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Cleanup request error handling; properly handle os.ErrNotExist errors (#150)

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This commit is contained in:
Dane Everitt
2022-11-22 10:18:27 -08:00
committed by GitHub
parent 9226ccae31
commit ff50d0e5bd
13 changed files with 236 additions and 341 deletions
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129
router/middleware/middleware.go
View File

@@ -1,11 +1,9 @@
package middleware
import (
"context"
"crypto/subtle"
"io"
"net/http"
"os"
"strings"
"emperror.dev/errors"
@@ -16,133 +14,8 @@ import (
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/remote"
"github.com/pterodactyl/wings/server"
"github.com/pterodactyl/wings/server/filesystem"
)
// RequestError is a custom error type returned when something goes wrong with
// any of the HTTP endpoints.
type RequestError struct {
err error
status int
msg string
}
// NewError returns a new RequestError for the provided error.
func NewError(err error) *RequestError {
return &RequestError{
// Attach a stacktrace to the error if it is missing at this point and mark it
// as originating from the location where NewError was called, rather than this
// specific point in the code.
err: errors.WithStackDepthIf(err, 1),
}
}
// SetMessage allows for a custom error message to be set on an existing
// RequestError instance.
func (re *RequestError) SetMessage(m string) {
re.msg = m
}
// SetStatus sets the HTTP status code for the error response. By default this
// is a HTTP-500 error.
func (re *RequestError) SetStatus(s int) {
re.status = s
}
// Abort aborts the given HTTP request with the specified status code and then
// logs the event into the logs. The error that is output will include the unique
// request ID if it is present.
func (re *RequestError) Abort(c *gin.Context, status int) {
reqId := c.Writer.Header().Get("X-Request-Id")
// Generate the base logger instance, attaching the unique request ID and
// the URL that was requested.
event := log.WithField("request_id", reqId).WithField("url", c.Request.URL.String())
// If there is a server present in the gin.Context stack go ahead and pull it
// and attach that server UUID to the logs as well so that we can see what specific
// server triggered this error.
if s, ok := c.Get("server"); ok {
if s, ok := s.(*server.Server); ok {
event = event.WithField("server_id", s.ID())
}
}
if c.Writer.Status() == 200 {
// Handle context deadlines being exceeded a little differently since we want
// to report a more user-friendly error and a proper error code. The "context
// canceled" error is generally when a request is terminated before all of the
// logic is finished running.
if errors.Is(re.err, context.DeadlineExceeded) {
re.SetStatus(http.StatusGatewayTimeout)
re.SetMessage("The server could not process this request in time, please try again.")
} else if strings.Contains(re.Cause().Error(), "context canceled") {
re.SetStatus(http.StatusBadRequest)
re.SetMessage("Request aborted by client.")
}
}
// c.Writer.Status() will be a non-200 value if the headers have already been sent
// to the requester but an error is encountered. This can happen if there is an issue
// marshaling a struct placed into a c.JSON() call (or c.AbortWithJSON() call).
if status >= 500 || c.Writer.Status() != 200 {
event.WithField("status", status).WithField("error", re.err).Error("error while handling HTTP request")
} else {
event.WithField("status", status).WithField("error", re.err).Debug("error handling HTTP request (not a server error)")
}
if re.msg == "" {
re.msg = "An unexpected error was encountered while processing this request"
}
// Now abort the request with the error message and include the unique request
// ID that was present to make things super easy on people who don't know how
// or cannot view the response headers (where X-Request-Id would be present).
c.AbortWithStatusJSON(status, gin.H{"error": re.msg, "request_id": reqId})
}
// Cause returns the underlying error.
func (re *RequestError) Cause() error {
return re.err
}
// Error returns the underlying error message for this request.
func (re *RequestError) Error() string {
return re.err.Error()
}
// Looks at the given RequestError and determines if it is a specific filesystem
// error that we can process and return differently for the user.
//
// Some external things end up calling fmt.Errorf() on our filesystem errors
// which ends up just unleashing chaos on the system. For the sake of this,
// fallback to using text checks.
//
// If the error passed into this call is nil or does not match empty values will
// be returned to the caller.
func (re *RequestError) asFilesystemError() (int, string) {
err := re.Cause()
if err == nil {
return 0, ""
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeDenylistFile) || strings.Contains(err.Error(), "filesystem: file access prohibited") {
return http.StatusForbidden, "This file cannot be modified: present in egg denylist."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodePathResolution) || strings.Contains(err.Error(), "resolves to a location outside the server root") {
return http.StatusNotFound, "The requested resource was not found on the system."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeIsDirectory) || strings.Contains(err.Error(), "filesystem: is a directory") {
return http.StatusBadRequest, "Cannot perform that action: file is a directory."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeDiskSpace) || strings.Contains(err.Error(), "filesystem: not enough disk space") {
return http.StatusBadRequest, "There is not enough disk space available to perform that action."
}
if strings.HasSuffix(err.Error(), "file name too long") {
return http.StatusBadRequest, "Cannot perform that action: file name is too long."
}
if e, ok := err.(*os.SyscallError); ok && e.Syscall == "readdirent" {
return http.StatusNotFound, "The requested directory does not exist."
}
return 0, ""
}
// AttachRequestID attaches a unique ID to the incoming HTTP request so that any
// errors that are generated or returned to the client will include this reference
// allowing for an easier time identifying the specific request that failed for
@@ -180,7 +53,7 @@ func AttachApiClient(client remote.Client) gin.HandlerFunc {
}
// CaptureAndAbort aborts the request and attaches the provided error to the gin
// context so it can be reported properly. If the error is missing a stacktrace
// context, so it can be reported properly. If the error is missing a stacktrace
// at the time it is called the stack will be attached.
func CaptureAndAbort(c *gin.Context, err error) {
c.Abort()

