LibIPC: Make sure FDs survive when passed into a MessageBuffer

luteresa · May 2, 2021 · de9b454 · de9b454
1 parent cc6db52
commit de9b454
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Showing 3 changed files with 34 additions and 4 deletions.
diff --git a/Userland/Libraries/LibIPC/Connection.h b/Userland/Libraries/LibIPC/Connection.h
@@ -65,8 +65,8 @@ class Connection : public Core::Object {
  buffer.data.prepend(reinterpret_cast<const u8*>(&message_size), sizeof(message_size));
 
 #ifdef __serenity__
- for (int fd : buffer.fds) {
- auto rc = sendfd(m_socket->fd(), fd);
+ for (auto& fd : buffer.fds) {
+ auto rc = sendfd(m_socket->fd(), fd->value());
  if (rc < 0) {
  perror("sendfd");
  shutdown();

diff --git a/Userland/Libraries/LibIPC/Encoder.cpp b/Userland/Libraries/LibIPC/Encoder.cpp
@@ -148,7 +148,16 @@ Encoder& Encoder::operator<<(const Dictionary& dictionary)
 
 Encoder& Encoder::operator<<(const File& file)
 {
- m_buffer.fds.append(file.fd());
+ int fd = file.fd();
+ if (fd != -1) {
+ auto result = dup(fd);
+ if (result < 0) {
+ perror("dup");
+ VERIFY_NOT_REACHED();
+ }
+ fd = result;
+ }
+ m_buffer.fds.append(adopt_ref(*new AutoCloseFileDescriptor(fd)));
  return *this;
 }
 

diff --git a/Userland/Libraries/LibIPC/Message.h b/Userland/Libraries/LibIPC/Message.h
@@ -7,13 +7,34 @@
 #pragma once
 
 #include <AK/Function.h>
+#include <AK/RefPtr.h>
 #include <AK/Vector.h>
+#include <unistd.h>
 
 namespace IPC {
 
+class AutoCloseFileDescriptor : public RefCounted<AutoCloseFileDescriptor> {
+public:
+ AutoCloseFileDescriptor(int fd)
+ : m_fd(fd)
+ {
+ }
+
+ ~AutoCloseFileDescriptor()
+ {
+ if (m_fd != -1)
+ close(m_fd);
+ }
+
+ int value() const { return m_fd; }
+
+private:
+ int m_fd;
+};
+
 struct MessageBuffer {
  Vector<u8, 1024> data;
- Vector<int> fds;
+ Vector<RefPtr<AutoCloseFileDescriptor>> fds;
 };
 
 class Message {