Hyprland/src/plugins/HookSystem.cpp
Vaxry 8c64a4bad7
core: move to hyprutils for utils (#6385)
* core: move to hyprutils for utils

Nix: add hyprutils dep

* Meson: add hyprutils dep

* flake.lock: update

---------

Co-authored-by: Mihai Fufezan <mihai@fufexan.net>
2024-06-11 17:17:45 +02:00

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12 KiB
C++

#include "HookSystem.hpp"
#include "../debug/Log.hpp"
#include "../helpers/varlist/VarList.hpp"
#include "../managers/TokenManager.hpp"
#include "../Compositor.hpp"
#define register
#include <udis86.h>
#undef register
#include <sys/mman.h>
#include <unistd.h>
#include <cstring>
#include <fstream>
#include <sys/stat.h>
#include <sys/types.h>
CFunctionHook::CFunctionHook(HANDLE owner, void* source, void* destination) {
m_pSource = source;
m_pDestination = destination;
m_pOwner = owner;
}
CFunctionHook::~CFunctionHook() {
if (m_bActive)
unhook();
}
CFunctionHook::SInstructionProbe CFunctionHook::getInstructionLenAt(void* start) {
ud_t udis;
ud_init(&udis);
ud_set_mode(&udis, 64);
ud_set_syntax(&udis, UD_SYN_ATT);
size_t curOffset = 1;
size_t insSize = 0;
while (true) {
ud_set_input_buffer(&udis, (uint8_t*)start, curOffset);
insSize = ud_disassemble(&udis);
if (insSize != curOffset)
break;
curOffset++;
}
// check for RIP refs
std::string ins;
if (const auto CINS = ud_insn_asm(&udis); CINS)
ins = std::string(CINS);
return {insSize, ins};
}
CFunctionHook::SInstructionProbe CFunctionHook::probeMinimumJumpSize(void* start, size_t min) {
size_t size = 0;
std::string instrs = "";
std::vector<size_t> sizes;
while (size <= min) {
// find info about this instruction
auto probe = getInstructionLenAt((uint8_t*)start + size);
sizes.push_back(probe.len);
size += probe.len;
instrs += probe.assembly + "\n";
}
return {size, instrs, sizes};
}
CFunctionHook::SAssembly CFunctionHook::fixInstructionProbeRIPCalls(const SInstructionProbe& probe) {
SAssembly returns;
// analyze the code and fix what we know how to.
uint64_t currentAddress = (uint64_t)m_pSource;
// actually newline + 1
size_t lastAsmNewline = 0;
// needle for destination binary
size_t currentDestinationOffset = 0;
std::vector<char> finalBytes;
finalBytes.resize(probe.len);
for (auto& len : probe.insSizes) {
// copy original bytes to our finalBytes
for (size_t i = 0; i < len; ++i) {
finalBytes[currentDestinationOffset + i] = *(char*)(currentAddress + i);
}
std::string code = probe.assembly.substr(lastAsmNewline, probe.assembly.find("\n", lastAsmNewline) - lastAsmNewline);
if (code.contains("%rip")) {
CVarList tokens{code, 0, 's'};
size_t plusPresent = tokens[1][0] == '+' ? 1 : 0;
size_t minusPresent = tokens[1][0] == '-' ? 1 : 0;
std::string addr = tokens[1].substr((plusPresent || minusPresent), tokens[1].find("(%rip)") - (plusPresent || minusPresent));
const int32_t OFFSET = (minusPresent ? -1 : 1) * configStringToInt(addr);
if (OFFSET == 0)
return {};
const uint64_t DESTINATION = currentAddress + OFFSET + len;
auto ADDREND = code.find("(%rip)");
auto ADDRSTART = (code.substr(0, ADDREND).find_last_of(' '));
if (ADDREND == std::string::npos || ADDRSTART == std::string::npos)
return {};
const uint64_t PREDICTEDRIP = (uint64_t)m_pTrampolineAddr + currentDestinationOffset + len;
const int32_t NEWRIPOFFSET = DESTINATION - PREDICTEDRIP;
size_t ripOffset = 0;
// find %rip usage offset from beginning
for (int i = len - 4 /* 32-bit */; i > 0; --i) {
if (*(int32_t*)(currentAddress + i) == OFFSET) {
ripOffset = i;
break;
}
}
if (ripOffset == 0)
return {};
// fix offset in the final bytes. This doesn't care about endianness
