2lnbmF0dXJlc4GjZlNjaGVtZWdFZDI1NTE5YklEeBl0ZXN0LXN0YXRpYy1rZXktanNvbnNpZy0xZVZhbHVlWEBPEbeM4_CTl3OhNT2z74h38jIZG5R7BBLDFd6npJ3E-4JqM6TaSMa-2pPEBf3fDNuikR3ak45SekC6Z10uWiEB",
"Q6RnVmVyc2lvbgFnU3VpdGVJRGdzaWduX3YxZU5vbmNlRC32oylqU2lnbmF0dXJlc4GjZlNjaGVtZWdFZDI1NTE5YklEeBl0ZXN0LXN0YXRpYy1rZXktanNvbnNpZy0yZVZhbHVlWEDYVHeKaJvzZPOkgC6Tie6x70bNm2jtmJmAwDFDcBL1ddK7pVSefyAPg47xMO7jeucP5bw754P6CdrR5gyANJkM"
],
"a": "b",
"c": 1
}
`
assert.NoError(t,
VerifyJSONSignature([]byte(jsonWithMultiSig), testTrustStore),
"signatures should be valid",
)
}
2 changes: 1 addition & 1 deletion filesig/main.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ func SignFileData(fileHash *lhash.LabeledHash, metaData map[string]string, envel

// Check if the envelope is suitable for signing.
if err := envelope.Suite().Provides.CheckComplianceTo(fileSigRequirements); err != nil {
return nil, nil, fmt.Errorf("envelope not suitable for signing")
return nil, nil, fmt.Errorf("envelope not suitable for signing: %w", err)
}

// Create struct and transform data into serializable format to be signed.
Expand Down
21 changes: 11 additions & 10 deletions filesig/text_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ import (
"testing"

"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)

func TestTextChecksums(t *testing.T) {
Expand All @@ -29,20 +30,20 @@ do_something()
`

testTextWithChecksumAfterComment, err := AddTextFileChecksum([]byte(text), "#", TextPlacementAfterComment)
assert.NoError(t, err, "should be able to add checksum")
require.NoError(t, err, "should be able to add checksum")
assert.Equal(t, textWithChecksumAfterComment, string(testTextWithChecksumAfterComment), "should match")
assert.NoError(t,
require.NoError(t,
VerifyTextFileChecksum(testTextWithChecksumAfterComment, "#"),
"checksum should be correct",
)
assert.NoError(t,
require.NoError(t,
VerifyTextFileChecksum(append(
[]byte("\n\n \r\n"),
testTextWithChecksumAfterComment...,
), "#"),
"checksum should be correct",
)
assert.NoError(t,
require.NoError(t,
VerifyTextFileChecksum(append(
testTextWithChecksumAfterComment,
[]byte("\r\n \n \n")...,
Expand All @@ -62,9 +63,9 @@ do_something()
`

testTextWithChecksumAtTop, err := AddTextFileChecksum([]byte(text), "#", TextPlacementTop)
assert.NoError(t, err, "should be able to add checksum")
require.NoError(t, err, "should be able to add checksum")
assert.Equal(t, textWithChecksumAtTop, string(testTextWithChecksumAtTop), "should match")
assert.NoError(t,
require.NoError(t,
VerifyTextFileChecksum(testTextWithChecksumAtTop, "#"),
"checksum should be correct",
)
Expand All @@ -82,9 +83,9 @@ do_something()
`

testTextWithChecksumAtBottom, err := AddTextFileChecksum([]byte(text), "#", TextPlacementBottom)
assert.NoError(t, err, "should be able to add checksum")
require.NoError(t, err, "should be able to add checksum")
assert.Equal(t, textWithChecksumAtBottom, string(testTextWithChecksumAtBottom), "should match")
assert.NoError(t,
require.NoError(t,
VerifyTextFileChecksum(testTextWithChecksumAtBottom, "#"),
"checksum should be correct",
)
Expand Down Expand Up @@ -119,7 +120,7 @@ do_something()
do_something()
`
testTextWithMultiChecksumOutput, err := AddTextFileChecksum([]byte(textWithMultiChecksum), "#", TextPlacementAfterComment)
assert.NoError(t, err, "should be able to add checksum")
require.NoError(t, err, "should be able to add checksum")
assert.Equal(t, textWithMultiChecksumOutput, string(testTextWithMultiChecksumOutput), "should match")

// Test failing checksums.
Expand All @@ -135,7 +136,7 @@ do_something()
do_something()
`
assert.Error(t, VerifyTextFileChecksum([]byte(textWithFailingChecksums), "#"), "should fail")
require.Error(t, VerifyTextFileChecksum([]byte(textWithFailingChecksums), "#"), "should fail")
}

func TestLineEndDetection(t *testing.T) {
Expand Down

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