From 49f6f6483b652108bcb73accd0204a464b922395 Mon Sep 17 00:00:00 2001 From: Min Li Date: Tue, 28 Mar 2023 17:36:27 +0800 Subject: [PATCH] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl 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 Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG interface") Cc: # v4.14+ Reviewed-by: Andi Shyti Reviewed-by: Umesh Nerlige Ramappa Signed-off-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20230328093627.5067-1-lm0963hack@gmail.com [tursulin: Manually added stable tag.] --- 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 c035dbb..050b8ae 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -4802,13 +4802,13 @@ 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); -- 2.7.4