Messages in this thread | | | Date | Wed, 18 Mar 2020 12:02:04 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] VMCI: Fix NULL pointer dereference on context ptr |
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On Tue, Mar 17, 2020 at 02:29:57PM +0800, Xiyu Yang wrote: > The refcount wrapper function vmci_ctx_get() may return NULL > context ptr. Thus, we need to add a NULL pointer check > before its dereference. > > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> > --- > drivers/misc/vmw_vmci/vmci_context.c | 2 ++ > drivers/misc/vmw_vmci/vmci_queue_pair.c | 17 +++++++++++------ > 2 files changed, 13 insertions(+), 6 deletions(-) > > diff --git a/drivers/misc/vmw_vmci/vmci_context.c b/drivers/misc/vmw_vmci/vmci_context.c > index 16695366ec92..a20878fba374 100644 > --- a/drivers/misc/vmw_vmci/vmci_context.c > +++ b/drivers/misc/vmw_vmci/vmci_context.c > @@ -898,6 +898,8 @@ void vmci_ctx_rcv_notifications_release(u32 context_id, > bool success) > { > struct vmci_ctx *context = vmci_ctx_get(context_id); > + if (context == NULL) > + return;
Same comment as on your other patch.
And is this a v2?
> > spin_lock(&context->lock); > if (!success) { > diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c > index 8531ae781195..2ecb22d08692 100644 > --- a/drivers/misc/vmw_vmci/vmci_queue_pair.c > +++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c > @@ -1575,11 +1575,14 @@ static int qp_broker_attach(struct qp_broker_entry *entry, > */ > > create_context = vmci_ctx_get(entry->create_id); > - supports_host_qp = vmci_ctx_supports_host_qp(create_context); > - vmci_ctx_put(create_context); > + if (!create_context) { > + supports_host_qp = > + vmci_ctx_supports_host_qp(create_context); > + vmci_ctx_put(create_context); > > - if (!supports_host_qp) > - return VMCI_ERROR_INVALID_RESOURCE; > + if (!supports_host_qp) > + return VMCI_ERROR_INVALID_RESOURCE; > + } > } > > if ((entry->qp.flags & ~VMCI_QP_ASYMM) != (flags & ~VMCI_QP_ASYMM_PEER)) > @@ -1808,7 +1811,8 @@ static int qp_alloc_host_work(struct vmci_handle *handle, > pr_devel("queue pair broker failed to alloc (result=%d)\n", > result); > } > - vmci_ctx_put(context); > + if (context) > + vmci_ctx_put(context);
can't vmci_ctx_put() take a NULL pointer? If not, fix this that way please.
thanks,
greg k-h
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