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Commit 056fd98b authored by Isaac Manjarres's avatar Isaac Manjarres Committed by Automerger Merge Worker
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Merge "ashmem: Ensure all memfds have non-executable permissions by default"... 

Merge "ashmem: Ensure all memfds have non-executable permissions by default" into main am: 445d2e00 am: 54fcd052

Original change: https://android-review.googlesource.com/c/platform/system/core/+/3388580



Change-Id: I23159135ac258a71074d3d6e66ae58c95f0d190a
Signed-off-by: default avatarAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
parents fd1e8b2f 54fcd052

libcutils/ashmem-dev.cpp

+14 −2
Original line number Diff line number Diff line
@@ -114,8 +114,14 @@ static bool __has_memfd_support() { 
    // Check if kernel support exists, otherwise fall back to ashmem.

    // This code needs to build on old API levels, so we can't use the libc

    // wrapper.

    //

    // MFD_NOEXEC_SEAL is used to match the semantics of the ashmem device,

    // which did not have executable permissions. This also seals the executable

    // permissions of the buffer (i.e. they cannot be changed by fchmod()).

    //

    // MFD_NOEXEC_SEAL implies MFD_ALLOW_SEALING.

    android::base::unique_fd fd(

            syscall(__NR_memfd_create, "test_android_memfd", MFD_CLOEXEC | MFD_ALLOW_SEALING));

            syscall(__NR_memfd_create, "test_android_memfd", MFD_CLOEXEC | MFD_NOEXEC_SEAL));

    if (fd == -1) {

        ALOGE("memfd_create failed: %s, no memfd support.\n", strerror(errno));

        return false;
@@ -289,7 +295,13 @@ int ashmem_valid(int fd) 
static int memfd_create_region(const char* name, size_t size) {

    // This code needs to build on old API levels, so we can't use the libc

    // wrapper.

    android::base::unique_fd fd(syscall(__NR_memfd_create, name, MFD_CLOEXEC | MFD_ALLOW_SEALING));

    //

    // MFD_NOEXEC_SEAL to match the semantics of the ashmem device, which did

    // not have executable permissions. This also seals the executable

    // permissions of the buffer (i.e. they cannot be changed by fchmod()).

    //

    // MFD_NOEXEC_SEAL implies MFD_ALLOW_SEALING.

    android::base::unique_fd fd(syscall(__NR_memfd_create, name, MFD_CLOEXEC | MFD_NOEXEC_SEAL));



    if (fd == -1) {

        ALOGE("memfd_create(%s, %zd) failed: %s\n", name, size, strerror(errno));