| // Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "crash-reporter/user_collector.h" |
| |
| #include <grp.h> // For struct group. |
| #include <pcrecpp.h> |
| #include <pcrecpp.h> |
| #include <pwd.h> // For struct passwd. |
| #include <sys/types.h> // For getpwuid_r, getgrnam_r, WEXITSTATUS. |
| |
| #include <string> |
| #include <vector> |
| |
| #include "base/file_util.h" |
| #include "base/logging.h" |
| #include "base/string_util.h" |
| #include "chromeos/process.h" |
| #include "chromeos/syslog_logging.h" |
| #include "gflags/gflags.h" |
| |
| #pragma GCC diagnostic ignored "-Wstrict-aliasing" |
| DEFINE_bool(core2md_failure, false, "Core2md failure test"); |
| DEFINE_bool(directory_failure, false, "Spool directory failure test"); |
| DEFINE_string(filter_in, "", |
| "Ignore all crashes but this for testing"); |
| #pragma GCC diagnostic error "-Wstrict-aliasing" |
| |
| static const char kCollectionErrorSignature[] = |
| "crash_reporter-user-collection"; |
| // This procfs file is used to cause kernel core file writing to |
| // instead pipe the core file into a user space process. See |
| // core(5) man page. |
| static const char kCorePatternFile[] = "/proc/sys/kernel/core_pattern"; |
| static const char kCorePipeLimitFile[] = "/proc/sys/kernel/core_pipe_limit"; |
| // Set core_pipe_limit to 4 so that we can catch a few unrelated concurrent |
| // crashes, but finite to avoid infinitely recursing on crash handling. |
| static const char kCorePipeLimit[] = "4"; |
| static const char kCoreToMinidumpConverterPath[] = "/usr/bin/core2md"; |
| static const char kLeaveCoreFile[] = "/root/.leave_core"; |
| |
| static const char kDefaultLogConfig[] = "/etc/crash_reporter_logs.conf"; |
| |
| const char *UserCollector::kUserId = "Uid:\t"; |
| const char *UserCollector::kGroupId = "Gid:\t"; |
| |
| UserCollector::UserCollector() |
| : generate_diagnostics_(false), |
| core_pattern_file_(kCorePatternFile), |
| core_pipe_limit_file_(kCorePipeLimitFile), |
| initialized_(false) { |
| } |
| |
| void UserCollector::Initialize( |
| UserCollector::CountCrashFunction count_crash_function, |
| const std::string &our_path, |
| UserCollector::IsFeedbackAllowedFunction is_feedback_allowed_function, |
| bool generate_diagnostics) { |
| CrashCollector::Initialize(count_crash_function, |
| is_feedback_allowed_function); |
| our_path_ = our_path; |
| initialized_ = true; |
| generate_diagnostics_ = generate_diagnostics; |
| } |
| |
| UserCollector::~UserCollector() { |
| } |
| |
| std::string UserCollector::GetPattern(bool enabled) const { |
| if (enabled) { |
| // Combine the three crash attributes into one parameter to try to reduce |
| // the size of the invocation line for crash_reporter since the kernel |
| // has a fixed-sized (128B) buffer that it will truncate into. Note that |
| // the kernel does not support quoted arguments in core_pattern. |
| return StringPrintf("|%s --user=%%p:%%s:%%e", our_path_.c_str()); |
| } else { |
| return "core"; |
| } |
| } |
| |
| bool UserCollector::SetUpInternal(bool enabled) { |
| CHECK(initialized_); |
| LOG(INFO) << (enabled ? "Enabling" : "Disabling") << " user crash handling"; |
| |
| if (file_util::WriteFile(FilePath(core_pipe_limit_file_), |
| kCorePipeLimit, |
| strlen(kCorePipeLimit)) != |
| static_cast<int>(strlen(kCorePipeLimit))) { |
| LOG(ERROR) << "Unable to write " << core_pipe_limit_file_; |
| return false; |
| } |
| std::string pattern = GetPattern(enabled); |
| if (file_util::WriteFile(FilePath(core_pattern_file_), |
| pattern.c_str(), |
| pattern.length()) != |
| static_cast<int>(pattern.length())) { |
| LOG(ERROR) << "Unable to write " << core_pattern_file_; |
| return false; |
| } |
| return true; |
| } |
| |
| FilePath UserCollector::GetProcessPath(pid_t pid) { |
| return FilePath(StringPrintf("/proc/%d", pid)); |
| } |
| |
| bool UserCollector::GetSymlinkTarget(const FilePath &symlink, |
| FilePath *target) { |
| int max_size = 32; |
| scoped_array<char> buffer; |
| while (true) { |
| buffer.reset(new char[max_size + 1]); |
| ssize_t size = readlink(symlink.value().c_str(), buffer.get(), max_size); |
| if (size < 0) { |
| int saved_errno = errno; |