*(int32_t*)&finalBytes[currentDestinationOffset + ripOffset] = NEWRIPOFFSET;
currentDestinationOffset += len;
} else {
currentDestinationOffset += len;
}
lastAsmNewline = probe.assembly.find("\n", lastAsmNewline) + 1;
currentAddress += len;
}
return {finalBytes};
}
bool CFunctionHook::hook() {
// check for unsupported platforms
#if !defined(__x86_64__)
return false;
#endif
// movabs $0,%rax | jmpq *%rax
// offset for addr: 2
static constexpr uint8_t ABSOLUTE_JMP_ADDRESS[] = {0x48, 0xB8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xE0};
static constexpr size_t ABSOLUTE_JMP_ADDRESS_OFFSET = 2;
// pushq %rax
static constexpr uint8_t PUSH_RAX[] = {0x50};
// popq %rax
static constexpr uint8_t POP_RAX[] = {0x58};
// nop
static constexpr uint8_t NOP = 0x90;
// alloc trampoline
const auto MAX_TRAMPOLINE_SIZE = HOOK_TRAMPOLINE_MAX_SIZE; // we will never need more.
m_pTrampolineAddr = (void*)g_pFunctionHookSystem->getAddressForTrampo();
// probe instructions to be trampolin'd
SInstructionProbe probe;
try {
probe = probeMinimumJumpSize(m_pSource, sizeof(ABSOLUTE_JMP_ADDRESS) + sizeof(PUSH_RAX) + sizeof(POP_RAX));
} catch (std::exception& e) { return false; }
const auto PROBEFIXEDASM = fixInstructionProbeRIPCalls(probe);
if (PROBEFIXEDASM.bytes.size() == 0) {
Debug::log(ERR, "[functionhook] failed, unsupported asm / failed assembling:\n{}", probe.assembly);
return false;
}
const size_t HOOKSIZE = PROBEFIXEDASM.bytes.size();
const size_t ORIGSIZE = probe.len;
const auto TRAMPOLINE_SIZE = sizeof(ABSOLUTE_JMP_ADDRESS) + HOOKSIZE + sizeof(PUSH_RAX);
if (TRAMPOLINE_SIZE > MAX_TRAMPOLINE_SIZE) {
Debug::log(ERR, "[functionhook] failed, not enough space in trampo to alloc:\n{}", probe.assembly);
return false;
}
m_pOriginalBytes = malloc(ORIGSIZE);
memcpy(m_pOriginalBytes, m_pSource, ORIGSIZE);
// populate trampoline
memcpy(m_pTrampolineAddr, PROBEFIXEDASM.bytes.data(), HOOKSIZE); // first, original but fixed func bytes
memcpy((uint8_t*)m_pTrampolineAddr + HOOKSIZE, PUSH_RAX, sizeof(PUSH_RAX)); // then, pushq %rax
memcpy((uint8_t*)m_pTrampolineAddr + HOOKSIZE + sizeof(PUSH_RAX), ABSOLUTE_JMP_ADDRESS, sizeof(ABSOLUTE_JMP_ADDRESS)); // then, jump to source
// fixup trampoline addr
*(uint64_t*)((uint8_t*)m_pTrampolineAddr + TRAMPOLINE_SIZE - sizeof(ABSOLUTE_JMP_ADDRESS) + ABSOLUTE_JMP_ADDRESS_OFFSET) =
(uint64_t)((uint8_t*)m_pSource + sizeof(ABSOLUTE_JMP_ADDRESS));
// make jump to hk
const auto PAGESIZE_VAR = sysconf(_SC_PAGE_SIZE);
const uint8_t* PROTSTART = (uint8_t*)m_pSource - ((uint64_t)m_pSource % PAGESIZE_VAR);
const size_t PROTLEN = std::ceil((float)(ORIGSIZE + ((uint64_t)m_pSource - (uint64_t)PROTSTART)) / (float)PAGESIZE_VAR) * PAGESIZE_VAR;
mprotect((uint8_t*)PROTSTART, PROTLEN, PROT_READ | PROT_WRITE | PROT_EXEC);
memcpy((uint8_t*)m_pSource, ABSOLUTE_JMP_ADDRESS, sizeof(ABSOLUTE_JMP_ADDRESS));
// make popq %rax and NOP all remaining
memcpy((uint8_t*)m_pSource + sizeof(ABSOLUTE_JMP_ADDRESS), POP_RAX, sizeof(POP_RAX));
size_t currentOp = sizeof(ABSOLUTE_JMP_ADDRESS) + sizeof(POP_RAX);
memset((uint8_t*)m_pSource + currentOp, NOP, ORIGSIZE - currentOp);
// fixup jump addr
*(uint64_t*)((uint8_t*)m_pSource + ABSOLUTE_JMP_ADDRESS_OFFSET) = (uint64_t)(m_pDestination);
// revert mprot
mprotect((uint8_t*)PROTSTART, PROTLEN, PROT_READ | PROT_EXEC);
// set original addr to trampo addr
m_pOriginal = m_pTrampolineAddr;
m_bActive = true;
m_iHookLen = ORIGSIZE;
m_iTrampoLen = TRAMPOLINE_SIZE;
return true;
}
bool CFunctionHook::unhook() {
// check for unsupported platforms
#if !defined(__x86_64__)
return false;
#endif
if (!m_bActive)
return false;
// allow write to src
