Messages in this thread | | | Date | Sat, 10 Feb 2018 11:32:01 -0800 | From | Eric Biggers <> | Subject | Re: [PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE |
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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
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