Reland protobuf tombstones.

This reverts the following commits:
    e156ede145a7fc671c705d045d89b49922a758b5.
    eda96eddcbdda9632166232b2363c7b84da0994d.
    5ec54d1e843729cd1e38a2f791f001226a653e95.
    1e45d3f2239333217d3252f78151f4294fda4e80.
    a50f61f8fa903117a6df82d164628de310f16ae9.

Test: treehugger
Test: atest -c CtsSeccompHostTestCases:android.seccomp.cts.SeccompHostJUnit4DeviceTest#testAppZygoteSyscalls
Change-Id: Ic2b1f489ac9f1fec7d7a33c845c29891f4306bbd

1 files changed, 478 insertions, 0 deletions

diff --git a/debuggerd/libdebuggerd/tombstone_proto.cpp b/debuggerd/libdebuggerd/tombstone_proto.cpp
new file mode 100644
index 000000000..801b11242
--- /dev/null
+++ b/debuggerd/libdebuggerd/tombstone_proto.cpp
@@ -0,0 +1,478 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#define LOG_TAG "DEBUG"
+
+#include "libdebuggerd/tombstone.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <time.h>
+
+#include <memory>
+#include <string>
+
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+
+#include <android/log.h>
+#include <log/log.h>
+#include <log/log_read.h>
+#include <log/logprint.h>
+#include <private/android_filesystem_config.h>
+
+#include <unwindstack/Maps.h>
+#include <unwindstack/Memory.h>
+#include <unwindstack/Regs.h>
+#include <unwindstack/Unwinder.h>
+
+#include "libdebuggerd/open_files_list.h"
+#include "libdebuggerd/utility.h"
+#include "util.h"
+
+#include "tombstone.pb.h"
+
+using android::base::StringPrintf;
+
+// Use the demangler from libc++.
+extern "C" char* __cxa_demangle(const char*, char*, size_t*, int* status);
+
+static Architecture get_arch() {
+#if defined(__arm__)
+  return Architecture::ARM32;
+#elif defined(__aarch64__)
+  return Architecture::ARM64;
+#elif defined(__i386__)
+  return Architecture::X86;
+#elif defined(__x86_64__)
+  return Architecture::X86_64;
+#else
+#error Unknown architecture!
+#endif
+}
+
+static std::optional<std::string> get_stack_overflow_cause(uint64_t fault_addr, uint64_t sp,
+                                                           unwindstack::Maps* maps) {
+  static constexpr uint64_t kMaxDifferenceBytes = 256;
+  uint64_t difference;
+  if (sp >= fault_addr) {
+    difference = sp - fault_addr;
+  } else {
+    difference = fault_addr - sp;
+  }
+  if (difference <= kMaxDifferenceBytes) {
+    // The faulting address is close to the current sp, check if the sp
+    // indicates a stack overflow.
+    // On arm, the sp does not get updated when the instruction faults.
+    // In this case, the sp will still be in a valid map, which is the
+    // last case below.
+    // On aarch64, the sp does get updated when the instruction faults.
+    // In this case, the sp will be in either an invalid map if triggered
+    // on the main thread, or in a guard map if in another thread, which
+    // will be the first case or second case from below.
+    unwindstack::MapInfo* map_info = maps->Find(sp);
+    if (map_info == nullptr) {
+      return "stack pointer is in a non-existent map; likely due to stack overflow.";
+    } else if ((map_info->flags & (PROT_READ | PROT_WRITE)) != (PROT_READ | PROT_WRITE)) {
+      return "stack pointer is not in a rw map; likely due to stack overflow.";
+    } else if ((sp - map_info->start) <= kMaxDifferenceBytes) {
+      return "stack pointer is close to top of stack; likely stack overflow.";
+    }
+  }
+  return {};
+}
+
+static void dump_probable_cause(Tombstone* tombstone, const siginfo_t* si, unwindstack::Maps* maps,
+                                unwindstack::Regs* regs) {
+  std::optional<std::string> cause;
+  if (si->si_signo == SIGSEGV && si->si_code == SEGV_MAPERR) {
+    if (si->si_addr < reinterpret_cast<void*>(4096)) {
+      cause = "null pointer dereference";
+    } else if (si->si_addr == reinterpret_cast<void*>(0xffff0ffc)) {
+      cause = "call to kuser_helper_version";
+    } else if (si->si_addr == reinterpret_cast<void*>(0xffff0fe0)) {
+      cause = "call to kuser_get_tls";
+    } else if (si->si_addr == reinterpret_cast<void*>(0xffff0fc0)) {
+      cause = "call to kuser_cmpxchg";
+    } else if (si->si_addr == reinterpret_cast<void*>(0xffff0fa0)) {
+      cause = "call to kuser_memory_barrier";
+    } else if (si->si_addr == reinterpret_cast<void*>(0xffff0f60)) {
+      cause = "call to kuser_cmpxchg64";
+    } else {
+      cause = get_stack_overflow_cause(reinterpret_cast<uint64_t>(si->si_addr), regs->sp(), maps);
+    }
+  } else if (si->si_signo == SIGSEGV && si->si_code == SEGV_ACCERR) {
+    uint64_t fault_addr = reinterpret_cast<uint64_t>(si->si_addr);
