Re: [PATCH] irda: validate peer name and attribute lengths

[Dan Rosenberg <drosenberg@vsecurity.com>]

On Sun, 2011-03-20 at 21:32 -0400, Dan Rosenberg wrote:
> Length fields provided by a peer for names and attributes may be longer
> than the destination array sizes.  Validate lengths to prevent stack
> buffer overflows.
> 

While this is the most serious bug I see, this function also seems to
lack any validation against skb->len.  If someone wants to take care of
this, by all means...if not, I'll post a follow-up patch in the next day
or so.

-Dan

> Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
> Cc: stable@kernel.org
> ---
>  net/irda/iriap.c |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
> 
> diff --git a/net/irda/iriap.c b/net/irda/iriap.c
> index 5b743bd..3647753 100644
> --- a/net/irda/iriap.c
> +++ b/net/irda/iriap.c
> @@ -656,10 +656,16 @@ static void iriap_getvaluebyclass_indication(struct iriap_cb *self,
>  	n = 1;
>  
>  	name_len = fp[n++];
> +
> +	IRDA_ASSERT(name_len < IAS_MAX_CLASSNAME + 1, return;);
> +
>  	memcpy(name, fp+n, name_len); n+=name_len;
>  	name[name_len] = '\0';
>  
>  	attr_len = fp[n++];
> +
> +	IRDA_ASSERT(attr_len < IAS_MAX_ATTRIBNAME + 1, return;);
> +
>  	memcpy(attr, fp+n, attr_len); n+=attr_len;
>  	attr[attr_len] = '\0';
>  
>