Re: [PATCH] sysctl: ctl_table->parent is only used for sysctl checks

[ebiederm@xmission.com (Eric W. Biederman)]

Lucian Adrian Grijincu <lucian.grijincu@gmail.com> writes:

See selinux_sysctl_get_sid.

> Signed-off-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
> ---
>  include/linux/sysctl.h |    2 ++
>  kernel/sysctl.c        |    7 +++++--
>  2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index 7bb5cb6..026681f 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -1018,7 +1018,9 @@ struct ctl_table
>  	int maxlen;
>  	mode_t mode;
>  	struct ctl_table *child;
> +#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
>  	struct ctl_table *parent;	/* Automatically set */
> +#endif
>  	proc_handler *proc_handler;	/* Callback for text formatting */
>  	void *extra1;
>  	void *extra2;
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index ae5cbb1..c5bade1 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1706,6 +1706,7 @@ int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
>  	return test_perm(mode, op);
>  }
>  
> +#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
>  static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
>  {
>  	for (; table->procname; table++) {
> @@ -1714,11 +1715,13 @@ static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
>  			sysctl_set_parent(table, table->child);
>  	}
>  }
> +#endif
> +
>  
>  static __init int sysctl_init(void)
>  {
> -	sysctl_set_parent(NULL, root_table);
>  #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
> +	sysctl_set_parent(NULL, root_table);
>  	sysctl_check_table(current->nsproxy, root_table);
>  #endif
>  	return 0;
> @@ -1875,9 +1878,9 @@ struct ctl_table_header *__register_sysctl_paths(
>  	header->used = 0;
>  	header->unregistering = NULL;
>  	header->root = root;
> -	sysctl_set_parent(NULL, header->ctl_table);
>  	header->count = 1;
>  #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
> +	sysctl_set_parent(NULL, header->ctl_table);
>  	if (sysctl_check_table(namespaces, header->ctl_table)) {
>  		kfree(header);
>  		return NULL;