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Guard against unsigned overflow. #4093

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Merged
merged 2 commits into from
Mar 21, 2022
Merged

Guard against unsigned overflow. #4093

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c22b71b
clang-format LLDBMemoryReader
adrian-prantl Mar 18, 2022
df5acb7
Guard against unsigned overflow.
adrian-prantl Mar 18, 2022
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78 changes: 44 additions & 34 deletions lldb/source/Plugins/LanguageRuntime/Swift/LLDBMemoryReader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -196,9 +196,9 @@ LLDBMemoryReader::resolvePointer(swift::remote::RemoteAddress address,
// We haven't registered the image that contains the pointer.
if (pair_iterator == m_range_module_map.end()) {
LLDB_LOG(log,
"[MemoryReader] Could not resolve find module containing pointer "
"{0:x} read from {1:x}.",
readValue, address.getAddressData());
"[MemoryReader] Could not resolve find module containing pointer "
"{0:x} read from {1:x}.",
readValue, address.getAddressData());
return process_pointer;
}

Expand Down Expand Up @@ -230,10 +230,18 @@ LLDBMemoryReader::resolvePointer(swift::remote::RemoteAddress address,

bool LLDBMemoryReader::readBytes(swift::remote::RemoteAddress address,
uint8_t *dest, uint64_t size) {
Log *log = GetLog(LLDBLog::Types);
if (m_local_buffer) {
bool overflow = false;
auto addr = address.getAddressData();
auto end = llvm::SaturatingAdd(addr, size, &overflow);
if (overflow) {
LLDB_LOGV(log, "[MemoryReader] address {0:x} + size {1} overflows", addr,
size);
return false;
}
if (addr >= *m_local_buffer &&
addr + size <= *m_local_buffer + m_local_buffer_size) {
end <= *m_local_buffer + m_local_buffer_size) {
// If this crashes, the assumptions stated in
// GetDynamicTypeAndAddress_Protocol() most likely no longer
// hold.
Expand All @@ -242,16 +250,13 @@ bool LLDBMemoryReader::readBytes(swift::remote::RemoteAddress address,
}
}

Log *log = GetLog(LLDBLog::Types);

LLDB_LOGV(log, "[MemoryReader] asked to read {0} bytes at address {1:x}",
size, address.getAddressData());
llvm::Optional<Address> maybeAddr =
resolveRemoteAddressFromSymbolObjectFile(address.getAddressData());

if (!maybeAddr)
maybeAddr =
resolveRemoteAddress(address.getAddressData());
if (!maybeAddr)
maybeAddr = resolveRemoteAddress(address.getAddressData());

if (!maybeAddr) {
LLDB_LOGV(log, "[MemoryReader] could not resolve address {0:x}",
Expand All @@ -276,7 +281,7 @@ bool LLDBMemoryReader::readBytes(swift::remote::RemoteAddress address,
}
Target &target(m_process.GetTarget());
Status error;
// We only want to allow the file-cache optimization if we resolved the
// We only want to allow the file-cache optimization if we resolved the
// address to section + offset.
const bool force_live_memory =
!readMetadataFromFileCacheEnabled() || !addr.IsSectionOffset();
Expand Down Expand Up @@ -309,27 +314,26 @@ bool LLDBMemoryReader::readString(swift::remote::RemoteAddress address,
std::string &dest) {
Log *log = GetLog(LLDBLog::Types);

auto format_string = [](const std::string &dest) {
StreamString stream;
for (auto c : dest) {
if (c >= 32 && c <= 127) {
stream << c;
} else {
stream << "\\0";
stream.PutHex8(c);
}
auto format_string = [](const std::string &dest) {
StreamString stream;
for (auto c : dest) {
if (c >= 32 && c <= 127) {
stream << c;
} else {
stream << "\\0";
stream.PutHex8(c);
}
return std::string(stream.GetData());
};
}
return std::string(stream.GetData());
};
LLDB_LOGV(log, "[MemoryReader] asked to read string data at address {0:x}",
address.getAddressData());

