Add regex escaping code to Mac sandbox implementation and re-enable the utility process on OS X.

chrome/common/sandbox_mac_unittest.mm

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Cocoa/Cocoa.h>
+#include <dirent.h>
+
+extern "C" {
+#include <sandbox.h>
+}
+
+#include "base/file_util.h"
+#include "base/file_path.h"
+#include "base/multiprocess_test.h"
+#include "base/string_util.h"
+#include "base/sys_string_conversions.h"
+#include "chrome/common/sandbox_mac.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+bool QuotePlainString(const std::string& str_utf8, std::string* dst);
+bool QuoteStringForRegex(const std::string& str_utf8, std::string* dst);
+
+}  // namespace sandbox
+
+static const char* kSandboxAccessPathKey = "sandbox_dir";
+
+class MacSandboxTest : public MultiProcessTest {
+ public:
+  bool CheckSandbox(std::string directory_to_try) {
+    setenv(kSandboxAccessPathKey, directory_to_try.c_str(), 1);
+    base::ProcessHandle child_process = SpawnChild(L"mac_sandbox_path_access");
+    int code = -1;
+    if (!base::WaitForExitCode(child_process, &code)) {
+      LOG(WARNING) << "base::WaitForExitCode failed";
+      return false;
+    }
+    return code == 0;
+  }
+};
+
+TEST_F(MacSandboxTest, StringEscape) {
+  using sandbox::QuotePlainString;
+
+  const struct string_escape_test_data {
+  const char* to_escape;
+  const char* escaped;
+  } string_escape_cases[] = {
+    {"", ""},
+    {"\b\f\n\r\t\\\"", "\\b\\f\\n\\r\\t\\\\\\\""},
+    {"/'", "/'"},
+    {"sandwich", "sandwich"},
+    {"(sandwich)", "(sandwich)"},
+    {"^\u2135.\u2136$", "^\\u2135.\\u2136$"},
+  };
+
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(string_escape_cases); ++i) {
+    std::string out;
+    std::string in(string_escape_cases[i].to_escape);
+    EXPECT_TRUE(QuotePlainString(in, &out));
+    EXPECT_EQ(string_escape_cases[i].escaped, out);
+  }
+}
+
+TEST_F(MacSandboxTest, RegexEscape) {
+  using sandbox::QuoteStringForRegex;
+
+  const std::string kSandboxEscapeSuffix("(/|$)");
+  const struct regex_test_data {
+    const wchar_t *to_escape;
+    const char* escaped;
+  } regex_cases[] = {
+    {L"", ""},
+    {L"/'", "/'"},  // / & ' characters don't need escaping.
+    {L"sandwich", "sandwich"},
+    {L"(sandwich)", "\\(sandwich\\)"},
+  };
+
+  // Check that all characters whose values are smaller than 32 [1F] are
+  // rejected by the regex escaping code.
+  {
+    std::string out;
+    char fail_string[] = {31, 0};
+    char ok_string[] = {32, 0};
+    EXPECT_FALSE(QuoteStringForRegex(fail_string, &out));
+    EXPECT_TRUE(QuoteStringForRegex(ok_string, &out));
+  }
+
+  // Check that all characters whose values are larger than 126 [7E] are
+  // rejected by the regex escaping code.
+  {
+    std::string out;
+    EXPECT_TRUE(QuoteStringForRegex("}", &out));   // } == 0x7D == 125
+    EXPECT_FALSE(QuoteStringForRegex("~", &out));  // ~ == 0x7E == 126
+    EXPECT_FALSE(QuoteStringForRegex(WideToUTF8(L"^\u2135.\u2136$"), &out));
+  }
+
+  {
+    for (size_t i = 0; i < ARRAYSIZE_UNSAFE(regex_cases); ++i) {
+      std::string out;
+      std::string in = WideToUTF8(regex_cases[i].to_escape);
+      EXPECT_TRUE(QuoteStringForRegex(in, &out));
+      std::string expected("^");
+      expected.append(regex_cases[i].escaped);
+      expected.append(kSandboxEscapeSuffix);
+      EXPECT_EQ(expected, out);
+    }
+  }
+
+  {
+    std::string in_utf8("\\^.$|()[]*+?{}");
+    std::string expected;
+    expected.push_back('^');
+    for (size_t i = 0; i < in_utf8.length(); ++i) {
+      expected.push_back('\\');
+      expected.push_back(in_utf8[i]);
+    }
+    expected.append(kSandboxEscapeSuffix);
+
+    std::string out;
+    EXPECT_TRUE(QuoteStringForRegex(in_utf8, &out));
+    EXPECT_EQ(expected, out);
+
+  }
+}
+
+// A class to handle auto-deleting a directory.
