Refactor OS X sandbox processing and audit sandbox files

content/common/sandbox_mac.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_COMMON_SANDBOX_MAC_H_
 #define CONTENT_COMMON_SANDBOX_MAC_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/gtest_prod_util.h"
 #include "content/common/content_export.h"
 #include "content/public/common/sandbox_type_mac.h"
 
 namespace base {
 class FilePath;
 }
 
 #if __OBJC__
 @class NSArray;
 @class NSString;
 #else
 class NSArray;
 class NSString;
 #endif
 
 namespace content {
 
-// Class representing a substring of the sandbox profile tagged with its type.
-class SandboxSubstring {
+// This class wraps the C-style sandbox APIs in a class to
+// ensure proper initialization and cleanup

[Robert Sesek, 2015/06/16 23:52:40]

nit: Comments should have proper punctuation. Also, you can wrap this a little
more towards the 80 column limit. Apply here and throughout the entire CL (I
didn't mark it anywhere else).

[Greg K, 2015/06/18 20:45:18]

Done.

+class CONTENT_EXPORT SandboxCompiler {

[Robert Sesek, 2015/06/16 23:52:40]

Potential future TODO: Move this to //sandbox/mac and name it
sandbox::ProfileCompiler.

[Greg K, 2015/06/18 20:45:18]

Acknowledged.

  public:
-  enum SandboxSubstringType {
-    PLAIN,    // Just a plain string, no escaping necessary.
-    LITERAL,  // Escape for use in (literal ...) expression.
-    REGEX,    // Escape for use in (regex ...) expression.
-  };
-
-  SandboxSubstring() {}
-
-  explicit SandboxSubstring(const std::string& value)
-      : value_(value),
-        type_(PLAIN) {}
-
-  SandboxSubstring(const std::string& value, SandboxSubstringType type)
-      : value_(value),
-        type_(type) {}
-
-  const std::string& value() { return value_; }
-  SandboxSubstringType type() { return type_; }
+  // Explicit out-of-line constructor

[Robert Sesek, 2015/06/16 23:52:40]

nit: remove, and line 36. This should be obvious to the reader.

[Greg K, 2015/06/18 20:45:18]

Done.

+  explicit SandboxCompiler(const std::string& profile_str);
+  // Explicit out-of-line destructor
+  ~SandboxCompiler();
+  // Initialize the sandbox parameters

[Robert Sesek, 2015/06/16 23:52:40]

When does this method need to be called? Does this need to be called before
anything else?

[Greg K, 2015/06/18 20:45:18]

Acknowledged.

+  bool Init();

[Robert Sesek, 2015/06/16 23:52:40]

nit: Place blank lines after each of these methods.

[Robert Sesek, 2015/06/16 23:52:40]

Potential idea: Remove Init() entirely, and wait to construct |params_| until
CompileAndApplyProfile. Store all the values (including duplicate copies of
"TRUE" and "FALSE", yes), in |strings_|. It makes the API a little cleaner at
the cost of a little more memory. Thoughts?

[Greg K, 2015/06/18 20:45:17]

Done.

[Greg K, 2015/06/18 20:45:18]

Done.

+  // Inserts a boolean into the parameters key/value list
+  void InsertBooleanParam(const std::string& key, bool value);
+  // Inserts a string into the parameters key/value list
+  void InsertStringParam(const std::string& key, const std::string& value);
+  // Compile and apply the profile, returns 0 on success
+  int CompileAndApplyProfile(std::string* error);
 
  private:
-  std::string value_;
-  SandboxSubstringType type_;
+  // Ensure that the C++ strings are not destroyed while the

[Robert Sesek, 2015/06/16 23:52:40]

"Storage for the string parameters that are used in the profile."

[Greg K, 2015/06/18 20:45:18]

Done.

+  // parameters vector holds a pointer to their c_str()
+  std::vector<std::string> strings_;
+  void* params_;

[Robert Sesek, 2015/06/16 23:52:40]

Document these two members.

[Greg K, 2015/06/18 20:45:18]

Done.

