| /* |
| * /proc/sys support |
| */ |
| #include <linux/init.h> |
| #include <linux/sysctl.h> |
| #include <linux/poll.h> |
| #include <linux/proc_fs.h> |
| #include <linux/security.h> |
| #include <linux/namei.h> |
| #include <linux/module.h> |
| #include "internal.h" |
| |
| static const struct dentry_operations proc_sys_dentry_operations; |
| static const struct file_operations proc_sys_file_operations; |
| static const struct inode_operations proc_sys_inode_operations; |
| static const struct file_operations proc_sys_dir_file_operations; |
| static const struct inode_operations proc_sys_dir_operations; |
| |
| void proc_sys_poll_notify(struct ctl_table_poll *poll) |
| { |
| if (!poll) |
| return; |
| |
| atomic_inc(&poll->event); |
| wake_up_interruptible(&poll->wait); |
| } |
| |
| static struct ctl_table root_table[1]; |
| static struct ctl_table_root sysctl_table_root; |
| static struct ctl_table_header root_table_header = { |
| {{.count = 1, |
| .ctl_table = root_table, |
| .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, |
| .root = &sysctl_table_root, |
| .set = &sysctl_table_root.default_set, |
| }; |
| static struct ctl_table_root sysctl_table_root = { |
| .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list), |
| .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry), |
| }; |
| |
| static DEFINE_SPINLOCK(sysctl_lock); |
| |
| /* called under sysctl_lock */ |
| static int use_table(struct ctl_table_header *p) |
| { |
| if (unlikely(p->unregistering)) |
| return 0; |
| p->used++; |
| return 1; |
| } |
| |
| /* called under sysctl_lock */ |
| static void unuse_table(struct ctl_table_header *p) |
| { |
| if (!--p->used) |
| if (unlikely(p->unregistering)) |
| complete(p->unregistering); |
| } |
| |
| /* called under sysctl_lock, will reacquire if has to wait */ |
| static void start_unregistering(struct ctl_table_header *p) |
| { |
| /* |
| * if p->used is 0, nobody will ever touch that entry again; |
| * we'll eliminate all paths to it before dropping sysctl_lock |
| */ |
| if (unlikely(p->used)) { |
| struct completion wait; |
| init_completion(&wait); |
| p->unregistering = &wait; |
| spin_unlock(&sysctl_lock); |
| wait_for_completion(&wait); |
| spin_lock(&sysctl_lock); |
| } else { |
| /* anything non-NULL; we'll never dereference it */ |
| p->unregistering = ERR_PTR(-EINVAL); |
| } |
| /* |
| * do not remove from the list until nobody holds it; walking the |
| * list in do_sysctl() relies on that. |
| */ |
| list_del_init(&p->ctl_entry); |
| } |
| |
| static void sysctl_head_get(struct ctl_table_header *head) |
| { |
| spin_lock(&sysctl_lock); |
| head->count++; |
| spin_unlock(&sysctl_lock); |
| } |
| |
| void sysctl_head_put(struct ctl_table_header *head) |
| { |
| spin_lock(&sysctl_lock); |
| if (!--head->count) |
| kfree_rcu(head, rcu); |
| spin_unlock(&sysctl_lock); |
| } |
| |
| static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) |
| { |
| if (!head) |
| BUG(); |
| spin_lock(&sysctl_lock); |
| if (!use_table(head)) |
| head = ERR_PTR(-ENOENT); |
| spin_unlock(&sysctl_lock); |
| return head; |
| } |
| |
| static void sysctl_head_finish(struct ctl_table_header *head) |
| { |
| if (!head) |
| return; |
| spin_lock(&sysctl_lock); |
| unuse_table(head); |
| spin_unlock(&sysctl_lock); |
| } |
| |
| static struct ctl_table_set * |
| lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces) |
| { |
| struct ctl_table_set *set = &root->default_set; |
| if (root->lookup) |
| set = root->lookup(root, namespaces); |
| return set; |
| } |
| |
| static struct list_head * |
| lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces) |
| { |
| struct ctl_table_set *set = lookup_header_set(root, namespaces); |
| return &set->list; |
| } |
| |
| static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces, |
| struct ctl_table_header *prev) |
| { |
| struct ctl_table_root *root; |
| struct list_head *header_list; |
| struct ctl_table_header *head; |
| struct list_head *tmp; |
| |
| spin_lock(&sysctl_lock); |
| if (prev) { |
| head = prev; |
| tmp = &prev->ctl_entry; |
| unuse_table(prev); |
| goto next; |
