Messages in this thread | | | Date | Tue, 28 Mar 2023 14:08:47 +0100 | Subject | Re: [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl | From | Tvrtko Ursulin <> |
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On 28/03/2023 10:36, Min Li wrote: > 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>
Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG interface") Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com> Cc: <stable@vger.kernel.org> # v4.14+
> --- > 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);
LGTM.
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Umesh or Lionel could you please double check? I can merge if confirmed okay.
Regards,
Tvrtko
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