smack_lsm.c 67.8 KB
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/*
 *  Simplified MAC Kernel (smack) security module
 *
 *  This file contains the smack hook function implementations.
 *
 *  Author:
 *	Casey Schaufler <casey@schaufler-ca.com>
 *
 *  Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License version 2,
 *      as published by the Free Software Foundation.
 */

#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/ext2_fs.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
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#include <linux/audit.h>
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#include "smack.h"

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#define task_security(task)	(task_cred_xxx((task), security))

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/*
 * I hope these are the hokeyist lines of code in the module. Casey.
 */
#define DEVPTS_SUPER_MAGIC	0x1cd1
#define SOCKFS_MAGIC		0x534F434B
#define TMPFS_MAGIC		0x01021994

/**
 * smk_fetch - Fetch the smack label from a file.
 * @ip: a pointer to the inode
 * @dp: a pointer to the dentry
 *
 * Returns a pointer to the master list entry for the Smack label
 * or NULL if there was no label to fetch.
 */
static char *smk_fetch(struct inode *ip, struct dentry *dp)
{
	int rc;
	char in[SMK_LABELLEN];

	if (ip->i_op->getxattr == NULL)
		return NULL;

	rc = ip->i_op->getxattr(dp, XATTR_NAME_SMACK, in, SMK_LABELLEN);
	if (rc < 0)
		return NULL;

	return smk_import(in, rc);
}

/**
 * new_inode_smack - allocate an inode security blob
 * @smack: a pointer to the Smack label to use in the blob
 *
 * Returns the new blob or NULL if there's no memory available
 */
struct inode_smack *new_inode_smack(char *smack)
{
	struct inode_smack *isp;

	isp = kzalloc(sizeof(struct inode_smack), GFP_KERNEL);
	if (isp == NULL)
		return NULL;

	isp->smk_inode = smack;
	isp->smk_flags = 0;
	mutex_init(&isp->smk_lock);

	return isp;
}

/*
 * LSM hooks.
 * We he, that is fun!
 */

/**
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 * smack_ptrace_may_access - Smack approval on PTRACE_ATTACH
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 * @ctp: child task pointer
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks, and require read and write.
 */
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static int smack_ptrace_may_access(struct task_struct *ctp, unsigned int mode)
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{
	int rc;

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	rc = cap_ptrace_may_access(ctp, mode);
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	if (rc != 0)
		return rc;

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	rc = smk_access(current_security(), task_security(ctp), MAY_READWRITE);
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	if (rc != 0 && capable(CAP_MAC_OVERRIDE))
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		return 0;
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	return rc;
}

/**
 * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
 * @ptp: parent task pointer
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks, and require read and write.
 */
static int smack_ptrace_traceme(struct task_struct *ptp)
{
	int rc;

	rc = cap_ptrace_traceme(ptp);
	if (rc != 0)
		return rc;
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	rc = smk_access(task_security(ptp), current_security(), MAY_READWRITE);
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	if (rc != 0 && has_capability(ptp, CAP_MAC_OVERRIDE))
		return 0;
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	return rc;
}

/**
 * smack_syslog - Smack approval on syslog
 * @type: message type
 *
 * Require that the task has the floor label
 *
 * Returns 0 on success, error code otherwise.
 */
static int smack_syslog(int type)
{
	int rc;
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	char *sp = current_security();
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	rc = cap_syslog(type);
	if (rc != 0)
		return rc;

	if (capable(CAP_MAC_OVERRIDE))
		return 0;

	 if (sp != smack_known_floor.smk_known)
		rc = -EACCES;

	return rc;
}


/*
 * Superblock Hooks.
 */

/**
 * smack_sb_alloc_security - allocate a superblock blob
 * @sb: the superblock getting the blob
 *
 * Returns 0 on success or -ENOMEM on error.
 */
static int smack_sb_alloc_security(struct super_block *sb)
{
	struct superblock_smack *sbsp;

	sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);

	if (sbsp == NULL)
		return -ENOMEM;

	sbsp->smk_root = smack_known_floor.smk_known;
	sbsp->smk_default = smack_known_floor.smk_known;
	sbsp->smk_floor = smack_known_floor.smk_known;
	sbsp->smk_hat = smack_known_hat.smk_known;
	sbsp->smk_initialized = 0;
	spin_lock_init(&sbsp->smk_sblock);

	sb->s_security = sbsp;

	return 0;
}

/**
 * smack_sb_free_security - free a superblock blob
 * @sb: the superblock getting the blob
 *
 */
static void smack_sb_free_security(struct super_block *sb)
{
	kfree(sb->s_security);
	sb->s_security = NULL;
}

/**
 * smack_sb_copy_data - copy mount options data for processing
 * @type: file system type
 * @orig: where to start
 * @smackopts
 *
 * Returns 0 on success or -ENOMEM on error.
 *
 * Copy the Smack specific mount options out of the mount
 * options list.
 */
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static int smack_sb_copy_data(char *orig, char *smackopts)
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{
	char *cp, *commap, *otheropts, *dp;

	otheropts = (char *)get_zeroed_page(GFP_KERNEL);
	if (otheropts == NULL)
		return -ENOMEM;

	for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
		if (strstr(cp, SMK_FSDEFAULT) == cp)
			dp = smackopts;
		else if (strstr(cp, SMK_FSFLOOR) == cp)
			dp = smackopts;
		else if (strstr(cp, SMK_FSHAT) == cp)
			dp = smackopts;
		else if (strstr(cp, SMK_FSROOT) == cp)
			dp = smackopts;
		else
			dp = otheropts;

		commap = strchr(cp, ',');
		if (commap != NULL)
			*commap = '\0';

		if (*dp != '\0')
			strcat(dp, ",");
		strcat(dp, cp);
	}

	strcpy(orig, otheropts);
	free_page((unsigned long)otheropts);

	return 0;
}

/**
 * smack_sb_kern_mount - Smack specific mount processing
 * @sb: the file system superblock
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 * @flags: the mount flags
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 * @data: the smack mount options
 *
 * Returns 0 on success, an error code on failure
 */
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static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
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{
	struct dentry *root = sb->s_root;
	struct inode *inode = root->d_inode;
	struct superblock_smack *sp = sb->s_security;
	struct inode_smack *isp;
	char *op;
	char *commap;
	char *nsp;

	spin_lock(&sp->smk_sblock);
	if (sp->smk_initialized != 0) {
		spin_unlock(&sp->smk_sblock);
		return 0;
	}
	sp->smk_initialized = 1;
	spin_unlock(&sp->smk_sblock);

	for (op = data; op != NULL; op = commap) {
		commap = strchr(op, ',');
		if (commap != NULL)
			*commap++ = '\0';

		if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
			op += strlen(SMK_FSHAT);
			nsp = smk_import(op, 0);
			if (nsp != NULL)
				sp->smk_hat = nsp;
		} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
			op += strlen(SMK_FSFLOOR);
			nsp = smk_import(op, 0);
			if (nsp != NULL)
				sp->smk_floor = nsp;
		} else if (strncmp(op, SMK_FSDEFAULT,
				   strlen(SMK_FSDEFAULT)) == 0) {
			op += strlen(SMK_FSDEFAULT);
			nsp = smk_import(op, 0);
			if (nsp != NULL)
				sp->smk_default = nsp;
		} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
			op += strlen(SMK_FSROOT);
			nsp = smk_import(op, 0);
			if (nsp != NULL)
				sp->smk_root = nsp;
		}
	}

	/*
	 * Initialize the root inode.
	 */
	isp = inode->i_security;
	if (isp == NULL)
		inode->i_security = new_inode_smack(sp->smk_root);
	else
		isp->smk_inode = sp->smk_root;

	return 0;
}

/**
 * smack_sb_statfs - Smack check on statfs
 * @dentry: identifies the file system in question
 *
 * Returns 0 if current can read the floor of the filesystem,
 * and error code otherwise
 */
static int smack_sb_statfs(struct dentry *dentry)
{
	struct superblock_smack *sbp = dentry->d_sb->s_security;

	return smk_curacc(sbp->smk_floor, MAY_READ);
}

/**
 * smack_sb_mount - Smack check for mounting
 * @dev_name: unused
 * @nd: mount point
 * @type: unused
 * @flags: unused
 * @data: unused
 *
 * Returns 0 if current can write the floor of the filesystem
 * being mounted on, an error code otherwise.
 */
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static int smack_sb_mount(char *dev_name, struct path *path,
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			  char *type, unsigned long flags, void *data)
{
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	struct superblock_smack *sbp = path->mnt->mnt_sb->s_security;
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	return smk_curacc(sbp->smk_floor, MAY_WRITE);
}

/**
 * smack_sb_umount - Smack check for unmounting
 * @mnt: file system to unmount
 * @flags: unused
 *
 * Returns 0 if current can write the floor of the filesystem
 * being unmounted, an error code otherwise.
 */
static int smack_sb_umount(struct vfsmount *mnt, int flags)
{
	struct superblock_smack *sbp;

	sbp = mnt->mnt_sb->s_security;

	return smk_curacc(sbp->smk_floor, MAY_WRITE);
}

/*
 * Inode hooks
 */

/**
 * smack_inode_alloc_security - allocate an inode blob
 * @inode - the inode in need of a blob
 *
 * Returns 0 if it gets a blob, -ENOMEM otherwise
 */
static int smack_inode_alloc_security(struct inode *inode)
{
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	inode->i_security = new_inode_smack(current_security());
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	if (inode->i_security == NULL)
		return -ENOMEM;
	return 0;
}

