From: jiangyiwen Date: Fri, 3 Aug 2018 04:11:34 +0000 (+0800) Subject: 9p/virtio: fix off-by-one error in sg list bounds check X-Git-Tag: v4.14.69~64 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=f92953b0765bf465261782d47af6a4b38c20fa8c;p=users%2Fjedix%2Flinux-maple.git 9p/virtio: fix off-by-one error in sg list bounds check commit 23cba9cbde0bba05d772b335fe5f66aa82b9ad19 upstream. Because the value of limit is VIRTQUEUE_NUM, if index is equal to limit, it will cause sg array out of bounds, so correct the judgement of BUG_ON. Link: http://lkml.kernel.org/r/5B63D5F6.6080109@huawei.com Signed-off-by: Yiwen Jiang Reported-By: Dan Carpenter Acked-by: Jun Piao Cc: stable@vger.kernel.org Signed-off-by: Dominique Martinet Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index a03336ede2ca7..da0d3b2574593 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -189,7 +189,7 @@ static int pack_sg_list(struct scatterlist *sg, int start, s = rest_of_page(data); if (s > count) s = count; - BUG_ON(index > limit); + BUG_ON(index >= limit); /* Make sure we don't terminate early. */ sg_unmark_end(&sg[index]); sg_set_buf(&sg[index++], data, s); @@ -234,6 +234,7 @@ pack_sg_list_p(struct scatterlist *sg, int start, int limit, s = PAGE_SIZE - data_off; if (s > count) s = count; + BUG_ON(index >= limit); /* Make sure we don't terminate early. */ sg_unmark_end(&sg[index]); sg_set_page(&sg[index++], pdata[i++], s, data_off);