On 02.06.2018 21:12, Maciej S. Szmigiero wrote:

On 19.05.2018 14:23, Maciej S. Szmigiero wrote:

quoted

The signatureValue field of a X.509 certificate is encoded as a BIT STRING.
For RSA signatures this BIT STRING is of so-called primitive subtype, which
contains a u8 prefix indicating a count of unused bits in the encoding.

We have to strip this prefix from signature data, just as we already do for
key data in x509_extract_key_data() function.

This wasn't noticed earlier because this prefix byte is zero for RSA key
sizes divisible by 8. Since BIT STRING is a big-endian encoding adding zero
prefixes has no bearing on its value.

The signature length, however was incorrect, which is a problem for RSA
implementations that need it to be exactly correct (like AMD CCP).

Any progress here?
This simple patch has already been submitted 3 times in last 3+ months...

A friendly ping here.

@AMD people:
Without this patch, in-kernel X.509 certificate verification is broken
on AMD CCP RSA implementation.

For example, loading wireless regulatory database gives the following
errors:

[   21.310361] cfg80211: Problem loading in-kernel X.509 certificate (-22)
[   21.351717] cfg80211: loaded regulatory.db is malformed or signature is missing/invalid

Kernel modules signature verification probably has similar problem, too.

That's why it would be nice if you could ack this patch, please.

Maciej
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