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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #import <Cocoa/Cocoa.h>
      6 #include <dirent.h>
      7 
      8 extern "C" {
      9 #include <sandbox.h>
     10 }
     11 
     12 #include "base/file_util.h"
     13 #include "base/files/file_path.h"
     14 #include "base/process/kill.h"
     15 #include "base/strings/sys_string_conversions.h"
     16 #include "base/strings/utf_string_conversions.h"
     17 #include "base/test/multiprocess_test.h"
     18 #include "content/common/sandbox_mac.h"
     19 #include "testing/gtest/include/gtest/gtest.h"
     20 #include "testing/multiprocess_func_list.h"
     21 
     22 namespace {
     23 
     24 static const char* kSandboxAccessPathKey = "sandbox_dir";
     25 static const char* kDeniedSuffix = "_denied";
     26 
     27 }  // namespace
     28 
     29 // Tests need to be in the same namespace as the Sandbox class to be useable
     30 // with FRIEND_TEST() declaration.
     31 namespace content {
     32 
     33 class MacDirAccessSandboxTest : public base::MultiProcessTest {
     34  public:
     35   bool CheckSandbox(const std::string& directory_to_try) {
     36     setenv(kSandboxAccessPathKey, directory_to_try.c_str(), 1);
     37     base::ProcessHandle child_process = SpawnChild("mac_sandbox_path_access");
     38     if (child_process == base::kNullProcessHandle) {
     39       LOG(WARNING) << "SpawnChild failed";
     40       return false;
     41     }
     42     int code = -1;
     43     if (!base::WaitForExitCode(child_process, &code)) {
     44       LOG(WARNING) << "base::WaitForExitCode failed";
     45       return false;
     46     }
     47     return code == 0;
     48   }
     49 };
     50 
     51 TEST_F(MacDirAccessSandboxTest, StringEscape) {
     52   const struct string_escape_test_data {
     53   const char* to_escape;
     54   const char* escaped;
     55   } string_escape_cases[] = {
     56     {"", ""},
     57     {"\b\f\n\r\t\\\"", "\\b\\f\\n\\r\\t\\\\\\\""},
     58     {"/'", "/'"},
     59     {"sandwich", "sandwich"},
     60     {"(sandwich)", "(sandwich)"},
     61     {"^\u2135.\u2136$", "^\\u2135.\\u2136$"},
     62   };
     63 
     64   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(string_escape_cases); ++i) {
     65     std::string out;
     66     std::string in(string_escape_cases[i].to_escape);
     67     EXPECT_TRUE(Sandbox::QuotePlainString(in, &out));
     68     EXPECT_EQ(string_escape_cases[i].escaped, out);
     69   }
     70 }
     71 
     72 TEST_F(MacDirAccessSandboxTest, RegexEscape) {
     73   const std::string kSandboxEscapeSuffix("(/|$)");
     74   const struct regex_test_data {
     75     const wchar_t *to_escape;
     76     const char* escaped;
     77   } regex_cases[] = {
     78     {L"", ""},
     79     {L"/'", "/'"},  // / & ' characters don't need escaping.
     80     {L"sandwich", "sandwich"},
     81     {L"(sandwich)", "\\(sandwich\\)"},
     82   };
     83 
     84   // Check that all characters whose values are smaller than 32 [1F] are
     85   // rejected by the regex escaping code.
     86   {
     87     std::string out;
     88     char fail_string[] = {31, 0};
     89     char ok_string[] = {32, 0};
     90     EXPECT_FALSE(Sandbox::QuoteStringForRegex(fail_string, &out));
     91     EXPECT_TRUE(Sandbox::QuoteStringForRegex(ok_string, &out));
     92   }
     93 
     94   // Check that all characters whose values are larger than 126 [7E] are
     95   // rejected by the regex escaping code.
