[U-Boot] [RFC PATCH 3/8] lib: net_utils: make string_to_ip stricter

[Chris Packham]

On Mon, Oct 12, 2015 at 8:43 PM, Chris Packham <judge.packham at gmail.com> wrote:
> Previously values greater than 255 were implicitly truncated. Add some
> stricter checking to reject addresses with components >255.
>
> With the input "1234192.168.1.1" the old behaviour would truncate the
> address to 192.168.1.1. New behaviour rejects the string outright and
> returns 0.0.0.0, which for the purposes of IP addresses can be
> considered an error.
>
> Signed-off-by: Chris Packham <judge.packham at gmail.com>
> ---
>
>  lib/net_utils.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/lib/net_utils.c b/lib/net_utils.c
> index cfae842..0fca54d 100644
> --- a/lib/net_utils.c
> +++ b/lib/net_utils.c
> @@ -24,10 +24,19 @@ struct in_addr string_to_ip(const char *s)
>
>         for (addr.s_addr = 0, i = 0; i < 4; ++i) {
>                 ulong val = s ? simple_strtoul(s, &e, 10) : 0;
> +               if (val > 255) {
> +                       addr.s_addr = 0;
> +                       return addr;
> +               }
>                 addr.s_addr <<= 8;
>                 addr.s_addr |= (val & 0xFF);
> -               if (s) {
> -                       s = (*e) ? e+1 : e;
> +               if (*e == '.') {
> +                       s = e + 1;
> +               } else if (*e == '\0') {
> +                       break;
> +               } else {
> +                       addr.s_addr = 0;
> +                       return addr;

One unintended side effect of this is that is breaks parsing of things
like 'tftpboot 192.168.1.1:zImage'. I'll fix that in the next round.

>                 }
>         }
>
> --
> 2.5.3
>