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97324cd804
This adds a small helper retire_sysctl_set to remove the intimate knowledge about the how a sysctl_set is implemented from net/sysct_net.c Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
1099 lines
27 KiB
C
1099 lines
27 KiB
C
/*
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* /proc/sys support
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*/
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#include <linux/init.h>
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#include <linux/sysctl.h>
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#include <linux/poll.h>
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#include <linux/proc_fs.h>
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#include <linux/security.h>
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#include <linux/namei.h>
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#include <linux/module.h>
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#include "internal.h"
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static const struct dentry_operations proc_sys_dentry_operations;
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static const struct file_operations proc_sys_file_operations;
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static const struct inode_operations proc_sys_inode_operations;
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static const struct file_operations proc_sys_dir_file_operations;
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static const struct inode_operations proc_sys_dir_operations;
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void proc_sys_poll_notify(struct ctl_table_poll *poll)
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{
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if (!poll)
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return;
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atomic_inc(&poll->event);
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wake_up_interruptible(&poll->wait);
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}
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static struct ctl_table root_table[1];
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static struct ctl_table_root sysctl_table_root;
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static struct ctl_table_header root_table_header = {
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{{.count = 1,
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.ctl_table = root_table,
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.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
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.root = &sysctl_table_root,
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.set = &sysctl_table_root.default_set,
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};
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static struct ctl_table_root sysctl_table_root = {
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.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
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.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
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};
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static DEFINE_SPINLOCK(sysctl_lock);
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/* called under sysctl_lock */
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static int use_table(struct ctl_table_header *p)
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{
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if (unlikely(p->unregistering))
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return 0;
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p->used++;
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return 1;
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}
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/* called under sysctl_lock */
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static void unuse_table(struct ctl_table_header *p)
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{
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if (!--p->used)
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if (unlikely(p->unregistering))
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complete(p->unregistering);
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}
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/* called under sysctl_lock, will reacquire if has to wait */
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static void start_unregistering(struct ctl_table_header *p)
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{
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/*
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* if p->used is 0, nobody will ever touch that entry again;
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* we'll eliminate all paths to it before dropping sysctl_lock
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*/
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if (unlikely(p->used)) {
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struct completion wait;
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init_completion(&wait);
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p->unregistering = &wait;
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spin_unlock(&sysctl_lock);
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wait_for_completion(&wait);
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spin_lock(&sysctl_lock);
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} else {
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/* anything non-NULL; we'll never dereference it */
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p->unregistering = ERR_PTR(-EINVAL);
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}
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/*
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* do not remove from the list until nobody holds it; walking the
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* list in do_sysctl() relies on that.
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*/
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list_del_init(&p->ctl_entry);
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}
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static void sysctl_head_get(struct ctl_table_header *head)
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{
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spin_lock(&sysctl_lock);
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head->count++;
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spin_unlock(&sysctl_lock);
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}
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void sysctl_head_put(struct ctl_table_header *head)
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{
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spin_lock(&sysctl_lock);
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if (!--head->count)
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kfree_rcu(head, rcu);
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spin_unlock(&sysctl_lock);
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}
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static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
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{
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if (!head)
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BUG();
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spin_lock(&sysctl_lock);
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if (!use_table(head))
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head = ERR_PTR(-ENOENT);
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spin_unlock(&sysctl_lock);
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return head;
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}
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static void sysctl_head_finish(struct ctl_table_header *head)
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{
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if (!head)
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return;
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spin_lock(&sysctl_lock);
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unuse_table(head);
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spin_unlock(&sysctl_lock);
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}
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static struct ctl_table_set *
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lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
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{
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struct ctl_table_set *set = &root->default_set;
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if (root->lookup)
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set = root->lookup(root, namespaces);
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return set;
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}
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static struct list_head *
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lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
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{
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struct ctl_table_set *set = lookup_header_set(root, namespaces);
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return &set->list;
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}
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static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
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struct ctl_table_header *prev)
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{
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struct ctl_table_root *root;
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struct list_head *header_list;
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struct ctl_table_header *head;
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struct list_head *tmp;
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spin_lock(&sysctl_lock);
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if (prev) {
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head = prev;
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tmp = &prev->ctl_entry;
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unuse_table(prev);
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goto next;
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}
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tmp = &root_table_header.ctl_entry;
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for (;;) {
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head = list_entry(tmp, struct ctl_table_header, ctl_entry);
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if (!use_table(head))
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goto next;
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spin_unlock(&sysctl_lock);
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return head;
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next:
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root = head->root;
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tmp = tmp->next;
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header_list = lookup_header_list(root, namespaces);
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if (tmp != header_list)
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continue;
