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[DebugInfo] Do not hang when parsing a malformed .debug_pub* section. 

The parsing method did not check reading errors and might easily fall
into an infinite loop on an invalid input because of that.

Differential Revision: https://reviews.llvm.org/D83049
This commit is contained in:
Igor Kudrin 2020-07-09 19:15:11 +07:00
parent a86ce06faf
commit 68f5a8b204
7 changed files with 108 additions and 39 deletions
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4
lld/ELF/DWARF.h
View File

@ -56,11 +56,11 @@ public:
return addrSection;
}
const llvm::DWARFSection &getGnuPubnamesSection() const override {
const LLDDWARFSection &getGnuPubnamesSection() const override {
return gnuPubnamesSection;
}
const llvm::DWARFSection &getGnuPubtypesSection() const override {
const LLDDWARFSection &getGnuPubtypesSection() const override {
return gnuPubtypesSection;
}

11
lld/ELF/SyntheticSections.cpp
View File

@ -2705,12 +2705,15 @@ template <class ELFT>
static std::vector<GdbIndexSection::NameAttrEntry>
readPubNamesAndTypes(const LLDDwarfObj<ELFT> &obj,
const std::vector<GdbIndexSection::CuEntry> &cus) {
const DWARFSection &pubNames = obj.getGnuPubnamesSection();
const DWARFSection &pubTypes = obj.getGnuPubtypesSection();
const LLDDWARFSection &pubNames = obj.getGnuPubnamesSection();
const LLDDWARFSection &pubTypes = obj.getGnuPubtypesSection();
std::vector<GdbIndexSection::NameAttrEntry> ret;
for (const DWARFSection *pub : {&pubNames, &pubTypes}) {
DWARFDebugPubTable table(obj, *pub, config->isLE, true);
for (const LLDDWARFSection *pub : {&pubNames, &pubTypes}) {
DWARFDataExtractor data(obj, *pub, config->isLE, config->wordsize);
DWARFDebugPubTable table;
if (Error e = table.extract(data, /*GnuStyle=*/true))
warn(toString(pub->sec) + ": " + toString(std::move(e)));
for (const DWARFDebugPubTable::Set &set : table.getData()) {
// The value written into the constant pool is kind << 24 | cuIndex. As we
// don't know how many compilation units precede this object to compute

26
lld/test/ELF/gdb-index-invalid-pubnames.s Normal file
View File

@ -0,0 +1,26 @@
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t
# RUN: ld.lld --gdb-index %t -o /dev/null 2>&1 | FileCheck %s
# CHECK: warning: {{.*}}(.debug_gnu_pubnames): unexpected end of data at offset 0x1 while reading [0x0, 0x4)
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)
.section .debug_info,"",@progbits
.LCUBegin:
.long .LUnitEnd-.LUnitBegin # Length of Unit
.LUnitBegin:
.short 4 # DWARF version number
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 8 # Address Size (in bytes)
.byte 1 # Abbrev [1] DW_TAG_compile_unit
.LUnitEnd:
.section .debug_gnu_pubnames,"",@progbits
.byte 0

8
llvm/include/llvm/DebugInfo/DWARF/DWARFDebugPubTable.h
View File

@ -12,6 +12,7 @@
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
#include "llvm/DebugInfo/DWARF/DWARFObject.h"
#include <cstdint>
#include <vector>
@ -67,11 +68,12 @@ private:
/// gnu styled tables contains additional information.
/// This flag determines whether or not section we parse is debug_gnu* table.
bool GnuStyle;
bool GnuStyle = false;
public:
DWARFDebugPubTable(const DWARFObject &Obj, const DWARFSection &Sec,
bool LittleEndian, bool GnuStyle);
DWARFDebugPubTable() = default;
Error extract(DWARFDataExtractor Data, bool GnuStyle);
void dump(raw_ostream &OS) const;

