Linux sandbox: restrict prctl in the baseline.

content/common/sandbox_linux/bpf_gpu_policy_linux.cc

 // Copyright (c) 2013 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 "content/common/sandbox_linux/bpf_gpu_policy_linux.h"
 
 #include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/socket.h>
@@ skipping 161 matching lines @@
   switch (sysno) {
     case __NR_ioctl:
 #if defined(__i386__) || defined(__x86_64__)
     // The Nvidia driver uses flags not in the baseline policy
     // (MAP_LOCKED | MAP_EXECUTABLE | MAP_32BIT)
     case __NR_mmap:
 #endif
     // We also hit this on the linux_chromeos bot but don't yet know what
     // weird flags were involved.
     case __NR_mprotect:
+    // TODO(jln): restrict prctl.
+    case __NR_prctl:
     case __NR_sched_getaffinity:
     case __NR_sched_setaffinity:
     case __NR_setpriority:
       return ErrorCode(ErrorCode::ERR_ALLOWED);
     case __NR_access:
     case __NR_open:
     case __NR_openat:
       DCHECK(broker_process_);
       return sandbox->Trap(GpuSIGSYS_Handler, broker_process_);
     default:
@@ skipping 68 matching lines @@
   broker_process_ = new BrokerProcess(GetFSDeniedErrno(),
                                       read_whitelist,
                                       write_whitelist);
   // The initialization callback will perform generic initialization and then
   // call broker_sandboxer_callback.
   CHECK(broker_process_->Init(base::Bind(&UpdateProcessTypeAndEnableSandbox,
                                          broker_sandboxer_allocator)));
 }
 
 }  // namespace content