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do {
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root = list_entry(root->root_list.next,
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struct ctl_table_root, root_list);
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if (root == &sysctl_table_root)
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goto out;
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header_list = lookup_header_list(root, namespaces);
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} while (list_empty(header_list));
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tmp = header_list->next;
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}
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out:
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spin_unlock(&sysctl_lock);
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return NULL;
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}
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static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
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{
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return __sysctl_head_next(current->nsproxy, prev);
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}
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void register_sysctl_root(struct ctl_table_root *root)
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{
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spin_lock(&sysctl_lock);
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list_add_tail(&root->root_list, &sysctl_table_root.root_list);
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spin_unlock(&sysctl_lock);
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}
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/*
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* sysctl_perm does NOT grant the superuser all rights automatically, because
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* some sysctl variables are readonly even to root.
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*/
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static int test_perm(int mode, int op)
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{
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if (!current_euid())
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mode >>= 6;
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else if (in_egroup_p(0))
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mode >>= 3;
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if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
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return 0;
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return -EACCES;
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}
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static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
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{
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int mode;
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if (root->permissions)
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mode = root->permissions(root, current->nsproxy, table);
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else
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mode = table->mode;
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return test_perm(mode, op);
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}
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static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
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{
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for (; table->procname; table++) {
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table->parent = parent;
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if (table->child)
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sysctl_set_parent(table, table->child);
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}
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}
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static struct inode *proc_sys_make_inode(struct super_block *sb,
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struct ctl_table_header *head, struct ctl_table *table)
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{
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struct inode *inode;
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struct proc_inode *ei;
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inode = new_inode(sb);
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if (!inode)
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goto out;
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inode->i_ino = get_next_ino();
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sysctl_head_get(head);
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ei = PROC_I(inode);
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ei->sysctl = head;
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ei->sysctl_entry = table;
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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inode->i_mode = table->mode;
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if (!table->child) {
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inode->i_mode |= S_IFREG;
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inode->i_op = &proc_sys_inode_operations;
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inode->i_fop = &proc_sys_file_operations;
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} else {
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inode->i_mode |= S_IFDIR;
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inode->i_op = &proc_sys_dir_operations;
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inode->i_fop = &proc_sys_dir_file_operations;
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}
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out:
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return inode;
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}
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static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
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{
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for ( ; p->procname; p++) {
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if (strlen(p->procname) != name->len)
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continue;
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if (memcmp(p->procname, name->name, name->len) != 0)
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continue;
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/* I have a match */
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return p;
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}
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return NULL;
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}
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static struct ctl_table_header *grab_header(struct inode *inode)
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{
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if (PROC_I(inode)->sysctl)
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return sysctl_head_grab(PROC_I(inode)->sysctl);
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else
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return sysctl_head_next(NULL);
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}
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static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
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struct nameidata *nd)
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{
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struct ctl_table_header *head = grab_header(dir);
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struct ctl_table *table = PROC_I(dir)->sysctl_entry;
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struct ctl_table_header *h = NULL;
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struct qstr *name = &dentry->d_name;
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struct ctl_table *p;
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struct inode *inode;
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struct dentry *err = ERR_PTR(-ENOENT);
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if (IS_ERR(head))
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return ERR_CAST(head);
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if (table && !table->child) {
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WARN_ON(1);
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goto out;
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}
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table = table ? table->child : head->ctl_table;
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p = find_in_table(table, name);
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if (!p) {
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for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
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if (h->attached_to != table)
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continue;
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p = find_in_table(h->attached_by, name);
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if (p)
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break;
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}
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}
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if (!p)
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goto out;
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err = ERR_PTR(-ENOMEM);
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inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
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if (h)
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sysctl_head_finish(h);
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if (!inode)
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goto out;
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err = NULL;
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d_set_d_op(dentry, &proc_sys_dentry_operations);
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d_add(dentry, inode);
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out:
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sysctl_head_finish(head);
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return err;
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}
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static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
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size_t count, loff_t *ppos, int write)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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struct ctl_table_header *head = grab_header(inode);
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struct ctl_table *table = PROC_I(inode)->sysctl_entry;
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ssize_t error;
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size_t res;
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if (IS_ERR(head))
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return PTR_ERR(head);
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/*
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* At this point we know that the sysctl was not unregistered
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* and won't be until we finish.
