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.
