Re: [Intel-gfx] [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl
On Tue, Mar 28, 2023 at 05:36:27PM +0800, 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
I think we should also add
Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG
interface")
Cc: # v4.14+
Andi
> ---
> 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(>metrics_lock);
> + id = oa_config->id;
>
> drm_dbg(>i915->drm,
> "Added config %s id=%i\n", oa_config->uuid, oa_config->id);
> + mutex_unlock(>metrics_lock);
>
> - return oa_config->id;
> + return id;
>
> sysfs_err:
> mutex_unlock(>metrics_lock);
> --
> 2.25.1
Re: [Intel-gfx] [PATCH 1/1] drm/i915: fix race condition UAF in i915_perf_add_config_ioctl
Hi Min, On Tue, Mar 28, 2023 at 05:36:27PM +0800, 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 Thank you for your patch! Reviewed-by: Andi Shyti Andi > --- > 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(>metrics_lock); > + id = oa_config->id; > > drm_dbg(>i915->drm, > "Added config %s id=%i\n", oa_config->uuid, oa_config->id); > + mutex_unlock(>metrics_lock); > > - return oa_config->id; > + return id; > > sysfs_err: > mutex_unlock(>metrics_lock); > -- > 2.25.1
