frostfs-api-go/service/sign.go

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package service
import (
"crypto/ecdsa"
"sync"
crypto "github.com/nspcc-dev/neofs-crypto"
)
type keySign struct {
key *ecdsa.PublicKey
sign []byte
}
var bytesPool = sync.Pool{
New: func() interface{} {
return make([]byte, 5<<20)
},
}
// GetSignature is a sign field getter.
func (s keySign) GetSignature() []byte {
return s.sign
}
// GetPublicKey is a key field getter,
func (s keySign) GetPublicKey() *ecdsa.PublicKey {
return s.key
}
// Unites passed key with signature and returns SignKeyPair interface.
func newSignatureKeyPair(key *ecdsa.PublicKey, sign []byte) SignKeyPair {
return &keySign{
key: key,
sign: sign,
}
}
// Returns data from DataSignatureAccumulator for signature creation/verification.
//
// If passed DataSignatureAccumulator provides a SignedDataReader interface, data for signature is obtained
// using this interface for optimization. In this case, it is understood that reading into the slice D
// that the method DataForSignature returns does not change D.
//
// If returned length of data is negative, ErrNegativeLength returns.
func dataForSignature(src SignedDataSource) ([]byte, error) {
if src == nil {
return nil, ErrNilSignedDataSource
}
r, ok := src.(SignedDataReader)
if !ok {
return src.SignedData()
}
buf := bytesPool.Get().([]byte)
if size := r.SignedDataSize(); size < 0 {
return nil, ErrNegativeLength
} else if size <= cap(buf) {
buf = buf[:size]
} else {
buf = make([]byte, size)
}
n, err := r.ReadSignedData(buf)
if err != nil {
return nil, err
}
return buf[:n], nil
}
// DataSignature returns the signature of data obtained using the private key.
//
// If passed data container is nil, ErrNilSignedDataSource returns.
// If passed private key is nil, crypto.ErrEmptyPrivateKey returns.
// If the data container or the signature function returns an error, it is returned directly.
func DataSignature(key *ecdsa.PrivateKey, src SignedDataSource) ([]byte, error) {
if key == nil {
return nil, crypto.ErrEmptyPrivateKey
}
data, err := dataForSignature(src)
if err != nil {
return nil, err
}
defer bytesPool.Put(data)
return crypto.Sign(key, data)
}
// AddSignatureWithKey calculates the data signature and adds it to accumulator with public key.
//
// Any change of data provoke signature breakdown.
//
// Returns signing errors only.
func AddSignatureWithKey(key *ecdsa.PrivateKey, v DataWithSignKeyAccumulator) error {
sign, err := DataSignature(key, v)
if err != nil {
return err
}
v.AddSignKey(sign, &key.PublicKey)
return nil
}
// Checks passed key-signature pairs for data from the passed container.
//
// If passed key-signatures pair set is empty, nil returns immediately.
func verifySignatures(src SignedDataSource, items ...SignKeyPair) error {
if len(items) <= 0 {
return nil
}
data, err := dataForSignature(src)
if err != nil {
return err
}
defer bytesPool.Put(data)
for _, signKey := range items {
if err := crypto.Verify(
signKey.GetPublicKey(),
data,
signKey.GetSignature(),
); err != nil {
return err
}
}
return nil
}
// VerifySignatures checks passed key-signature pairs for data from the passed container.
//
// If passed data source is nil, ErrNilSignedDataSource returns.
// If check data is not ready, corresponding error returns.
// If at least one of the pairs is invalid, an error returns.
func VerifySignatures(src SignedDataSource, items ...SignKeyPair) error {
return verifySignatures(src, items...)
}
// VerifyAccumulatedSignatures checks if accumulated key-signature pairs are valid.
//
// Behaves like VerifySignatures.
// If passed key-signature source is empty, ErrNilSignatureKeySource returns.
func VerifyAccumulatedSignatures(src DataWithSignKeySource) error {
if src == nil {
return ErrNilSignatureKeySource
}
return verifySignatures(src, src.GetSignKeyPairs()...)
}
// VerifySignatureWithKey checks data signature from the passed container with passed key.
//
// If passed data with signature is nil, ErrEmptyDataWithSignature returns.
// If passed key is nil, crypto.ErrEmptyPublicKey returns.
// A non-nil error returns if and only if the signature does not pass verification.
func VerifySignatureWithKey(key *ecdsa.PublicKey, src DataWithSignature) error {
if src == nil {
return ErrEmptyDataWithSignature
} else if key == nil {
return crypto.ErrEmptyPublicKey
}
return verifySignatures(
src,
newSignatureKeyPair(
key,
src.GetSignature(),
),
)
}
// SignDataWithSessionToken calculates data with token signature and adds it to accumulator.
//
// Any change of data or session token info provoke signature breakdown.
//
// If passed private key is nil, crypto.ErrEmptyPrivateKey returns.
// If passed DataWithTokenSignAccumulator is nil, ErrNilDataWithTokenSignAccumulator returns.
func SignDataWithSessionToken(key *ecdsa.PrivateKey, src DataWithTokenSignAccumulator) error {
if src == nil {
return ErrNilDataWithTokenSignAccumulator
} else if r, ok := src.(SignedDataReader); ok {
return AddSignatureWithKey(key, &signDataReaderWithToken{
SignedDataSource: src,
SignKeyPairAccumulator: src,
rdr: r,
token: src.GetSessionToken(),
},
)
}
return AddSignatureWithKey(key, &signAccumWithToken{
SignedDataSource: src,
SignKeyPairAccumulator: src,
token: src.GetSessionToken(),
})
}
// VerifyAccumulatedSignaturesWithToken checks if accumulated key-signature pairs of data with token are valid.
//
// If passed DataWithTokenSignSource is nil, ErrNilSignatureKeySourceWithToken returns.
func VerifyAccumulatedSignaturesWithToken(src DataWithTokenSignSource) error {
if src == nil {
return ErrNilSignatureKeySourceWithToken
} else if r, ok := src.(SignedDataReader); ok {
return VerifyAccumulatedSignatures(&signDataReaderWithToken{
SignedDataSource: src,
SignKeyPairSource: src,
rdr: r,
token: src.GetSessionToken(),
})
}
return VerifyAccumulatedSignatures(&signAccumWithToken{
SignedDataSource: src,
SignKeyPairSource: src,
token: src.GetSessionToken(),
})
}