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Message-ID: <CAKHv7phimitBuX=LNS_vv7sfaGNHPXy+tRSSq1sBsC=0CRyauw@mail.gmail.com>
Date: Sun, 20 Oct 2013 17:30:01 +0200
From: Paul Schutte <sjpschutte@...il.com>
To: musl@...ts.openwall.com
Subject: Re: inet_pton problem
Hi,
My previous attempt still left the door open for the ":192.168.1.1" case to
sneak through.
The following handled everything I could dream up correctly:
--- a/musl/src/network/inet_pton.c
+++ b/musl/src/network/inet_pton.c
@@ -14,11 +14,11 @@
return -1;
}
-int inet_pton(int af, const char *restrict s, void *restrict a0)
+int inet_pton(int af, const char *restrict s0, void *restrict a0)
{
uint16_t ip[8];
unsigned char *a = a0;
- const char *z;
+ const char *z,*s = s0;
unsigned long x;
int i, j, v, d, brk=-1, need_v4=0;
@@ -73,6 +73,10 @@
*a++ = ip[j]>>8;
*a++ = ip[j];
}
+
+ /* IPv4 dotted-quad should have valid IPv6 in front*/
+ if ((s-s0) <2) return 0;
+
if (need_v4 && inet_pton(AF_INET, (void *)s, a-4) <= 0) return 0;
return 1;
}
On Sun, Oct 20, 2013 at 2:26 PM, Paul Schutte <sjpschutte@...il.com> wrote:
> Hi Rich,
>
> Unfortunately this is not the complete fix.
>
> Haproxy still complains about invalid networks.
>
> The following seems to fix the problem without adding too much bloat:
>
> --- a/musl/src/network/inet_pton.c
> +++ b/musl/src/network/inet_pton.c
> @@ -14,11 +14,11 @@
> return -1;
> }
>
> -int inet_pton(int af, const char *restrict s, void *restrict a0)
> +int inet_pton(int af, const char *restrict s0, void *restrict a0)
> {
> uint16_t ip[8];
> unsigned char *a = a0;
> - const char *z;
> + const char *z,*s = s0;
> unsigned long x;
> int i, j, v, d, brk=-1, need_v4=0;
>
> @@ -73,6 +73,10 @@
> *a++ = ip[j]>>8;
> *a++ = ip[j];
> }
> +
> + /* There must have been valid IPv6 preceding IPv4 dotted-quad */
> + if (s==s0) return 0;
> +
> if (need_v4 && inet_pton(AF_INET, (void *)s, a-4) <= 0) return 0;
> return 1;
> }
>
>
>
> Regards
> Paul
>
>
>
> On Sun, Oct 20, 2013 at 11:50 AM, Paul Schutte <sjpschutte@...il.com>wrote:
>
>> Hi Rich,
>>
>> I agree with you, especially about the bloat part.
>>
>> They (haproxy) actually use this function to determine whether the
>> address they have is a valid IPv6 address.
>> They pass in either a valid IPv4 or IPv6 address and then rely on this
>> function to determine which they have (assuming a return value of 0).
>>
>> After reading the spec more carefully I realise that -1 should be
>> returned only when the address family is not AF_INET or AF_INET6.
>>
>> By changing the return value in the IPv6 code to 0 instead of -1, we
>> could get the correct behaviour without any extra code.
>>
>> Here is a patch to try and save you a bit of work:
>>
>> --- a/musl/src/network/inet_pton.c
>> +++ b/musl/src/network/inet_pton.c
>> @@ -46,24 +46,24 @@
>> if (!s[1]) break;
>> continue;
>> }
>> - if (hexval(s[0])<0) return -1;
>> + if (hexval(s[0])<0) return 0;
>> while (s[0]=='0' && s[1]=='0') s++;
>> for (v=j=0; j<5 && (d=hexval(s[j]))>=0; j++)
>> v=16*v+d;
>> - if (v > 65535) return -1;
>> + if (v > 65535) return 0;
>> ip[i] = v;
>> if (!s[j]) {
>> - if (brk<0 && i!=7) return -1;
>> + if (brk<0 && i!=7) return 0;
>> break;
>> }
>> if (i<7) {
>> if (s[j]==':') continue;
>> - if (s[j]!='.') return -1;
>> + if (s[j]!='.') return 0;
>> need_v4=1;
>> i++;
>> break;
>> }
>> - return -1;
>> + return 0;
>> }
>> if (brk>=0) {
>> memmove(ip+brk+7-i, ip+brk, 2*(i+1-brk));
>> @@ -73,6 +73,6 @@
>> *a++ = ip[j]>>8;
>> *a++ = ip[j];
>> }
>> - if (need_v4 &&inet_pton(AF_INET, (void *)s, a-4) <= 0) return -1;
>> + if (need_v4 &&inet_pton(AF_INET, (void *)s, a-4) <= 0) return 0;
>> return 1;
>> }
>>
>> Regards
>> Paul
>>
>>
>>
>> On Sun, Oct 20, 2013 at 4:22 AM, Rich Felker <dalias@...ifal.cx> wrote:
>>
>>> On Sat, Oct 19, 2013 at 10:57:00PM +0200, Paul Schutte wrote:
>>> > Hi,
>>> >
>>> > I came across this and believe it is a bug.
>>> >
>>> > I have found that when you set str to an IPv4 addr of the from
>>> > "xxx.xxx.xxx.xxx' while the address family is AF_INET6, then instead of
>>> > returning a 0 to indicate an invalid IPv6 string, it is converted to
>>> > gibberish.
>>>
>>> From what I can tell, it's not converted to gibberish; instead, it's
>>> wrongly returning an error (-1) instead of a result indicating an
>>> invalid input string (0). One could argue that it's a programming
>>> error not to check this, but inet_pton should not have any reason to
>>> return -1 if the first argument (af) is valid, so one could also argue
>>> that such checks would be extraneous bloat.
>>>
>>> > inet_pton(AF_INET6, "192.168.1.1', &sa) should return 0 if I
>>> understand the
>>> > specification correctly.
>>>
>>> Agreed.
>>>
>>> Rich
>>>
>>
>>
>
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