Add basic ARM policy to seccomp-bpf sandbox.

content/common/sandbox_seccomp_bpf_linux.cc

 // 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.
 
 #include <asm/unistd.h>
 #include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/audit.h>
 #include <linux/filter.h>
 #include <signal.h>
 #include <string.h>
 #include <sys/prctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <ucontext.h>
 #include <unistd.h>
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "content/common/sandbox_linux.h"
 #include "content/common/sandbox_seccomp_bpf_linux.h"
 #include "content/public/common/content_switches.h"
 
 // These are the only architectures supported for now.
-#if defined(__i386__) || defined(__x86_64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__arm__)
 #define SECCOMP_BPF_SANDBOX
 #endif
 
 #if defined(SECCOMP_BPF_SANDBOX)
 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
+
+#if defined(__i386__) || defined(__x86_64__)
 #include "sandbox/linux/services/x86_linux_syscalls.h"
+#elif defined(__arm__)
+// This file doesn't yet list all syscalls.
+#include "sandbox/linux/services/arm_linux_syscalls.h"
+#endif
 
 namespace {
 
 inline bool IsChromeOS() {
 #if defined(OS_CHROMEOS)
   return true;
 #else
   return false;
 #endif
 }
@@ skipping 1131 matching lines @@
       // These are under investigation, and hopefully not here for the long
       // term.
       if (IsAllowedSystemVSharedMemory(sysno))
         return playground2::Sandbox::SB_ALLOWED;
 #endif
 
       // Default on the baseline policy.
       return  BaselinePolicy_x86_64(sysno);
   }
 }
 #endif  // defined(__x86_64__) || defined(__i386__)

[jln (very slow on Chromium), 2012/08/14 22:51:46]

This comment has the wrong order, feel free to correct it.

 
 playground2::Sandbox::ErrorCode BlacklistPtracePolicy(int sysno) {
   if (sysno < static_cast<int>(MIN_SYSCALL) ||
       sysno > static_cast<int>(MAX_SYSCALL)) {
     // TODO(jln) we should not have to do that in a trivial policy.
     return ENOSYS;
   }
   switch (sysno) {
+#if defined(__x86_64__) || defined(__i386__)

[jln (very slow on Chromium), 2012/08/14 22:51:46]

The rest of this file does i386 || x86_64, would be nice to do the same.

     case __NR_migrate_pages:
+#endif
     case __NR_move_pages:
     case __NR_process_vm_readv:
     case __NR_process_vm_writev:
     case __NR_ptrace:
       return playground2::Sandbox::ErrorCode(CrashSIGSYS_Handler, NULL);
     default:
       return playground2::Sandbox::SB_ALLOWED;
   }
 }
 
@@ skipping 46 matching lines @@
   }
 
   if (process_type == switches::kRendererProcess ||
       process_type == switches::kWorkerProcess) {
     return BlacklistPtracePolicy;
   }
   NOTREACHED();
   // This will be our default if we need one.
   return AllowAllPolicy;
 #else
-  // On IA32, we only have a small blacklist at the moment.
+  // On other architectures (currently IA32 or ARM),
+  // we only have a small blacklist at the moment.
   (void) process_type;
   return BlacklistPtracePolicy;
 #endif  // __x86_64__
 }
 
 // Initialize the seccomp-bpf sandbox.
-bool StartBpfSandbox_x86(const CommandLine& command_line,
-                         const std::string& process_type) {
+bool StartBpfSandbox(const CommandLine& command_line,
+                     const std::string& process_type) {
   playground2::Sandbox::EvaluateSyscall SyscallPolicy =
       GetProcessSyscallPolicy(command_line, process_type);
 
   // Warms up resources needed by the policy we're about to enable.
   WarmupPolicy(SyscallPolicy);
 
   playground2::Sandbox::setSandboxPolicy(SyscallPolicy, NULL);
   playground2::Sandbox::startSandbox();
 
   return true;
@@ skipping 41 matching lines @@
 }
 
 bool SandboxSeccompBpf::StartSandbox(const std::string& process_type) {
 #if defined(SECCOMP_BPF_SANDBOX)
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (IsSeccompBpfDesired() &&  // Global switches policy.
       // Process-specific policy.
       ShouldEnableSeccompBpf(process_type) &&
       SupportsSandbox()) {
-    return StartBpfSandbox_x86(command_line, process_type);
+    return StartBpfSandbox(command_line, process_type);
   }
 #endif
   return false;
 }
 
 }  // namespace content