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*/
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error = -EPERM;
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if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
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goto out;
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/* if that can happen at all, it should be -EINVAL, not -EISDIR */
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error = -EINVAL;
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if (!table->proc_handler)
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goto out;
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/* careful: calling conventions are nasty here */
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res = count;
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error = table->proc_handler(table, write, buf, &res, ppos);
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if (!error)
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error = res;
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out:
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sysctl_head_finish(head);
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return error;
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}
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static ssize_t proc_sys_read(struct file *filp, char __user *buf,
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size_t count, loff_t *ppos)
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{
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return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
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}
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static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
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}
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static int proc_sys_open(struct inode *inode, struct file *filp)
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{
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struct ctl_table *table = PROC_I(inode)->sysctl_entry;
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if (table->poll)
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filp->private_data = proc_sys_poll_event(table->poll);
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return 0;
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}
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static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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struct ctl_table *table = PROC_I(inode)->sysctl_entry;
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unsigned long event = (unsigned long)filp->private_data;
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unsigned int ret = DEFAULT_POLLMASK;
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if (!table->proc_handler)
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goto out;
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if (!table->poll)
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goto out;
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poll_wait(filp, &table->poll->wait, wait);
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if (event != atomic_read(&table->poll->event)) {
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filp->private_data = proc_sys_poll_event(table->poll);
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ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI;
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}
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out:
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return ret;
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}
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|
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static int proc_sys_fill_cache(struct file *filp, void *dirent,
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filldir_t filldir,
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struct ctl_table_header *head,
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struct ctl_table *table)
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{
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struct dentry *child, *dir = filp->f_path.dentry;
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struct inode *inode;
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struct qstr qname;
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ino_t ino = 0;
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unsigned type = DT_UNKNOWN;
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qname.name = table->procname;
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qname.len = strlen(table->procname);
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qname.hash = full_name_hash(qname.name, qname.len);
