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Commit e47c8fc5 authored by Christopher J. PeBenito's avatar Christopher J. PeBenito Committed by James Morris
Browse files

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: default avatarChristopher J. PeBenito <cpebenito@tresys.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 0dd4ae51

security/selinux/include/security.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ extern int selinux_mls_enabled; 


int security_load_policy(void * data, size_t len);



#define SEL_VEC_MAX 32

struct av_decision {

	u32 allowed;

	u32 decided;

security/selinux/selinuxfs.c

+249 −0
Original line number Diff line number Diff line
@@ -67,6 +67,10 @@ static struct dentry *bool_dir = NULL; 
static int bool_num = 0;

static int *bool_pending_values = NULL;



/* global data for classes */

static struct dentry *class_dir = NULL;

static unsigned long last_class_ino;



extern void selnl_notify_setenforce(int val);



/* Check whether a task is allowed to use a security operation. */
@@ -106,6 +110,7 @@ static unsigned long sel_last_ino = SEL_INO_NEXT - 1; 


#define SEL_INITCON_INO_OFFSET 	0x01000000

#define SEL_BOOL_INO_OFFSET	0x02000000

#define SEL_CLASS_INO_OFFSET	0x04000000

#define SEL_INO_MASK		0x00ffffff



#define TMPBUFLEN	12
@@ -237,6 +242,11 @@ static const struct file_operations sel_policyvers_ops = { 


/* declaration for sel_write_load */

static int sel_make_bools(void);

static int sel_make_classes(void);



/* declaration for sel_make_class_dirs */

static int sel_make_dir(struct inode *dir, struct dentry *dentry,

			unsigned long *ino);



static ssize_t sel_read_mls(struct file *filp, char __user *buf,

				size_t count, loff_t *ppos)
@@ -287,10 +297,18 @@ static ssize_t sel_write_load(struct file * file, const char __user * buf, 
		goto out;



	ret = sel_make_bools();

	if (ret) {

		length = ret;

		goto out1;

	}



	ret = sel_make_classes();

	if (ret)

		length = ret;

	else

		length = count;



out1:

	audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,

		"policy loaded auid=%u",

		audit_get_loginuid(current->audit_context));
@@ -1293,6 +1311,225 @@ static int sel_make_initcon_files(struct dentry *dir) 
	return ret;

}



static inline unsigned int sel_div(unsigned long a, unsigned long b)

{

	return a / b - (a % b < 0);

}



static inline unsigned long sel_class_to_ino(u16 class)

{

	return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET;

}



static inline u16 sel_ino_to_class(unsigned long ino)

{

	return sel_div(ino & SEL_INO_MASK, SEL_VEC_MAX + 1);

}



static inline unsigned long sel_perm_to_ino(u16 class, u32 perm)

{

	return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET;

}



static inline u32 sel_ino_to_perm(unsigned long ino)

{

	return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1);

}



static ssize_t sel_read_class(struct file * file, char __user *buf,

				size_t count, loff_t *ppos)

{

	ssize_t rc, len;

	char *page;

	unsigned long ino = file->f_path.dentry->d_inode->i_ino;



	page = (char *)__get_free_page(GFP_KERNEL);

	if (!page) {

		rc = -ENOMEM;

		goto out;

	}



	len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino));

	rc = simple_read_from_buffer(buf, count, ppos, page, len);

	free_page((unsigned long)page);

out:

	return rc;

}



static const struct file_operations sel_class_ops = {

	.read		= sel_read_class,

};



static ssize_t sel_read_perm(struct file * file, char __user *buf,

				size_t count, loff_t *ppos)

{

	ssize_t rc, len;

	char *page;

	unsigned long ino = file->f_path.dentry->d_inode->i_ino;



	page = (char *)__get_free_page(GFP_KERNEL);

	if (!page) {

		rc = -ENOMEM;

		goto out;

	}



	len = snprintf(page, PAGE_SIZE,"%d", sel_ino_to_perm(ino));

	rc = simple_read_from_buffer(buf, count, ppos, page, len);

	free_page((unsigned long)page);

out:

	return rc;

