audit: remove audit_finish_fork as it can't be called

Audit entry,always rules are not allowed and are automatically changed in
exit,always rules in userspace.  The kernel refuses to load such rules.

Thus a task in the middle of a syscall (and thus in audit_finish_fork())
can only be in one of two states: AUDIT_BUILD_CONTEXT or AUDIT_DISABLED.
Since the current task cannot be in AUDIT_RECORD_CONTEXT we aren't every
going to actually use the code in audit_finish_fork() since it will
return without doing anything.  Thus drop the code.
Signed-off-by: NEric Paris <eparis@redhat.com>

include/linux/audit.h

@@ -415,7 +415,6 @@ extern int audit_classify_arch(int arch);
 #ifdef CONFIG_AUDITSYSCALL
 /* These are defined in auditsc.c */
 				/* Public API */
-extern void audit_finish_fork(struct task_struct *child);
 extern int  audit_alloc(struct task_struct *task);
 extern void __audit_free(struct task_struct *task);
 extern void __audit_syscall_entry(int arch,
@@ -586,7 +585,6 @@ static inline void audit_mmap_fd(int fd, int flags)
 extern int audit_n_rules;
 extern int audit_signals;
 #else /* CONFIG_AUDITSYSCALL */
-#define audit_finish_fork(t)
 #define audit_alloc(t) ({ 0; })
 #define audit_free(t) do { ; } while (0)
 #define audit_syscall_entry(ta,a,b,c,d,e) do { ; } while (0)

kernel/auditsc.c

@@ -1707,26 +1707,6 @@ void __audit_syscall_entry(int arch, int major,
 	context->ppid       = 0;
 }
 
-void audit_finish_fork(struct task_struct *child)
-{
-	struct audit_context *ctx = current->audit_context;
-	struct audit_context *p = child->audit_context;
-	if (!p || !ctx)
-		return;
-	if (!ctx->in_syscall || ctx->current_state != AUDIT_RECORD_CONTEXT)
-		return;
-	p->arch = ctx->arch;
-	p->major = ctx->major;
-	memcpy(p->argv, ctx->argv, sizeof(ctx->argv));
-	p->ctime = ctx->ctime;
-	p->dummy = ctx->dummy;
-	p->in_syscall = ctx->in_syscall;
-	p->filterkey = kstrdup(ctx->filterkey, GFP_KERNEL);
-	p->ppid = current->pid;
-	p->prio = ctx->prio;
-	p->current_state = ctx->current_state;
-}
-
 /**
  * audit_syscall_exit - deallocate audit context after a system call
  * @pt_regs: syscall registers

kernel/fork.c

@@ -1525,8 +1525,6 @@ long do_fork(unsigned long clone_flags,
 			init_completion(&vfork);
 		}
 
-		audit_finish_fork(p);
-
 		/*
 		 * We set PF_STARTING at creation in case tracing wants to
 		 * use this to distinguish a fully live task from one that