From patchwork Wed Mar 31 21:44:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 413352 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=-21.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 647D7C43470 for ; Wed, 31 Mar 2021 22:45:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3742661007 for ; Wed, 31 Mar 2021 22:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232976AbhCaWos (ORCPT ); Wed, 31 Mar 2021 18:44:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:37992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232718AbhCaWo1 (ORCPT ); Wed, 31 Mar 2021 18:44:27 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 48D3E61075; Wed, 31 Mar 2021 22:44:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617230667; bh=yBfcXelbsR62PKT2NwaanCCwChsLT4uqAoFLOoTbdto=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OfI9elhtwCDTNmVm/qNFQGDxJQz7aHIMXYt/OlZm3zIPoOxaegbOn5NVwZItTOYxO 5NZitpiGe5BRs7VvUHEt9Q9mOrvag3XslpAb0kLn18Yla0nOf2/c5V3GcazP1mK8S8 QWfPxOfeAaNt5lzytM02TGuxfT283s5JJr1+njAa50PwQEDlfyfso5zzEyxoGMS3K0 6YWjqKSIvXCOYj3Uf/7Orf6fk09BlVe72LGXHnFYA3/hKJw27K9Ffqav+5yIT6txgB fBz6d+Zl+JLlM6z/mttMEhWtt1MHp6IpBsUNS0Sy+HJjqMZdoZ54GeyPmzrs94lFy6 xIzPrVTbESExQ== Date: Wed, 31 Mar 2021 16:44:29 -0500 From: "Gustavo A. R. Silva" To: linux-kernel@vger.kernel.org Cc: Kalle Valo , "David S. Miller" , Jakub Kicinski , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-hardening@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH v2 1/2][next] wl3501_cs: Fix out-of-bounds warning in wl3501_send_pkt Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Fix the following out-of-bounds warning by enclosing structure members daddr and saddr into new struct addr: arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [18, 23] from the object at 'sig' is out of the bounds of referenced subobject 'daddr' with type 'u8[6]' {aka 'unsigned char[6]'} at offset 11 [-Warray-bounds] Refactor the code, accordingly: $ pahole -C wl3501_md_req drivers/net/wireless/wl3501_cs.o struct wl3501_md_req { u16 next_blk; /* 0 2 */ u8 sig_id; /* 2 1 */ u8 routing; /* 3 1 */ u16 data; /* 4 2 */ u16 size; /* 6 2 */ u8 pri; /* 8 1 */ u8 service_class; /* 9 1 */ struct { u8 daddr[6]; /* 10 6 */ u8 saddr[6]; /* 16 6 */ } addr; /* 10 12 */ /* size: 22, cachelines: 1, members: 8 */ /* last cacheline: 22 bytes */ }; The problem is that the original code is trying to copy data into a couple of arrays adjacent to each other in a single call to memcpy(). Now that a new struct _addr_ enclosing those two adjacent arrays is introduced, memcpy() doesn't overrun the length of &sig.daddr[0], because the address of the new struct object _addr_ is used as destination, instead. Also, this helps with the ongoing efforts to enable -Warray-bounds and avoid confusing the compiler. Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot Build-tested-by: kernel test robot Link: https://lore.kernel.org/lkml/60641d9b.2eNLedOGSdcSoAV2%25lkp@intel.com/ Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook --- Changes in v2: - Update changelog text. - Replace a couple of magic numbers with new variable sig_addr_len. drivers/net/wireless/wl3501.h | 6 ++++-- drivers/net/wireless/wl3501_cs.c | 7 ++++--- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h index e98e04ee9a2c..ef9d605d8c88 100644 --- a/drivers/net/wireless/wl3501.h +++ b/drivers/net/wireless/wl3501.h @@ -471,8 +471,10 @@ struct wl3501_md_req { u16 size; u8 pri; u8 service_class; - u8 daddr[ETH_ALEN]; - u8 saddr[ETH_ALEN]; + struct { + u8 daddr[ETH_ALEN]; + u8 saddr[ETH_ALEN]; + } addr; }; struct wl3501_md_ind { diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c index 8ca5789c7b37..e149ef81d6cc 100644 --- a/drivers/net/wireless/wl3501_cs.c +++ b/drivers/net/wireless/wl3501_cs.c @@ -469,6 +469,7 @@ static int wl3501_send_pkt(struct wl3501_card *this, u8 *data, u16 len) struct wl3501_md_req sig = { .sig_id = WL3501_SIG_MD_REQ, }; + size_t sig_addr_len = sizeof(sig.addr); u8 *pdata = (char *)data; int rc = -EIO; @@ -484,9 +485,9 @@ static int wl3501_send_pkt(struct wl3501_card *this, u8 *data, u16 len) goto out; } rc = 0; - memcpy(&sig.daddr[0], pdata, 12); - pktlen = len - 12; - pdata += 12; + memcpy(&sig.addr, pdata, sig_addr_len); + pktlen = len - sig_addr_len; + pdata += sig_addr_len; sig.data = bf; if (((*pdata) * 256 + (*(pdata + 1))) > 1500) { u8 addr4[ETH_ALEN] = {