securityfs_if.c

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/*
 * security/tomoyo/securityfs_if.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 */

#include <linux/security.h>
#include "common.h"

static bool tomoyo_check_task_acl(struct tomoyo_request_info *r,
                  const struct tomoyo_acl_info *ptr)
{
    const struct tomoyo_task_acl *acl = container_of(ptr, typeof(*acl),
                             head);
    return !tomoyo_pathcmp(r->param.task.domainname, acl->domainname);
}

static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
                  size_t count, loff_t *ppos)
{
    char *data;
    int error;
    if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10)
        return -ENOMEM;
    data = kzalloc(count + 1, GFP_NOFS);
    if (!data)
        return -ENOMEM;
    if (copy_from_user(data, buf, count)) {
        error = -EFAULT;
        goto out;
    }
    tomoyo_normalize_line(data);
    if (tomoyo_correct_domain(data)) {
        const int idx = tomoyo_read_lock();
        struct tomoyo_path_info name;
        struct tomoyo_request_info r;
        name.name = data;
        tomoyo_fill_path_info(&name);
        /* Check "task manual_domain_transition" permission. */
        tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
        r.param_type = TOMOYO_TYPE_MANUAL_TASK_ACL;
        r.param.task.domainname = &name;
        tomoyo_check_acl(&r, tomoyo_check_task_acl);
        if (!r.granted)
            error = -EPERM;
        else {
            struct tomoyo_domain_info *new_domain =
                tomoyo_assign_domain(data, true);
            if (!new_domain) {
                error = -ENOENT;
            } else {
                struct cred *cred = prepare_creds();
                if (!cred) {
                    error = -ENOMEM;
                } else {
                    struct tomoyo_domain_info *old_domain =
                        cred->security;
                    cred->security = new_domain;
                    atomic_inc(&new_domain->users);
                    atomic_dec(&old_domain->users);
                    commit_creds(cred);
                    error = 0;
                }
            }
        }
        tomoyo_read_unlock(idx);
    } else
        error = -EINVAL;
out:
    kfree(data);
    return error ? error : count;
}

static ssize_t tomoyo_read_self(struct file *file, char __user *buf,
                size_t count, loff_t *ppos)
{
    const char *domain = tomoyo_domain()->domainname->name;
    loff_t len = strlen(domain);
    loff_t pos = *ppos;
    if (pos >= len || !count)
        return 0;
    len -= pos;
    if (count < len)
        len = count;
    if (copy_to_user(buf, domain + pos, len))
        return -EFAULT;
    *ppos += len;
    return len;
}

/* Operations for /sys/kernel/security/tomoyo/self_domain interface. */
static const struct file_operations tomoyo_self_operations = {
    .write = tomoyo_write_self,
    .read  = tomoyo_read_self,
};

static int tomoyo_open(struct inode *inode, struct file *file)
{
    const int key = ((u8 *) file->f_path.dentry->d_inode->i_private)
        - ((u8 *) NULL);
    return tomoyo_open_control(key, file);
}

static int tomoyo_release(struct inode *inode, struct file *file)
{
    return tomoyo_close_control(file->private_data);
}

static unsigned int tomoyo_poll(struct file *file, poll_table *wait)
{
    return tomoyo_poll_control(file, wait);
}

static ssize_t tomoyo_read(struct file *file, char __user *buf, size_t count,
               loff_t *ppos)
{
    return tomoyo_read_control(file->private_data, buf, count);
}

static ssize_t tomoyo_write(struct file *file, const char __user *buf,
                size_t count, loff_t *ppos)
{
    return tomoyo_write_control(file->private_data, buf, count);
}

/*
 * tomoyo_operations is a "struct file_operations" which is used for handling
 * /sys/kernel/security/tomoyo/ interface.
 *
 * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
 * See tomoyo_io_buffer for internals.
 */
static const struct file_operations tomoyo_operations = {
    .open    = tomoyo_open,
    .release = tomoyo_release,
    .poll    = tomoyo_poll,
    .read    = tomoyo_read,
    .write   = tomoyo_write,
    .llseek  = noop_llseek,
};

static void __init tomoyo_create_entry(const char *name, const umode_t mode,
                       struct dentry *parent, const u8 key)
{
    securityfs_create_file(name, mode, parent, ((u8 *) NULL) + key,
                   &tomoyo_operations);
}

static int __init tomoyo_initerface_init(void)
{
    struct dentry *tomoyo_dir;

    /* Don't create securityfs entries unless registered. */
    if (current_cred()->security != &tomoyo_kernel_domain)
        return 0;

    tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
    tomoyo_create_entry("query",            0600, tomoyo_dir,
                TOMOYO_QUERY);
    tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
                TOMOYO_DOMAINPOLICY);
    tomoyo_create_entry("exception_policy", 0600, tomoyo_dir,
                TOMOYO_EXCEPTIONPOLICY);
    tomoyo_create_entry("audit",            0400, tomoyo_dir,
                TOMOYO_AUDIT);
    tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
                TOMOYO_PROCESS_STATUS);
    tomoyo_create_entry("stat",             0644, tomoyo_dir,
                TOMOYO_STAT);
    tomoyo_create_entry("profile",          0600, tomoyo_dir,
                TOMOYO_PROFILE);
    tomoyo_create_entry("manager",          0600, tomoyo_dir,
                TOMOYO_MANAGER);
    tomoyo_create_entry("version",          0400, tomoyo_dir,
                TOMOYO_VERSION);
    securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL,
                   &tomoyo_self_operations);
    tomoyo_load_builtin_policy();
    return 0;
}

fs_initcall(tomoyo_initerface_init);