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child = d_lookup(dir, &qname);
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if (!child) {
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child = d_alloc(dir, &qname);
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if (child) {
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inode = proc_sys_make_inode(dir->d_sb, head, table);
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if (!inode) {
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dput(child);
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return -ENOMEM;
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} else {
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d_set_d_op(child, &proc_sys_dentry_operations);
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d_add(child, inode);
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}
|
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} else {
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return -ENOMEM;
|
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}
|
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}
|
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inode = child->d_inode;
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ino = inode->i_ino;
|
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type = inode->i_mode >> 12;
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dput(child);
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return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
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}
|
|
|
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static int scan(struct ctl_table_header *head, ctl_table *table,
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unsigned long *pos, struct file *file,
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void *dirent, filldir_t filldir)
|
|
{
|
|
|
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for (; table->procname; table++, (*pos)++) {
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int res;
|
|
|
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if (*pos < file->f_pos)
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continue;
|
|
|
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res = proc_sys_fill_cache(file, dirent, filldir, head, table);
|
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if (res)
|
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return res;
|
|
|
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file->f_pos = *pos + 1;
|
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}
|
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return 0;
|
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}
|
|
|
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static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
|
|
{
|
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struct dentry *dentry = filp->f_path.dentry;
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struct inode *inode = dentry->d_inode;
|
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struct ctl_table_header *head = grab_header(inode);
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struct ctl_table *table = PROC_I(inode)->sysctl_entry;
|
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struct ctl_table_header *h = NULL;
|
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unsigned long pos;
|
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int ret = -EINVAL;
|
|
|
|
if (IS_ERR(head))
|
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return PTR_ERR(head);
|
|
|
|
if (table && !table->child) {
|
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WARN_ON(1);
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|
goto out;
|
|
}
|
|
|
|
table = table ? table->child : head->ctl_table;
|
|
|
|
ret = 0;
|
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/* Avoid a switch here: arm builds fail with missing __cmpdi2 */
|
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if (filp->f_pos == 0) {
|
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if (filldir(dirent, ".", 1, filp->f_pos,
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inode->i_ino, DT_DIR) < 0)
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goto out;
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|
filp->f_pos++;
|
|
}
|
|
if (filp->f_pos == 1) {
|
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if (filldir(dirent, "..", 2, filp->f_pos,
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parent_ino(dentry), DT_DIR) < 0)
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goto out;
|
|
filp->f_pos++;
|
|
}
|
|
pos = 2;
|
|
|
|
ret = scan(head, table, &pos, filp, dirent, filldir);
|
|
if (ret)
|
|
goto out;
|
|
|
|
for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
|
|
