Problem Description:
When building the iovec array for a received TLS 1.2 CBC record,
ktls_ocf_tls_cbc_decrypt() incremented the iovec index for every
mbuf in the chain, including mbufs that were skipped because they
contained only TLS header bytes. This left uninitialized entries
in the iovec array. The iovec array was allocated without zeroing.
Impact:
A remote TLS peer can cause the kernel to read from uninitialized
iovec entries during HMAC computation, resulting in a kernel panic.
The peer must be able to control TCP segmentation such that the
first mbuf of a CBC record contains only the 5-byte TLS record
header.