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author | Viktor TrĂ³n <viktor.tron@gmail.com> | 2018-10-03 20:59:41 +0800 |
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committer | GitHub <noreply@github.com> | 2018-10-03 20:59:41 +0800 |
commit | e5677114dc7461fe39ebe353a4657aa4cb03fde4 (patch) | |
tree | 8605f9a8b726b158fd01b4befced1e3ba92ca1f9 /swarm/storage/feed/request.go | |
parent | 303b99663e963a520aaa44eca68e042d9fe230af (diff) | |
parent | de01178c18766b9f744acc94fe2b96804f998e40 (diff) | |
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Merge pull request #17796 from epiclabs-io/mru-feeds
swarm/storage/feeds: Renamed MRU to Swarm Feeds
Diffstat (limited to 'swarm/storage/feed/request.go')
-rw-r--r-- | swarm/storage/feed/request.go | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/swarm/storage/feed/request.go b/swarm/storage/feed/request.go new file mode 100644 index 000000000..6968d8b9a --- /dev/null +++ b/swarm/storage/feed/request.go @@ -0,0 +1,284 @@ +// Copyright 2018 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. + +package feed + +import ( + "bytes" + "encoding/json" + "hash" + + "github.com/ethereum/go-ethereum/common" + "github.com/ethereum/go-ethereum/common/hexutil" + "github.com/ethereum/go-ethereum/swarm/storage" + "github.com/ethereum/go-ethereum/swarm/storage/feed/lookup" +) + +// Request represents a request to sign or signed feed update message +type Request struct { + Update // actual content that will be put on the chunk, less signature + Signature *Signature + idAddr storage.Address // cached chunk address for the update (not serialized, for internal use) + binaryData []byte // cached serialized data (does not get serialized again!, for efficiency/internal use) +} + +// updateRequestJSON represents a JSON-serialized UpdateRequest +type updateRequestJSON struct { + ID + ProtocolVersion uint8 `json:"protocolVersion"` + Data string `json:"data,omitempty"` + Signature string `json:"signature,omitempty"` +} + +// Request layout +// Update bytes +// SignatureLength bytes +const minimumSignedUpdateLength = minimumUpdateDataLength + signatureLength + +// NewFirstRequest returns a ready to sign request to publish a first feed update +func NewFirstRequest(topic Topic) *Request { + + request := new(Request) + + // get the current time + now := TimestampProvider.Now().Time + request.Epoch = lookup.GetFirstEpoch(now) + request.Feed.Topic = topic + request.Header.Version = ProtocolVersion + + return request +} + +// SetData stores the payload data the feed update will be updated with +func (r *Request) SetData(data []byte) { + r.data = data + r.Signature = nil +} + +// IsUpdate returns true if this request models a signed update or otherwise it is a signature request +func (r *Request) IsUpdate() bool { + return r.Signature != nil +} + +// Verify checks that signatures are valid +func (r *Request) Verify() (err error) { + if len(r.data) == 0 { + return NewError(ErrInvalidValue, "Update does not contain data") + } + if r.Signature == nil { + return NewError(ErrInvalidSignature, "Missing signature field") + } + + digest, err := r.GetDigest() + if err != nil { + return err + } + + // get the address of the signer (which also checks that it's a valid signature) + r.Feed.User, err = getUserAddr(digest, *r.Signature) + if err != nil { + return err + } + + // check that the lookup information contained in the chunk matches the updateAddr (chunk search key) + // that was used to retrieve this chunk + // if this validation fails, someone forged a chunk. + if !bytes.Equal(r.idAddr, r.Addr()) { + return NewError(ErrInvalidSignature, "Signature address does not match with update user address") + } + + return nil +} + +// Sign executes the signature to validate the update message +func (r *Request) Sign(signer Signer) error { + r.Feed.User = signer.Address() + r.binaryData = nil //invalidate serialized data + digest, err := r.GetDigest() // computes digest and serializes into .binaryData + if err != nil { + return err + } + + signature, err := signer.Sign(digest) + if err != nil { + return err + } + + // Although the Signer interface returns the public address of the signer, + // recover it from the signature to see if they match + userAddr, err := getUserAddr(digest, signature) + if err != nil { + return NewError(ErrInvalidSignature, "Error verifying signature") + } + + if userAddr != signer.Address() { // sanity check to make sure the Signer is declaring the same address used to sign! + return NewError(ErrInvalidSignature, "Signer address does not match update user address") + } + + r.Signature = &signature + r.idAddr = r.Addr() + return nil +} + +// GetDigest creates the feed update digest used in signatures +// the serialized payload is cached in .binaryData +func (r *Request) GetDigest() (result common.Hash, err error) { + hasher := hashPool.Get().