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Merge pull request #1184 from ZappoMan/bugfixes

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make numberOfThreeBitSectionsInCode() robust against overflowing buffers if length is known
This commit is contained in:
Stephen Birarda 2013-11-05 12:49:53 -08:00
commit 8789f06df3
4 changed files with 33 additions and 5 deletions
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9
libraries/shared/src/OctalCode.cpp
View file

@ -16,10 +16,15 @@
#include "SharedUtil.h"
#include "OctalCode.h"
int numberOfThreeBitSectionsInCode(const unsigned char* octalCode) {
int numberOfThreeBitSectionsInCode(const unsigned char* octalCode, int maxBytes) {
if (maxBytes == OVERFLOWED_OCTCODE_BUFFER) {
return OVERFLOWED_OCTCODE_BUFFER;
}
assert(octalCode);
if (*octalCode == 255) {
return *octalCode + numberOfThreeBitSectionsInCode(octalCode + 1);
int newMaxBytes = (maxBytes == UNKNOWN_OCTCODE_LENGTH) ? UNKNOWN_OCTCODE_LENGTH : maxBytes - 1;
return *octalCode + numberOfThreeBitSectionsInCode(octalCode + 1, newMaxBytes);
} else {
return *octalCode;
}

10
libraries/shared/src/OctalCode.h
View file

@ -24,7 +24,15 @@ void printOctalCode(const unsigned char* octalCode);
int bytesRequiredForCodeLength(unsigned char threeBitCodes);
int branchIndexWithDescendant(const unsigned char* ancestorOctalCode, const unsigned char* descendantOctalCode);
unsigned char* childOctalCode(const unsigned char* parentOctalCode, char childNumber);
int numberOfThreeBitSectionsInCode(const unsigned char* octalCode);
const int OVERFLOWED_OCTCODE_BUFFER = -1;
const int UNKNOWN_OCTCODE_LENGTH = -2;
/// will return -1 if there is an error in the octcode encoding, or it would overflow maxBytes
/// \param const unsigned char* octalCode the octalcode to decode
/// \param int maxBytes number of bytes that octalCode is expected to be, -1 if unknown
int numberOfThreeBitSectionsInCode(const unsigned char* octalCode, int maxBytes = UNKNOWN_OCTCODE_LENGTH);
unsigned char* chopOctalCode(const unsigned char* originalOctalCode, int chopLevels);
unsigned char* rebaseOctalCode(const unsigned char* originalOctalCode, const unsigned char* newParentOctalCode,
bool includeColorSpace = false);

10
libraries/voxel-server-library/src/VoxelServerPacketProcessor.cpp
View file

@ -49,7 +49,15 @@ void VoxelServerPacketProcessor::processPacket(sockaddr& senderAddress, unsigned
int atByte = numBytesPacketHeader + sizeof(itemNumber);
unsigned char* voxelData = (unsigned char*)&packetData[atByte];
while (atByte < packetLength) {
unsigned char octets = numberOfThreeBitSectionsInCode(voxelData);
int maxSize = packetLength - atByte;
unsigned char octets = numberOfThreeBitSectionsInCode(voxelData, maxSize);
if (octets == OVERFLOWED_OCTCODE_BUFFER) {
printf("WARNING! Got voxel edit record that would overflow buffer in numberOfThreeBitSectionsInCode(), ");
printf("bailing processing of packet!\n");
break;
}
const int COLOR_SIZE_IN_BYTES = 3;
int voxelDataSize = bytesRequiredForCodeLength(octets) + COLOR_SIZE_IN_BYTES;
int voxelCodeSize = bytesRequiredForCodeLength(octets);

9
libraries/voxels/src/VoxelTree.cpp
View file

@ -581,7 +581,14 @@ void VoxelTree::processRemoveVoxelBitstream(unsigned char * bitstream, int buffe
int atByte = sizeof(short int) + numBytesForPacketHeader(bitstream);
unsigned char* voxelCode = (unsigned char*)&bitstream[atByte];
while (atByte < bufferSizeBytes) {
int codeLength = numberOfThreeBitSectionsInCode(voxelCode);
int maxSize = bufferSizeBytes - atByte;
unsigned char codeLength = numberOfThreeBitSectionsInCode(voxelCode, maxSize);
if (codeLength == OVERFLOWED_OCTCODE_BUFFER) {
printf("WARNING! Got remove voxel bitstream that would overflow buffer in numberOfThreeBitSectionsInCode(), ");
printf("bailing processing of packet!\n");
break;
}
int voxelDataSize = bytesRequiredForCodeLength(codeLength) + SIZE_OF_COLOR_DATA;
if (atByte + voxelDataSize <= bufferSizeBytes) {