lib: handle all windows reserved driver name

Signed-off-by: RafaelGSS <[email protected]>
PR-URL: nodejs-private/node-private#721
Refs: https://hackerone.com/reports/3160912
CVE-ID: CVE-2025-27210

Author: RafaelGSS

lib/path.js

@@ -22,6 +22,7 @@
 'use strict';
 
 const {
+  ArrayPrototypeIncludes,
   ArrayPrototypeJoin,
   ArrayPrototypeSlice,
   FunctionPrototypeBind,
@@ -34,6 +35,7 @@ const {
   StringPrototypeSlice,
   StringPrototypeSplit,
   StringPrototypeToLowerCase,
+  StringPrototypeToUpperCase,
 } = primordials;
 
 const {
@@ -67,6 +69,17 @@ function isPosixPathSeparator(code) {
   return code === CHAR_FORWARD_SLASH;
 }
 
+const WINDOWS_RESERVED_NAMES = [
+  'CON', 'PRN', 'AUX', 'NUL',
+  'COM1', 'COM2', 'COM3', 'COM4', 'COM5', 'COM6', 'COM7', 'COM8', 'COM9',
+  'LPT1', 'LPT2', 'LPT3', 'LPT4', 'LPT5', 'LPT6', 'LPT7', 'LPT8', 'LPT9',
+];
+
+function isWindowsReservedName(path, colonIndex) {
+  const devicePart = StringPrototypeToUpperCase(StringPrototypeSlice(path, 0, colonIndex));
+  return ArrayPrototypeIncludes(WINDOWS_RESERVED_NAMES, devicePart);
+}
+
 function isWindowsDeviceRoot(code) {
   return (code >= CHAR_UPPERCASE_A && code <= CHAR_UPPERCASE_Z) ||
          (code >= CHAR_LOWERCASE_A && code <= CHAR_LOWERCASE_Z);
@@ -402,16 +415,21 @@ const win32 = {
       } else {
         rootEnd = 1;
       }
-    } else if (isWindowsDeviceRoot(code) &&
-               StringPrototypeCharCodeAt(path, 1) === CHAR_COLON) {
-      // Possible device root
-      device = StringPrototypeSlice(path, 0, 2);
-      rootEnd = 2;
-      if (len > 2 && isPathSeparator(StringPrototypeCharCodeAt(path, 2))) {
-        // Treat separator following drive name as an absolute path
-        // indicator
-        isAbsolute = true;
-        rootEnd = 3;
+    } else {
+      const colonIndex = StringPrototypeIndexOf(path, ':');
+      if (colonIndex > 0) {
+        if (isWindowsDeviceRoot(code) && colonIndex === 1) {
+          device = StringPrototypeSlice(path, 0, 2);
+          rootEnd = 2;
+          if (len > 2 && isPathSeparator(StringPrototypeCharCodeAt(path, 2))) {
+            isAbsolute = true;
+            rootEnd = 3;
+          }
+        } else if (isWindowsReservedName(path, colonIndex)) {
+          device = StringPrototypeSlice(path, 0, colonIndex + 1);
+          rootEnd = colonIndex + 1;
+
+        }
       }
     }
 
@@ -435,12 +453,17 @@ const win32 = {
         return `.\\${tail}`;
       }
       let index = StringPrototypeIndexOf(path, ':');
+
       do {
         if (index === len - 1 || isPathSeparator(StringPrototypeCharCodeAt(path, index + 1))) {
           return `.\\${tail}`;
         }
       } while ((index = StringPrototypeIndexOf(path, ':', index + 1)) !== -1);
     }
+    const colonIndex = StringPrototypeIndexOf(path, ':');
+    if (isWindowsReservedName(path, colonIndex)) {
+      return `.\\${device ?? ''}${tail}`;
+    }
     if (device === undefined) {
       return isAbsolute ? `\\${tail}` : tail;
     }

