diff options
author | Rubidium <rubidium@openttd.org> | 2021-04-18 09:01:27 +0200 |
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committer | rubidium42 <rubidium42@users.noreply.github.com> | 2021-04-24 20:42:01 +0200 |
commit | c545cc9d7039a89e23de160b1c93adc959eabda5 (patch) | |
tree | 8522a8e09c0b9fa7e3eba8b4becaef15080f5605 /src/network/core/packet.cpp | |
parent | 470d8b66372ceb5a38ce9823d451bddd2f3eca35 (diff) | |
download | openttd-c545cc9d7039a89e23de160b1c93adc959eabda5.tar.xz |
Codechange: move more logic about packet size validity and reading into Packet
Diffstat (limited to 'src/network/core/packet.cpp')
-rw-r--r-- | src/network/core/packet.cpp | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/src/network/core/packet.cpp b/src/network/core/packet.cpp index 94ffcc558..4eb0e929e 100644 --- a/src/network/core/packet.cpp +++ b/src/network/core/packet.cpp @@ -181,13 +181,32 @@ bool Packet::CanReadFromPacket(uint bytes_to_read) } /** + * Check whether the packet, given the position of the "write" pointer, has read + * enough of the packet to contain its size. + * @return True iff there is enough data in the packet to contain the packet's size. + */ +bool Packet::HasPacketSizeData() const +{ + return this->pos >= sizeof(PacketSize); +} + +/** * Reads the packet size from the raw packet and stores it in the packet->size + * @return True iff the packet size seems plausible. */ -void Packet::ReadRawPacketSize() +bool Packet::ParsePacketSize() { assert(this->cs != nullptr && this->next == nullptr); this->size = (PacketSize)this->buffer[0]; this->size += (PacketSize)this->buffer[1] << 8; + + /* If the size of the packet is less than the bytes required for the size and type of + * the packet, or more than the allowed limit, then something is wrong with the packet. + * In those cases the packet can generally be regarded as containing garbage data. */ + if (this->size < sizeof(PacketSize) + sizeof(PacketType) || this->size > SEND_MTU) return false; + + this->pos = sizeof(PacketSize); + return true; } /** @@ -195,8 +214,6 @@ void Packet::ReadRawPacketSize() */ void Packet::PrepareToRead() { - this->ReadRawPacketSize(); - /* Put the position on the right place */ this->pos = sizeof(PacketSize); } |