fastcgi: strip PATH_INFO from SCRIPT_FILENAME (mirroring SCRIPT_NAME)

caddyhttp/fastcgi/fastcgi.go

@@ -242,9 +242,6 @@ func (h Handler) exists(path string) bool {
 func (h Handler) buildEnv(r *http.Request, rule Rule, fpath string) (map[string]string, error) {
 	var env map[string]string
 
-	// Get absolute path of requested resource
-	absPath := filepath.Join(rule.Root, fpath)
-
 	// Separate remote IP and port; more lenient than net.SplitHostPort
 	var ip, port string
 	if idx := strings.LastIndex(r.RemoteAddr, ":"); idx > -1 {
@@ -266,11 +263,13 @@ func (h Handler) buildEnv(r *http.Request, rule Rule, fpath string) (map[string]
 	docURI := fpath[:splitPos+len(rule.SplitPath)]
 	pathInfo := fpath[splitPos+len(rule.SplitPath):]
 	scriptName := fpath
-	scriptFilename := absPath
 
 	// Strip PATH_INFO from SCRIPT_NAME
 	scriptName = strings.TrimSuffix(scriptName, pathInfo)
 
+	// SCRIPT_FILENAME is the absolute path of SCRIPT_NAME
+	scriptFilename := filepath.Join(rule.Root, scriptName)
+
 	// Add vhost path prefix to scriptName. Otherwise, some PHP software will
 	// have difficulty discovering its URL.
 	pathPrefix, _ := r.Context().Value(caddy.CtxKey("path_prefix")).(string)

caddyhttp/fastcgi/fastcgi_test.go

@@ -21,6 +21,7 @@ import (
 	"net/http/fcgi"
 	"net/http/httptest"
 	"net/url"
+	"path/filepath"
 	"strconv"
 	"sync"
 	"testing"
@@ -238,6 +239,15 @@ func TestBuildEnv(t *testing.T) {
 	envExpected = newEnv()
 	envExpected["SCRIPT_NAME"] = "/test/fgci_test.php"
 	testBuildEnv(r, rule, fpath, envExpected)
+
+	// 7. Test SCRIPT_NAME,SCRIPT_FILENAME do not include PATH_INFO
+	fpath = "/fgci_test.php/extra/paths"
+	r = newReq()
+	envExpected = newEnv()
+	envExpected["PATH_INFO"] = "/extra/paths"
+	envExpected["SCRIPT_NAME"] = "/fgci_test.php"
+	envExpected["SCRIPT_FILENAME"] = filepath.FromSlash("/fgci_test.php")
+	testBuildEnv(r, rule, fpath, envExpected)
 }
 
 func TestReadTimeout(t *testing.T) {