Re: [PATCH] virtio-net: make copy len check in xdp_linearize_page
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: 2021-12-13 06:25:45
On Mon, 13 Dec 2021 12:50:12 +0800, mengensun8801@gmail.com wrote:
From: mengensun <redacted> xdp_linearize_page asume ring elem size is smaller then page size when copy the first ring elem, but, there may be a elem size bigger then page size. add_recvbuf_mergeable may add a hole to ring elem, the hole size is not sure, according EWMA. so, fix it by check copy len,if checked failed, just dropped the whole frame, not make the memory dirty after the page. Signed-off-by: mengensun <redacted> Reviewed-by: MengLong Dong <redacted> Reviewed-by: ZhengXiong Jiang <redacted>
LGTM Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
quoted hunk
--- drivers/net/virtio_net.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 36a4b7c195d5..844bdbd67ff7 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c@@ -662,8 +662,12 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, int page_off, unsigned int *len) { - struct page *page = alloc_page(GFP_ATOMIC); + struct page *page; + if (*len > PAGE_SIZE - page_off) + return NULL; + + page = alloc_page(GFP_ATOMIC); if (!page) return NULL; --2.27.0
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