[PATCH] KEYS: encrypted: fix key instantiation with user-provided data

[Mimi Zohar]

On Fri, 2022-09-16 at 07:45 +0200, Nikolaus Voss wrote:
> Commit cd3bc044af48 ("KEYS: encrypted: Instantiate key with user-provided
> decrypted data") added key instantiation with user provided decrypted data.
> The user data is hex-ascii-encoded but was just memcpy'ed to the binary buffer.
> Fix this to use hex2bin instead.

Thanks, Nikolaus.  We iterated a number of times over what would be the
safest userspace input.  One of the last changes was that the key data
should be hex-ascii-encoded.  Unfortunately, the LTP
testcases/kernel/syscalls/keyctl09.c example isn't hex-ascii-encoded
and the example in Documentation/security/keys/trusted-encrypted.rst
just cat's a file.  Both expect the length to be the length of the
userspace provided data.   With this patch, when hex2bin() fails, there
is no explanation.

-- 
thanks,

Mimi