selinux: add selinuxfs structure for object class discovery
The structure is as follows (relative to selinuxfs root): /class/file/index /class/file/perms/read /class/file/perms/write ... Each class is allocated 33 inodes, 1 for the class index and 32 for permissions. Relative to SEL_CLASS_INO_OFFSET, the inode of the index file DIV 33 is the class number. The inode of the permission file % 33 is the index of the permission for that class. Signed-off-by: Christopher J. PeBenito <cpebenito@tresys.com> Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Christopher J. PeBenito
James Morris
parent
0dd4ae516e
commit
e47c8fc582
2 changed files with 250 additions and 0 deletions
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@ -41,6 +41,7 @@ extern int selinux_mls_enabled;
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int security_load_policy(void * data, size_t len);
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#define SEL_VEC_MAX 32
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struct av_decision {
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u32 allowed;
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u32 decided;
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@ -67,6 +67,10 @@ static struct dentry *bool_dir = NULL;
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static int bool_num = 0;
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static int *bool_pending_values = NULL;
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/* global data for classes */
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static struct dentry *class_dir = NULL;
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static unsigned long last_class_ino;
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extern void selnl_notify_setenforce(int val);
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/* Check whether a task is allowed to use a security operation. */
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@ -106,6 +110,7 @@ static unsigned long sel_last_ino = SEL_INO_NEXT - 1;
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#define SEL_INITCON_INO_OFFSET 0x01000000
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#define SEL_BOOL_INO_OFFSET 0x02000000
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#define SEL_CLASS_INO_OFFSET 0x04000000
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#define SEL_INO_MASK 0x00ffffff
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#define TMPBUFLEN 12
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@ -237,6 +242,11 @@ static const struct file_operations sel_policyvers_ops = {
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/* declaration for sel_write_load */
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static int sel_make_bools(void);
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static int sel_make_classes(void);
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/* declaration for sel_make_class_dirs */
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static int sel_make_dir(struct inode *dir, struct dentry *dentry,
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unsigned long *ino);
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static ssize_t sel_read_mls(struct file *filp, char __user *buf,
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size_t count, loff_t *ppos)
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@ -287,10 +297,18 @@ static ssize_t sel_write_load(struct file * file, const char __user * buf,
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goto out;
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ret = sel_make_bools();
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if (ret) {
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length = ret;
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goto out1;
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}
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ret = sel_make_classes();
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if (ret)
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length = ret;
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else
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length = count;
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out1:
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audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
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"policy loaded auid=%u",
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audit_get_loginuid(current->audit_context));
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@ -1293,6 +1311,225 @@ static int sel_make_initcon_files(struct dentry *dir)
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return ret;
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}
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static inline unsigned int sel_div(unsigned long a, unsigned long b)
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{
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return a / b - (a % b < 0);
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}
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static inline unsigned long sel_class_to_ino(u16 class)
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{
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return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET;
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}
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static inline u16 sel_ino_to_class(unsigned long ino)
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{
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return sel_div(ino & SEL_INO_MASK, SEL_VEC_MAX + 1);
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}
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static inline unsigned long sel_perm_to_ino(u16 class, u32 perm)
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{
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return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET;
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}
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static inline u32 sel_ino_to_perm(unsigned long ino)
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{
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return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1);
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}
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static ssize_t sel_read_class(struct file * file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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ssize_t rc, len;
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char *page;
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unsigned long ino = file->f_path.dentry->d_inode->i_ino;
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page = (char *)__get_free_page(GFP_KERNEL);
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if (!page) {
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rc = -ENOMEM;
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goto out;
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}
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len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino));
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rc = simple_read_from_buffer(buf, count, ppos, page, len);
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free_page((unsigned long)page);
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out:
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return rc;
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}
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static const struct file_operations sel_class_ops = {
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.read = sel_read_class,
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};
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static ssize_t sel_read_perm(struct file * file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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ssize_t rc, len;
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char *page;
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unsigned long ino = file->f_path.dentry->d_inode->i_ino;
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page = (char *)__get_free_page(GFP_KERNEL);
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if (!page) {
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rc = -ENOMEM;
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goto out;
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}
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len = snprintf(page, PAGE_SIZE,"%d", sel_ino_to_perm(ino));
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rc = simple_read_from_buffer(buf, count, ppos, page, len);
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free_page((unsigned long)page);
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out:
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return rc;
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}
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static const struct file_operations sel_perm_ops = {
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.read = sel_read_perm,
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};
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static int sel_make_perm_files(char *objclass, int classvalue,
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struct dentry *dir)
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{
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int i, rc = 0, nperms;
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char **perms;