     96   {
     97     std::string out;
     98     EXPECT_TRUE(Sandbox::QuoteStringForRegex("}", &out));   // } == 0x7D == 125
     99     EXPECT_FALSE(Sandbox::QuoteStringForRegex("~", &out));  // ~ == 0x7E == 126
    100     EXPECT_FALSE(
    101         Sandbox::QuoteStringForRegex(base::WideToUTF8(L"^\u2135.\u2136$"),
    102                                      &out));
    103   }
    104 
    105   {
    106     for (size_t i = 0; i < ARRAYSIZE_UNSAFE(regex_cases); ++i) {
    107       std::string out;
    108       std::string in = base::WideToUTF8(regex_cases[i].to_escape);
    109       EXPECT_TRUE(Sandbox::QuoteStringForRegex(in, &out));
    110       std::string expected("^");
    111       expected.append(regex_cases[i].escaped);
    112       expected.append(kSandboxEscapeSuffix);
    113       EXPECT_EQ(expected, out);
    114     }
    115   }
    116 
    117   {
    118     std::string in_utf8("\\^.$|()[]*+?{}");
    119     std::string expected;
    120     expected.push_back('^');
    121     for (size_t i = 0; i < in_utf8.length(); ++i) {
    122       expected.push_back('\\');
    123       expected.push_back(in_utf8[i]);
    124     }
    125     expected.append(kSandboxEscapeSuffix);
    126 
    127     std::string out;
    128     EXPECT_TRUE(Sandbox::QuoteStringForRegex(in_utf8, &out));
    129     EXPECT_EQ(expected, out);
    130 
    131   }
    132 }
    133 
    134 // A class to handle auto-deleting a directory.
    135 struct ScopedDirectoryDelete {
    136   inline void operator()(base::FilePath* x) const {
    137     if (x)
    138       base::DeleteFile(*x, true);
    139   }
    140 };
    141 
    142 typedef scoped_ptr<base::FilePath, ScopedDirectoryDelete> ScopedDirectory;
    143 
    144 TEST_F(MacDirAccessSandboxTest, SandboxAccess) {
    145   using base::CreateDirectory;
    146 
    147   base::FilePath tmp_dir;
    148   ASSERT_TRUE(base::CreateNewTempDirectory(base::FilePath::StringType(),
    149                                            &tmp_dir));
    150   // This step is important on OS X since the sandbox only understands "real"
    151   // paths and the paths CreateNewTempDirectory() returns are empirically in
    152   // /var which is a symlink to /private/var .
    153   tmp_dir = Sandbox::GetCanonicalSandboxPath(tmp_dir);
    154   ScopedDirectory cleanup(&tmp_dir);
    155 
    156   const char* sandbox_dir_cases[] = {
    157     "simple_dir_name",
    158     "^hello++ $",       // Regex.
    159     "\\^.$|()[]*+?{}",  // All regex characters.
    160   };
    161 
    162   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(sandbox_dir_cases); ++i) {
    163     const char* sandbox_dir_name = sandbox_dir_cases[i];
    164     base::FilePath sandbox_dir = tmp_dir.Append(sandbox_dir_name);
    165     ASSERT_TRUE(CreateDirectory(sandbox_dir));
    166     ScopedDirectory cleanup_sandbox(&sandbox_dir);
    167 
    168     // Create a sibling directory of the sandbox dir, whose name has sandbox dir
    169     // as a substring but to which access is denied.
    170     std::string sibling_sandbox_dir_name_denied =
    171         std::string(sandbox_dir_cases[i]) + kDeniedSuffix;
    172     base::FilePath sibling_sandbox_dir = tmp_dir.Append(
    173                                       sibling_sandbox_dir_name_denied.c_str());
    174     ASSERT_TRUE(CreateDirectory(sibling_sandbox_dir));
    175     ScopedDirectory cleanup_sandbox_sibling(&sibling_sandbox_dir);
    176 
    177     EXPECT_TRUE(CheckSandbox(sandbox_dir.value()));
    178   }
    179 }
    180 
    181 MULTIPROCESS_TEST_MAIN(mac_sandbox_path_access) {
    182   char *sandbox_allowed_dir = getenv(kSandboxAccessPathKey);
    183   if (!sandbox_allowed_dir)
    184     return -1;
    185 
    186   // Build up a sandbox profile that only allows access to a single directory.
    187   NSString *sandbox_profile =
    188       @"(version 1)" \
    189       "(deny default)" \
    190       "(allow signal (target self))" \
    191       "(allow sysctl-read)" \
    192       ";ENABLE_DIRECTORY_ACCESS";
    193 
    194   std::string allowed_dir(sandbox_allowed_dir);
    195   Sandbox::SandboxVariableSubstitions substitutions;
    196   NSString* allow_dir_sandbox_code =
    197       Sandbox::BuildAllowDirectoryAccessSandboxString(
    198           base::FilePath(sandbox_allowed_dir),
    199           &substitutions);
    200   sandbox_profile = [sandbox_profile
    201       stringByReplacingOccurrencesOfString:@";ENABLE_DIRECTORY_ACCESS"
    202                                 withString:allow_dir_sandbox_code];
    203 
    204   std::string final_sandbox_profile_str;
    205   if (!Sandbox::PostProcessSandboxProfile(sandbox_profile,
    206                                           [NSArray array],
    207                                           substitutions,
    208                                           &final_sandbox_profile_str)) {
    209     LOG(ERROR) << "Call to PostProcessSandboxProfile() failed";
    210     return -1;
    211   }
    212 
    213   // Enable Sandbox.