test/parallel/test-path-win32-normalize-device-names.js

@@ -0,0 +1,98 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const path = require('path');
+
+if (!common.isWindows) {
+  common.skip('Windows only');
+}
+
+const normalizeDeviceNameTests = [
+  { input: 'CON', expected: 'CON' },
+  { input: 'con', expected: 'con' },
+  { input: 'CON:', expected: '.\\CON:.' },
+  { input: 'con:', expected: '.\\con:.' },
+  { input: 'CON:.', expected: '.\\CON:.' },
+  { input: 'coN:', expected: '.\\coN:.' },
+  { input: 'LPT9.foo', expected: 'LPT9.foo' },
+  { input: 'COM9:', expected: '.\\COM9:.' },
+  { input: 'COM9.', expected: '.\\COM9.' },
+  { input: 'C:COM9', expected: 'C:COM9' },
+  { input: 'C:\\COM9', expected: 'C:\\COM9' },
+  { input: 'CON:./foo', expected: '.\\CON:foo' },
+  { input: 'CON:/foo', expected: '.\\CON:foo' },
+  { input: 'CON:../foo', expected: '.\\CON:..\\foo' },
+  { input: 'CON:/../foo', expected: '.\\CON:..\\foo' },
+  { input: 'CON:./././foo', expected: '.\\CON:foo' },
+  { input: 'CON:..', expected: '.\\CON:..' },
+  { input: 'CON:..\\', expected: '.\\CON:..\\' },
+  { input: 'CON:..\\..', expected: '.\\CON:..\\..' },
+  { input: 'CON:..\\..\\', expected: '.\\CON:..\\..\\' },
+  { input: 'CON:..\\..\\foo', expected: '.\\CON:..\\..\\foo' },
+  { input: 'CON:..\\..\\foo\\', expected: '.\\CON:..\\..\\foo\\' },
+  { input: 'CON:..\\..\\foo\\bar', expected: '.\\CON:..\\..\\foo\\bar' },
+  { input: 'CON:..\\..\\foo\\bar\\', expected: '.\\CON:..\\..\\foo\\bar\\' },
+  { input: 'COM1:a:b:c', expected: '.\\COM1:a:b:c' },
+  { input: 'COM1:a:b:c/', expected: '.\\COM1:a:b:c\\' },
+  { input: 'c:lpt1', expected: 'c:lpt1' },
+  { input: 'c:\\lpt1', expected: 'c:\\lpt1' },
+
+  // Reserved device names with path traversal
+  { input: 'CON:.\\..\\..\\foo', expected: '.\\CON:..\\..\\foo' },
+  { input: 'PRN:.\\..\\bar', expected: '.\\PRN:..\\bar' },
+  { input: 'AUX:/../../baz', expected: '.\\AUX:..\\..\\baz' },
+
+  { input: 'COM1:', expected: '.\\COM1:.' },
+  { input: 'COM9:', expected: '.\\COM9:.' },
+  { input: 'COM1:.\\..\\..\\foo', expected: '.\\COM1:..\\..\\foo' },
+  { input: 'LPT1:', expected: '.\\LPT1:.' },
+  { input: 'LPT9:', expected: '.\\LPT9:.' },
+  { input: 'LPT1:.\\..\\..\\foo', expected: '.\\LPT1:..\\..\\foo' },
+  { input: 'LpT5:/another/path', expected: '.\\LpT5:another\\path' },
+
+  { input: 'C:\\foo', expected: 'C:\\foo' },
+  { input: 'D:bar', expected: 'D:bar' },
+
+  { input: 'CON', expected: 'CON' },
+  { input: 'CON.TXT', expected: 'CON.TXT' },
+  { input: 'COM10:', expected: '.\\COM10:' },
+  { input: 'LPT10:', expected: '.\\LPT10:' },
+  { input: 'CONNINGTOWER:', expected: '.\\CONNINGTOWER:' },
+  { input: 'AUXILIARYDEVICE:', expected: '.\\AUXILIARYDEVICE:' },
+  { input: 'NULLED:', expected: '.\\NULLED:' },
+  { input: 'PRNINTER:', expected: '.\\PRNINTER:' },
+
+  { input: 'CON:\\..\\..\\windows\\system32', expected: '.\\CON:..\\..\\windows\\system32' },
+  { input: 'PRN:.././../etc/passwd', expected: '.\\PRN:..\\..\\etc\\passwd' },
+
+  // Test with trailing slashes
+  { input: 'CON:\\', expected: '.\\CON:.\\' },
+  { input: 'COM1:\\foo\\bar\\', expected: '.\\COM1:foo\\bar\\' },
+
+  // Test cases from original vulnerability reports or similar scenarios
+  { input: 'COM1:.\\..\\..\\foo.js', expected: '.\\COM1:..\\..\\foo.js' },
+  { input: 'LPT1:.\\..\\..\\another.txt', expected: '.\\LPT1:..\\..\\another.txt' },
+
+  // Paths with device names not at the beginning
+  { input: 'C:\\CON', expected: 'C:\\CON' },
+  { input: 'C:\\path\\to\\COM1:', expected: 'C:\\path\\to\\COM1:' },
+
+  // Device name followed by multiple colons
+  { input: 'CON::', expected: '.\\CON::' },
+  { input: 'COM1:::foo', expected: '.\\COM1:::foo' },
+
+  // Device name with mixed path separators
+  { input: 'AUX:/foo\\bar/baz', expected: '.\\AUX:foo\\bar\\baz' },
+];
+
+for (const { input, expected } of normalizeDeviceNameTests) {
+  const actual = path.win32.normalize(input);
+  assert.strictEqual(actual, expected,
+                     `path.win32.normalize(${JSON.stringify(input)}) === ${JSON.stringify(expected)}, but got ${JSON.stringify(actual)}`);
+}
+
+assert.strictEqual(path.win32.normalize('CON:foo/../bar'), '.\\CON:bar');
+
+// This should NOT be prefixed because 'c:' is treated as a drive letter.
+assert.strictEqual(path.win32.normalize('c:COM1:'), 'c:COM1:');