/**
 * smack_inode_free_security - free an inode blob
 * @inode - the inode with a blob
 *
 * Clears the blob pointer in inode
 */
static void smack_inode_free_security(struct inode *inode)
{
	kfree(inode->i_security);
	inode->i_security = NULL;
}

/**
 * smack_inode_init_security - copy out the smack from an inode
 * @inode: the inode
 * @dir: unused
 * @name: where to put the attribute name
 * @value: where to put the attribute value
 * @len: where to put the length of the attribute
 *
 * Returns 0 if it all works out, -ENOMEM if there's no memory
 */
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
				     char **name, void **value, size_t *len)
{
	char *isp = smk_of_inode(inode);

	if (name) {
		*name = kstrdup(XATTR_SMACK_SUFFIX, GFP_KERNEL);
		if (*name == NULL)
			return -ENOMEM;
	}

	if (value) {
		*value = kstrdup(isp, GFP_KERNEL);
		if (*value == NULL)
			return -ENOMEM;
	}

	if (len)
		*len = strlen(isp) + 1;

	return 0;
}

/**
 * smack_inode_link - Smack check on link
 * @old_dentry: the existing object
 * @dir: unused
 * @new_dentry: the new object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
			    struct dentry *new_dentry)
{
	int rc;
	char *isp;

	isp = smk_of_inode(old_dentry->d_inode);
	rc = smk_curacc(isp, MAY_WRITE);

	if (rc == 0 && new_dentry->d_inode != NULL) {
		isp = smk_of_inode(new_dentry->d_inode);
		rc = smk_curacc(isp, MAY_WRITE);
	}

	return rc;
}

/**
 * smack_inode_unlink - Smack check on inode deletion
 * @dir: containing directory object
 * @dentry: file to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the object, error code otherwise
 */
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
{
	struct inode *ip = dentry->d_inode;
	int rc;

	/*
	 * You need write access to the thing you're unlinking
	 */
	rc = smk_curacc(smk_of_inode(ip), MAY_WRITE);
	if (rc == 0)
		/*
		 * You also need write access to the containing directory
		 */
		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE);

	return rc;
}

/**
 * smack_inode_rmdir - Smack check on directory deletion
 * @dir: containing directory object
 * @dentry: directory to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the directory, error code otherwise
 */
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
	int rc;

	/*
	 * You need write access to the thing you're removing
	 */
	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);
	if (rc == 0)
		/*
		 * You also need write access to the containing directory
		 */
		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE);

	return rc;
}

/**
 * smack_inode_rename - Smack check on rename
 * @old_inode: the old directory
 * @old_dentry: unused
 * @new_inode: the new directory
 * @new_dentry: unused
 *
 * Read and write access is required on both the old and
 * new directories.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_rename(struct inode *old_inode,
			      struct dentry *old_dentry,
			      struct inode *new_inode,
			      struct dentry *new_dentry)
{
	int rc;
	char *isp;

	isp = smk_of_inode(old_dentry->d_inode);
	rc = smk_curacc(isp, MAY_READWRITE);

	if (rc == 0 && new_dentry->d_inode != NULL) {
		isp = smk_of_inode(new_dentry->d_inode);
		rc = smk_curacc(isp, MAY_READWRITE);
	}

	return rc;
}

/**
 * smack_inode_permission - Smack version of permission()
 * @inode: the inode in question
 * @mask: the access requested
 * @nd: unused
 *
 * This is the important Smack hook.
 *
 * Returns 0 if access is permitted, -EACCES otherwise
 */
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static int smack_inode_permission(struct inode *inode, int mask)
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{
	/*
	 * No permission to check. Existence test. Yup, it's there.
	 */
	if (mask == 0)
		return 0;

	return smk_curacc(smk_of_inode(inode), mask);
}

/**
 * smack_inode_setattr - Smack check for setting attributes
 * @dentry: the object
 * @iattr: for the force flag
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
	/*
	 * Need to allow for clearing the setuid bit.
	 */
	if (iattr->ia_valid & ATTR_FORCE)
		return 0;

	return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);
}

/**
 * smack_inode_getattr - Smack check for getting attributes
 * @mnt: unused
 * @dentry: the object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
	return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ);
}

/**
 * smack_inode_setxattr - Smack check for setting xattrs
 * @dentry: the object
 * @name: name of the attribute
 * @value: unused
 * @size: unused
 * @flags: unused
 *
 * This protects the Smack attribute explicitly.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
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static int smack_inode_setxattr(struct dentry *dentry, const char *name,
				const void *value, size_t size, int flags)
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{
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	int rc = 0;
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	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
		if (!capable(CAP_MAC_ADMIN))
			rc = -EPERM;
	} else
		rc = cap_inode_setxattr(dentry, name, value, size, flags);

	if (rc == 0)
		rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);

	return rc;
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}

/**
 * smack_inode_post_setxattr - Apply the Smack update approved above
 * @dentry: object
 * @name: attribute name
 * @value: attribute value
 * @size: attribute size
 * @flags: unused
 *
 * Set the pointer in the inode blob to the entry found
 * in the master label list.
 */
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static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
				      const void *value, size_t size, int flags)
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{
	struct inode_smack *isp;
	char *nsp;

	/*
	 * Not SMACK
	 */
	if (strcmp(name, XATTR_NAME_SMACK))
		return;

	if (size >= SMK_LABELLEN)
		return;

	isp = dentry->d_inode->i_security;

	/*
	 * No locking is done here. This is a pointer
	 * assignment.
	 */
	nsp = smk_import(value, size);
	if (nsp != NULL)
		isp->smk_inode = nsp;
	else
		isp->smk_inode = smack_known_invalid.smk_known;

	return;
}

/*
 * smack_inode_getxattr - Smack check on getxattr
 * @dentry: the object
 * @name: unused
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
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static int smack_inode_getxattr(struct dentry *dentry, const char *name)
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{
	return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ);
}

/*
 * smack_inode_removexattr - Smack check on removexattr
 * @dentry: the object
 * @name: name of the attribute
 *
 * Removing the Smack attribute requires CAP_MAC_ADMIN
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
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static int smack_inode_removexattr(struct dentry *dentry, const char *name)
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{
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	int rc = 0;
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	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
		if (!capable(CAP_MAC_ADMIN))
			rc = -EPERM;
	} else
		rc = cap_inode_removexattr(dentry, name);

	if (rc == 0)
		rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE);

	return rc;
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}

/**
 * smack_inode_getsecurity - get smack xattrs
 * @inode: the object
 * @name: attribute name
 * @buffer: where to put the result
 * @size: size of the buffer
 * @err: unused
 *
 * Returns the size of the attribute or an error code
 */
static int smack_inode_getsecurity(const struct inode *inode,
				   const char *name, void **buffer,
				   bool alloc)
{
	struct socket_smack *ssp;
	struct socket *sock;
	struct super_block *sbp;
	struct inode *ip = (struct inode *)inode;
	char *isp;
	int ilen;
	int rc = 0;

	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
		isp = smk_of_inode(inode);
		ilen = strlen(isp) + 1;
		*buffer = isp;
		return ilen;
	}

	/*
	 * The rest of the Smack xattrs are only on sockets.
	 */
	sbp = ip->i_sb;
	if (sbp->s_magic != SOCKFS_MAGIC)
		return -EOPNOTSUPP;

	sock = SOCKET_I(ip);
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	if (sock == NULL || sock->sk == NULL)
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		return -EOPNOTSUPP;

	ssp = sock->sk->sk_security;

	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
		isp = ssp->smk_in;
	else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
		isp = ssp->smk_out;
	else
		return -EOPNOTSUPP;

	ilen = strlen(isp) + 1;
	if (rc == 0) {
		*buffer = isp;
		rc = ilen;
	}

	return rc;
}


/**
 * smack_inode_listsecurity - list the Smack attributes
 * @inode: the object
 * @buffer: where they go
 * @buffer_size: size of buffer
 *
 * Returns 0 on success, -EINVAL otherwise
 */
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
				    size_t buffer_size)
{
	int len = strlen(XATTR_NAME_SMACK);

	if (buffer != NULL && len <= buffer_size) {
		memcpy(buffer, XATTR_NAME_SMACK, len);
		return len;
	}
	return -EINVAL;
}

778 779 780 781 782 783 784 785 786 787 788 789
/**
 * smack_inode_getsecid - Extract inode's security id
 * @inode: inode to extract the info from
 * @secid: where result will be saved
 */
static void smack_inode_getsecid(const struct inode *inode, u32 *secid)
{
	struct inode_smack *isp = inode->i_security;

	*secid = smack_to_secid(isp->smk_inode);
}

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/*
 * File Hooks
 */

/**
 * smack_file_permission - Smack check on file operations
 * @file: unused
 * @mask: unused
 *
 * Returns 0
 *
 * Should access checks be done on each read or write?
 * UNICOS and SELinux say yes.
 * Trusted Solaris, Trusted Irix, and just about everyone else says no.
 *
 * I'll say no for now. Smack does not do the frequent
 * label changing that SELinux does.
 */
static int smack_file_permission(struct file *file, int mask)
{
	return 0;
}

/**
 * smack_file_alloc_security - assign a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no allocation is done.
 *
 * Returns 0
 */
static int smack_file_alloc_security(struct file *file)
{
824
	file->f_security = current_security();
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	return 0;
}

