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Date: Thu, 26 Jan 2012 20:51:40 -0800
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: <linux-kernel@...r.kernel.org>
Cc: <linux-fsdevel@...r.kernel.org>, <netdev@...r.kernel.org>,
Lucian Adrian Grijincu <lucian.grijincu@...il.com>,
Damien Millescamps <damien.millescamps@...nd.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 04/29] sysctl: Move the implementation into fs/proc/proc_sysctl.c
Move the core sysctl code from kernel/sysctl.c and kernel/sysctl_check.c
into fs/proc/proc_sysctl.c.
Currently sysctl maintenance is hampered by the sysctl implementation
being split across 3 files with artificial layering between them.
Consolidate the entire sysctl implementation into 1 file so that
it is easier to see what is going on and hopefully allowing for
simpler maintenance.
For functions that are now only used in fs/proc/proc_sysctl.c remove
their declarations from sysctl.h and make them static in fs/proc/proc_sysctl.c
Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
---
fs/proc/internal.h | 3 +
fs/proc/proc_sysctl.c | 622 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/sysctl.h | 16 --
kernel/Makefile | 1 -
kernel/sysctl.c | 464 ------------------------------------
kernel/sysctl_check.c | 160 -------------
6 files changed, 625 insertions(+), 641 deletions(-)
delete mode 100644 kernel/sysctl_check.c
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 2925775..3b5ecd9 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -10,12 +10,15 @@
*/
#include <linux/proc_fs.h>
+struct ctl_table_header;
extern struct proc_dir_entry proc_root;
#ifdef CONFIG_PROC_SYSCTL
extern int proc_sys_init(void);
+extern void sysctl_head_put(struct ctl_table_header *head);
#else
static inline void proc_sys_init(void) { }
+static inline void sysctl_head_put(struct ctl_table_header *head) { }
#endif
#ifdef CONFIG_NET
extern int proc_net_init(void);
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 9d29d28..06e6f10 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -7,6 +7,7 @@
#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;
@@ -24,6 +25,209 @@ void proc_sys_poll_notify(struct ctl_table_poll *poll)
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)
{
@@ -435,6 +639,21 @@ 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,
@@ -460,6 +679,409 @@ static const struct dentry_operations proc_sys_dentry_operations = {
.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;
+}
+
+
int __init proc_sys_init(void)
{
struct proc_dir_entry *proc_sys_root;
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 5e3532e..08cabbf 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -1073,17 +1073,6 @@ extern void setup_sysctl_set(struct ctl_table_set *p,
struct ctl_table_set *parent,
int (*is_seen)(struct ctl_table_set *));
-extern void sysctl_head_get(struct ctl_table_header *);
-extern void sysctl_head_put(struct ctl_table_header *);
-extern int sysctl_is_seen(struct ctl_table_header *);
-extern struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *);
-extern struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev);
-extern struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
- struct ctl_table_header *prev);
-extern void sysctl_head_finish(struct ctl_table_header *prev);
-extern int sysctl_perm(struct ctl_table_root *root,
- struct ctl_table *table, int op);
-
void register_sysctl_root(struct ctl_table_root *root);
struct ctl_table_header *__register_sysctl_paths(
struct ctl_table_root *root, struct nsproxy *namespaces,
@@ -1093,7 +1082,6 @@ struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
struct ctl_table *table);
void unregister_sysctl_table(struct ctl_table_header * table);
-int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table);
extern int sysctl_init(void);
#else /* CONFIG_SYSCTL */
@@ -1118,10 +1106,6 @@ static inline void setup_sysctl_set(struct ctl_table_set *p,
{
}
-static inline void sysctl_head_put(struct ctl_table_header *head)
-{
-}
-
#endif /* CONFIG_SYSCTL */
#endif /* __KERNEL__ */
diff --git a/kernel/Makefile b/kernel/Makefile
index 2d9de86..cb41b95 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -27,7 +27,6 @@ obj-y += power/
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
-obj-$(CONFIG_SYSCTL_SYSCALL_CHECK) += sysctl_check.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ad46024..b774909 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -192,20 +192,6 @@ static int sysrq_sysctl_handler(ctl_table *table, int write,
#endif
-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 struct ctl_table kern_table[];
static struct ctl_table vm_table[];
static struct ctl_table fs_table[];
@@ -1559,459 +1545,12 @@ static struct ctl_table dev_table[] = {
{ }
};
-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);
-}
-
-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);
-}
-
-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;
-}
-
-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;
-}
-
-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;
-}
-
-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;
-}
-
-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);
- }
-}
-
int __init sysctl_init(void)
{
register_sysctl_table(sysctl_base_table);
return 0;
}
-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;
- }
-}
-
-/**
- * __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);
-}
-
-/**
- * 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);
-}
-
-/**
- * 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);
-}
-
-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;
-}
-
-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;
-}
-
#endif /* CONFIG_SYSCTL */
/*
@@ -2977,6 +2516,3 @@ EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
EXPORT_SYMBOL(proc_dostring);
EXPORT_SYMBOL(proc_doulongvec_minmax);
EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
-EXPORT_SYMBOL(register_sysctl_table);
-EXPORT_SYMBOL(register_sysctl_paths);
-EXPORT_SYMBOL(unregister_sysctl_table);
diff --git a/kernel/sysctl_check.c b/kernel/sysctl_check.c
deleted file mode 100644
index 362da65..0000000
--- a/kernel/sysctl_check.c
+++ /dev/null
@@ -1,160 +0,0 @@
-#include <linux/stat.h>
-#include <linux/sysctl.h>
-#include "../fs/xfs/xfs_sysctl.h"
-#include <linux/sunrpc/debug.h>
-#include <linux/string.h>
-#include <net/ip_vs.h>
-
-
-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");
-}
-
-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;
-}
--
1.7.2.5
--
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