lsm: Only build lsm_audit.c if CONFIG_SECURITY and CONFIG_AUDIT are set

When CONFIG_AUDIT is set, its CONFIG_NET dependency is also set, and the
dev_get_by_index and init_net symbols (used by dump_common_audit_data)
are found by the linker.  dump_common_audit_data() should then failed to
build when CONFIG_NET is not set. However, because the compiler is
smart, it knows that audit_log_start() always return NULL when
!CONFIG_AUDIT, and it doesn't build the body of common_lsm_audit().  As
a side effect, dump_common_audit_data() is not built and the linker
doesn't error out because of missing symbols.

Let's only build lsm_audit.o when CONFIG_SECURITY and CONFIG_AUDIT are
both set, which is checked with the new CONFIG_HAS_SECURITY_AUDIT.

ipv4_skb_to_auditdata() and ipv6_skb_to_auditdata() are only used by
Smack if CONFIG_AUDIT is set, so they don't need fake implementations.

Because common_lsm_audit() is used in multiple places without
CONFIG_AUDIT checks, add a fake implementation.

Link: https://lore.kernel.org/r/[email protected]
Cc: Casey Schaufler <[email protected]>
Cc: James Morris <[email protected]>
Cc: Paul Moore <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Signed-off-by: Mickaël Salaün <[email protected]>
Signed-off-by: Paul Moore <[email protected]>

0 files changed, 0 insertions, 0 deletions