/**
 * smack_file_free_security - clear a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no memory is freed.
 */
static void smack_file_free_security(struct file *file)
{
	file->f_security = NULL;
}

/**
 * smack_file_ioctl - Smack check on ioctls
 * @file: the object
 * @cmd: what to do
 * @arg: unused
 *
 * Relies heavily on the correct use of the ioctl command conventions.
 *
 * Returns 0 if allowed, error code otherwise
 */
static int smack_file_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	int rc = 0;

	if (_IOC_DIR(cmd) & _IOC_WRITE)
		rc = smk_curacc(file->f_security, MAY_WRITE);

	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
		rc = smk_curacc(file->f_security, MAY_READ);

	return rc;
}

/**
 * smack_file_lock - Smack check on file locking
 * @file: the object
 * @cmd unused
 *
 * Returns 0 if current has write access, error code otherwise
 */
static int smack_file_lock(struct file *file, unsigned int cmd)
{
	return smk_curacc(file->f_security, MAY_WRITE);
}

/**
 * smack_file_fcntl - Smack check on fcntl
 * @file: the object
 * @cmd: what action to check
 * @arg: unused
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_fcntl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	int rc;

	switch (cmd) {
	case F_DUPFD:
	case F_GETFD:
	case F_GETFL:
	case F_GETLK:
	case F_GETOWN:
	case F_GETSIG:
		rc = smk_curacc(file->f_security, MAY_READ);
		break;
	case F_SETFD:
	case F_SETFL:
	case F_SETLK:
	case F_SETLKW:
	case F_SETOWN:
	case F_SETSIG:
		rc = smk_curacc(file->f_security, MAY_WRITE);
		break;
	default:
		rc = smk_curacc(file->f_security, MAY_READWRITE);
	}

	return rc;
}

/**
 * smack_file_set_fowner - set the file security blob value
 * @file: object in question
 *
 * Returns 0
 * Further research may be required on this one.
 */
static int smack_file_set_fowner(struct file *file)
{
922
	file->f_security = current_security();
923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946
	return 0;
}

/**
 * smack_file_send_sigiotask - Smack on sigio
 * @tsk: The target task
 * @fown: the object the signal come from
 * @signum: unused
 *
 * Allow a privileged task to get signals even if it shouldn't
 *
 * Returns 0 if a subject with the object's smack could
 * write to the task, an error code otherwise.
 */
static int smack_file_send_sigiotask(struct task_struct *tsk,
				     struct fown_struct *fown, int signum)
{
	struct file *file;
	int rc;

	/*
	 * struct fown_struct is never outside the context of a struct file
	 */
	file = container_of(fown, struct file, f_owner);
947
	rc = smk_access(file->f_security, tsk->cred->security, MAY_WRITE);
948
	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978
		return 0;
	return rc;
}

/**
 * smack_file_receive - Smack file receive check
 * @file: the object
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_receive(struct file *file)
{
	int may = 0;

	/*
	 * This code relies on bitmasks.
	 */
	if (file->f_mode & FMODE_READ)
		may = MAY_READ;
	if (file->f_mode & FMODE_WRITE)
		may |= MAY_WRITE;

	return smk_curacc(file->f_security, may);
}

/*
 * Task hooks
 */

/**
979 980
 * smack_cred_free - "free" task-level security credentials
 * @cred: the credentials in question
981 982 983 984 985
 *
 * Smack isn't using copies of blobs. Everyone
 * points to an immutable list. The blobs never go away.
 * There is no leak here.
 */
986
static void smack_cred_free(struct cred *cred)
987
{
988
	cred->security = NULL;
989 990
}

D
David Howells 已提交
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/**
 * smack_cred_prepare - prepare new set of credentials for modification
 * @new: the new credentials
 * @old: the original credentials
 * @gfp: the atomicity of any memory allocations
 *
 * Prepare a new set of credentials for modification.
 */
static int smack_cred_prepare(struct cred *new, const struct cred *old,
			      gfp_t gfp)
{
	new->security = old->security;
	return 0;
}

/*
 * commit new credentials
 * @new: the new credentials
 * @old: the original credentials
 */
static void smack_cred_commit(struct cred *new, const struct cred *old)
{
}

1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049
/**
 * smack_kernel_act_as - Set the subjective context in a set of credentials
 * @new points to the set of credentials to be modified.
 * @secid specifies the security ID to be set
 *
 * Set the security data for a kernel service.
 */
static int smack_kernel_act_as(struct cred *new, u32 secid)
{
	char *smack = smack_from_secid(secid);

	if (smack == NULL)
		return -EINVAL;

	new->security = smack;
	return 0;
}

/**
 * smack_kernel_create_files_as - Set the file creation label in a set of creds
 * @new points to the set of credentials to be modified
 * @inode points to the inode to use as a reference
 *
 * Set the file creation context in a set of credentials to the same
 * as the objective context of the specified inode
 */
static int smack_kernel_create_files_as(struct cred *new,
					struct inode *inode)
{
	struct inode_smack *isp = inode->i_security;

	new->security = isp->smk_inode;
	return 0;
}

1050 1051 1052 1053 1054 1055 1056 1057 1058
/**
 * smack_task_setpgid - Smack check on setting pgid
 * @p: the task object
 * @pgid: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
1059
	return smk_curacc(task_security(p), MAY_WRITE);
1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
}

/**
 * smack_task_getpgid - Smack access check for getpgid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getpgid(struct task_struct *p)
{
1070
	return smk_curacc(task_security(p), MAY_READ);
1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
}

/**
 * smack_task_getsid - Smack access check for getsid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getsid(struct task_struct *p)
{
1081
	return smk_curacc(task_security(p), MAY_READ);
1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092
}

/**
 * smack_task_getsecid - get the secid of the task
 * @p: the object task
 * @secid: where to put the result
 *
 * Sets the secid to contain a u32 version of the smack label.
 */
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
{
1093
	*secid = smack_to_secid(task_security(p));
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}

/**
 * smack_task_setnice - Smack check on setting nice
 * @p: the task object
 * @nice: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setnice(struct task_struct *p, int nice)
{
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	int rc;

	rc = cap_task_setnice(p, nice);
	if (rc == 0)
1109
		rc = smk_curacc(task_security(p), MAY_WRITE);
1110
	return rc;
1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
}

/**
 * smack_task_setioprio - Smack check on setting ioprio
 * @p: the task object
 * @ioprio: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setioprio(struct task_struct *p, int ioprio)
{
1122 1123 1124 1125
	int rc;

	rc = cap_task_setioprio(p, ioprio);
	if (rc == 0)
1126
		rc = smk_curacc(task_security(p), MAY_WRITE);
1127
	return rc;
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}

/**
 * smack_task_getioprio - Smack check on reading ioprio
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getioprio(struct task_struct *p)
{
1138
	return smk_curacc(task_security(p), MAY_READ);
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}

/**
 * smack_task_setscheduler - Smack check on setting scheduler
 * @p: the task object
 * @policy: unused
 * @lp: unused
 *
 * Return 0 if read access is permitted
 */
static int smack_task_setscheduler(struct task_struct *p, int policy,
				   struct sched_param *lp)
{
1152 1153 1154 1155
	int rc;

	rc = cap_task_setscheduler(p, policy, lp);
	if (rc == 0)
1156
		rc = smk_curacc(task_security(p), MAY_WRITE);
1157
	return rc;
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}

/**
 * smack_task_getscheduler - Smack check on reading scheduler
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getscheduler(struct task_struct *p)
{
1168
	return smk_curacc(task_security(p), MAY_READ);
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}

/**
 * smack_task_movememory - Smack check on moving memory
 * @p: the task object
 *
 * Return 0 if write access is permitted
 */
static int smack_task_movememory(struct task_struct *p)
{
1179
	return smk_curacc(task_security(p), MAY_WRITE);
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}

/**
 * smack_task_kill - Smack check on signal delivery
 * @p: the task object
 * @info: unused
 * @sig: unused
 * @secid: identifies the smack to use in lieu of current's
 *
 * Return 0 if write access is permitted
 *
 * The secid behavior is an artifact of an SELinux hack
 * in the USB code. Someday it may go away.
 */
static int smack_task_kill(struct task_struct *p, struct siginfo *info,
			   int sig, u32 secid)
{
	/*
	 * Sending a signal requires that the sender
	 * can write the receiver.
	 */
	if (secid == 0)
1202
		return smk_curacc(task_security(p), MAY_WRITE);
1203 1204 1205 1206 1207
	/*
	 * If the secid isn't 0 we're dealing with some USB IO
	 * specific behavior. This is not clean. For one thing
	 * we can't take privilege into account.
	 */
1208
	return smk_access(smack_from_secid(secid), task_security(p), MAY_WRITE);
1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220
}

/**
 * smack_task_wait - Smack access check for waiting
 * @p: task to wait for
 *
 * Returns 0 if current can wait for p, error code otherwise
 */
static int smack_task_wait(struct task_struct *p)
{
	int rc;

1221
	rc = smk_access(current_security(), task_security(p), MAY_WRITE);
1222 1223 1224 1225 1226 1227 1228 1229 1230
	if (rc == 0)
		return 0;