| LOG(ERROR) << "Readlink failed on " << symlink.value() << " with " |
| << saved_errno; |
| return false; |
| } |
| buffer[size] = 0; |
| if (size == max_size) { |
| // Avoid overflow when doubling. |
| if (max_size * 2 > max_size) { |
| max_size *= 2; |
| continue; |
| } else { |
| return false; |
| } |
| } |
| break; |
| } |
| |
| *target = FilePath(buffer.get()); |
| return true; |
| } |
| |
| bool UserCollector::GetExecutableBaseNameFromPid(uid_t pid, |
| std::string *base_name) { |
| FilePath target; |
| FilePath process_path = GetProcessPath(pid); |
| FilePath exe_path = process_path.Append("exe"); |
| if (!GetSymlinkTarget(exe_path, &target)) { |
| LOG(INFO) << "GetSymlinkTarget failed - Path " << process_path.value() |
| << " DirectoryExists: " |
| << file_util::DirectoryExists(process_path); |
| // Try to further diagnose exe readlink failure cause. |
| struct stat buf; |
| int stat_result = stat(exe_path.value().c_str(), &buf); |
| int saved_errno = errno; |
| if (stat_result < 0) { |
| LOG(INFO) << "stat " << exe_path.value() << " failed: " << stat_result |
| << " " << saved_errno; |
| } else { |
| LOG(INFO) << "stat " << exe_path.value() << " succeeded: st_mode=" |
| << buf.st_mode; |
| } |
| return false; |
| } |
| *base_name = target.BaseName().value(); |
| return true; |
| } |
| |
| bool UserCollector::GetIdFromStatus(const char *prefix, |
| IdKind kind, |
| const std::string &status_contents, |
| int *id) { |
| // From fs/proc/array.c:task_state(), this file contains: |
| // \nUid:\t<uid>\t<euid>\t<suid>\t<fsuid>\n |
| std::vector<std::string> status_lines; |
| SplitString(status_contents, '\n', &status_lines); |
| std::vector<std::string>::iterator line_iterator; |
| for (line_iterator = status_lines.begin(); |
| line_iterator != status_lines.end(); |
| ++line_iterator) { |
| if (line_iterator->find(prefix) == 0) |
| break; |
| } |
| if (line_iterator == status_lines.end()) { |
| return false; |
| } |
| std::string id_substring = line_iterator->substr(strlen(prefix), |
| std::string::npos); |
| std::vector<std::string> ids; |
| SplitString(id_substring, '\t', &ids); |
| if (ids.size() != kIdMax || kind < 0 || kind >= kIdMax) { |
| return false; |
| } |
| const char *number = ids[kind].c_str(); |
| char *end_number = NULL; |
| *id = strtol(number, &end_number, 10); |
| if (*end_number != '\0') |
| return false; |
| return true; |
| } |
| |
| void UserCollector::EnqueueCollectionErrorLog(pid_t pid, |
| const std::string &exec) { |
| FilePath crash_path; |
| LOG(INFO) << "Writing conversion problems as separate crash report."; |
| if (!GetCreatedCrashDirectoryByEuid(0, &crash_path, NULL)) { |
| LOG(ERROR) << "Could not even get log directory; out of space?"; |
| return; |
| } |
| std::string dump_basename = FormatDumpBasename(exec, time(NULL), pid); |
| std::string error_log = chromeos::GetLog(); |
| FilePath diag_log_path = GetCrashPath(crash_path, dump_basename, "diaglog"); |
| if (GetLogContents(FilePath(kDefaultLogConfig), kCollectionErrorSignature, |
| diag_log_path)) { |
| // We load the contents of diag_log into memory and append it to |
| // the error log. We cannot just append to files because we need |
| // to always create new files to prevent attack. |
| std::string diag_log_contents; |
| file_util::ReadFileToString(diag_log_path, &diag_log_contents); |
| error_log.append(diag_log_contents); |
| file_util::Delete(diag_log_path, false); |
| } |
| FilePath log_path = GetCrashPath(crash_path, dump_basename, "log"); |
| FilePath meta_path = GetCrashPath(crash_path, dump_basename, "meta"); |
| // We must use WriteNewFile instead of file_util::WriteFile as we do |
| // not want to write with root access to a symlink that an attacker |
| // might have created. |
| WriteNewFile(log_path, error_log.data(), error_log.length()); |
| AddCrashMetaData("sig", kCollectionErrorSignature); |
| WriteCrashMetaData(meta_path, exec, log_path.value()); |
| } |
| |
| bool UserCollector::CopyOffProcFiles(pid_t pid, |
| const FilePath &container_dir) { |
| if (!file_util::CreateDirectory(container_dir)) { |
| LOG(ERROR) << "Could not create " << container_dir.value().c_str(); |
| return false; |
| } |
