Re: [PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
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+e4d4f9ddd42955397...@syzkaller.appspotmail.com Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") Signed-off-by: Jason Wang --- 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 0x4000? 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
Re: [PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
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+e4d4f9ddd42955397...@syzkaller.appspotmail.com > Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") > Signed-off-by: Jason Wang > --- > 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 0x4000? The proper way to write this (safe from integer overflow) would be: if (size > KMALLOC_MAX_SIZE / sizeof(void *)) return NULL; - Eric
Re: [PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
From: Jason Wang 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+e4d4f9ddd42955397...@syzkaller.appspotmail.com > Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") > Signed-off-by: Jason Wang Applied.
Re: [PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
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+e4d4f9ddd42955397...@syzkaller.appspotmail.com > Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") > Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin > --- > 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
[PATCH V4 1/2] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE
To avoid slab to warn about exceeded size, fail early if queue occupies more than KMALLOC_MAX_SIZE. Reported-by: syzbot+e4d4f9ddd42955397...@syzkaller.appspotmail.com Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") Signed-off-by: Jason Wang --- 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