From d3d8abeb1499d51fc2d881d933e4059fbffe448c Mon Sep 17 00:00:00 2001
From: Jared Duke <jdduke@google.com>
Date: Fri, 27 Aug 2021 10:20:04 -0700
Subject: [PATCH] Remove unnecessary ASLR workaround

The ADDR_NO_RANDOMIZE workaround for ASLR is not required for 3.4+
kernels. As Android 11+ requires kernel 4.4+, this workaround can be
safely removed from app startup.

Bug: 193448904
Test: Manual
Change-Id: I3c5517c34176573256176a4753f4a9113a62a49f
---
 core/jni/com_android_internal_os_Zygote.cpp | 30 ---------------------
 1 file changed, 30 deletions(-)

diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index 8b9a688a63e79..515c08d8517e2 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -62,7 +62,6 @@
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/un.h>
-#include <sys/utsname.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
@@ -837,26 +836,6 @@ static void MountEmulatedStorage(uid_t uid, jint mount_mode,
   }
 }
 
-static bool NeedsNoRandomizeWorkaround() {
-#if !defined(__arm__)
-    return false;
-#else
-    int major;
-    int minor;
-    struct utsname uts;
-    if (uname(&uts) == -1) {
-        return false;
-    }
-
-    if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) {
-        return false;
-    }
-
-    // Kernels before 3.4.* need the workaround.
-    return (major < 3) || ((major == 3) && (minor < 4));
-#endif
-}
-
 // Utility to close down the Zygote socket file descriptors while
 // the child is still running as root with Zygote's privileges.  Each
 // descriptor (if any) is closed via dup3(), replacing it with a valid
@@ -1687,15 +1666,6 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
     // runtime.
     runtime_flags &= ~RuntimeFlags::GWP_ASAN_LEVEL_MASK;
 
-    if (NeedsNoRandomizeWorkaround()) {
-        // Work around ARM kernel ASLR lossage (http://b/5817320).
-        int old_personality = personality(0xffffffff);
-        int new_personality = personality(old_personality | ADDR_NO_RANDOMIZE);
-        if (new_personality == -1) {
-            ALOGW("personality(%d) failed: %s", new_personality, strerror(errno));
-        }
-    }
-
     SetCapabilities(permitted_capabilities, effective_capabilities, permitted_capabilities,
                     fail_fn);