From ca94a833374b3fec720cc8ee911b9824c3021828 Mon Sep 17 00:00:00 2001
From: Brian Gianforcaro <bgianf@serenityos.org>
Date: Sun, 1 Aug 2021 02:42:03 -0700
Subject: Kernel: Handle OOM from DoubleBuffer usage in IPv4Socket

The IPv4Socket requires a DoubleBuffer for storage of any data it
received on the socket. However it was previously using the default
constructor which can not observe allocation failure. Address this by
plumbing the receive buffer through the various derived classes.
---
 Kernel/Net/IPv4Socket.cpp | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

(limited to 'Kernel/Net/IPv4Socket.cpp')

diff --git a/Kernel/Net/IPv4Socket.cpp b/Kernel/Net/IPv4Socket.cpp
index a539b4c503..9f27421697 100644
--- a/Kernel/Net/IPv4Socket.cpp
+++ b/Kernel/Net/IPv4Socket.cpp
@@ -35,22 +35,31 @@ Lockable<HashTable<IPv4Socket*>>& IPv4Socket::all_sockets()
     return *s_table;
 }
 
+OwnPtr<DoubleBuffer> IPv4Socket::create_receive_buffer()
+{
+    return DoubleBuffer::try_create(256 * KiB);
+}
+
 KResultOr<NonnullRefPtr<Socket>> IPv4Socket::create(int type, int protocol)
 {
+    auto receive_buffer = IPv4Socket::create_receive_buffer();
+    if (!receive_buffer)
+        return ENOMEM;
+
     if (type == SOCK_STREAM) {
-        auto tcp_socket = TCPSocket::create(protocol);
+        auto tcp_socket = TCPSocket::create(protocol, receive_buffer.release_nonnull());
         if (tcp_socket.is_error())
             return tcp_socket.error();
         return tcp_socket.release_value();
     }
     if (type == SOCK_DGRAM) {
-        auto udp_socket = UDPSocket::create(protocol);
+        auto udp_socket = UDPSocket::create(protocol, receive_buffer.release_nonnull());
         if (udp_socket.is_error())
             return udp_socket.error();
         return udp_socket.release_value();
     }
     if (type == SOCK_RAW) {
-        auto raw_socket = adopt_ref_if_nonnull(new (nothrow) IPv4Socket(type, protocol));
+        auto raw_socket = adopt_ref_if_nonnull(new (nothrow) IPv4Socket(type, protocol, receive_buffer.release_nonnull()));
         if (raw_socket)
             return raw_socket.release_nonnull();
         return ENOMEM;
@@ -58,8 +67,9 @@ KResultOr<NonnullRefPtr<Socket>> IPv4Socket::create(int type, int protocol)
     return EINVAL;
 }
 
-IPv4Socket::IPv4Socket(int type, int protocol)
+IPv4Socket::IPv4Socket(int type, int protocol, NonnullOwnPtr<DoubleBuffer> receive_buffer)
     : Socket(AF_INET, type, protocol)
+    , m_receive_buffer(move(receive_buffer))
 {
     dbgln_if(IPV4_SOCKET_DEBUG, "IPv4Socket({}) created with type={}, protocol={}", this, type, protocol);
     m_buffer_mode = type == SOCK_STREAM ? BufferMode::Bytes : BufferMode::Packets;
@@ -248,7 +258,7 @@ KResultOr<size_t> IPv4Socket::sendto(FileDescription&, const UserOrKernelBuffer&
 KResultOr<size_t> IPv4Socket::receive_byte_buffered(FileDescription& description, UserOrKernelBuffer& buffer, size_t buffer_length, int flags, Userspace<sockaddr*>, Userspace<socklen_t*>)
 {
     MutexLocker locker(lock());
-    if (m_receive_buffer.is_empty()) {
+    if (m_receive_buffer->is_empty()) {
         if (protocol_is_disconnected())
             return 0;
         if (!description.is_blocking())
@@ -270,14 +280,14 @@ KResultOr<size_t> IPv4Socket::receive_byte_buffered(FileDescription& description
 
     KResultOr<size_t> nreceived_or_error { 0 };
     if (flags & MSG_PEEK)
-        nreceived_or_error = m_receive_buffer.peek(buffer, buffer_length);
+        nreceived_or_error = m_receive_buffer->peek(buffer, buffer_length);
     else
-        nreceived_or_error = m_receive_buffer.read(buffer, buffer_length);
+        nreceived_or_error = m_receive_buffer->read(buffer, buffer_length);
 
     if (!nreceived_or_error.is_error() && nreceived_or_error.value() > 0 && !(flags & MSG_PEEK))
         Thread::current()->did_ipv4_socket_read(nreceived_or_error.value());
 
-    set_can_read(!m_receive_buffer.is_empty());
+    set_can_read(!m_receive_buffer->is_empty());
     return nreceived_or_error;
 }
 
@@ -406,7 +416,7 @@ bool IPv4Socket::did_receive(const IPv4Address& source_address, u16 source_port,
     auto packet_size = packet.size();
 
     if (buffer_mode() == BufferMode::Bytes) {
-        size_t space_in_receive_buffer = m_receive_buffer.space_for_writing();
+        size_t space_in_receive_buffer = m_receive_buffer->space_for_writing();
         if (packet_size > space_in_receive_buffer) {
             dbgln("IPv4Socket({}): did_receive refusing packet since buffer is full.", this);
             VERIFY(m_can_read);
@@ -416,10 +426,10 @@ bool IPv4Socket::did_receive(const IPv4Address& source_address, u16 source_port,
         auto nreceived_or_error = protocol_receive(ReadonlyBytes { packet.data(), packet.size() }, scratch_buffer, m_scratch_buffer.value().size(), 0);
         if (nreceived_or_error.is_error())
             return false;
-        auto nwritten_or_error = m_receive_buffer.write(scratch_buffer, nreceived_or_error.value());
+        auto nwritten_or_error = m_receive_buffer->write(scratch_buffer, nreceived_or_error.value());
         if (nwritten_or_error.is_error())
             return false;
-        set_can_read(!m_receive_buffer.is_empty());
+        set_can_read(!m_receive_buffer->is_empty());
     } else {
         if (m_receive_queue.size() > 2000) {
             dbgln("IPv4Socket({}): did_receive refusing packet since queue is full.", this);
-- 
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