	/*
	 * Allow the operation to succeed if either task
	 * has privilege to perform operations that might
	 * account for the smack labels having gotten to
	 * be different in the first place.
	 *
1231
	 * This breaks the strict subject/object access
1232 1233 1234 1235
	 * control ideal, taking the object's privilege
	 * state into account in the decision as well as
	 * the smack value.
	 */
1236
	if (capable(CAP_MAC_OVERRIDE) || has_capability(p, CAP_MAC_OVERRIDE))
1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251
		return 0;

	return rc;
}

/**
 * smack_task_to_inode - copy task smack into the inode blob
 * @p: task to copy from
 * inode: inode to copy to
 *
 * Sets the smack pointer in the inode security blob
 */
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
	struct inode_smack *isp = inode->i_security;
1252
	isp->smk_inode = task_security(p);
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270
}

/*
 * Socket hooks.
 */

/**
 * smack_sk_alloc_security - Allocate a socket blob
 * @sk: the socket
 * @family: unused
 * @priority: memory allocation priority
 *
 * Assign Smack pointers to current
 *
 * Returns 0 on success, -ENOMEM is there's no memory
 */
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
{
1271
	char *csp = current_security();
1272 1273 1274 1275 1276 1277 1278 1279
	struct socket_smack *ssp;

	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
	if (ssp == NULL)
		return -ENOMEM;

	ssp->smk_in = csp;
	ssp->smk_out = csp;
1280
	ssp->smk_labeled = SMACK_CIPSO_SOCKET;
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313
	ssp->smk_packet[0] = '\0';

	sk->sk_security = ssp;

	return 0;
}

/**
 * smack_sk_free_security - Free a socket blob
 * @sk: the socket
 *
 * Clears the blob pointer
 */
static void smack_sk_free_security(struct sock *sk)
{
	kfree(sk->sk_security);
}

/**
 * smack_set_catset - convert a capset to netlabel mls categories
 * @catset: the Smack categories
 * @sap: where to put the netlabel categories
 *
 * Allocates and fills attr.mls.cat
 */
static void smack_set_catset(char *catset, struct netlbl_lsm_secattr *sap)
{
	unsigned char *cp;
	unsigned char m;
	int cat;
	int rc;
	int byte;

1314
	if (!catset)
1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344
		return;

	sap->flags |= NETLBL_SECATTR_MLS_CAT;
	sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
	sap->attr.mls.cat->startbit = 0;

	for (cat = 1, cp = catset, byte = 0; byte < SMK_LABELLEN; cp++, byte++)
		for (m = 0x80; m != 0; m >>= 1, cat++) {
			if ((m & *cp) == 0)
				continue;
			rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
							  cat, GFP_ATOMIC);
		}
}

/**
 * smack_to_secattr - fill a secattr from a smack value
 * @smack: the smack value
 * @nlsp: where the result goes
 *
 * Casey says that CIPSO is good enough for now.
 * It can be used to effect.
 * It can also be abused to effect when necessary.
 * Appologies to the TSIG group in general and GW in particular.
 */
static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
{
	struct smack_cipso cipso;
	int rc;

1345 1346
	nlsp->domain = smack;
	nlsp->flags = NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
1347

1348 1349 1350 1351 1352 1353 1354
	rc = smack_to_cipso(smack, &cipso);
	if (rc == 0) {
		nlsp->attr.mls.lvl = cipso.smk_level;
		smack_set_catset(cipso.smk_catset, nlsp);
	} else {
		nlsp->attr.mls.lvl = smack_cipso_direct;
		smack_set_catset(smack, nlsp);
1355 1356 1357 1358 1359 1360
	}
}

/**
 * smack_netlabel - Set the secattr on a socket
 * @sk: the socket
1361
 * @labeled: socket label scheme
1362 1363 1364 1365 1366 1367
 *
 * Convert the outbound smack value (smk_out) to a
 * secattr and attach it to the socket.
 *
 * Returns 0 on success or an error code
 */
1368
static int smack_netlabel(struct sock *sk, int labeled)
1369
{
1370
	struct socket_smack *ssp;
1371
	struct netlbl_lsm_secattr secattr;
1372
	int rc = 0;
1373

1374
	ssp = sk->sk_security;
1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407
	/*
	 * Usually the netlabel code will handle changing the
	 * packet labeling based on the label.
	 * The case of a single label host is different, because
	 * a single label host should never get a labeled packet
	 * even though the label is usually associated with a packet
	 * label.
	 */
	local_bh_disable();
	bh_lock_sock_nested(sk);

	if (ssp->smk_out == smack_net_ambient ||
	    labeled == SMACK_UNLABELED_SOCKET)
		netlbl_sock_delattr(sk);
	else {
		netlbl_secattr_init(&secattr);
		smack_to_secattr(ssp->smk_out, &secattr);
		rc = netlbl_sock_setattr(sk, &secattr);
		netlbl_secattr_destroy(&secattr);
	}

	bh_unlock_sock(sk);
	local_bh_enable();
	/*
	 * Remember the label scheme used so that it is not
	 * necessary to do the netlabel setting if it has not
	 * changed the next time through.
	 *
	 * The -EDESTADDRREQ case is an indication that there's
	 * a single level host involved.
	 */
	if (rc == 0)
		ssp->smk_labeled = labeled;
1408

1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
	return rc;
}

/**
 * smack_inode_setsecurity - set smack xattrs
 * @inode: the object
 * @name: attribute name
 * @value: attribute value
 * @size: size of the attribute
 * @flags: unused
 *
 * Sets the named attribute in the appropriate blob
 *
 * Returns 0 on success, or an error code
 */
static int smack_inode_setsecurity(struct inode *inode, const char *name,
				   const void *value, size_t size, int flags)
{
	char *sp;
	struct inode_smack *nsp = inode->i_security;
	struct socket_smack *ssp;
	struct socket *sock;
1431
	int rc = 0;
1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450

	if (value == NULL || size > SMK_LABELLEN)
		return -EACCES;

	sp = smk_import(value, size);
	if (sp == NULL)
		return -EINVAL;

	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
		nsp->smk_inode = sp;
		return 0;
	}
	/*
	 * The rest of the Smack xattrs are only on sockets.
	 */
	if (inode->i_sb->s_magic != SOCKFS_MAGIC)
		return -EOPNOTSUPP;

	sock = SOCKET_I(inode);
1451
	if (sock == NULL || sock->sk == NULL)
1452 1453 1454 1455 1456 1457 1458 1459
		return -EOPNOTSUPP;

	ssp = sock->sk->sk_security;

	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
		ssp->smk_in = sp;
	else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
		ssp->smk_out = sp;
1460
		rc = smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
1461 1462 1463
		if (rc != 0)
			printk(KERN_WARNING "Smack: \"%s\" netlbl error %d.\n",
			       __func__, -rc);
1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484
	} else
		return -EOPNOTSUPP;

	return 0;
}

/**
 * smack_socket_post_create - finish socket setup
 * @sock: the socket
 * @family: protocol family
 * @type: unused
 * @protocol: unused
 * @kern: unused
 *
 * Sets the netlabel information on the socket
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_post_create(struct socket *sock, int family,
				    int type, int protocol, int kern)
{
1485
	if (family != PF_INET || sock->sk == NULL)
1486 1487 1488 1489
		return 0;
	/*
	 * Set the outbound netlbl.
	 */
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
	return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
}


/**
 * smack_host_label - check host based restrictions
 * @sip: the object end
 *
 * looks for host based access restrictions
 *
 * This version will only be appropriate for really small
 * sets of single label hosts. Because of the masking
 * it cannot shortcut out on the first match. There are
 * numerious ways to address the problem, but none of them
 * have been applied here.
 *
 * Returns the label of the far end or NULL if it's not special.
 */
static char *smack_host_label(struct sockaddr_in *sip)
{
	struct smk_netlbladdr *snp;
	char *bestlabel = NULL;
	struct in_addr *siap = &sip->sin_addr;
	struct in_addr *liap;
	struct in_addr *miap;
	struct in_addr bestmask;

	if (siap->s_addr == 0)
		return NULL;

	bestmask.s_addr = 0;

	for (snp = smack_netlbladdrs; snp != NULL; snp = snp->smk_next) {
		liap = &snp->smk_host.sin_addr;
		miap = &snp->smk_mask;
		/*
		 * If the addresses match after applying the list entry mask
		 * the entry matches the address. If it doesn't move along to
		 * the next entry.
		 */
		if ((liap->s_addr & miap->s_addr) !=
		    (siap->s_addr & miap->s_addr))
			continue;
		/*
		 * If the list entry mask identifies a single address
		 * it can't get any more specific.
		 */
		if (miap->s_addr == 0xffffffff)
			return snp->smk_label;
		/*
		 * If the list entry mask is less specific than the best
		 * already found this entry is uninteresting.
		 */
		if ((miap->s_addr | bestmask.s_addr) == bestmask.s_addr)
			continue;
		/*
		 * This is better than any entry found so far.
		 */
		bestmask.s_addr = miap->s_addr;
		bestlabel = snp->smk_label;
	}

	return bestlabel;
}

/**
 * smack_socket_connect - connect access check
 * @sock: the socket
 * @sap: the other end
 * @addrlen: size of sap
 *
 * Verifies that a connection may be possible
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
				int addrlen)
{
	struct socket_smack *ssp = sock->sk->sk_security;
	char *hostsp;
	int rc;

	if (sock->sk == NULL || sock->sk->sk_family != PF_INET)
		return 0;

	if (addrlen < sizeof(struct sockaddr_in))
		return -EINVAL;

	hostsp = smack_host_label((struct sockaddr_in *)sap);
	if (hostsp == NULL) {
		if (ssp->smk_labeled != SMACK_CIPSO_SOCKET)
			return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
		return 0;
	}

	rc = smk_access(ssp->smk_out, hostsp, MAY_WRITE);
	if (rc != 0)
		return rc;

	if (ssp->smk_labeled != SMACK_UNLABELED_SOCKET)
		return smack_netlabel(sock->sk, SMACK_UNLABELED_SOCKET);
	return 0;
1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621
}

