Re: [PATCH] linux-user: Fix 'utimensat()' implementation

[Laurent Vivier]

Le 11/08/2020 à 13:31, Filip Bozuta a écrit :
> Implementation of syscall 'utimensat()' in 'syscall.c' uses functions
> target_to_host/host_to_target_timespec() to convert values of
> 'struct timespec' between host and target. However, the implementation
> doesn't check whether the conversion succeeds and thus can cause an
> inappropriate error or succeed unappropriately instead of setting errno
> EFAULT ('Bad address') which is supposed to be set in these cases.
> 
> This was confirmed with the LTP test for utimensat ('testcases/utimensat')
> which fails for test cases when the errno EFAULT is expected. After changes
> from this patch, the test passes for all test cases.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/syscall.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 05f03919ff..920656191b 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -11722,8 +11722,13 @@ static abi_long do_syscall1(void *cpu_env, int num, 
> abi_long arg1,
>              if (!arg3) {
>                  tsp = NULL;
>              } else {
> -                target_to_host_timespec(ts, arg3);
> -                target_to_host_timespec(ts+1, arg3+sizeof(struct 
> target_timespec));
> +                if (target_to_host_timespec(ts, arg3)) {
> +                    return -TARGET_EFAULT;
> +                }
> +                if (target_to_host_timespec(ts + 1, arg3 +
> +                                            sizeof(struct target_timespec))) 
> {
> +                    return -TARGET_EFAULT;
> +                }
>                  tsp = ts;
>              }
>              if (!arg2)
> 

Applied to my linux-user-for-5.2 branch.

Thanks,
Laurent