llvm::Optional<Address> maybeAddr =
resolveRemoteAddressFromSymbolObjectFile(address.getAddressData());

if (!maybeAddr)
maybeAddr =
resolveRemoteAddress(address.getAddressData());
if (!maybeAddr)
maybeAddr = resolveRemoteAddress(address.getAddressData());

if (!maybeAddr) {
LLDB_LOGV(log, "[MemoryReader] could not resolve address {0:x}",
Expand All @@ -344,15 +348,15 @@ bool LLDBMemoryReader::readString(swift::remote::RemoteAddress address,
LLDB_LOGV(log, "[MemoryReader] Reading memory from symbol rich binary");

dest = object_file->GetCStrFromSection(section.get(), addr.GetOffset());
LLDB_LOGV(log, "[MemoryReader] memory read returned string: \"{0}\"",
format_string(dest));
LLDB_LOGV(log, "[MemoryReader] memory read returned string: \"{0}\"",
format_string(dest));
return true;
}
}

Target &target(m_process.GetTarget());
Status error;
// We only want to allow the file-cache optimization if we resolved the
// We only want to allow the file-cache optimization if we resolved the
// address to section + offset.
const bool force_live_memory =
!readMetadataFromFileCacheEnabled() || !addr.IsSectionOffset();
Expand Down Expand Up @@ -381,7 +385,8 @@ void LLDBMemoryReader::popLocalBuffer() {
}

llvm::Optional<std::pair<uint64_t, uint64_t>>
LLDBMemoryReader::addModuleToAddressMap(ModuleSP module, bool register_symbol_obj_file) {
LLDBMemoryReader::addModuleToAddressMap(ModuleSP module,
bool register_symbol_obj_file) {
if (!readMetadataFromFileCacheEnabled())
return {};

Expand All @@ -402,11 +407,10 @@ LLDBMemoryReader::addModuleToAddressMap(ModuleSP module, bool register_symbol_ob

#ifndef NDEBUG
static std::initializer_list<uint64_t> objc_bits = {
SWIFT_ABI_ARM_IS_OBJC_BIT,
SWIFT_ABI_X86_64_IS_OBJC_BIT,
SWIFT_ABI_ARM_IS_OBJC_BIT, SWIFT_ABI_X86_64_IS_OBJC_BIT,
SWIFT_ABI_ARM64_IS_OBJC_BIT};

for (auto objc_bit : objc_bits)
for (auto objc_bit : objc_bits)
assert((module_start_address & objc_bit) != objc_bit &&
"LLDB file address bit clashes with an obj-c bit!");
#endif
Expand Down Expand Up @@ -523,7 +527,9 @@ LLDBMemoryReader::resolveRemoteAddress(uint64_t address) const {
return resolved;
}

llvm::Optional<Address> LLDBMemoryReader::resolveRemoteAddressFromSymbolObjectFile(uint64_t address) const {
llvm::Optional<Address>
LLDBMemoryReader::resolveRemoteAddressFromSymbolObjectFile(
uint64_t address) const {
Log *log(GetLog(LLDBLog::Types));

if (!m_process.GetTarget().GetSwiftReadMetadataFromDSYM())
Expand Down Expand Up @@ -555,8 +561,12 @@ llvm::Optional<Address> LLDBMemoryReader::resolveRemoteAddressFromSymbolObjectFi
file_address, object_file->GetFileSpec().GetFilename());
return {};
}

if (!resolved.GetSection()->GetParent()->GetName().GetStringRef().contains_insensitive("DWARF")) {

if (!resolved.GetSection()
->GetParent()
->GetName()
.GetStringRef()
.contains_insensitive("DWARF")) {
auto *main_object_file = module->GetObjectFile();
resolved = Address(file_address, main_object_file->GetSectionList());
}
Expand Down