Add safe FX_Alloc2D() macro

This avoids unchecked multiplications when computing a size argument
to malloc(). Such an overflow is very scary, and can result in
exploitable bugs.

Along the way, kill off some return checks, since we know this can't
return NULL.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1143663004

2 files changed, 9 insertions, 9 deletions

diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index b6bf7950ff..8b9ff8ea96 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -643,7 +643,7 @@ FX_BOOL CPDF_ICCBasedCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray)
         }
     }
     CPDF_Array* pRanges = pDict->GetArray(FX_BSTRC("Range"));
-    m_pRanges = FX_Alloc(FX_FLOAT, m_nComponents * 2);
+    m_pRanges = FX_Alloc2D(FX_FLOAT, m_nComponents, 2);
     for (int i = 0; i < m_nComponents * 2; i ++) {
         if (pRanges) {
             m_pRanges[i] = pRanges->GetNumber(i);
@@ -715,8 +715,8 @@ void CPDF_ICCBasedCS::TranslateImageLine(FX_LPBYTE pDestBuf, FX_LPCBYTE pSrcBuf,
             CPDF_ModuleMgr::Get()->GetIccModule()->TranslateScanline(m_pProfile->m_pTransform, pDestBuf, pSrcBuf, pixels);
         } else {
             if (m_pCache == NULL) {
-                ((CPDF_ICCBasedCS*)this)->m_pCache = FX_Alloc(FX_BYTE, nMaxColors * 3);
-                FX_LPBYTE temp_src = FX_Alloc(FX_BYTE, nMaxColors * m_nComponents);
+                ((CPDF_ICCBasedCS*)this)->m_pCache = FX_Alloc2D(FX_BYTE, nMaxColors, 3);
+                FX_LPBYTE temp_src = FX_Alloc2D(FX_BYTE, nMaxColors, m_nComponents);
                 FX_LPBYTE pSrc = temp_src;
                 for (int i = 0; i < nMaxColors; i ++) {
                     FX_DWORD color = i;
@@ -804,7 +804,7 @@ FX_BOOL CPDF_IndexedCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray)
     }
     m_pCountedBaseCS = pDocPageData->FindColorSpacePtr(m_pBaseCS->GetArray());
     m_nBaseComponents = m_pBaseCS->CountComponents();
-    m_pCompMinMax = FX_Alloc(FX_FLOAT, m_nBaseComponents * 2);
+    m_pCompMinMax = FX_Alloc2D(FX_FLOAT, m_nBaseComponents, 2);
     FX_FLOAT defvalue;
     for (int i = 0; i < m_nBaseComponents; i ++) {
         m_pBaseCS->GetDefaultValue(i, defvalue, m_pCompMinMax[i * 2], m_pCompMinMax[i * 2 + 1]);
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
index bd1cdb6434..8ec490a9e8 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
@@ -670,8 +670,8 @@ FX_BOOL CPDF_ExpIntFunc::v_Init(CPDF_Object* pObj)
         }
     }
     CPDF_Array* pArray1 = pDict->GetArray(FX_BSTRC("C1"));
-    m_pBeginValues = FX_Alloc(FX_FLOAT, m_nOutputs * 2);
-    m_pEndValues = FX_Alloc(FX_FLOAT, m_nOutputs * 2);
+    m_pBeginValues = FX_Alloc2D(FX_FLOAT, m_nOutputs, 2);
+    m_pEndValues = FX_Alloc2D(FX_FLOAT, m_nOutputs, 2);
     for (int i = 0; i < m_nOutputs; i ++) {
         m_pBeginValues[i] = pArray0 ? pArray0->GetFloat(i) : 0.0f;
         m_pEndValues[i] = pArray1 ? pArray1->GetFloat(i) : 1.0f;
@@ -768,7 +768,7 @@ FX_BOOL CPDF_StitchFunc::v_Init(CPDF_Object* pObj)
         m_pBounds[i + 1] = pArray->GetFloat(i);
     }
     m_pBounds[m_nSubs] = m_pDomains[1];
-    m_pEncode = FX_Alloc(FX_FLOAT, m_nSubs * 2);
+    m_pEncode = FX_Alloc2D(FX_FLOAT, m_nSubs, 2);
     pArray = pDict->GetArray(FX_BSTRC("Encode"));
     if (pArray == NULL) {
         return FALSE;
@@ -857,7 +857,7 @@ FX_BOOL CPDF_Function::Init(CPDF_Object* pObj)
     if (m_nInputs == 0) {
         return FALSE;
     }
-    m_pDomains = FX_Alloc(FX_FLOAT, m_nInputs * 2);
+    m_pDomains = FX_Alloc2D(FX_FLOAT, m_nInputs, 2);
     for (int i = 0; i < m_nInputs * 2; i ++) {
         m_pDomains[i] = pDomains->GetFloat(i);
     }
@@ -865,7 +865,7 @@ FX_BOOL CPDF_Function::Init(CPDF_Object* pObj)
     m_nOutputs = 0;
     if (pRanges) {
         m_nOutputs = pRanges->GetCount() / 2;
-        m_pRanges = FX_Alloc(FX_FLOAT, m_nOutputs * 2);
+        m_pRanges = FX_Alloc2D(FX_FLOAT, m_nOutputs, 2);
         for (int i = 0; i < m_nOutputs * 2; i ++) {
             m_pRanges[i] = pRanges->GetFloat(i);
         }