| FilePath process_path = GetProcessPath(pid); |
| if (!file_util::PathExists(process_path)) { |
| LOG(ERROR) << "Path " << process_path.value() << " does not exist"; |
| return false; |
| } |
| static const char *proc_files[] = { |
| "auxv", |
| "cmdline", |
| "environ", |
| "maps", |
| "status" |
| }; |
| for (unsigned i = 0; i < arraysize(proc_files); ++i) { |
| if (!file_util::CopyFile(process_path.Append(proc_files[i]), |
| container_dir.Append(proc_files[i]))) { |
| LOG(ERROR) << "Could not copy " << proc_files[i] << " file"; |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool UserCollector::GetCreatedCrashDirectory(pid_t pid, |
| FilePath *crash_file_path, |
| bool *out_of_capacity) { |
| FilePath process_path = GetProcessPath(pid); |
| std::string status; |
| if (FLAGS_directory_failure) { |
| LOG(ERROR) << "Purposefully failing to create spool directory"; |
| return false; |
| } |
| if (!file_util::ReadFileToString(process_path.Append("status"), |
| &status)) { |
| LOG(ERROR) << "Could not read status file"; |
| LOG(INFO) << "Path " << process_path.value() << " DirectoryExists: " |
| << file_util::DirectoryExists(process_path); |
| return false; |
| } |
| int process_euid; |
| if (!GetIdFromStatus(kUserId, kIdEffective, status, &process_euid)) { |
| LOG(ERROR) << "Could not find euid in status file"; |
| return false; |
| } |
| if (!GetCreatedCrashDirectoryByEuid(process_euid, |
| crash_file_path, |
| out_of_capacity)) { |
| LOG(ERROR) << "Could not create crash directory"; |
| return false; |
| } |
| return true; |
| } |
| |
| bool UserCollector::CopyStdinToCoreFile(const FilePath &core_path) { |
| // Copy off all stdin to a core file. |
| FilePath stdin_path("/dev/fd/0"); |
| if (file_util::CopyFile(stdin_path, core_path)) { |
| return true; |
| } |
| |
| LOG(ERROR) << "Could not write core file"; |
| // If the file system was full, make sure we remove any remnants. |
| file_util::Delete(core_path, false); |
| return false; |
| } |
| |
| bool UserCollector::RunCoreToMinidump(const FilePath &core_path, |
| const FilePath &procfs_directory, |
| const FilePath &minidump_path, |
| const FilePath &temp_directory) { |
| FilePath output_path = temp_directory.Append("output"); |
| chromeos::ProcessImpl core2md; |
| core2md.RedirectOutput(output_path.value()); |
| core2md.AddArg(kCoreToMinidumpConverterPath); |
| core2md.AddArg(core_path.value()); |
| core2md.AddArg(procfs_directory.value()); |
| |
| if (!FLAGS_core2md_failure) { |
| core2md.AddArg(minidump_path.value()); |
| } else { |
| // To test how core2md errors are propagaged, cause an error |
| // by forgetting a required argument. |
| } |
| |
| int errorlevel = core2md.Run(); |
| |
| std::string output; |
| file_util::ReadFileToString(output_path, &output); |
| if (errorlevel != 0) { |
| LOG(ERROR) << "Problem during " << kCoreToMinidumpConverterPath |
| << " [result=" << errorlevel << "]: " << output; |
| return false; |
| } |
| |
| if (!file_util::PathExists(minidump_path)) { |
| LOG(ERROR) << "Minidump file " << minidump_path.value() |
| << " was not created"; |
| return false; |
| } |
| return true; |
| } |
| |
| bool UserCollector::ConvertCoreToMinidump(pid_t pid, |
| const FilePath &container_dir, |
| const FilePath &core_path, |
| const FilePath &minidump_path) { |
| if (!CopyOffProcFiles(pid, container_dir)) { |
| return false; |
| } |
| |
| if (!CopyStdinToCoreFile(core_path)) { |
| return false; |
| } |
| |
| bool conversion_result = RunCoreToMinidump( |
| core_path, |
| container_dir, // procfs directory |
| minidump_path, |
| container_dir); // temporary directory |
| |
| if (conversion_result) { |
| LOG(INFO) << "Stored minidump to " << minidump_path.value(); |
| } |
| |
| return conversion_result; |
| } |
| |
| bool UserCollector::ConvertAndEnqueueCrash(int pid, |
| const std::string &exec, |
| bool *out_of_capacity) { |
| FilePath crash_path; |
| if (!GetCreatedCrashDirectory(pid, &crash_path, out_of_capacity)) { |
| LOG(ERROR) << "Unable to find/create process-specific crash path"; |
| return false; |
| } |
| |
| // Directory like /tmp/crash_reporter.1234 which contains the |
| // procfs entries and other temporary files used during conversion. |
