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path: root/fs/proc/proc_sysctl.c
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Diffstat (limited to 'fs/proc/proc_sysctl.c')
-rw-r--r--fs/proc/proc_sysctl.c123
1 files changed, 63 insertions, 60 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 071a71eb1a2d..e785db5fa499 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;
@@ -29,9 +29,12 @@ 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;
-/* Support for permanently empty directories */
+/*
+ * Support for permanently empty directories.
+ * Must be non-empty to avoid sharing an address with other tables.
+ */
static struct ctl_table sysctl_mount_point[] = {
- {.type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY }
+ { }
};
/**
@@ -44,18 +47,16 @@ static struct ctl_table sysctl_mount_point[] = {
*/
struct ctl_table_header *register_sysctl_mount_point(const char *path)
{
- return register_sysctl(path, sysctl_mount_point);
+ return register_sysctl_sz(path, sysctl_mount_point, 0);
}
EXPORT_SYMBOL(register_sysctl_mount_point);
-#define sysctl_is_perm_empty_ctl_table(tptr) \
- (tptr[0].type == SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
#define sysctl_is_perm_empty_ctl_header(hptr) \
- (sysctl_is_perm_empty_ctl_table(hptr->ctl_table))
+ (hptr->type == SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
#define sysctl_set_perm_empty_ctl_header(hptr) \
- (hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
+ (hptr->type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
#define sysctl_clear_perm_empty_ctl_header(hptr) \
- (hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_DEFAULT)
+ (hptr->type = SYSCTL_TABLE_TYPE_DEFAULT)
void proc_sys_poll_notify(struct ctl_table_poll *poll)
{
@@ -71,7 +72,6 @@ static struct ctl_table root_table[] = {
.procname = "",
.mode = S_IFDIR|S_IRUGO|S_IXUGO,
},
- { }
};
static struct ctl_table_root sysctl_table_root = {
.default_set.dir.header = {
@@ -211,6 +211,8 @@ static void init_header(struct ctl_table_header *head,
node++;
}
}
+ if (table == sysctl_mount_point)
+ sysctl_set_perm_empty_ctl_header(head);
}
static void erase_header(struct ctl_table_header *head)
@@ -233,8 +235,7 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
return -EROFS;
/* Am I creating a permanently empty directory? */
- if (header->ctl_table_size > 0 &&
- sysctl_is_perm_empty_ctl_table(header->ctl_table)) {
+ if (sysctl_is_perm_empty_ctl_header(header)) {
if (!RB_EMPTY_ROOT(&dir->root))
return -EINVAL;
sysctl_set_perm_empty_ctl_header(dir_h);
@@ -466,7 +467,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
head->count++;
spin_unlock(&sysctl_lock);
- inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode);
+ simple_inode_init_ts(inode);
inode->i_mode = table->mode;
if (!S_ISDIR(table->mode)) {
inode->i_mode |= S_IFREG;
@@ -533,13 +534,8 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
goto out;
}
- inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
- if (IS_ERR(inode)) {
- err = ERR_CAST(inode);
- goto out;
- }
-
d_set_d_op(dentry, &proc_sys_dentry_operations);
+ inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
err = d_splice_alias(inode, dentry);
out:
@@ -697,13 +693,8 @@ static bool proc_sys_fill_cache(struct file *file,
return false;
if (d_in_lookup(child)) {
struct dentry *res;
- inode = proc_sys_make_inode(dir->d_sb, head, table);
- if (IS_ERR(inode)) {
- d_lookup_done(child);
- dput(child);
- return false;
- }
d_set_d_op(child, &proc_sys_dentry_operations);
+ inode = proc_sys_make_inode(dir->d_sb, head, table);
res = d_splice_alias(inode, child);
d_lookup_done(child);
if (unlikely(res)) {
@@ -920,17 +911,21 @@ static int proc_sys_compare(const struct dentry *dentry,
struct ctl_table_header *head;
struct inode *inode;
- /* Although proc doesn't have negative dentries, rcu-walk means
- * that inode here can be NULL */
- /* AV: can it, indeed? */
- inode = d_inode_rcu(dentry);
- 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);
+
+ // false positive is fine here - we'll recheck anyway
+ if (d_in_lookup(dentry))
+ return 0;
+
+ inode = d_inode_rcu(dentry);
+ // we just might have run into dentry in the middle of __dentry_kill()
+ if (!inode)
+ return 1;
+
+ head = READ_ONCE(PROC_I(inode)->sysctl);
return !head || !sysctl_is_seen(head);
}
@@ -963,14 +958,14 @@ 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;
@@ -1105,6 +1100,7 @@ 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) ||
@@ -1116,6 +1112,19 @@ 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) {
@@ -1131,6 +1140,8 @@ 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) ||
@@ -1166,18 +1177,16 @@ 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);
@@ -1185,8 +1194,8 @@ 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) {
@@ -1200,7 +1209,7 @@ 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;
}
@@ -1213,7 +1222,7 @@ static bool get_links(struct ctl_dir *dir,
struct ctl_table *entry, *link;
if (header->ctl_table_size == 0 ||
- sysctl_is_perm_empty_ctl_table(header->ctl_table))
+ sysctl_is_perm_empty_ctl_header(header))
return true;
/* Are there links available for every entry in table? */
@@ -1312,28 +1321,23 @@ 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
@@ -1341,8 +1345,7 @@ 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 -
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-29 07:44:26 +0300