On 24 November 2016 at 16:08, Lena Djokic <lena.djo...@rt-rk.com> wrote:
> If fourth argument is NULL it should be passed without
> using lock_user function which would, in that case, return
> EFAULT, and system call supports passing NULL as fourth argument.
>
> Signed-off-by: Lena Djokic <lena.djo...@rt-rk.com>
> ---
> linux-user/syscall.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 3faf4f0..dad03e9 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -11694,17 +11694,22 @@ abi_long do_syscall(void *cpu_env, int num,
> abi_long arg1,
> case TARGET_NR_mq_open:
> {
> struct mq_attr posix_mq_attr;
> + struct mq_attr *pposix_mq_attr;
> int host_flags;
>
> host_flags = target_to_host_bitmask(arg2, fcntl_flags_tbl);
> - if (copy_from_user_mq_attr(&posix_mq_attr, arg4) != 0) {
> - goto efault;
> + pposix_mq_attr = NULL;
> + if (arg4) {
> + if (copy_from_user_mq_attr(&posix_mq_attr, arg4) != 0) {
> + goto efault;
> + }
> + pposix_mq_attr = &posix_mq_attr;
> }
> p = lock_user_string(arg1 - 1);
> if (!p) {
> goto efault;
> }
> - ret = get_errno(mq_open(p, host_flags, arg3, &posix_mq_attr));
> + ret = get_errno(mq_open(p, host_flags, arg3, pposix_mq_attr));
> unlock_user (p, arg1, 0);
> }
> break;
> --
> 2.7.4
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
thanks
-- PMM
