audit-ptrace patch (untested)

[Stephen Smalley]

On Tue, 2007-03-06 at 22:13 -0500, Alexander Viro wrote:
> OK...  Here's combined patch (with switch to security_task_getsecid(), etc.)

> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 3599558..f8875cb 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -729,6 +732,7 @@ static inline void audit_free_context(struct audit_context *context)
>  		audit_free_names(context);
>  		audit_free_aux(context);
>  		kfree(context->filterkey);
> +		kfree(context->obj_ctx);

Technically, this should be:
	 security_release_secctx(context->obj_ctx, context->ctxlen);
Although that does require keeping the length around, and the rest of
the audit code is already assuming it is just a string (unlike the
original user of these LSM hooks, the labeled IPSEC code).

> @@ -739,28 +743,26 @@ static inline void audit_free_context(struct audit_context *context)
>  void audit_log_task_context(struct audit_buffer *ab)
>  {
>  	char *ctx = NULL;
> -	ssize_t len = 0;
> +	unsigned len;
> +	int error;
> +	u32 sid;
>  
> -	len = security_getprocattr(current, "current", NULL, 0);
> -	if (len < 0) {
> -		if (len != -EINVAL)
> +	security_task_getsecid(current, &sid);
> +	if (!sid)
> +		return;
> +
> +	error = security_secid_to_secctx(sid, &ctx, &len);
> +	if (error) {
> +		if (error != -EINVAL)
>  			goto error_path;
>  		return;
>  	}
>  
> -	ctx = kmalloc(len, GFP_KERNEL);
> -	if (!ctx)
> -		goto error_path;
> -
> -	len = security_getprocattr(current, "current", ctx, len);
> -	if (len < 0 )
> -		goto error_path;
> -
>  	audit_log_format(ab, " subj=%s", ctx);
> +	kfree(ctx);

As above, technically should be:
	 security_release_secctx(ctx,len).

> @@ -1195,6 +1207,9 @@ void audit_syscall_exit(int valid, long return_code)
>  	} else {
>  		audit_free_names(context);
>  		audit_free_aux(context);
> +		kfree(context->obj_ctx);

And again.

Otherwise, looks fine.

-- 
Stephen Smalley
National Security Agency