42
llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
View File

@ -336,6 +336,14 @@ static void dumpLoclistsSection(raw_ostream &OS, DIDumpOptions DumpOpts,
}
}
static void dumpPubTableSection(raw_ostream &OS, DIDumpOptions DumpOpts,
DWARFDataExtractor Data, bool GnuStyle) {
DWARFDebugPubTable Table;
if (Error E = Table.extract(Data, GnuStyle))
DumpOpts.RecoverableErrorHandler(std::move(E));
Table.dump(OS);
}
void DWARFContext::dump(
raw_ostream &OS, DIDumpOptions DumpOpts,
std::array<Optional<uint64_t>, DIDT_ID_Count> DumpOffsets) {
@ -626,26 +634,32 @@ void DWARFContext::dump(
}
if (shouldDump(Explicit, ".debug_pubnames", DIDT_ID_DebugPubnames,
DObj->getPubnamesSection().Data))
DWARFDebugPubTable(*DObj, DObj->getPubnamesSection(), isLittleEndian(), false)
.dump(OS);
DObj->getPubnamesSection().Data)) {
DWARFDataExtractor PubTableData(*DObj, DObj->getPubnamesSection(),
isLittleEndian(), 0);
dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/false);
}
if (shouldDump(Explicit, ".debug_pubtypes", DIDT_ID_DebugPubtypes,
DObj->getPubtypesSection().Data))
DWARFDebugPubTable(*DObj, DObj->getPubtypesSection(), isLittleEndian(), false)
.dump(OS);
DObj->getPubtypesSection().Data)) {
DWARFDataExtractor PubTableData(*DObj, DObj->getPubtypesSection(),
isLittleEndian(), 0);
dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/false);
}
if (shouldDump(Explicit, ".debug_gnu_pubnames", DIDT_ID_DebugGnuPubnames,
DObj->getGnuPubnamesSection().Data))
DWARFDebugPubTable(*DObj, DObj->getGnuPubnamesSection(), isLittleEndian(),
true /* GnuStyle */)
.dump(OS);
DObj->getGnuPubnamesSection().Data)) {
DWARFDataExtractor PubTableData(*DObj, DObj->getGnuPubnamesSection(),
isLittleEndian(), 0);
dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/true);
}
if (shouldDump(Explicit, ".debug_gnu_pubtypes", DIDT_ID_DebugGnuPubtypes,
DObj->getGnuPubtypesSection().Data))
DWARFDebugPubTable(*DObj, DObj->getGnuPubtypesSection(), isLittleEndian(),
true /* GnuStyle */)
.dump(OS);
DObj->getGnuPubtypesSection().Data)) {
DWARFDataExtractor PubTableData(*DObj, DObj->getGnuPubtypesSection(),
isLittleEndian(), 0);
dumpPubTableSection(OS, DumpOpts, PubTableData, /*GnuStyle=*/true);
}
if (shouldDump(Explicit, ".debug_str_offsets", DIDT_ID_DebugStrOffsets,
DObj->getStrOffsetsSection().Data))

30
llvm/lib/DebugInfo/DWARF/DWARFDebugPubTable.cpp
View File

@ -18,34 +18,32 @@
using namespace llvm;
using namespace dwarf;
DWARFDebugPubTable::DWARFDebugPubTable(const DWARFObject &Obj,
const DWARFSection &Sec,
bool LittleEndian, bool GnuStyle)
: GnuStyle(GnuStyle) {
DWARFDataExtractor PubNames(Obj, Sec, LittleEndian, 0);
uint64_t Offset = 0;
while (PubNames.isValidOffset(Offset)) {
Error DWARFDebugPubTable::extract(DWARFDataExtractor Data, bool GnuStyle) {
this->GnuStyle = GnuStyle;
Sets.clear();
DataExtractor::Cursor C(0);
while (C && Data.isValidOffset(C.tell())) {
Sets.push_back({});
Set &SetData = Sets.back();
std::tie(SetData.Length, SetData.Format) =
PubNames.getInitialLength(&Offset);
std::tie(SetData.Length, SetData.Format) = Data.getInitialLength(C);
const unsigned OffsetSize = dwarf::getDwarfOffsetByteSize(SetData.Format);
SetData.Version = PubNames.getU16(&Offset);
SetData.Offset = PubNames.getRelocatedValue(OffsetSize, &Offset);
SetData.Size = PubNames.getUnsigned(&Offset, OffsetSize);
SetData.Version = Data.getU16(C);
SetData.Offset = Data.getRelocatedValue(C, OffsetSize);
SetData.Size = Data.getUnsigned(C, OffsetSize);
while (Offset < Sec.Data.size()) {
uint64_t DieRef = PubNames.getUnsigned(&Offset, OffsetSize);
while (C) {
uint64_t DieRef = Data.getUnsigned(C, OffsetSize);
if (DieRef == 0)
break;
uint8_t IndexEntryValue = GnuStyle ? PubNames.getU8(&Offset) : 0;
StringRef Name = PubNames.getCStrRef(&Offset);
uint8_t IndexEntryValue = GnuStyle ? Data.getU8(C) : 0;
StringRef Name = Data.getCStrRef(C);
SetData.Entries.push_back(
{DieRef, PubIndexEntryDescriptor(IndexEntryValue), Name});
}
}
return C.takeError();
}
void DWARFDebugPubTable::dump(raw_ostream &OS) const {

26
llvm/test/tools/llvm-dwarfdump/X86/debug_pub_tables_invalid.s Normal file
View File

@ -0,0 +1,26 @@
# RUN: llvm-mc -triple x86_64 %s -filetype=obj -o %t
# RUN: not llvm-dwarfdump -v %t 2>&1 | FileCheck %s
# CHECK: .debug_pubnames contents:
# CHECK-NEXT: error: unexpected end of data at offset 0x1 while reading [0x0, 0x4)
# CHECK: .debug_pubtypes contents:
# CHECK-NEXT: error: unexpected end of data at offset 0x1 while reading [0x0, 0x4)
# CHECK: .debug_gnu_pubnames contents:
# CHECK-NEXT: error: unexpected end of data at offset 0x1 while reading [0x0, 0x4)
# CHECK: .debug_gnu_pubtypes contents:
# CHECK-NEXT: error: unexpected end of data at offset 0x1 while reading [0x0, 0x4)
.section .debug_pubnames,"",@progbits
.byte 0
.section .debug_pubtypes,"",@progbits
.byte 0
.section .debug_gnu_pubnames,"",@progbits
.byte 0
.section .debug_gnu_pubtypes,"",@progbits
.byte 0