From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 22E65338921 for ; Thu, 27 Nov 2025 16:02:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764259342; cv=none; b=sVGbg5esgs39LhI/18ObC5aSVByUNaLrlgG9q9Rgy1JPDyqlD4lTdwCorM2zpVYvZyRdaECSLpRVFj1pUprVDdSACAjfw/sg0otjCGEe9pYPbuw3W9Sau/UhstwNxqUWpTa/CSSlSpeI8vqov/j5H230SG+5lytHse0bBkokpbM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764259342; c=relaxed/simple; bh=zBZDnD8laiLPLIHMukqvj5wUArFQzn44pTlKaLD5KYQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pgJ1GWnsSAuG4N12Z/1PiNze4GDls9V3M5/bKh7dkdkFa69/LGHUrnFgk/YUX65pdSoTDM3ce1bbvmABBgjXHN32B4T/z0iqmrazjgC01XLiIOEqB8iZrivNOlOSZt+95PeyJ8I1sZEP/WetIcBq2I93TCWG0k7P0jcjY5YSxxQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DAF27176A; Thu, 27 Nov 2025 08:02:12 -0800 (PST) Received: from [10.1.31.95] (unknown [10.1.31.95]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CF2983F73B; Thu, 27 Nov 2025 08:02:17 -0800 (PST) Message-ID: Date: Thu, 27 Nov 2025 16:02:15 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/panthor: Prevent potential UAF in group creation To: Akash Goel , boris.brezillon@collabora.com, liviu.dudau@arm.com Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch, nd@arm.com References: <20251127081239.3744766-1-akash.goel@arm.com> From: Steven Price Content-Language: en-GB In-Reply-To: <20251127081239.3744766-1-akash.goel@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 27/11/2025 08:12, Akash Goel wrote: > This commit prevents the possibility of a use after free issue in the > GROUP_CREATE ioctl function, which arose as pointer to the group is > accessed in that ioctl function after storing it in the Xarray. > A malicious userspace can second guess the handle of a group and try > to call GROUP_DESTROY ioctl from another thread around the same time > as GROUP_CREATE ioctl. > > To prevent the use after free exploit, this commit uses a mark on an > entry of group pool Xarray which is added just before returning from > the GROUP_CREATE ioctl function. The mark is checked for all ioctls > that specify the group handle and so userspace won't be abe to delete > a group that isn't marked yet. > > Co-developed-by: Boris Brezillon > Signed-off-by: Akash Goel Reviewed-by: Steven Price I *think* this should have a... Fixes: d2624d90a0b7 ("drm/panthor: assign unique names to queues") ... as I don't believe it was a problem before the rearrangement that happened there. Thanks, Steve > --- > drivers/gpu/drm/panthor/panthor_sched.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c > index b834123a6560..a6b8024e1a3c 100644 > --- a/drivers/gpu/drm/panthor/panthor_sched.c > +++ b/drivers/gpu/drm/panthor/panthor_sched.c > @@ -779,6 +779,12 @@ struct panthor_job_profiling_data { > */ > #define MAX_GROUPS_PER_POOL 128 > > +/* > + * Mark added on an entry of group pool Xarray to identify if the group has > + * been fully initialized and can be accessed elsewhere in the driver code. > + */ > +#define GROUP_REGISTERED XA_MARK_1 > + > /** > * struct panthor_group_pool - Group pool > * > @@ -3007,7 +3013,7 @@ void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) > return; > > xa_lock(&gpool->xa); > - xa_for_each(&gpool->xa, i, group) { > + xa_for_each_marked(&gpool->xa, i, group, GROUP_REGISTERED) { > guard(spinlock)(&group->fdinfo.lock); > pfile->stats.cycles += group->fdinfo.data.cycles; > pfile->stats.time += group->fdinfo.data.time; > @@ -3727,6 +3733,8 @@ int panthor_group_create(struct panthor_file *pfile, > > group_init_task_info(group); > > + xa_set_mark(&gpool->xa, gid, GROUP_REGISTERED); > + > return gid; > > err_erase_gid: > @@ -3744,6 +3752,9 @@ int panthor_group_destroy(struct panthor_file *pfile, u32 group_handle) > struct panthor_scheduler *sched = ptdev->scheduler; > struct panthor_group *group; > > + if (!xa_get_mark(&gpool->xa, group_handle, GROUP_REGISTERED)) > + return -EINVAL; > + > group = xa_erase(&gpool->xa, group_handle); > if (!group) > return -EINVAL; > @@ -3769,12 +3780,12 @@ int panthor_group_destroy(struct panthor_file *pfile, u32 group_handle) > } > > static struct panthor_group *group_from_handle(struct panthor_group_pool *pool, > - u32 group_handle) > + unsigned long group_handle) > { > struct panthor_group *group; > > xa_lock(&pool->xa); > - group = group_get(xa_load(&pool->xa, group_handle)); > + group = group_get(xa_find(&pool->xa, &group_handle, group_handle, GROUP_REGISTERED)); > xa_unlock(&pool->xa); > > return group; > @@ -3861,7 +3872,7 @@ panthor_fdinfo_gather_group_mem_info(struct panthor_file *pfile, > return; > > xa_lock(&gpool->xa); > - xa_for_each(&gpool->xa, i, group) { > + xa_for_each_marked(&gpool->xa, i, group, GROUP_REGISTERED) { > stats->resident += group->fdinfo.kbo_sizes; > if (group->csg_id >= 0) > stats->active += group->fdinfo.kbo_sizes;