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Commit 790ef057 authored by Elliott Hughes's avatar Elliott Hughes
Browse files

ashmem: ensure ashmem fds are CLOEXEC. 

Fix the memfd_create(2) path and add the missing unit test.

Bug: https://issuetracker.google.com/165667331
Test: treehugger
Change-Id: Ibb5c1d0f9d7caba1df04d1f03e82e55026d9f86a
parent 6233b239

libcutils/ashmem-dev.cpp

+7 −3
Original line number Diff line number Diff line
@@ -159,9 +159,11 @@ static bool __has_memfd_support() { 
        return false;

    }



    /* Check if kernel support exists, otherwise fall back to ashmem */

    // 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.

    android::base::unique_fd fd(

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

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

    if (fd == -1) {

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

        return false;
@@ -333,7 +335,9 @@ int ashmem_valid(int fd) 
}



static int memfd_create_region(const char* name, size_t size) {

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

    // 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));



    if (fd == -1) {

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

libcutils/ashmem_test.cpp

+5 −0
Original line number Diff line number Diff line
@@ -35,6 +35,11 @@ void TestCreateRegion(size_t size, unique_fd &fd, int prot) { 
    ASSERT_TRUE(ashmem_valid(fd));

    ASSERT_EQ(size, static_cast<size_t>(ashmem_get_size_region(fd)));

    ASSERT_EQ(0, ashmem_set_prot_region(fd, prot));



    // We've been inconsistent historically about whether or not these file

    // descriptors were CLOEXEC. Make sure we're consistent going forward.

    // https://issuetracker.google.com/165667331

    ASSERT_EQ(FD_CLOEXEC, (fcntl(fd, F_GETFD) & FD_CLOEXEC));

}



void TestMmap(const unique_fd& fd, size_t size, int prot, void** region, off_t off = 0) {