sigs.k8s.io/prow@v0.0.0-20240503223140-c5e374dc7eb1/pkg/github/webhooks.go (about)

     1  /*
     2  Copyright 2017 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package github
    18  
    19  import (
    20  	"io"
    21  	"net/http"
    22  
    23  	"github.com/sirupsen/logrus"
    24  )
    25  
    26  // ValidateWebhook ensures that the provided request conforms to the
    27  // format of a GitHub webhook and the payload can be validated with
    28  // the provided hmac secret. It returns the event type, the event guid,
    29  // the payload of the request, whether the webhook is valid or not,
    30  // and finally the resultant HTTP status code
    31  func ValidateWebhook(w http.ResponseWriter, r *http.Request, tokenGenerator func() []byte) (string, string, []byte, bool, int) {
    32  	defer r.Body.Close()
    33  
    34  	// Header checks: It must be a POST with an event type and a signature.
    35  	if r.Method != http.MethodPost {
    36  		responseHTTPError(w, http.StatusMethodNotAllowed, "405 Method not allowed")
    37  		return "", "", nil, false, http.StatusMethodNotAllowed
    38  	}
    39  	eventType := r.Header.Get("X-GitHub-Event")
    40  	if eventType == "" {
    41  		responseHTTPError(w, http.StatusBadRequest, "400 Bad Request: Missing X-GitHub-Event Header")
    42  		return "", "", nil, false, http.StatusBadRequest
    43  	}
    44  	eventGUID := r.Header.Get("X-GitHub-Delivery")
    45  	if eventGUID == "" {
    46  		responseHTTPError(w, http.StatusBadRequest, "400 Bad Request: Missing X-GitHub-Delivery Header")
    47  		return "", "", nil, false, http.StatusBadRequest
    48  	}
    49  	sig := r.Header.Get("X-Hub-Signature")
    50  	if sig == "" {
    51  		responseHTTPError(w, http.StatusForbidden, "403 Forbidden: Missing X-Hub-Signature")
    52  		return "", "", nil, false, http.StatusForbidden
    53  	}
    54  	contentType := r.Header.Get("content-type")
    55  	if contentType != "application/json" {
    56  		responseHTTPError(w, http.StatusBadRequest, "400 Bad Request: Hook only accepts content-type: application/json - please reconfigure this hook on GitHub")
    57  		return "", "", nil, false, http.StatusBadRequest
    58  	}
    59  	payload, err := io.ReadAll(r.Body)
    60  	if err != nil {
    61  		responseHTTPError(w, http.StatusInternalServerError, "500 Internal Server Error: Failed to read request body")
    62  		return "", "", nil, false, http.StatusInternalServerError
    63  	}
    64  	// Validate the payload with our HMAC secret.
    65  	if !ValidatePayload(payload, sig, tokenGenerator) {
    66  		responseHTTPError(w, http.StatusForbidden, "403 Forbidden: Invalid X-Hub-Signature")
    67  		return "", "", nil, false, http.StatusForbidden
    68  	}
    69  
    70  	return eventType, eventGUID, payload, true, http.StatusOK
    71  }
    72  
    73  func responseHTTPError(w http.ResponseWriter, statusCode int, response string) {
    74  	logrus.WithFields(logrus.Fields{
    75  		"response":    response,
    76  		"status-code": statusCode,
    77  	}).Debug(response)
    78  	http.Error(w, response, statusCode)
    79  }