| } |
| tmp = &root_table_header.ctl_entry; |
| for (;;) { |
| head = list_entry(tmp, struct ctl_table_header, ctl_entry); |
| |
| if (!use_table(head)) |
| goto next; |
| spin_unlock(&sysctl_lock); |
| return head; |
| next: |
| root = head->root; |
| tmp = tmp->next; |
| header_list = lookup_header_list(root, namespaces); |
| if (tmp != header_list) |
| continue; |
| |
| do { |
| root = list_entry(root->root_list.next, |
| struct ctl_table_root, root_list); |
| if (root == &sysctl_table_root) |
| goto out; |
| header_list = lookup_header_list(root, namespaces); |
| } while (list_empty(header_list)); |
| tmp = header_list->next; |
| } |
| out: |
| spin_unlock(&sysctl_lock); |
| return NULL; |
| } |
| |
| static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev) |
| { |
| return __sysctl_head_next(current->nsproxy, prev); |
| } |
| |
| void register_sysctl_root(struct ctl_table_root *root) |
| { |
| spin_lock(&sysctl_lock); |
| list_add_tail(&root->root_list, &sysctl_table_root.root_list); |
| spin_unlock(&sysctl_lock); |
| } |
| |
| /* |
| * sysctl_perm does NOT grant the superuser all rights automatically, because |
| * some sysctl variables are readonly even to root. |
| */ |
| |
| static int test_perm(int mode, int op) |
| { |
| if (!current_euid()) |
| mode >>= 6; |
| else if (in_egroup_p(0)) |
| mode >>= 3; |
| if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) |
| return 0; |
| return -EACCES; |
| } |
| |
| static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op) |
| { |
| int mode; |
| |
| if (root->permissions) |
| mode = root->permissions(root, current->nsproxy, table); |
| else |
| mode = table->mode; |
| |
| return test_perm(mode, op); |
| } |
| |
| static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table) |
| { |
| for (; table->procname; table++) { |
| table->parent = parent; |
| if (table->child) |
| sysctl_set_parent(table, table->child); |
| } |
| } |
| |
| |
| static struct inode *proc_sys_make_inode(struct super_block *sb, |
| struct ctl_table_header *head, struct ctl_table *table) |
| { |
| struct inode *inode; |
| struct proc_inode *ei; |
| |
| inode = new_inode(sb); |
| if (!inode) |
| goto out; |
| |
| inode->i_ino = get_next_ino(); |
| |
| sysctl_head_get(head); |
| ei = PROC_I(inode); |
| ei->sysctl = head; |
| ei->sysctl_entry = table; |
| |
| inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; |
| inode->i_mode = table->mode; |
| if (!table->child) { |
| inode->i_mode |= S_IFREG; |
| inode->i_op = &proc_sys_inode_operations; |
| inode->i_fop = &proc_sys_file_operations; |
| } else { |
| inode->i_mode |= S_IFDIR; |
| inode->i_op = &proc_sys_dir_operations; |
| inode->i_fop = &proc_sys_dir_file_operations; |
| } |
| out: |
| return inode; |
| } |
| |
| static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name) |
| { |
| for ( ; p->procname; p++) { |
| if (strlen(p->procname) != name->len) |
| continue; |
| |
| if (memcmp(p->procname, name->name, name->len) != 0) |
| continue; |
| |
| /* I have a match */ |
| return p; |
| } |
| return NULL; |
| } |
| |
| static struct ctl_table_header *grab_header(struct inode *inode) |
| { |
| if (PROC_I(inode)->sysctl) |
| return sysctl_head_grab(PROC_I(inode)->sysctl); |
| else |
| return sysctl_head_next(NULL); |
| } |
| |
| static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, |
| struct nameidata *nd) |
| { |
| struct ctl_table_header *head = grab_header(dir); |
| struct ctl_table *table = PROC_I(dir)->sysctl_entry; |
| struct ctl_table_header *h = NULL; |
| struct qstr *name = &dentry->d_name; |
| struct ctl_table *p; |
| struct inode *inode; |
| struct dentry *err = ERR_PTR(-ENOENT); |
| |
| if (IS_ERR(head)) |
| return ERR_CAST(head); |
| |
| if (table && !table->child) { |
| WARN_ON(1); |
| goto out; |
| } |
| |
| table = table ? table->child : head->ctl_table; |
| |
| p = find_in_table(table, name); |
| if (!p) { |
| for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) { |
| if (h->attached_to != table) |
| continue; |
| p = find_in_table(h->attached_by, name); |
| if (p) |
| break; |
| } |
| } |
| |
| if (!p) |
