debuggerd_handler: raise ambient capset before execing.
Raise the ambient capability set to match CapEff so that crash_dump can
inherit all of the capabilities of the dumped process to be able to
ptrace. Note that selinux will prevent crash_dump from actually use
any of the capabilities.
Bug: http://b/34853272
Test: debuggerd -b `pidof system_server`
Test: debuggerd -b `pidof zygote`
Change-Id: I1fe69eff54c1c0a5b3ec63f6fa504b2681c47a88
diff --git a/debuggerd/handler/debuggerd_handler.cpp b/debuggerd/handler/debuggerd_handler.cpp
index cd491d6..4cc077d 100644
--- a/debuggerd/handler/debuggerd_handler.cpp
+++ b/debuggerd/handler/debuggerd_handler.cpp
@@ -39,6 +39,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/capability.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/socket.h>
@@ -205,6 +206,11 @@
close(pipefds[0]);
close(pipefds[1]);
+ // Set all of the ambient capability bits we can, so that crash_dump can ptrace us.
+ for (unsigned long i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0); ++i) {
+ prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, i, 0, 0);
+ }
+
char buf[10];
snprintf(buf, sizeof(buf), "%d", thread_info->crashing_tid);
execl(CRASH_DUMP_PATH, CRASH_DUMP_NAME, buf, nullptr);