}



static const struct file_operations sel_perm_ops = {

	.read		= sel_read_perm,

};



static int sel_make_perm_files(char *objclass, int classvalue,

				struct dentry *dir)

{

	int i, rc = 0, nperms;

	char **perms;



	rc = security_get_permissions(objclass, &perms, &nperms);

	if (rc)

		goto out;



	for (i = 0; i < nperms; i++) {

		struct inode *inode;

		struct dentry *dentry;



		dentry = d_alloc_name(dir, perms[i]);

		if (!dentry) {

			rc = -ENOMEM;

			goto out1;

		}



		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);

		if (!inode) {

			rc = -ENOMEM;

			goto out1;

		}

		inode->i_fop = &sel_perm_ops;

		/* i+1 since perm values are 1-indexed */

		inode->i_ino = sel_perm_to_ino(classvalue, i+1);

		d_add(dentry, inode);

	}



out1:

	for (i = 0; i < nperms; i++)

		kfree(perms[i]);

	kfree(perms);

out:

	return rc;

}



static int sel_make_class_dir_entries(char *classname, int index,

					struct dentry *dir)

{

	struct dentry *dentry = NULL;

	struct inode *inode = NULL;

	int rc;



	dentry = d_alloc_name(dir, "index");

	if (!dentry) {

		rc = -ENOMEM;

		goto out;

	}



	inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);

	if (!inode) {

		rc = -ENOMEM;

		goto out;

	}



	inode->i_fop = &sel_class_ops;

	inode->i_ino = sel_class_to_ino(index);

	d_add(dentry, inode);



	dentry = d_alloc_name(dir, "perms");

	if (!dentry) {

		rc = -ENOMEM;

		goto out;

	}



	rc = sel_make_dir(dir->d_inode, dentry, &last_class_ino);

	if (rc)

		goto out;



	rc = sel_make_perm_files(classname, index, dentry);



out:

	return rc;

}



static void sel_remove_classes(void)

{

	struct list_head *class_node;



	list_for_each(class_node, &class_dir->d_subdirs) {

		struct dentry *class_subdir = list_entry(class_node,

					struct dentry, d_u.d_child);

		struct list_head *class_subdir_node;



		list_for_each(class_subdir_node, &class_subdir->d_subdirs) {

			struct dentry *d = list_entry(class_subdir_node,

						struct dentry, d_u.d_child);



			if (d->d_inode)

				if (d->d_inode->i_mode & S_IFDIR)

					sel_remove_entries(d);

		}



		sel_remove_entries(class_subdir);

	}



	sel_remove_entries(class_dir);

}



static int sel_make_classes(void)

{

	int rc = 0, nclasses, i;

	char **classes;



	/* delete any existing entries */

	sel_remove_classes();



	rc = security_get_classes(&classes, &nclasses);

	if (rc < 0)

		goto out;



	/* +2 since classes are 1-indexed */

	last_class_ino = sel_class_to_ino(nclasses+2);



	for (i = 0; i < nclasses; i++) {

		struct dentry *class_name_dir;



		class_name_dir = d_alloc_name(class_dir, classes[i]);

		if (!class_name_dir) {

			rc = -ENOMEM;

			goto out1;

		}



		rc = sel_make_dir(class_dir->d_inode, class_name_dir,

				&last_class_ino);

		if (rc)

			goto out1;



		/* i+1 since class values are 1-indexed */

		rc = sel_make_class_dir_entries(classes[i], i+1,

				class_name_dir);

		if (rc)

			goto out1;

	}



out1:

	for (i = 0; i < nclasses; i++)

		kfree(classes[i]);

	kfree(classes);

out:

	return rc;

}



static int sel_make_dir(struct inode *dir, struct dentry *dentry,

			unsigned long *ino)

{
@@ -1407,6 +1644,18 @@ static int sel_fill_super(struct super_block * sb, void * data, int silent) 
	if (ret)

		goto err;



	dentry = d_alloc_name(sb->s_root, "class");

	if (!dentry) {

		ret = -ENOMEM;

		goto err;

	}



	ret = sel_make_dir(root_inode, dentry, &sel_last_ino);

	if (ret)

		goto err;



	class_dir = dentry;



out:

	return ret;

err: