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// Copyright (C) 2016 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qmachparser_p.h"
#include <qendian.h>
#include <mach-o/loader.h>
#include <mach-o/fat.h>
QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
// Whether we include some extra validity checks
// (checks to ensure we don't read out-of-bounds are always included)
static constexpr bool IncludeValidityChecks = true;
#if defined(Q_PROCESSOR_X86_64)
# define MACHO64
static const cpu_type_t my_cputype = CPU_TYPE_X86_64;
#elif defined(Q_PROCESSOR_X86_32)
static const cpu_type_t my_cputype = CPU_TYPE_X86;
#elif defined(Q_PROCESSOR_POWER_64)
# define MACHO64
static const cpu_type_t my_cputype = CPU_TYPE_POWERPC64;
#elif defined(Q_PROCESSOR_POWER_32)
static const cpu_type_t my_cputype = CPU_TYPE_POWERPC;
#elif defined(Q_PROCESSOR_ARM_64)
# define MACHO64
static const cpu_type_t my_cputype = CPU_TYPE_ARM64;
#elif defined(Q_PROCESSOR_ARM)
static const cpu_type_t my_cputype = CPU_TYPE_ARM;
#else
# error "Unknown CPU type"
#endif
#ifdef MACHO64
# undef MACHO64
typedef mach_header_64 my_mach_header;
typedef segment_command_64 my_segment_command;
typedef section_64 my_section;
static const uint32_t my_magic = MH_MAGIC_64;
#else
typedef mach_header my_mach_header;
typedef segment_command my_segment_command;
typedef section my_section;
static const uint32_t my_magic = MH_MAGIC;
#endif
Q_DECL_COLD_FUNCTION
static QLibraryScanResult notfound(const QString &reason, QString *errorString)
{
*errorString = QLibrary::tr("'%1' is not a valid Mach-O binary (%2)")
.arg(*errorString, reason.isEmpty() ? QLibrary::tr("file is corrupt") : reason);
return {};
}
static bool isEncrypted(const my_mach_header *header)
{
auto commandCursor = uintptr_t(header) + sizeof(my_mach_header);
for (uint32_t i = 0; i < header->ncmds; ++i) {
load_command *loadCommand = reinterpret_cast<load_command *>(commandCursor);
if (loadCommand->cmd == LC_ENCRYPTION_INFO || loadCommand->cmd == LC_ENCRYPTION_INFO_64) {
// The layout of encryption_info_command and encryption_info_command_64 is the same
// up until and including cryptid, so we can treat it as encryption_info_command.
auto encryptionInfoCommand = reinterpret_cast<encryption_info_command*>(loadCommand);
return encryptionInfoCommand->cryptid != 0;
}
commandCursor += loadCommand->cmdsize;
}
return false;
}
QLibraryScanResult QMachOParser::parse(const char *m_s, ulong fdlen, QString *errorString)
{
// The minimum size of a Mach-O binary we're interested in.
// It must have a full Mach header, at least one segment and at least one
// section. It's probably useless with just the "qtmetadata" section, but
// it's valid nonetheless.
// A fat binary must have this plus the fat header, of course.
static const size_t MinFileSize = sizeof(my_mach_header) + sizeof(my_segment_command) + sizeof(my_section);
static const size_t MinFatHeaderSize = sizeof(fat_header) + 2 * sizeof(fat_arch);
if (Q_UNLIKELY(fdlen < MinFileSize))
return notfound(QLibrary::tr("file too small"), errorString);
// find out if this is a fat Mach-O binary first
const my_mach_header *header = nullptr;
const fat_header *fat = reinterpret_cast<const fat_header *>(m_s);
if (fat->magic == qToBigEndian(FAT_MAGIC)) {
// find our architecture in the binary
const fat_arch *arch = reinterpret_cast<const fat_arch *>(fat + 1);
if (Q_UNLIKELY(fdlen < MinFatHeaderSize)) {
return notfound(QLibrary::tr("file too small"), errorString);
}
int count = qFromBigEndian(fat->nfat_arch);
if (Q_UNLIKELY(fdlen < sizeof(*fat) + sizeof(*arch) * count))
return notfound(QString(), errorString);
for (int i = 0; i < count; ++i) {
if (arch[i].cputype == qToBigEndian(my_cputype)) {
// ### should we check the CPU subtype? Maybe on ARM?
uint32_t size = qFromBigEndian(arch[i].size);
uint32_t offset = qFromBigEndian(arch[i].offset);
if (Q_UNLIKELY(size > fdlen) || Q_UNLIKELY(offset > fdlen)
|| Q_UNLIKELY(size + offset > fdlen) || Q_UNLIKELY(size < MinFileSize))
return notfound(QString(), errorString);
header = reinterpret_cast<const my_mach_header *>(m_s + offset);
fdlen = size;
break;
}
}
if (!header)
return notfound(QLibrary::tr("no suitable architecture in fat binary"), errorString);
// check the magic again
if (Q_UNLIKELY(header->magic != my_magic))
return notfound(QString(), errorString);
} else {
header = reinterpret_cast<const my_mach_header *>(m_s);
fat = 0;
// check magic
if (header->magic != my_magic)
return notfound(QLibrary::tr("invalid magic %1").arg(qFromBigEndian(header->magic),
8, 16, '0'_L1),
errorString);
}
// from this point on, everything is in host byte order
// (re-)check the CPU type
// ### should we check the CPU subtype? Maybe on ARM?
if (header->cputype != my_cputype) {
if (fat)
return notfound(QString(), errorString);
return notfound(QLibrary::tr("wrong architecture"), errorString);
}
// check the file type
if (Q_UNLIKELY(header->filetype != MH_BUNDLE && header->filetype != MH_DYLIB))
return notfound(QLibrary::tr("not a dynamic library"), errorString);
// find the __TEXT segment, "qtmetadata" section
const my_segment_command *seg = reinterpret_cast<const my_segment_command *>(header + 1);
ulong minsize = sizeof(*header);
for (uint i = 0; i < header->ncmds; ++i,
seg = reinterpret_cast<const my_segment_command *>(reinterpret_cast<const char *>(seg) + seg->cmdsize)) {
// We're sure that the file size includes at least one load command
// but we have to check anyway if we're past the first
if (Q_UNLIKELY(fdlen < minsize + sizeof(load_command)))
return notfound(QString(), errorString);
// cmdsize can't be trusted until validated
// so check it against fdlen anyway
// (these are unsigned operations, with overflow behavior specified in the standard)
minsize += seg->cmdsize;
if (Q_UNLIKELY(fdlen < minsize) || Q_UNLIKELY(fdlen < seg->cmdsize))
return notfound(QString(), errorString);
const uint32_t MyLoadCommand = sizeof(void *) > 4 ? LC_SEGMENT_64 : LC_SEGMENT;
if (seg->cmd != MyLoadCommand)
continue;
// is this the __TEXT segment?
if (strcmp(seg->segname, "__TEXT") == 0) {
const my_section *sect = reinterpret_cast<const my_section *>(seg + 1);
for (uint j = 0; j < seg->nsects; ++j) {
// is this the "qtmetadata" section?
if (strcmp(sect[j].sectname, "qtmetadata") != 0)
continue;
// found it!
if (Q_UNLIKELY(fdlen < sect[j].offset) || Q_UNLIKELY(fdlen < sect[j].size)
|| Q_UNLIKELY(fdlen < sect[j].offset + sect[j].size))
return notfound(QString(), errorString);
if (sect[j].size < sizeof(QPluginMetaData::MagicHeader))
return notfound(QLibrary::tr(".qtmetadata section is too small"), errorString);
const bool binaryIsEncrypted = isEncrypted(header);
qsizetype pos = reinterpret_cast<const char *>(header) - m_s + sect[j].offset;
// We can not read the section data of encrypted libraries until they
// have been dlopened(), so skip validity check if that's the case.
if (IncludeValidityChecks && !binaryIsEncrypted) {
QByteArrayView expectedMagic = QByteArrayView::fromArray(QPluginMetaData::MagicString);
QByteArrayView actualMagic = QByteArrayView(m_s + pos, expectedMagic.size());
if (expectedMagic != actualMagic)
return notfound(QLibrary::tr(".qtmetadata section has incorrect magic"), errorString);
}
pos += sizeof(QPluginMetaData::MagicString);
return { pos, qsizetype(sect[j].size - sizeof(QPluginMetaData::MagicString)), binaryIsEncrypted };
}
}
// other type of segment
seg = reinterpret_cast<const my_segment_command *>(reinterpret_cast<const char *>(seg) + seg->cmdsize);
}
// No .qtmetadata section was found
*errorString = QLibrary::tr("'%1' is not a Qt plugin").arg(*errorString);
return {};
}
QT_END_NAMESPACE
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