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* [PATCH] drm/i915/fbdev: Hide smem_start from userspace
@ 2019-11-13 17:19 ` Chris Wilson
  0 siblings, 0 replies; 12+ messages in thread
From: Chris Wilson @ 2019-11-13 17:19 UTC (permalink / raw)
  To: intel-gfx; +Cc: Daniel Vetter

Do not leak our internal kernel address for random userspace to abuse.
Daniel added the support to fbdev to filter out the physical addresses
being exposed by fbdev, put that to use to protect ourselves.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112256
Fixes: 5f889b9a61dd ("drm/i915: Disregard drm_mode_config.fb_base")
References: da6c7707caf3 ("fbdev: Add FBINFO_HIDE_SMEM_START flag")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_fbdev.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
index 3d1061470e76..bff311561597 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -226,8 +226,8 @@ static int intelfb_create(struct drm_fb_helper *helper,
 		goto out_unpin;
 	}
 
-	ifbdev->helper.fb = &ifbdev->fb->base;
-
+	/* don't leak any physical addresses to userspace */
+	info->flags |= FBINFO_HIDE_SMEM_START;
 	info->fbops = &intelfb_ops;
 
 	/* setup aperture base/size for vesafb takeover */
@@ -247,6 +247,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	info->fix.smem_start = (unsigned long)info->screen_base;
 	info->fix.smem_len = info->screen_size;
 
+	ifbdev->helper.fb = &ifbdev->fb->base;
 	drm_fb_helper_fill_info(info, &ifbdev->helper, sizes);
 
 	/* If the object is shmemfs backed, it will have given us zeroed pages.
-- 
2.24.0

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^ permalink raw reply related	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2019-11-14 10:57 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2019-11-13 17:19 [PATCH] drm/i915/fbdev: Hide smem_start from userspace Chris Wilson
2019-11-13 17:19 ` [Intel-gfx] " Chris Wilson
2019-11-13 17:45 ` ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2019-11-13 17:45   ` [Intel-gfx] " Patchwork
2019-11-13 18:22 ` ✓ Fi.CI.BAT: success " Patchwork
2019-11-13 18:22   ` [Intel-gfx] " Patchwork
2019-11-14  9:42 ` ✓ Fi.CI.IGT: " Patchwork
2019-11-14  9:42   ` [Intel-gfx] " Patchwork
2019-11-14 10:53 ` [PATCH] " Ville Syrjälä
2019-11-14 10:53   ` [Intel-gfx] " Ville Syrjälä
2019-11-14 10:57   ` Chris Wilson
2019-11-14 10:57     ` [Intel-gfx] " Chris Wilson

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