Only initialize the global stack protector once.
Before, dynamic executables would initialize the global stack protector
twice, once for the linker, and once for the executable. This worked
because the result was the same for both initializations, because it
used getauxval(AT_RANDOM), which won't be the case once arc4random gets
used for it.
Bug: http://b/29622562
Change-Id: I7718b1ba8ee8fac7127ab2360cb1088e510fef5c
Test: ran the stack protector tests on angler (32/64bit, static/dynamic)
diff --git a/libc/bionic/libc_init_dynamic.cpp b/libc/bionic/libc_init_dynamic.cpp
index ab48fb8..43bca30 100644
--- a/libc/bionic/libc_init_dynamic.cpp
+++ b/libc/bionic/libc_init_dynamic.cpp
@@ -52,6 +52,7 @@
#include "libc_init_common.h"
#include "private/bionic_globals.h"
+#include "private/bionic_ssp.h"
#include "private/bionic_tls.h"
#include "private/KernelArgumentBlock.h"
@@ -74,6 +75,10 @@
// __libc_init_common() will change the TLS area so the old one won't be accessible anyway.
*args_slot = NULL;
+ // The linker has initialized its copy of the global stack_chk_guard, and filled in the main
+ // thread's TLS slot with that value. Initialize the local global stack guard with its value.
+ __stack_chk_guard = reinterpret_cast<uintptr_t>(tls[TLS_SLOT_STACK_GUARD]);
+
__libc_init_globals(*args);
__libc_init_common(*args);