[Applied] Re: [CVE-2010-4529 Dapper] irda: prevent integer underflow in IRLMP_ENUMDEVICES, CVE-2010-4529

[Leann Ogasawara]

Applied to Dapper master-next.

On Mon, 2011-03-21 at 13:17 -0700, Leann Ogasawara wrote:
> The following changes since commit 41ff5f1360cf8dd8862cabd859a0ee2199ed933b:
>   Leann Ogasawara (1):
>         econet: Fix crash in aun_incoming(). CVE-2010-4342
> 
> are available in the git repository at:
> 
>   git://kernel.ubuntu.com/ogasawara/ubuntu-dapper.git CVE-2010-4529
> 
> Dan Rosenberg (1):
>       irda: prevent integer underflow in IRLMP_ENUMDEVICES, CVE-2010-4529
> 
>  net/irda/af_irda.c |   16 +++++++++-------
>  1 files changed, 9 insertions(+), 7 deletions(-)
> 
> From cd765a405e0d70b3ddbd5befcc53fd72e0f2bf0a Mon Sep 17 00:00:00 2001
> From: Dan Rosenberg <drosenberg at vsecurity.com>
> Date: Wed, 22 Dec 2010 13:58:27 +0000
> Subject: [PATCH] irda: prevent integer underflow in IRLMP_ENUMDEVICES, CVE-2010-4529
> 
> CVE-2010-4529
> 
> BugLink: http://bugs.launchpad.net/bugs/737823
> 
> If the user-provided len is less than the expected offset, the
> IRLMP_ENUMDEVICES getsockopt will do a copy_to_user() with a very large
> size value.  While this isn't be a security issue on x86 because it will
> get caught by the access_ok() check, it may leak large amounts of kernel
> heap on other architectures.  In any event, this patch fixes it.
> 
> Signed-off-by: Dan Rosenberg <drosenberg at vsecurity.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (backport of upstream commit fdac1e0697356ac212259f2147aa60c72e334861)
> 
> Signed-off-by: Leann Ogasawara <leann.ogasawara at canonical.com>
> ---
>  net/irda/af_irda.c |   16 +++++++++-------
>  1 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
> index 36789ee..30c2b77 100644
> --- a/net/irda/af_irda.c
> +++ b/net/irda/af_irda.c
> @@ -2158,6 +2158,14 @@ static int irda_getsockopt(struct socket *sock, int level, int optname,
>  
>  	switch (optname) {
>  	case IRLMP_ENUMDEVICES:
> +
> +		/* Offset to first device entry */
> +		offset = sizeof(struct irda_device_list) -
> +			sizeof(struct irda_device_info);
> +
> +		if (len < offset)
> +			return -EINVAL;
> +
>  		/* Ask lmp for the current discovery log */
>  		discoveries = irlmp_get_discoveries(&list.len, self->mask.word,
>  						    self->nslots);
> @@ -2167,15 +2175,9 @@ static int irda_getsockopt(struct socket *sock, int level, int optname,
>  		err = 0;
>  
>  		/* Write total list length back to client */
> -		if (copy_to_user(optval, &list,
> -				 sizeof(struct irda_device_list) -
> -				 sizeof(struct irda_device_info)))
> +		if (copy_to_user(optval, &list, offset))
>  			err = -EFAULT;
>  
> -		/* Offset to first device entry */
> -		offset = sizeof(struct irda_device_list) -
> -			sizeof(struct irda_device_info);
> -
>  		/* Copy the list itself - watch for overflow */
>  		if(list.len > 2048)
>  		{
> -- 
> 1.7.0.4
> 
> 
> 
>