lkml.org 
[lkml]   [2018]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
From
Date


On 2018年02月11日 03:32, Eric Biggers wrote:
> Hi Jason,
>
> On Fri, Feb 09, 2018 at 05:45:49PM +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
>> Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
>> 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..6051a5f 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 * sizeof(void *) > KMALLOC_MAX_SIZE)
>> + return NULL;
> Are you sure that size can't be over 0x40000000? The proper way to write this
> (safe from integer overflow) would be:
>
> if (size > KMALLOC_MAX_SIZE / sizeof(void *))
> return NULL;
>
> - Eric

Good catch.

Will post a fix.

Thanks

\
 
 \ /
  Last update: 2018-02-11 03:47    [W:0.073 / U:1.012 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site