From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 71353367B67; Thu, 30 Jul 2026 15:03:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423794; cv=none; b=FUhM6RhykfQ52GCk+BSlv1FDMTilr/iM7hPgrlW2slF9Q0SVJPVJh4SxDDgtbeNrydOt8qB0NwR3o1zni9w0s7rIzP3/6uU8hPX2dFWK1om2uHZPEfs1HhT8YOGCpBIriDfcTZdYgK8kTS9+/3kakuiuKwG3Ye33JFRMKohGIPU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423794; c=relaxed/simple; bh=FyouKX7iBs2ObkORfI6392RXvTOb/kH2pM3th/ZjTWM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LVnIVKjTEA9AQ4LbGxj0QwTlb8J1fQ/zEtghu44uIGdQYhLOI9NlyY2ivErvg/yIRBRoBf9x2XsgXp/VoL2ZKzLPROqfvInDHLt2AgSpqiWe81jdXXugOtFJ2dpFrFhMBekjsvOqihgnc1YjDX1GqlXHToVxBdgyl2miNoa0+IY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sJI/wsS6; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="sJI/wsS6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC3DE1F000E9; Thu, 30 Jul 2026 15:03:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785423793; bh=DNc/YUJMDaOnHA4DDfkpQVdUK5y6Syyg8lFt23FsZxk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sJI/wsS6HYPRlmRG7oQCOw5fLe9M6Y58gv/tf/zfX7gd4qOO5y8aGRIGKq7NRfl6S vf3nsY/JKI5YtfAR/XeykqT8F/mNc4RklV863DRN2C4LlKM7JUhp129XodSG72YwhL efNMeAEcI1HZ6FMosvcweIsFBg6IAIe9q8s0V2no= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+50122cbc2874b1eb25b0@syzkaller.appspotmail.com, Cheng Yongkang , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Jeff Johnson , Sasha Levin Subject: [PATCH 6.18 166/675] wifi: ath9k: hif_usb: dont dereference hif_dev after re-arming firmware request Date: Thu, 30 Jul 2026 16:08:16 +0200 Message-ID: <20260730141448.665780948@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141445.110192266@linuxfoundation.org> References: <20260730141445.110192266@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cheng Yongkang [ Upstream commit dad9f96945d77ecd4708f730c06ef54dcd8cc057 ] ath9k_hif_request_firmware() re-arms an asynchronous firmware load via request_firmware_nowait(), passing hif_dev as the completion context, and then still dereferences hif_dev: dev_info(&hif_dev->udev->dev, "ath9k_htc: Firmware %s requested\n", hif_dev->fw_name); The re-armed callback ath9k_hif_usb_firmware_cb() runs on the "events" workqueue and, when the firmware is missing, walks the retry chain into ath9k_hif_usb_firmware_fail() -> complete_all(&hif_dev->fw_done). That releases the wait_for_completion(&hif_dev->fw_done) in a concurrent ath9k_hif_usb_disconnect(), which then kfree()s hif_dev. The trailing dev_info() in the frame that re-armed the request can therefore read freed memory (hif_dev->udev, the first field of struct hif_device_usb): BUG: KASAN: slab-use-after-free in ath9k_hif_request_firmware Read of size 8 ... by task kworker/... ath9k_hif_request_firmware ath9k_hif_usb_firmware_cb drivers/net/wireless/ath/ath9k/hif_usb.c:1247 request_firmware_work_func Allocated by ...: ath9k_hif_usb_probe drivers/net/wireless/ath/ath9k/hif_usb.c Freed by ...: ath9k_hif_usb_disconnect -> kfree drivers/net/wireless/ath/ath9k/hif_usb.c The fw_done barrier only makes disconnect wait for the firmware chain to *terminate*; it does not protect the outer ath9k_hif_request_firmware() frame that re-armed the request and keeps touching hif_dev afterwards. Drop the post-request dev_info(): it is the only use of hif_dev after the async request is armed, and it is purely informational (the dev_err() on the failure path runs only when request_firmware_nowait() did not arm a callback, so hif_dev is still alive there). This was first reported by syzbot as a single, non-reproduced crash that was later auto-obsoleted, and was independently rediscovered by the reFuzz fuzzer, which produced a C reproducer (USB-gadget connect/disconnect of an ath9k_htc device whose firmware download fails). The vulnerable code is unchanged and still present in v7.1-rc6, where the slab-use-after-free reproduces under KASAN once the (sub-microsecond) race window is widened. Fixes: e904cf6fe230 ("ath9k_htc: introduce support for different fw versions") Reported-by: syzbot+50122cbc2874b1eb25b0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=50122cbc2874b1eb25b0 Signed-off-by: Cheng Yongkang Acked-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260605153210.20471-1-1020691186@qq.com Signed-off-by: Jeff Johnson Signed-off-by: Sasha Levin --- drivers/net/wireless/ath/ath9k/hif_usb.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c index fe9abe8cd268fa..0a3d2190b9beec 100644 --- a/drivers/net/wireless/ath/ath9k/hif_usb.c +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c @@ -1225,15 +1225,10 @@ static int ath9k_hif_request_firmware(struct hif_device_usb *hif_dev, ret = request_firmware_nowait(THIS_MODULE, true, hif_dev->fw_name, &hif_dev->udev->dev, GFP_KERNEL, hif_dev, ath9k_hif_usb_firmware_cb); - if (ret) { + if (ret) dev_err(&hif_dev->udev->dev, "ath9k_htc: Async request for firmware %s failed\n", hif_dev->fw_name); - return ret; - } - - dev_info(&hif_dev->udev->dev, "ath9k_htc: Firmware %s requested\n", - hif_dev->fw_name); return ret; } -- 2.53.0