Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
146 lines (125 sloc) 4.41 KB
package proxy
import (
"fmt"
"strings"
"github.com/pkg/errors"
"github.com/tendermint/tendermint/crypto/merkle"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/lite"
lerr "github.com/tendermint/tendermint/lite/errors"
rpcclient "github.com/tendermint/tendermint/rpc/client"
ctypes "github.com/tendermint/tendermint/rpc/core/types"
"github.com/tendermint/tendermint/types"
)
// GetWithProof will query the key on the given node, and verify it has
// a valid proof, as defined by the Verifier.
//
// If there is any error in checking, returns an error.
func GetWithProof(prt *merkle.ProofRuntime, key []byte, reqHeight int64, node rpcclient.Client,
cert lite.Verifier) (
val cmn.HexBytes, height int64, proof *merkle.Proof, err error) {
if reqHeight < 0 {
err = cmn.NewError("Height cannot be negative")
return
}
res, err := GetWithProofOptions(prt, "/key", key,
rpcclient.ABCIQueryOptions{Height: reqHeight, Prove: true},
node, cert)
if err != nil {
return
}
resp := res.Response
val, height = resp.Value, resp.Height
return val, height, proof, err
}
// GetWithProofOptions is useful if you want full access to the ABCIQueryOptions.
// XXX Usage of path? It's not used, and sometimes it's /, sometimes /key, sometimes /store.
func GetWithProofOptions(prt *merkle.ProofRuntime, path string, key []byte, opts rpcclient.ABCIQueryOptions,
node rpcclient.Client, cert lite.Verifier) (
*ctypes.ResultABCIQuery, error) {
opts.Prove = true
res, err := node.ABCIQueryWithOptions(path, key, opts)
if err != nil {
return nil, err
}
resp := res.Response
// Validate the response, e.g. height.
if resp.IsErr() {
err = cmn.NewError("Query error for key %d: %d", key, resp.Code)
return nil, err
}
if len(resp.Key) == 0 || resp.Proof == nil {
return nil, lerr.ErrEmptyTree()
}
if resp.Height == 0 {
return nil, cmn.NewError("Height returned is zero")
}
// AppHash for height H is in header H+1
signedHeader, err := GetCertifiedCommit(resp.Height+1, node, cert)
if err != nil {
return nil, err
}
// Validate the proof against the certified header to ensure data integrity.
if resp.Value != nil {
// Value exists
// XXX How do we encode the key into a string...
storeName, err := parseQueryStorePath(path)
if err != nil {
return nil, err
}
kp := merkle.KeyPath{}
kp = kp.AppendKey([]byte(storeName), merkle.KeyEncodingURL)
kp = kp.AppendKey(resp.Key, merkle.KeyEncodingURL)
err = prt.VerifyValue(resp.Proof, signedHeader.AppHash, kp.String(), resp.Value)
if err != nil {
return nil, errors.Wrap(err, "Couldn't verify value proof")
}
return &ctypes.ResultABCIQuery{Response: resp}, nil
} else {
// Value absent
// Validate the proof against the certified header to ensure data integrity.
// XXX How do we encode the key into a string...
err = prt.VerifyAbsence(resp.Proof, signedHeader.AppHash, string(resp.Key))
if err != nil {
return nil, errors.Wrap(err, "Couldn't verify absence proof")
}
return &ctypes.ResultABCIQuery{Response: resp}, nil
}
}
func parseQueryStorePath(path string) (storeName string, err error) {
if !strings.HasPrefix(path, "/") {
return "", fmt.Errorf("expected path to start with /")
}
paths := strings.SplitN(path[1:], "/", 3)
switch {
case len(paths) != 3:
return "", fmt.Errorf("expected format like /store/<storeName>/key")
case paths[0] != "store":
return "", fmt.Errorf("expected format like /store/<storeName>/key")
case paths[2] != "key":
return "", fmt.Errorf("expected format like /store/<storeName>/key")
}
return paths[1], nil
}
// GetCertifiedCommit gets the signed header for a given height and certifies
// it. Returns error if unable to get a proven header.
func GetCertifiedCommit(h int64, client rpcclient.Client, cert lite.Verifier) (types.SignedHeader, error) {
// FIXME: cannot use cert.GetByHeight for now, as it also requires
// Validators and will fail on querying tendermint for non-current height.
// When this is supported, we should use it instead...
rpcclient.WaitForHeight(client, h, nil)
cresp, err := client.Commit(&h)
if err != nil {
return types.SignedHeader{}, err
}
// Validate downloaded checkpoint with our request and trust store.
sh := cresp.SignedHeader
if sh.Height != h {
return types.SignedHeader{}, fmt.Errorf("height mismatch: want %v got %v",
h, sh.Height)
}
if err = cert.Verify(sh); err != nil {
return types.SignedHeader{}, err
}
return sh, nil
}
You can’t perform that action at this time.