* [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
@ 2018-02-07 8:08 Jason Wang
2018-02-07 9:17 ` Jason Wang
2018-02-08 15:44 ` Michael S. Tsirkin
0 siblings, 2 replies; 5+ messages in thread
From: Jason Wang @ 2018-02-07 8:08 UTC (permalink / raw)
To: linux-kernel, mst; +Cc: netdev, Jason Wang
To avoid slab to warn about exceeded size, fail early if queue
occupies more than KMALLOC_MAX_SIZE.
Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
include/linux/ptr_ring.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 1883d61..4b862da 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)
{
+ if (size > KMALLOC_MAX_SIZE)
+ return NULL;
return kcalloc(size, sizeof(void *), gfp);
}
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
2018-02-07 8:08 [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE Jason Wang
@ 2018-02-07 9:17 ` Jason Wang
2018-02-07 15:15 ` Michael S. Tsirkin
2018-02-08 15:44 ` Michael S. Tsirkin
1 sibling, 1 reply; 5+ messages in thread
From: Jason Wang @ 2018-02-07 9:17 UTC (permalink / raw)
To: linux-kernel, mst; +Cc: netdev
On 2018年02月07日 16:08, Jason Wang wrote:
> To avoid slab to warn about exceeded size, fail early if queue
> occupies more than KMALLOC_MAX_SIZE.
>
> Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> include/linux/ptr_ring.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
> index 1883d61..4b862da 100644
> --- a/include/linux/ptr_ring.h
> +++ b/include/linux/ptr_ring.h
> @@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
>
> static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)
> {
> + if (size > KMALLOC_MAX_SIZE)
> + return NULL;
> return kcalloc(size, sizeof(void *), gfp);
> }
>
Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
2018-02-07 9:17 ` Jason Wang
@ 2018-02-07 15:15 ` Michael S. Tsirkin
2018-02-08 3:04 ` Jason Wang
0 siblings, 1 reply; 5+ messages in thread
From: Michael S. Tsirkin @ 2018-02-07 15:15 UTC (permalink / raw)
To: Jason Wang; +Cc: linux-kernel, netdev
On Wed, Feb 07, 2018 at 05:17:59PM +0800, Jason Wang wrote:
>
>
> On 2018年02月07日 16:08, Jason Wang wrote:
> > To avoid slab to warn about exceeded size, fail early if queue
> > occupies more than KMALLOC_MAX_SIZE.
> >
> > Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> > include/linux/ptr_ring.h | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
> > index 1883d61..4b862da 100644
> > --- a/include/linux/ptr_ring.h
> > +++ b/include/linux/ptr_ring.h
> > @@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
> > static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)
> > {
> > + if (size > KMALLOC_MAX_SIZE)
> > + return NULL;
> > return kcalloc(size, sizeof(void *), gfp);
> > }
>
> Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
That's probably not enough. How about switching to kvmalloc and limiting
this drastically to e.g. 64K. I vaguely remember that some wise man said
that should be enough for everybody :)
--
MST
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
2018-02-07 15:15 ` Michael S. Tsirkin
@ 2018-02-08 3:04 ` Jason Wang
0 siblings, 0 replies; 5+ messages in thread
From: Jason Wang @ 2018-02-08 3:04 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: linux-kernel, netdev
On 2018年02月07日 23:15, Michael S. Tsirkin wrote:
> On Wed, Feb 07, 2018 at 05:17:59PM +0800, Jason Wang wrote:
>>
>> On 2018年02月07日 16:08, Jason Wang wrote:
>>> To avoid slab to warn about exceeded size, fail early if queue
>>> occupies more than KMALLOC_MAX_SIZE.
>>>
>>> Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>> ---
>>> include/linux/ptr_ring.h | 2 ++
>>> 1 file changed, 2 insertions(+)
>>>
>>> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
>>> index 1883d61..4b862da 100644
>>> --- a/include/linux/ptr_ring.h
>>> +++ b/include/linux/ptr_ring.h
>>> @@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
>>> static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)
>>> {
>>> + if (size > KMALLOC_MAX_SIZE)
>>> + return NULL;
>>> return kcalloc(size, sizeof(void *), gfp);
>>> }
>> Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
> That's probably not enough. How about switching to kvmalloc and limiting
> this drastically to e.g. 64K. I vaguely remember that some wise man said
> that should be enough for everybody :)
>
Okay, let me post a V2 to see if there's any objection.
Thanks
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
2018-02-07 8:08 [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE Jason Wang
2018-02-07 9:17 ` Jason Wang
@ 2018-02-08 15:44 ` Michael S. Tsirkin
1 sibling, 0 replies; 5+ messages in thread
From: Michael S. Tsirkin @ 2018-02-08 15:44 UTC (permalink / raw)
To: Jason Wang; +Cc: linux-kernel, netdev
On Wed, Feb 07, 2018 at 04:08:25PM +0800, Jason Wang wrote:
> To avoid slab to warn about exceeded size, fail early if queue
> occupies more than KMALLOC_MAX_SIZE.
>
> Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> include/linux/ptr_ring.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
> index 1883d61..4b862da 100644
> --- a/include/linux/ptr_ring.h
> +++ b/include/linux/ptr_ring.h
> @@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
>
> static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)
> {
> + if (size > KMALLOC_MAX_SIZE)
> + return NULL;
> return kcalloc(size, sizeof(void *), gfp);
> }
I guess this approach does begin to make more sense
at least as a temporary stop-gap.
But does this actually prevent the crash in all cases?
size is in void* entry units, KMALLOC_MAX_SIZE is in bytes.
>
> --
> 2.7.4
^ permalink raw reply [flat|nested] 5+ messages in thread
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2018-02-07 8:08 [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE Jason Wang
2018-02-07 9:17 ` Jason Wang
2018-02-07 15:15 ` Michael S. Tsirkin
2018-02-08 3:04 ` Jason Wang
2018-02-08 15:44 ` Michael S. Tsirkin
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