| FilePath container_dir = FilePath("/tmp").Append( |
| StringPrintf("crash_reporter.%d", pid)); |
| // Delete a pre-existing directory from crash reporter that may have |
| // been left around for diagnostics from a failed conversion attempt. |
| // If we don't, existing files can cause forking to fail. |
| file_util::Delete(container_dir, true); |
| std::string dump_basename = FormatDumpBasename(exec, time(NULL), pid); |
| FilePath core_path = GetCrashPath(crash_path, dump_basename, "core"); |
| FilePath meta_path = GetCrashPath(crash_path, dump_basename, "meta"); |
| FilePath minidump_path = GetCrashPath(crash_path, dump_basename, "dmp"); |
| FilePath log_path = GetCrashPath(crash_path, dump_basename, "log"); |
| |
| if (GetLogContents(FilePath(kDefaultLogConfig), exec, log_path)) |
| AddCrashMetaData("log", log_path.value()); |
| |
| if (!ConvertCoreToMinidump(pid, container_dir, core_path, |
| minidump_path)) { |
| LOG(INFO) << "Leaving core file at " << core_path.value() |
| << " due to conversion error"; |
| return false; |
| } |
| |
| // Here we commit to sending this file. We must not return false |
| // after this point or we will generate a log report as well as a |
| // crash report. |
| WriteCrashMetaData(meta_path, |
| exec, |
| minidump_path.value()); |
| |
| if (!file_util::PathExists(FilePath(kLeaveCoreFile))) { |
| file_util::Delete(core_path, false); |
| } else { |
| LOG(INFO) << "Leaving core file at " << core_path.value() |
| << " due to developer image"; |
| } |
| |
| file_util::Delete(container_dir, true); |
| return true; |
| } |
| |
| bool UserCollector::ParseCrashAttributes(const std::string &crash_attributes, |
| pid_t *pid, int *signal, |
| std::string *kernel_supplied_name) { |
| pcrecpp::RE re("(\\d+):(\\d+):(.*)"); |
| return re.FullMatch(crash_attributes, pid, signal, kernel_supplied_name); |
| } |
| |
| bool UserCollector::HandleCrash(const std::string &crash_attributes, |
| const char *force_exec) { |
| CHECK(initialized_); |
| int pid = 0; |
| int signal = 0; |
| std::string kernel_supplied_name; |
| |
| if (!ParseCrashAttributes(crash_attributes, &pid, &signal, |
| &kernel_supplied_name)) { |
| LOG(ERROR) << "Invalid parameter: --user=" << crash_attributes; |
| return false; |
| } |
| |
| std::string exec; |
| if (force_exec) { |
| exec.assign(force_exec); |
| } else if (!GetExecutableBaseNameFromPid(pid, &exec)) { |
| // If we cannot find the exec name, use the kernel supplied name. |
| // We don't always use the kernel's since it truncates the name to |
| // 16 characters. |
| exec = StringPrintf("supplied_%s", kernel_supplied_name.c_str()); |
| } |
| |
| // Allow us to test the crash reporting mechanism successfully even if |
| // other parts of the system crash. |
| if (!FLAGS_filter_in.empty() && |
| (FLAGS_filter_in == "none" || |
| FLAGS_filter_in != exec)) { |
| // We use a different format message to make it more obvious in tests |
| // which crashes are test generated and which are real. |
| LOG(WARNING) << "Ignoring crash from " << exec << "[" << pid << "] while " |
| << "filter_in=" << FLAGS_filter_in << "."; |
| return true; |
| } |
| |
| bool feedback = is_feedback_allowed_function_(); |
| const char *handling_string = "handling"; |
| if (!feedback) { |
| handling_string = "ignoring - no consent"; |
| } |
| |
| // Treat Chrome crashes as if the user opted-out. We stop counting Chrome |
| // crashes towards user crashes, so user crashes really mean non-Chrome |
| // user-space crashes. |
| if (exec == "chrome" || exec == "supplied_chrome") { |
| feedback = false; |
| handling_string = "ignoring - chrome crash"; |
| } |
| |
| LOG(WARNING) << "Received crash notification for " << exec << "[" << pid |
| << "] sig " << signal << " (" << handling_string << ")"; |
| |
| if (feedback) { |
| count_crash_function_(); |
| |
| if (generate_diagnostics_) { |
| bool out_of_capacity = false; |
| bool convert_and_enqueue_result = |
| ConvertAndEnqueueCrash(pid, exec, &out_of_capacity); |
| if (!convert_and_enqueue_result) { |
| if (!out_of_capacity) |
| EnqueueCollectionErrorLog(pid, exec); |
| return false; |
| } |
| } |
| } |
| |
| return true; |
| } |