[U-Boot] [RFC PATCH v2 03/11] lib: net_utils: make string_to_ip stricter

[Chris Packham]

On Tue, Nov 24, 2015 at 2:06 PM, Joe Hershberger
<joe.hershberger at gmail.com> wrote:
> On Mon, Nov 9, 2015 at 1:38 AM, 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>
>> ---
>>
>> Changes in v2:
>> - restore some lazy parsing behavior that the tftpboot command relied on.
>
> It would be good to explicitly describe (in the change log) what you
> had to change about your stricter parsing that tftpboot required. It
> seems your commit log didn't change.
>

Will do. For the record it the issue was that the tftpboot code
expected to be able parse the ip address part from
'192.168.1.1:zImage'. At some point it might be worth adopting an api
like strtoul which gives you a pointer to where the parsing stopped.

>>  lib/net_utils.c | 11 ++++++++---
>>  1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/net_utils.c b/lib/net_utils.c
>> index cfae842..f148b8a 100644
>> --- a/lib/net_utils.c
>> +++ b/lib/net_utils.c
>> @@ -24,11 +24,16 @@ 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
>> +                       break;
>>         }
>>
>>         addr.s_addr = htonl(addr.s_addr);
>> --
>> 2.5.3
>>
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