commit 5a73e033054057381a358e68cf30b0ac3479fe07
author Evgenii Stepanov <eugenis@google.com> Wed Apr 29 14:59:44 2020 -0700
committer Evgenii Stepanov <eugenis@google.com> Fri May 01 14:06:54 2020 -0700
tree a1b50f3b0f76fe8b5bff1dcd0d3aadf5abd303c2
parent e75527347a3c68e7ecc976a67e30d08d28560c90

[libc] Zero and pattern initialization of heap memory.

Bug: 155227507
Test: scudo_unit_tests

Change-Id: I85075acfd85172f6cc7e48f79eeb577e293d0d30

libc/Android.bp

diff --git a/libc/Android.bp b/libc/Android.bp
index 4c36635..f366ddb 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -88,6 +88,12 @@
         experimental_mte: {
             cflags: ["-DANDROID_EXPERIMENTAL_MTE"],
         },
+        malloc_zero_contents: {
+            cflags: ["-DSCUDO_ZERO_CONTENTS"],
+        },
+        malloc_pattern_fill_contents: {
+            cflags: ["-DSCUDO_PATTERN_FILL_CONTENTS"],
+        },
     },
 }
 

libc/bionic/libc_init_common.cpp

diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index 12628f7..a47c2fc 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -52,6 +52,8 @@
 #include "pthread_internal.h"
 
 extern "C" int __system_properties_init(void);
+extern "C" void scudo_malloc_set_zero_contents(int);
+extern "C" void scudo_malloc_set_pattern_fill_contents(int);
 
 __LIBC_HIDDEN__ WriteProtected<libc_globals> __libc_globals;
 
@@ -83,6 +85,14 @@
   _thread_arc4_lock();
 }
 
+static void __libc_init_malloc_fill_contents() {
+#if defined(SCUDO_PATTERN_FILL_CONTENTS)
+  scudo_malloc_set_pattern_fill_contents(1);
+#elif defined(SCUDO_ZERO_CONTENTS)
+  scudo_malloc_set_zero_contents(1);
+#endif
+}
+
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
 void __libc_add_main_thread() {
   // Get the main thread from TLS and add it to the thread list.
@@ -106,6 +116,7 @@
   __libc_init_fdsan(); // Requires system properties (for debug.fdsan).
   __libc_init_fdtrack();
 
+  __libc_init_malloc_fill_contents();
   SetDefaultHeapTaggingLevel();
 }