/**
 * smack_flags_to_may - convert S_ to MAY_ values
 * @flags: the S_ value
 *
 * Returns the equivalent MAY_ value
 */
static int smack_flags_to_may(int flags)
{
	int may = 0;

	if (flags & S_IRUGO)
		may |= MAY_READ;
	if (flags & S_IWUGO)
		may |= MAY_WRITE;
	if (flags & S_IXUGO)
		may |= MAY_EXEC;

	return may;
}

/**
 * smack_msg_msg_alloc_security - Set the security blob for msg_msg
 * @msg: the object
 *
 * Returns 0
 */
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
{
1622
	msg->security = current_security();
1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657
	return 0;
}

/**
 * smack_msg_msg_free_security - Clear the security blob for msg_msg
 * @msg: the object
 *
 * Clears the blob pointer
 */
static void smack_msg_msg_free_security(struct msg_msg *msg)
{
	msg->security = NULL;
}

/**
 * smack_of_shm - the smack pointer for the shm
 * @shp: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_shm(struct shmid_kernel *shp)
{
	return (char *)shp->shm_perm.security;
}

/**
 * smack_shm_alloc_security - Set the security blob for shm
 * @shp: the object
 *
 * Returns 0
 */
static int smack_shm_alloc_security(struct shmid_kernel *shp)
{
	struct kern_ipc_perm *isp = &shp->shm_perm;

1658
	isp->security = current_security();
1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699
	return 0;
}

/**
 * smack_shm_free_security - Clear the security blob for shm
 * @shp: the object
 *
 * Clears the blob pointer
 */
static void smack_shm_free_security(struct shmid_kernel *shp)
{
	struct kern_ipc_perm *isp = &shp->shm_perm;

	isp->security = NULL;
}

/**
 * smack_shm_associate - Smack access check for shm
 * @shp: the object
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_associate(struct shmid_kernel *shp, int shmflg)
{
	char *ssp = smack_of_shm(shp);
	int may;

	may = smack_flags_to_may(shmflg);
	return smk_curacc(ssp, may);
}

/**
 * smack_shm_shmctl - Smack access check for shm
 * @shp: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd)
{
1700
	char *ssp;
1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723
	int may;

	switch (cmd) {
	case IPC_STAT:
	case SHM_STAT:
		may = MAY_READ;
		break;
	case IPC_SET:
	case SHM_LOCK:
	case SHM_UNLOCK:
	case IPC_RMID:
		may = MAY_READWRITE;
		break;
	case IPC_INFO:
	case SHM_INFO:
		/*
		 * System level information.
		 */
		return 0;
	default:
		return -EINVAL;
	}

1724
	ssp = smack_of_shm(shp);
1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766
	return smk_curacc(ssp, may);
}

/**
 * smack_shm_shmat - Smack access for shmat
 * @shp: the object
 * @shmaddr: unused
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
			   int shmflg)
{
	char *ssp = smack_of_shm(shp);
	int may;

	may = smack_flags_to_may(shmflg);
	return smk_curacc(ssp, may);
}

/**
 * smack_of_sem - the smack pointer for the sem
 * @sma: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_sem(struct sem_array *sma)
{
	return (char *)sma->sem_perm.security;
}

/**
 * smack_sem_alloc_security - Set the security blob for sem
 * @sma: the object
 *
 * Returns 0
 */
static int smack_sem_alloc_security(struct sem_array *sma)
{
	struct kern_ipc_perm *isp = &sma->sem_perm;

1767
	isp->security = current_security();
1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808
	return 0;
}

/**
 * smack_sem_free_security - Clear the security blob for sem
 * @sma: the object
 *
 * Clears the blob pointer
 */
static void smack_sem_free_security(struct sem_array *sma)
{
	struct kern_ipc_perm *isp = &sma->sem_perm;

	isp->security = NULL;
}

/**
 * smack_sem_associate - Smack access check for sem
 * @sma: the object
 * @semflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_associate(struct sem_array *sma, int semflg)
{
	char *ssp = smack_of_sem(sma);
	int may;

	may = smack_flags_to_may(semflg);
	return smk_curacc(ssp, may);
}

/**
 * smack_sem_shmctl - Smack access check for sem
 * @sma: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_semctl(struct sem_array *sma, int cmd)
{
1809
	char *ssp;
1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837
	int may;

	switch (cmd) {
	case GETPID:
	case GETNCNT:
	case GETZCNT:
	case GETVAL:
	case GETALL:
	case IPC_STAT:
	case SEM_STAT:
		may = MAY_READ;
		break;
	case SETVAL:
	case SETALL:
	case IPC_RMID:
	case IPC_SET:
		may = MAY_READWRITE;
		break;
	case IPC_INFO:
	case SEM_INFO:
		/*
		 * System level information
		 */
		return 0;
	default:
		return -EINVAL;
	}

1838
	ssp = smack_of_sem(sma);
1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870
	return smk_curacc(ssp, may);
}

/**
 * smack_sem_semop - Smack checks of semaphore operations
 * @sma: the object
 * @sops: unused
 * @nsops: unused
 * @alter: unused
 *
 * Treated as read and write in all cases.
 *
 * Returns 0 if access is allowed, error code otherwise
 */
static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
			   unsigned nsops, int alter)
{
	char *ssp = smack_of_sem(sma);

	return smk_curacc(ssp, MAY_READWRITE);
}

/**
 * smack_msg_alloc_security - Set the security blob for msg
 * @msq: the object
 *
 * Returns 0
 */
static int smack_msg_queue_alloc_security(struct msg_queue *msq)
{
	struct kern_ipc_perm *kisp = &msq->q_perm;

1871
	kisp->security = current_security();
1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923
	return 0;
}

/**
 * smack_msg_free_security - Clear the security blob for msg
 * @msq: the object
 *
 * Clears the blob pointer
 */
static void smack_msg_queue_free_security(struct msg_queue *msq)
{
	struct kern_ipc_perm *kisp = &msq->q_perm;

	kisp->security = NULL;
}

/**
 * smack_of_msq - the smack pointer for the msq
 * @msq: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_msq(struct msg_queue *msq)
{
	return (char *)msq->q_perm.security;
}

/**
 * smack_msg_queue_associate - Smack access check for msg_queue
 * @msq: the object
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg)
{
	char *msp = smack_of_msq(msq);
	int may;

	may = smack_flags_to_may(msqflg);
	return smk_curacc(msp, may);
}

/**
 * smack_msg_queue_msgctl - Smack access check for msg_queue
 * @msq: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
{
1924
	char *msp;
1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945
	int may;

	switch (cmd) {
	case IPC_STAT:
	case MSG_STAT:
		may = MAY_READ;
		break;
	case IPC_SET:
	case IPC_RMID:
		may = MAY_READWRITE;
		break;
	case IPC_INFO:
	case MSG_INFO:
		/*
		 * System level information
		 */
		return 0;
	default:
		return -EINVAL;
	}

1946
	msp = smack_of_msq(msq);
1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
	return smk_curacc(msp, may);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @msq: the object
 * @msg: unused
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg,
				  int msqflg)
{
	char *msp = smack_of_msq(msq);
	int rc;

	rc = smack_flags_to_may(msqflg);
	return smk_curacc(msp, rc);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @msq: the object
 * @msg: unused
 * @target: unused
 * @type: unused
 * @mode: unused
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
			struct task_struct *target, long type, int mode)
{
	char *msp = smack_of_msq(msq);

	return smk_curacc(msp, MAY_READWRITE);
}

/**
 * smack_ipc_permission - Smack access for ipc_permission()
 * @ipp: the object permissions
 * @flag: access requested
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
{
	char *isp = ipp->security;
	int may;

	may = smack_flags_to_may(flag);
	return smk_curacc(isp, may);
}

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
/**
 * smack_ipc_getsecid - Extract smack security id
 * @ipcp: the object permissions
 * @secid: where result will be saved
 */
static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
{
	char *smack = ipp->security;

	*secid = smack_to_secid(smack);
}

2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025
/**
 * smack_d_instantiate - Make sure the blob is correct on an inode
 * @opt_dentry: unused
 * @inode: the object
 *
 * Set the inode's security blob if it hasn't been done already.
 */
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
{
	struct super_block *sbp;
	struct superblock_smack *sbsp;
	struct inode_smack *isp;
2026
	char *csp = current_security();
2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051
	char *fetched;
	char *final;
	struct dentry *dp;

	if (inode == NULL)
		return;

	isp = inode->i_security;

	mutex_lock(&isp->smk_lock);
	/*
	 * If the inode is already instantiated
	 * take the quick way out
	 */
	if (isp->smk_flags & SMK_INODE_INSTANT)
		goto unlockandout;

	sbp = inode->i_sb;
	sbsp = sbp->s_security;
	/*
	 * We're going to use the superblock default label
	 * if there's no label on the file.
	 */
	final = sbsp->smk_default;

C
Casey Schaufler 已提交
2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063
	/*
	 * If this is the root inode the superblock
	 * may be in the process of initialization.
	 * If that is the case use the root value out
	 * of the superblock.
	 */
	if (opt_dentry->d_parent == opt_dentry) {
		isp->smk_inode = sbsp->smk_root;
		isp->smk_flags |= SMK_INODE_INSTANT;
		goto unlockandout;
	}

