crypto/canonicaljson: disable old code entirely when jsonv2 is enabled

tulir · tulir · commit 05c4399c1349 · 2026-05-14T17:56:02.000+03:00
diff --git a/bridgev2/database/ghost.go b/bridgev2/database/ghost.go
@@ -33,14 +33,14 @@ func (ep *ExtraProfile) Set(key string, value any) error {
 	if key == "displayname" || key == "avatar_url" {
 		return fmt.Errorf("cannot set reserved profile key %q", key)
 	}
-	marshaled, err := json.Marshal(value)
+	marshaled, err := canonicaljson.Marshal(value)
 	if err != nil {
 		return err
 	}
 	if *ep == nil {
 		*ep = make(ExtraProfile)
 	}
-	(*ep)[key] = canonicaljson.CanonicalJSONAssumeValid(marshaled)
+	(*ep)[key] = marshaled
 	return nil
 }
 
@@ -49,11 +49,9 @@ func (ep *ExtraProfile) With(key string, value any) *ExtraProfile {
 	return ep
 }
 
-func canonicalizeIfObject(data json.RawMessage) json.RawMessage {
-	if len(data) > 0 && (data[0] == '{' || data[0] == '[') {
-		return canonicaljson.CanonicalJSONAssumeValid(data)
-	}
-	return data
+func canonicalize(data json.RawMessage) json.RawMessage {
+	canonicalized, _ := canonicaljson.Marshal(data)
+	return canonicalized
 }
 
 func (ep *ExtraProfile) CopyTo(dest *ExtraProfile) (changed bool) {
@@ -68,7 +66,7 @@ func (ep *ExtraProfile) CopyTo(dest *ExtraProfile) (changed bool) {
 			continue
 		}
 		existing, exists := (*dest)[key]
-		if !exists || !bytes.Equal(canonicalizeIfObject(existing), val) {
+		if !exists || !bytes.Equal(canonicalize(existing), val) {
 			(*dest)[key] = val
 			changed = true
 		}
diff --git a/bridgev2/matrix/intent.go b/bridgev2/matrix/intent.go
@@ -475,20 +475,16 @@ func dataToFields(data any) (map[string]json.RawMessage, error) {
 	if ok {
 		return fields, nil
 	}
-	d, err := json.Marshal(data)
+	d, err := canonicaljson.Marshal(data)
 	if err != nil {
 		return nil, err
 	}
-	d = canonicaljson.CanonicalJSONAssumeValid(d)
 	err = json.Unmarshal(d, &fields)
 	return fields, err
 }
 
 func marshalField(val any) json.RawMessage {
-	data, _ := json.Marshal(val)
-	if len(data) > 0 && (data[0] == '{' || data[0] == '[') {
-		return canonicaljson.CanonicalJSONAssumeValid(data)
-	}
+	data, _ := canonicaljson.Marshal(val)
 	return data
 }
 
diff --git a/crypto/account.go b/crypto/account.go
@@ -7,7 +7,7 @@
 package crypto
 
 import (
-	"encoding/json"
+	"fmt"
 
 	"github.com/tidwall/sjson"
 
@@ -72,13 +72,18 @@ func (account *OlmAccount) IdentityKey() id.IdentityKey {
 // SignJSON signs the given JSON object following the Matrix specification:
 // https://matrix.org/docs/spec/appendices#signing-json
 func (account *OlmAccount) SignJSON(obj any) (string, error) {
-	objJSON, err := json.Marshal(obj)
+	objJSON, err := canonicaljson.Marshal(obj)
 	if err != nil {
 		return "", err
 	}
 	objJSON, _ = sjson.DeleteBytes(objJSON, "unsigned")
 	objJSON, _ = sjson.DeleteBytes(objJSON, "signatures")
-	signed, err := account.Internal.Sign(canonicaljson.CanonicalJSONAssumeValid(objJSON))
+	// This is probably not necessary
+	err = canonicaljson.Canonicalize(&objJSON)
+	if err != nil {
+		return "", fmt.Errorf("failed to canonicalize JSON after deleting unsigned and signatures: %w", err)
+	}
+	signed, err := account.Internal.Sign(objJSON)
 	return string(signed), err
 }
 
diff --git a/crypto/canonicaljson/json.go b/crypto/canonicaljson/json.go
@@ -1,3 +1,5 @@
+//go:build !goexperiment.jsonv2
+
 /* Copyright 2016-2017 Vector Creations Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -17,16 +19,32 @@ package canonicaljson
 
 import (
 	"encoding/binary"
+	"encoding/json"
 	"fmt"
 	"sort"
 	"unicode/utf8"
 
