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 074273C5525; Wed, 29 Jul 2026 09:19:54 +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=1785316796; cv=none; b=HoHyYF1RtPaT3po3VUZP0KFi5hSeFUDsqhI17uisT9yXzi4KmUhdxGwHXhxai8yoqpEE3IOVLbZM1rLjj72tNV0Es/uiT9QDkxH61dnarCJ2v6LSIQQKMwjLnwpH0/y3Yg23sEa8HwptVNqZrOUCmtQQ/C36iVUL3wDzkP2KRIs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785316796; c=relaxed/simple; bh=nqwd1aeayF/tTSe1p1DlzBVqmH9ArOQHbigtgzdusZc=; h=From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type:Date; b=qKnF6iC1YRsA2rhFzIbTehFxb0Sy7Q/3J2/EpSpFMv5gwYinN54fkiBss3Ur6yLXG0SmIZgQVkI2GNidhCrWNHkTWcExejFDsN70hvKbV7A5yZqt+DJ6lK1nuQt58nsfAY5rTWt0T4BVyBL22uswrUcbT8IdjN3TKNnuiQDLdrs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=obGo9WYI; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="obGo9WYI" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 6577E1F000E9; Wed, 29 Jul 2026 09:19:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785316794; bh=79VI3Ct6agLLEKvEp8Q1IlyWfRd7S13KEiFjfSd6Ndw=; h=From:To:Cc:Subject:Date; b=obGo9WYIxUw0p4y8Ly0PTrWD433q065h8b8YT6X5BHQPOAGV5RXP7xsrGgvPM03vB WNiJ28mkYMVDjvlboVEZePdETp+hmIuJ59mAmt527p9Y4Z+38gL8mx/tVGO9W7ojty Qet/mM0Tf2jyGc8agX8/YJAlfOHiCe/hHYGDt3L8Uq0vWP/RdDYb7YH62SwPADEwIt nQRoB55UfDsAL2EQ3kxCT3kYsVefp4zbuD0ELOwfnTRbYruG+E3QTySPT4bqpLceAq YdwfYlAbWcX4pRMEWbk5VUGHNirhipfWyci36Z/NYmNXXeBJPEoXzsZowcXFyOEoYf j/9UNv2W//+Sw== From: "syzbot" To: syzkaller-bugs@googlegroups.com, Aleksandr Nogikh , "Greg Kroah-Hartman" , , "Greg Kroah-Hartman" Cc: kees@kernel.org, linux-kernel@vger.kernel.org, syzbot@lists.linux.dev Subject: [PATCH] usb: usbtest: fix NULL pointer dereference in usbtest_probe Message-ID: <2650cf0f-26f9-48b5-b198-e4cb67c59cf0@mail.kernel.org> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Date: Wed, 29 Jul 2026 09:19:54 +0000 (UTC) From: Aleksandr Nogikh The usbtest driver relies on the driver_info field of the usb_device_id structure to hold a pointer to a struct usbtest_info, which contains necessary configuration for the device. When a new device ID is dynamically added via the sysfs new_id interface without specifying a reference device, the driver_info field defaults to 0. When the USB core binds the device using this dynamic ID, usbtest_probe() unconditionally casts the 0 to a pointer, resulting in a NULL pointer dereference when attempting to access the autoconf bitfield (at offset 0xa) of the struct usbtest_info. This leads to the following crash: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:usbtest_probe+0x522/0xcc0 drivers/usb/misc/usbtest.c:2822 Call Trace: usb_probe_interface+0x653/0xc60 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500 __device_attach+0x2c4/0x450 drivers/base/dd.c:1098 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153 bus_probe_device+0x12a/0x220 drivers/base/bus.c:620 device_add+0x7d7/0xb80 drivers/base/core.c:3772 usb_set_configuration+0x1ad8/0x2180 drivers/usb/core/message.c:2268 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250 usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:291 To fix this, validate that id->driver_info is not NULL before proceeding with the probe. If it is NULL, gracefully return -ENODEV. The check is placed before any memory allocation to avoid unnecessary work and simplify error handling. Fixes: 733260ff9c45 ("[PATCH] USB: add dynamic id functionality to USB core") Assisted-by: Gemini:gemini-3.5-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+7e1e5911f9eac50bedc7@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7e1e5911f9eac50bedc7 Link: https://syzkaller.appspot.com/ai_job?id=9e476ca5-99d1-47d2-b9d1-f3b501897179 Signed-off-by: Aleksandr Nogikh --- diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c index 98071b25a..6410b3e26 100644 --- a/drivers/usb/misc/usbtest.c +++ b/drivers/usb/misc/usbtest.c @@ -2786,10 +2786,13 @@ usbtest_probe(struct usb_interface *intf, const struct usb_device_id *id) } #endif + info = (struct usbtest_info *) id->driver_info; + if (!info) + return -ENODEV; + dev = kzalloc_obj(*dev); if (!dev) return -ENOMEM; - info = (struct usbtest_info *) id->driver_info; dev->info = info; mutex_init(&dev->lock); base-commit: f5098b6bae761e346ebcd9da7f95622c04733cff -- See https://goo.gle/syzbot-ai-patches for information about AI-generated patches. You can comment on the patch as usual, syzbot will try to address the comments and send a new version of the patch if necessary. syzbot engineers can be reached at syzkaller@googlegroups.com.