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    Subject[PATCH 5.13 749/800] selftests/sgx: remove checks for file execute permissions
    Date
    From: Dave Hansen <dave.hansen@linux.intel.com>

    [ Upstream commit 4896df9d53ae5521f3ce83751e828ad70bc65c80 ]

    The SGX selftests can fail for a bunch of non-obvious reasons
    like 'noexec' permissions on /dev (which is the default *EVERYWHERE*
    it seems).

    A new test mistakenly also looked for +x permission on the
    /dev/sgx_enclave. File execute permissions really only apply to
    the ability of execve() to work on a file, *NOT* on the ability
    for an application to map the file with PROT_EXEC. SGX needs to
    mmap(PROT_EXEC), but doesn't need to execve() the device file.

    Remove the check.

    Fixes: 4284f7acb78b ("selftests/sgx: Improve error detection and messages")
    Reported-by: Tim Gardner <tim.gardner@canonical.com>
    Cc: Jarkko Sakkinen <jarkko@kernel.org>
    Cc: Reinette Chatre <reinette.chatre@intel.com>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Shuah Khan <shuah@kernel.org>
    Cc: linux-sgx@vger.kernel.org
    Cc: linux-kselftest@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Tested-by: Reinette Chatre <reinette.chatre@intel.com>
    Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
    Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
    Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/testing/selftests/sgx/load.c | 16 +++-------------
    1 file changed, 3 insertions(+), 13 deletions(-)

    diff --git a/tools/testing/selftests/sgx/load.c b/tools/testing/selftests/sgx/load.c
    index f441ac34b4d4..bae78c3263d9 100644
    --- a/tools/testing/selftests/sgx/load.c
    +++ b/tools/testing/selftests/sgx/load.c
    @@ -150,16 +150,6 @@ bool encl_load(const char *path, struct encl *encl)
    goto err;
    }

    - /*
    - * This just checks if the /dev file has these permission
    - * bits set. It does not check that the current user is
    - * the owner or in the owning group.
    - */
    - if (!(sb.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))) {
    - fprintf(stderr, "no execute permissions on device file %s\n", device_path);
    - goto err;
    - }
    -
    ptr = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
    if (ptr == (void *)-1) {
    perror("mmap for read");
    @@ -169,13 +159,13 @@ bool encl_load(const char *path, struct encl *encl)

    #define ERR_MSG \
    "mmap() succeeded for PROT_READ, but failed for PROT_EXEC.\n" \
    -" Check that current user has execute permissions on %s and \n" \
    -" that /dev does not have noexec set: mount | grep \"/dev .*noexec\"\n" \
    +" Check that /dev does not have noexec set:\n" \
    +" \tmount | grep \"/dev .*noexec\"\n" \
    " If so, remount it executable: mount -o remount,exec /dev\n\n"

    ptr = mmap(NULL, PAGE_SIZE, PROT_EXEC, MAP_SHARED, fd, 0);
    if (ptr == (void *)-1) {
    - fprintf(stderr, ERR_MSG, device_path);
    + fprintf(stderr, ERR_MSG);
    goto err;
    }
    munmap(ptr, PAGE_SIZE);
    --
    2.30.2


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