 	"github.com/tidwall/gjson"
 )
 
+func Canonicalize(input *json.RawMessage) error {
+	*input = CanonicalJSONAssumeValid(*input)
+	return nil
+}
+
+func Marshal(v any) (json.RawMessage, error) {
+	marshaled, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	return CanonicalJSONAssumeValid(marshaled), nil
+}
+
 // CanonicalJSON re-encodes the JSON in a canonical encoding. The encoding is
 // the shortest possible encoding using integer values with sorted object keys.
 // https://matrix.org/docs/spec/appendices#canonical-json
+//
+// Deprecated: Use the new Canonicalize or Marshal functions which will transparently migrate to jsonv2
 func CanonicalJSON(input []byte) ([]byte, error) {
 	if !gjson.Valid(string(input)) {
 		return nil, fmt.Errorf("invalid json")
@@ -37,13 +55,17 @@ func CanonicalJSON(input []byte) ([]byte, error) {
 
 // CanonicalJSONAssumeValid is the same as CanonicalJSON, but assumes the
 // input is valid JSON
+//
+// Deprecated: Use the new Canonicalize or Marshal functions which will transparently migrate to jsonv2
 func CanonicalJSONAssumeValid(input []byte) []byte {
 	input = CompactJSON(input, make([]byte, 0, len(input)))
 	return SortJSON(input, make([]byte, 0, len(input)))
 }
 
 // SortJSON reencodes the JSON with the object keys sorted by lexicographically
 // by codepoint. The input must be valid JSON.
+//
+// Deprecated: Use the new Canonicalize or Marshal functions which will transparently migrate to jsonv2
 func SortJSON(input, output []byte) []byte {
 	result := gjson.ParseBytes(input)
 
@@ -141,6 +163,8 @@ func sortJSONObject(input gjson.Result, inputJSON, output []byte) []byte {
 
 // CompactJSON makes the encoded JSON as small as possible by removing
 // whitespace and unneeded unicode escapes
+//
+// Deprecated: Use the new Canonicalize or Marshal functions which will transparently migrate to jsonv2
 func CompactJSON(input, output []byte) []byte {
 	var i int
 	for i < len(input) {
diff --git a/crypto/canonicaljson/json_test.go b/crypto/canonicaljson/json_test.go
@@ -1,3 +1,5 @@
+//go:build !goexperiment.jsonv2
+
 /* Copyright 2016-2017 Vector Creations Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/crypto/canonicaljson/jsonv2.go b/crypto/canonicaljson/jsonv2.go
@@ -229,3 +229,16 @@ func reorderObjectsAndValidate(d *jsontext.Decoder, buf []byte, scratch *[]byte)
 		return cmp.Or(err, fmt.Errorf("unexpected token: %s", tok))
 	}
 }
+
+// Deprecated: Use the new Canonicalize or Marshal functions
+func CanonicalJSONAssumeValid(input []byte) []byte {
+	out, _ := CanonicalJSON(input)
+	return out
+}
+
+// Deprecated: Use the new Canonicalize or Marshal functions
+func CanonicalJSON(input []byte) ([]byte, error) {
+	out := jsontext.Value(bytes.Clone(input))
+	err := Canonicalize(&out)
+	return out, err
+}
diff --git a/crypto/goolm/pk/signing.go b/crypto/goolm/pk/signing.go
@@ -2,7 +2,7 @@ package pk
 
 import (
 	"crypto/rand"
-	"encoding/json"
+	"fmt"
 
 	"github.com/tidwall/sjson"
 
