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-rw-r--r--core/include/fxcrt/fx_basic.h4
-rw-r--r--core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp36
2 files changed, 23 insertions, 17 deletions
diff --git a/core/include/fxcrt/fx_basic.h b/core/include/fxcrt/fx_basic.h
index c21a4f54c5..d5673271e6 100644
--- a/core/include/fxcrt/fx_basic.h
+++ b/core/include/fxcrt/fx_basic.h
@@ -916,9 +916,9 @@ class CFX_BitStream {
void Rewind() { m_BitPos = 0; }
- FX_DWORD GetPos() { return m_BitPos; }
+ FX_DWORD GetPos() const { return m_BitPos; }
- FX_DWORD BitsRemaining() {
+ FX_DWORD BitsRemaining() const {
return m_BitSize >= m_BitPos ? m_BitSize - m_BitPos : 0;
}
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index db9e177976..c2a856cb50 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -75,6 +75,12 @@ int32_t GetStreamFirst(CPDF_StreamAcc* pObjStream) {
return pObjStream->GetDict()->GetInteger(FX_BSTRC("First"));
}
+bool CanReadFromBitStream(const CFX_BitStream* hStream,
+ const FX_SAFE_DWORD& num_bits) {
+ return (num_bits.IsValid() &&
+ hStream->BitsRemaining() >= num_bits.ValueOrDie());
+}
+
} // namespace
// TODO(thestig) Using unique_ptr with ReleaseDeleter is still not ideal.
@@ -4695,10 +4701,10 @@ FX_BOOL CPDF_HintTables::ReadPageHintTable(CFX_BitStream* hStream) {
int nPages = pPageNum ? pPageNum->GetInteger() : 0;
if (nPages < 1)
return FALSE;
+
FX_SAFE_DWORD required_bits = dwDeltaObjectsBits;
required_bits *= pdfium::base::checked_cast<FX_DWORD>(nPages);
- if (!required_bits.IsValid() ||
- hStream->BitsRemaining() < required_bits.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, required_bits))
return FALSE;
for (int i = 0; i < nPages; ++i) {
FX_SAFE_DWORD safeDeltaObj = hStream->GetBits(dwDeltaObjectsBits);
@@ -4708,10 +4714,10 @@ FX_BOOL CPDF_HintTables::ReadPageHintTable(CFX_BitStream* hStream) {
m_dwDeltaNObjsArray.Add(safeDeltaObj.ValueOrDie());
}
hStream->ByteAlign();
+
required_bits = dwDeltaPageLenBits;
required_bits *= pdfium::base::checked_cast<FX_DWORD>(nPages);
- if (!required_bits.IsValid() ||
- hStream->BitsRemaining() < required_bits.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, required_bits))
return FALSE;
CFX_DWordArray dwPageLenArray;
for (int i = 0; i < nPages; ++i) {
@@ -4752,40 +4758,41 @@ FX_BOOL CPDF_HintTables::ReadPageHintTable(CFX_BitStream* hStream) {
dwPageLenArray[nPages - 1]);
}
hStream->ByteAlign();
+
// number of shared objects
required_bits = dwSharedObjBits;
required_bits *= pdfium::base::checked_cast<FX_DWORD>(nPages);
- if (!required_bits.IsValid() ||
- hStream->BitsRemaining() < required_bits.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, required_bits))
return FALSE;
for (int i = 0; i < nPages; i++) {
m_dwNSharedObjsArray.Add(hStream->GetBits(dwSharedObjBits));
}
hStream->ByteAlign();
+
// array of identifier, sizes = nshared_objects
for (int i = 0; i < nPages; i++) {
required_bits = dwSharedIdBits;
required_bits *= m_dwNSharedObjsArray[i];
- if (!required_bits.IsValid() ||
- hStream->BitsRemaining() < required_bits.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, required_bits))
return FALSE;
for (int j = 0; j < m_dwNSharedObjsArray[i]; j++) {
m_dwIdentifierArray.Add(hStream->GetBits(dwSharedIdBits));
}
}
hStream->ByteAlign();
+
for (int i = 0; i < nPages; i++) {
FX_SAFE_DWORD safeSize = m_dwNSharedObjsArray[i];
safeSize *= dwSharedNumeratorBits;
- if (!safeSize.IsValid() || hStream->BitsRemaining() < safeSize.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, safeSize))
return FALSE;
hStream->SkipBits(safeSize.ValueOrDie());
}
hStream->ByteAlign();
+
FX_SAFE_DWORD safeTotalPageLen = pdfium::base::checked_cast<FX_DWORD>(nPages);
safeTotalPageLen *= dwDeltaPageLenBits;
- if (!safeTotalPageLen.IsValid() ||
- hStream->BitsRemaining() < safeTotalPageLen.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, safeTotalPageLen))
return FALSE;
hStream->SkipBits(safeTotalPageLen.ValueOrDie());
hStream->ByteAlign();
@@ -4838,8 +4845,7 @@ FX_BOOL CPDF_HintTables::ReadSharedObjHintTable(CFX_BitStream* hStream,
FX_DWORD dwCurObjLen = 0;
FX_SAFE_DWORD required_bits = dwSharedObjTotal;
required_bits *= dwDeltaGroupLen;
- if (!required_bits.IsValid() ||
- hStream->BitsRemaining() < required_bits.ValueOrDie())
+ if (!CanReadFromBitStream(hStream, required_bits))
return FALSE;
for (int i = 0; i < dwSharedObjTotal; ++i) {
@@ -4973,8 +4979,8 @@ FX_BOOL CPDF_HintTables::LoadHintStream(CPDF_Stream* pHintStream) {
// The header section of shared object hint table is 24 bytes.
// Hint table has at least 60 bytes.
const FX_DWORD MIN_STREAM_LEN = 60;
- if (size < MIN_STREAM_LEN || shared_hint_table_offset < 0 ||
- size < shared_hint_table_offset || !shared_hint_table_offset) {
+ if (size < MIN_STREAM_LEN || shared_hint_table_offset <= 0 ||
+ size < shared_hint_table_offset) {
return FALSE;
}
CFX_BitStream bs;