if (h->attached_to != table)
|
|
continue;
|
|
ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
|
|
if (ret) {
|
|
sysctl_head_finish(h);
|
|
break;
|
|
}
|
|
}
|
|
ret = 1;
|
|
out:
|
|
sysctl_head_finish(head);
|
|
return ret;
|
|
}
|
|
|
|
static int proc_sys_permission(struct inode *inode, int mask)
|
|
{
|
|
/*
|
|
* sysctl entries that are not writeable,
|
|
* are _NOT_ writeable, capabilities or not.
|
|
*/
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *table;
|
|
int error;
|
|
|
|
/* Executable files are not allowed under /proc/sys/ */
|
|
if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
|
|
return -EACCES;
|
|
|
|
head = grab_header(inode);
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
table = PROC_I(inode)->sysctl_entry;
|
|
if (!table) /* global root - r-xr-xr-x */
|
|
error = mask & MAY_WRITE ? -EACCES : 0;
|
|
else /* Use the permissions on the sysctl table entry */
|
|
error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK);
|
|
|
|
sysctl_head_finish(head);
|
|
return error;
|
|
}
|
|
|
|
static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
|
|
if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
|
|
return -EPERM;
|
|
|
|
error = inode_change_ok(inode, attr);
|
|
if (error)
|
|
return error;
|
|
|
|
if ((attr->ia_valid & ATTR_SIZE) &&
|
|
attr->ia_size != i_size_read(inode)) {
|
|
error = vmtruncate(inode, attr->ia_size);
|
|
if (error)
|
|
return error;
|
|
}
|
|
|
|
setattr_copy(inode, attr);
|
|
mark_inode_dirty(inode);
|
|
return 0;
|
|
}
|
|
|
|
static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
struct ctl_table_header *head = grab_header(inode);
|
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
|
|
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
generic_fillattr(inode, stat);
|
|
if (table)
|
|
stat->mode = (stat->mode & S_IFMT) | table->mode;
|
|
|
|
sysctl_head_finish(head);
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations proc_sys_file_operations = {
|
|
.open = proc_sys_open,
|
|
.poll = proc_sys_poll,
|
|
.read = proc_sys_read,
|
|
.write = proc_sys_write,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
static const struct file_operations proc_sys_dir_file_operations = {
|
|
.read = generic_read_dir,
|
|
.readdir = proc_sys_readdir,
|
|
.llseek = generic_file_llseek,
|
|
};
|
|
|
|
static const struct inode_operations proc_sys_inode_operations = {
|
|
.permission = proc_sys_permission,
|
|
.setattr = proc_sys_setattr,
|
|
.getattr = proc_sys_getattr,
|
|
};
|
|
|
|
static const struct inode_operations proc_sys_dir_operations = {
|
|
.lookup = proc_sys_lookup,
|
|
.permission = proc_sys_permission,
|
|
.setattr = proc_sys_setattr,
|
|
.getattr = proc_sys_getattr,
|
|
};
|
|
|
|
static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
if (nd->flags & LOOKUP_RCU)
|
|
return -ECHILD;
|
|
return !PROC_I(dentry->d_inode)->sysctl->unregistering;
|
|
}
|
|
|
|
static int proc_sys_delete(const struct dentry *dentry)
|
|
{
|
|
return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
|
|
}
|
|
|
|
static int sysctl_is_seen(struct ctl_table_header *p)
|
|
{
|
|
struct ctl_table_set *set = p->set;
|
|
int res;
|
|
spin_lock(&sysctl_lock);
|
|
if (p->unregistering)
|
|
res = 0;
|
|
else if (!set->is_seen)
|
|
res = 1;
|
|
else
|
|
res = set->is_seen(set);
|
|
spin_unlock(&sysctl_lock);
|
|
return res;
|
|
}
|
|
|
|
static int proc_sys_compare(const struct dentry *parent,
|
|
const struct inode *pinode,
|
|
const struct dentry *dentry, const struct inode *inode,
|
|
unsigned int len, const char *str, const struct qstr *name)
|
|
{
|
|
struct ctl_table_header *head;
|
|
/* Although proc doesn't have negative dentries, rcu-walk means
|
|
* that inode here can be NULL */
|
|
/* AV: can it, indeed? */
|
|
if (!inode)
|
|
return 1;
|
|
if (name->len != len)
|
|
return 1;
|
|
if (memcmp(name->name, str, len))
|
|
return 1;
|
|
head = rcu_dereference(PROC_I(inode)->sysctl);
|
|
return !head || !sysctl_is_seen(head);
|
|
}
|
|
|
|
static const struct dentry_operations proc_sys_dentry_operations = {
|
|
.d_revalidate = proc_sys_revalidate,
|
|
.d_delete = proc_sys_delete,
|
|
.d_compare = proc_sys_compare,
|
|
};
|
|
|
|
static struct ctl_table *is_branch_in(struct ctl_table *branch,
|
|
struct ctl_table *table)
|
|
{
|
|
struct ctl_table *p;
|
|
const char *s = branch->procname;
|
|
|
|
/* branch should have named subdirectory as its first element */
|
|
if (!s || !branch->child)
|
|
return NULL;
|
|
|
|
/* ... and nothing else */
|
|
if (branch[1].procname)
|
|
return NULL;
|
|
|
|
/* table should contain subdirectory with the same name */
|
|
for (p = table; p->procname; p++) {
|
|
if (!p->child)
|
|
continue;
|
|
if (p->procname && strcmp(p->procname, s) == 0)
|
|
return p;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/* see if attaching q to p would be an improvement */
|
|
static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
