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Allow self hooking

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This commit is contained in:
LoveSy 2022-11-27 06:36:16 +08:00
parent b7fcd5c915
commit fcba24abe2
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1 changed files with 26 additions and 4 deletions
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30
lsplt/src/main/jni/lsplt.cc
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@ -33,14 +33,27 @@ struct HookInfo : public lsplt::MapInfo {
std::map<uintptr_t, uintptr_t> hooks;
uintptr_t backup;
std::unique_ptr<Elf> elf;
bool self;
[[nodiscard]] bool Match(const RegisterInfo &info) const { return info.inode == inode; }
};
class HookInfos : public std::map<uintptr_t, HookInfo, std::greater<>> {
public:
static auto ScanHookInfo() {
static ino_t kSelfInode = 0;
HookInfos info;
for (auto &map : lsplt::MapInfo::Scan()) {
auto maps = lsplt::MapInfo::Scan();
if (kSelfInode == 0) {
auto self = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
for (auto &map : maps) {
if (self >= map.start && self < map.end) {
kSelfInode = map.inode;
LOGV("self inode = %lu", kSelfInode);
break;
}
}
}
for (auto &map : maps) {
// we basically only care about r-?p entry
// and for offset == 0 it's an ELF header
// and for offset != 0 it's what we hook
@ -48,7 +61,8 @@ public:
if (map.path.empty()) continue;
if (map.path[0] == '[') continue;
auto start = map.start;
info.emplace(start, HookInfo{{std::move(map)}, {}, 0, nullptr});
auto inode = map.inode;
info.emplace(start, HookInfo{{std::move(map)}, {}, 0, nullptr, inode == kSelfInode});
}
return info;
}
@ -96,7 +110,7 @@ public:
// iter.first < addr
auto &info = iter->second;
if (info.end <= addr) return false;
if (!iter->second.backup) {
if (!iter->second.backup && !info.self) {
auto len = info.end - info.start;
// let os find a suitable address
auto *backup_addr = mmap(nullptr, len, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
@ -116,6 +130,14 @@ public:
memcpy(reinterpret_cast<void *>(info.start), backup_addr, len);
info.backup = reinterpret_cast<uintptr_t>(backup_addr);
}
if (info.self) {
// self hooking, no need backup since we are always dirty
auto len = info.end - info.start;
if (!(info.perms & PROT_WRITE)) {
info.perms |= PROT_WRITE;
mprotect(reinterpret_cast<void *>(info.start), len, info.perms);
}
}
auto *the_addr = reinterpret_cast<uintptr_t *>(addr);
auto the_backup = *the_addr;
if (*the_addr != addr) {
@ -128,7 +150,7 @@ public:
} else {
info.hooks.emplace(addr, the_backup);
}
if (info.hooks.empty()) {
if (info.hooks.empty() && !info.self) {
auto len = info.end - info.start;
LOGD("Restore %p from %p", reinterpret_cast<void *>(info.start),
reinterpret_cast<void *>(info.backup));