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 9317DC7618A for ; Wed, 15 Mar 2023 20:22:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232981AbjCOUWh (ORCPT ); Wed, 15 Mar 2023 16:22:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232812AbjCOUWd (ORCPT ); Wed, 15 Mar 2023 16:22:33 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C43A9A0F34; Wed, 15 Mar 2023 13:22:22 -0700 (PDT) Received: from fpc.intra.ispras.ru (unknown [10.10.165.16]) by mail.ispras.ru (Postfix) with ESMTPSA id B6F5E44C1011; Wed, 15 Mar 2023 20:22:20 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru B6F5E44C1011 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1678911740; bh=OrnpI5NnHl+YmfKjeyUc8fbO91ALa8VLak03DsUl8sY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qoRg1+hQUtvvsjxslFN50LmZFPjj1sU/YtGyrYoBzGx8lrHunJ5uyZfMyiP+WStSZ 68sT46/hEdpFbadO4pcLfu8UoA46W0wMGWUWDH+mrERu8NVnMgrBhhOvJAyKvABCAd a97RF7oquPObq2LzTga6ggECjDqejZla2fKe9ILI= From: Fedor Pchelkin To: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Cc: Fedor Pchelkin , Kalle Valo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Senthil Balasubramanian , "John W. Linville" , Vasanthakumar Thiagarajan , Sujith , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexey Khoroshilov , lvc-project@linuxtesting.org, syzbot+df61b36319e045c00a08@syzkaller.appspotmail.com Subject: [PATCH 2/3] wifi: ath9k: fix races between ath9k_wmi_cmd and ath9k_wmi_ctrl_rx Date: Wed, 15 Mar 2023 23:21:11 +0300 Message-Id: <20230315202112.163012-3-pchelkin@ispras.ru> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230315202112.163012-1-pchelkin@ispras.ru> References: <20230315202112.163012-1-pchelkin@ispras.ru> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, the synchronization between ath9k_wmi_cmd() and ath9k_wmi_ctrl_rx() is exposed to races which can result, for example, not only in wmi->cmd_rsp_buf being incorrectly initialized, but in overall invalid behaviour of ath9k_wmi_cmd(). Consider the following scenario: CPU0 CPU1 ath9k_wmi_cmd(...) mutex_lock(&wmi->op_mutex) ath9k_wmi_cmd_issue(...) wait_for_completion_timeout(...) --- timeout --- mutex_unlock(&wmi->op_mutex) return -ETIMEDOUT ath9k_wmi_cmd(...) mutex_lock(&wmi->op_mutex) ath9k_wmi_cmd_issue(...) wait_for_completion_timeout(...) /* the one left after the first * ath9k_wmi_cmd call */ ath9k_wmi_rsp_callback(...) memcpy(...) complete(&wmi->cmd_wait); /* Awakened by the bogus callback * => invalid return */ mutex_unlock(&wmi->op_mutex) return 0 This may occur even on uniprocessor machines, and in SMP case the races may be even more intricate. To fix this, move the contents of ath9k_wmi_rsp_callback() under wmi_lock inside ath9k_wmi_ctrl_rx() so that the wmi->cmd_wait can be completed only for initially designated wmi_cmd call, otherwise the path would be rejected with last_seq_id check. Also move recording the rsp buffer and length into ath9k_wmi_cmd_issue() under the same wmi_lock with last_seq_id update to avoid their racy changes. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.") Reported-and-tested-by: syzbot+df61b36319e045c00a08@syzkaller.appspotmail.com Signed-off-by: Fedor Pchelkin --- This patch depends on [PATCH 1/3] wifi: ath9k: avoid referencing uninit memory in ath9k_wmi_ctrl_rx drivers/net/wireless/ath/ath9k/wmi.c | 48 ++++++++++++++-------------- 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c index 2e7c361b62f5..99a91bbaace9 100644 --- a/drivers/net/wireless/ath/ath9k/wmi.c +++ b/drivers/net/wireless/ath/ath9k/wmi.c @@ -200,20 +200,6 @@ void ath9k_fatal_work(struct work_struct *work) ath9k_htc_reset(priv); } -static void ath9k_wmi_rsp_callback(struct wmi *wmi, struct sk_buff *skb) -{ - skb_pull(skb, sizeof(struct wmi_cmd_hdr)); - - /* Once again validate the SKB. */ - if (unlikely(skb->len < wmi->cmd_rsp_len)) - return; - - if (wmi->cmd_rsp_buf != NULL && wmi->cmd_rsp_len != 0) - memcpy(wmi->cmd_rsp_buf, skb->data, wmi->cmd_rsp_len); - - complete(&wmi->cmd_wait); -} - static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb, enum htc_endpoint_id epid) { @@ -242,14 +228,26 @@ static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb, /* Check if there has been a timeout. */ spin_lock_irqsave(&wmi->wmi_lock, flags); - if (be16_to_cpu(hdr->seq_no) != wmi->last_seq_id) { + if (be16_to_cpu(hdr->seq_no) != wmi->last_seq_id || + be16_to_cpu(hdr->seq_no) == 0) { + spin_unlock_irqrestore(&wmi->wmi_lock, flags); + goto free_skb; + } + + /* Next, process WMI command response */ + skb_pull(skb, sizeof(struct wmi_cmd_hdr)); + + /* Once again validate the SKB. */ + if (unlikely(skb->len < wmi->cmd_rsp_len)) { spin_unlock_irqrestore(&wmi->wmi_lock, flags); goto free_skb; } - spin_unlock_irqrestore(&wmi->wmi_lock, flags); - /* WMI command response */ - ath9k_wmi_rsp_callback(wmi, skb); + if (wmi->cmd_rsp_buf != NULL && wmi->cmd_rsp_len != 0) + memcpy(wmi->cmd_rsp_buf, skb->data, wmi->cmd_rsp_len); + + complete(&wmi->cmd_wait); + spin_unlock_irqrestore(&wmi->wmi_lock, flags); free_skb: kfree_skb(skb); @@ -287,7 +285,8 @@ int ath9k_wmi_connect(struct htc_target *htc, struct wmi *wmi, static int ath9k_wmi_cmd_issue(struct wmi *wmi, struct sk_buff *skb, - enum wmi_cmd_id cmd, u16 len) + enum wmi_cmd_id cmd, u16 len, + u8 *rsp_buf, u32 rsp_len) { struct wmi_cmd_hdr *hdr; unsigned long flags; @@ -297,6 +296,11 @@ static int ath9k_wmi_cmd_issue(struct wmi *wmi, hdr->seq_no = cpu_to_be16(++wmi->tx_seq_id); spin_lock_irqsave(&wmi->wmi_lock, flags); + + /* record the rsp buffer and length */ + wmi->cmd_rsp_buf = rsp_buf; + wmi->cmd_rsp_len = rsp_len; + wmi->last_seq_id = wmi->tx_seq_id; spin_unlock_irqrestore(&wmi->wmi_lock, flags); @@ -337,11 +341,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id, goto out; } - /* record the rsp buffer and length */ - wmi->cmd_rsp_buf = rsp_buf; - wmi->cmd_rsp_len = rsp_len; - - ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len); + ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len, rsp_buf, rsp_len); if (ret) goto out; -- 2.34.1