| goto out; |
| |
| err = ERR_PTR(-ENOMEM); |
| inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); |
| if (h) |
| sysctl_head_finish(h); |
| |
| if (!inode) |
| goto out; |
| |
| err = NULL; |
| d_set_d_op(dentry, &proc_sys_dentry_operations); |
| d_add(dentry, inode); |
| |
| out: |
| sysctl_head_finish(head); |
| return err; |
| } |
| |
| static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, |
| size_t count, loff_t *ppos, int write) |
| { |
| struct inode *inode = filp->f_path.dentry->d_inode; |
| struct ctl_table_header *head = grab_header(inode); |
| struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
| ssize_t error; |
| size_t res; |
| |
| if (IS_ERR(head)) |
| return PTR_ERR(head); |
| |
| /* |
| * At this point we know that the sysctl was not unregistered |
| * and won't be until we finish. |
| */ |
| error = -EPERM; |
| if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ)) |
| goto out; |
| |
| /* if that can happen at all, it should be -EINVAL, not -EISDIR */ |
| error = -EINVAL; |
| if (!table->proc_handler) |
| goto out; |
| |
| /* careful: calling conventions are nasty here */ |
| res = count; |
| error = table->proc_handler(table, write, buf, &res, ppos); |
| if (!error) |
| error = res; |
| out: |
| sysctl_head_finish(head); |
| |
| return error; |
| } |
| |
| static ssize_t proc_sys_read(struct file *filp, char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); |
| } |
| |
| static ssize_t proc_sys_write(struct file *filp, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); |
| } |
| |
| static int proc_sys_open(struct inode *inode, struct file *filp) |
| { |
| struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
| |
| if (table->poll) |
| filp->private_data = proc_sys_poll_event(table->poll); |
| |
| return 0; |
| } |
| |
| static unsigned int proc_sys_poll(struct file *filp, poll_table *wait) |
| { |
| struct inode *inode = filp->f_path.dentry->d_inode; |
| struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
| unsigned long event = (unsigned long)filp->private_data; |
| unsigned int ret = DEFAULT_POLLMASK; |
| |
| if (!table->proc_handler) |
| goto out; |
| |
| if (!table->poll) |
| goto out; |
| |
| poll_wait(filp, &table->poll->wait, wait); |
| |
| if (event != atomic_read(&table->poll->event)) { |
| filp->private_data = proc_sys_poll_event(table->poll); |
| ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI; |
| } |
| |
| out: |
| return ret; |
| } |
| |
| static int proc_sys_fill_cache(struct file *filp, void *dirent, |
| filldir_t filldir, |
| struct ctl_table_header *head, |
| struct ctl_table *table) |
| { |
| struct dentry *child, *dir = filp->f_path.dentry; |
| struct inode *inode; |
| struct qstr qname; |
| ino_t ino = 0; |
| unsigned type = DT_UNKNOWN; |
| |
| qname.name = table->procname; |
| qname.len = strlen(table->procname); |
| qname.hash = full_name_hash(qname.name, qname.len); |
| |
| child = d_lookup(dir, &qname); |
| if (!child) { |
| child = d_alloc(dir, &qname); |
| if (child) { |
| inode = proc_sys_make_inode(dir->d_sb, head, table); |
| if (!inode) { |
| dput(child); |
| return -ENOMEM; |
| } else { |
| d_set_d_op(child, &proc_sys_dentry_operations); |
| d_add(child, inode); |
| } |
| } else { |
| return -ENOMEM; |
| } |
| } |
| inode = child->d_inode; |
| ino = inode->i_ino; |
| type = inode->i_mode >> 12; |
| dput(child); |
| return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type); |
| } |
| |
| static int scan(struct ctl_table_header *head, ctl_table *table, |
| unsigned long *pos, struct file *file, |
| void *dirent, filldir_t filldir) |
| { |
| |
| for (; table->procname; table++, (*pos)++) { |
| int res; |
| |
| if (*pos < file->f_pos) |
| continue; |
| |
| res = proc_sys_fill_cache(file, dirent, filldir, head, table); |
| if (res) |
| return res; |
| |
| file->f_pos = *pos + 1; |
| } |
| return 0; |
| } |
| |
| static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir) |
| { |
| struct dentry *dentry = filp->f_path.dentry; |
| struct inode *inode = dentry->d_inode; |
| struct ctl_table_header *head = grab_header(inode); |
| struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
| struct ctl_table_header *h = NULL; |
| unsigned long pos; |
| int ret = -EINVAL; |
| |
| if (IS_ERR(head)) |
| return PTR_ERR(head); |
| |
| if (table && !table->child) { |
| WARN_ON(1); |
| goto out; |
| } |
| |
| table = table ? table->child : head->ctl_table; |
| |
| ret = 0; |
| /* Avoid a switch here: arm builds fail with missing __cmpdi2 */ |
| if (filp->f_pos == 0) { |
| if (filldir(dirent, ".", 1, filp->f_pos, |
| inode->i_ino, DT_DIR) < 0) |
| goto out; |
| filp->f_pos++; |
| } |
| if (filp->f_pos == 1) { |
| if (filldir(dirent, "..", 2, filp->f_pos, |
| parent_ino(dentry), DT_DIR) < 0) |
| 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_table - register a sysctl table |
| * @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_table( |
| struct ctl_table_root *root, |
| struct nsproxy *namespaces, |
| const char *path, struct ctl_table *table) |
| { |
| struct ctl_table_header *header; |
| struct ctl_table *new, **prevp; |
| const char *name, *nextname; |
| unsigned int npath = 0; |
| struct ctl_table_set *set; |
| size_t path_bytes = 0; |
| char *new_name; |
| |
| /* Count the path components */ |
| for (name = path; name; name = nextname) { |
| int namelen; |
| nextname = strchr(name, '/'); |
| if (nextname) { |
| namelen = nextname - name; |
| nextname++; |
| } else { |
| namelen = strlen(name); |
| } |
| if (namelen == 0) |
| continue; |
| path_bytes += namelen + 1; |
| 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) + path_bytes + |
| (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL); |
| if (!header) |
| return NULL; |
| |
| new = (struct ctl_table *) (header + 1); |
| new_name = (char *)(new + (2 * npath)); |
| |
| /* Now connect the dots */ |
| prevp = &header->ctl_table; |
| for (name = path; name; name = nextname) { |
| int namelen; |
| nextname = strchr(name, '/'); |
| if (nextname) { |
| namelen = nextname - name; |
| nextname++; |
| } else { |
| namelen = strlen(name); |
| } |
| if (namelen == 0) |
| continue; |
| memcpy(new_name, name, namelen); |
| new_name[namelen] = '\0'; |
| |
| new->procname = new_name; |
| new->mode = 0555; |
| |
| *prevp = new; |
| prevp = &new->child; |
| |
| new += 2; |
| new_name += namelen + 1; |
| } |
| *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; |
| set = header->set; |
| root = header->root; |
| for (;;) { |
| struct ctl_table_header *p; |
| list_for_each_entry(p, &set->list, ctl_entry) { |
| if (p->unregistering) |
| continue; |
| try_attach(p, header); |
| } |
| if (root == &sysctl_table_root) |
| break; |
| root = list_entry(root->root_list.prev, |
| struct ctl_table_root, root_list); |
| set = lookup_header_set(root, namespaces); |
| } |
| header->parent->count++; |
| list_add_tail(&header->ctl_entry, &header->set->list); |
| spin_unlock(&sysctl_lock); |
| |
| return header; |
| } |
| |
| static char *append_path(const char *path, char *pos, const char *name) |
| { |
| int namelen; |
| namelen = strlen(name); |
| if (((pos - path) + namelen + 2) >= PATH_MAX) |
| return NULL; |
| memcpy(pos, name, namelen); |
| pos[namelen] = '/'; |
| pos[namelen + 1] = '\0'; |
| pos += namelen + 1; |
| return pos; |
| } |
| |
| /** |
| * __register_sysctl_paths - register a sysctl table 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. |
| * |
| * See __register_sysctl_table for more details. |
| */ |
| 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 = NULL; |
| const struct ctl_path *component; |
| char *new_path, *pos; |
| |
| pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); |
| if (!new_path) |
| return NULL; |
| |
| pos[0] = '\0'; |
| for (component = path; component->procname; component++) { |
| pos = append_path(new_path, pos, component->procname); |
| if (!pos) |
| goto out; |
| } |
| header = __register_sysctl_table(root, namespaces, new_path, table); |
| out: |
| kfree(new_path); |
| 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, |
| int (*is_seen)(struct ctl_table_set *)) |
| { |
| INIT_LIST_HEAD(&p->list); |
| 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(); |
| } |