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QR-Code-generator
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Updated C++ ByteBuffer and QrSegment code to check and handle integer overflow strictly.

This commit is contained in:
Project Nayuki 2017-04-17 16:32:14 +00:00
parent b7a4605e44
commit 873652a82f
2 changed files with 14 additions and 5 deletions
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13
cpp/BitBuffer.cpp
View File

@ -22,6 +22,7 @@
* Software. * Software.
*/ */
#include <climits>
#include <cstddef> #include <cstddef>
#include "BitBuffer.hpp" #include "BitBuffer.hpp"
@ -44,8 +45,10 @@ std::vector<uint8_t> qrcodegen::BitBuffer::getBytes() const {
void qrcodegen::BitBuffer::appendBits(uint32_t val, int len) { void qrcodegen::BitBuffer::appendBits(uint32_t val, int len) {
if (len < 0 || len > 32 || (len < 32 && (val >> len) != 0)) if (len < 0 || len > 32 || (len < 32 && (val >> len) != 0))
throw "Value out of range"; throw "Value out of range";
size_t newBitLen = bitLength + len; if (INT_MAX - bitLength < len)
while (data.size() * 8 < newBitLen) throw "Buffer too long";
unsigned int newByteLen = ((unsigned int)bitLength + len + 7) / 8;
while (data.size() < newByteLen)
data.push_back(0); data.push_back(0);
for (int i = len - 1; i >= 0; i--, bitLength++) // Append bit by bit for (int i = len - 1; i >= 0; i--, bitLength++) // Append bit by bit
data.at(bitLength >> 3) |= ((val >> i) & 1) << (7 - (bitLength & 7)); data.at(bitLength >> 3) |= ((val >> i) & 1) << (7 - (bitLength & 7));
@ -53,8 +56,10 @@ void qrcodegen::BitBuffer::appendBits(uint32_t val, int len) {
void qrcodegen::BitBuffer::appendData(const QrSegment &seg) { void qrcodegen::BitBuffer::appendData(const QrSegment &seg) {
size_t newBitLen = bitLength + seg.bitLength; if (INT_MAX - bitLength < seg.bitLength)
while (data.size() * 8 < newBitLen) throw "Buffer too long";
unsigned int newByteLen = ((unsigned int)bitLength + seg.bitLength + 7) / 8;
while (data.size() < newByteLen)
data.push_back(0); data.push_back(0);
for (int i = 0; i < seg.bitLength; i++, bitLength++) { // Append bit by bit for (int i = 0; i < seg.bitLength; i++, bitLength++) { // Append bit by bit
int bit = (seg.data.at(i >> 3) >> (7 - (i & 7))) & 1; int bit = (seg.data.at(i >> 3) >> (7 - (i & 7))) & 1;

6
cpp/QrSegment.cpp
View File

@ -22,6 +22,7 @@
* Software. * Software.
*/ */
#include <climits>
#include <cstddef> #include <cstddef>
#include "BitBuffer.hpp" #include "BitBuffer.hpp"
#include "QrSegment.hpp" #include "QrSegment.hpp"
@ -139,7 +140,10 @@ int qrcodegen::QrSegment::getTotalBits(const std::vector<QrSegment> &segs, int v
// Fail if segment length value doesn't fit in the length field's bit-width // Fail if segment length value doesn't fit in the length field's bit-width
if (seg.numChars >= (1 << ccbits)) if (seg.numChars >= (1 << ccbits))
return -1; return -1;
result += 4 + ccbits + seg.bitLength; long temp = (long)result + 4 + ccbits + seg.bitLength;
if (temp > INT_MAX)
return -1;
result = temp;
} }
return result; return result;
} }