Adding checks in sandbox code to get some data on AppContainer based CreateProcess failures.

sandbox/win/src/target_process.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 "sandbox/win/src/target_process.h"
 
 #include "base/basictypes.h"
+#include "base/debug/alias.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/win/pe_image.h"
 #include "base/win/startup_information.h"
 #include "base/win/windows_version.h"
 #include "sandbox/win/src/crosscall_server.h"
 #include "sandbox/win/src/crosscall_client.h"
 #include "sandbox/win/src/policy_low_level.h"
 #include "sandbox/win/src/sandbox_types.h"
 #include "sandbox/win/src/sharedmem_ipc_server.h"
 #include "sandbox/win/src/win_utils.h"
@@ skipping 132 matching lines @@
     if (!::CreateProcess(exe_path,
                          cmd_line.get(),
                          NULL,   // No security attribute.
                          NULL,   // No thread attribute.
                          inherit_handles,
                          flags,
                          NULL,   // Use the environment of the caller.
                          NULL,   // Use current directory of the caller.
                          startup_info.startup_info(),
                          &temp_process_info)) {
+      // TODO(shrikant): Remove following code once we gather some crashes for
+      // debugging appcontainer related failures (crbug.com/467920).
+      base::debug::Alias(exe_path);
+      CHECK(FALSE);

[Will Harris, 2015/04/15 23:56:29]

Have you considered just returning a new SBOX error code here? Then the error
should appear in Process.Sandbox.Launch.Error UMA histogram

also - is this the same issue as 385714 and 453541, it certainly looks like it
from the bug...

[Shrikant Kelkar, 2015/04/16 00:06:36]

Yes, that's what I was communicating with reporter earlier. I think reporter
definitely is stuck with issues 385714, but besides that I am receiving 122
ERROR_INSUFFICIENT_BUFFER which I want to find reason for.

This function returns GetLastError codes, sorry but didn't get what you mean by
return SBOX error code.

[Will Harris, 2015/04/16 00:13:36]

ah okay I meant instead of returning GetLastError you could create six new
SBOX_* error codes in sandbox_types.h then return a different one from each
potential failure point, in order to know where it's failing, rather than doing
a CHECK() which will terminate the browser process.

However, this would mean losing the GetLastError() since you can only return one
thing - so perhaps just if(::GetLastError() == ERROR_INSUFFICIENT_BUFFER) checks
around the new error codes?

You could also consider using base::debug::DumpWithoutCrashing() if you want the
diagnosis code not to terminate the browser process.

[Shrikant Kelkar, 2015/04/16 18:25:34]

Basically, I don't want to make these changes permanent in src/sandbox/.. It
just get more diagnostic information and then revert, as I am running out of
option finding the root cause.

DumpWithoutCrashing was the option I tried before, but that was in
content/../sandbox_win.cc, the mystery remains which exact function from
TargetProcess::Create fails with ERROR_INSUFFICIENT_BUFFER. IIRC cpu/rvargas had
a different take on adding DumpWithoutCrashing into src/sandbox/.. (Bringing in
dependency). I guess.. if I am going to revert immediately cpu@ may allow this
:).

       return ::GetLastError();
     }
   } else {
     if (!::CreateProcessAsUserW(scoped_lockdown_token.Get(),
                                 exe_path,
                                 cmd_line.get(),
                                 NULL,   // No security attribute.
                                 NULL,   // No thread attribute.
                                 inherit_handles,
                                 flags,
                                 NULL,   // Use the environment of the caller.
                                 NULL,   // Use current directory of the caller.
                                 startup_info.startup_info(),
                                 &temp_process_info)) {
       return ::GetLastError();
     }
   }
   base::win::ScopedProcessInformation process_info(temp_process_info);
 