|
|
{
|
|
struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
|
|
struct ctl_table *next;
|
|
int is_better = 0;
|
|
int not_in_parent = !p->attached_by;
|
|
|
|
while ((next = is_branch_in(by, to)) != NULL) {
|
|
if (by == q->attached_by)
|
|
is_better = 1;
|
|
if (to == p->attached_by)
|
|
not_in_parent = 1;
|
|
by = by->child;
|
|
to = next->child;
|
|
}
|
|
|
|
if (is_better && not_in_parent) {
|
|
q->attached_by = by;
|
|
q->attached_to = to;
|
|
q->parent = p;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
|
|
static int sysctl_depth(struct ctl_table *table)
|
|
{
|
|
struct ctl_table *tmp;
|
|
int depth;
|
|
|
|
depth = 0;
|
|
for (tmp = table; tmp->parent; tmp = tmp->parent)
|
|
depth++;
|
|
|
|
return depth;
|
|
}
|
|
|
|
static struct ctl_table *sysctl_parent(struct ctl_table *table, int n)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; table && i < n; i++)
|
|
table = table->parent;
|
|
|
|
return table;
|
|
}
|
|
|
|
|
|
static void sysctl_print_path(struct ctl_table *table)
|
|
{
|
|
struct ctl_table *tmp;
|
|
int depth, i;
|
|
depth = sysctl_depth(table);
|
|
if (table->procname) {
|
|
for (i = depth; i >= 0; i--) {
|
|
tmp = sysctl_parent(table, i);
|
|
printk("/%s", tmp->procname?tmp->procname:"");
|
|
}
|
|
}
|
|
printk(" ");
|
|
}
|
|
|
|
static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
|
|
struct ctl_table *table)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *ref, *test;
|
|
int depth, cur_depth;
|
|
|
|
depth = sysctl_depth(table);
|
|
|
|
for (head = __sysctl_head_next(namespaces, NULL); head;
|
|
head = __sysctl_head_next(namespaces, head)) {
|
|
cur_depth = depth;
|
|
ref = head->ctl_table;
|
|
repeat:
|
|
test = sysctl_parent(table, cur_depth);
|
|
for (; ref->procname; ref++) {
|
|
int match = 0;
|
|
if (cur_depth && !ref->child)
|
|
continue;
|
|
|
|
if (test->procname && ref->procname &&
|
|
(strcmp(test->procname, ref->procname) == 0))
|
|
match++;
|
|
|
|
if (match) {
|
|
if (cur_depth != 0) {
|
|
cur_depth--;
|
|
ref = ref->child;
|
|
goto repeat;
|
|
}
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
ref = NULL;
|
|
out:
|
|
sysctl_head_finish(head);
|
|
return ref;
|
|
}
|
|
|
|
static void set_fail(const char **fail, struct ctl_table *table, const char *str)
|
|
{
|
|
if (*fail) {
|
|
printk(KERN_ERR "sysctl table check failed: ");
|
|
sysctl_print_path(table);
|
|
printk(" %s\n", *fail);
|
|
dump_stack();
|
|
}
|
|
*fail = str;
|
|
}
|
|
|
|
static void sysctl_check_leaf(struct nsproxy *namespaces,
|
|
struct ctl_table *table, const char **fail)
|
|
{
|
|
struct ctl_table *ref;
|
|
|
|
ref = sysctl_check_lookup(namespaces, table);
|
|
if (ref && (ref != table))
|
|
set_fail(fail, table, "Sysctl already exists");
|
|
}
|
|
|
|
static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table)
|
|
{
|
|
int error = 0;
|
|
for (; table->procname; table++) {
|
|
const char *fail = NULL;
|
|
|
|
if (table->parent) {
|
|
if (!table->parent->procname)
|
|
set_fail(&fail, table, "Parent without procname");
|
|
}
|
|
if (table->child) {
|
|
if (table->data)
|
|
set_fail(&fail, table, "Directory with data?");
|
|
if (table->maxlen)
|
|
set_fail(&fail, table, "Directory with maxlen?");
|
|
if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode)
|
|
set_fail(&fail, table, "Writable sysctl directory");
|
|
if (table->proc_handler)
|
|
set_fail(&fail, table, "Directory with proc_handler");
|
|
if (table->extra1)
|
|
set_fail(&fail, table, "Directory with extra1");
|
|
if (table->extra2)
|
|
set_fail(&fail, table, "Directory with extra2");
|
|
} else {
|
|
if ((table->proc_handler == proc_dostring) ||
|
|
(table->proc_handler == proc_dointvec) ||
|
|
(table->proc_handler == proc_dointvec_minmax) ||
|
|
(table->proc_handler == proc_dointvec_jiffies) ||
|
|
(table->proc_handler == proc_dointvec_userhz_jiffies) ||
|
|
(table->proc_handler == proc_dointvec_ms_jiffies) ||
|
|
(table->proc_handler == proc_doulongvec_minmax) ||
|
|
(table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
|
|
if (!table->data)
|
|
set_fail(&fail, table, "No data");
|
|
if (!table->maxlen)
|
|
set_fail(&fail, table, "No maxlen");
|
|
}
|
|
#ifdef CONFIG_PROC_SYSCTL
|
|
if (!table->proc_handler)
|
|
set_fail(&fail, table, "No proc_handler");
|
|
#endif
|
|
sysctl_check_leaf(namespaces, table, &fail);
|
|
}
|
|
if (table->mode > 0777)
|
|
set_fail(&fail, table, "bogus .mode");
|
|
if (fail) {
|
|
set_fail(&fail, table, NULL);
|
|
error = -EINVAL;
|
|
}
|
|
if (table->child)
|
|
error |= sysctl_check_table(namespaces, table->child);
|
|
}
|
|
return error;
|
|
}
|
|
#endif /* CONFIG_SYSCTL_SYSCALL_CHECK */
|
|
|
|
/**
|
|
* __register_sysctl_paths - register a sysctl hierarchy
|
|
* @root: List of sysctl headers to register on
|
|
* @namespaces: Data to compute which lists of sysctl entries are visible
|
|
* @path: The path to the directory the sysctl table is in.
