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Commit 81fbfe8a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ptr_ring: use kmalloc_array() 



As found by syzkaller, malicious users can set whatever tx_queue_len
on a tun device and eventually crash the kernel.

Lets remove the ALIGN(XXX, SMP_CACHE_BYTES) thing since a small
ring buffer is not fast anyway.

Fixes: 2e0ab8ca ("ptr_ring: array based FIFO for pointers")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 120e9dab

include/linux/ptr_ring.h

+5 −4
Original line number Diff line number Diff line
@@ -436,9 +436,9 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r, 
	__PTR_RING_PEEK_CALL_v; \

})



static inline void **__ptr_ring_init_queue_alloc(int size, gfp_t gfp)

static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)

{

	return kzalloc(ALIGN(size * sizeof(void *), SMP_CACHE_BYTES), gfp);

	return kcalloc(size, sizeof(void *), gfp);

}



static inline void __ptr_ring_set_size(struct ptr_ring *r, int size)
@@ -582,7 +582,8 @@ static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp, 
 * In particular if you consume ring in interrupt or BH context, you must

 * disable interrupts/BH when doing so.

 */

static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, int nrings,

static inline int ptr_ring_resize_multiple(struct ptr_ring **rings,

					   unsigned int nrings,

					   int size,

					   gfp_t gfp, void (*destroy)(void *))

{
@@ -590,7 +591,7 @@ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings, int nrings, 
	void ***queues;

	int i;



	queues = kmalloc(nrings * sizeof *queues, gfp);

	queues = kmalloc_array(nrings, sizeof(*queues), gfp);

	if (!queues)

		goto noqueues;

include/linux/skb_array.h

+2 −1
Original line number Diff line number Diff line
@@ -193,7 +193,8 @@ static inline int skb_array_resize(struct skb_array *a, int size, gfp_t gfp) 
}



static inline int skb_array_resize_multiple(struct skb_array **rings,

					    int nrings, int size, gfp_t gfp)

					    int nrings, unsigned int size,

					    gfp_t gfp)

{

	BUILD_BUG_ON(offsetof(struct skb_array, ring));

	return ptr_ring_resize_multiple((struct ptr_ring **)rings,