mirror of https://github.com/coder/coder.git
92 lines
3.2 KiB
Go
92 lines
3.2 KiB
Go
package httpmw
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import (
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"net/http"
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"regexp"
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"strings"
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"github.com/justinas/nosurf"
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"golang.org/x/xerrors"
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"github.com/coder/coder/v2/codersdk"
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)
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// CSRF is a middleware that verifies that a CSRF token is present in the request
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// for non-GET requests.
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// If enforce is false, then CSRF enforcement is disabled. We still want
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// to include the CSRF middleware because it will set the CSRF cookie.
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func CSRF(secureCookie bool) func(next http.Handler) http.Handler {
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return func(next http.Handler) http.Handler {
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mw := nosurf.New(next)
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mw.SetBaseCookie(http.Cookie{Path: "/", HttpOnly: true, SameSite: http.SameSiteLaxMode, Secure: secureCookie})
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mw.SetFailureHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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http.Error(w, "Something is wrong with your CSRF token. Please refresh the page. If this error persists, try clearing your cookies.", http.StatusBadRequest)
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}))
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mw.ExemptRegexp(regexp.MustCompile("/api/v2/users/first"))
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// Exempt all requests that do not require CSRF protection.
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// All GET requests are exempt by default.
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mw.ExemptPath("/api/v2/csp/reports")
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// This should not be required?
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mw.ExemptRegexp(regexp.MustCompile("/api/v2/users/first"))
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// Agent authenticated routes
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mw.ExemptRegexp(regexp.MustCompile("api/v2/workspaceagents/me/*"))
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mw.ExemptRegexp(regexp.MustCompile("api/v2/workspaceagents/*"))
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// Workspace Proxy routes
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mw.ExemptRegexp(regexp.MustCompile("api/v2/workspaceproxies/me/*"))
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// Derp routes
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mw.ExemptRegexp(regexp.MustCompile("derp/*"))
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// Scim
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mw.ExemptRegexp(regexp.MustCompile("api/v2/scim/*"))
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// Provisioner daemon routes
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mw.ExemptRegexp(regexp.MustCompile("/organizations/[^/]+/provisionerdaemons/*"))
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mw.ExemptFunc(func(r *http.Request) bool {
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// Only enforce CSRF on API routes.
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if !strings.HasPrefix(r.URL.Path, "/api") {
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return true
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}
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// CSRF only affects requests that automatically attach credentials via a cookie.
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// If no cookie is present, then there is no risk of CSRF.
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//nolint:govet
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sessCookie, err := r.Cookie(codersdk.SessionTokenCookie)
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if xerrors.Is(err, http.ErrNoCookie) {
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return true
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}
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if token := r.Header.Get(codersdk.SessionTokenHeader); token == sessCookie.Value {
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// If the cookie and header match, we can assume this is the same as just using the
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// custom header auth. Custom header auth can bypass CSRF, as CSRF attacks
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// cannot add custom headers.
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return true
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}
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if token := r.URL.Query().Get(codersdk.SessionTokenCookie); token == sessCookie.Value {
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// If the auth is set in a url param and matches the cookie, it
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// is the same as just using the url param.
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return true
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}
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if r.Header.Get(codersdk.ProvisionerDaemonPSK) != "" {
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// If present, the provisioner daemon also is providing an api key
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// that will make them exempt from CSRF. But this is still useful
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// for enumerating the external auths.
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return true
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}
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// If the X-CSRF-TOKEN header is set, we can exempt the func if it's valid.
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// This is the CSRF check.
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sent := r.Header.Get("X-CSRF-TOKEN")
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if sent != "" {
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return nosurf.VerifyToken(nosurf.Token(r), sent)
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}
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return false
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})
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return mw
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}
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}
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