(hash.Hash) + defer hashPool.Put(hasher) + hasher.Reset() + dataLength := r.Update.binaryLength() + if r.binaryData == nil { + r.binaryData = make([]byte, dataLength+signatureLength) + if err := r.Update.binaryPut(r.binaryData[:dataLength]); err != nil { + return result, err + } + } + hasher.Write(r.binaryData[:dataLength]) //everything except the signature. + + return common.BytesToHash(hasher.Sum(nil)), nil +} + +// create an update chunk. +func (r *Request) toChunk() (storage.Chunk, error) { + + // Check that the update is signed and serialized + // For efficiency, data is serialized during signature and cached in + // the binaryData field when computing the signature digest in .getDigest() + if r.Signature == nil || r.binaryData == nil { + return nil, NewError(ErrInvalidSignature, "toChunk called without a valid signature or payload data. Call .Sign() first.") + } + + updateLength := r.Update.binaryLength() + + // signature is the last item in the chunk data + copy(r.binaryData[updateLength:], r.Signature[:]) + + chunk := storage.NewChunk(r.idAddr, r.binaryData) + return chunk, nil +} + +// fromChunk populates this structure from chunk data. It does not verify the signature is valid. +func (r *Request) fromChunk(updateAddr storage.Address, chunkdata []byte) error { + // for update chunk layout see Request definition + + //deserialize the feed update portion + if err := r.Update.binaryGet(chunkdata[:len(chunkdata)-signatureLength]); err != nil { + return err + } + + // Extract the signature + var signature *Signature + cursor := r.Update.binaryLength() + sigdata := chunkdata[cursor : cursor+signatureLength] + if len(sigdata) > 0 { + signature = &Signature{} + copy(signature[:], sigdata) + } + + r.Signature = signature + r.idAddr = updateAddr + r.binaryData = chunkdata + + return nil + +} + +// FromValues deserializes this instance from a string key-value store +// useful to parse query strings +func (r *Request) FromValues(values Values, data []byte) error { + signatureBytes, err := hexutil.Decode(values.Get("signature")) + if err != nil { + r.Signature = nil + } else { + if len(signatureBytes) != signatureLength { + return NewError(ErrInvalidSignature, "Incorrect signature length") + } + r.Signature = new(Signature) + copy(r.Signature[:], signatureBytes) + } + err = r.Update.FromValues(values, data) + if err != nil { + return err + } + r.idAddr = r.Addr() + return err +} + +// AppendValues serializes this structure into the provided string key-value store +// useful to build query strings +func (r *Request) AppendValues(values Values) []byte { + if r.Signature != nil { + values.Set("signature", hexutil.Encode(r.Signature[:])) + } + return r.Update.AppendValues(values) +} + +// fromJSON takes an update request JSON and populates an UpdateRequest +func (r *Request) fromJSON(j *updateRequestJSON) error { + + r.ID = j.ID + r.Header.Version = j.ProtocolVersion + + var err error + if j.Data != "" { + r.data, err = hexutil.Decode(j.Data) + if err != nil { + return NewError(ErrInvalidValue, "Cannot decode data") + } + } + + if j.Signature != "" { + sigBytes, err := hexutil.Decode(j.Signature) + if err != nil || len(sigBytes) != signatureLength { + return NewError(ErrInvalidSignature, "Cannot decode signature") + } + r.Signature = new(Signature) + r.idAddr = r.Addr() + copy(r.Signature[:], sigBytes) + } + return nil +} + +// UnmarshalJSON takes a JSON structure stored in a byte array and populates the Request object +// Implements json.Unmarshaler interface +func (r *Request) UnmarshalJSON(rawData []byte) error { + var requestJSON updateRequestJSON + if err := json.Unmarshal(rawData, &requestJSON); err != nil { + return err + } + return r.fromJSON(&requestJSON) +} + +// MarshalJSON takes an update request and encodes it as a JSON structure into a byte array +// Implements json.Marshaler interface +func (r *Request) MarshalJSON() (rawData []byte, err error) { + var signatureString, dataString string + if r.Signature != nil { + signatureString = hexutil.Encode(r.Signature[:]) + } + if r.data != nil { + dataString = hexutil.Encode(r.data) + } + + requestJSON := &updateRequestJSON{ + ID: r.ID, + ProtocolVersion: r.Header.Version, + Data: dataString, + Signature: signatureString, + } + + return json.Marshal(requestJSON) +} |