diff options
| author | JUN FANG <jun_fang@foxitsoftware.com> | 2015-05-20 12:25:56 -0700 |
|---|---|---|
| committer | JUN FANG <jun_fang@foxitsoftware.com> | 2015-05-20 12:25:56 -0700 |
| commit | e9ccc9bc449846107f1c539e25677f4877ddf22f (patch) | |
| tree | 95ad9b3d81189bfd211d1c017979db7333428825 /core/src/fxcodec | |
| parent | 3a251306b0fc80eadbd49a806b27c31e285c3223 (diff) | |
| download | pdfium-e9ccc9bc449846107f1c539e25677f4877ddf22f.tar.xz | |
Integer overflow in CJBig2_Image::expand
1. New size should be larger than old size in JBig2_Realloc.
2. Arguments are integers but parameters are size_t in JBIG2_memset.
After integer overflows, it will be presented as a huge
unsigned number on 64 bits system.
BUG=483981
R=brucedawson@chromium.org, tsepez@chromium.org
Review URL: https://codereview.chromium.org/1148643002
Diffstat (limited to 'core/src/fxcodec')
| -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) |