Revert of Revert of Disable yama on 3.2 kernels with 32bit userland and 64bit...

Revert of Revert of Disable yama on 3.2 kernels with 32bit userland and 64bit kernel. (https://codereview.chromium.org/374933002/)

Reason for revert:
[Sheriff] This was fixed already in 281762.

Original issue's description:
> Revert of Disable yama on 3.2 kernels with 32bit userland and 64bit kernel. (https://codereview.chromium.org/371113003/)
> 
> Reason for revert:
> Broke clang builders:
> https://build.chromium.org/p/chromium.linux/builders/Linux%20Clang%20(dbg)/builds/61819/steps/compile/logs/stdio
> 
> Original issue's description:
> > Disable two yama tests on 3.2 kernels with 32bit userland and 64bit kernel.
> > 
> > Disabling yama restrictions is broken there.
> > 
> > BUG=391916
> > R=jorgelo@chromium.org
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281666
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281757
> 
> TBR=jorgelo@chromium.org,keescook@chromium.org,thakis@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=391916
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281763

TBR=jorgelo@chromium.org,keescook@chromium.org,thakis@chromium.org,eseidel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=391916

Review URL: https://codereview.chromium.org/374943002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281764 0039d316-1c4b-4281-b951-d872f2087c98

sandbox/linux/services/yama_unittests.cc

@@ -12,6 +12,8 @@
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/posix/eintr_wrapper.h"
+#include "base/strings/string_util.h"
+#include "base/sys_info.h"
 #include "sandbox/linux/services/scoped_process.h"
 #include "sandbox/linux/services/yama.h"
 #include "sandbox/linux/tests/unit_tests.h"
@@ -21,6 +23,21 @@ namespace sandbox {
 
 namespace {
 
+bool HasLinux32Bug() {
+#if defined(__i386__)
+  // On 3.2 kernels, yama doesn't work for 32-bit binaries on 64-bit kernels.
+  // This is fixed in 3.4.
+  bool is_kernel_64bit =
+      base::SysInfo::OperatingSystemArchitecture() == "x86_64";
+  bool is_linux = base::SysInfo::OperatingSystemName() == "Linux";
+  bool is_3_dot_2 = StartsWithASCII(
+      base::SysInfo::OperatingSystemVersion(), "3.2", /*case_sensitive=*/false);
+  if (is_kernel_64bit && is_linux && is_3_dot_2)
+    return true;
+#endif  // defined(__i386__)
+  return false;
+}
+
 bool CanPtrace(pid_t pid) {
   int ret;
   ret = ptrace(PTRACE_ATTACH, pid, NULL, NULL);