From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B89AC2108 for ; Mon, 24 Apr 2023 13:38:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2517BC433D2; Mon, 24 Apr 2023 13:38:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1682343529; bh=n1QjoW+UKH6fRW7FMS5/dogPQnv0TvaqgEn8B2GCeH4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yYTEnUVBEWwn3Q1eQWO+9joNgYPh8U9F+GHpTsXflgg5lyQ8c6JKKlPYOusbi8t5I 7IeWEV6sBAiNqAyxhNWMs0A11fdlVkRTcymiKfWAIAHOClGi/0bg4N72cs+SV2NoiZ B243pGGssmwth2V8No0v/cgaaAVriUpwFLU9pI38= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xuan Zhuo , Jason Wang , "Michael S. Tsirkin" , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 03/29] virtio_net: bugfix overflow inside xdp_linearize_page() Date: Mon, 24 Apr 2023 15:18:30 +0200 Message-Id: <20230424131121.273546556@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230424131121.155649464@linuxfoundation.org> References: <20230424131121.155649464@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Xuan Zhuo [ Upstream commit 853618d5886bf94812f31228091cd37d308230f7 ] Here we copy the data from the original buf to the new page. But we not check that it may be overflow. As long as the size received(including vnethdr) is greater than 3840 (PAGE_SIZE -VIRTIO_XDP_HEADROOM). Then the memcpy will overflow. And this is completely possible, as long as the MTU is large, such as 4096. In our test environment, this will cause crash. Since crash is caused by the written memory, it is meaningless, so I do not include it. Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers") Signed-off-by: Xuan Zhuo Acked-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/virtio_net.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 406ef4cc636d4..0cd46735e3950 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -600,8 +600,13 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, int page_off, unsigned int *len) { - struct page *page = alloc_page(GFP_ATOMIC); + int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + struct page *page; + if (page_off + *len + tailroom > PAGE_SIZE) + return NULL; + + page = alloc_page(GFP_ATOMIC); if (!page) return NULL; @@ -609,7 +614,6 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, page_off += *len; while (--*num_buf) { - int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); unsigned int buflen; void *buf; int off; -- 2.39.2