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* The members of the &struct ctl_table structure are used as follows:
|
|
*
|
|
* procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
|
|
* enter a sysctl file
|
|
*
|
|
* data - a pointer to data for use by proc_handler
|
|
*
|
|
* maxlen - the maximum size in bytes of the data
|
|
*
|
|
* mode - the file permissions for the /proc/sys file, and for sysctl(2)
|
|
*
|
|
* child - a pointer to the child sysctl table if this entry is a directory, or
|
|
* %NULL.
|
|
*
|
|
* proc_handler - the text handler routine (described below)
|
|
*
|
|
* de - for internal use by the sysctl routines
|
|
*
|
|
* extra1, extra2 - extra pointers usable by the proc handler routines
|
|
*
|
|
* Leaf nodes in the sysctl tree will be represented by a single file
|
|
* under /proc; non-leaf nodes will be represented by directories.
|
|
*
|
|
* sysctl(2) can automatically manage read and write requests through
|
|
* the sysctl table. The data and maxlen fields of the ctl_table
|
|
* struct enable minimal validation of the values being written to be
|
|
* performed, and the mode field allows minimal authentication.
|
|
*
|
|
* There must be a proc_handler routine for any terminal nodes
|
|
* mirrored under /proc/sys (non-terminals are handled by a built-in
|
|
* directory handler). Several default handlers are available to
|
|
* cover common cases -
|
|
*
|
|
* proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
|
|
* proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
|
|
* proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
|
|
*
|
|
* It is the handler's job to read the input buffer from user memory
|
|
* and process it. The handler should return 0 on success.
|
|
*
|
|
* This routine returns %NULL on a failure to register, and a pointer
|
|
* to the table header on success.
|
|
*/
|
|
struct ctl_table_header *__register_sysctl_paths(
|
|
struct ctl_table_root *root,
|
|
struct nsproxy *namespaces,
|
|
const struct ctl_path *path, struct ctl_table *table)
|
|
{
|
|
struct ctl_table_header *header;
|
|
struct ctl_table *new, **prevp;
|
|
unsigned int n, npath;
|
|
struct ctl_table_set *set;
|
|
|
|
/* Count the path components */
|
|
for (npath = 0; path[npath].procname; ++npath)
|
|
;
|
|
|
|
/*
|
|
* For each path component, allocate a 2-element ctl_table array.
|
|
* The first array element will be filled with the sysctl entry
|
|
* for this, the second will be the sentinel (procname == 0).
|
|
*
|
|
* We allocate everything in one go so that we don't have to
|
|
* worry about freeing additional memory in unregister_sysctl_table.
