package sqs import ( "crypto/md5" "encoding/hex" "fmt" "strings" "github.com/aws/aws-sdk-go/aws" "github.com/aws/aws-sdk-go/aws/awserr" "github.com/aws/aws-sdk-go/aws/request" ) var ( errChecksumMissingBody = fmt.Errorf("cannot compute checksum. missing body") errChecksumMissingMD5 = fmt.Errorf("cannot verify checksum. missing response MD5") ) func setupChecksumValidation(r *request.Request) { if aws.BoolValue(r.Config.DisableComputeChecksums) { return } switch r.Operation.Name { case opSendMessage: r.Handlers.Unmarshal.PushBack(verifySendMessage) case opSendMessageBatch: r.Handlers.Unmarshal.PushBack(verifySendMessageBatch) case opReceiveMessage: r.Handlers.Unmarshal.PushBack(verifyReceiveMessage) } } func verifySendMessage(r *request.Request) { if r.DataFilled() && r.ParamsFilled() { in := r.Params.(*SendMessageInput) out := r.Data.(*SendMessageOutput) err := checksumsMatch(in.MessageBody, out.MD5OfMessageBody) if err != nil { setChecksumError(r, err.Error()) } } } func verifySendMessageBatch(r *request.Request) { if r.DataFilled() && r.ParamsFilled() { entries := map[string]*SendMessageBatchResultEntry{} ids := []string{} out := r.Data.(*SendMessageBatchOutput) for _, entry := range out.Successful { entries[*entry.Id] = entry } in := r.Params.(*SendMessageBatchInput) for _, entry := range in.Entries { if e := entries[*entry.Id]; e != nil { err := checksumsMatch(entry.MessageBody, e.MD5OfMessageBody) if err != nil { ids = append(ids, *e.MessageId) } } } if len(ids) > 0 { setChecksumError(r, "invalid messages: %s", strings.Join(ids, ", ")) } } } func verifyReceiveMessage(r *request.Request) { if r.DataFilled() && r.ParamsFilled() { ids := []string{} out := r.Data.(*ReceiveMessageOutput) for _, msg := range out.Messages { err := checksumsMatch(msg.Body, msg.MD5OfBody) if err != nil { ids = append(ids, *msg.MessageId) } } if len(ids) > 0 { setChecksumError(r, "invalid messages: %s", strings.Join(ids, ", ")) } } } func checksumsMatch(body, expectedMD5 *string) error { if body == nil { return errChecksumMissingBody } else if expectedMD5 == nil { return errChecksumMissingMD5 } msum := md5.Sum([]byte(*body)) sum := hex.EncodeToString(msum[:]) if sum != *expectedMD5 { return fmt.Errorf("expected MD5 checksum '%s', got '%s'", *expectedMD5, sum) } return nil } func setChecksumError(r *request.Request, format string, args ...interface{}) { r.Retryable = aws.Bool(true) r.Error = awserr.New("InvalidChecksum", fmt.Sprintf(format, args...), nil) }