crypto: seqiv - Do not use req->iv after crypto_aead_encrypt

In the Linux kernel, the following vulnerability has been resolved:

crypto: seqiv - Do not use req->iv after crypto_aead_encrypt

As soon as crypto_aead_encrypt is called, the underlying request may be freed by an asynchronous completion. Thus dereferencing req->iv after it returns is invalid.

Instead of checking req->iv against info, create a new variable unaligned_info and use it for that purpose instead.