Messages in this thread | | | Date | Thu, 2 Nov 2023 11:32:43 +0000 | Subject | Re: [PATCH] drm/i915: Fix potential spectre vulnerability | From | Tvrtko Ursulin <> |
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On 02/11/2023 10:16, chentao wrote: > Fix smatch warning: > drivers/gpu/drm/i915/gem/i915_gem_context.c:847 set_proto_ctx_sseu() > warn: potential spectre issue 'pc->user_engines' [r] (local cap) > > Signed-off-by: chentao <chentao@kylinos.cn>
I don't know if this is actually exploitable given the time deltas between the index is read from userspace and acted upon here, which is at least two ioctls apart. But I suppose no harm in fixing and for safety so we need to add:
Fixes: d4433c7600f7 ("drm/i915/gem: Use the proto-context to handle create parameters (v5)") Cc: <stable@vger.kernel.org> # v5.15+
> --- > drivers/gpu/drm/i915/gem/i915_gem_context.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c > index 9a9ff84c90d7..b2fdfc7ca4de 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c > @@ -843,7 +843,7 @@ static int set_proto_ctx_sseu(struct drm_i915_file_private *fpriv, > > if (idx >= pc->num_user_engines) > return -EINVAL; > -
Just please refrain from random whitespace modifications like this blank line removal. If you resend without that you can add my r-b.
Regards,
Tvrtko
> + idx = array_index_nospec(idx, pc->num_user_engines); > pe = &pc->user_engines[idx]; > > /* Only render engine supports RPCS configuration. */
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