Re: [Qemu-devel] [PATCH] linux-user: Check array bounds in errno conversion

[Laurent Vivier]

Le 03/03/2016 19:35, Peter Maydell a écrit :
> From: Timothy E Baldwin <address@hidden>
> 
> Check array bounds in host_to_target_errno() and target_to_host_errno().
> 
> Signed-off-by: Timothy Edward Baldwin <address@hidden>
> Message-id: address@hidden
> [PMM: Add a lower-bound check, use braces on if(), tweak commit message]
> Signed-off-by: Peter Maydell <address@hidden>

Reviewed-by: Laurent Vivier <address@hidden>

> ---
> This is a bugfix patch fished out of Timothy's signal-race-fixes
> patch series. We had a previous go-around doing this with unsigned
> integers, but that doesn't work.
> 
>  linux-user/syscall.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 9517531..f9dcdd4 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -617,15 +617,19 @@ static uint16_t 
> host_to_target_errno_table[ERRNO_TABLE_SIZE] = {
>  
>  static inline int host_to_target_errno(int err)
>  {
> -    if(host_to_target_errno_table[err])
> +    if (err >= 0 && err < ERRNO_TABLE_SIZE &&
> +        host_to_target_errno_table[err]) {
>          return host_to_target_errno_table[err];
> +    }
>      return err;
>  }
>  
>  static inline int target_to_host_errno(int err)
>  {
> -    if (target_to_host_errno_table[err])
> +    if (err >= 0 && err < ERRNO_TABLE_SIZE &&
> +        target_to_host_errno_table[err]) {
>          return target_to_host_errno_table[err];
> +    }
>      return err;
>  }
>  
>