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rc = security_get_permissions(objclass, &perms, &nperms);
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if (rc)
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goto out;
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for (i = 0; i < nperms; i++) {
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struct inode *inode;
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struct dentry *dentry;
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dentry = d_alloc_name(dir, perms[i]);
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if (!dentry) {
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rc = -ENOMEM;
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goto out1;
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}
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inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
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if (!inode) {
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rc = -ENOMEM;
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goto out1;
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}
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inode->i_fop = &sel_perm_ops;
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/* i+1 since perm values are 1-indexed */
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inode->i_ino = sel_perm_to_ino(classvalue, i+1);
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d_add(dentry, inode);
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}
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out1:
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for (i = 0; i < nperms; i++)
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kfree(perms[i]);
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kfree(perms);
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out:
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return rc;
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}
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static int sel_make_class_dir_entries(char *classname, int index,
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struct dentry *dir)
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{
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struct dentry *dentry = NULL;
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struct inode *inode = NULL;
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int rc;
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dentry = d_alloc_name(dir, "index");
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if (!dentry) {
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rc = -ENOMEM;
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goto out;
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}
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inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
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if (!inode) {
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rc = -ENOMEM;
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goto out;
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}
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inode->i_fop = &sel_class_ops;
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inode->i_ino = sel_class_to_ino(index);
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d_add(dentry, inode);
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dentry = d_alloc_name(dir, "perms");
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if (!dentry) {
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rc = -ENOMEM;
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goto out;
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}
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rc = sel_make_dir(dir->d_inode, dentry, &last_class_ino);
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if (rc)
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goto out;
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rc = sel_make_perm_files(classname, index, dentry);
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out:
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return rc;
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}
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static void sel_remove_classes(void)
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{
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struct list_head *class_node;
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list_for_each(class_node, &class_dir->d_subdirs) {
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struct dentry *class_subdir = list_entry(class_node,
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struct dentry, d_u.d_child);
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struct list_head *class_subdir_node;
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list_for_each(class_subdir_node, &class_subdir->d_subdirs) {
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struct dentry *d = list_entry(class_subdir_node,
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struct dentry, d_u.d_child);
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if (d->d_inode)
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if (d->d_inode->i_mode & S_IFDIR)
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sel_remove_entries(d);
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}
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sel_remove_entries(class_subdir);
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}
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sel_remove_entries(class_dir);
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}
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static int sel_make_classes(void)
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{
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int rc = 0, nclasses, i;
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char **classes;
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/* delete any existing entries */
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sel_remove_classes();
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rc = security_get_classes(&classes, &nclasses);
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if (rc < 0)
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goto out;
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/* +2 since classes are 1-indexed */
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last_class_ino = sel_class_to_ino(nclasses+2);
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for (i = 0; i < nclasses; i++) {
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struct dentry *class_name_dir;
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class_name_dir = d_alloc_name(class_dir, classes[i]);
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if (!class_name_dir) {
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rc = -ENOMEM;
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goto out1;
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}
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rc = sel_make_dir(class_dir->d_inode, class_name_dir,
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&last_class_ino);
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if (rc)
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goto out1;
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/* i+1 since class values are 1-indexed */
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rc = sel_make_class_dir_entries(classes[i], i+1,
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class_name_dir);
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if (rc)
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goto out1;
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}
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out1:
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for (i = 0; i < nclasses; i++)
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kfree(classes[i]);
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kfree(classes);
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out:
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return rc;
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}
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static int sel_make_dir(struct inode *dir, struct dentry *dentry,
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unsigned long *ino)
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{
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@ -1407,6 +1644,18 @@ static int sel_fill_super(struct super_block * sb, void * data, int silent)
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if (ret)
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goto err;
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dentry = d_alloc_name(sb->s_root, "class");
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if (!dentry) {
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ret = -ENOMEM;
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goto err;
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}
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ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
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if (ret)
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goto err;
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class_dir = dentry;
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out:
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return ret;
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err:
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