Merge tag 'sysctl-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl

Pull sysctl updates from Joel Granados:

 - Remove "->procname == NULL" check when iterating through sysctl table
   arrays

   Removing sentinels in ctl_table arrays reduces the build time size
   and runtime memory consumed by ~64 bytes per array. With all
   ctl_table sentinels gone, the additional check for ->procname == NULL
   that worked in tandem with the ARRAY_SIZE to calculate the size of
   the ctl_table arrays is no longer needed and has been removed. The
   sysctl register functions now returns an error if a sentinel is used.

 - Preparation patches for sysctl constification

   Constifying ctl_table structs prevents the modification of
   proc_handler function pointers as they would reside in .rodata. The
   ctl_table arguments in sysctl utility functions are const qualified
   in preparation for a future treewide proc_handler argument
   constification commit.

 - Misc fixes

   Increase robustness of set_ownership by providing sane default
   ownership values in case the callee doesn't set them. Bound check
   proc_dou8vec_minmax to avoid loading buggy modules and give sysctl
   testing module a name to avoid compiler complaints.

* tag 'sysctl-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
  sysctl: Warn on an empty procname element
  sysctl: Remove ctl_table sentinel code comments
  sysctl: Remove "child" sysctl code comments
  sysctl: Remove superfluous empty allocations from sysctl internals
  sysctl: Replace nr_entries with ctl_table_size in new_links
  sysctl: Remove check for sentinel element in ctl_table arrays
  mm profiling: Remove superfluous sentinel element from ctl_table
  locking: Remove superfluous sentinel element from kern_lockdep_table
  sysctl: Add module description to sysctl-testing
  sysctl: constify ctl_table arguments of utility function
  utsname: constify ctl_table arguments of utility function
  sysctl: move the extra1/2 boundary check of u8 to sysctl_check_table_array
  sysctl: always initialize i_uid/i_gid

1 files changed, 38 insertions, 32 deletions

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index b1c2c0b82116..9553e77c9d31 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -21,7 +21,7 @@
 
 #define list_for_each_table_entry(entry, header)	\
 	entry = header->ctl_table;			\
-	for (size_t i = 0 ; i < header->ctl_table_size && entry->procname; ++i, entry++)
+	for (size_t i = 0 ; i < header->ctl_table_size; ++i, entry++)
 
 static const struct dentry_operations proc_sys_dentry_operations;
 static const struct file_operations proc_sys_file_operations;
@@ -476,12 +476,10 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
 			make_empty_dir_inode(inode);
 	}
 
+	inode->i_uid = GLOBAL_ROOT_UID;
+	inode->i_gid = GLOBAL_ROOT_GID;
 	if (root->set_ownership)
 		root->set_ownership(head, &inode->i_uid, &inode->i_gid);
-	else {
-		inode->i_uid = GLOBAL_ROOT_UID;
-		inode->i_gid = GLOBAL_ROOT_GID;
-	}
 
 	return inode;
 }
@@ -951,14 +949,14 @@ static struct ctl_dir *new_dir(struct ctl_table_set *set,
 	char *new_name;
 
 	new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) +
-		      sizeof(struct ctl_table)*2 +  namelen + 1,
+		      sizeof(struct ctl_table) +  namelen + 1,
 		      GFP_KERNEL);
 	if (!new)
 		return NULL;
 
 	node = (struct ctl_node *)(new + 1);
 	table = (struct ctl_table *)(node + 1);
-	new_name = (char *)(table + 2);
+	new_name = (char *)(table + 1);
 	memcpy(new_name, name, namelen);
 	table[0].procname = new_name;
 	table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
@@ -1093,6 +1091,7 @@ static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
 
 static int sysctl_check_table_array(const char *path, struct ctl_table *table)
 {
+	unsigned int extra;
 	int err = 0;
 
