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add new helper functions #329

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merged 2 commits into from
Mar 28, 2022
Merged

add new helper functions #329

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6ab9252
add new helper functions
ukane-philemon Mar 16, 2022
746e7d9
review: refactor errors strings and return values
ukane-philemon Mar 17, 2022
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75 changes: 65 additions & 10 deletions webapi/helpers.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ import (
"github.com/decred/dcrd/dcrec/secp256k1/v4"
"github.com/decred/dcrd/dcrutil/v4"
"github.com/decred/dcrd/wire"
"github.com/gin-gonic/gin"
"github.com/decred/vspd/rpc"
)

func currentVoteVersion(params *chaincfg.Params) uint32 {
Expand Down Expand Up @@ -105,16 +105,22 @@ func validPolicyOption(policy string) error {
}
}

func validateSignature(reqBytes []byte, commitmentAddress string, c *gin.Context) error {
// Ensure a signature is provided.
signature := c.GetHeader("VSP-Client-Signature")
if signature == "" {
return errors.New("no VSP-Client-Signature header")
}
func validateSignature(hash, commitmentAddress, signature, message string) error {
firstErr := dcrutil.VerifyMessage(commitmentAddress, signature, message, cfg.NetParams)
if firstErr != nil {
// Don't return an error straight away if sig validation fails -
// first check if we have an alternate sign address for this ticket.
altSigData, err := db.AltSignAddrData(hash)
if err != nil {
return fmt.Errorf("db.AltSignAddrData failed: %v", err)
}

// If we have no alternate sign address, or if validating with the
// alt sign addr fails, return an error to the client.
if altSigData == nil || dcrutil.VerifyMessage(altSigData.AltSignAddr, signature, message, cfg.NetParams) != nil {
return fmt.Errorf("bad signature")
}

err := dcrutil.VerifyMessage(commitmentAddress, signature, string(reqBytes), cfg.NetParams)
if err != nil {
return err
}
return nil
}
Expand All @@ -141,3 +147,52 @@ func isValidTicket(tx *wire.MsgTx) error {

return nil
}

// validateTicketHash ensures the provided ticket hash is a valid ticket hash.
// A ticket hash should be 64 chars (MaxHashStringSize) and should parse into
// a chainhash.Hash without error.
func validateTicketHash(hash string) error {
if len(hash) != chainhash.MaxHashStringSize {
return fmt.Errorf("incorrect hash length: got %d, expected %d", len(hash), chainhash.MaxHashStringSize)

}
_, err := chainhash.NewHashFromStr(hash)
if err != nil {
return fmt.Errorf("invalid hash: %v", err)

}

return nil
}

// getCommitmentAddress gets the commitment address of the provided ticket hash
// from the chain.
func getCommitmentAddress(hash string, dcrdClient *rpc.DcrdRPC) (string, error) {
var commitmentAddress string
resp, err := dcrdClient.GetRawTransaction(hash)
if err != nil {
return commitmentAddress, fmt.Errorf("dcrd.GetRawTransaction for ticket failed: %v", err)

}

msgTx, err := decodeTransaction(resp.Hex)
if err != nil {
return commitmentAddress, fmt.Errorf("Failed to decode ticket hex: %v", err)

}

err = isValidTicket(msgTx)
if err != nil {
return commitmentAddress, fmt.Errorf("Invalid ticket: %w", errInvalidTicket)

}

addr, err := stake.AddrFromSStxPkScrCommitment(msgTx.TxOut[1].PkScript, cfg.NetParams)
if err != nil {
return commitmentAddress, fmt.Errorf("AddrFromSStxPkScrCommitment error: %v", err)

}

commitmentAddress = addr.String()
return commitmentAddress, nil
}
91 changes: 29 additions & 62 deletions webapi/middleware.go
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,6 @@ import (
"net/http"
"strings"

"github.com/decred/dcrd/blockchain/stake/v4"
"github.com/decred/dcrd/chaincfg/chainhash"
"github.com/decred/vspd/rpc"
"github.com/gin-gonic/gin"
"github.com/gin-gonic/gin/binding"
Expand Down Expand Up @@ -287,17 +285,9 @@ func vspAuth() gin.HandlerFunc {
hash := request.TicketHash

