From 6fc72fd1565bcd7f872ad89cd0c7a60a7cf68c96 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Sun, 11 Feb 2018 11:28:12 +0800 Subject: [PATCH] ptr_ring: prevent integer overflow when calculating size [ Upstream commit 54e02162d4454a99227f520948bf4494c3d972d0 ] Switch to use dividing to prevent integer overflow when size is too big to calculate allocation size properly. Reported-by: Eric Biggers Fixes: 6e6e41c31122 ("ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE") Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/linux/ptr_ring.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h index 35d125569e68..e8b12b79a0de 100644 --- a/include/linux/ptr_ring.h +++ b/include/linux/ptr_ring.h @@ -450,7 +450,7 @@ 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) + if (size > KMALLOC_MAX_SIZE / sizeof(void *)) return NULL; return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO); }