@@ -55,12 +55,17 @@ func (s Signing) Sign(message []byte) ([]byte, error) {
 // SignJSON creates a signature for the given object after encoding it to
 // canonical JSON.
 func (s Signing) SignJSON(obj any) (string, error) {
-	objJSON, err := json.Marshal(obj)
+	objJSON, err := canonicaljson.Marshal(obj)
 	if err != nil {
 		return "", err
 	}
 	objJSON, _ = sjson.DeleteBytes(objJSON, "unsigned")
 	objJSON, _ = sjson.DeleteBytes(objJSON, "signatures")
-	signature, err := s.Sign(canonicaljson.CanonicalJSONAssumeValid(objJSON))
+	// This is probably not necessary
+	err = canonicaljson.Canonicalize(&objJSON)
+	if err != nil {
+		return "", fmt.Errorf("failed to canonicalize JSON after deleting unsigned and signatures: %w", err)
+	}
+	signature, err := s.Sign(objJSON)
 	return string(signature), err
 }
diff --git a/crypto/libolm/pk.go b/crypto/libolm/pk.go
@@ -13,7 +13,7 @@ import "C"
 
 import (
 	"crypto/rand"
-	"encoding/json"
+	"fmt"
 	"runtime"
 	"unsafe"
 
@@ -124,13 +124,18 @@ func (p *PKSigning) Sign(message []byte) ([]byte, error) {
 
 // SignJSON creates a signature for the given object after encoding it to canonical JSON.
 func (p *PKSigning) SignJSON(obj interface{}) (string, error) {
-	objJSON, err := json.Marshal(obj)
+	objJSON, err := canonicaljson.Marshal(obj)
 	if err != nil {
 		return "", err
 	}
 	objJSON, _ = sjson.DeleteBytes(objJSON, "unsigned")
 	objJSON, _ = sjson.DeleteBytes(objJSON, "signatures")
-	signature, err := p.Sign(canonicaljson.CanonicalJSONAssumeValid(objJSON))
+	// This is probably not necessary
+	err = canonicaljson.Canonicalize(&objJSON)
+	if err != nil {
+		return "", fmt.Errorf("failed to canonicalize JSON after deleting unsigned and signatures: %w", err)
+	}
+	signature, err := p.Sign(objJSON)
 	if err != nil {
 		return "", err
 	}
diff --git a/crypto/signatures/signatures.go b/crypto/signatures/signatures.go
@@ -7,6 +7,7 @@
 package signatures
 
 import (
+	"bytes"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
@@ -67,10 +68,13 @@ func VerifySignatureJSON(obj any, userID id.UserID, keyName string, key id.Ed255
 	var err error
 	objJSON, ok := obj.(json.RawMessage)
 	if !ok {
-		objJSON, err = json.Marshal(obj)
+		objJSON, err = canonicaljson.Marshal(obj)
 		if err != nil {
 			return false, err
 		}
+	} else {
+		// Canonicalize later may mutate the data, so clone the input
+		objJSON = bytes.Clone(objJSON)
 	}
 
 	sig := gjson.GetBytes(objJSON, exgjson.Path("signatures", string(userID), fmt.Sprintf("ed25519:%s", keyName)))
@@ -85,10 +89,13 @@ func VerifySignatureJSON(obj any, userID id.UserID, keyName string, key id.Ed255
 	if err != nil {
 		return false, err
 	}
-	objJSONString := canonicaljson.CanonicalJSONAssumeValid(objJSON)
+	err = canonicaljson.Canonicalize(&objJSON)
+	if err != nil {
+		return false, fmt.Errorf("failed to canonicalize JSON after deleting unsigned and signatures: %w", err)
+	}
 	sigBytes, err := base64.RawStdEncoding.DecodeString(sig.Str)
 	if err != nil {
 		return false, err
 	}
-	return VerifySignature(objJSONString, key, sigBytes)
+	return VerifySignature(objJSON, key, sigBytes)
 }
diff --git a/crypto/verificationhelper/sas.go b/crypto/verificationhelper/sas.go
@@ -15,7 +15,6 @@ import (
 	"crypto/sha256"
 	"crypto/subtle"
 	"encoding/base64"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"strings"
@@ -259,11 +258,11 @@ func calculateCommitment(ephemeralPubKey *ecdh.PublicKey, txn VerificationTransa
 	// hashing it, but we are just stuck on that.
 	commitmentHashInput := sha256.New()
 	commitmentHashInput.Write([]byte(base64.RawStdEncoding.EncodeToString(ephemeralPubKey.Bytes())))
-	encodedStartEvt, err := json.Marshal(txn.StartEventContent)
+	encodedStartEvt, err := canonicaljson.Marshal(txn.StartEventContent)
 	if err != nil {
 		return nil, err
 	}
-	commitmentHashInput.Write(canonicaljson.CanonicalJSONAssumeValid(encodedStartEvt))
+	commitmentHashInput.Write(encodedStartEvt)
 	return commitmentHashInput.Sum(nil), nil
 }
 
diff --git a/federation/client.go b/federation/client.go
@@ -23,6 +23,7 @@ import (
 	"go.mau.fi/util/jsontime"
 
