From patchwork Wed Feb 23 02:38:50 2022 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: 12756172 X-Patchwork-Delegate: kvalo@adurom.com 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 C4ACBC433F5 for ; Wed, 23 Feb 2022 02:33:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237317AbiBWCeG (ORCPT ); Tue, 22 Feb 2022 21:34:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237420AbiBWCdE (ORCPT ); Tue, 22 Feb 2022 21:33:04 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3443354BEF; Tue, 22 Feb 2022 18:31:00 -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 ams.source.kernel.org (Postfix) with ESMTPS id D436AB81DD2; Wed, 23 Feb 2022 02:30:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB55AC340F1; Wed, 23 Feb 2022 02:30:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645583455; bh=H9zXEc7xajyp0WNLmUqmywqLWj4AFxabUZT7J4ZwI44=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pO9XXYnrCCqQPomdmANKP8O9qxTbnjx61E+exDu2XW+tnjbuSvKAKWseHRJRMhU8t 5+R5p/2OSuPBl7aTHW60WkNbnttWsgGC4mojnWOP99ZEV05EA187xYchv1l1VQ+ltU MsZ64e1DKkJZY//dOFdOlnMKrG7ulpalLxc/OlNKjBC39NVFlFpZCVq1qlkxx6MfB8 wK18E7iOXvEvB2dLkSwNLYrPwhDTxkJmOA16rguBlXYHzT8yiGMV29dLWUNcZ5Xl19 HX6C373RMnIPZ8jRkGH81+EYY2j2i17PVgRs6rpYgBgK4E3Dw7GTf+tMUr95P5iFP/ KS8HBWNzjzQ4Q== Date: Tue, 22 Feb 2022 20:38:50 -0600 From: "Gustavo A. R. Silva" To: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Kalle Valo , "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org, linux-hardening@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH 3/6][next] ath6kl: wmi: Replace one-element array with flexible-array member in struct wmi_channel_list_reply Message-ID: <30306253b1b5e6b8f5c0faba97e935eda4638020.1645583264.git.gustavoars@kernel.org> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Replace one-element array with flexible-array member in struct wmi_channel_list_reply. It's also worth noting that due to the flexible array transformation, the size of struct wmi_channel_list_reply changed, see below. Before flex-array transformation: struct wmi_channel_list_reply { u8 reserved; /* 0 1 */ u8 num_ch; /* 1 1 */ __le16 ch_list[1]; /* 2 2 */ /* size: 4, cachelines: 1, members: 3 */ /* last cacheline: 4 bytes */ }; After flex-array transformation: struct wmi_channel_list_reply { u8 reserved; /* 0 1 */ u8 num_ch; /* 1 1 */ __le16 ch_list[]; /* 2 0 */ /* size: 2, cachelines: 1, members: 3 */ /* last cacheline: 2 bytes */ }; So, the following change preserves the logic that if _len_ is at least 4 bytes in size, this is the existence of at least one channel in ch_list[] is being considered, then the execution jumps to call ath6kl_wakeup_event(wmi->parent_dev);, otherwise _len_ is 2 bytes or less and the code returns -EINVAL: - if (len < sizeof(struct wmi_channel_list_reply)) + if (len <= sizeof(struct wmi_channel_list_reply)) This issue was found with the help of Coccinelle and audited and fixed, manually. Link: https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/79 Signed-off-by: Gustavo A. R. Silva Reviewed-by: Jeff Johnson --- Hi! It'd be great if someone can confirm or comment on the following changes described in the changelog text: - if (len < sizeof(struct wmi_channel_list_reply)) + if (len <= sizeof(struct wmi_channel_list_reply)) Thanks drivers/net/wireless/ath/ath6kl/wmi.c | 2 +- drivers/net/wireless/ath/ath6kl/wmi.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/ath6kl/wmi.c b/drivers/net/wireless/ath/ath6kl/wmi.c index bdfc057c5a82..049d75f31f3c 100644 --- a/drivers/net/wireless/ath/ath6kl/wmi.c +++ b/drivers/net/wireless/ath/ath6kl/wmi.c @@ -1240,7 +1240,7 @@ static int ath6kl_wmi_ratemask_reply_rx(struct wmi *wmi, u8 *datap, int len) static int ath6kl_wmi_ch_list_reply_rx(struct wmi *wmi, u8 *datap, int len) { - if (len < sizeof(struct wmi_channel_list_reply)) + if (len <= sizeof(struct wmi_channel_list_reply)) return -EINVAL; ath6kl_wakeup_event(wmi->parent_dev); diff --git a/drivers/net/wireless/ath/ath6kl/wmi.h b/drivers/net/wireless/ath/ath6kl/wmi.h index 9e168752bec2..432e4f428a4a 100644 --- a/drivers/net/wireless/ath/ath6kl/wmi.h +++ b/drivers/net/wireless/ath/ath6kl/wmi.h @@ -1373,7 +1373,7 @@ struct wmi_channel_list_reply { u8 num_ch; /* channel in Mhz */ - __le16 ch_list[1]; + __le16 ch_list[]; } __packed; /* List of Events (target to host) */