From: Eric Dumazet <eduma...@google.com>

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: 2e0ab8ca83c1 ("ptr_ring: array based FIFO for pointers")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Cc: Michael S. Tsirkin <m...@redhat.com>
Cc: Jason Wang <jasow...@redhat.com>
---
 include/linux/ptr_ring.h  |    9 +++++----
 include/linux/skb_array.h |    3 ++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index d8c97ec8a8e6..37b4bb2545b3 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -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;
 
diff --git a/include/linux/skb_array.h b/include/linux/skb_array.h
index 35226cd4efb0..8621ffdeecbf 100644
--- a/include/linux/skb_array.h
+++ b/include/linux/skb_array.h
@@ -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,


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