From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32D7AC07E99 for ; Mon, 12 Jul 2021 08:35:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DC98610D1 for ; Mon, 12 Jul 2021 08:35:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245271AbhGLIiS (ORCPT ); Mon, 12 Jul 2021 04:38:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:35416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350683AbhGLHvN (ORCPT ); Mon, 12 Jul 2021 03:51:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5982461450; Mon, 12 Jul 2021 07:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626076057; bh=iyJJED7STGiKbuwD/N9uBYcsecrSk4aVuOy+pHuJ+58=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Stt+LbMJsvV3LlJH0cVcT0TITIXC6ZIzFHLJBouiGjOrF7JF+gokKiYfVT8gEcyLt TGIhIPGxJ4t584GfOAy/83OpltwjTXZUHoyG4Khhnrk8Ig0mk6liT8TPnXKRoVUMrL h9taPXKFUzoiU+E5eoxVHL/tTRYg3eKhj+0pF9xQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Magnus Karlsson , Daniel Borkmann , Xuan Zhuo , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Sasha Levin Subject: [PATCH 5.13 481/800] xsk: Fix broken Tx ring validation Date: Mon, 12 Jul 2021 08:08:24 +0200 Message-Id: <20210712061018.362462713@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060912.995381202@linuxfoundation.org> References: <20210712060912.995381202@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Magnus Karlsson [ Upstream commit f654fae47e83e56b454fbbfd0af0a4f232e356d6 ] Fix broken Tx ring validation for AF_XDP. The commit under the Fixes tag, fixed an off-by-one error in the validation but introduced another error. Descriptors are now let through even if they straddle a chunk boundary which they are not allowed to do in aligned mode. Worse is that they are let through even if they straddle the end of the umem itself, tricking the kernel to read data outside the allowed umem region which might or might not be mapped at all. Fix this by reintroducing the old code, but subtract the length by one to fix the off-by-one error that the original patch was addressing. The test chunk != chunk_end makes sure packets do not straddle chunk boundraries. Note that packets of zero length are allowed in the interface, therefore the test if the length is non-zero. Fixes: ac31565c2193 ("xsk: Fix for xp_aligned_validate_desc() when len == chunk_size") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Reviewed-by: Xuan Zhuo Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20210618075805.14412-1-magnus.karlsson@gmail.com Signed-off-by: Sasha Levin --- net/xdp/xsk_queue.h | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index 9d2a89d793c0..9ae13cccfb28 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -128,12 +128,15 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr) static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { - u64 chunk; - - if (desc->len > pool->chunk_size) - return false; + u64 chunk, chunk_end; chunk = xp_aligned_extract_addr(pool, desc->addr); + if (likely(desc->len)) { + chunk_end = xp_aligned_extract_addr(pool, desc->addr + desc->len - 1); + if (chunk != chunk_end) + return false; + } + if (chunk >= pool->addrs_cnt) return false; -- 2.30.2