+  void* profile_;
+  const std::string profile_str_;
+
+  DISALLOW_COPY_AND_ASSIGN(SandboxCompiler);
 };
 
 class CONTENT_EXPORT Sandbox {
  public:
-  // A map of variable name -> string to substitute in its place.
-  typedef base::hash_map<std::string, SandboxSubstring>
-      SandboxVariableSubstitions;
 
   // Warm up System APIs that empirically need to be accessed before the
   // sandbox is turned on. |sandbox_type| is the type of sandbox to warm up.
   // Valid |sandbox_type| values are defined by the enum SandboxType, or can be
   // defined by the embedder via
   // ContentClient::GetSandboxProfileForProcessType().
   static void SandboxWarmup(int sandbox_type);
 
   // Turns on the OS X sandbox for this process.
   // |sandbox_type| - type of Sandbox to use. See SandboxWarmup() for legal
   // values.
   // |allowed_dir| - directory to allow access to, currently the only sandbox
   // profile that supports this is SANDBOX_TYPE_UTILITY .
   //
   // Returns true on success, false if an error occurred enabling the sandbox.
   static bool EnableSandbox(int sandbox_type,
                             const base::FilePath& allowed_dir);
 
   // Returns true if the sandbox has been enabled for the current process.
   static bool SandboxIsCurrentlyActive();
 
-  // Exposed for testing purposes, used by an accessory function of our tests
-  // so we can't use FRIEND_TEST.
-
-  // Build the Sandbox command necessary to allow access to a named directory
-  // indicated by |allowed_dir|.
-  // Returns a string containing the sandbox profile commands necessary to allow
-  // access to that directory or nil if an error occured.
-
-  // The header comment for PostProcessSandboxProfile() explains how variable
-  // substition works in sandbox templates.
-  // The returned string contains embedded variables. The function fills in
-  // |substitutions| to contain the values for these variables.
-  static NSString* BuildAllowDirectoryAccessSandboxString(
-                       const base::FilePath& allowed_dir,
-                       SandboxVariableSubstitions* substitutions);
-
-  // Assemble the final sandbox profile from a template by removing comments
-  // and substituting variables.
-  //
-  // |sandbox_template| is a string which contains 2 entitites to operate on:
-  //
-  // - Comments - The sandbox comment syntax is used to make the OS sandbox
-  // optionally ignore commands it doesn't support. e.g.
-  // ;10.6_ONLY (foo)
-  // Where (foo) is some command that is only supported on OS X 10.6.
-  // The ;10.6_ONLY comment can then be removed from the template to enable
-  // (foo) as appropriate.
-  //
-  // - Variables - denoted by @variable_name@ .  These are defined in the
-  // sandbox template in cases where another string needs to be substituted at
-  // runtime. e.g. @HOMEDIR_AS_LITERAL@ is substituted at runtime for the user's
-  // home directory escaped appropriately for a (literal ...) expression.
-  //
-  // |comments_to_remove| is a list of NSStrings containing the comments to
-  // remove.
-  // |substitutions| is a hash of "variable name" -> "string to substitute".
-  // Where the replacement string is tagged with information on how it is to be
-  // escaped e.g. used as part of a regex string or a literal.
-  //
-  // On output |final_sandbox_profile_str| contains the final sandbox profile.
-  // Returns true on success, false otherwise.
-  static bool PostProcessSandboxProfile(
-                  NSString* in_sandbox_data,
-                  NSArray* comments_to_remove,
-                  SandboxVariableSubstitions& substitutions,
-                  std::string *final_sandbox_profile_str);
-
- private:
-  // Returns an (allow file-read-metadata) rule for |allowed_path| and all its
-  // parent directories.
-  static NSString* AllowMetadataForPath(const base::FilePath& allowed_path);
-
   // Escape |src_utf8| for use in a plain string variable in a sandbox
   // configuraton file.  On return |dst| is set to the quoted output.
   // Returns: true on success, false otherwise.
   static bool QuotePlainString(const std::string& src_utf8, std::string* dst);
 
   // Escape |str_utf8| for use in a regex literal in a sandbox
   // configuraton file.  On return |dst| is set to the utf-8 encoded quoted
   // output.
   //
   // The implementation of this function is based on empirical testing of the
   // OS X sandbox on 10.5.8 & 10.6.2 which is undocumented and subject to
   // change.
   //
   // Note: If str_utf8 contains any characters < 32 || >125 then the function
   // fails and false is returned.
   //
   // Returns: true on success, false otherwise.
   static bool QuoteStringForRegex(const std::string& str_utf8,
                                   std::string* dst);
 
+ private:
   // Convert provided path into a "canonical" path matching what the Sandbox
   // expects i.e. one without symlinks.
   // This path is not necessarily unique e.g. in the face of hardlinks.
   static base::FilePath GetCanonicalSandboxPath(const base::FilePath& path);
 
   FRIEND_TEST_ALL_PREFIXES(MacDirAccessSandboxTest, StringEscape);
   FRIEND_TEST_ALL_PREFIXES(MacDirAccessSandboxTest, RegexEscape);
   FRIEND_TEST_ALL_PREFIXES(MacDirAccessSandboxTest, SandboxAccess);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sandbox);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_SANDBOX_MAC_H_