|
|
*/
|
|
header = kzalloc(sizeof(struct ctl_table_header) +
|
|
(2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
|
|
if (!header)
|
|
return NULL;
|
|
|
|
new = (struct ctl_table *) (header + 1);
|
|
|
|
/* Now connect the dots */
|
|
prevp = &header->ctl_table;
|
|
for (n = 0; n < npath; ++n, ++path) {
|
|
/* Copy the procname */
|
|
new->procname = path->procname;
|
|
new->mode = 0555;
|
|
|
|
*prevp = new;
|
|
prevp = &new->child;
|
|
|
|
new += 2;
|
|
}
|
|
*prevp = table;
|
|
header->ctl_table_arg = table;
|
|
|
|
INIT_LIST_HEAD(&header->ctl_entry);
|
|
header->used = 0;
|
|
header->unregistering = NULL;
|
|
header->root = root;
|
|
sysctl_set_parent(NULL, header->ctl_table);
|
|
header->count = 1;
|
|
#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
|
|
if (sysctl_check_table(namespaces, header->ctl_table)) {
|
|
kfree(header);
|
|
return NULL;
|
|
}
|
|
#endif
|
|
spin_lock(&sysctl_lock);
|
|
header->set = lookup_header_set(root, namespaces);
|
|
header->attached_by = header->ctl_table;
|
|
header->attached_to = root_table;
|
|
header->parent = &root_table_header;
|
|
for (set = header->set; set; set = set->parent) {
|
|
struct ctl_table_header *p;
|
|
list_for_each_entry(p, &set->list, ctl_entry) {
|
|
if (p->unregistering)
|
|
continue;
|
|
try_attach(p, header);
|
|
}
|
|
}
|
|
header->parent->count++;
|
|
list_add_tail(&header->ctl_entry, &header->set->list);
|
|
spin_unlock(&sysctl_lock);
|
|
|
|
return header;
|
|
}
|
|
|
|
/**
|
|
* register_sysctl_table_path - register a sysctl table hierarchy
|
|
* @path: The path to the directory the sysctl table is in.
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* See __register_sysctl_paths for more details.
|
|
*/
|
|
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
|
|
struct ctl_table *table)
|
|
{
|
|
return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
|
|
path, table);
|
|
}
|
|
EXPORT_SYMBOL(register_sysctl_paths);
|
|
|
|
/**
|
|
* register_sysctl_table - register a sysctl table hierarchy
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* See register_sysctl_paths for more details.
|
|
*/
|
|
struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
|
|
{
|
|
static const struct ctl_path null_path[] = { {} };
|
|
|
|
return register_sysctl_paths(null_path, table);
|
|
}
|
|
EXPORT_SYMBOL(register_sysctl_table);
|
|
|
|
/**
|
|
* unregister_sysctl_table - unregister a sysctl table hierarchy
|
|
* @header: the header returned from register_sysctl_table
|
|
*
|
|
* Unregisters the sysctl table and all children. proc entries may not
|
|
* actually be removed until they are no longer used by anyone.
|
|
*/
|
|
void unregister_sysctl_table(struct ctl_table_header * header)
|
|
{
|
|
might_sleep();
|
|
|
|
if (header == NULL)
|
|
return;
|
|
|
|
spin_lock(&sysctl_lock);
|
|
start_unregistering(header);
|
|
if (!--header->parent->count) {
|
|
WARN_ON(1);
|
|
kfree_rcu(header->parent, rcu);
|
|
}
|
|
if (!--header->count)
|
|
kfree_rcu(header, rcu);
|
|
spin_unlock(&sysctl_lock);
|
|
}
|
|
EXPORT_SYMBOL(unregister_sysctl_table);
|
|
|
|
void setup_sysctl_set(struct ctl_table_set *p,
|
|
struct ctl_table_set *parent,
|
|
int (*is_seen)(struct ctl_table_set *))
|
|
{
|
|
INIT_LIST_HEAD(&p->list);
|
|
p->parent = parent ? parent : &sysctl_table_root.default_set;
|
|
p->is_seen = is_seen;
|
|
}
|
|
|
|
void retire_sysctl_set(struct ctl_table_set *set)
|
|
{
|
|
WARN_ON(!list_empty(&set->list));
|
|
}
|
|
|
|
int __init proc_sys_init(void)
|
|
{
|
|
struct proc_dir_entry *proc_sys_root;
|
|
|
|
proc_sys_root = proc_mkdir("sys", NULL);
|
|
proc_sys_root->proc_iops = &proc_sys_dir_operations;
|
|
proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
|
|
proc_sys_root->nlink = 0;
|
|
|
|
return sysctl_init();
|
|
}
|