From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F06EE30FA7 for ; Wed, 20 Sep 2023 12:27:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78527C433C8; Wed, 20 Sep 2023 12:27:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695212874; bh=sHwbw8IFwSghtugr5cyVqrOqByT5swEwDwKC76yEK9Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xUVMBWlVD5P+LI17H3HBCeymUJnmY3+3LQDQAowNg1ua9uaoX6gBWVSzFKxbfNU0v h1+H+8/a/phUJG7nfkHKE0FEn9K2u7LMR8m1WIxqXnRCbID3MZQQEYzSpnveKMV9DQ husLoj1RV4qB7eHJMIX0pvx4lpd9ZwGwy8ZgSJds= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fedor Pchelkin , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Kalle Valo , Sasha Levin Subject: [PATCH 5.4 078/367] wifi: ath9k: fix races between ath9k_wmi_cmd and ath9k_wmi_ctrl_rx Date: Wed, 20 Sep 2023 13:27:35 +0200 Message-ID: <20230920112900.556222009@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112858.471730572@linuxfoundation.org> References: <20230920112858.471730572@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fedor Pchelkin [ Upstream commit b674fb513e2e7a514fcde287c0f73915d393fdb6 ] Currently, the synchronization between ath9k_wmi_cmd() and ath9k_wmi_ctrl_rx() is exposed to a race condition which, although being rather unlikely, can lead to 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 --- /* the callback is being processed * before last_seq_id became zero */ ath9k_wmi_ctrl_rx(...) spin_lock_irqsave(...) /* wmi->last_seq_id check here * doesn't detect timeout yet */ spin_unlock_irqrestore(...) /* last_seq_id is zeroed to * indicate there was a timeout */ wmi->last_seq_id = 0 mutex_unlock(&wmi->op_mutex) return -ETIMEDOUT ath9k_wmi_cmd(...) mutex_lock(&wmi->op_mutex) /* the buffer is replaced with * another one */ wmi->cmd_rsp_buf = rsp_buf wmi->cmd_rsp_len = rsp_len ath9k_wmi_cmd_issue(...) spin_lock_irqsave(...) spin_unlock_irqrestore(...) wait_for_completion_timeout(...) /* the continuation of the * callback left after the first * ath9k_wmi_cmd call */ ath9k_wmi_rsp_callback(...) /* copying data designated * to already timeouted * WMI command into an * inappropriate wmi_cmd_buf */ memcpy(...) complete(&wmi->cmd_wait) /* awakened by the bogus callback * => invalid return result */ mutex_unlock(&wmi->op_mutex) return 0 To fix this, update last_seq_id on timeout path inside ath9k_wmi_cmd() under the wmi_lock. Move 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. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.") Signed-off-by: Fedor Pchelkin Acked-by: Toke Høiland-Jørgensen Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20230425192607.18015-1-pchelkin@ispras.ru Signed-off-by: Sasha Levin --- drivers/net/wireless/ath/ath9k/wmi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c index ef861b19fd477..96482ad23145c 100644 --- a/drivers/net/wireless/ath/ath9k/wmi.c +++ b/drivers/net/wireless/ath/ath9k/wmi.c @@ -239,10 +239,10 @@ static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb, 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); + spin_unlock_irqrestore(&wmi->wmi_lock, flags); free_skb: kfree_skb(skb); @@ -305,8 +305,8 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id, struct ath_common *common = ath9k_hw_common(ah); u16 headroom = sizeof(struct htc_frame_hdr) + sizeof(struct wmi_cmd_hdr); + unsigned long time_left, flags; struct sk_buff *skb; - unsigned long time_left; int ret = 0; if (ah->ah_flags & AH_UNPLUGGED) @@ -342,7 +342,9 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id, if (!time_left) { ath_dbg(common, WMI, "Timeout waiting for WMI command: %s\n", wmi_cmd_to_name(cmd_id)); + spin_lock_irqsave(&wmi->wmi_lock, flags); wmi->last_seq_id = 0; + spin_unlock_irqrestore(&wmi->wmi_lock, flags); mutex_unlock(&wmi->op_mutex); return -ETIMEDOUT; } -- 2.40.1