seedlingattempt/godot
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

PacketPeer use heap buffer for var encoding.

Browse Source 
Used to allocate in stack (via alloca) which causes crashes when trying
to encode big variables.
The buffer grows as needed up to `encode_buffer_max_size` (which is
8MiB by default) and always in power of 2.
This commit is contained in:
Fabio Alessandrelli
2020-01-18 19:52:59 +01:00
parent d4a222cd9d
commit 534bf89976
2 changed files with 34 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
core/io/packet_peer.cpp
View File

@ -37,7 +37,8 @@
PacketPeer::PacketPeer() : PacketPeer::PacketPeer() :
last_get_error(OK), last_get_error(OK),
allow_object_decoding(false) { allow_object_decoding(false),
encode_buffer_max_size(8 * 1024 * 1024) {
} }
void PacketPeer::set_allow_object_decoding(bool p_enable) { void PacketPeer::set_allow_object_decoding(bool p_enable) {
@ -50,6 +51,19 @@ bool PacketPeer::is_object_decoding_allowed() const {
return allow_object_decoding; return allow_object_decoding;
} }
void PacketPeer::set_encode_buffer_max_size(int p_max_size) {
ERR_FAIL_COND_MSG(p_max_size < 1024, "Max encode buffer must be at least 1024 bytes");
ERR_FAIL_COND_MSG(p_max_size > 256 * 1024 * 1024, "Max encode buffer cannot exceed 256 MiB");
encode_buffer_max_size = next_power_of_2(p_max_size);
encode_buffer.resize(0);
}
int PacketPeer::get_encode_buffer_max_size() const {
return encode_buffer_max_size;
}
Error PacketPeer::get_packet_buffer(PoolVector<uint8_t> &r_buffer) { Error PacketPeer::get_packet_buffer(PoolVector<uint8_t> &r_buffer) {
const uint8_t *buffer; const uint8_t *buffer;
@ -100,12 +114,18 @@ Error PacketPeer::put_var(const Variant &p_packet, bool p_full_objects) {
if (len == 0) if (len == 0)
return OK; return OK;
uint8_t *buf = (uint8_t *)alloca(len); ERR_FAIL_COND_V_MSG(len > encode_buffer_max_size, ERR_OUT_OF_MEMORY, "Failed to encode variant, encode size is bigger then encode_buffer_max_size. Consider raising it via 'set_encode_buffer_max_size'.");
ERR_FAIL_COND_V_MSG(!buf, ERR_OUT_OF_MEMORY, "Out of memory.");
err = encode_variant(p_packet, buf, len, p_full_objects || allow_object_decoding); if (unlikely(encode_buffer.size() < len)) {
encode_buffer.resize(0); // Avoid realloc
encode_buffer.resize(next_power_of_2(len));
}
PoolVector<uint8_t>::Write w = encode_buffer.write();
err = encode_variant(p_packet, w.ptr(), len, p_full_objects || allow_object_decoding);
ERR_FAIL_COND_V_MSG(err != OK, err, "Error when trying to encode Variant."); ERR_FAIL_COND_V_MSG(err != OK, err, "Error when trying to encode Variant.");
return put_packet(buf, len); return put_packet(w.ptr(), len);
} }
Variant PacketPeer::_bnd_get_var(bool p_allow_objects) { Variant PacketPeer::_bnd_get_var(bool p_allow_objects) {
@ -142,7 +162,10 @@ void PacketPeer::_bind_methods() {
ClassDB::bind_method(D_METHOD("set_allow_object_decoding", "enable"), &PacketPeer::set_allow_object_decoding); ClassDB::bind_method(D_METHOD("set_allow_object_decoding", "enable"), &PacketPeer::set_allow_object_decoding);
ClassDB::bind_method(D_METHOD("is_object_decoding_allowed"), &PacketPeer::is_object_decoding_allowed); ClassDB::bind_method(D_METHOD("is_object_decoding_allowed"), &PacketPeer::is_object_decoding_allowed);
ClassDB::bind_method(D_METHOD("get_encode_buffer_max_size"), &PacketPeer::get_encode_buffer_max_size);
ClassDB::bind_method(D_METHOD("set_encode_buffer_max_size", "max_size"), &PacketPeer::set_encode_buffer_max_size);
ADD_PROPERTY(PropertyInfo(Variant::INT, "encode_buffer_max_size"), "set_encode_buffer_max_size", "get_encode_buffer_max_size");
ADD_PROPERTY(PropertyInfo(Variant::BOOL, "allow_object_decoding"), "set_allow_object_decoding", "is_object_decoding_allowed"); ADD_PROPERTY(PropertyInfo(Variant::BOOL, "allow_object_decoding"), "set_allow_object_decoding", "is_object_decoding_allowed");
}; };

6
core/io/packet_peer.h
View File

@ -51,6 +51,9 @@ class PacketPeer : public Reference {
bool allow_object_decoding; bool allow_object_decoding;
int encode_buffer_max_size;
PoolVector<uint8_t> encode_buffer;
public: public:
virtual int get_available_packet_count() const = 0; virtual int get_available_packet_count() const = 0;
virtual Error get_packet(const uint8_t **r_buffer, int &r_buffer_size) = 0; ///< buffer is GONE after next get_packet virtual Error get_packet(const uint8_t **r_buffer, int &r_buffer_size) = 0; ///< buffer is GONE after next get_packet
@ -69,6 +72,9 @@ public:
void set_allow_object_decoding(bool p_enable); void set_allow_object_decoding(bool p_enable);
bool is_object_decoding_allowed() const; bool is_object_decoding_allowed() const;
void set_encode_buffer_max_size(int p_max_size);
int get_encode_buffer_max_size() const;
PacketPeer(); PacketPeer();
~PacketPeer() {} ~PacketPeer() {}
}; };