JS FS: Don't return ELOOP on a path with a large number of ..'s (#24591)

hoodmane · web-flow · commit cc1de1af3f5a · 2025-06-18T08:44:44.000-07:00
Decrement nlinks before doing `continue linkloop;` due to a .. at a file
system loop. We're not actually traversing a symlink here.

Caught by the Python test suite.
diff --git a/src/lib/libfs.js b/src/lib/libfs.js
@@ -197,6 +197,9 @@ FS.staticInit();`;
             current_path = PATH.dirname(current_path);
             if (FS.isRoot(current)) {
               path = current_path + '/' + parts.slice(i + 1).join('/');
+              // We're making progress here, don't let many consecutive ..'s
+              // lead to ELOOP
+              nlinks--;
               continue linkloop;
             } else {
               current = current.parent;
diff --git a/test/other/codesize/test_codesize_cxx_ctors1.gzsize b/test/other/codesize/test_codesize_cxx_ctors1.gzsize
@@ -1 +1 @@
-8167
+8171
diff --git a/test/other/codesize/test_codesize_cxx_ctors1.jssize b/test/other/codesize/test_codesize_cxx_ctors1.jssize
@@ -1 +1 @@
-19798
+19802
diff --git a/test/other/codesize/test_codesize_cxx_ctors2.gzsize b/test/other/codesize/test_codesize_cxx_ctors2.gzsize
@@ -1 +1 @@
-8155
+8160
diff --git a/test/other/codesize/test_codesize_cxx_ctors2.jssize b/test/other/codesize/test_codesize_cxx_ctors2.jssize
@@ -1 +1 @@
-19776
+19780
diff --git a/test/other/codesize/test_codesize_cxx_except.gzsize b/test/other/codesize/test_codesize_cxx_except.gzsize
@@ -1 +1 @@
-9154
+9159
diff --git a/test/other/codesize/test_codesize_cxx_except.jssize b/test/other/codesize/test_codesize_cxx_except.jssize
@@ -1 +1 @@
-23459
+23463
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm.gzsize
@@ -1 +1 @@
-8115
+8119
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm.jssize b/test/other/codesize/test_codesize_cxx_except_wasm.jssize
@@ -1 +1 @@
-19687
+19691
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_legacy.gzsize b/test/other/codesize/test_codesize_cxx_except_wasm_legacy.gzsize
@@ -1 +1 @@
-8115
+8119
diff --git a/test/other/codesize/test_codesize_cxx_except_wasm_legacy.jssize b/test/other/codesize/test_codesize_cxx_except_wasm_legacy.jssize
@@ -1 +1 @@
-19687
+19691
diff --git a/test/other/codesize/test_codesize_cxx_lto.gzsize b/test/other/codesize/test_codesize_cxx_lto.gzsize
@@ -1 +1 @@
-8019
+8023
diff --git a/test/other/codesize/test_codesize_cxx_lto.jssize b/test/other/codesize/test_codesize_cxx_lto.jssize
@@ -1 +1 @@
-19502
+19506
diff --git a/test/other/codesize/test_codesize_cxx_mangle.gzsize b/test/other/codesize/test_codesize_cxx_mangle.gzsize
@@ -1 +1 @@
-9171
+9176
diff --git a/test/other/codesize/test_codesize_cxx_mangle.jssize b/test/other/codesize/test_codesize_cxx_mangle.jssize
@@ -1 +1 @@
-23509
+23513
diff --git a/test/other/codesize/test_codesize_cxx_noexcept.gzsize b/test/other/codesize/test_codesize_cxx_noexcept.gzsize
@@ -1 +1 @@
-8167
+8171
diff --git a/test/other/codesize/test_codesize_cxx_noexcept.jssize b/test/other/codesize/test_codesize_cxx_noexcept.jssize
@@ -1 +1 @@
-19798
+19802
diff --git a/test/other/codesize/test_codesize_files_js_fs.gzsize b/test/other/codesize/test_codesize_files_js_fs.gzsize
@@ -1 +1 @@
-7480
+7485
diff --git a/test/other/codesize/test_codesize_files_js_fs.jssize b/test/other/codesize/test_codesize_files_js_fs.jssize
@@ -1 +1 @@
-18401
+18405
diff --git a/test/other/codesize/test_codesize_hello_dylink.gzsize b/test/other/codesize/test_codesize_hello_dylink.gzsize
@@ -1 +1 @@
-11562
+11568
diff --git a/test/other/codesize/test_codesize_hello_dylink.jssize b/test/other/codesize/test_codesize_hello_dylink.jssize
@@ -1 +1 @@
-27310
+27314
diff --git a/test/test_other.py b/test/test_other.py
@@ -6070,6 +6070,21 @@ def test_symlink_silly(self):
     self.assertContained(r'ok', self.run_js('a.out.js', args=['123', 'abc']))
     self.assertContained(r'Failed to symlink paths: abc, ; errno=44', self.run_js('a.out.js', args=['abc', '']))
 
+  @with_all_fs
+  def test_stat_many_dotdot(self):
+    path = "/".join([".."] * 75)
+    create_file('main.c', '''
+      #include <stdio.h>
+      #include <errno.h>
+      #include <sys/stat.h>
+
+      int main() {
+        struct stat path_stat;
+        return stat("%s", &path_stat);
+      }
+    ''' % path)
+    self.do_runf('main.c')
+
   def test_rename_silly(self):
     create_file('src.c', r'''
 #include <stdio.h>