   DWORD win_result = ERROR_SUCCESS;
 
   if (job_) {
     // Assign the suspended target to the windows job object.
     if (!::AssignProcessToJobObject(job_, process_info.process_handle())) {
       win_result = ::GetLastError();
+      if (set_lockdown_token_after_create) {
+        // TODO(shrikant): Remove this code once we gather some crashes for
+        // debugging appcontainer related failures (crbug.com/467920).
+        base::debug::Alias(&win_result);
+        CHECK(FALSE);
+      }
       ::TerminateProcess(process_info.process_handle(), 0);
       return win_result;
     }
   }
 
   if (initial_token_.IsValid()) {
     // Change the token of the main thread of the new process for the
     // impersonation token with more rights. This allows the target to start;
     // otherwise it will crash too early for us to help.
     HANDLE temp_thread = process_info.thread_handle();
     if (!::SetThreadToken(&temp_thread, initial_token_.Get())) {
       win_result = ::GetLastError();
+      if (set_lockdown_token_after_create) {
+        // TODO(shrikant): Remove this code once we gather some crashes for
+        // debugging appcontainer related failures (crbug.com/467920).
+        base::debug::Alias(&win_result);
+        CHECK(FALSE);
+      }
       // It might be a security breach if we let the target run outside the job
       // so kill it before it causes damage.
       ::TerminateProcess(process_info.process_handle(), 0);
       return win_result;
     }
     initial_token_.Close();
   }
 
   if (set_lockdown_token_after_create) {
     PROCESS_ACCESS_TOKEN process_access_token;
     process_access_token.thread = process_info.thread_handle();
     process_access_token.token = scoped_lockdown_token.Get();
 
     NtSetInformationProcess SetInformationProcess = NULL;
     ResolveNTFunctionPtr("NtSetInformationProcess", &SetInformationProcess);
 
     NTSTATUS status = SetInformationProcess(
         process_info.process_handle(),
         static_cast<PROCESS_INFORMATION_CLASS>(NtProcessInformationAccessToken),
         &process_access_token,
         sizeof(process_access_token));
     if (!NT_SUCCESS(status)) {
       win_result = ::GetLastError();
+      // TODO(shrikant): Remove this code once we gather some crashes for
+      // debugging appcontainer related failures (crbug.com/467920).
+      base::debug::Alias(&win_result);
+      CHECK(FALSE);
       ::TerminateProcess(process_info.process_handle(), 0);  // exit code
       return win_result;
     }
   }
 
   CONTEXT context;
   context.ContextFlags = CONTEXT_ALL;
   if (!::GetThreadContext(process_info.thread_handle(), &context)) {
     win_result = ::GetLastError();
+    if (set_lockdown_token_after_create) {
+      // TODO(shrikant): Remove this code once we gather some crashes for
+      // debugging appcontainer related failures (crbug.com/467920).
+      base::debug::Alias(&win_result);
+      CHECK(FALSE);
+    }
     ::TerminateProcess(process_info.process_handle(), 0);
     return win_result;
   }
 
 #if defined(_WIN64)
   void* entry_point = reinterpret_cast<void*>(context.Rcx);
 #else
 #pragma warning(push)
 #pragma warning(disable: 4312)
   // This cast generates a warning because it is 32 bit specific.
   void* entry_point = reinterpret_cast<void*>(context.Eax);
 #pragma warning(pop)
 #endif  // _WIN64
 
   if (!target_info->DuplicateFrom(process_info)) {
     win_result = ::GetLastError();  // This may or may not be correct.
+    if (set_lockdown_token_after_create) {
+      // TODO(shrikant): Remove this code once we gather some crashes for
+      // debugging appcontainer related failures (crbug.com/467920).
+      base::debug::Alias(&win_result);
+      CHECK(FALSE);
+    }
     ::TerminateProcess(process_info.process_handle(), 0);
     return win_result;
   }
 
   base_address_ = GetBaseAddress(exe_path, entry_point);
   sandbox_process_info_.Set(process_info.Take());
   return win_result;
 }
 
 ResultCode TargetProcess::TransferVariable(const char* name, void* address,
@@ skipping 121 matching lines @@
 TargetProcess* MakeTestTargetProcess(HANDLE process, HMODULE base_address) {
   TargetProcess* target = new TargetProcess(NULL, NULL, NULL, NULL);
   PROCESS_INFORMATION process_info = {};
   process_info.hProcess = process;
   target->sandbox_process_info_.Set(process_info);
   target->base_address_ = base_address;
   return target;
 }
 
 }  // namespace sandbox