| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "environment.h" |
| |
| #include <inttypes.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sys/utsname.h> |
| |
| #include <limits> |
| #include <set> |
| #include <unordered_map> |
| #include <vector> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/parseint.h> |
| #include <android-base/strings.h> |
| #include <android-base/stringprintf.h> |
| #include <procinfo/process.h> |
| |
| #if defined(__ANDROID__) |
| #include <sys/system_properties.h> |
| #endif |
| |
| #include "read_elf.h" |
| #include "thread_tree.h" |
| #include "utils.h" |
| |
| class LineReader { |
| public: |
| explicit LineReader(FILE* fp) : fp_(fp), buf_(nullptr), bufsize_(0) { |
| } |
| |
| ~LineReader() { |
| free(buf_); |
| fclose(fp_); |
| } |
| |
| char* ReadLine() { |
| if (getline(&buf_, &bufsize_, fp_) != -1) { |
| return buf_; |
| } |
| return nullptr; |
| } |
| |
| size_t MaxLineSize() { |
| return bufsize_; |
| } |
| |
| private: |
| FILE* fp_; |
| char* buf_; |
| size_t bufsize_; |
| }; |
| |
| std::vector<int> GetOnlineCpus() { |
| std::vector<int> result; |
| FILE* fp = fopen("/sys/devices/system/cpu/online", "re"); |
| if (fp == nullptr) { |
| PLOG(ERROR) << "can't open online cpu information"; |
| return result; |
| } |
| |
| LineReader reader(fp); |
| char* line; |
| if ((line = reader.ReadLine()) != nullptr) { |
| result = GetCpusFromString(line); |
| } |
| CHECK(!result.empty()) << "can't get online cpu information"; |
| return result; |
| } |
| |
| std::vector<int> GetCpusFromString(const std::string& s) { |
| std::set<int> cpu_set; |
| bool have_dash = false; |
| const char* p = s.c_str(); |
| char* endp; |
| int last_cpu; |
| int cpu; |
| // Parse line like: 0,1-3, 5, 7-8 |
| while ((cpu = static_cast<int>(strtol(p, &endp, 10))) != 0 || endp != p) { |
| if (have_dash && !cpu_set.empty()) { |
| for (int t = last_cpu + 1; t < cpu; ++t) { |
| cpu_set.insert(t); |
| } |
| } |
| have_dash = false; |
| cpu_set.insert(cpu); |
| last_cpu = cpu; |
| p = endp; |
| while (!isdigit(*p) && *p != '\0') { |
| if (*p == '-') { |
| have_dash = true; |
| } |
| ++p; |
| } |
| } |
| return std::vector<int>(cpu_set.begin(), cpu_set.end()); |
| } |
| |
| static std::vector<KernelMmap> GetLoadedModules() { |
| std::vector<KernelMmap> result; |
| FILE* fp = fopen("/proc/modules", "re"); |
| if (fp == nullptr) { |
| // There is no /proc/modules on Android devices, so we don't print error if failed to open it. |
| PLOG(DEBUG) << "failed to open file /proc/modules"; |
| return result; |
| } |
| LineReader reader(fp); |
| char* line; |
| while ((line = reader.ReadLine()) != nullptr) { |
| // Parse line like: nf_defrag_ipv6 34768 1 nf_conntrack_ipv6, Live 0xffffffffa0fe5000 |
| char name[reader.MaxLineSize()]; |
| uint64_t addr; |
| if (sscanf(line, "%s%*lu%*u%*s%*s 0x%" PRIx64, name, &addr) == 2) { |
| KernelMmap map; |
| map.name = name; |
| map.start_addr = addr; |
| result.push_back(map); |
| } |
| } |
| bool all_zero = true; |
| for (const auto& map : result) { |
| if (map.start_addr != 0) { |
| all_zero = false; |
| } |
| } |
| if (all_zero) { |
| LOG(DEBUG) << "addresses in /proc/modules are all zero, so ignore kernel modules"; |
| return std::vector<KernelMmap>(); |
| } |
| return result; |
| } |
| |
| static void GetAllModuleFiles(const std::string& path, |
| std::unordered_map<std::string, std::string>* module_file_map) { |
| for (const auto& name : GetEntriesInDir(path)) { |
| std::string entry_path = path + "/" + name; |
| if (IsRegularFile(entry_path) && android::base::EndsWith(name, ".ko")) { |
