fix(node:fs): set allow above root (#16814)

Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>

src/bun.js/node/types.zig

@@ -932,15 +932,15 @@ pub const PathLike = union(enum) {
         return buf[0..sliced.len :0];
     }
 
-    pub inline fn sliceZ(this: PathLike, buf: *bun.PathBuffer) [:0]const u8 {
+    pub fn sliceZ(this: PathLike, buf: *bun.PathBuffer) callconv(bun.callconv_inline) [:0]const u8 {
         return sliceZWithForceCopy(this, buf, false);
     }
 
-    pub inline fn sliceW(this: PathLike, buf: *bun.WPathBuffer) [:0]const u16 {
+    pub fn sliceW(this: PathLike, buf: *bun.WPathBuffer) callconv(bun.callconv_inline) [:0]const u16 {
         return strings.toWPath(buf, this.slice());
     }
 
-    pub inline fn osPath(this: PathLike, buf: *bun.OSPathBuffer) bun.OSPathSliceZ {
+    pub fn osPath(this: PathLike, buf: *bun.OSPathBuffer) callconv(bun.callconv_inline) bun.OSPathSliceZ {
         if (comptime Environment.isWindows) {
             return sliceW(this, buf);
         }
@@ -948,7 +948,7 @@ pub const PathLike = union(enum) {
         return sliceZWithForceCopy(this, buf, false);
     }
 
-    pub inline fn osPathKernel32(this: PathLike, buf: *bun.PathBuffer) bun.OSPathSliceZ {
+    pub fn osPathKernel32(this: PathLike, buf: *bun.PathBuffer) callconv(bun.callconv_inline) bun.OSPathSliceZ {
         if (comptime Environment.isWindows) {
             const s = this.slice();
             const b = bun.PathBufferPool.get();
@@ -958,7 +958,7 @@ pub const PathLike = union(enum) {
                 const normal = path_handler.normalizeBuf(resolve, b, .windows);
                 return strings.toKernel32Path(@alignCast(std.mem.bytesAsSlice(u16, buf)), normal);
             }
-            const normal = path_handler.normalizeBuf(s, b, .windows);
+            const normal = path_handler.normalizeStringBuf(s, b, true, .windows, false);
             return strings.toKernel32Path(@alignCast(std.mem.bytesAsSlice(u16, buf)), normal);
         }
 

test/js/node/fs/fs.test.ts

@@ -42,7 +42,7 @@ import fs, {
   writevSync,
 } from "node:fs";
 import * as os from "node:os";
-import { dirname, relative, resolve } from "node:path";
+import path, { dirname, relative, resolve } from "node:path";
 import { promisify } from "node:util";
 
 import _promises, { type FileHandle } from "node:fs/promises";
@@ -3603,3 +3603,46 @@ it("fs.Stat.atime reflects date matching Node.js behavior", () => {
     expect(stats.atime).toEqual(new Date(0));
   }
 });
+
+describe('kernel32 long path conversion does not mangle "../../path" into "path"', () => {
+  const tmp1 = tempDirWithFiles("longpath", {
+    "a/b/config": "true",
+  });
+  const tmp2 = tempDirWithFiles("longpath", {
+    "a/b/hello": "true",
+    "config": "true",
+  });
+  const workingDir1 = path.join(tmp1, "a/b");
+  const workingDir2 = path.join(tmp2, "a/b");
+  const nonExistTests = [
+    ["existsSync", 'assert.strictEqual(fs.existsSync("../../config"), false)'],
+    ["accessSync", 'assert.throws(() => fs.accessSync("../../config"), { code: "ENOENT" })'],
+  ];
+  const existTests = [
+    ["existsSync", 'assert.strictEqual(fs.existsSync("../../config"), true)'],
+    ["accessSync", 'assert.strictEqual(fs.accessSync("../../config"), null)'],
+  ];
+
+  for (const [name, code] of nonExistTests) {
+    it(`${name} (not existing)`, () => {
+      const { success } = spawnSync({
+        cmd: [bunExe(), "-e", code],
+        cwd: workingDir1,
+        stdio: ["ignore", "inherit", "inherit"],
+        env: bunEnv,
+      });
+      expect(success).toBeTrue();
+    });
+  }
+  for (const [name, code] of existTests) {
+    it(`${name} (existing)`, () => {
+      const { success } = spawnSync({
+        cmd: [bunExe(), "-e", code],
+        cwd: workingDir2,
+        stdio: ["ignore", "inherit", "inherit"],
+        env: bunEnv,
+      });
+      expect(success).toBeTrue();
+    });
+  }
+});