* [PATCH] PCI/hotplug: fix potential null pointer deference
@ 2019-06-14 12:41 Young Xiao
2019-06-14 13:56 ` Andy Shevchenko
0 siblings, 1 reply; 3+ messages in thread
From: Young Xiao @ 2019-06-14 12:41 UTC (permalink / raw)
To: bhelgaas, tyreld, andy.shevchenko, linux-pci, linux-kernel; +Cc: Young Xiao
There is otherwise a risk of a null pointer dereference.
Signed-off-by: Young Xiao <92siuyang@gmail.com>
---
drivers/pci/hotplug/cpqphp_ctrl.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/hotplug/cpqphp_ctrl.c b/drivers/pci/hotplug/cpqphp_ctrl.c
index b7f4e1f..3c8399f 100644
--- a/drivers/pci/hotplug/cpqphp_ctrl.c
+++ b/drivers/pci/hotplug/cpqphp_ctrl.c
@@ -598,10 +598,11 @@ static struct pci_resource *get_io_resource(struct pci_resource **head, u32 size
*head = node->next;
} else {
prevnode = *head;
- while (prevnode->next != node)
+ while (prevnode && prevnode->next != node)
prevnode = prevnode->next;
- prevnode->next = node->next;
+ if (prevnode)
+ prevnode->next = node->next;
}
node->next = NULL;
break;
@@ -788,10 +789,11 @@ static struct pci_resource *get_resource(struct pci_resource **head, u32 size)
*head = node->next;
} else {
prevnode = *head;
- while (prevnode->next != node)
+ while (prevnode && prevnode->next != node)
prevnode = prevnode->next;
- prevnode->next = node->next;
+ if (prevnode)
+ prevnode->next = node->next;
}
node->next = NULL;
break;
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] PCI/hotplug: fix potential null pointer deference
2019-06-14 12:41 [PATCH] PCI/hotplug: fix potential null pointer deference Young Xiao
@ 2019-06-14 13:56 ` Andy Shevchenko
2019-08-02 0:14 ` Bjorn Helgaas
0 siblings, 1 reply; 3+ messages in thread
From: Andy Shevchenko @ 2019-06-14 13:56 UTC (permalink / raw)
To: Young Xiao
Cc: Bjorn Helgaas, Tyrel Datwyler, linux-pci,
Linux Kernel Mailing List
On Fri, Jun 14, 2019 at 3:40 PM Young Xiao <92siuyang@gmail.com> wrote:
>
> There is otherwise a risk of a null pointer dereference.
Had you analyze the code?
How come that prevnode can become NULL?
> Signed-off-by: Young Xiao <92siuyang@gmail.com>
> ---
> drivers/pci/hotplug/cpqphp_ctrl.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/hotplug/cpqphp_ctrl.c b/drivers/pci/hotplug/cpqphp_ctrl.c
> index b7f4e1f..3c8399f 100644
> --- a/drivers/pci/hotplug/cpqphp_ctrl.c
> +++ b/drivers/pci/hotplug/cpqphp_ctrl.c
> @@ -598,10 +598,11 @@ static struct pci_resource *get_io_resource(struct pci_resource **head, u32 size
> *head = node->next;
> } else {
> prevnode = *head;
> - while (prevnode->next != node)
> + while (prevnode && prevnode->next != node)
> prevnode = prevnode->next;
>
> - prevnode->next = node->next;
> + if (prevnode)
> + prevnode->next = node->next;
> }
> node->next = NULL;
> break;
> @@ -788,10 +789,11 @@ static struct pci_resource *get_resource(struct pci_resource **head, u32 size)
> *head = node->next;
> } else {
> prevnode = *head;
> - while (prevnode->next != node)
> + while (prevnode && prevnode->next != node)
> prevnode = prevnode->next;
>
> - prevnode->next = node->next;
> + if (prevnode)
> + prevnode->next = node->next;
> }
> node->next = NULL;
> break;
> --
> 2.7.4
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] PCI/hotplug: fix potential null pointer deference
2019-06-14 13:56 ` Andy Shevchenko
@ 2019-08-02 0:14 ` Bjorn Helgaas
0 siblings, 0 replies; 3+ messages in thread
From: Bjorn Helgaas @ 2019-08-02 0:14 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Young Xiao, Tyrel Datwyler, linux-pci, Linux Kernel Mailing List
On Fri, Jun 14, 2019 at 04:56:32PM +0300, Andy Shevchenko wrote:
> On Fri, Jun 14, 2019 at 3:40 PM Young Xiao <92siuyang@gmail.com> wrote:
> >
> > There is otherwise a risk of a null pointer dereference.
>
> Had you analyze the code?
> How come that prevnode can become NULL?
Dropping this for now. Young, if there's a scenario where prevnode
can actually be NULL, please mention that in the changelog and repost
this.
> > Signed-off-by: Young Xiao <92siuyang@gmail.com>
> > ---
> > drivers/pci/hotplug/cpqphp_ctrl.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/hotplug/cpqphp_ctrl.c b/drivers/pci/hotplug/cpqphp_ctrl.c
> > index b7f4e1f..3c8399f 100644
> > --- a/drivers/pci/hotplug/cpqphp_ctrl.c
> > +++ b/drivers/pci/hotplug/cpqphp_ctrl.c
> > @@ -598,10 +598,11 @@ static struct pci_resource *get_io_resource(struct pci_resource **head, u32 size
> > *head = node->next;
> > } else {
> > prevnode = *head;
> > - while (prevnode->next != node)
> > + while (prevnode && prevnode->next != node)
> > prevnode = prevnode->next;
> >
> > - prevnode->next = node->next;
> > + if (prevnode)
> > + prevnode->next = node->next;
> > }
> > node->next = NULL;
> > break;
> > @@ -788,10 +789,11 @@ static struct pci_resource *get_resource(struct pci_resource **head, u32 size)
> > *head = node->next;
> > } else {
> > prevnode = *head;
> > - while (prevnode->next != node)
> > + while (prevnode && prevnode->next != node)
> > prevnode = prevnode->next;
> >
> > - prevnode->next = node->next;
> > + if (prevnode)
> > + prevnode->next = node->next;
> > }
> > node->next = NULL;
> > break;
> > --
> > 2.7.4
> >
>
>
> --
> With Best Regards,
> Andy Shevchenko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-06-14 13:56 ` Andy Shevchenko
2019-08-02 0:14 ` Bjorn Helgaas
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