Re: [PATCH] Fix an inproper alignment accessing in irda protocol stack

[Luke Yang]

Hi all,

 There is another same unaligend issue in irda stack to be fixed:

Signed-off-by: Luke Yang <luke.adi@xxxxxxxxx>

--- linux-2.6.x/net/irda/discovery.c    2006-03-22 18:32:37.000000000 +0800
+++ ../../uClinux-dist/linux-2.6.x/net/irda/discovery.c 2006-06-30
18:07:46.000000000 +0800
@@ -38,6 +38,7 @@
#include <net/irda/irlmp.h>

#include <net/irda/discovery.h>
+#include <asm/unaligned.h>

/*
 * Function irlmp_add_discovery (cachelog, discovery)
@@ -86,7 +87,7 @@
                        */
                       hashbin_remove_this(cachelog, (irda_queue_t *) node);
                       /* Check if hints bits are unchanged */
-                       if(u16ho(node->data.hints) == u16ho(new->data.hints))
+                       if(get_unaligned(node->data.hints) ==
get_unaligned(new->data.hints))
                               /* Set time of first discovery for this node */
                               new->firststamp = node->firststamp;
                       kfree(node);
@@ -280,7 +281,7 @@
               /* Mask out the ones we don't want :
                * We want to match the discovery mask, and to get only
                * the most recent one (unless we want old ones) */
-               if ((u16ho(discovery->data.hints) & mask) &&
+               if ((get_unaligned(discovery->data.hints) & mask) &&
                   ((old_entries) ||
                    ((jiffies - discovery->firststamp) < j_timeout)) ) {
                       /* Create buffer as needed.


Regards,
Luke Yang

On 6/18/06, David Miller <davem@xxxxxxxxxxxxx> wrote:
> From: "Luke Yang" <luke.adi@xxxxxxxxx>
> Date: Wed, 14 Jun 2006 10:29:19 +0800
>
> > --- net/irda/irlmp.c.old        2006-06-08 14:49:20.000000000 +0800
> > +++ net/irda/irlmp.c    2006-06-14 10:00:22.000000000 +0800
> > @@ -849,7 +849,10 @@
> >         }
> >
> >         /* Construct new discovery info to be used by IrLAP, */
> > -       u16ho(irlmp->discovery_cmd.data.hints) = irlmp->hints.word;
> > +       irlmp->discovery_cmd.data.hints[0] = \
> > +               le16_to_cpu(irlmp->hints.word) & 0xff;
> > +       irlmp->discovery_cmd.data.hints[1] = \
> > +               (le16_to_cpu(irlmp->hints.word) & 0xff00) >> 8;
> >
> >         /*
> >          *  Set character set for device name (we use ASCII), and
>
> I decided in the end to fix this differently.
>
> We have a portable unaligned access interface, via get_unaligned() and
> put_unaligned() in asm/unaligned.h, which makes sure there is no
> penalty for platforms whose cpu does unaligned memory accesses
> transparently.
>
> diff --git a/net/irda/irlmp.c b/net/irda/irlmp.c
> index c19e9ce..57ea160 100644
> --- a/net/irda/irlmp.c
> +++ b/net/irda/irlmp.c
> @@ -44,6 +44,8 @@
>  #include <net/irda/irlmp.h>
>  #include <net/irda/irlmp_frame.h>
>
> +#include <asm/unaligned.h>
> +
>  static __u8 irlmp_find_free_slsap(void);
>  static int irlmp_slsap_inuse(__u8 slsap_sel);
>
> @@ -840,6 +842,7 @@ void irlmp_do_expiry(void)
>  void irlmp_do_discovery(int nslots)
>  {
>         struct lap_cb *lap;
> +       __u16 *data_hintsp;
>
>         /* Make sure the value is sane */
>         if ((nslots != 1) && (nslots != 6) && (nslots != 8) && (nslots != 16)){
> @@ -849,7 +852,8 @@ void irlmp_do_discovery(int nslots)
>         }
>
>         /* Construct new discovery info to be used by IrLAP, */
> -       u16ho(irlmp->discovery_cmd.data.hints) = irlmp->hints.word;
> +       data_hintsp = (__u16 *) irlmp->discovery_cmd.data.hints;
> +       put_unaligned(irlmp->hints.word, data_hintsp);
>
>         /*
>          *  Set character set for device name (we use ASCII), and


--
Best regards,
Luke Yang
luke.adi@xxxxxxxxx
-
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