diff options
| -rw-r--r-- | core/src/fxcodec/jbig2/JBig2_Image.cpp | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/core/src/fxcodec/jbig2/JBig2_Image.cpp b/core/src/fxcodec/jbig2/JBig2_Image.cpp index 03929b84c8..8e27bca80c 100644 --- a/core/src/fxcodec/jbig2/JBig2_Image.cpp +++ b/core/src/fxcodec/jbig2/JBig2_Image.cpp @@ -767,18 +767,25 @@ CJBig2_Image *CJBig2_Image::subImage(FX_INT32 x, FX_INT32 y, FX_INT32 w, FX_INT3 } void CJBig2_Image::expand(FX_INT32 h, FX_BOOL v) { - if (!m_pData) { + if (!m_pData || h <= m_nHeight) { return; } - FX_SAFE_DWORD safeMemSize = pdfium::base::checked_cast<FX_DWORD>(h); - safeMemSize *= pdfium::base::checked_cast<FX_DWORD>(m_nStride); + FX_DWORD dwH = pdfium::base::checked_cast<FX_DWORD>(h); + FX_DWORD dwStride = pdfium::base::checked_cast<FX_DWORD>(m_nStride); + FX_DWORD dwHeight = pdfium::base::checked_cast<FX_DWORD>(m_nHeight); + FX_SAFE_DWORD safeMemSize = dwH; + safeMemSize *= dwStride; if (!safeMemSize.IsValid()) { return; } + //The guaranteed reallocated memory is to be < 4GB (unsigned int). m_pData = (FX_BYTE*)m_pModule->JBig2_Realloc(m_pData, safeMemSize.ValueOrDie()); - if(h > m_nHeight) { - JBIG2_memset(m_pData + m_nHeight * m_nStride, v ? 0xff : 0, (h - m_nHeight)*m_nStride); - } + //The result of dwHeight * dwStride doesn't overflow after the + //checking of safeMemSize. + //The same as the result of (dwH - dwHeight) * dwStride) because + //dwH - dwHeight is always less than dwH(h) which is checked in + //the calculation of dwH * dwStride. + JBIG2_memset(m_pData + dwHeight * dwStride, v ? 0xff : 0, (dwH - dwHeight) * dwStride); m_nHeight = h; } FX_BOOL CJBig2_Image::composeTo_opt2(CJBig2_Image *pDst, FX_INT32 x, FX_INT32 y, JBig2ComposeOp op) |