| std::string module_name = name.substr(0, name.size() - 3); |
| std::replace(module_name.begin(), module_name.end(), '-', '_'); |
| module_file_map->insert(std::make_pair(module_name, entry_path)); |
| } else if (IsDir(entry_path)) { |
| GetAllModuleFiles(entry_path, module_file_map); |
| } |
| } |
| } |
| |
| static std::vector<KernelMmap> GetModulesInUse() { |
| utsname uname_buf; |
| if (TEMP_FAILURE_RETRY(uname(&uname_buf)) != 0) { |
| PLOG(ERROR) << "uname() failed"; |
| return std::vector<KernelMmap>(); |
| } |
| std::string linux_version = uname_buf.release; |
| std::string module_dirpath = "/lib/modules/" + linux_version + "/kernel"; |
| std::unordered_map<std::string, std::string> module_file_map; |
| GetAllModuleFiles(module_dirpath, &module_file_map); |
| // TODO: There is no /proc/modules or /lib/modules on Android, find methods work on it. |
| std::vector<KernelMmap> module_mmaps = GetLoadedModules(); |
| for (auto& module : module_mmaps) { |
| auto it = module_file_map.find(module.name); |
| if (it != module_file_map.end()) { |
| module.filepath = it->second; |
| } |
| } |
| return module_mmaps; |
| } |
| |
| void GetKernelAndModuleMmaps(KernelMmap* kernel_mmap, std::vector<KernelMmap>* module_mmaps) { |
| kernel_mmap->name = DEFAULT_KERNEL_MMAP_NAME; |
| kernel_mmap->start_addr = 0; |
| kernel_mmap->filepath = kernel_mmap->name; |
| *module_mmaps = GetModulesInUse(); |
| for (auto& map : *module_mmaps) { |
| if (map.filepath.empty()) { |
| map.filepath = "[" + map.name + "]"; |
| } |
| } |
| |
| if (module_mmaps->size() == 0) { |
| kernel_mmap->len = std::numeric_limits<uint64_t>::max() - kernel_mmap->start_addr; |
| } else { |
| std::sort( |
| module_mmaps->begin(), module_mmaps->end(), |
| [](const KernelMmap& m1, const KernelMmap& m2) { return m1.start_addr < m2.start_addr; }); |
| // When not having enough privilege, all addresses are read as 0. |
| if (kernel_mmap->start_addr == (*module_mmaps)[0].start_addr) { |
| kernel_mmap->len = 0; |
| } else { |
| kernel_mmap->len = (*module_mmaps)[0].start_addr - kernel_mmap->start_addr - 1; |
| } |
| for (size_t i = 0; i + 1 < module_mmaps->size(); ++i) { |
| if ((*module_mmaps)[i].start_addr == (*module_mmaps)[i + 1].start_addr) { |
| (*module_mmaps)[i].len = 0; |
| } else { |
| (*module_mmaps)[i].len = |
| (*module_mmaps)[i + 1].start_addr - (*module_mmaps)[i].start_addr - 1; |
| } |
| } |
| module_mmaps->back().len = |
| std::numeric_limits<uint64_t>::max() - module_mmaps->back().start_addr; |
| } |
| } |
| |
| static bool ReadThreadNameAndPid(pid_t tid, std::string* comm, pid_t* pid) { |
| android::procinfo::ProcessInfo procinfo; |
| if (!android::procinfo::GetProcessInfo(tid, &procinfo)) { |
| return false; |
| } |
| if (comm != nullptr) { |
| *comm = procinfo.name; |
| } |
| if (pid != nullptr) { |
| *pid = procinfo.pid; |
| } |
| return true; |
| } |
| |
| std::vector<pid_t> GetThreadsInProcess(pid_t pid) { |
| std::vector<pid_t> result; |
| android::procinfo::GetProcessTids(pid, &result); |
| return result; |
| } |
| |
| bool IsThreadAlive(pid_t tid) { |
| return IsDir(android::base::StringPrintf("/proc/%d", tid)); |
| } |
| |
| bool GetProcessForThread(pid_t tid, pid_t* pid) { |
| return ReadThreadNameAndPid(tid, nullptr, pid); |
| } |
| |
| bool GetThreadName(pid_t tid, std::string* name) { |
| return ReadThreadNameAndPid(tid, name, nullptr); |
| } |
| |
| std::vector<pid_t> GetAllProcesses() { |
| std::vector<pid_t> result; |
| std::vector<std::string> entries = GetEntriesInDir("/proc"); |
