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Commit cf140fb7 authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Check get_gwp_asan_callbacks before calling. 

When using the bootstrap linker, the get_gwp_asan_callbacks is
not set. Therefore, check it is not nullptr before calling it
during crash processing.

Bug: 284098779

Test: Ran crasher64 using /system/bin/bootstrap/linker64 and verify
Test: debuggerd code does not crash.
Test: All unit tests pass.
Change-Id: Ifc710fe4bef24661700444a1b69432bfc29d580f
Merged-In: Ifc710fe4bef24661700444a1b69432bfc29d580f
(cherry picked from commit 004a1673)
parent 7003fba5

debuggerd/handler/debuggerd_handler.cpp

+18 −14
Original line number Diff line number Diff line
@@ -566,13 +566,15 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c 
    process_info = g_callbacks.get_process_info();

  }



  gwp_asan_callbacks_t gwp_asan_callbacks = {};

  if (g_callbacks.get_gwp_asan_callbacks != nullptr) {

    // GWP-ASan catches use-after-free and heap-buffer-overflow by using PROT_NONE

    // guard pages, which lead to SEGV. Normally, debuggerd prints a bug report

    // and the process terminates, but in some cases, we actually want to print

    // the bug report and let the signal handler return, and restart the process.

    // In order to do that, we need to disable GWP-ASan's guard pages. The

    // following callbacks handle this case.

  gwp_asan_callbacks_t gwp_asan_callbacks = g_callbacks.get_gwp_asan_callbacks();

    gwp_asan_callbacks = g_callbacks.get_gwp_asan_callbacks();

    if (signal_number == SIGSEGV && signal_has_si_addr(info) &&

        gwp_asan_callbacks.debuggerd_needs_gwp_asan_recovery &&

        gwp_asan_callbacks.debuggerd_gwp_asan_pre_crash_report &&
@@ -581,6 +583,7 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c 
      gwp_asan_callbacks.debuggerd_gwp_asan_pre_crash_report(info->si_addr);

      process_info.recoverable_gwp_asan_crash = true;

    }

  }



  // If sival_int is ~0, it means that the fallback handler has been called

  // once before and this function is being called again to dump the stack
@@ -764,6 +767,7 @@ void debuggerd_init(debuggerd_callbacks_t* callbacks) { 
bool debuggerd_handle_signal(int signal_number, siginfo_t* info, void* context) {

  if (signal_number != SIGSEGV || !signal_has_si_addr(info)) return false;



  if (g_callbacks.get_gwp_asan_callbacks == nullptr) return false;

  gwp_asan_callbacks_t gwp_asan_callbacks = g_callbacks.get_gwp_asan_callbacks();

  if (gwp_asan_callbacks.debuggerd_needs_gwp_asan_recovery == nullptr ||

      gwp_asan_callbacks.debuggerd_gwp_asan_pre_crash_report == nullptr ||