From patchwork Wed Jul 3 13:31:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emil Velikov X-Patchwork-Id: 11029637 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6FB2D1398 for ; Wed, 3 Jul 2019 13:31:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5F8CB28972 for ; Wed, 3 Jul 2019 13:31:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 539292897E; Wed, 3 Jul 2019 13:31:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id EF87C28896 for ; Wed, 3 Jul 2019 13:31:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0F9CF6E13C; Wed, 3 Jul 2019 13:30:58 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4D7266E136; Wed, 3 Jul 2019 13:30:56 +0000 (UTC) Received: by mail-wr1-x442.google.com with SMTP id f9so2809244wre.12; Wed, 03 Jul 2019 06:30:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=vHMMy111qCPVlhn20MByNml0Hvj0MXblkspr7lTOdj8=; b=bYBk8L1YB93ahOCvEgPUNCoGrCbku+df3TBeaVKfwPqT4u/2VEJVzkvZE8IKqJyutn LlWDDFiixoKWNAhUpnqwNPNJemEib/UsB4F1UDca7f3ysfLFh6o6LRRovXIjTEhUrwTD 1sjSCLc0j8EKq0m3jdocwf+bbatG1HnNMWNnUjh0n3QpRUv+jhinA5OLHlpjwC/OaC9I iBIg0kJlZLWrHrUkmZu4vZfk+o0hNJWxQihZ033zmIRz5/zksxCmyh0EBP1NFqXXGCts bPgEY+X3uzUAstQIzVQvI5mGGmdvIyVVbWS/3DqwK6a1TzXShQzjAYeoaXaBbS8s+RBk F+Cw== X-Gm-Message-State: APjAAAViVcljn3SYYmjq/venaxJCJXF5GYxjHdoELW42MSc/FRtd7OnW npDWnJQG7KM1WwZ3xicgr87HjkH4 X-Google-Smtp-Source: APXvYqz6AL75fN06b2j9keUaa1qnKkC2xXkH+juMeyYkFLUSy0vvNNuLIj/PBzXyAS3TnrzLdfRxJA== X-Received: by 2002:adf:fdc2:: with SMTP id i2mr28767972wrs.146.1562160654616; Wed, 03 Jul 2019 06:30:54 -0700 (PDT) Received: from arch-x1c3.cbg.collabora.co.uk ([2a00:5f00:102:0:9665:9cff:feee:aa4d]) by smtp.gmail.com with ESMTPSA id g10sm2353263wrw.60.2019.07.03.06.30.53 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 03 Jul 2019 06:30:53 -0700 (PDT) From: Emil Velikov To: dri-devel@lists.freedesktop.org Date: Wed, 3 Jul 2019 14:31:04 +0100 Message-Id: <20190703133104.3211-3-emil.l.velikov@gmail.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190703133104.3211-1-emil.l.velikov@gmail.com> References: <20190703133104.3211-1-emil.l.velikov@gmail.com> MIME-Version: 1.0 X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vHMMy111qCPVlhn20MByNml0Hvj0MXblkspr7lTOdj8=; b=JkHrjsuehFsn3lKf3QZrZO8bxCjhwTtTS5jTJq9+Nzt/+c2HCGCp6azV8R2c8LRFzK zn1agcm0ncX2wiQKDky/xx3zTTbWyL51/KXcXX/7eKWfZhZLeQ+xYgM/+9GQLMLIpSRO bgwepc6n/Zv4H8nTAhKWNhzGu+jFt+YLrDLQH3ebrZa/ocfFxUpHH6zt/+0ktf/psNoI CTkjP8BvGQ9iJVZZc/hiBjzvxtzxjjkIcGuKcql4ryXgbcc3c33D/KlX4YeqV5yhQGDm F6aiOZp+jeHQoCdMme8kOKezFNLbLIcgvHGpysBno7uTEtgfxnfSZvMGSsLIATVGGqY8 Hi8A== Subject: [Intel-gfx] [PATCH 3/3] drm: allow render capable master with DRM_AUTH ioctls X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP From: Emil Velikov There are cases (in mesa and applications) where one would open the primary node without properly authenticating the client. Sometimes we don't check if the authentication succeeds, but there's also cases we simply forget to do it. The former was a case for Mesa where it did not not check the return value of drmGetMagic() [1]. That was fixed recently although, there's the question of older drivers or other apps that exbibit this behaviour. While omitting the call results in issues as seen in [2] and [3]. In the libva case, libva itself doesn't authenticate the DRM client and the vaGetDisplayDRM documentation doesn't mention if the app should either. As of today, the official vainfo utility doesn't authenticate. To workaround issues like these, some users resort to running their apps under sudo. Which admittedly isn't always a good idea. Since any DRIVER_RENDER driver has sufficient isolation between clients, we can use that, for unauthenticated [primary node] ioctls that require DRM_AUTH. But only if the respective ioctl is tagged as DRM_RENDER_ALLOW. v2: - Rework/simplify if check (Daniel V) - Add examples to commit messages, elaborate. (Daniel V) v3: - Use single unlikely (Daniel V) v4: - Reapply patch, use DRIVER_FORCE_AUTH w/a for amdgpu/radeon. [1] https://gitlab.freedesktop.org/mesa/mesa/blob/2bc1f5c2e70fe3b4d41f060af9859bc2a94c5b62/src/egl/drivers/dri2/platform_wayland.c#L1136 [2] https://lists.freedesktop.org/archives/libva/2016-July/004185.html [3] https://gitlab.freedesktop.org/mesa/kmscube/issues/1 Testcase: igt/core_unauth_vs_render Cc: intel-gfx@lists.freedesktop.org Cc: Daniel Vetter Signed-off-by: Emil Velikov Reviewed-by: Daniel Vetter --- drivers/gpu/drm/drm_ioctl.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 09f7f8e33fa3..c30feb5e97e3 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -517,6 +517,13 @@ int drm_version(struct drm_device *dev, void *data, return err; } +static inline bool +drm_render_driver_and_ioctl(const struct drm_device *dev, u32 flags) +{ + return drm_core_check_feature(dev, DRIVER_RENDER) && + (flags & DRM_RENDER_ALLOW); +} + /** * drm_ioctl_permit - Check ioctl permissions against caller * @@ -531,6 +538,8 @@ int drm_version(struct drm_device *dev, void *data, */ int drm_ioctl_permit(u32 flags, struct drm_file *file_priv) { + const struct drm_device *dev = file_priv->minor->dev; + /* ROOT_ONLY is only for CAP_SYS_ADMIN */ if (unlikely((flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN))) return -EACCES; @@ -538,7 +547,14 @@ int drm_ioctl_permit(u32 flags, struct drm_file *file_priv) /* AUTH is only for authenticated or render client */ if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) && !file_priv->authenticated)) - return -EACCES; + /* + * Although we allow: + * - render drivers with DRM_RENDER_ALLOW ioctls, when + * - drivers do not explicitly mandate authentication. + */ + if (!drm_render_driver_and_ioctl(dev, flags) || + drm_core_check_feature(dev, DRIVER_FORCE_AUTH)) + return -EACCES; /* MASTER is only for master or control clients */ if (unlikely((flags & DRM_MASTER) &&