| for (const auto& entry : entries) { |
| pid_t pid; |
| if (!android::base::ParseInt(entry.c_str(), &pid, 0)) { |
| continue; |
| } |
| result.push_back(pid); |
| } |
| return result; |
| } |
| |
| bool GetThreadMmapsInProcess(pid_t pid, std::vector<ThreadMmap>* thread_mmaps) { |
| std::string map_file = android::base::StringPrintf("/proc/%d/maps", pid); |
| FILE* fp = fopen(map_file.c_str(), "re"); |
| if (fp == nullptr) { |
| PLOG(DEBUG) << "can't open file " << map_file; |
| return false; |
| } |
| thread_mmaps->clear(); |
| LineReader reader(fp); |
| char* line; |
| while ((line = reader.ReadLine()) != nullptr) { |
| // Parse line like: 00400000-00409000 r-xp 00000000 fc:00 426998 /usr/lib/gvfs/gvfsd-http |
| uint64_t start_addr, end_addr, pgoff; |
| char type[reader.MaxLineSize()]; |
| char execname[reader.MaxLineSize()]; |
| strcpy(execname, ""); |
| if (sscanf(line, "%" PRIx64 "-%" PRIx64 " %s %" PRIx64 " %*x:%*x %*u %s\n", &start_addr, |
| &end_addr, type, &pgoff, execname) < 4) { |
| continue; |
| } |
| if (strcmp(execname, "") == 0) { |
| strcpy(execname, DEFAULT_EXECNAME_FOR_THREAD_MMAP); |
| } |
| ThreadMmap thread; |
| thread.start_addr = start_addr; |
| thread.len = end_addr - start_addr; |
| thread.pgoff = pgoff; |
| thread.name = execname; |
| thread.executable = (type[2] == 'x'); |
| thread_mmaps->push_back(thread); |
| } |
| return true; |
| } |
| |
| bool GetKernelBuildId(BuildId* build_id) { |
| ElfStatus result = GetBuildIdFromNoteFile("/sys/kernel/notes", build_id); |
| if (result != ElfStatus::NO_ERROR) { |
| LOG(DEBUG) << "failed to read /sys/kernel/notes: " << result; |
| } |
| return result == ElfStatus::NO_ERROR; |
| } |
| |
| bool GetModuleBuildId(const std::string& module_name, BuildId* build_id) { |
| std::string notefile = "/sys/module/" + module_name + "/notes/.note.gnu.build-id"; |
| return GetBuildIdFromNoteFile(notefile, build_id); |
| } |
| |
| bool GetValidThreadsFromThreadString(const std::string& tid_str, std::set<pid_t>* tid_set) { |
| std::vector<std::string> strs = android::base::Split(tid_str, ","); |
| for (const auto& s : strs) { |
| int tid; |
| if (!android::base::ParseInt(s.c_str(), &tid, 0)) { |
| LOG(ERROR) << "Invalid tid '" << s << "'"; |
| return false; |
| } |
| if (!IsDir(android::base::StringPrintf("/proc/%d", tid))) { |
| LOG(ERROR) << "Non existing thread '" << tid << "'"; |
| return false; |
| } |
| tid_set->insert(tid); |
| } |
| return true; |
| } |
| |
| /* |
| * perf event paranoia level: |
| * -1 - not paranoid at all |
| * 0 - disallow raw tracepoint access for unpriv |
| * 1 - disallow cpu events for unpriv |
| * 2 - disallow kernel profiling for unpriv |
| * 3 - disallow user profiling for unpriv |
| */ |
| static bool ReadPerfEventParanoid(int* value) { |
| std::string s; |
| if (!android::base::ReadFileToString("/proc/sys/kernel/perf_event_paranoid", &s)) { |
| PLOG(DEBUG) << "failed to read /proc/sys/kernel/perf_event_paranoid"; |
| return false; |
| } |
| s = android::base::Trim(s); |
| if (!android::base::ParseInt(s.c_str(), value)) { |
| PLOG(ERROR) << "failed to parse /proc/sys/kernel/perf_event_paranoid: " << s; |
| return false; |
| } |
| return true; |
| } |
| |
| static const char* GetLimitLevelDescription(int limit_level) { |
| switch (limit_level) { |
| case -1: return "unlimited"; |
| case 0: return "disallowing raw tracepoint access for unpriv"; |
| case 1: return "disallowing cpu events for unpriv"; |
| case 2: return "disallowing kernel profiling for unpriv"; |
| case 3: return "disallowing user profiling for unpriv"; |
