Bug 1377555 Part 2: Add option to Windows chromium sandbox policy to not use restricting SIDs. r=jimm

security/sandbox/chromium/sandbox/win/src/restricted_token_utils.cc

@@ -22,6 +22,7 @@ DWORD CreateRestrictedToken(TokenLevel security_level,
                             IntegrityLevel integrity_level,
                             TokenType token_type,
                             bool lockdown_default_dacl,
+                            bool use_restricting_sids,
                             base::win::ScopedHandle* token) {
   RestrictedToken restricted_token;
   restricted_token.Init(NULL);  // Initialized with the current process token
@@ -45,9 +46,12 @@ DWORD CreateRestrictedToken(TokenLevel security_level,
       deny_sids = false;
       remove_privileges = false;
 
-      unsigned err_code = restricted_token.AddRestrictingSidAllSids();
-      if (ERROR_SUCCESS != err_code)
-        return err_code;
+      if (use_restricting_sids) {
+        unsigned err_code = restricted_token.AddRestrictingSidAllSids();
+        if (ERROR_SUCCESS != err_code) {
+          return err_code;
+        }
+      }
 
       break;
     }
@@ -71,11 +75,13 @@ DWORD CreateRestrictedToken(TokenLevel security_level,
       sid_exceptions.push_back(WinInteractiveSid);
       sid_exceptions.push_back(WinAuthenticatedUserSid);
       privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
-      restricted_token.AddRestrictingSid(WinBuiltinUsersSid);
-      restricted_token.AddRestrictingSid(WinWorldSid);
-      restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
-      restricted_token.AddRestrictingSidCurrentUser();
-      restricted_token.AddRestrictingSidLogonSession();
+      if (use_restricting_sids) {
+        restricted_token.AddRestrictingSid(WinBuiltinUsersSid);
+        restricted_token.AddRestrictingSid(WinWorldSid);
+        restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
+        restricted_token.AddRestrictingSidCurrentUser();
+        restricted_token.AddRestrictingSidLogonSession();
+      }
       break;
     }
     case USER_LIMITED: {
@@ -83,27 +89,33 @@ DWORD CreateRestrictedToken(TokenLevel security_level,
       sid_exceptions.push_back(WinWorldSid);
       sid_exceptions.push_back(WinInteractiveSid);
       privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
-      restricted_token.AddRestrictingSid(WinBuiltinUsersSid);
-      restricted_token.AddRestrictingSid(WinWorldSid);
-      restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
+      if (use_restricting_sids) {
+        restricted_token.AddRestrictingSid(WinBuiltinUsersSid);
+        restricted_token.AddRestrictingSid(WinWorldSid);
+        restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
 
-      // This token has to be able to create objects in BNO.
-      // Unfortunately, on Vista+, it needs the current logon sid
-      // in the token to achieve this. You should also set the process to be
-      // low integrity level so it can't access object created by other
-      // processes.
-      restricted_token.AddRestrictingSidLogonSession();
+        // This token has to be able to create objects in BNO.
+        // Unfortunately, on Vista+, it needs the current logon sid
+        // in the token to achieve this. You should also set the process to be
+        // low integrity level so it can't access object created by other
+        // processes.
+        restricted_token.AddRestrictingSidLogonSession();
+      }
       break;
     }
     case USER_RESTRICTED: {
       privilege_exceptions.push_back(SE_CHANGE_NOTIFY_NAME);
       restricted_token.AddUserSidForDenyOnly();
-      restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
+      if (use_restricting_sids) {
+        restricted_token.AddRestrictingSid(WinRestrictedCodeSid);
+      }
       break;
     }
     case USER_LOCKDOWN: {
       restricted_token.AddUserSidForDenyOnly();
-      restricted_token.AddRestrictingSid(WinNullSid);
+      if (use_restricting_sids) {
+        restricted_token.AddRestrictingSid(WinNullSid);
+      }
       break;
     }
     default: {

security/sandbox/chromium/sandbox/win/src/restricted_token_utils.h

@@ -40,6 +40,7 @@ DWORD CreateRestrictedToken(TokenLevel security_level,
                             IntegrityLevel integrity_level,
                             TokenType token_type,
                             bool lockdown_default_dacl,
+                            bool use_restricting_sids,
                             base::win::ScopedHandle* token);
 
 // Sets the integrity label on a object handle.

security/sandbox/chromium/sandbox/win/src/sandbox_policy.h

@@ -100,6 +100,11 @@ class TargetPolicy {
   // Returns the lockdown token level.
   virtual TokenLevel GetLockdownTokenLevel() const = 0;
 
+  // Sets that we should not use restricting SIDs in the access tokens. We need
+  // to do this in some circumstances even though it weakens the sandbox.
+  // The default is to use them.
+  virtual void SetDoNotUseRestrictingSIDs() = 0;
+
   // Sets the security level of the Job Object to which the target process will
   // belong. This setting is permanent and cannot be changed once the target
   // process is spawned. The job controls the global security settings which

security/sandbox/chromium/sandbox/win/src/sandbox_policy_base.cc

@@ -183,6 +183,10 @@ TokenLevel PolicyBase::GetLockdownTokenLevel() const {
   return lockdown_level_;
 }
 
+void PolicyBase::SetDoNotUseRestrictingSIDs() {
+  use_restricting_sids_ = false;
+}
+
 ResultCode PolicyBase::SetJobLevel(JobLevel job_level, uint32_t ui_exceptions) {
   if (memory_limit_ && job_level == JOB_NONE) {
     return SBOX_ERROR_BAD_PARAMS;
@@ -437,7 +441,8 @@ ResultCode PolicyBase::MakeTokens(base::win::ScopedHandle* initial,
   // with the process and therefore with any thread that is not impersonating.
   DWORD result =
       CreateRestrictedToken(lockdown_level_, integrity_level_, PRIMARY,
-                            lockdown_default_dacl_, lockdown);
+                            lockdown_default_dacl_, use_restricting_sids_,
+                            lockdown);
   if (ERROR_SUCCESS != result)
     return SBOX_ERROR_GENERIC;
 
@@ -493,7 +498,8 @@ ResultCode PolicyBase::MakeTokens(base::win::ScopedHandle* initial,
   // what we need (before reaching main( ))
   result =
       CreateRestrictedToken(initial_level_, integrity_level_, IMPERSONATION,
-                            lockdown_default_dacl_, initial);
+                            lockdown_default_dacl_, use_restricting_sids_,
+                            initial);
   if (ERROR_SUCCESS != result)
     return SBOX_ERROR_GENERIC;
 

security/sandbox/chromium/sandbox/win/src/sandbox_policy_base.h

@@ -42,6 +42,7 @@ class PolicyBase final : public TargetPolicy {
   ResultCode SetTokenLevel(TokenLevel initial, TokenLevel lockdown) override;
   TokenLevel GetInitialTokenLevel() const override;
   TokenLevel GetLockdownTokenLevel() const override;
+  void SetDoNotUseRestrictingSIDs() final;
   ResultCode SetJobLevel(JobLevel job_level, uint32_t ui_exceptions) override;
   JobLevel GetJobLevel() const override;
   ResultCode SetJobMemoryLimit(size_t memory_limit) override;
@@ -127,6 +128,7 @@ class PolicyBase final : public TargetPolicy {
   // The user-defined global policy settings.
   TokenLevel lockdown_level_;
   TokenLevel initial_level_;
+  bool use_restricting_sids_ = true;
   JobLevel job_level_;
   uint32_t ui_exceptions_;
   size_t memory_limit_;