+    unwindstack::MapInfo* map_info = maps->Find(fault_addr);
+    if (map_info != nullptr && map_info->flags == PROT_EXEC) {
+      cause = "execute-only (no-read) memory access error; likely due to data in .text.";
+    } else {
+      cause = get_stack_overflow_cause(fault_addr, regs->sp(), maps);
+    }
+  } else if (si->si_signo == SIGSYS && si->si_code == SYS_SECCOMP) {
+    cause = StringPrintf("seccomp prevented call to disallowed %s system call %d", ABI_STRING,
+                         si->si_syscall);
+  }
+
+  if (cause) {
+    tombstone->mutable_cause()->set_human_readable(*cause);
+  }
+}
+
+static void dump_abort_message(Tombstone* tombstone, unwindstack::Unwinder* unwinder,
+                               const ProcessInfo& process_info) {
+  std::shared_ptr<unwindstack::Memory> process_memory = unwinder->GetProcessMemory();
+  uintptr_t address = process_info.abort_msg_address;
+  if (address == 0) {
+    return;
+  }
+
+  size_t length;
+  if (!process_memory->ReadFully(address, &length, sizeof(length))) {
+    PLOG(ERROR) << "Failed to read abort message header";
+    return;
+  }
+
+  // The length field includes the length of the length field itself.
+  if (length < sizeof(size_t)) {
+    LOG(ERROR) << "Abort message header malformed: claimed length = " << length;
+    return;
+  }
+
+  length -= sizeof(size_t);
+
+  // The abort message should be null terminated already, but reserve a spot for NUL just in case.
+  std::string msg;
+  msg.resize(length);
+
+  if (!process_memory->ReadFully(address + sizeof(length), &msg[0], length)) {
+    PLOG(ERROR) << "Failed to read abort message header";
+    return;
+  }
+
+  tombstone->set_abort_message(msg);
+}
+
+static void dump_open_fds(Tombstone* tombstone, const OpenFilesList* open_files) {
+  if (open_files) {
+    for (auto& [fd, entry] : *open_files) {
+      FD f;
+
+      f.set_fd(fd);
+
+      const std::optional<std::string>& path = entry.path;
+      if (path) {
+        f.set_path(*path);
+      }
+
+      const std::optional<uint64_t>& fdsan_owner = entry.fdsan_owner;
+      if (fdsan_owner) {
+        const char* type = android_fdsan_get_tag_type(*fdsan_owner);
+        uint64_t value = android_fdsan_get_tag_value(*fdsan_owner);
+        f.set_owner(type);
+        f.set_tag(value);
+      }
+
+      *tombstone->add_open_fds() = f;
+    }
+  }
+}
+
+static void dump_thread(Tombstone* tombstone, unwindstack::Unwinder* unwinder,
+                        const ThreadInfo& thread_info, bool memory_dump = false) {
+  Thread thread;
+
+  thread.set_id(thread_info.tid);
+  thread.set_name(thread_info.thread_name);
+
+  unwindstack::Maps* maps = unwinder->GetMaps();
+  unwindstack::Memory* memory = unwinder->GetProcessMemory().get();
+
+  thread_info.registers->IterateRegisters(
+      [&thread, memory_dump, maps, memory](const char* name, uint64_t value) {
+        Register r;
+        r.set_name(name);
+        r.set_u64(value);
+        *thread.add_registers() = r;
+
+        if (memory_dump) {
+          MemoryDump dump;
+
+          char buf[256];
+          size_t start_offset = 0;
+          ssize_t bytes = dump_memory(buf, sizeof(buf), &start_offset, &value, memory);
+          if (bytes == -1) {
+            return;
+          }
+
+          dump.set_register_name(name);
+
+          unwindstack::MapInfo* map_info = maps->Find(value);
+          if (map_info) {
+            dump.set_mapping_name(map_info->name);
+          }
+
+          dump.set_begin_address(value);
+
+          CHECK(start_offset + bytes <= sizeof(buf));
+          dump.set_memory(buf, start_offset + bytes);
+
+          *thread.add_memory_dump() = std::move(dump);
+        }
+      });
+
+  std::unique_ptr<unwindstack::Regs> regs_copy(thread_info.registers->Clone());
+  unwinder->SetRegs(regs_copy.get());
+  unwinder->Unwind();
+  if (unwinder->NumFrames() == 0) {
+    LOG(ERROR) << "Failed to unwind";
+    if (unwinder->LastErrorCode() != unwindstack::ERROR_NONE) {
+      LOG(ERROR) << "  Error code: " << unwinder->LastErrorCodeString();
+      LOG(ERROR) << "  Error address: " << StringPrintf("0x%" PRIx64, unwinder->LastErrorAddress());
+    }
+  } else {
+    unwinder->SetDisplayBuildID(true);
+    for (const auto& frame : unwinder->frames()) {
+      BacktraceFrame* f = thread.add_current_backtrace();
+      f->set_rel_pc(frame.rel_pc);
+      f->set_pc(frame.pc);
+      f->set_sp(frame.sp);
+
+      if (!frame.function_name.empty()) {
+        // TODO: Should this happen here, or on the display side?
