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 2033933EB10 for ; Thu, 6 Aug 2026 13:45:24 +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=1786023926; cv=none; b=U6buh8WEH/iSSVqjD7TYhXxmgZNS+pjFTLFsFW/xfTzEKK5MbH3FEBGK0OXun52SA2XGO80L8QNZAYnsq8H7/kR2KrgQ/N0efDDSSmFnyPMYo0wPVGz8yLTFu29rES3SI6YjaLqKkY/E0b0lXdjXcEHNa123sH2zxQjuKhY2E0k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786023926; c=relaxed/simple; bh=a0CpvkwT2s6F2hup0qicJlJ4qQofjTpMoqfs73vMbWY=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=kBk0cOi4doYwi7EsyXMWiZP/gRx/lzEGqGAMPK4r4sfIQC3BlYDN2AituRKn2FJyW6U/r1OQ6knwoJe0KJlncDIjvQY8y0MOU/EPk1e9dfWwlUIT0QfkTTwDG67K7XL+keudVpduDqOeaNcZD5pFqFxzLkHQ3dbP3LRTywrBp68= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VP/j/1WH; 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="VP/j/1WH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DEEC1F000E9; Thu, 6 Aug 2026 13:45:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786023924; bh=XpQMAhFQd/di1nMC72MRSNQf97ZENnjMrFdp0Rain/8=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=VP/j/1WH64ZIpWOtVXJ1k5z03Q0s10kcA1pA/WbwcDapLk1YBAaIMGG52tgj5D8Iw E/NMG0dwIuwsOTKz9HaW7QT0P7ZlIqYQVSliJ/A2K0WF2AbuWSdSvbXOgePArcgGGp N8xZiyCkT1wA/uqF6xrSGBZU5Z0eMmZg2N+fJatGbqE/I3cLKsvKTRr3UXROFZJEEp uhongZwjTscGEgZVmS7F8ZxnqcT4sfGvHoTpknDlXvY1jcxDNm5AQDjf8uDguIlz3r jpbmLXD5UaQNV2BxgBh2oRPfyRC8wNetu5RSB8b0gYO5P4klxeYO5mTxNw9hOwQmxG eud5jyVj9+EeQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH V4 07/14] i3c: master: Fix potential UAF in i3c_device_match() Reply-To: sashiko-reviews@lists.linux.dev To: "Adrian Hunter" Cc: linux-i3c@lists.infradead.org, "Alexandre Belloni" , linux-pci@vger.kernel.org, Frank.Li@kernel.org In-Reply-To: <20260806131857.119830-8-adrian.hunter@intel.com> References: <20260806131857.119830-1-adrian.hunter@intel.com> <20260806131857.119830-8-adrian.hunter@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 06 Aug 2026 13:45:23 +0000 Message-Id: <20260806134524.6DEEC1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 2 potential issue(= s) to consider: - [High] Removing the NULL check for `i3cdev->desc` introduces a determinis= tic NULL pointer dereference during device unregistration and registration = error paths. - [High] `i3c_device_get_info()` dereferences `dev->desc` without checking = for NULL under the lock, causing a NULL pointer dereference. -- --- Patch [7]: [PATCH V4 07/14] i3c: master: Fix potential UAF in i3c_devic= e_match() --- commit 4b5a3c82a1c4c5f9bf31e925977c2286520960fc Author: Adrian Hunter i3c: master: Fix potential UAF in i3c_device_match() This commit protects access to i3cdev->desc with the normal-use lock to prevent a use-after-free when the descriptor pointer is concurrently replaced. Since the descriptor is assumed to remain valid while the lock is held, the NULL check is removed. > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c > index ee771ac0b203e..83e04a2c202a9 100644 > --- a/drivers/i3c/master.c > +++ b/drivers/i3c/master.c > @@ -347,8 +347,10 @@ static int i3c_device_match(struct device *dev, cons= t struct device_driver *drv) > i3cdev =3D dev_to_i3cdev(dev); > i3cdrv =3D drv_to_i3cdrv(drv); > =20 > - if (i3cdev->desc && i3cdev->desc->boardinfo) > + i3c_bus_normaluse_lock(i3cdev->bus); > + if (i3cdev->desc->boardinfo) [Severity: High] Is it safe to remove the NULL check for i3cdev->desc here? If a userspace process writes to a driver's bind file via sysfs concurrently with a device registration failure, bind_store() will call driver_match_device() and eventually reach i3c_device_match(). In the error path of i3c_master_register_new_i3c_devs(), i3cdev->desc is set to NULL under the write lock. When this code subsequently acquires the read lock, i3cdev->desc will be NULL, which could cause a NULL pointer dereference. Similarly, i3c_master_unregister_i3c_devs() locklessly sets i3cdev->desc to NULL during teardown, which can also race with this path. > static_addr_method =3D i3cdev->desc->boardinfo->static_addr_method; > + i3c_bus_normaluse_unlock(i3cdev->bus); > =20 > /* > * SETAASA-based devices need not always have a matching ID since > * it is not mandatory for such devices to implement deviceinfo > * CCC commands. Allow them to register through DT or ACPI. > */ > if (i3cdrv->id_table && i3c_device_match_id(i3cdev, i3cdrv->id_table)) [Severity: High] Does this call to i3c_device_match_id() have a similar vulnerability? i3c_device_match_id() eventually calls i3c_device_get_info(). While i3c_device_get_info() does acquire the normal-use lock, it directly reads dev->desc->info without checking if dev->desc is valid. If a bind operation races with device unregistration or a registration error path, dev->desc could be set to NULL before the lock is acquired, leading to a crash when reading dev->desc->info. > return 1; > =20 > if (static_addr_method & I3C_ADDR_METHOD_SETAASA) { [ ... ] --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260806131857.1198= 30-1-adrian.hunter@intel.com?part=3D7