| Message ID | 1518169550-5987-1-git-send-email-jasowang@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [V4,1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE | expand |
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> Acked-by: Michael S. Tsirkin <mst@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; > return kcalloc(size, sizeof(void *), gfp); > } > > -- > 2.7.4
From: Jason Wang <jasowang@redhat.com> Date: Fri, 9 Feb 2018 17:45:49 +0800 > 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> Applied.
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
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
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; return kcalloc(size, sizeof(void *), gfp); }
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(+)