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3cea474ccf
This fixes https://github.com/ClickHouse/ClickHouse/issues/33549 The infinite loop caused because sometimes the pos of ReadBuffer overflows the end. It happens f.e. when `MySQLPacketPayloadReadBuffer::nextImpl` might return empty buffer, because `in.nextIfAtEnd();` could not read more bytes and thus no bytes available (pos == end). It might happen when a network error or the connection to MySQL was closed or killed. This leads to empty `working_buffer` but successful returning from the func. And check `if (in.eof())` from `MySQLBinlogEventReadBuffer::nextImpl()` fails and also causes empty its `working_buffer` and successul return. At the end `payload.ignore(1)` and `payload.read(c)` produces the infinite loop since it is not eof() and ++pos overflows the end of the buffer. Should be tested by `test_mysql_kill*` from test.py
62 lines
1.9 KiB
C++
62 lines
1.9 KiB
C++
#include <IO/MySQLPacketPayloadReadBuffer.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int UNKNOWN_PACKET_FROM_CLIENT;
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}
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const size_t MAX_PACKET_LENGTH = (1 << 24) - 1; // 16 mb
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MySQLPacketPayloadReadBuffer::MySQLPacketPayloadReadBuffer(ReadBuffer & in_, uint8_t & sequence_id_)
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: ReadBuffer(in_.position(), 0), in(in_), sequence_id(sequence_id_) // not in.buffer().begin(), because working buffer may include previous packet
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{
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}
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bool MySQLPacketPayloadReadBuffer::nextImpl()
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{
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if (!has_read_header || (payload_length == MAX_PACKET_LENGTH && offset == payload_length))
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{
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has_read_header = true;
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working_buffer.resize(0);
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offset = 0;
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payload_length = 0;
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in.readStrict(reinterpret_cast<char *>(&payload_length), 3);
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if (payload_length > MAX_PACKET_LENGTH)
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throw Exception(ErrorCodes::UNKNOWN_PACKET_FROM_CLIENT,
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"Received packet with payload larger than max_packet_size: {}", payload_length);
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size_t packet_sequence_id = 0;
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in.readStrict(reinterpret_cast<char &>(packet_sequence_id));
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if (packet_sequence_id != sequence_id)
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throw Exception(ErrorCodes::UNKNOWN_PACKET_FROM_CLIENT,
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"Received packet with wrong sequence-id: {}. Expected: {}.", packet_sequence_id, static_cast<unsigned int>(sequence_id));
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sequence_id++;
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if (payload_length == 0)
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return false;
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}
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else if (offset == payload_length)
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{
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return false;
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}
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in.nextIfAtEnd();
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/// Don't return a buffer when no bytes available
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if (!in.hasPendingData())
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return false;
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working_buffer = ReadBuffer::Buffer(in.position(), in.buffer().end());
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size_t count = std::min(in.available(), payload_length - offset);
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working_buffer.resize(count);
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in.ignore(count);
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offset += count;
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return true;
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}
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}
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