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 EF6EA2744D for ; Sun, 20 Jul 2025 14:46:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753022765; cv=none; b=H3e6z8jWdeXFovDcDqkQFHKfFKTfzf35OnS/qcUQlYFFsnCm9I6XOxzVCDZ2IuU+xmX2ikM+wmuWVbtFE63+IiWULmmFLk648sOkY6SuMouH17eo5j5jVZAHdVycn/l2SfSFYyHePTk/AoWWmu7amvT+rxZzLqDH/wsvIGVo6Ic= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753022765; c=relaxed/simple; bh=b0GuWs9qeXc5uETWrYeJt0XBGAcTR4QBFMs2JwF6ABw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HdpakN+NXEt5zUU7eSt9UrzMYdV6BlPwbeCmo8n5yW8o6j6MGlQS+uN6Rgdo6kHpaneJ/ag4IH2iAN1qVkBdWEjqbTOrIeOC5Y6p7aTzUImOvbblKjor9EqWVDB/Nqhhvj+kwSJqELZwMgp94lU2tvEbcfHgHvyC3+VIcZKUMis= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R4uZ/BvJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R4uZ/BvJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 647E9C4CEE7; Sun, 20 Jul 2025 14:46:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753022764; bh=b0GuWs9qeXc5uETWrYeJt0XBGAcTR4QBFMs2JwF6ABw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R4uZ/BvJBHGQ1ZaS9uU2Xw0B/JCdpm0XBH9gCtrePiMj0wdS0SqOYEpLRbn+tfQED j+8WUizZQYL9ksa5GsipnIPPbhhtGuRUsB2vYs0naASsB6jN7baOhwB+C/uTCpQRqu g+vwmmtv39RkUFHHua3gLbuQ0joRtyg/WsRpqkOOXRGZGAD939QC+Lk18JeDZAh18e q2XswrkfouF7OKdx2B710NvXbMygCk2qfbP0W2OFr+4/a8YkJ13FOmsS3jsZ9QQaOg stB6zSycdj+HEwOuJh1f+UY6UX34LxefCP5q3dVAN1yKX9LnhotnO4xSFsID2y7Yx5 IIQhDF5QfimnQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Bui Quang Minh , Jason Wang , Paolo Abeni , Sasha Levin Subject: [PATCH 5.4.y] virtio-net: ensure the received length does not exceed allocated size Date: Sun, 20 Jul 2025 10:45:54 -0400 Message-Id: <20250720144554.542893-1-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <2025070649-freezing-truce-2745@gregkh> References: <2025070649-freezing-truce-2745@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Bui Quang Minh [ Upstream commit 315dbdd7cdf6aa533829774caaf4d25f1fd20e73 ] In xdp_linearize_page, when reading the following buffers from the ring, we forget to check the received length with the true allocate size. This can lead to an out-of-bound read. This commit adds that missing check. Cc: Fixes: 4941d472bf95 ("virtio-net: do not reset during XDP set") Signed-off-by: Bui Quang Minh Acked-by: Jason Wang Link: https://patch.msgid.link/20250630144212.48471-2-minhquangbui99@gmail.com Signed-off-by: Paolo Abeni [ adapted virtqueue_get_buf() to virtqueue_get_buf_ctx() ] Signed-off-by: Sasha Levin --- drivers/net/virtio_net.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 215c546bf50a9..6f82338c617e1 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -394,6 +394,26 @@ static unsigned int mergeable_ctx_to_truesize(void *mrg_ctx) return (unsigned long)mrg_ctx & ((1 << MRG_CTX_HEADER_SHIFT) - 1); } +static int check_mergeable_len(struct net_device *dev, void *mrg_ctx, + unsigned int len) +{ + unsigned int headroom, tailroom, room, truesize; + + truesize = mergeable_ctx_to_truesize(mrg_ctx); + headroom = mergeable_ctx_to_headroom(mrg_ctx); + tailroom = headroom ? sizeof(struct skb_shared_info) : 0; + room = SKB_DATA_ALIGN(headroom + tailroom); + + if (len > truesize - room) { + pr_debug("%s: rx error: len %u exceeds truesize %lu\n", + dev->name, len, (unsigned long)(truesize - room)); + dev->stats.rx_length_errors++; + return -1; + } + + return 0; +} + /* Called from bottom half context */ static struct sk_buff *page_to_skb(struct virtnet_info *vi, struct receive_queue *rq, @@ -639,7 +659,8 @@ static unsigned int virtnet_get_headroom(struct virtnet_info *vi) * across multiple buffers (num_buf > 1), and we make sure buffers * have enough headroom. */ -static struct page *xdp_linearize_page(struct receive_queue *rq, +static struct page *xdp_linearize_page(struct net_device *dev, + struct receive_queue *rq, u16 *num_buf, struct page *p, int offset, @@ -659,18 +680,27 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, memcpy(page_address(page) + page_off, page_address(p) + offset, *len); page_off += *len; + /* Only mergeable mode can go inside this while loop. In small mode, + * *num_buf == 1, so it cannot go inside. + */ while (--*num_buf) { unsigned int buflen; void *buf; + void *ctx; int off; - buf = virtqueue_get_buf(rq->vq, &buflen); + buf = virtqueue_get_buf_ctx(rq->vq, &buflen, &ctx); if (unlikely(!buf)) goto err_buf; p = virt_to_head_page(buf); off = buf - page_address(p); + if (check_mergeable_len(dev, ctx, buflen)) { + put_page(p); + goto err_buf; + } + /* guard against a misconfigured or uncooperative backend that * is sending packet larger than the MTU. */ @@ -745,7 +775,7 @@ static struct sk_buff *receive_small(struct net_device *dev, headroom = vi->hdr_len + header_offset; buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); - xdp_page = xdp_linearize_page(rq, &num_buf, page, + xdp_page = xdp_linearize_page(dev, rq, &num_buf, page, offset, header_offset, &tlen); if (!xdp_page) @@ -910,7 +940,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, if (unlikely(num_buf > 1 || headroom < virtnet_get_headroom(vi))) { /* linearize data for XDP */ - xdp_page = xdp_linearize_page(rq, &num_buf, + xdp_page = xdp_linearize_page(dev, rq, &num_buf, page, offset, VIRTIO_XDP_HEADROOM, &len); -- 2.39.5