aarch64: Save/Restore PAC keys

Should fix #3568.

src/Task.cc

@@ -1278,7 +1278,50 @@ bool Task::get_aarch64_debug_regs(int which, ARM64Arch::user_hwdebug_state *regs
  fallible_ptrace(PTRACE_GETREGSET, which, (void*)&iov);
  return errno == 0;
 }
+std::vector<uint8_t> Task::pac_keys(bool *ok)
+{
+ std::vector<uint8_t> pac_data(
+ sizeof(ARM64Arch::user_pac_address_keys) +
+ sizeof(ARM64Arch::user_pac_generic_keys));
+ struct iovec vec = { pac_data.data(), sizeof(ARM64Arch::user_pac_address_keys) };
+ if (fallible_ptrace(PTRACE_GETREGSET, NT_ARM_PACA_KEYS, &vec)) {
+ if (ok) {
+ *ok = false;
+ }
+ return std::vector<uint8_t>{};
+ }
+ vec = { pac_data.data() + sizeof(ARM64Arch::user_pac_address_keys),
+ sizeof(ARM64Arch::user_pac_generic_keys) };
+ if (fallible_ptrace(PTRACE_GETREGSET, NT_ARM_PACG_KEYS, &vec)) {
+ if (ok) {
+ *ok = false;
+ }
+ return std::vector<uint8_t>{};
+ }
+ return pac_data;
+}
+bool Task::set_pac_keys(const std::vector<uint8_t> &pac_data)
+{
+ if (pac_data.empty()) {
+ return true;
+ }
+ struct iovec vec = { (void*)pac_data.data(), sizeof(ARM64Arch::user_pac_address_keys) };
+ if (fallible_ptrace(PTRACE_SETREGSET, NT_ARM_PACA_KEYS, &vec)) {
+ return false;
+ }
+ vec = { (void*)(pac_data.data() + sizeof(ARM64Arch::user_pac_address_keys)),
+ sizeof(ARM64Arch::user_pac_generic_keys) };
+ return !fallible_ptrace(PTRACE_SETREGSET, NT_ARM_PACG_KEYS, &vec);
+}
 #else
+std::vector<uint8_t> Task::pac_keys(bool *)
+{
+ return std::vector<uint8_t>{};
+}
+bool Task::set_pac_keys(const std::vector<uint8_t> &)
+{
+ return true;
+}
 bool Task::set_aarch64_debug_regs(int, ARM64Arch::user_hwdebug_state *, size_t) {
  FATAL() << "Reached aarch64 code path on non-aarch64 system";
  return false;

src/Task.h

@@ -528,6 +528,16 @@ class Task {
  */
  void set_x86_debug_status(uintptr_t status);
 
+ /**
+ * Read the (architecture-specific) pointer authentication keys of the current task
+ */
+ std::vector<uint8_t> pac_keys(bool *ok = nullptr);
+
+ /**
+ * Set the (architecture-specific) pointer authentication keys for the current task
+ */
+ bool set_pac_keys(const std::vector<uint8_t> &data);
+
  /**
  * Determine why a SIGTRAP occurred. On x86, uses x86_debug_status() but doesn't
  * consume it.

src/TraceStream.cc

@@ -778,6 +778,9 @@ void TraceWriter::write_task_event(const TraceTaskEvent& event) {
  exec.setExeBase(event.exe_base().as_int());
  exec.setInterpBase(event.interp_base().as_int());
  exec.setInterpName(str_to_data(event.interp_name()));;
+ auto pac_data = exec.initPacData();
+ std::vector<uint8_t> pac_data_vec = event.pac_data();
+ pac_data.setRaw(Data::Reader(pac_data_vec.data(), pac_data_vec.size()));
  break;
  }
  case TraceTaskEvent::EXIT:
@@ -840,6 +843,8 @@ TraceTaskEvent TraceReader::read_task_event(FrameTime* time) {
  r.exe_base_ = exec.getExeBase();
  r.interp_base_ = exec.getInterpBase();
  r.interp_name_ = data_to_str(exec.getInterpName());
+ auto pac_data = exec.getPacData().getRaw();
+ r.pac_data_ = std::vector<uint8_t>(pac_data.begin(), pac_data.end());
  break;
  }
  case trace::TaskEvent::Which::EXIT:

src/TraceTaskEvent.h

@@ -105,6 +105,14 @@ class TraceTaskEvent {
  DEBUG_ASSERT(type() == EXEC);
  interp_name_ = name;
  }
+ std::vector<uint8_t> pac_data() const {
+ DEBUG_ASSERT(type() == EXEC);
+ return pac_data_;
+ }
+ void set_pac_data(std::vector<uint8_t> data) {
+ DEBUG_ASSERT(type() == EXEC);
+ pac_data_ = data;
+ }
  WaitStatus exit_status() const {
  DEBUG_ASSERT(type() == EXIT);
  return exit_status_;
@@ -124,6 +132,7 @@ class TraceTaskEvent {
  remote_ptr<void> exe_base_; // EXEC only
  remote_ptr<void> interp_base_; // EXEC only
  std::string interp_name_; // EXEC only
+ std::vector<uint8_t> pac_data_; // EXEC only
  WaitStatus exit_status_; // EXIT only
 };
 

src/kernel_abi.h

@@ -2560,6 +2560,17 @@ struct ARM64Arch : public GenericArch<SupportedArch::aarch64, WordSize64Defs> {
  uint32_t rule_locs[0];
  };
  RR_VERIFY_TYPE_ARCH(SupportedArch::aarch64, struct ::ethtool_rxnfc, struct ethtool_rxnfc);
+
+ struct user_pac_address_keys {
+ __uint128_t apiakey;
+ __uint128_t apibkey;
+ __uint128_t apdakey;
+ __uint128_t apdbkey;
+ };
+
+ struct user_pac_generic_keys {
+ __uint128_t apgakey;
+ };
 };
 
 #define RR_ARCH_FUNCTION(f, arch, args...) \

src/record_syscall.cc

@@ -5772,6 +5772,7 @@ static void process_execve(RecordTask* t, TaskSyscallState& syscall_state) {
  }
  }
 
+ syscall_state.exec_saved_event->set_pac_data(t->pac_keys());
  t->session().trace_writer().write_task_event(*syscall_state.exec_saved_event);
 
  {

src/replay_syscall.cc

@@ -450,6 +450,9 @@ static void process_execve(ReplayTask* t, const TraceFrame& trace_frame,
  t->post_exec_syscall(exe_name, kms[exe_km].fsname());
  t->vm()->set_interp_base(tte.interp_base());
  t->vm()->set_interp_name(tte.interp_name());
+ if (!t->set_pac_keys(tte.pac_data())) {
+ LOG(warn) << "Failed to restore PAC keys. Replay may fail.";
+ }
 
  t->fd_table()->close_after_exec(
  t, t->current_trace_frame().event().Syscall().exec_fds_to_close);

src/rr_trace.capnp

@@ -218,6 +218,7 @@ struct TaskEvent {
  interpBase @10 :RemotePtr;
  # Not a Path since it is only meaningful during recording
  interpName @11 :CString;
+ pacData @12 :PACData;
  }
  # Most frame 'exit' events generate one of these, but these are not
  # generated if rr ends abnormally so the tasks did not in fact exit during
@@ -261,6 +262,11 @@ struct ExtraRegisters {
  raw @0 :Data;
 }
 
+struct PACData {
+ # Formay determined by Frame::arch
+ raw @0 :Data;
+}
+
 enum SyscallState {
  enteringPtrace @0;
  entering @1;