[Android] Allow __NR_rt_tgsigqueueinfo under seccomp.

content/common/sandbox_linux/android/sandbox_bpf_base_policy_android.cc

 // Copyright 2014 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/android/sandbox_bpf_base_policy_android.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/net.h>
 #include <sys/socket.h>
@@ skipping 32 matching lines @@
   const int kSockFlags = SOCK_CLOEXEC | SOCK_NONBLOCK;
   return AllOf(domain == AF_UNIX,
                AnyOf((type & ~kSockFlags) == SOCK_DGRAM,
                      (type & ~kSockFlags) == SOCK_STREAM),
                protocol == 0);
 }
 
 }  // namespace
 
 SandboxBPFBasePolicyAndroid::SandboxBPFBasePolicyAndroid()
-    : SandboxBPFBasePolicy() {}
+    : SandboxBPFBasePolicy(),
+      pid_(getpid()) {}
 
 SandboxBPFBasePolicyAndroid::~SandboxBPFBasePolicyAndroid() {}
 
 ResultExpr SandboxBPFBasePolicyAndroid::EvaluateSyscall(int sysno) const {
   bool override_and_allow = false;
 
   switch (sysno) {
     // TODO(rsesek): restrict clone parameters.
     case __NR_clone:
     case __NR_epoll_pwait:
@@ skipping 51 matching lines @@
     case __NR_socket:
 #endif
 
     // Ptrace is allowed so the Breakpad Microdumper can fork in a renderer
     // and then ptrace the parent.
     case __NR_ptrace:
       override_and_allow = true;
       break;
   }
 
+  // https://crbug.com/644759
+  if (sysno == __NR_rt_tgsigqueueinfo) {
+    const Arg<pid_t> tgid(0);
+    return If(tgid == pid_, Allow())
+           .Else(Error(EPERM));
+  }
+
 #if defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) || \
       defined(__mips__)
   if (sysno == __NR_socket) {
     const Arg<int> domain(0);
     const Arg<int> type(1);
     const Arg<int> protocol(2);
     return If(RestrictSocketArguments(domain, type, protocol), Allow())
            .Else(Error(EPERM));
   }
 #elif defined(__i386__)
@@ skipping 11 matching lines @@
   }
 #endif
 
   if (override_and_allow)
     return Allow();
 
   return SandboxBPFBasePolicy::EvaluateSyscall(sysno);
 }
 
 }  // namespace content