From patchwork Wed Apr 14 23:43:19 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: 422177 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 BF7DAC433B4 for ; Wed, 14 Apr 2021 23:43:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B05061154 for ; Wed, 14 Apr 2021 23:43:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229617AbhDNXnb (ORCPT ); Wed, 14 Apr 2021 19:43:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:53190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229573AbhDNXna (ORCPT ); Wed, 14 Apr 2021 19:43:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7C09361154; Wed, 14 Apr 2021 23:43:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618443788; bh=JNrMDRE8+SHDf4AlN0wA82GsuaVAEYDwobfrD9UBR3Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UEQdFDb3e8h/3oDGh4gzDk8zuesSAdsTw5hVmBvOhtc3pkl4jolHMnk7m0X7RfC7t E6saAXOFdCPZEc4uwiBux9OZuhbSGq+dUfCT073XAgm3+1beAPUj84s9iEIP+KOK/r GCQxGrOQW76f/fROw+/n2jWjewK4gbxkmD3ZtUlZmB/ZS9SDk1F682upGsxwlsfgZ5 qaMWquwQKG5GDZVlySTxPJQTpIhYNCUtF5ty6fKq6CTiZntgpFmfNVJogKFlj4knSv MoON3o9AXy4M7qrfhqi/z3uObS6uVuNME1hCNBl7jBskhLqRipHGmhphHkg+0KxVl9 fLueoyb0jp17A== Date: Wed, 14 Apr 2021 18:43:19 -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" , Kees Cook Subject: [PATCH v3 1/2] wl3501_cs: Fix out-of-bounds warnings in wl3501_send_pkt Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Fix the following out-of-bounds warnings by enclosing structure members daddr and saddr into new struct addr, in structures wl3501_md_req and wl3501_md_ind: 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] 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 */ }; $ pahole -C wl3501_md_ind drivers/net/wireless/wl3501_cs.o struct wl3501_md_ind { u16 next_blk; /* 0 2 */ u8 sig_id; /* 2 1 */ u8 routing; /* 3 1 */ u16 data; /* 4 2 */ u16 size; /* 6 2 */ u8 reception; /* 8 1 */ u8 pri; /* 9 1 */ u8 service_class; /* 10 1 */ struct { u8 daddr[6]; /* 11 6 */ u8 saddr[6]; /* 17 6 */ } addr; /* 11 12 */ /* size: 24, cachelines: 1, members: 9 */ /* padding: 1 */ /* last cacheline: 24 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] and &sig.daddr, because the address of the new struct object _addr_ is used, instead. This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot Reviewed-by: Kees Cook Signed-off-by: Gustavo A. R. Silva --- Changes in v3: - Enclose adjacent members in struct wl3501_md_ind into new struct req. - Fix one more instance of this same issue in function wl3501_md_ind_interrupt(). - Update changelog text. - Add Kees' RB tag. Changes in v2: - Update changelog text. - Replace a couple of magic numbers with new variable sig_addr_len. drivers/net/wireless/wl3501.h | 12 ++++++++---- drivers/net/wireless/wl3501_cs.c | 10 ++++++---- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h index e98e04ee9a2c..aa8222cbea68 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 { @@ -484,8 +486,10 @@ struct wl3501_md_ind { u8 reception; 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_confirm { diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c index 8ca5789c7b37..70307308635f 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] = { @@ -980,7 +981,8 @@ static inline void wl3501_md_ind_interrupt(struct net_device *dev, } else { skb->dev = dev; skb_reserve(skb, 2); /* IP headers on 16 bytes boundaries */ - skb_copy_to_linear_data(skb, (unsigned char *)&sig.daddr, 12); + skb_copy_to_linear_data(skb, (unsigned char *)&sig.addr, + sizeof(sig.addr)); wl3501_receive(this, skb->data, pkt_len); skb_put(skb, pkt_len); skb->protocol = eth_type_trans(skb, dev);