From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E0EC86FBB for ; Tue, 10 Jan 2023 18:32:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C448C433D2; Tue, 10 Jan 2023 18:32:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673375524; bh=C0QGxNGzypsXuB2ieAt69FcxXPFpclzfYsbQgmcvwTo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J0NhV/jdsuH2GgtXs6UHZVf9IMpGQ2rjArVCJ2DWf1RGpoB9ArLjQ1BFpaA+awlLT hp4z26WRth6xM7QGxgnseC6sV1x+sq+b9WvuhJninEAS3CbHX2VswmeqLKVz0Ut2lW k+VkDa429t1pPZmrlrSNRwFTqiIrD1CnuUPp7WnA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Rob Clark , Steven Price , Rob Clark , Sasha Levin Subject: [PATCH 5.15 200/290] drm/panfrost: Fix GEM handle creation ref-counting Date: Tue, 10 Jan 2023 19:04:52 +0100 Message-Id: <20230110180038.865121024@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230110180031.620810905@linuxfoundation.org> References: <20230110180031.620810905@linuxfoundation.org> User-Agent: quilt/0.67 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 From: Steven Price [ Upstream commit 4217c6ac817451d5116687f3cc6286220dc43d49 ] panfrost_gem_create_with_handle() previously returned a BO but with the only reference being from the handle, which user space could in theory guess and release, causing a use-after-free. Additionally if the call to panfrost_gem_mapping_get() in panfrost_ioctl_create_bo() failed then a(nother) reference on the BO was dropped. The _create_with_handle() is a problematic pattern, so ditch it and instead create the handle in panfrost_ioctl_create_bo(). If the call to panfrost_gem_mapping_get() fails then this means that user space has indeed gone behind our back and freed the handle. In which case just return an error code. Reported-by: Rob Clark Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver") Signed-off-by: Steven Price Reviewed-by: Rob Clark Link: https://patchwork.freedesktop.org/patch/msgid/20221219140130.410578-1-steven.price@arm.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/panfrost/panfrost_drv.c | 27 ++++++++++++++++--------- drivers/gpu/drm/panfrost/panfrost_gem.c | 16 +-------------- drivers/gpu/drm/panfrost/panfrost_gem.h | 5 +---- 3 files changed, 20 insertions(+), 28 deletions(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index e48e357ea4f1..4c271244092b 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -82,6 +82,7 @@ static int panfrost_ioctl_create_bo(struct drm_device *dev, void *data, struct panfrost_gem_object *bo; struct drm_panfrost_create_bo *args = data; struct panfrost_gem_mapping *mapping; + int ret; if (!args->size || args->pad || (args->flags & ~(PANFROST_BO_NOEXEC | PANFROST_BO_HEAP))) @@ -92,21 +93,29 @@ static int panfrost_ioctl_create_bo(struct drm_device *dev, void *data, !(args->flags & PANFROST_BO_NOEXEC)) return -EINVAL; - bo = panfrost_gem_create_with_handle(file, dev, args->size, args->flags, - &args->handle); + bo = panfrost_gem_create(dev, args->size, args->flags); if (IS_ERR(bo)) return PTR_ERR(bo); + ret = drm_gem_handle_create(file, &bo->base.base, &args->handle); + if (ret) + goto out; + mapping = panfrost_gem_mapping_get(bo, priv); - if (!mapping) { - drm_gem_object_put(&bo->base.base); - return -EINVAL; + if (mapping) { + args->offset = mapping->mmnode.start << PAGE_SHIFT; + panfrost_gem_mapping_put(mapping); + } else { + /* This can only happen if the handle from + * drm_gem_handle_create() has already been guessed and freed + * by user space + */ + ret = -EINVAL; } - args->offset = mapping->mmnode.start << PAGE_SHIFT; - panfrost_gem_mapping_put(mapping); - - return 0; +out: + drm_gem_object_put(&bo->base.base); + return ret; } /** diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index 6d9bdb9180cb..55e3a68ed28a 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -234,12 +234,8 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t } struct panfrost_gem_object * -panfrost_gem_create_with_handle(struct drm_file *file_priv, - struct drm_device *dev, size_t size, - u32 flags, - uint32_t *handle) +panfrost_gem_create(struct drm_device *dev, size_t size, u32 flags) { - int ret; struct drm_gem_shmem_object *shmem; struct panfrost_gem_object *bo; @@ -255,16 +251,6 @@ panfrost_gem_create_with_handle(struct drm_file *file_priv, bo->noexec = !!(flags & PANFROST_BO_NOEXEC); bo->is_heap = !!(flags & PANFROST_BO_HEAP); - /* - * Allocate an id of idr table where the obj is registered - * and handle has the id what user can see. - */ - ret = drm_gem_handle_create(file_priv, &shmem->base, handle); - /* drop reference from allocate - handle holds it now. */ - drm_gem_object_put(&shmem->base); - if (ret) - return ERR_PTR(ret); - return bo; } diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index 8088d5fd8480..ad2877eeeccd 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -69,10 +69,7 @@ panfrost_gem_prime_import_sg_table(struct drm_device *dev, struct sg_table *sgt); struct panfrost_gem_object * -panfrost_gem_create_with_handle(struct drm_file *file_priv, - struct drm_device *dev, size_t size, - u32 flags, - uint32_t *handle); +panfrost_gem_create(struct drm_device *dev, size_t size, u32 flags); int panfrost_gem_open(struct drm_gem_object *obj, struct drm_file *file_priv); void panfrost_gem_close(struct drm_gem_object *obj, -- 2.35.1