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Correct a possible write crash (#494)

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Originate buffer was modified by encryption, which can lead to an EncFS crash, as originate application may not like its buffer to be overwritten
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Ben RUBSON 2018-03-26 08:09:01 +02:00 committed by GitHub
parent b80d30755c
commit 9197385331
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1 changed files with 13 additions and 5 deletions
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18
encfs/BlockFileIO.cpp
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@ -98,15 +98,23 @@ ssize_t BlockFileIO::cacheReadOneBlock(const IORequest &req) const {
} }
ssize_t BlockFileIO::cacheWriteOneBlock(const IORequest &req) { ssize_t BlockFileIO::cacheWriteOneBlock(const IORequest &req) {
// cache results of write (before pass-thru, because it may be modified // Let's point request buffer to our own buffer, as it may be modified by
// in-place) // encryption : originating process may not like to have its buffer modified
memcpy(_cache.data, req.data, req.dataLen); memcpy(_cache.data, req.data, req.dataLen);
_cache.offset = req.offset; IORequest tmp;
_cache.dataLen = req.dataLen; tmp.offset = req.offset;
ssize_t res = writeOneBlock(req); tmp.data = _cache.data;
tmp.dataLen = req.dataLen;
ssize_t res = writeOneBlock(tmp);
if (res < 0) { if (res < 0) {
clearCache(_cache, _blockSize); clearCache(_cache, _blockSize);
} }
else {
// And now we can cache the write buffer from the request
memcpy(_cache.data, req.data, req.dataLen);
_cache.offset = req.offset;
_cache.dataLen = req.dataLen;
}
return res; return res;
} }