P PPR1.180114.001 merge 3926655cda1c63b97fd35c7d6f337504c1ec2741 - clean

Change-Id: I72d227485017ef4a6003997524628c4c78be521d

1 files changed, 17 insertions, 1 deletions

diff --git a/debuggerd/handler/debuggerd_handler.cpp b/debuggerd/handler/debuggerd_handler.cpp
index 5d9cffb38..5a94d3dcf 100644
--- a/debuggerd/handler/debuggerd_handler.cpp
+++ b/debuggerd/handler/debuggerd_handler.cpp
@@ -498,7 +498,18 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c
   if (prctl(PR_SET_DUMPABLE, 1) != 0) {
      fatal_errno("failed to set dumpable");
   }
-           
+
+  // On kernels with yama_ptrace enabled, also allow any process to attach.
+  bool restore_orig_ptracer = true;
+  if (prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY) != 0) {
+    if (errno == EINVAL) {
+      // This kernel does not support PR_SET_PTRACER_ANY, or Yama is not enabled.
+      restore_orig_ptracer = false;
+    } else {
+      fatal_errno("failed to set traceable");
+    }
+  }
+
   // Essentially pthread_create without CLONE_FILES, so we still work during file descriptor
   // exhaustion.
   pid_t child_pid =
@@ -525,6 +536,11 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c
     signal(signal_number, SIG_DFL);
   }
 
+  // Restore PR_SET_PTRACER to its original value.
+  if (restore_orig_ptracer && prctl(PR_SET_PTRACER, 0) != 0) {
+    fatal_errno("failed to restore traceable");
+  }
+
   if (info->si_signo == DEBUGGER_SIGNAL) {
     // If the signal is fatal, don't unlock the mutex to prevent other crashing threads from
     // starting to dump right before our death.