| default: return "unknown level"; |
| } |
| } |
| |
| bool CheckPerfEventLimit() { |
| // root is not limited by /proc/sys/kernel/perf_event_paranoid. |
| if (IsRoot()) { |
| return true; |
| } |
| int limit_level; |
| bool can_read_paranoid = ReadPerfEventParanoid(&limit_level); |
| if (can_read_paranoid && limit_level <= 1) { |
| return true; |
| } |
| #if defined(__ANDROID__) |
| const char* prop_name = "security.perf_harden"; |
| char prop_value[PROP_VALUE_MAX]; |
| if (__system_property_get(prop_name, prop_value) <= 0) { |
| // can't do anything if there is no such property. |
| return true; |
| } |
| if (strcmp(prop_value, "0") == 0) { |
| return true; |
| } |
| // Try to enable perf_event_paranoid by setprop security.perf_harden=0. |
| if (__system_property_set(prop_name, "0") == 0) { |
| sleep(1); |
| if (can_read_paranoid && ReadPerfEventParanoid(&limit_level) && limit_level <= 1) { |
| return true; |
| } |
| if (__system_property_get(prop_name, prop_value) > 0 && strcmp(prop_value, "0") == 0) { |
| return true; |
| } |
| } |
| if (can_read_paranoid) { |
| LOG(WARNING) << "/proc/sys/kernel/perf_event_paranoid is " << limit_level |
| << ", " << GetLimitLevelDescription(limit_level) << "."; |
| } |
| LOG(WARNING) << "Try using `adb shell setprop security.perf_harden 0` to allow profiling."; |
| return false; |
| #else |
| if (can_read_paranoid) { |
| LOG(WARNING) << "/proc/sys/kernel/perf_event_paranoid is " << limit_level |
| << ", " << GetLimitLevelDescription(limit_level) << "."; |
| return false; |
| } |
| #endif |
| return true; |
| } |
| |
| bool CheckSampleFrequency(uint64_t sample_freq) { |
| if (sample_freq == 0) { |
| LOG(ERROR) << "Sample frequency can't be zero."; |
| return false; |
| } |
| std::string s; |
| if (!android::base::ReadFileToString("/proc/sys/kernel/perf_event_max_sample_rate", &s)) { |
| PLOG(DEBUG) << "failed to read /proc/sys/kernel/perf_event_max_sample_rate"; |
| // Omit the check if perf_event_max_sample_rate doesn't exist. |
| return true; |
| } |
| s = android::base::Trim(s); |
| uint64_t max_sample_freq; |
| if (!android::base::ParseUint(s.c_str(), &max_sample_freq)) { |
| LOG(ERROR) << "failed to parse /proc/sys/kernel/perf_event_max_sample_rate: " << s; |
| return false; |
| } |
| if (sample_freq > max_sample_freq) { |
| LOG(ERROR) << "Sample frequency " << sample_freq << " is out of range [1, " |
| << max_sample_freq << "]"; |
| return false; |
| } |
| return true; |
| } |
| |
| bool CheckKernelSymbolAddresses() { |
| const std::string kptr_restrict_file = "/proc/sys/kernel/kptr_restrict"; |
| std::string s; |
| if (!android::base::ReadFileToString(kptr_restrict_file, &s)) { |
| PLOG(DEBUG) << "failed to read " << kptr_restrict_file; |
| return false; |
| } |
| s = android::base::Trim(s); |
| int value; |
| if (!android::base::ParseInt(s.c_str(), &value)) { |
| LOG(ERROR) << "failed to parse " << kptr_restrict_file << ": " << s; |
| return false; |
| } |
| if (value == 0) { |
| return true; |
| } |
| if (value == 1 && IsRoot()) { |
| return true; |
| } |
| LOG(WARNING) << "Access to kernel symbol addresses is restricted. If " |
| << "possible, please do `echo 0 >/proc/sys/kernel/kptr_restrict` " |
| << "to fix this."; |
| return false; |
| } |
| |
| ArchType GetMachineArch() { |
| utsname uname_buf; |
| if (TEMP_FAILURE_RETRY(uname(&uname_buf)) != 0) { |
| PLOG(WARNING) << "uname() failed"; |
| return GetBuildArch(); |
| } |
| ArchType arch = GetArchType(uname_buf.machine); |
| if (arch != ARCH_UNSUPPORTED) { |
| return arch; |
| } |
| return GetBuildArch(); |
| } |