 	if ((table->proc_handler == proc_douintvec) ||
@@ -1104,6 +1103,19 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
 	if (table->proc_handler == proc_dou8vec_minmax) {
 		if (table->maxlen != sizeof(u8))
 			err |= sysctl_err(path, table, "array not allowed");
+
+		if (table->extra1) {
+			extra = *(unsigned int *) table->extra1;
+			if (extra > 255U)
+				err |= sysctl_err(path, table,
+						"range value too large for proc_dou8vec_minmax");
+		}
+		if (table->extra2) {
+			extra = *(unsigned int *) table->extra2;
+			if (extra > 255U)
+				err |= sysctl_err(path, table,
+						"range value too large for proc_dou8vec_minmax");
+		}
 	}
 
 	if (table->proc_handler == proc_dobool) {
@@ -1119,6 +1131,8 @@ static int sysctl_check_table(const char *path, struct ctl_table_header *header)
 	struct ctl_table *entry;
 	int err = 0;
 	list_for_each_table_entry(entry, header) {
+		if (!entry->procname)
+			err |= sysctl_err(path, entry, "procname is null");
 		if ((entry->proc_handler == proc_dostring) ||
 		    (entry->proc_handler == proc_dobool) ||
 		    (entry->proc_handler == proc_dointvec) ||
@@ -1154,18 +1168,16 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_
 	struct ctl_table_header *links;
 	struct ctl_node *node;
 	char *link_name;
-	int nr_entries, name_bytes;
+	int name_bytes;
 
 	name_bytes = 0;
-	nr_entries = 0;
 	list_for_each_table_entry(entry, head) {
-		nr_entries++;
 		name_bytes += strlen(entry->procname) + 1;
 	}
 
 	links = kzalloc(sizeof(struct ctl_table_header) +
-			sizeof(struct ctl_node)*nr_entries +
-			sizeof(struct ctl_table)*(nr_entries + 1) +
+			sizeof(struct ctl_node)*head->ctl_table_size +
+			sizeof(struct ctl_table)*head->ctl_table_size +
 			name_bytes,
 			GFP_KERNEL);
 
@@ -1173,8 +1185,8 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_
 		return NULL;
 
 	node = (struct ctl_node *)(links + 1);
-	link_table = (struct ctl_table *)(node + nr_entries);
-	link_name = (char *)&link_table[nr_entries + 1];
+	link_table = (struct ctl_table *)(node + head->ctl_table_size);
+	link_name = (char *)(link_table + head->ctl_table_size);
 	link = link_table;
 
 	list_for_each_table_entry(entry, head) {
@@ -1188,7 +1200,7 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_
 	}
 	init_header(links, dir->header.root, dir->header.set, node, link_table,
 		    head->ctl_table_size);
-	links->nreg = nr_entries;
+	links->nreg = head->ctl_table_size;
 
 	return links;
 }
@@ -1300,28 +1312,23 @@ static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path)
  * __register_sysctl_table - register a leaf sysctl table
  * @set: Sysctl tree to register on
  * @path: The path to the directory the sysctl table is in.
- * @table: the top-level table structure without any child. This table
- * 	 should not be free'd after registration. So it should not be
- * 	 used on stack. It can either be a global or dynamically allocated
- * 	 by the caller and free'd later after sysctl unregistration.
+ *
+ * @table: the top-level table structure. This table should not be free'd
+ *         after registration. So it should not be used on stack. It can either
+ *         be a global or dynamically allocated by the caller and free'd later
+ *         after sysctl unregistration.
  * @table_size : The number of elements in table
  *
  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
- * array. A completely 0 filled entry terminates the table.
+ * array.
  *
  * 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
- *
- * child - must be %NULL.
- *
+ * 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
+ * type     - Defines the target type (described in struct definition)
  * proc_handler - the text handler routine (described below)
  *
  * extra1, extra2 - extra pointers usable by the proc handler routines
@@ -1329,8 +1336,7 @@ static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path)
  * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org
  *
  * Leaf nodes in the sysctl tree will be represented by a single file
- * under /proc; non-leaf nodes (where child is not NULL) are not allowed,
- * sysctl_check_table() verifies this.
+ * under /proc; non-leaf nodes are not allowed.
  *
  * There must be a proc_handler routine for any terminal nodes.
  * Several default handlers are available to cover common cases -