+        char* demangled_name =
+            __cxa_demangle(frame.function_name.c_str(), nullptr, nullptr, nullptr);
+        if (demangled_name) {
+          f->set_function_name(demangled_name);
+          free(demangled_name);
+        } else {
+          f->set_function_name(frame.function_name);
+        }
+      }
+
+      f->set_function_offset(frame.function_offset);
+
+      if (frame.map_start == frame.map_end) {
+        // No valid map associated with this frame.
+        f->set_file_name("<unknown>");
+      } else if (!frame.map_name.empty()) {
+        f->set_file_name(frame.map_name);
+      } else {
+        f->set_file_name(StringPrintf("<anonymous:%" PRIx64 ">", frame.map_start));
+      }
+
+      f->set_file_map_offset(frame.map_elf_start_offset);
+
+      unwindstack::MapInfo* map_info = maps->Find(frame.map_start);
+      if (map_info) {
+        f->set_build_id(map_info->GetPrintableBuildID());
+      }
+    }
+  }
+
+  auto& threads = *tombstone->mutable_threads();
+  threads[thread_info.tid] = thread;
+}
+
+static void dump_main_thread(Tombstone* tombstone, unwindstack::Unwinder* unwinder,
+                             const ThreadInfo& thread_info) {
+  dump_thread(tombstone, unwinder, thread_info, true);
+}
+
+static void dump_mappings(Tombstone* tombstone, unwindstack::Unwinder* unwinder) {
+  unwindstack::Maps* maps = unwinder->GetMaps();
+  std::shared_ptr<unwindstack::Memory> process_memory = unwinder->GetProcessMemory();
+
+  for (const auto& map_info : *maps) {
+    auto* map = tombstone->add_memory_mappings();
+    map->set_begin_address(map_info->start);
+    map->set_end_address(map_info->end);
+    map->set_offset(map_info->offset);
+
+    if (map_info->flags & PROT_READ) {
+      map->set_read(true);
+    }
+    if (map_info->flags & PROT_WRITE) {
+      map->set_write(true);
+    }
+    if (map_info->flags & PROT_EXEC) {
+      map->set_execute(true);
+    }
+
+    map->set_mapping_name(map_info->name);
+
+    std::string build_id = map_info->GetPrintableBuildID();
+    if (!build_id.empty()) {
+      map->set_build_id(build_id);
+    }
+
+    map->set_load_bias(map_info->GetLoadBias(process_memory));
+  }
+}
+
+static void dump_log_file(Tombstone* tombstone, const char* logger, pid_t pid) {
+  logger_list* logger_list =
+      android_logger_list_open(android_name_to_log_id(logger), ANDROID_LOG_NONBLOCK, 0, pid);
+
+  LogBuffer buffer;
+
+  while (true) {
+    log_msg log_entry;
+    ssize_t actual = android_logger_list_read(logger_list, &log_entry);
+
+    if (actual < 0) {
+      if (actual == -EINTR) {
+        // interrupted by signal, retry
+        continue;
+      }
+      if (actual == -EAGAIN) {
+        // non-blocking EOF; we're done
+        break;
+      } else {
+        ALOGE("Error while reading log: %s\n", strerror(-actual));
+        break;
+      }
+    } else if (actual == 0) {
+      ALOGE("Got zero bytes while reading log: %s\n", strerror(errno));
+      break;
+    }
+
+    char timestamp_secs[32];
+    time_t sec = static_cast<time_t>(log_entry.entry.sec);
+    tm tm;
+    localtime_r(&sec, &tm);
+    strftime(timestamp_secs, sizeof(timestamp_secs), "%m-%d %H:%M:%S", &tm);
+    std::string timestamp =
+        StringPrintf("%s.%03d", timestamp_secs, log_entry.entry.nsec / 1'000'000);
+
+    // Msg format is: <priority:1><tag:N>\0<message:N>\0
+    char* msg = log_entry.msg();
+    if (msg == nullptr) {
+      continue;
+    }
+
+    unsigned char prio = msg[0];
+    char* tag = msg + 1;
+    msg = tag + strlen(tag) + 1;
+
+    // consume any trailing newlines
+    char* nl = msg + strlen(msg) - 1;
+    while (nl >= msg && *nl == '\n') {
+      *nl-- = '\0';
+    }
+
+    // Look for line breaks ('\n') and display each text line
+    // on a separate line, prefixed with the header, like logcat does.
