Object, COFF: Tighten the object file parser
We were a little lax in a few areas:
- We pretended that import libraries were like any old COFF file, they
are not. In fact, they aren't really COFF files at all, we should
probably grow some specialized functionality to handle them smarter.
- Our symbol iterators were more than happy to attempt to go past the
end of the symbol table if you had a symbol with a bad list of
auxiliary symbols.
llvm-svn: 222124
diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index a1fc51a..e25b63b 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -54,7 +54,7 @@
template <typename T>
static std::error_code getObject(const T *&Obj, MemoryBufferRef M,
const void *Ptr,
- const size_t Size = sizeof(T)) {
+ const uint64_t Size = sizeof(T)) {
uintptr_t Addr = uintptr_t(Ptr);
if (std::error_code EC = checkOffset(M, Addr, Size))
return EC;
@@ -101,13 +101,10 @@
const coff_symbol_type *Addr =
reinterpret_cast<const coff_symbol_type *>(Ref.p);
+ assert(!checkOffset(Data, uintptr_t(Addr), sizeof(*Addr)));
#ifndef NDEBUG
// Verify that the symbol points to a valid entry in the symbol table.
uintptr_t Offset = uintptr_t(Addr) - uintptr_t(base());
- if (Offset < getPointerToSymbolTable() ||
- Offset >= getPointerToSymbolTable() +
- (getNumberOfSymbols() * sizeof(coff_symbol_type)))
- report_fatal_error("Symbol was outside of symbol table.");
assert((Offset - getPointerToSymbolTable()) % sizeof(coff_symbol_type) == 0 &&
"Symbol did not point to the beginning of a symbol");
@@ -133,14 +130,15 @@
}
void COFFObjectFile::moveSymbolNext(DataRefImpl &Ref) const {
+ auto End = reinterpret_cast<uintptr_t>(StringTable);
if (SymbolTable16) {
const coff_symbol16 *Symb = toSymb<coff_symbol16>(Ref);
Symb += 1 + Symb->NumberOfAuxSymbols;
- Ref.p = reinterpret_cast<uintptr_t>(Symb);
+ Ref.p = std::min(reinterpret_cast<uintptr_t>(Symb), End);
} else if (SymbolTable32) {
const coff_symbol32 *Symb = toSymb<coff_symbol32>(Ref);
Symb += 1 + Symb->NumberOfAuxSymbols;
- Ref.p = reinterpret_cast<uintptr_t>(Symb);
+ Ref.p = std::min(reinterpret_cast<uintptr_t>(Symb), End);
} else {
llvm_unreachable("no symbol table pointer!");
}
@@ -365,8 +363,12 @@
}
bool COFFObjectFile::isSectionRequiredForExecution(DataRefImpl Ref) const {
- // FIXME: Unimplemented
- return true;
+ // Sections marked 'Info', 'Remove', or 'Discardable' aren't required for
+ // execution.
+ const coff_section *Sec = toSec(Ref);
+ return !(Sec->Characteristics &
+ (COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE |
+ COFF::IMAGE_SCN_MEM_DISCARDABLE));
}
bool COFFObjectFile::isSectionVirtual(DataRefImpl Ref) const {
@@ -375,13 +377,22 @@
}
bool COFFObjectFile::isSectionZeroInit(DataRefImpl Ref) const {
- // FIXME: Unimplemented.
- return false;
+ const coff_section *Sec = toSec(Ref);
+ return Sec->Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
}
bool COFFObjectFile::isSectionReadOnlyData(DataRefImpl Ref) const {
- // FIXME: Unimplemented.
- return false;
+ const coff_section *Sec = toSec(Ref);
+ // Check if it's any sort of data section.
+ if (!(Sec->Characteristics & (COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
+ COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)))
+ return false;
+ // If it's writable or executable or contains code, it isn't read-only data.
+ if (Sec->Characteristics &
+ (COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
+ COFF::IMAGE_SCN_MEM_WRITE))
+ return false;
+ return true;
}
bool COFFObjectFile::sectionContainsSymbol(DataRefImpl SecRef,
@@ -446,15 +457,15 @@
// Initialize the pointer to the symbol table.
std::error_code COFFObjectFile::initSymbolTablePtr() {
if (COFFHeader)
- if (std::error_code EC =
- getObject(SymbolTable16, Data, base() + getPointerToSymbolTable(),
- getNumberOfSymbols() * getSymbolTableEntrySize()))
+ if (std::error_code EC = getObject(
+ SymbolTable16, Data, base() + getPointerToSymbolTable(),
+ (uint64_t)getNumberOfSymbols() * getSymbolTableEntrySize()))
return EC;
if (COFFBigObjHeader)
- if (std::error_code EC =
- getObject(SymbolTable32, Data, base() + getPointerToSymbolTable(),
- getNumberOfSymbols() * getSymbolTableEntrySize()))
+ if (std::error_code EC = getObject(
+ SymbolTable32, Data, base() + getPointerToSymbolTable(),
+ (uint64_t)getNumberOfSymbols() * getSymbolTableEntrySize()))
return EC;
// Find string table. The first four byte of the string table contains the
@@ -681,13 +692,20 @@
}
if ((EC = getObject(SectionTable, Data, base() + CurPtr,
- getNumberOfSections() * sizeof(coff_section))))
+ (uint64_t)getNumberOfSections() * sizeof(coff_section))))
return;
// Initialize the pointer to the symbol table.
- if (getPointerToSymbolTable() != 0)
+ if (getPointerToSymbolTable() != 0) {
if ((EC = initSymbolTablePtr()))
return;
+ } else {
+ // We had better not have any symbols if we don't have a symbol table.
+ if (getNumberOfSymbols() != 0) {
+ EC = object_error::parse_failed;
+ return;
+ }
+ }
// Initialize the pointer to the beginning of the import table.
if ((EC = initImportTablePtr()))
@@ -843,15 +861,15 @@
std::error_code COFFObjectFile::getSection(int32_t Index,
const coff_section *&Result) const {
- // Check for special index values.
+ Result = nullptr;
if (COFF::isReservedSectionNumber(Index))
- Result = nullptr;
- else if (Index > 0 && static_cast<uint32_t>(Index) <= getNumberOfSections())
+ return object_error::success;
+ if (static_cast<uint32_t>(Index) <= getNumberOfSections()) {
// We already verified the section table data, so no need to check again.
Result = SectionTable + (Index - 1);
- else
- return object_error::parse_failed;
- return object_error::success;
+ return object_error::success;
+ }
+ return object_error::parse_failed;
}
std::error_code COFFObjectFile::getString(uint32_t Offset,
@@ -1001,6 +1019,8 @@
symbol_iterator COFFObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
const coff_relocation *R = toRel(Rel);
DataRefImpl Ref;
+ if (R->SymbolTableIndex >= getNumberOfSymbols())
+ return symbol_end();
if (SymbolTable16)
Ref.p = reinterpret_cast<uintptr_t>(SymbolTable16 + R->SymbolTableIndex);
else if (SymbolTable32)