[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <2dd63b5b-cf60-9f28-55b3-35eab537dc9b@linux.intel.com>
Date: Tue, 27 Feb 2024 17:45:11 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Armin Wolf <W_Armin@....de>, Shyam-sundar.S-k@....com
cc: Hans de Goede <hdegoede@...hat.com>, platform-driver-x86@...r.kernel.org,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] platform/x86/amd/pmf: Fix possible out-of-bound
memory accesses
Hi Shyam & Armin,
Shyam, please take a look at the question below.
On Tue, 27 Feb 2024, Armin Wolf wrote:
> The length of the policy buffer is not validated before accessing it,
> which means that multiple out-of-bounds memory accesses can occur.
>
> This is especially bad since userspace can load policy binaries over
> debugfs.
> + if (dev->policy_sz < POLICY_COOKIE_LEN + sizeof(length))
> + return -EINVAL;
> +
> cookie = *(u32 *)(dev->policy_buf + POLICY_COOKIE_OFFSET);
> length = *(u32 *)(dev->policy_buf + POLICY_COOKIE_LEN);
This starts to feel like adding a struct for the header(?) would be better
course of action here as then one could compare against sizeof(*header)
and avoid all those casts (IMO, just access the header fields directly
w/o the local variables).
Shyam, do you think a struct makes sense here? There's some header in
this policy, right?
There are more thing to address here...
1) amd_pmf_start_policy_engine() function returns -EINVAL & res that is
TA_PMF_* which inconsistent in type of the return value
2) Once 1) is fixed, the caller shadowing the return code can be fixed as
well:
ret = amd_pmf_start_policy_engine(dev);
if (ret)
return -EINVAL;
--
i.
Powered by blists - more mailing lists