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package stfe
import (
"fmt"
"strconv"
"encoding/base64"
"encoding/json"
"io/ioutil"
"net/http"
"github.com/google/certificate-transparency-go/tls"
"github.com/google/certificate-transparency-go/trillian/ctfe"
"github.com/google/trillian"
)
// AddEntryRequest is a collection of add-entry input parameters
type AddEntryRequest struct {
Item string `json:"item"` // base64-encoded StItem
Signature string `json:"signature"` // base64-encoded DigitallySigned
Certificate string `json:"certificate"` // base64-encoded X.509 certificate
}
// GetEntriesRequest is a collection of get-entry input parameters
type GetEntriesRequest struct {
Start int64 `json:"start"` // 0-based and inclusive start-index
End int64 `json:"end"` // 0-based and inclusive end-index
}
// GetProofByHashRequest is a collection of get-proof-by-hash input parameters
type GetProofByHashRequest struct {
Hash []byte `json:"hash"` // base64-encoded leaf hash
TreeSize int64 `json:"tree_size"` // Tree head size to base proof on
}
// GetEntryResponse is an assembled log entry and its associated appendix
type GetEntryResponse struct {
Leaf string `json:"leaf"` // base64-encoded StItem
Signature string `json:"signature"` // base64-encoded DigitallySigned
Chain []string `json:"chain"` // base64-encoded X.509 certificates
}
// GetEntriesResponse is an assembled get-entries responses
type GetEntriesResponse struct {
Entries []GetEntryResponse `json:"entries"`
}
// GetProofByHashResponse is an assembled inclusion proof response
type GetProofByHashResponse struct {
InclusionProof string `json:"inclusion_proof"` // base64-encoded StItem
}
// NewAddEntryRequest parses and sanitizes the JSON-encoded add-entry
// parameters from an incoming HTTP post. The resulting AddEntryRequest is
// well-formed, but not necessarily trusted (further sanitization is needed).
func NewAddEntryRequest(r *http.Request) (AddEntryRequest, error) {
var ret AddEntryRequest
if err := UnpackJsonPost(r, &ret); err != nil {
return ret, err
}
item, err := StItemFromB64(ret.Item)
if err != nil {
return ret, fmt.Errorf("failed decoding StItem: %v", err)
}
if item.Format != StFormatChecksumV1 {
return ret, fmt.Errorf("invalid StItem format: %s", item.Format)
}
// TODO: verify that we got a checksum length
// TODO: verify that we got a signature and certificate
return ret, nil
}
// NewGetEntriesRequest parses and sanitizes the URL-encoded get-entries
// parameters from an incoming HTTP request.
func NewGetEntriesRequest(httpRequest *http.Request) (GetEntriesRequest, error) {
start, err := strconv.ParseInt(httpRequest.FormValue("start"), 10, 64)
if err != nil {
return GetEntriesRequest{}, fmt.Errorf("bad start parameter: %v", err)
}
end, err := strconv.ParseInt(httpRequest.FormValue("end"), 10, 64)
if err != nil {
return GetEntriesRequest{}, fmt.Errorf("bad end parameter: %v", err)
}
if start < 0 {
return GetEntriesRequest{}, fmt.Errorf("bad parameters: start(%v) must have a non-negative value", start)
}
if start > end {
return GetEntriesRequest{}, fmt.Errorf("bad parameters: start(%v) must be larger than end(%v)", start, end)
}
// TODO: check that range is not larger than the max range. Yes -> truncate
// TODO: check that end is not past the most recent STH. Yes -> truncate
return GetEntriesRequest{Start: start, End: end}, nil
}
// NewGetProofByHashRequest parses and sanitizes the URL-encoded
// get-proof-by-hash parameters from an incoming HTTP request.
func NewGetProofByHashRequest(httpRequest *http.Request) (GetProofByHashRequest, error) {
treeSize, err := strconv.ParseInt(httpRequest.FormValue("tree_size"), 10, 64)
if err != nil {
return GetProofByHashRequest{}, fmt.Errorf("bad tree_size parameter: %v", err)
}
if treeSize < 0 {
return GetProofByHashRequest{}, fmt.Errorf("bad tree_size parameter: negative value")
}
// TODO: check that tree size is not past STH.tree_size
hash, err := base64.StdEncoding.DecodeString(httpRequest.FormValue("hash"))
if err != nil {
return GetProofByHashRequest{}, fmt.Errorf("bad hash parameter: %v", err)
}
return GetProofByHashRequest{TreeSize: treeSize, Hash: hash}, nil
}
// NewGetEntryResponse assembles a log entry and its appendix
func NewGetEntryResponse(leaf []byte) GetEntryResponse {
return GetEntryResponse{
Leaf: base64.StdEncoding.EncodeToString(leaf),
// TODO: add signature and chain
}
}
// NewGetEntriesResponse assembles a get-entries response
func NewGetEntriesResponse(leaves []*trillian.LogLeaf) (GetEntriesResponse, error) {
entries := make([]GetEntryResponse, 0, len(leaves))
for _, leaf := range leaves {
entries = append(entries, NewGetEntryResponse(leaf.GetLeafValue())) // TODO: add signature and chain
}
return GetEntriesResponse{entries}, nil
}
// NewGetProofByHashResponse assembles a get-proof-by-hash response
func NewGetProofByHashResponse(treeSize uint64, inclusionProof *trillian.Proof) (*GetProofByHashResponse, error) {
item := NewInclusionProofV1([]byte("TODO: add log ID"), treeSize, inclusionProof)
b, err := tls.Marshal(item)
if err != nil {
return nil, fmt.Errorf("tls marshal failed: %v", err)
}
return &GetProofByHashResponse{
InclusionProof: base64.StdEncoding.EncodeToString(b),
}, nil
}
// VerifyAddEntryRequest determines whether a well-formed AddEntryRequest should
// be inserted into the log. If so, the serialized leaf value is returned.
func VerifyAddEntryRequest(a ctfe.CertValidationOpts, r AddEntryRequest) ([]byte, error) {
item, _ := StItemFromB64(r.Item) // r.Item is a well-formed ChecksumV1
leaf, _ := tls.Marshal(item) // again, r.Item is well-formed
chainBytes, err := base64.StdEncoding.DecodeString(r.Certificate)
if err != nil {
return nil, fmt.Errorf("failed decoding certificate: %v", err)
}
chain := make([][]byte, 0, 1)
chain = append(chain, chainBytes)
_, err = ctfe.ValidateChain(chain, a)
if err != nil {
return nil, fmt.Errorf("chain verification failed: %v", err)
}
// TODO: verify signature
return leaf, nil
}
// UnpackJsonPost unpacks a json-encoded HTTP POST request into `unpack`
func UnpackJsonPost(r *http.Request, unpack interface{}) error {
body, err := ioutil.ReadAll(r.Body)
if err != nil {
return fmt.Errorf("failed reading request body: %v", err)
}
if err := json.Unmarshal(body, &unpack); err != nil {
return fmt.Errorf("failed parsing json body: %v", err)
}
return nil
}
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