From 4971756d8d9b7b9f1954a1357348f3dd2b9d4a68 Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Mon, 2 Dec 2024 20:19:02 -0800
Subject: [PATCH] Internal change.

PiperOrigin-RevId: 702177156
---
 pkg/sentry/syscalls/linux/sys_file.go |  8 ++++----
 test/syscalls/linux/BUILD             |  1 +
 test/syscalls/linux/access.cc         | 26 ++++++++++++++++++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go
index 3d8665726..e78a01acc 100644
--- a/pkg/sentry/syscalls/linux/sys_file.go
+++ b/pkg/sentry/syscalls/linux/sys_file.go
@@ -127,7 +127,7 @@ func openat(t *kernel.Task, dirfd int32, pathAddr hostarch.Addr, flags uint32, m
 // Access implements Linux syscall access(2).
 func Access(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	addr := args[0].Pointer()
-	mode := args[1].ModeT()
+	mode := args[1].Uint()
 
 	return 0, nil, accessAt(t, linux.AT_FDCWD, addr, mode, 0 /* flags */)
 }
@@ -136,7 +136,7 @@ func Access(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr,
 func Faccessat(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	dirfd := args[0].Int()
 	addr := args[1].Pointer()
-	mode := args[2].ModeT()
+	mode := args[2].Uint()
 
 	return 0, nil, accessAt(t, dirfd, addr, mode, 0 /* flags */)
 }
@@ -145,13 +145,13 @@ func Faccessat(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintp
 func Faccessat2(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	dirfd := args[0].Int()
 	addr := args[1].Pointer()
-	mode := args[2].ModeT()
+	mode := args[2].Uint()
 	flags := args[3].Int()
 
 	return 0, nil, accessAt(t, dirfd, addr, mode, flags)
 }
 
-func accessAt(t *kernel.Task, dirfd int32, pathAddr hostarch.Addr, mode uint, flags int32) error {
+func accessAt(t *kernel.Task, dirfd int32, pathAddr hostarch.Addr, mode uint32, flags int32) error {
 	const rOK = 4
 	const wOK = 2
 	const xOK = 1
diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 771b590ce..7ad68bd79 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -253,6 +253,7 @@ cc_binary(
         "//test/util:temp_path",
         "//test/util:test_main",
         "//test/util:test_util",
+        "@com_google_absl//absl/strings:str_format",
     ],
 )
 
diff --git a/test/syscalls/linux/access.cc b/test/syscalls/linux/access.cc
index fef94d64e..dc98327e5 100644
--- a/test/syscalls/linux/access.cc
+++ b/test/syscalls/linux/access.cc
@@ -20,7 +20,10 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <set>
+
 #include "gtest/gtest.h"
+#include "absl/strings/str_format.h"
 #include "test/util/capability_util.h"
 #include "test/util/fs_util.h"
 #include "test/util/temp_path.h"
@@ -113,6 +116,29 @@ TEST_F(AccessTest, InvalidMode) {
               SyscallFailsWithErrno(EINVAL));
 }
 
+TEST_F(AccessTest, InvalidModeRoot) {
+  EXPECT_THAT(access("/", R_OK | 0x8000'0000), SyscallFailsWithErrno(EINVAL));
+}
+
+TEST_F(AccessTest, InvalidModes) {
+  // The only valid modes are:
+  // * F_OK
+  // * bitwise or combinations of R_OK, W_OK, and X_OK
+  std::set<int> valid_modes = {
+      F_OK,        R_OK,        W_OK,        X_OK,
+      R_OK | W_OK, R_OK | X_OK, W_OK | X_OK, R_OK | W_OK | X_OK};
+  for (size_t i = 0; i < 32; i++) {
+    int mode_bit = 1 << i;
+    for (int valid_mode : valid_modes) {
+      int mode = valid_mode | mode_bit;
+      if (valid_modes.find(mode) != valid_modes.end()) continue;
+      SCOPED_TRACE(absl::StrFormat("mode=%08x", mode));
+      EXPECT_THAT(access(relfile_.c_str(), mode),
+                  SyscallFailsWithErrno(EINVAL));
+    }
+  }
+}
+
 TEST_F(AccessTest, NoPerms) {
   // Drop capabilities that allow us to override permissions. We must drop
   // PERMITTED because access() checks those instead of EFFECTIVE.