 	"maunium.net/go/mautrix"
+	"maunium.net/go/mautrix/crypto/canonicaljson"
 	"maunium.net/go/mautrix/federation/signutil"
 	"maunium.net/go/mautrix/id"
 )
@@ -607,11 +608,11 @@ type signableRequest struct {
 }
 
 func (r *signableRequest) Verify(key id.SigningKey, sig string) error {
-	message, err := json.Marshal(r)
+	message, err := canonicaljson.Marshal(r)
 	if err != nil {
 		return fmt.Errorf("failed to marshal data: %w", err)
 	}
-	return signutil.VerifyJSONRaw(key, sig, message)
+	return signutil.VerifyJSONCanonical(key, sig, message)
 }
 
 func (r *signableRequest) Sign(key *SigningKey) (string, error) {
diff --git a/federation/pdu/signature.go b/federation/pdu/signature.go
@@ -54,7 +54,7 @@ func (pdu *PDU) VerifySignature(roomVersion id.RoomVersion, serverName string, g
 			errorList = append(errorList, fmt.Errorf("key %s not found for %s", keyID, serverName))
 		} else if validUntil.Before(originServerTS) && roomVersion.EnforceSigningKeyValidity() {
 			errorList = append(errorList, fmt.Errorf("key %s for %s is only valid until %s, but event is from %s", keyID, serverName, validUntil, originServerTS))
-		} else if err = signutil.VerifyJSONRaw(key, sig, rawJSON); err != nil {
+		} else if err = signutil.VerifyJSONCanonical(key, sig, rawJSON); err != nil {
 			return fmt.Errorf("failed to verify signature from key %s: %w", keyID, err)
 		} else {
 			verified = true
diff --git a/federation/pdu/v1.go b/federation/pdu/v1.go
@@ -208,7 +208,7 @@ func (pdu *RoomV1PDU) VerifySignature(roomVersion id.RoomVersion, serverName str
 			return fmt.Errorf("failed to get key %s for %s: %w", keyID, serverName, err)
 		} else if key == "" {
 			return fmt.Errorf("key %s not found for %s", keyID, serverName)
-		} else if err = signutil.VerifyJSONRaw(key, sig, rawJSON); err != nil {
+		} else if err = signutil.VerifyJSONCanonical(key, sig, rawJSON); err != nil {
 			return fmt.Errorf("failed to verify signature from key %s: %w", keyID, err)
 		} else {
 			verified = true
diff --git a/federation/signingkey.go b/federation/signingkey.go
@@ -126,19 +126,23 @@ type OldVerifyKey struct {
 }
 
 func (sk *SigningKey) SignJSON(data any) (string, error) {
-	marshaled, err := json.Marshal(data)
+	marshaled, err := canonicaljson.Marshal(data)
 	if err != nil {
 		return "", err
 	}
 	marshaled, err = sjson.DeleteBytes(marshaled, "signatures")
 	if err != nil {
 		return "", err
 	}
-	return base64.RawStdEncoding.EncodeToString(sk.SignRawJSON(marshaled)), nil
+	err = canonicaljson.Canonicalize(&marshaled)
+	if err != nil {
+		return "", fmt.Errorf("failed to canonicalize JSON after deleting signatures: %w", err)
+	}
+	return base64.RawStdEncoding.EncodeToString(sk.SignCanonicalJSON(marshaled)), err
 }
 
-func (sk *SigningKey) SignRawJSON(data json.RawMessage) []byte {
-	return ed25519.Sign(sk.Priv, canonicaljson.CanonicalJSONAssumeValid(data))
+func (sk *SigningKey) SignCanonicalJSON(data json.RawMessage) []byte {
+	return ed25519.Sign(sk.Priv, data)
 }
 