2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182
	/*
	 * This is pretty hackish.
	 * Casey says that we shouldn't have to do
	 * file system specific code, but it does help
	 * with keeping it simple.
	 */
	switch (sbp->s_magic) {
	case SMACK_MAGIC:
		/*
		 * Casey says that it's a little embarassing
		 * that the smack file system doesn't do
		 * extended attributes.
		 */
		final = smack_known_star.smk_known;
		break;
	case PIPEFS_MAGIC:
		/*
		 * Casey says pipes are easy (?)
		 */
		final = smack_known_star.smk_known;
		break;
	case DEVPTS_SUPER_MAGIC:
		/*
		 * devpts seems content with the label of the task.
		 * Programs that change smack have to treat the
		 * pty with respect.
		 */
		final = csp;
		break;
	case SOCKFS_MAGIC:
		/*
		 * Casey says sockets get the smack of the task.
		 */
		final = csp;
		break;
	case PROC_SUPER_MAGIC:
		/*
		 * Casey says procfs appears not to care.
		 * The superblock default suffices.
		 */
		break;
	case TMPFS_MAGIC:
		/*
		 * Device labels should come from the filesystem,
		 * but watch out, because they're volitile,
		 * getting recreated on every reboot.
		 */
		final = smack_known_star.smk_known;
		/*
		 * No break.
		 *
		 * If a smack value has been set we want to use it,
		 * but since tmpfs isn't giving us the opportunity
		 * to set mount options simulate setting the
		 * superblock default.
		 */
	default:
		/*
		 * This isn't an understood special case.
		 * Get the value from the xattr.
		 *
		 * No xattr support means, alas, no SMACK label.
		 * Use the aforeapplied default.
		 * It would be curious if the label of the task
		 * does not match that assigned.
		 */
		if (inode->i_op->getxattr == NULL)
			break;
		/*
		 * Get the dentry for xattr.
		 */
		if (opt_dentry == NULL) {
			dp = d_find_alias(inode);
			if (dp == NULL)
				break;
		} else {
			dp = dget(opt_dentry);
			if (dp == NULL)
				break;
		}

		fetched = smk_fetch(inode, dp);
		if (fetched != NULL)
			final = fetched;

		dput(dp);
		break;
	}

	if (final == NULL)
		isp->smk_inode = csp;
	else
		isp->smk_inode = final;

	isp->smk_flags |= SMK_INODE_INSTANT;

unlockandout:
	mutex_unlock(&isp->smk_lock);
	return;
}

/**
 * smack_getprocattr - Smack process attribute access
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: where to put the result
 *
 * Places a copy of the task Smack into value
 *
 * Returns the length of the smack label or an error code
 */
static int smack_getprocattr(struct task_struct *p, char *name, char **value)
{
	char *cp;
	int slen;

	if (strcmp(name, "current") != 0)
		return -EINVAL;

2183
	cp = kstrdup(task_security(p), GFP_KERNEL);
2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206
	if (cp == NULL)
		return -ENOMEM;

	slen = strlen(cp);
	*value = cp;
	return slen;
}

/**
 * smack_setprocattr - Smack process attribute setting
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: the value to set
 * @size: the size of the value
 *
 * Sets the Smack value of the task. Only setting self
 * is permitted and only with privilege
 *
 * Returns the length of the smack label or an error code
 */
static int smack_setprocattr(struct task_struct *p, char *name,
			     void *value, size_t size)
{
D
David Howells 已提交
2207
	struct cred *new;
2208 2209 2210 2211 2212 2213 2214 2215 2216
	char *newsmack;

	/*
	 * Changing another process' Smack value is too dangerous
	 * and supports no sane use case.
	 */
	if (p != current)
		return -EPERM;

2217 2218 2219
	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;

2220 2221 2222 2223 2224 2225 2226 2227 2228 2229
	if (value == NULL || size == 0 || size >= SMK_LABELLEN)
		return -EINVAL;

	if (strcmp(name, "current") != 0)
		return -EINVAL;

	newsmack = smk_import(value, size);
	if (newsmack == NULL)
		return -EINVAL;

2230 2231 2232 2233 2234 2235
	/*
	 * No process is ever allowed the web ("@") label.
	 */
	if (newsmack == smack_known_web.smk_known)
		return -EPERM;

D
David Howells 已提交
2236
	new = prepare_creds();
2237
	if (new == NULL)
D
David Howells 已提交
2238 2239 2240
		return -ENOMEM;
	new->security = newsmack;
	commit_creds(new);
2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277
	return size;
}

/**
 * smack_unix_stream_connect - Smack access on UDS
 * @sock: one socket
 * @other: the other socket
 * @newsk: unused
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_stream_connect(struct socket *sock,
				     struct socket *other, struct sock *newsk)
{
	struct inode *sp = SOCK_INODE(sock);
	struct inode *op = SOCK_INODE(other);

	return smk_access(smk_of_inode(sp), smk_of_inode(op), MAY_READWRITE);
}

/**
 * smack_unix_may_send - Smack access on UDS
 * @sock: one socket
 * @other: the other socket
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_may_send(struct socket *sock, struct socket *other)
{
	struct inode *sp = SOCK_INODE(sock);
	struct inode *op = SOCK_INODE(other);

	return smk_access(smk_of_inode(sp), smk_of_inode(op), MAY_WRITE);
}

2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320
/**
 * smack_socket_sendmsg - Smack check based on destination host
 * @sock: the socket
 * @msghdr: the message
 * @size: the size of the message
 *
 * Return 0 if the current subject can write to the destination
 * host. This is only a question if the destination is a single
 * label host.
 */
static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
				int size)
{
	struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
	struct socket_smack *ssp = sock->sk->sk_security;
	char *hostsp;
	int rc;

	/*
	 * Perfectly reasonable for this to be NULL
	 */
	if (sip == NULL || sip->sin_family != PF_INET)
		return 0;

	hostsp = smack_host_label(sip);
	if (hostsp == NULL) {
		if (ssp->smk_labeled != SMACK_CIPSO_SOCKET)
			return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
		return 0;
	}

	rc = smk_access(ssp->smk_out, hostsp, MAY_WRITE);
	if (rc != 0)
		return rc;

	if (ssp->smk_labeled != SMACK_UNLABELED_SOCKET)
		return smack_netlabel(sock->sk, SMACK_UNLABELED_SOCKET);

	return 0;

}


2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331
/**
 * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat
 * 	pair to smack
 * @sap: netlabel secattr
 * @sip: where to put the result
 *
 * Copies a smack label into sip
 */
static void smack_from_secattr(struct netlbl_lsm_secattr *sap, char *sip)
{
	char smack[SMK_LABELLEN];
2332
	char *sp;
2333 2334
	int pcat;

2335
	if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
2336
		/*
2337
		 * Looks like a CIPSO packet.
2338 2339 2340
		 * If there are flags but no level netlabel isn't
		 * behaving the way we expect it to.
		 *
2341
		 * Get the categories, if any
2342 2343 2344 2345
		 * Without guidance regarding the smack value
		 * for the packet fall back on the network
		 * ambient value.
		 */
2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367
		memset(smack, '\0', SMK_LABELLEN);
		if ((sap->flags & NETLBL_SECATTR_MLS_CAT) != 0)
			for (pcat = -1;;) {
				pcat = netlbl_secattr_catmap_walk(
					sap->attr.mls.cat, pcat + 1);
				if (pcat < 0)
					break;
				smack_catset_bit(pcat, smack);
			}
		/*
		 * If it is CIPSO using smack direct mapping
		 * we are already done. WeeHee.
		 */
		if (sap->attr.mls.lvl == smack_cipso_direct) {
			memcpy(sip, smack, SMK_MAXLEN);
			return;
		}
		/*
		 * Look it up in the supplied table if it is not
		 * a direct mapping.
		 */
		smack_from_cipso(sap->attr.mls.lvl, smack, sip);
2368 2369
		return;
	}
2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383
	if ((sap->flags & NETLBL_SECATTR_SECID) != 0) {
		/*
		 * Looks like a fallback, which gives us a secid.
		 */
		sp = smack_from_secid(sap->attr.secid);
		/*
		 * This has got to be a bug because it is
		 * impossible to specify a fallback without
		 * specifying the label, which will ensure
		 * it has a secid, and the only way to get a
		 * secid is from a fallback.
		 */
		BUG_ON(sp == NULL);
		strncpy(sip, sp, SMK_MAXLEN);
2384 2385 2386
		return;
	}
	/*
2387 2388 2389
	 * Without guidance regarding the smack value
	 * for the packet fall back on the network
	 * ambient value.
2390
	 */
2391
	strncpy(sip, smack_net_ambient, SMK_MAXLEN);
2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406
	return;
}

/**
 * smack_socket_sock_rcv_skb - Smack packet delivery access check
 * @sk: socket
 * @skb: packet
 *
 * Returns 0 if the packet should be delivered, an error code otherwise
 */
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
	struct netlbl_lsm_secattr secattr;
	struct socket_smack *ssp = sk->sk_security;
	char smack[SMK_LABELLEN];
2407
	char *csp;
2408 2409 2410 2411 2412 2413 2414 2415 2416
	int rc;

	if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
		return 0;

	/*
	 * Translate what netlabel gave us.
	 */
	netlbl_secattr_init(&secattr);
2417

