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fix potential DoS vulnerability (through memory exhaustion) by restricting maximum line length

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This commit is contained in:
Guenter Obiltschnig 2017-01-24 13:13:13 +01:00
parent 3577724efd
commit 4392f13b9c
2 changed files with 16 additions and 10 deletions
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8
Net/include/Poco/Net/DialogSocket.h
View File

@ -22,6 +22,7 @@
#include "Poco/Net/Net.h"
#include "Poco/Net/StreamSocket.h"
#include <cstdlib>
namespace Poco {
@ -80,7 +81,7 @@ public:
DialogSocket& operator = (const DialogSocket& socket);
/// Assignment operator.
void sendByte(unsigned char ch);
/// Sends a single byte over the socket connection.
@ -189,13 +190,14 @@ public:
protected:
void allocBuffer();
void refill();
bool receiveLine(std::string& line);
int receiveStatusLine(std::string& line);
bool receiveLine(std::string& line, std::size_t lineLengthLimit = 0);
int receiveStatusLine(std::string& line, std::size_t lineLengthLimit = 0);
private:
enum
{
RECEIVE_BUFFER_SIZE = 1024,
MAX_LINE_LENGTH = 4096,
EOF_CHAR = -1
};

18
Net/src/DialogSocket.cpp
View File

@ -15,6 +15,7 @@
#include "Poco/Net/DialogSocket.h"
#include "Poco/Exception.h"
#include "Poco/Ascii.h"
#include <cstring>
@ -149,20 +150,20 @@ void DialogSocket::sendMessage(const std::string& message, const std::string& ar
bool DialogSocket::receiveMessage(std::string& message)
{
message.clear();
return receiveLine(message);
return receiveLine(message, MAX_LINE_LENGTH);
}
int DialogSocket::receiveStatusMessage(std::string& message)
{
message.clear();
int status = receiveStatusLine(message);
int status = receiveStatusLine(message, MAX_LINE_LENGTH);
if (status < 0)
{
while (status <= 0)
{
message += '\n';
status = receiveStatusLine(message);
status = receiveStatusLine(message, MAX_LINE_LENGTH);
}
}
return status;
@ -236,14 +237,17 @@ void DialogSocket::allocBuffer()
}
bool DialogSocket::receiveLine(std::string& line)
bool DialogSocket::receiveLine(std::string& line, std::size_t lineLengthLimit)
{
// An old wisdom goes: be strict in what you emit
// and generous in what you accept.
int ch = get();
while (ch != EOF_CHAR && ch != '\r' && ch != '\n')
{
line += (char) ch;
if (lineLengthLimit == 0 || line.size() < lineLengthLimit)
line += (char) ch;
else
throw Poco::IOException("Line too long");
ch = get();
}
if (ch == '\r' && peek() == '\n')
@ -254,7 +258,7 @@ bool DialogSocket::receiveLine(std::string& line)
}
int DialogSocket::receiveStatusLine(std::string& line)
int DialogSocket::receiveStatusLine(std::string& line, std::size_t lineLengthLimit)
{
int status = 0;
int ch = get();
@ -274,7 +278,7 @@ int DialogSocket::receiveStatusLine(std::string& line)
status = -status;
}
else status = 0;
if (ch != EOF_CHAR) receiveLine(line);
if (ch != EOF_CHAR) receiveLine(line, lineLengthLimit);
return status;
}