Add basic ARM policy to seccomp-bpf sandbox.

content/common/sandbox_seccomp_bpf_linux.cc

Index: content/common/sandbox_seccomp_bpf_linux.cc
diff --git a/content/common/sandbox_seccomp_bpf_linux.cc b/content/common/sandbox_seccomp_bpf_linux.cc
index 226bad780d956b9996052efd54f50aa90125053c..14276b4c9c854f94f4303b25b2410cb21c5dca60 100644
--- a/content/common/sandbox_seccomp_bpf_linux.cc
+++ b/content/common/sandbox_seccomp_bpf_linux.cc
@@ -25,13 +25,18 @@
 #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__)
+#include "sandbox/linux/services/arm_linux_syscalls.h"

[jln (very slow on Chromium), 2012/08/14 20:11:50]

Once you're confident arm is well covered, please rename x86_linux_syscalls.h to
linux_syscalls.h instead and include the arm file from there.

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Will do.

+#endif
 
 namespace {
 
@@ -43,6 +48,14 @@ inline bool IsChromeOS() {
 #endif
 }
 
+inline bool IsARM() {

[jln (very slow on Chromium), 2012/08/14 19:10:35]

You're not using it at the moment.

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Done.

+#if defined(__arm__)
+  return true;
+#else
+  return false;
+#endif
+}
+
 intptr_t CrashSIGSYS_Handler(const struct arch_seccomp_data& args, void* aux) {
   int syscall = args.nr;
   if (syscall >= 1024)
@@ -169,7 +182,11 @@ bool IsAllowedGettime(int sysno) {
   switch (sysno) {
     case __NR_clock_gettime:
     case __NR_gettimeofday:
+    // __NR_time is not available for EABI ARM.
+    // See </arch/arm/include/asm/unistd.h> in the Linux kernel.
+#if !defined(__arm__)

[jln (very slow on Chromium), 2012/08/14 19:10:35]

It's better to whitelist: #if defined(__i386__) || defined(__x86_64__)

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Done.

     case __NR_time:
+#endif
       return true;
     case __NR_adjtimex:         // Privileged.
     case __NR_clock_adjtime:    // Privileged.
@@ -744,7 +761,11 @@ bool IsNuma(int sysno) {
     case __NR_get_mempolicy:
     case __NR_getcpu:
     case __NR_mbind:
+    // __NR_migrate_pages is not available for EABI ARM.
+    // See </arch/arm/include/asm/unistd.h> in the Linux kernel.
+#if !defined(__arm__)

[jln (very slow on Chromium), 2012/08/14 19:10:35]

Same here.

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Done.

     case __NR_migrate_pages:
+#endif
     case __NR_move_pages:
     case __NR_set_mempolicy:
       return true;
@@ -935,6 +956,18 @@ bool IsInotify(int sysno) {
   }
 }
 
+void LogSandboxStarted(const std::string& sandbox_name,

[jln (very slow on Chromium), 2012/08/14 19:10:35]

Rebase issue ? This should not exist in this file.

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Done.

+                       const std::string& process_type) {
+  const std::string activated_sandbox =
+      "Activated " + sandbox_name + " sandbox for process type: " +
+      process_type + ".";
+  if (IsChromeOS()) {
+    LOG(WARNING) << activated_sandbox;
+  } else {
+    VLOG(1) << activated_sandbox;
+  }
+}
+
 bool IsFaNotify(int sysno) {
   switch (sysno) {
     case __NR_fanotify_init:
@@ -1192,7 +1225,11 @@ playground2::Sandbox::ErrorCode BlacklistPtracePolicy(int sysno) {
     return ENOSYS;
   }
   switch (sysno) {
+    // __NR_migrate_pages is not available for EABI ARM.
+    // See </arch/arm/include/asm/unistd.h> in the Linux kernel.
+#if !defined(__arm__)

[jln (very slow on Chromium), 2012/08/14 19:10:35]

Same remark about whitelisting.

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Done.

     case __NR_migrate_pages:
+#endif
     case __NR_move_pages:
     case __NR_process_vm_readv:
     case __NR_process_vm_writev:
@@ -1258,15 +1295,23 @@ playground2::Sandbox::EvaluateSyscall GetProcessSyscallPolicy(
   NOTREACHED();
   // This will be our default if we need one.
   return AllowAllPolicy;
-#else
+#elif defined(__i386__)
   // On IA32, we only have a small blacklist at the moment.
   (void) process_type;
   return BlacklistPtracePolicy;
-#endif  // __x86_64__
+#elif defined(__arm__)
+  // On ARM, we don't block anything yet.

[jln (very slow on Chromium), 2012/08/14 19:10:35]

This seems at odd with what you're doing. Did you mean AllowAllPolicy ?

If not, please merge both in a elif defined i386 || arm.

[Jorge Lucangeli Obes, 2012/08/14 21:58:06]

Done.

+  (void) process_type;
+  return BlacklistPtracePolicy;
+#else
+  // This should not happen, we're compiling only on x86_64 or i386 or ARM.
+  (void) process_type;
+  NOTREACHED();
+#endif
 }
 
 // Initialize the seccomp-bpf sandbox.
-bool StartBpfSandbox_x86(const CommandLine& command_line,
+bool StartBpfSandbox(const CommandLine& command_line,
                          const std::string& process_type) {
   playground2::Sandbox::EvaluateSyscall SyscallPolicy =
       GetProcessSyscallPolicy(command_line, process_type);
@@ -1329,7 +1374,7 @@ bool SandboxSeccompBpf::StartSandbox(const std::string& process_type) {
       // Process-specific policy.
       ShouldEnableSeccompBpf(process_type) &&
       SupportsSandbox()) {
-    return StartBpfSandbox_x86(command_line, process_type);
+    return StartBpfSandbox(command_line, process_type);
   }
 #endif
   return false;