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* [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl
@ 2023-03-28  9:36 Min Li
  2023-03-28 13:08 ` Tvrtko Ursulin
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Min Li @ 2023-03-28  9:36 UTC (permalink / raw)
  To: jani.nikula
  Cc: joonas.lahtinen, rodrigo.vivi, tvrtko.ursulin, airlied, daniel,
	intel-gfx, dri-devel, linux-kernel

Userspace can guess the id value and try to race oa_config object creation
with config remove, resulting in a use-after-free if we dereference the
object after unlocking the metrics_lock.  For that reason, unlocking the
metrics_lock must be done after we are done dereferencing the object.

Signed-off-by: Min Li <lm0963hack@gmail.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 824a34ec0b83..93748ca2c5da 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -4634,13 +4634,13 @@ int i915_perf_add_config_ioctl(struct drm_device *dev, void *data,
 		err = oa_config->id;
 		goto sysfs_err;
 	}
-
-	mutex_unlock(&perf->metrics_lock);
+	id = oa_config->id;
 
 	drm_dbg(&perf->i915->drm,
 		"Added config %s id=%i\n", oa_config->uuid, oa_config->id);
+	mutex_unlock(&perf->metrics_lock);
 
-	return oa_config->id;
+	return id;
 
 sysfs_err:
 	mutex_unlock(&perf->metrics_lock);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2023-03-29  9:20 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-03-28  9:36 [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl Min Li
2023-03-28 13:08 ` Tvrtko Ursulin
2023-03-29  0:48   ` Umesh Nerlige Ramappa
2023-03-29  9:20     ` Tvrtko Ursulin
2023-03-28 20:57 ` [Intel-gfx] " Andi Shyti
2023-03-28 21:08 ` Andi Shyti

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