2418
	rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr);
2419
	if (rc == 0) {
2420
		smack_from_secattr(&secattr, smack);
2421 2422 2423 2424
		csp = smack;
	} else
		csp = smack_net_ambient;

2425
	netlbl_secattr_destroy(&secattr);
2426

2427 2428 2429 2430 2431 2432
	/*
	 * Receiving a packet requires that the other end
	 * be able to write here. Read access is not required.
	 * This is the simplist possible security model
	 * for networking.
	 */
2433
	rc = smk_access(csp, ssp->smk_in, MAY_WRITE);
2434 2435 2436
	if (rc != 0)
		netlbl_skbuff_err(skb, rc, 0);
	return rc;
2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540
}

/**
 * smack_socket_getpeersec_stream - pull in packet label
 * @sock: the socket
 * @optval: user's destination
 * @optlen: size thereof
 * @len: max thereoe
 *
 * returns zero on success, an error code otherwise
 */
static int smack_socket_getpeersec_stream(struct socket *sock,
					  char __user *optval,
					  int __user *optlen, unsigned len)
{
	struct socket_smack *ssp;
	int slen;
	int rc = 0;

	ssp = sock->sk->sk_security;
	slen = strlen(ssp->smk_packet) + 1;

	if (slen > len)
		rc = -ERANGE;
	else if (copy_to_user(optval, ssp->smk_packet, slen) != 0)
		rc = -EFAULT;

	if (put_user(slen, optlen) != 0)
		rc = -EFAULT;

	return rc;
}


/**
 * smack_socket_getpeersec_dgram - pull in packet label
 * @sock: the socket
 * @skb: packet data
 * @secid: pointer to where to put the secid of the packet
 *
 * Sets the netlabel socket state on sk from parent
 */
static int smack_socket_getpeersec_dgram(struct socket *sock,
					 struct sk_buff *skb, u32 *secid)

{
	struct netlbl_lsm_secattr secattr;
	struct sock *sk;
	char smack[SMK_LABELLEN];
	int family = PF_INET;
	u32 s;
	int rc;

	/*
	 * Only works for families with packets.
	 */
	if (sock != NULL) {
		sk = sock->sk;
		if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
			return 0;
		family = sk->sk_family;
	}
	/*
	 * Translate what netlabel gave us.
	 */
	netlbl_secattr_init(&secattr);
	rc = netlbl_skbuff_getattr(skb, family, &secattr);
	if (rc == 0)
		smack_from_secattr(&secattr, smack);
	netlbl_secattr_destroy(&secattr);

	/*
	 * Give up if we couldn't get anything
	 */
	if (rc != 0)
		return rc;

	s = smack_to_secid(smack);
	if (s == 0)
		return -EINVAL;

	*secid = s;
	return 0;
}

/**
 * smack_sock_graft - graft access state between two sockets
 * @sk: fresh sock
 * @parent: donor socket
 *
 * Sets the netlabel socket state on sk from parent
 */
static void smack_sock_graft(struct sock *sk, struct socket *parent)
{
	struct socket_smack *ssp;
	int rc;

	if (sk == NULL)
		return;

	if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
		return;

	ssp = sk->sk_security;
2541
	ssp->smk_in = ssp->smk_out = current_security();
2542 2543
	ssp->smk_packet[0] = '\0';

2544
	rc = smack_netlabel(sk, SMACK_CIPSO_SOCKET);
2545 2546 2547
	if (rc != 0)
		printk(KERN_WARNING "Smack: \"%s\" netlbl error %d.\n",
		       __func__, -rc);
2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602
}

/**
 * smack_inet_conn_request - Smack access check on connect
 * @sk: socket involved
 * @skb: packet
 * @req: unused
 *
 * Returns 0 if a task with the packet label could write to
 * the socket, otherwise an error code
 */
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
				   struct request_sock *req)
{
	struct netlbl_lsm_secattr skb_secattr;
	struct socket_smack *ssp = sk->sk_security;
	char smack[SMK_LABELLEN];
	int rc;

	if (skb == NULL)
		return -EACCES;

	netlbl_secattr_init(&skb_secattr);
	rc = netlbl_skbuff_getattr(skb, sk->sk_family, &skb_secattr);
	if (rc == 0)
		smack_from_secattr(&skb_secattr, smack);
	else
		strncpy(smack, smack_known_huh.smk_known, SMK_MAXLEN);
	netlbl_secattr_destroy(&skb_secattr);
	/*
	 * Receiving a packet requires that the other end
	 * be able to write here. Read access is not required.
	 *
	 * If the request is successful save the peer's label
	 * so that SO_PEERCRED can report it.
	 */
	rc = smk_access(smack, ssp->smk_in, MAY_WRITE);
	if (rc == 0)
		strncpy(ssp->smk_packet, smack, SMK_MAXLEN);

	return rc;
}

/*
 * Key management security hooks
 *
 * Casey has not tested key support very heavily.
 * The permission check is most likely too restrictive.
 * If you care about keys please have a look.
 */
#ifdef CONFIG_KEYS

/**
 * smack_key_alloc - Set the key security blob
 * @key: object
D
David Howells 已提交
2603
 * @cred: the credentials to use
2604 2605 2606 2607 2608 2609
 * @flags: unused
 *
 * No allocation required
 *
 * Returns 0
 */
D
David Howells 已提交
2610
static int smack_key_alloc(struct key *key, const struct cred *cred,
2611 2612
			   unsigned long flags)
{
D
David Howells 已提交
2613
	key->security = cred->security;
2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630
	return 0;
}

/**
 * smack_key_free - Clear the key security blob
 * @key: the object
 *
 * Clear the blob pointer
 */
static void smack_key_free(struct key *key)
{
	key->security = NULL;
}

/*
 * smack_key_permission - Smack access on a key
 * @key_ref: gets to the object
D
David Howells 已提交
2631
 * @cred: the credentials to use
2632 2633 2634 2635 2636 2637
 * @perm: unused
 *
 * Return 0 if the task has read and write to the object,
 * an error code otherwise
 */
static int smack_key_permission(key_ref_t key_ref,
D
David Howells 已提交
2638
				const struct cred *cred, key_perm_t perm)
2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653
{
	struct key *keyp;

	keyp = key_ref_to_ptr(key_ref);
	if (keyp == NULL)
		return -EINVAL;
	/*
	 * If the key hasn't been initialized give it access so that
	 * it may do so.
	 */
	if (keyp->security == NULL)
		return 0;
	/*
	 * This should not occur
	 */
D
David Howells 已提交
2654
	if (cred->security == NULL)
2655 2656
		return -EACCES;

D
David Howells 已提交
2657
	return smk_access(cred->security, keyp->security, MAY_READWRITE);
2658 2659 2660
}
#endif /* CONFIG_KEYS */

2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693
/*
 * Smack Audit hooks
 *
 * Audit requires a unique representation of each Smack specific
 * rule. This unique representation is used to distinguish the
 * object to be audited from remaining kernel objects and also
 * works as a glue between the audit hooks.
 *
 * Since repository entries are added but never deleted, we'll use
 * the smack_known label address related to the given audit rule as
 * the needed unique representation. This also better fits the smack
 * model where nearly everything is a label.
 */
#ifdef CONFIG_AUDIT

/**
 * smack_audit_rule_init - Initialize a smack audit rule
 * @field: audit rule fields given from user-space (audit.h)
 * @op: required testing operator (=, !=, >, <, ...)
 * @rulestr: smack label to be audited
 * @vrule: pointer to save our own audit rule representation
 *
 * Prepare to audit cases where (@field @op @rulestr) is true.
 * The label to be audited is created if necessay.
 */
static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
	char **rule = (char **)vrule;
	*rule = NULL;

	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
		return -EINVAL;

2694
	if (op != Audit_equal && op != Audit_not_equal)
2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757
		return -EINVAL;

	*rule = smk_import(rulestr, 0);

	return 0;
}

/**
 * smack_audit_rule_known - Distinguish Smack audit rules
 * @krule: rule of interest, in Audit kernel representation format
 *
 * This is used to filter Smack rules from remaining Audit ones.
 * If it's proved that this rule belongs to us, the
 * audit_rule_match hook will be called to do the final judgement.
 */
static int smack_audit_rule_known(struct audit_krule *krule)
{
	struct audit_field *f;
	int i;

	for (i = 0; i < krule->field_count; i++) {
		f = &krule->fields[i];

		if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
			return 1;
	}

	return 0;
}

/**
 * smack_audit_rule_match - Audit given object ?
 * @secid: security id for identifying the object to test
 * @field: audit rule flags given from user-space
 * @op: required testing operator
 * @vrule: smack internal rule presentation
 * @actx: audit context associated with the check
 *
 * The core Audit hook. It's used to take the decision of
 * whether to audit or not to audit a given object.
 */
static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
				  struct audit_context *actx)
{
	char *smack;
	char *rule = vrule;

	if (!rule) {
		audit_log(actx, GFP_KERNEL, AUDIT_SELINUX_ERR,
			  "Smack: missing rule\n");
		return -ENOENT;
	}

	if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
		return 0;

	smack = smack_from_secid(secid);

	/*
	 * No need to do string comparisons. If a match occurs,
	 * both pointers will point to the same smack_known
	 * label.
	 */
2758
	if (op == Audit_equal)
2759
		return (rule == smack);
2760
	if (op == Audit_not_equal)
2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778
		return (rule != smack);

	return 0;
}

/**
 * smack_audit_rule_free - free smack rule representation
 * @vrule: rule to be freed.
 *
 * No memory was allocated.
 */
static void smack_audit_rule_free(void *vrule)
{
	/* No-op */
}

