RFC: AF_ALG auditing

Hello, attached is an user-space patch that adds support for auditing uses of the AF_ALG protocol family developed by Herbert Xu to provide user-space access to kernel crypto accelerators. Kernel patches will follow. One new record is defined: AUDIT_CRYPTO_USERSPACE_OP. An audited event is always caused by a syscall, and all other syscall-related data (process identity, syscall result) is audited in the usual records. To disable auditing crypto by default and to allow the users to selectively enable them using filters, a new filter field AUDIT_CRYPTO_OP is defined; auditing of all crypto operations can thus be enabled using (auditctl -a exit,always -F crypto_op!=0). In addition to the user-space patch, attached are also a few example audit entries. Mirek