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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55155C433F5 for ; Wed, 2 Feb 2022 05:06:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240084AbiBBFGv (ORCPT ); Wed, 2 Feb 2022 00:06:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231476AbiBBFGn (ORCPT ); Wed, 2 Feb 2022 00:06:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACEA0C061714 for ; Tue, 1 Feb 2022 21:06:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4B8566172F for ; Wed, 2 Feb 2022 05:06:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1899C340EC; Wed, 2 Feb 2022 05:06:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643778402; bh=k0lMfO1n2mlXjBLMfiP08u56wmCjnCxIAt9DQjqzDkY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=COOA/fgaDZxFcnmpsPmfIfy/h5JSr+abq5IJZPrsCD/4WQQW/ELGcTM3czJfuEsHZ rBPloV8WpekVtgCVsbbjoAvc81rgmO5lHUp5UmS+In6O0vMNGDljlGlVALBNvD9GCv +P5YyeKHRqxmn6DJqKJlqlojfiYY1N8tgmzV2e6iOEFciA/sOdKziNtm7Iw/g89mBR 3rS5+FkgFmkhSmFmwsSHm4F6OlcEmJGv0xSCLo7QnSWAFFP/nJgPaypFVuewPJYkPh Z+2b7rsbe8I/hTPHJhGmsxrUuGFv99boZa8buPDkK2F9TiE0amoh4uIv/Wj7dI/vXj MGmVl0SDu/Lzg== From: Saeed Mahameed To: "David S. Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Kees Cook , Saeed Mahameed Subject: [net 18/18] net/mlx5e: Avoid field-overflowing memcpy() Date: Tue, 1 Feb 2022 21:04:04 -0800 Message-Id: <20220202050404.100122-19-saeed@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220202050404.100122-1-saeed@kernel.org> References: <20220202050404.100122-1-saeed@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Kees Cook In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Use flexible arrays instead of zero-element arrays (which look like they are always overflowing) and split the cross-field memcpy() into two halves that can be appropriately bounds-checked by the compiler. We were doing: #define ETH_HLEN 14 #define VLAN_HLEN 4 ... #define MLX5E_XDP_MIN_INLINE (ETH_HLEN + VLAN_HLEN) ... struct mlx5e_tx_wqe *wqe = mlx5_wq_cyc_get_wqe(wq, pi); ... struct mlx5_wqe_eth_seg *eseg = &wqe->eth; struct mlx5_wqe_data_seg *dseg = wqe->data; ... memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE); target is wqe->eth.inline_hdr.start (which the compiler sees as being 2 bytes in size), but copying 18, intending to write across start (really vlan_tci, 2 bytes). The remaining 16 bytes get written into wqe->data[0], covering byte_count (4 bytes), lkey (4 bytes), and addr (8 bytes). struct mlx5e_tx_wqe { struct mlx5_wqe_ctrl_seg ctrl; /* 0 16 */ struct mlx5_wqe_eth_seg eth; /* 16 16 */ struct mlx5_wqe_data_seg data[]; /* 32 0 */ /* size: 32, cachelines: 1, members: 3 */ /* last cacheline: 32 bytes */ }; struct mlx5_wqe_eth_seg { u8 swp_outer_l4_offset; /* 0 1 */ u8 swp_outer_l3_offset; /* 1 1 */ u8 swp_inner_l4_offset; /* 2 1 */ u8 swp_inner_l3_offset; /* 3 1 */ u8 cs_flags; /* 4 1 */ u8 swp_flags; /* 5 1 */ __be16 mss; /* 6 2 */ __be32 flow_table_metadata; /* 8 4 */ union { struct { __be16 sz; /* 12 2 */ u8 start[2]; /* 14 2 */ } inline_hdr; /* 12 4 */ struct { __be16 type; /* 12 2 */ __be16 vlan_tci; /* 14 2 */ } insert; /* 12 4 */ __be32 trailer; /* 12 4 */ }; /* 12 4 */ /* size: 16, cachelines: 1, members: 9 */ /* last cacheline: 16 bytes */ }; struct mlx5_wqe_data_seg { __be32 byte_count; /* 0 4 */ __be32 lkey; /* 4 4 */ __be64 addr; /* 8 8 */ /* size: 16, cachelines: 1, members: 3 */ /* last cacheline: 16 bytes */ }; So, split the memcpy() so the compiler can reason about the buffer sizes. "pahole" shows no size nor member offset changes to struct mlx5e_tx_wqe nor struct mlx5e_umr_wqe. "objdump -d" shows no meaningful object code changes (i.e. only source line number induced differences and optimizations). Fixes: b5503b994ed5 ("net/mlx5e: XDP TX forwarding support") Signed-off-by: Kees Cook Signed-off-by: Saeed Mahameed --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 6 +++--- drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 4 +++- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 812e6810cb3b..c14e06ca64d8 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -224,7 +224,7 @@ static inline int mlx5e_get_max_num_channels(struct mlx5_core_dev *mdev) struct mlx5e_tx_wqe { struct mlx5_wqe_ctrl_seg ctrl; struct mlx5_wqe_eth_seg eth; - struct mlx5_wqe_data_seg data[0]; + struct mlx5_wqe_data_seg data[]; }; struct mlx5e_rx_wqe_ll { @@ -241,8 +241,8 @@ struct mlx5e_umr_wqe { struct mlx5_wqe_umr_ctrl_seg uctrl; struct mlx5_mkey_seg mkc; union { - struct mlx5_mtt inline_mtts[0]; - struct mlx5_klm inline_klms[0]; + DECLARE_FLEX_ARRAY(struct mlx5_mtt, inline_mtts); + DECLARE_FLEX_ARRAY(struct mlx5_klm, inline_klms); }; }; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c index 338d65e2c9ce..56e10c84a706 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c @@ -341,8 +341,10 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd, /* copy the inline part if required */ if (sq->min_inline_mode != MLX5_INLINE_MODE_NONE) { - memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE); + memcpy(eseg->inline_hdr.start, xdptxd->data, sizeof(eseg->inline_hdr.start)); eseg->inline_hdr.sz = cpu_to_be16(MLX5E_XDP_MIN_INLINE); + memcpy(dseg, xdptxd->data + sizeof(eseg->inline_hdr.start), + MLX5E_XDP_MIN_INLINE - sizeof(eseg->inline_hdr.start)); dma_len -= MLX5E_XDP_MIN_INLINE; dma_addr += MLX5E_XDP_MIN_INLINE; dseg++; -- 2.34.1