Re: [Qemu-devel] [PATCH v2 for 3.0 1/2] linux-user/mmap.c: handle invalid len maps correctly

[Laurent Vivier]

Le 30/07/2018 à 15:43, Alex Bennée a écrit :
> I've slightly re-organised the check to more closely match the
> sequence that the kernel uses in do_mmap(). We check for both the zero
> case (EINVAL) and the overflow length case (ENOMEM).
> 
> Signed-off-by: Alex Bennée <address@hidden>
> Cc: umarcor <address@hidden>
> 
> ---
> v2
>   - add comment on overflow
> ---
>  linux-user/mmap.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index d0c50e4888..41e0983ce8 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -391,14 +391,23 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, 
> int prot,
>      }
>  #endif
>  
> -    if (offset & ~TARGET_PAGE_MASK) {
> +    if (!len) {
>          errno = EINVAL;
>          goto fail;
>      }
>  
> +    /* Also check for overflows... */
>      len = TARGET_PAGE_ALIGN(len);
> -    if (len == 0)
> -        goto the_end;
> +    if (!len) {
> +        errno = ENOMEM;
> +        goto fail;
> +    }
> +
> +    if (offset & ~TARGET_PAGE_MASK) {
> +        errno = EINVAL;
> +        goto fail;
> +    }
> +
>      real_start = start & qemu_host_page_mask;
>      host_offset = offset & qemu_host_page_mask;
>  
> 

Reviewed-by: Laurent Vivier <address@hidden>