    214   char* error_buff = NULL;
    215   int error = sandbox_init(final_sandbox_profile_str.c_str(), 0, &error_buff);
    216   if (error == -1) {
    217     LOG(ERROR) << "Failed to Initialize Sandbox: " << error_buff;
    218     return -1;
    219   }
    220   sandbox_free_error(error_buff);
    221 
    222   // Test Sandbox.
    223 
    224   // We should be able to list the contents of the sandboxed directory.
    225   DIR *file_list = NULL;
    226   file_list = opendir(sandbox_allowed_dir);
    227   if (!file_list) {
    228     PLOG(ERROR) << "Sandbox overly restrictive: call to opendir("
    229                 << sandbox_allowed_dir
    230                 << ") failed";
    231     return -1;
    232   }
    233   closedir(file_list);
    234 
    235   // Test restrictions on accessing files.
    236   base::FilePath allowed_dir_path(sandbox_allowed_dir);
    237   base::FilePath allowed_file = allowed_dir_path.Append("ok_to_write");
    238   base::FilePath denied_file1 =
    239       allowed_dir_path.DirName().Append("cant_access");
    240 
    241   // Try to write a file who's name has the same prefix as the directory we
    242   // allow access to.
    243   base::FilePath basename = allowed_dir_path.BaseName();
    244   base::FilePath allowed_parent_dir = allowed_dir_path.DirName();
    245   std::string tricky_filename = basename.value() + "123";
    246   base::FilePath denied_file2 =  allowed_parent_dir.Append(tricky_filename);
    247 
    248   if (open(allowed_file.value().c_str(), O_WRONLY | O_CREAT) <= 0) {
    249     PLOG(ERROR) << "Sandbox overly restrictive: failed to write ("
    250                 << allowed_file.value()
    251                 << ")";
    252     return -1;
    253   }
    254 
    255   // Test that we deny access to a sibling of the sandboxed directory whose
    256   // name has the sandboxed directory name as a substring. e.g. if the sandbox
    257   // directory is /foo/baz then test /foo/baz_denied.
    258   {
    259     struct stat tmp_stat_info;
    260     std::string denied_sibling =
    261         std::string(sandbox_allowed_dir) + kDeniedSuffix;
    262     if (stat(denied_sibling.c_str(), &tmp_stat_info) > 0) {
    263       PLOG(ERROR) << "Sandbox breach: was able to stat ("
    264                   << denied_sibling.c_str()
    265                   << ")";
    266       return -1;
    267     }
    268   }
    269 
    270   // Test that we can stat parent directories of the "allowed" directory.
    271   {
    272     struct stat tmp_stat_info;
    273     if (stat(allowed_parent_dir.value().c_str(), &tmp_stat_info) != 0) {
    274       PLOG(ERROR) << "Sandbox overly restrictive: unable to stat ("
    275                   << allowed_parent_dir.value()
    276                   << ")";
    277       return -1;
    278     }
    279   }
    280 
    281   // Test that we can't stat files outside the "allowed" directory.
    282   {
    283     struct stat tmp_stat_info;
    284     if (stat(denied_file1.value().c_str(), &tmp_stat_info) > 0) {
    285       PLOG(ERROR) << "Sandbox breach: was able to stat ("
    286                   << denied_file1.value()
    287                   << ")";
    288       return -1;
    289     }
    290   }
    291 
    292   if (open(denied_file1.value().c_str(), O_WRONLY | O_CREAT) > 0) {
    293     PLOG(ERROR) << "Sandbox breach: was able to write ("
    294                 << denied_file1.value()
    295                 << ")";
    296     return -1;
    297   }
    298 
    299   if (open(denied_file2.value().c_str(), O_WRONLY | O_CREAT) > 0) {
    300     PLOG(ERROR) << "Sandbox breach: was able to write ("
    301                 << denied_file2.value()
    302                 << ")";
    303     return -1;
    304   }
    305 
    306   return 0;
    307 }
    308 
    309 }  // namespace content
    310