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@gmail.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@gmail.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@aerifal.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