 // GenerateKeyResponse generates a key response signed by this key with the given server name and optionally some old verify keys.
diff --git a/federation/signutil/verify.go b/federation/signutil/verify.go
diff --git a/responses_test.go b/responses_test.go

Original file line number	Diff line number	Diff line change
`@@ -33,14 +33,14 @@ func (ep *ExtraProfile) Set(key string, value any) error {`
`33`	`33`	`if key == "displayname" \|\| key == "avatar_url" {`
`34`	`34`	`return fmt.Errorf("cannot set reserved profile key %q", key)`
`35`	`35`	`}`
`36`		`- marshaled, err := json.Marshal(value)`
	`36`	`+ marshaled, err := canonicaljson.Marshal(value)`
`37`	`37`	`if err != nil {`
`38`	`38`	`return err`
`39`	`39`	`}`
`40`	`40`	`if *ep == nil {`
`41`	`41`	`*ep = make(ExtraProfile)`
`42`	`42`	`}`
`43`		`- (*ep)[key] = canonicaljson.CanonicalJSONAssumeValid(marshaled)`
	`43`	`+ (*ep)[key] = marshaled`
`44`	`44`	`return nil`
`45`	`45`	`}`
`46`	`46`
`@@ -49,11 +49,9 @@ func (ep ExtraProfile) With(key string, value any) ExtraProfile {`
`49`	`49`	`return ep`
`50`	`50`	`}`
`51`	`51`
`52`		`-func canonicalizeIfObject(data json.RawMessage) json.RawMessage {`
`53`		`- if len(data) > 0 && (data[0] == '{' \|\| data[0] == '[') {`
`54`		`- return canonicaljson.CanonicalJSONAssumeValid(data)`
`55`		`- }`
`56`		`- return data`
	`52`	`+func canonicalize(data json.RawMessage) json.RawMessage {`
	`53`	`+ canonicalized, _ := canonicaljson.Marshal(data)`
	`54`	`+ return canonicalized`
`57`	`55`	`}`
`58`	`56`
`59`	`57`	`func (ep ExtraProfile) CopyTo(dest ExtraProfile) (changed bool) {`
`@@ -68,7 +66,7 @@ func (ep ExtraProfile) CopyTo(dest ExtraProfile) (changed bool) {`
`68`	`66`	`continue`
`69`	`67`	`}`
`70`	`68`	`existing, exists := (*dest)[key]`
`71`		`- if !exists \|\| !bytes.Equal(canonicalizeIfObject(existing), val) {`
	`69`	`+ if !exists \|\| !bytes.Equal(canonicalize(existing), val) {`
`72`	`70`	`(*dest)[key] = val`
`73`	`71`	`changed = true`
`74`	`72`	`}`
Original file line number	Diff line number	Diff line change
`@@ -475,20 +475,16 @@ func dataToFields(data any) (map[string]json.RawMessage, error) {`
`475`	`475`	`if ok {`
`476`	`476`	`return fields, nil`
`477`	`477`	`}`
`478`		`- d, err := json.Marshal(data)`
	`478`	`+ d, err := canonicaljson.Marshal(data)`
`479`	`479`	`if err != nil {`
`480`	`480`	`return nil, err`
`481`	`481`	`}`
`482`		`- d = canonicaljson.CanonicalJSONAssumeValid(d)`
`483`	`482`	`err = json.Unmarshal(d, &fields)`
`484`	`483`	`return fields, err`
`485`	`484`	`}`
`486`	`485`
`487`	`486`	`func marshalField(val any) json.RawMessage {`
`488`		`- data, _ := json.Marshal(val)`
`489`		`- if len(data) > 0 && (data[0] == '{' \|\| data[0] == '[') {`
`490`		`- return canonicaljson.CanonicalJSONAssumeValid(data)`
`491`		`- }`
	`487`	`+ data, _ := canonicaljson.Marshal(val)`
`492`	`488`	`return data`
`493`	`489`	`}`
`494`	`490`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+//go:build !goexperiment.jsonv2`
	`2`	`+`
`1`	`3`	`/* Copyright 2016-2017 Vector Creations Ltd`
`2`	`4`	`*`
`3`	`5`	`* Licensed under the Apache License, Version 2.0 (the "License");`