[Android] Fix Microdump generation when Seccomp-BPF is enabled.

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>
 #include <sys/syscall.h>
 #include <sys/types.h>
 
 #include "build/build_config.h"
 #include "sandbox/linux/bpf_dsl/bpf_dsl.h"
 
+using sandbox::bpf_dsl::AllOf;
 using sandbox::bpf_dsl::Allow;
+using sandbox::bpf_dsl::AnyOf;
+using sandbox::bpf_dsl::Arg;
+using sandbox::bpf_dsl::BoolExpr;
+using sandbox::bpf_dsl::If;
+using sandbox::bpf_dsl::Error;
 using sandbox::bpf_dsl::ResultExpr;
 
 namespace content {
 
+#ifndef SOCK_CLOEXEC
+#define SOCK_CLOEXEC O_CLOEXEC
+#endif
+
+#ifndef SOCK_NONBLOCK
+#define SOCK_NONBLOCK O_NONBLOCK
+#endif
+
+namespace {
+
+// Restricts the arguments to sys_socket() to AF_UNIX. Returns a BoolExpr that
+// evaluates to true if the syscall should be allowed.
+BoolExpr RestrictSocketArguments(const Arg<int>& domain,
+                                 const Arg<int>& type,
+                                 const Arg<int>& protocol) {
+  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() {}
 
 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:
     case __NR_flock:
 #if defined(__x86_64__) || defined(__aarch64__)
     case __NR_newfstatat:
+    case __NR_getdents64:
 #elif defined(__i386__) || defined(__arm__) || defined(__mips__)
     case __NR_fstatat64:
+    case __NR_getdents:
 #endif
     case __NR_getpriority:
     case __NR_ioctl:
     case __NR_mremap:
     // File system access cannot be restricted with seccomp-bpf on Android,
     // since the JVM classloader and other Framework features require file
     // access. It may be possible to restrict the filesystem with SELinux.
     // Currently we rely on the app/service UID isolation to create a
     // filesystem "sandbox".
 #if !defined(ARCH_CPU_ARM64)
     case __NR_open:
 #endif
     case __NR_openat:
     case __NR_pread64:
     case __NR_rt_sigtimedwait:
     case __NR_setpriority:
     case __NR_set_tid_address:
     case __NR_sigaltstack:
 #if defined(__i386__) || defined(__arm__)
     case __NR_ugetrlimit:
 #else
     case __NR_getrlimit:
 #endif
     case __NR_uname:
+
+    // Permit socket operations so that renderers can connect to logd and
+    // debuggerd. The arguments to socket() are further restricted below.
+    // Note that on i386, both of these calls map to __NR_socketcall, which
+    // is demultiplexed below.
+#if defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) || \
+      defined(__mips__)
+    case __NR_socket:
+    case __NR_connect:
+#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;
   }
 
+#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__)
+  if (sysno == __NR_socketcall) {
+    const Arg<int> socketcall(0);
+    const Arg<int> domain(1);
+    const Arg<int> type(2);
+    const Arg<int> protocol(3);
+    return If(socketcall == SYS_CONNECT, Allow())
+           .ElseIf(AllOf(socketcall == SYS_SOCKET,
+                         RestrictSocketArguments(domain, type, protocol)),
+                   Allow())
+           .Else(Error(EPERM));
+  }
+#endif
+
   if (override_and_allow)
     return Allow();
 
   return SandboxBPFBasePolicy::EvaluateSyscall(sysno);
 }
 
 }  // namespace content