From patchwork Mon Dec 11 15:32:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 13487414 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="bHOc7iw1" Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09AC5E3 for ; Mon, 11 Dec 2023 07:33:11 -0800 (PST) Received: by mail-pg1-x52f.google.com with SMTP id 41be03b00d2f7-5c68da9d639so2586877a12.3 for ; Mon, 11 Dec 2023 07:33:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1702308790; x=1702913590; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=u9nyIKtamCpicw2WPRHA84FcbnZ7MvQb17dWhMR1seM=; b=bHOc7iw1f4LInPU0QY/OUI5mmSiPL9kHRlaIduOgjj64lFRxdRmMH3bCzmKG2qpTS+ jcg99u6XCshn+QB6m/gKVtGCLws1aYJKdq26J0SgtYK5Q2bSPGLnqos6P2Q6XQYENYwB 57KZA6CfkPopVR7wkD0qLH1LSTscBL6xIYqeo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702308790; x=1702913590; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=u9nyIKtamCpicw2WPRHA84FcbnZ7MvQb17dWhMR1seM=; b=FW+aTagcc8cz1s8T2d8xrBCsEfLNM9/VHHEn5gBHwwLATbLIX0TDLDWDzLOQhyIjwC gt+wVUYjgO2zEyuwD+gXjlbmKAWOdqnUdxpYN82Ja8eLk8pGiWEsLLdooiFD3GsQAnyC gYCPhjMFdqw6djkacxeVR7gUjHqrQVBMmY6oEsHeL7XebRU0RpaCCsgolkccdg7n7FVA Ns8QqGdvSI3S3slSojH3wVXi1SpAvtXYQ/QfTX4/TLkHasehV1Psn5HsNne5pIrd2asC o5FCF8GlTxhqU+pDNXSyXqGELVtorkvxizP7eKyQId7XbNX+1nIwM3g/tJsyWAEMF3AJ OoRg== X-Gm-Message-State: AOJu0Yz4jB+L35jOiGVoYv6GLvv55rIVoha1G+W+S1rTbWhEF8aVdB/c m5Gda2zMTuUgXKXixgyrEwzqz16gb8vn/t7uaK8= X-Google-Smtp-Source: AGHT+IEJ82IJ2l2KnYVTDw2r7IaBgHAFat5OWA0r+Y0uPDs92zOArKh4IAJKuOYTNG1KJWot5LRlFQ== X-Received: by 2002:a05:6a20:8f08:b0:18c:3260:e20f with SMTP id b8-20020a056a208f0800b0018c3260e20fmr2612497pzk.33.1702308789981; Mon, 11 Dec 2023 07:33:09 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:5c08:e1ed:d922:d30c]) by smtp.gmail.com with ESMTPSA id x1-20020a63cc01000000b005742092c211sm6299572pgf.64.2023.12.11.07.33.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 07:33:09 -0800 (PST) From: Douglas Anderson To: linux-usb@vger.kernel.org, Greg Kroah-Hartman Cc: Eric Dumazet , netdev@vger.kernel.org, "David S . Miller" , Simon Horman , Jakub Kicinski , Hayes Wang , =?utf-8?q?Bj=C3=B8rn_Mork?= , Paolo Abeni , Brian Geffon , Grant Grundler , Alan Stern , Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v3] usb: core: Fix crash w/ usb_choose_configuration() if no driver Date: Mon, 11 Dec 2023 07:32:41 -0800 Message-ID: <20231211073237.v3.1.If27eb3bf7812f91ab83810f232292f032f4203e0@changeid> X-Mailer: git-send-email 2.43.0.472.g3155946c3a-goog Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 It's possible that usb_choose_configuration() can get called when a USB device has no driver. In this case the recent commit a87b8e3be926 ("usb: core: Allow subclassed USB drivers to override usb_choose_configuration()") can cause a crash since it dereferenced the driver structure without checking for NULL. Let's add a check. A USB device with no driver is an anomaly, so make usb_choose_configuration() return immediately if there is no driver. This was seen in the real world when usbguard got ahold of a r8152 device at the wrong time. It can also be simulated via this on a computer with one r8152-based USB Ethernet adapter: cd /sys/bus/usb/drivers/r8152-cfgselector to_unbind="$(ls -d *-*)" real_dir="$(readlink -f "${to_unbind}")" echo "${to_unbind}" > unbind cd "${real_dir}" echo 0 > authorized echo 1 > authorized Fixes: a87b8e3be926 ("usb: core: Allow subclassed USB drivers to override usb_choose_configuration()") Reviewed-by: Alan Stern Signed-off-by: Douglas Anderson --- Changes in v3: - Add comment in code, as per Alan. Changes in v2: - Return immediately if no driver, as per Alan. drivers/usb/core/generic.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index dcb897158228..b134bff5c3fe 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -59,7 +59,16 @@ int usb_choose_configuration(struct usb_device *udev) int num_configs; int insufficient_power = 0; struct usb_host_config *c, *best; - struct usb_device_driver *udriver = to_usb_device_driver(udev->dev.driver); + struct usb_device_driver *udriver; + + /* + * If a USB device (not an interface) doesn't have a driver then the + * kernel has no business trying to select or install a configuration + * for it. + */ + if (!udev->dev.driver) + return -1; + udriver = to_usb_device_driver(udev->dev.driver); if (usb_device_is_owned(udev)) return 0;