Thank for reviewing the patch Ingo.
There was a mistake the first time round, lucky for me Arnaldo's comment
about the magic number helped me spot it. When ITU-T DTE facilities are
added to the X.25 header packet the length field has to contain n + 1
bytes where n is the number of bytes needed to hold the calling(or
called address) extension.
The kernel used to check that the maximum number of bytes/allowed-length
is 33. However as I understand the X.25 recommendation for
ITU-T specified DTE facilities to support OSI network services, the
value of n can be a maximum of 20 bytes. This makes the allowable
length 21. By co-incidence 0x21 turned out to be 33 bytes. But I meant
21 bytes. The other decimal value of 40 is the maximum number of semi-
octets in the calling address extension. (Therefore 20 octets + 1 in the
length field).
Now I just have to correct my other mistake .. all these patches have
the same subject...
Regards
Shaun
On Thu, 2006-02-16 at 15:18 +0100, Ingo Oeser wrote:
> Shaun Pereira wrote:
> > removed magic number 33 as suggested by Arnaldo
>
> But are you sure, you use the right substitute for it?
>
> > struct x25_calluserdata {
> > diff -uprN -X dontdiff linux-2.6.16-rc3-vanilla/include/net/x25.h linux-2.6.16-rc3/include/net/x25.h
> > --- linux-2.6.16-rc3-vanilla/include/net/x25.h 2006-02-16 15:26:19.000000000 +1100
> > +++ linux-2.6.16-rc3/include/net/x25.h 2006-02-16 15:31:50.000000000 +1100
> > @@ -101,9 +101,17 @@ enum {
> > #define X25_FAC_PACKET_SIZE 0x42
> > #define X25_FAC_WINDOW_SIZE 0x43
> >
> > -#define X25_MAX_FAC_LEN 20 /* Plenty to spare */
> > +#define X25_MAX_FAC_LEN 60
> > #define X25_MAX_CUD_LEN 128
> >
> > +#define X25_FAC_CALLING_AE 0xCB
> > +#define X25_FAC_CALLED_AE 0xC9
> > +
> > +#define X25_MARKER 0x00
> > +#define X25_DTE_SERVICES 0x0F
> > +#define X25_MAX_AE_LEN 40 /* Max num of semi-octets in AE - OSI Nw */
> > +#define X25_MAX_DTE_FACIL_LEN 21 /* Max length of DTE facility params */
>
> Are you sure that you don't mean 0x21 (== 33) here?
>
> > diff -uprN -X dontdiff linux-2.6.16-rc3-vanilla/net/x25/x25_facilities.c linux-2.6.16-rc3/net/x25/x25_facilities.c
> > --- linux-2.6.16-rc3-vanilla/net/x25/x25_facilities.c 2006-02-16 15:26:25.000000000 +1100
> > +++ linux-2.6.16-rc3/net/x25/x25_facilities.c 2006-02-16 15:31:50.000000000 +1100
> > @@ -112,9 +127,30 @@ int x25_parse_facilities(struct sk_buff
> > len -= 4;
> > break;
> > case X25_FAC_CLASS_D:
> > - printk(KERN_DEBUG "X.25: unknown facility %02X, "
> > - "length %d, values %02X, %02X, %02X, %02X\n",
> > - p[0], p[1], p[2], p[3], p[4], p[5]);
> > + switch (*p) {
> > + case X25_FAC_CALLING_AE:
> > + if (p[1] > X25_MAX_DTE_FACIL_LEN)
>
> Because the magic number 33 was here before ...
>
> > + break;
> > + dte_facs->calling_len = p[2];
> > + memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
> > + *vc_fac_mask |= X25_MASK_CALLING_AE;
> > + break;
> > +
> > + case X25_FAC_CALLED_AE:
> > + if (p[1] > X25_MAX_DTE_FACIL_LEN)
>
> ...and here
>
> > + break;
> > + dte_facs->called_len = p[2];
> > + memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
> > + *vc_fac_mask |= X25_MASK_CALLED_AE;
> > + break;
> > +
> > + default:
> > + printk(KERN_DEBUG "X.25: unknown facility %02X,"
> > + "length %d, values %02X, %02X, %02X, %02X\n",
> > + p[0], p[1], p[2], p[3], p[4], p[5]);
> > + break;
> > + }
> > +
> > len -= p[1] + 2;
> > p += p[1] + 2;
> > break;
>
> Regards
>
> Ingo Oeser
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