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Commit 6585b0f0 authored by Kalesh Singh's avatar Kalesh Singh Committed by Automerger Merge Worker
Browse files

Merge "x86_64: mmap rnd bits: Allow min bits of less than 32" into main am: 72d88821 

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2825759



Change-Id: I9672c7ca311a3af7b860b49218697e4239b2740c
Signed-off-by: default avatarAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
parents cd6c434d 72d88821

init/security.cpp

+7 −2
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <errno.h>

#include <fcntl.h>

#include <linux/perf_event.h>

#include <math.h>

#include <selinux/selinux.h>

#include <sys/ioctl.h>

#include <sys/syscall.h>
@@ -121,8 +122,12 @@ Result<void> SetMmapRndBitsAction(const BuiltinArguments&) { 
    }

#elif defined(__x86_64__)

    // x86_64 supports 28 - 32 rnd bits, but Android wants to ensure that the

    // theoretical maximum of 32 bits is always supported and used.

    if (SetMmapRndBitsMin(32, 32, false) && (!Has32BitAbi() || SetMmapRndBitsMin(16, 16, true))) {

    // theoretical maximum of 32 bits is always supported and used; except in

    // the case of the x86 page size emulator which supports a maximum

    // of 30 bits for 16k page size, or 28 bits for 64k page size.

    int max_bits = 32 - (static_cast<int>(log2(getpagesize())) - 12);

    if (SetMmapRndBitsMin(max_bits, max_bits, false) &&

        (!Has32BitAbi() || SetMmapRndBitsMin(16, 16, true))) {

        return {};

    }

#elif defined(__arm__) || defined(__i386__)