// Before hitting the db or any RPC, ensure this is a valid ticket hash.
// A ticket hash should be 64 chars (MaxHashStringSize) and should parse
// into a chainhash.Hash without error.
if len(hash) != chainhash.MaxHashStringSize {
log.Errorf("%s: Incorrect hash length (clientIP=%s): got %d, expected %d",
funcName, c.ClientIP(), len(hash), chainhash.MaxHashStringSize)
sendErrorWithMsg("invalid ticket hash", errBadRequest, c)
return
}
_, err = chainhash.NewHashFromStr(hash)
err = validateTicketHash(hash)
if err != nil {
log.Errorf("%s: Invalid hash (clientIP=%s): %v", funcName, c.ClientIP(), err)
log.Errorf("%s: Bad request (clientIP=%s): %v", funcName, c.ClientIP(), err)
sendErrorWithMsg("invalid ticket hash", errBadRequest, c)
return
}
Expand All @@ -313,67 +303,44 @@ func vspAuth() gin.HandlerFunc {
// If the ticket was found in the database, we already know its
// commitment address. Otherwise we need to get it from the chain.
var commitmentAddress string
dcrdClient := c.MustGet(dcrdKey).(*rpc.DcrdRPC)
dcrdErr := c.MustGet(dcrdErrorKey)
if dcrdErr != nil {
log.Errorf("%s: could not get dcrd client: %v", funcName, dcrdErr.(error))
sendError(errInternalError, c)
return
}

if ticketFound {
commitmentAddress = ticket.CommitmentAddress
} else {
dcrdClient := c.MustGet(dcrdKey).(*rpc.DcrdRPC)
dcrdErr := c.MustGet(dcrdErrorKey)
if dcrdErr != nil {
log.Errorf("%s: could not get dcrd client: %v", funcName, dcrdErr.(error))
sendError(errInternalError, c)
return
}

resp, err := dcrdClient.GetRawTransaction(hash)
commitmentAddress, err = getCommitmentAddress(hash, dcrdClient)
if err != nil {
log.Errorf("%s: dcrd.GetRawTransaction for ticket failed (ticketHash=%s): %v", funcName, hash, err)
sendError(errInternalError, c)
return
}

msgTx, err := decodeTransaction(resp.Hex)
if err != nil {
log.Errorf("%s: Failed to decode ticket hex (ticketHash=%s): %v", funcName, ticket.Hash, err)
sendError(errInternalError, c)
return
}

err = isValidTicket(msgTx)
if err != nil {
log.Warnf("%s: Invalid ticket (clientIP=%s, ticketHash=%s): %v", funcName, c.ClientIP(), hash, err)
sendError(errInvalidTicket, c)
return
}

addr, err := stake.AddrFromSStxPkScrCommitment(msgTx.TxOut[1].PkScript, cfg.NetParams)
if err != nil {
log.Errorf("%s: AddrFromSStxPkScrCommitment error (ticketHash=%s): %v", funcName, hash, err)
sendError(errInternalError, c)
var apiErr *apiError
if errors.Is(err, apiErr) {
sendError(errInvalidTicket, c)
} else {
sendError(errInternalError, c)
}
log.Errorf("%s: (clientIP: %s, ticketHash: %s): %v", funcName, c.ClientIP(), hash, err)
return
}
}

commitmentAddress = addr.String()
// Ensure a signature is provided.
signature := c.GetHeader("VSP-Client-Signature")
if signature == "" {
log.Warnf("%s: Bad request (clientIP=%s): %v", funcName, c.ClientIP(), err)
sendErrorWithMsg("no VSP-Client-Signature header", errBadRequest, c)
return
}

// Validate request signature to ensure ticket ownership.
err = validateSignature(reqBytes, commitmentAddress, c)
err = validateSignature(hash, commitmentAddress, signature, string(reqBytes))
if err != nil {
// Don't return an error straight away if sig validation fails -
// first check if we have an alternate sign address for this ticket.
altSigData, err := db.AltSignAddrData(hash)
if err != nil {
log.Errorf("%s: db.AltSignAddrData failed (ticketHash=%s): %v", funcName, hash, err)
sendError(errInternalError, c)
return
}

// If we have no alternate sign address, or if validating with the
// alt sign addr fails, return an error to the client.
if altSigData == nil || validateSignature(reqBytes, altSigData.AltSignAddr, c) != nil {
log.Warnf("%s: Bad signature (clientIP=%s, ticketHash=%s)", funcName, c.ClientIP(), hash)
sendError(errBadSignature, c)
return
}
log.Errorf("%s: Bad signature (clientIP=%s, ticketHash=%s): %v", funcName, err)
sendError(errBadSignature, c)
return
}

// Add ticket information to context so downstream handlers don't need
Expand Down