mprotect((uint8_t*)m_pSource - ((uint64_t)m_pSource) % sysconf(_SC_PAGE_SIZE), sysconf(_SC_PAGE_SIZE), PROT_READ | PROT_WRITE | PROT_EXEC);
// write back original bytes
memcpy(m_pSource, m_pOriginalBytes, m_iHookLen);
// revert mprot
mprotect((uint8_t*)m_pSource - ((uint64_t)m_pSource) % sysconf(_SC_PAGE_SIZE), sysconf(_SC_PAGE_SIZE), PROT_READ | PROT_EXEC);
// reset vars
m_bActive = false;
m_iHookLen = 0;
m_iTrampoLen = 0;
m_pTrampolineAddr = nullptr; // no unmapping, it's managed by the HookSystem
m_pOriginalBytes = nullptr;
free(m_pOriginalBytes);
return true;
}
CFunctionHook* CHookSystem::initHook(HANDLE owner, void* source, void* destination) {
return m_vHooks.emplace_back(std::make_unique<CFunctionHook>(owner, source, destination)).get();
}
bool CHookSystem::removeHook(CFunctionHook* hook) {
std::erase_if(m_vHooks, [&](const auto& other) { return other.get() == hook; });
return true; // todo: make false if not found
}
void CHookSystem::removeAllHooksFrom(HANDLE handle) {
std::erase_if(m_vHooks, [&](const auto& other) { return other->m_pOwner == handle; });
}
static uintptr_t seekNewPageAddr() {
const uint64_t PAGESIZE_VAR = sysconf(_SC_PAGE_SIZE);
auto MAPS = std::ifstream("/proc/self/maps");
uint64_t lastStart = 0, lastEnd = 0;
std::string line;
while (std::getline(MAPS, line)) {
CVarList props{line, 0, 's', true};
uint64_t start = 0, end = 0;
if (props[0].empty()) {
Debug::log(WARN, "seekNewPageAddr: unexpected line in self maps");
continue;
}
CVarList startEnd{props[0], 0, '-', true};
try {
start = std::stoull(startEnd[0], nullptr, 16);
end = std::stoull(startEnd[1], nullptr, 16);
} catch (std::exception& e) {
Debug::log(WARN, "seekNewPageAddr: unexpected line in self maps: {}", line);
continue;
}
Debug::log(LOG, "seekNewPageAddr: page 0x{:x} - 0x{:x}", start, end);
if (lastStart == 0) {
lastStart = start;
lastEnd = end;
continue;
}
if (start - lastEnd > PAGESIZE_VAR * 2) {
Debug::log(LOG, "seekNewPageAddr: found gap: 0x{:x}-0x{:x} ({} bytes)", lastEnd, start, start - lastEnd);
MAPS.close();
return lastEnd;
}
lastStart = start;
lastEnd = end;
}
MAPS.close();
return 0;
}
uint64_t CHookSystem::getAddressForTrampo() {
// yes, technically this creates a memory leak of 64B every hook creation. But I don't care.
// tracking all the users of the memory would be painful.
// Nobody will hook 100k times, and even if, that's only 6.4 MB. Nothing.
SAllocatedPage* page = nullptr;
for (auto& p : pages) {
if (p.used + HOOK_TRAMPOLINE_MAX_SIZE > p.len)
continue;
page = &p;
break;
}
if (!page)
page = &pages.emplace_back();
if (!page->addr) {
// allocate it
Debug::log(LOG, "getAddressForTrampo: Allocating new page for hooks");
const uint64_t PAGESIZE_VAR = sysconf(_SC_PAGE_SIZE);
const auto BASEPAGEADDR = seekNewPageAddr();
for (int attempt = 0; attempt < 2; ++attempt) {
for (int i = 0; i <= 2; ++i) {
const auto PAGEADDR = BASEPAGEADDR + i * PAGESIZE_VAR;
page->addr = (uint64_t)mmap((void*)PAGEADDR, PAGESIZE_VAR, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
page->len = PAGESIZE_VAR;
page->used = 0;
Debug::log(LOG, "Attempted to allocate 0x{:x}, got 0x{:x}", PAGEADDR, page->addr);
if (page->addr == (uint64_t)MAP_FAILED)
continue;
if (page->addr != PAGEADDR && attempt == 0) {
munmap((void*)page->addr, PAGESIZE_VAR);
page->addr = 0;
page->len = 0;
continue;
}
break;
}
if (page->addr)
break;
}
}
const auto ADDRFORCONSUMER = page->addr + page->used;
page->used += HOOK_TRAMPOLINE_MAX_SIZE;
Debug::log(LOG, "getAddressForTrampo: Returning addr 0x{:x} for page at 0x{:x}", ADDRFORCONSUMER, page->addr);
return ADDRFORCONSUMER;
}