141
router/middleware/request_error.go Normal file
View File

@@ -0,0 +1,141 @@
package middleware
import (
"context"
"net/http"
"os"
"strings"
"emperror.dev/errors"
"github.com/apex/log"
"github.com/gin-gonic/gin"
"github.com/pterodactyl/wings/server"
"github.com/pterodactyl/wings/server/filesystem"
)
// RequestError is a custom error type returned when something goes wrong with
// any of the HTTP endpoints.
type RequestError struct {
err error
status int
msg string
}
// NewError returns a new RequestError for the provided error.
func NewError(err error) *RequestError {
return &RequestError{
// Attach a stacktrace to the error if it is missing at this point and mark it
// as originating from the location where NewError was called, rather than this
// specific point in the code.
err: errors.WithStackDepthIf(err, 1),
}
}
// SetMessage allows for a custom error message to be set on an existing
// RequestError instance.
func (re *RequestError) SetMessage(m string) {
re.msg = m
}
// SetStatus sets the HTTP status code for the error response. By default this
// is a HTTP-500 error.
func (re *RequestError) SetStatus(s int) {
re.status = s
}
// Abort aborts the given HTTP request with the specified status code and then
// logs the event into the logs. The error that is output will include the unique
// request ID if it is present.
func (re *RequestError) Abort(c *gin.Context, status int) {
reqId := c.Writer.Header().Get("X-Request-Id")
// Generate the base logger instance, attaching the unique request ID and
// the URL that was requested.
event := log.WithField("request_id", reqId).WithField("url", c.Request.URL.String())
// If there is a server present in the gin.Context stack go ahead and pull it
// and attach that server UUID to the logs as well so that we can see what specific
// server triggered this error.
if s, ok := c.Get("server"); ok {
if s, ok := s.(*server.Server); ok {
event = event.WithField("server_id", s.ID())
}
}
if c.Writer.Status() == 200 {
// Handle context deadlines being exceeded a little differently since we want
// to report a more user-friendly error and a proper error code. The "context
// canceled" error is generally when a request is terminated before all of the
// logic is finished running.
if errors.Is(re.err, context.DeadlineExceeded) {
re.SetStatus(http.StatusGatewayTimeout)
re.SetMessage("The server could not process this request in time, please try again.")
} else if strings.Contains(re.Cause().Error(), "context canceled") {
re.SetStatus(http.StatusBadRequest)
re.SetMessage("Request aborted by client.")
}
}
// c.Writer.Status() will be a non-200 value if the headers have already been sent
// to the requester but an error is encountered. This can happen if there is an issue
// marshaling a struct placed into a c.JSON() call (or c.AbortWithJSON() call).
if status >= 500 || c.Writer.Status() != 200 {
event.WithField("status", status).WithField("error", re.err).Error("error while handling HTTP request")
} else {
event.WithField("status", status).WithField("error", re.err).Debug("error handling HTTP request (not a server error)")
}
if re.msg == "" {
re.msg = "An unexpected error was encountered while processing this request"
}
// Now abort the request with the error message and include the unique request
// ID that was present to make things super easy on people who don't know how
// or cannot view the response headers (where X-Request-Id would be present).
c.AbortWithStatusJSON(status, gin.H{"error": re.msg, "request_id": reqId})
}
// Cause returns the underlying error.
func (re *RequestError) Cause() error {
return re.err
}
// Error returns the underlying error message for this request.
func (re *RequestError) Error() string {
return re.err.Error()
}
// Looks at the given RequestError and determines if it is a specific filesystem
// error that we can process and return differently for the user.
//
// Some external things end up calling fmt.Errorf() on our filesystem errors
// which ends up just unleashing chaos on the system. For the sake of this,
// fallback to using text checks.
//
// If the error passed into this call is nil or does not match empty values will
// be returned to the caller.
func (re *RequestError) asFilesystemError() (int, string) {
err := re.Cause()
if err == nil {
return 0, ""
}
if filesystem.IsErrorCode(err, filesystem.ErrNotExist) ||
filesystem.IsErrorCode(err, filesystem.ErrCodePathResolution) ||
strings.Contains(err.Error(), "resolves to a location outside the server root") {
return http.StatusNotFound, "The requested resources was not found on the system."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeDenylistFile) || strings.Contains(err.Error(), "filesystem: file access prohibited") {
return http.StatusForbidden, "This file cannot be modified: present in egg denylist."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeIsDirectory) || strings.Contains(err.Error(), "filesystem: is a directory") {
return http.StatusBadRequest, "Cannot perform that action: file is a directory."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeDiskSpace) || strings.Contains(err.Error(), "filesystem: not enough disk space") {
return http.StatusBadRequest, "There is not enough disk space available to perform that action."
}
if strings.HasSuffix(err.Error(), "file name too long") {
return http.StatusBadRequest, "Cannot perform that action: file name is too long."
}
if e, ok := err.(*os.SyscallError); ok && e.Syscall == "readdirent" {
return http.StatusNotFound, "The requested directory does not exist."
}
return 0, ""
}