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* [patch] VMCI: integer overflow in vmci_datagram_dispatch()
@ 2014-08-29  8:42 Dan Carpenter
  2014-08-29 11:13 ` walter harms
  0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2014-08-29  8:42 UTC (permalink / raw)
  To: linux-kernel, George Zhang, Greg Kroah-Hartman; +Cc: kernel-janitors

This is untrusted user data from vmci_host_do_send_datagram() so the
VMCI_DG_SIZE() macro can have an integer overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
index f3cdd90..8226652 100644
--- a/drivers/misc/vmw_vmci/vmci_datagram.c
+++ b/drivers/misc/vmw_vmci/vmci_datagram.c
@@ -328,7 +328,8 @@ int vmci_datagram_dispatch(u32 context_id,
 
 	BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
 
-	if (VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
+	if (dg->payload_size > VMCI_MAX_DG_SIZE ||
+	    VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
 		pr_devel("Payload (size=%llu bytes) too big to send\n",
 			 (unsigned long long)dg->payload_size);
 		return VMCI_ERROR_INVALID_ARGS;

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [patch] VMCI: integer overflow in vmci_datagram_dispatch()
  2014-08-29  8:42 [patch] VMCI: integer overflow in vmci_datagram_dispatch() Dan Carpenter
@ 2014-08-29 11:13 ` walter harms
  2014-08-29 11:21   ` Dan Carpenter
  0 siblings, 1 reply; 3+ messages in thread
From: walter harms @ 2014-08-29 11:13 UTC (permalink / raw)
  To: Dan Carpenter
  Cc: linux-kernel, George Zhang, Greg Kroah-Hartman, kernel-janitors



Am 29.08.2014 10:42, schrieb Dan Carpenter:
> This is untrusted user data from vmci_host_do_send_datagram() so the
> VMCI_DG_SIZE() macro can have an integer overflow.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
> index f3cdd90..8226652 100644
> --- a/drivers/misc/vmw_vmci/vmci_datagram.c
> +++ b/drivers/misc/vmw_vmci/vmci_datagram.c
> @@ -328,7 +328,8 @@ int vmci_datagram_dispatch(u32 context_id,
>  
>  	BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
>  
> -	if (VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
> +	if (dg->payload_size > VMCI_MAX_DG_SIZE ||
> +	    VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
>  		pr_devel("Payload (size=%llu bytes) too big to send\n",
>  			 (unsigned long long)dg->payload_size);
>  		return VMCI_ERROR_INVALID_ARGS;

Are your sure about that ">" ? maybe ">=" was intended ?

re,
 wh

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [patch] VMCI: integer overflow in vmci_datagram_dispatch()
  2014-08-29 11:13 ` walter harms
@ 2014-08-29 11:21   ` Dan Carpenter
  0 siblings, 0 replies; 3+ messages in thread
From: Dan Carpenter @ 2014-08-29 11:21 UTC (permalink / raw)
  To: walter harms
  Cc: linux-kernel, George Zhang, Greg Kroah-Hartman, kernel-janitors

On Fri, Aug 29, 2014 at 01:13:47PM +0200, walter harms wrote:
> 
> 
> Am 29.08.2014 10:42, schrieb Dan Carpenter:
> > This is untrusted user data from vmci_host_do_send_datagram() so the
> > VMCI_DG_SIZE() macro can have an integer overflow.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
> > index f3cdd90..8226652 100644
> > --- a/drivers/misc/vmw_vmci/vmci_datagram.c
> > +++ b/drivers/misc/vmw_vmci/vmci_datagram.c
> > @@ -328,7 +328,8 @@ int vmci_datagram_dispatch(u32 context_id,
> >  
> >  	BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
> >  
> > -	if (VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
> > +	if (dg->payload_size > VMCI_MAX_DG_SIZE ||
> > +	    VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
> >  		pr_devel("Payload (size=%llu bytes) too big to send\n",
> >  			 (unsigned long long)dg->payload_size);
> >  		return VMCI_ERROR_INVALID_ARGS;
> 
> Are your sure about that ">" ? maybe ">=" was intended ?

Yes, I'm sure.  As a rule of thumb, > is used for size comparisons and
>= is used for index comparisons.

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2014-08-29 11:21 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2014-08-29  8:42 [patch] VMCI: integer overflow in vmci_datagram_dispatch() Dan Carpenter
2014-08-29 11:13 ` walter harms
2014-08-29 11:21   ` Dan Carpenter

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