linux-kernel - [PATCH 5.1 001/155] Revert "drm: allow render capable master with DRM

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Message-Id: <20190613075652.777739182@linuxfoundation.org>
Date:   Thu, 13 Jun 2019 10:31:53 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dave Airlie <airlied@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.1 001/155] Revert "drm: allow render capable master with DRM_AUTH ioctls"

[ Upstream commit dbb92471674a48892f5e50779425e03388073ab9 ]

This reverts commit 8059add0478e29cb641936011a8fcc9ce9fd80be.

This commit while seemingly a good idea, breaks a radv check,
for a node being master because something succeeds where it failed
before now.

Apply the Linus rule, revert early and try again, we don't break
userspace.

Signed-off-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/drm_ioctl.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 687943df58e1..ab5692104ea0 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -508,13 +508,6 @@ 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
  *
@@ -529,19 +522,14 @@ drm_render_driver_and_ioctl(const struct drm_device *dev, u32 flags)
  */
 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;
 
-	/* AUTH is only for master ... */
-	if (unlikely((flags & DRM_AUTH) && drm_is_primary_client(file_priv))) {
-		/* authenticated ones, or render capable on DRM_RENDER_ALLOW. */
-		if (!file_priv->authenticated &&
-		    !drm_render_driver_and_ioctl(dev, flags))
-			return -EACCES;
-	}
+	/* AUTH is only for authenticated or render client */
+	if (unlikely((flags & DRM_AUTH) && !drm_is_render_client(file_priv) &&
+		     !file_priv->authenticated))
+		return -EACCES;
 
 	/* MASTER is only for master or control clients */
 	if (unlikely((flags & DRM_MASTER) &&
-- 
2.20.1