linux: enable seccomp sandbox by default

chrome/browser/zygote_host_linux.cc

Index: chrome/browser/zygote_host_linux.cc
diff --git a/chrome/browser/zygote_host_linux.cc b/chrome/browser/zygote_host_linux.cc
index 3b6a1608e5419481c303578096dec1e15d016de9..aa5d8caa9a4980626f2eed3d7f77c2782480012c 100644
--- a/chrome/browser/zygote_host_linux.cc
+++ b/chrome/browser/zygote_host_linux.cc
@@ -24,29 +24,6 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/process_watcher.h"
 
-#include "sandbox/linux/suid/suid_unsafe_environment_variables.h"
-
-static void SaveSUIDUnsafeEnvironmentVariables() {
-  // The ELF loader will clear many environment variables so we save them to
-  // different names here so that the SUID sandbox can resolve them for the
-  // renderer.
-
-  for (unsigned i = 0; kSUIDUnsafeEnvironmentVariables[i]; ++i) {
-    const char* const envvar = kSUIDUnsafeEnvironmentVariables[i];
-    char* const saved_envvar = SandboxSavedEnvironmentVariable(envvar);
-    if (!saved_envvar)
-      continue;
-
-    const char* const value = getenv(envvar);
-    if (value)
-      setenv(saved_envvar, value, 1 /* overwrite */);
-    else
-      unsetenv(saved_envvar);
-
-    free(saved_envvar);
-  }
-}
-
 ZygoteHost::ZygoteHost()
     : pid_(-1),
       init_(false),
@@ -97,29 +74,11 @@ void ZygoteHost::Init(const std::string& sandbox_cmd) {
                                    browser_command_line.GetSwitchValueASCII(
                                        switches::kEnableLogging));
   }
-  if (browser_command_line.HasSwitch(switches::kEnableSeccompSandbox)) {
-    cmd_line.AppendSwitch(switches::kEnableSeccompSandbox);
+  if (browser_command_line.HasSwitch(switches::kDisableSeccompSandbox)) {
+    cmd_line.AppendSwitch(switches::kDisableSeccompSandbox);
   }
 
   sandbox_binary_ = sandbox_cmd.c_str();
-  struct stat st;
-
-  if (!sandbox_cmd.empty() && stat(sandbox_binary_.c_str(), &st) == 0) {
-    if (access(sandbox_binary_.c_str(), X_OK) == 0 &&
-        (st.st_uid == 0) &&
-        (st.st_mode & S_ISUID) &&
-        (st.st_mode & S_IXOTH)) {
-      using_suid_sandbox_ = true;
-      cmd_line.PrependWrapper(ASCIIToWide(sandbox_binary_.c_str()));
-
-      SaveSUIDUnsafeEnvironmentVariables();
-    } else {
-      LOG(FATAL) << "The SUID sandbox helper binary was found, but is not "
-                    "configured correctly. Rather than run without sandboxing "
-                    "I'm aborting now. You need to make sure that "
-                 << sandbox_binary_ << " is mode 4755 and owned by root.";
-    }
-  }
 
   // Start up the sandbox host process and get the file descriptor for the
   // renderers to talk to it.