smb: server: Clear sensitive stack and heap data in auth.c

Sensitive data like keys that are stored in stack-local arrays could be
leaked via the stack to the calling functions, or via the heap when using
only normal kfree() functions. There is no known vulnaribility for this
right now, but it's good security style to explicitly zeroize this
sensitive matieral as soon as possible to avoid that it could be exploited
together with other bugs later.

In calc_ntlmv2_hash(), the struct hmac_md5_ctx is normally cleared during
hmac_md5_final() already, but in case of errors, this function is skipped
and ctx is never zeroized, so add a memzero_explicit(&ctx, sizeof(ctx))
there to fix the problem.

In ksmbd_krb5_authenticate(), the ksmbd_spnego_authen_response contains
the session key in the payload. It's currently freed with plain kvfree().
Let's better use kvfree_sensitive() instead.

In generate_key(), the prfhash[] array is used to calculate the key,
but it's never cleared, so it leaks on the stack. Thus clear this with
a memzero_explicit(), too.

In ksmbd_crypt_message(), the sign[] and key[] arrays are leaked via
the stack, too. Make sure to clear them via memzero_explicit() at the
end.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions