Messages in this thread Patch in this message | | | Date | Fri, 3 Nov 2023 01:07:23 +0100 | From | Andi Shyti <> | Subject | Re: [PATCH] drm/i915: Fix potential spectre vulnerability |
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Hi,
On Thu, Nov 02, 2023 at 11:32:43AM +0000, Tvrtko Ursulin wrote: > 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+
Is this a real fix? I don't mind adding it, though.
> > --- > > 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);
idx has been assigned earlier, can we make it one single assignment at the declaration?
Andi
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