#endif /* CONFIG_AUDIT */

2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
/*
 * smack_secid_to_secctx - return the smack label for a secid
 * @secid: incoming integer
 * @secdata: destination
 * @seclen: how long it is
 *
 * Exists for networking code.
 */
static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
	char *sp = smack_from_secid(secid);

	*secdata = sp;
	*seclen = strlen(sp);
	return 0;
}

2796 2797 2798 2799 2800 2801 2802 2803
/*
 * smack_secctx_to_secid - return the secid for a smack label
 * @secdata: smack label
 * @seclen: how long result is
 * @secid: outgoing integer
 *
 * Exists for audit and networking code.
 */
2804
static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
2805 2806 2807 2808 2809
{
	*secid = smack_to_secid(secdata);
	return 0;
}

2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821
/*
 * smack_release_secctx - don't do anything.
 * @key_ref: unused
 * @context: unused
 * @perm: unused
 *
 * Exists to make sure nothing gets done, and properly
 */
static void smack_release_secctx(char *secdata, u32 seclen)
{
}

2822 2823 2824
struct security_operations smack_ops = {
	.name =				"smack",

2825 2826
	.ptrace_may_access =		smack_ptrace_may_access,
	.ptrace_traceme =		smack_ptrace_traceme,
2827
	.capget = 			cap_capget,
D
David Howells 已提交
2828
	.capset = 			cap_capset,
2829 2830 2831 2832 2833
	.capable = 			cap_capable,
	.syslog = 			smack_syslog,
	.settime = 			cap_settime,
	.vm_enough_memory = 		cap_vm_enough_memory,

2834
	.bprm_set_creds = 		cap_bprm_set_creds,
2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858
	.bprm_secureexec = 		cap_bprm_secureexec,

	.sb_alloc_security = 		smack_sb_alloc_security,
	.sb_free_security = 		smack_sb_free_security,
	.sb_copy_data = 		smack_sb_copy_data,
	.sb_kern_mount = 		smack_sb_kern_mount,
	.sb_statfs = 			smack_sb_statfs,
	.sb_mount = 			smack_sb_mount,
	.sb_umount = 			smack_sb_umount,

	.inode_alloc_security = 	smack_inode_alloc_security,
	.inode_free_security = 		smack_inode_free_security,
	.inode_init_security = 		smack_inode_init_security,
	.inode_link = 			smack_inode_link,
	.inode_unlink = 		smack_inode_unlink,
	.inode_rmdir = 			smack_inode_rmdir,
	.inode_rename = 		smack_inode_rename,
	.inode_permission = 		smack_inode_permission,
	.inode_setattr = 		smack_inode_setattr,
	.inode_getattr = 		smack_inode_getattr,
	.inode_setxattr = 		smack_inode_setxattr,
	.inode_post_setxattr = 		smack_inode_post_setxattr,
	.inode_getxattr = 		smack_inode_getxattr,
	.inode_removexattr = 		smack_inode_removexattr,
2859 2860
	.inode_need_killpriv =		cap_inode_need_killpriv,
	.inode_killpriv =		cap_inode_killpriv,
2861 2862 2863
	.inode_getsecurity = 		smack_inode_getsecurity,
	.inode_setsecurity = 		smack_inode_setsecurity,
	.inode_listsecurity = 		smack_inode_listsecurity,
2864
	.inode_getsecid =		smack_inode_getsecid,
2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875

	.file_permission = 		smack_file_permission,
	.file_alloc_security = 		smack_file_alloc_security,
	.file_free_security = 		smack_file_free_security,
	.file_ioctl = 			smack_file_ioctl,
	.file_lock = 			smack_file_lock,
	.file_fcntl = 			smack_file_fcntl,
	.file_set_fowner = 		smack_file_set_fowner,
	.file_send_sigiotask = 		smack_file_send_sigiotask,
	.file_receive = 		smack_file_receive,

2876
	.cred_free =			smack_cred_free,
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David Howells 已提交
2877 2878
	.cred_prepare =			smack_cred_prepare,
	.cred_commit =			smack_cred_commit,
2879 2880
	.kernel_act_as =		smack_kernel_act_as,
	.kernel_create_files_as =	smack_kernel_create_files_as,
D
David Howells 已提交
2881
	.task_fix_setuid =		cap_task_fix_setuid,
2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894
	.task_setpgid = 		smack_task_setpgid,
	.task_getpgid = 		smack_task_getpgid,
	.task_getsid = 			smack_task_getsid,
	.task_getsecid = 		smack_task_getsecid,
	.task_setnice = 		smack_task_setnice,
	.task_setioprio = 		smack_task_setioprio,
	.task_getioprio = 		smack_task_getioprio,
	.task_setscheduler = 		smack_task_setscheduler,
	.task_getscheduler = 		smack_task_getscheduler,
	.task_movememory = 		smack_task_movememory,
	.task_kill = 			smack_task_kill,
	.task_wait = 			smack_task_wait,
	.task_to_inode = 		smack_task_to_inode,
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	.task_prctl =			cap_task_prctl,
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	.ipc_permission = 		smack_ipc_permission,
2898
	.ipc_getsecid =			smack_ipc_getsecid,
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	.msg_msg_alloc_security = 	smack_msg_msg_alloc_security,
	.msg_msg_free_security = 	smack_msg_msg_free_security,

	.msg_queue_alloc_security = 	smack_msg_queue_alloc_security,
	.msg_queue_free_security = 	smack_msg_queue_free_security,
	.msg_queue_associate = 		smack_msg_queue_associate,
	.msg_queue_msgctl = 		smack_msg_queue_msgctl,
	.msg_queue_msgsnd = 		smack_msg_queue_msgsnd,
	.msg_queue_msgrcv = 		smack_msg_queue_msgrcv,

	.shm_alloc_security = 		smack_shm_alloc_security,
	.shm_free_security = 		smack_shm_free_security,
	.shm_associate = 		smack_shm_associate,
	.shm_shmctl = 			smack_shm_shmctl,
	.shm_shmat = 			smack_shm_shmat,

	.sem_alloc_security = 		smack_sem_alloc_security,
	.sem_free_security = 		smack_sem_free_security,
	.sem_associate = 		smack_sem_associate,
	.sem_semctl = 			smack_sem_semctl,
	.sem_semop = 			smack_sem_semop,

	.netlink_send =			cap_netlink_send,
	.netlink_recv = 		cap_netlink_recv,

	.d_instantiate = 		smack_d_instantiate,

	.getprocattr = 			smack_getprocattr,
	.setprocattr = 			smack_setprocattr,

	.unix_stream_connect = 		smack_unix_stream_connect,
	.unix_may_send = 		smack_unix_may_send,

	.socket_post_create = 		smack_socket_post_create,
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	.socket_connect =		smack_socket_connect,
	.socket_sendmsg =		smack_socket_sendmsg,
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	.socket_sock_rcv_skb = 		smack_socket_sock_rcv_skb,
	.socket_getpeersec_stream =	smack_socket_getpeersec_stream,
	.socket_getpeersec_dgram =	smack_socket_getpeersec_dgram,
	.sk_alloc_security = 		smack_sk_alloc_security,
	.sk_free_security = 		smack_sk_free_security,
	.sock_graft = 			smack_sock_graft,
	.inet_conn_request = 		smack_inet_conn_request,
2943

2944 2945 2946 2947 2948 2949
 /* key management security hooks */
#ifdef CONFIG_KEYS
	.key_alloc = 			smack_key_alloc,
	.key_free = 			smack_key_free,
	.key_permission = 		smack_key_permission,
#endif /* CONFIG_KEYS */
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 /* Audit hooks */
#ifdef CONFIG_AUDIT
	.audit_rule_init =		smack_audit_rule_init,
	.audit_rule_known =		smack_audit_rule_known,
	.audit_rule_match =		smack_audit_rule_match,
	.audit_rule_free =		smack_audit_rule_free,
#endif /* CONFIG_AUDIT */

2959
	.secid_to_secctx = 		smack_secid_to_secctx,
2960
	.secctx_to_secid = 		smack_secctx_to_secid,
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	.release_secctx = 		smack_release_secctx,
};

/**
 * smack_init - initialize the smack system
 *
 * Returns 0
 */
static __init int smack_init(void)
{
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	struct cred *cred;

2973 2974 2975
	if (!security_module_enable(&smack_ops))
		return 0;

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	printk(KERN_INFO "Smack:  Initializing.\n");

	/*
	 * Set the security state for the initial task.
	 */
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	cred = (struct cred *) current->cred;
	cred->security = &smack_known_floor.smk_known;
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	/*
	 * Initialize locks
	 */
	spin_lock_init(&smack_known_huh.smk_cipsolock);
	spin_lock_init(&smack_known_hat.smk_cipsolock);
	spin_lock_init(&smack_known_star.smk_cipsolock);
	spin_lock_init(&smack_known_floor.smk_cipsolock);
	spin_lock_init(&smack_known_invalid.smk_cipsolock);

	/*
	 * Register with LSM
	 */
	if (register_security(&smack_ops))
		panic("smack: Unable to register with kernel.\n");

	return 0;
}

/*
 * Smack requires early initialization in order to label
 * all processes and objects when they are created.
 */
security_initcall(smack_init);