Messages in this thread | | | Date | Tue, 28 Mar 2023 17:48:15 -0700 | From | Umesh Nerlige Ramappa <> | Subject | Re: [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl |
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On Tue, Mar 28, 2023 at 02:08:47PM +0100, Tvrtko Ursulin wrote: > >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.
LGTM,
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Thanks, Umesh
> >Regards, > >Tvrtko
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