+class ScopedDirectoryDelete {
+ public:
+  inline void operator()(FilePath* x) const {
+    if (x) {
+      file_util::Delete(*x, true);
+    }
+  }
+};
+
+typedef scoped_ptr_malloc<FilePath, ScopedDirectoryDelete> ScopedDirectory;
+
+TEST_F(MacSandboxTest, SandboxAccess) {
+  FilePath tmp_dir;
+  ASSERT_TRUE(file_util::CreateNewTempDirectory("", &tmp_dir));
+  // This step is important on OS X since the sandbox only understands "real"
+  // paths and the paths CreateNewTempDirectory() returns are empirically in
+  // /var which is a symlink to /private/var .
+  ASSERT_TRUE(file_util::AbsolutePath(&tmp_dir));
+  ScopedDirectory cleanup(&tmp_dir);
+
+  const char* sandbox_dir_cases[] = {
+    "simple_dir_name",
+    "^hello++ $",       // Regex.
+    "\\^.$|()[]*+?{}",  // All regex characters.
+  };
+
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(sandbox_dir_cases); ++i) {
+    const char* sandbox_dir_name = sandbox_dir_cases[i];
+    FilePath sandbox_dir = tmp_dir.Append(sandbox_dir_name);
+    ASSERT_TRUE(file_util::CreateDirectory(sandbox_dir));
+    ScopedDirectory cleanup_sandbox(&sandbox_dir);
+    EXPECT_TRUE(CheckSandbox(sandbox_dir.value()));
+  }
+}
+
+MULTIPROCESS_TEST_MAIN(mac_sandbox_path_access) {
+  char *sandbox_allowed_dir = getenv(kSandboxAccessPathKey);
+  if (!sandbox_allowed_dir)
+    return -1;
+
+  // Build up a sandbox profile that only allows access to DIR_TO_ALLOW_ACCESS.
+  NSString *sandbox_profile =
+      @"(version 1)" \
+      "(deny default)" \
+      "(allow signal (target self))" \
+      "(allow sysctl-read)" \
+      "(allow file-read-metadata)" \
+      "(allow file-read* file-write* (regex #\"DIR_TO_ALLOW_ACCESS\"))";
+
+  std::string allowed_dir(sandbox_allowed_dir);
+  std::string allowed_dir_escaped;
+  if (!sandbox::QuoteStringForRegex(allowed_dir, &allowed_dir_escaped)) {
+    LOG(ERROR) << "Regex string quoting failed " << allowed_dir;
+    return -1;
+  }
+  NSString* allowed_dir_escaped_ns = base::SysUTF8ToNSString(
+        allowed_dir_escaped.c_str());
+  sandbox_profile = [sandbox_profile
+      stringByReplacingOccurrencesOfString:@"DIR_TO_ALLOW_ACCESS"
+                                withString:allowed_dir_escaped_ns];
+  // Enable Sandbox.
+  char* error_buff = NULL;
+  int error = sandbox_init([sandbox_profile UTF8String], 0, &error_buff);
+  if (error == -1) {
+    LOG(ERROR) << "Failed to Initialize Sandbox: " << error_buff;
+    return -1;
+  }
+  sandbox_free_error(error_buff);
+
+  // Test Sandbox.
+
+  // We should be able to list the contents of the sandboxed directory.
+  DIR *file_list = NULL;
+  file_list = opendir(sandbox_allowed_dir);
+  if (!file_list) {
+    PLOG(ERROR) << "Sandbox overly restrictive: call to opendir("
+                << sandbox_allowed_dir
+                << ") failed";
+    return -1;
+  }
+  closedir(file_list);
+
+  // Test restrictions on accessing files.
+  FilePath allowed_dir_path(sandbox_allowed_dir);
+  FilePath allowed_file = allowed_dir_path.Append("ok_to_write");
+  FilePath denied_file1 =  allowed_dir_path.DirName().Append("cant_access");
+
+  // Try to write a file who's name has the same prefix as the directory we
+  // allow access to.
+  FilePath basename = allowed_dir_path.BaseName();
+  std::string tricky_filename = basename.value() + "123";
+  FilePath denied_file2 =  allowed_dir_path.DirName().Append(tricky_filename);
+
+  if (open(allowed_file.value().c_str(), O_WRONLY | O_CREAT) <= 0) {
+    PLOG(ERROR) << "Sandbox overly restrictive: failed to write ("
+                << allowed_file.value()
+                << ")";
+    return -1;
+  }
+
+  if (open(denied_file1.value().c_str(), O_WRONLY | O_CREAT) > 0) {
+    PLOG(ERROR) << "Sandbox breach: was able to write ("
+                << denied_file1.value()
+                << ")";
+    return -1;
+  }
+
+  if (open(denied_file2.value().c_str(), O_WRONLY | O_CREAT) > 0) {
+    PLOG(ERROR) << "Sandbox breach: was able to write ("
+                << denied_file2.value()
+                << ")";
+    return -1;
+  }
+
+  return 0;
+}