+    do {
+      nl = strchr(msg, '\n');
+      if (nl != nullptr) {
+        *nl = '\0';
+        ++nl;
+      }
+
+      LogMessage* log_msg = buffer.add_logs();
+      log_msg->set_timestamp(timestamp);
+      log_msg->set_pid(log_entry.entry.pid);
+      log_msg->set_tid(log_entry.entry.tid);
+      log_msg->set_priority(prio);
+      log_msg->set_tag(tag);
+      log_msg->set_message(msg);
+    } while ((msg = nl));
+  }
+  android_logger_list_free(logger_list);
+
+  if (!buffer.logs().empty()) {
+    buffer.set_name(logger);
+    *tombstone->add_log_buffers() = std::move(buffer);
+  }
+}
+
+static void dump_logcat(Tombstone* tombstone, pid_t pid) {
+  dump_log_file(tombstone, "system", pid);
+  dump_log_file(tombstone, "main", pid);
+}
+
+void engrave_tombstone_proto(Tombstone* tombstone, unwindstack::Unwinder* unwinder,
+                             const std::map<pid_t, ThreadInfo>& threads, pid_t target_thread,
+                             const ProcessInfo& process_info, const OpenFilesList* open_files) {
+  Tombstone result;
+
+  result.set_arch(get_arch());
+  result.set_build_fingerprint(android::base::GetProperty("ro.build.fingerprint", "unknown"));
+  result.set_revision(android::base::GetProperty("ro.revision", "unknown"));
+  result.set_timestamp(get_timestamp());
+
+  const ThreadInfo& main_thread = threads.at(target_thread);
+  result.set_pid(main_thread.pid);
+  result.set_tid(main_thread.tid);
+  result.set_uid(main_thread.uid);
+  result.set_selinux_label(main_thread.selinux_label);
+
+  result.set_process_name(main_thread.process_name);
+  CHECK(main_thread.siginfo != nullptr);
+
+  Signal sig;
+  sig.set_number(main_thread.signo);
+  sig.set_name(get_signame(main_thread.siginfo));
+  sig.set_code(main_thread.siginfo->si_code);
+  sig.set_code_name(get_sigcode(main_thread.siginfo));
+
+  if (signal_has_sender(main_thread.siginfo, main_thread.pid)) {
+    sig.set_has_sender(true);
+    sig.set_sender_uid(main_thread.siginfo->si_uid);
+    sig.set_sender_pid(main_thread.siginfo->si_pid);
+  }
+
+  if (process_info.has_fault_address) {
+    sig.set_has_fault_address(true);
+    sig.set_fault_address(process_info.untagged_fault_address);
+  }
+
+  *result.mutable_signal_info() = sig;
+
+  dump_abort_message(&result, unwinder, process_info);
+
+  dump_main_thread(&result, unwinder, main_thread);
+
+  for (const auto& [tid, thread_info] : threads) {
+    if (tid != target_thread) {
+      dump_thread(&result, unwinder, thread_info);
+    }
+  }
+
+  dump_probable_cause(&result, main_thread.siginfo, unwinder->GetMaps(),
+                      main_thread.registers.get());
+
+  dump_mappings(&result, unwinder);
+
+  // Only dump logs on debuggable devices.
+  if (android::base::GetBoolProperty("ro.debuggable", false)) {
+    dump_logcat(&result, main_thread.pid);
+  }
+
+  dump_open_fds(&result, open_files);
+
+  *tombstone = std::move(result);
+}