Messages in this thread | | | Date | Fri, 29 Aug 2014 14:21:04 +0300 | From | Dan Carpenter <> | Subject | Re: [patch] VMCI: integer overflow in vmci_datagram_dispatch() |
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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
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