tomoyo.c

Go to the documentation of this file.

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

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

static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
{
    new->security = NULL;
    return 0;
}

static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
                   gfp_t gfp)
{
    struct tomoyo_domain_info *domain = old->security;
    new->security = domain;
    if (domain)
        atomic_inc(&domain->users);
    return 0;
}

static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
{
    tomoyo_cred_prepare(new, old, 0);
}

static void tomoyo_cred_free(struct cred *cred)
{
    struct tomoyo_domain_info *domain = cred->security;
    if (domain)
        atomic_dec(&domain->users);
}

static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
{
    int rc;

    rc = cap_bprm_set_creds(bprm);
    if (rc)
        return rc;

    /*
     * Do only if this function is called for the first time of an execve
     * operation.
     */
    if (bprm->cred_prepared)
        return 0;
#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
    /*
     * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
     * for the first time.
     */
    if (!tomoyo_policy_loaded)
        tomoyo_load_policy(bprm->filename);
#endif
    /*
     * Release reference to "struct tomoyo_domain_info" stored inside
     * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
     * stored inside "bprm->cred->security" will be acquired later inside
     * tomoyo_find_next_domain().
     */
    atomic_dec(&((struct tomoyo_domain_info *)
             bprm->cred->security)->users);
    /*
     * Tell tomoyo_bprm_check_security() is called for the first time of an
     * execve operation.
     */
    bprm->cred->security = NULL;
    return 0;
}

static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
{
    struct tomoyo_domain_info *domain = bprm->cred->security;

    /*
     * Execute permission is checked against pathname passed to do_execve()
     * using current domain.
     */
    if (!domain) {
        const int idx = tomoyo_read_lock();
        const int err = tomoyo_find_next_domain(bprm);
        tomoyo_read_unlock(idx);
        return err;
    }
    /*
     * Read permission is checked against interpreters using next domain.
     */
    return tomoyo_check_open_permission(domain, &bprm->file->f_path,
                        O_RDONLY);
}

static int tomoyo_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
    struct path path = { mnt, dentry };
    return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, &path, NULL);
}

static int tomoyo_path_truncate(struct path *path)
{
    return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path, NULL);
}

static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
{
    struct path path = { parent->mnt, dentry };
    return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path, NULL);
}

static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
                 umode_t mode)
{
    struct path path = { parent->mnt, dentry };
    return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
                       mode & S_IALLUGO);
}

static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
{
    struct path path = { parent->mnt, dentry };
    return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path, NULL);
}

static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
                   const char *old_name)
{
    struct path path = { parent->mnt, dentry };
    return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path, old_name);
}

static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
                 umode_t mode, unsigned int dev)
{
    struct path path = { parent->mnt, dentry };
    int type = TOMOYO_TYPE_CREATE;
    const unsigned int perm = mode & S_IALLUGO;

    switch (mode & S_IFMT) {
    case S_IFCHR:
        type = TOMOYO_TYPE_MKCHAR;
        break;
    case S_IFBLK:
        type = TOMOYO_TYPE_MKBLOCK;
        break;
    default:
        goto no_dev;
    }
    return tomoyo_mkdev_perm(type, &path, perm, dev);
 no_dev:
    switch (mode & S_IFMT) {
    case S_IFIFO:
        type = TOMOYO_TYPE_MKFIFO;
        break;
    case S_IFSOCK:
        type = TOMOYO_TYPE_MKSOCK;
        break;
    }
    return tomoyo_path_number_perm(type, &path, perm);
}

static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
                struct dentry *new_dentry)
{
    struct path path1 = { new_dir->mnt, old_dentry };
    struct path path2 = { new_dir->mnt, new_dentry };
    return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
}

static int tomoyo_path_rename(struct path *old_parent,
                  struct dentry *old_dentry,
                  struct path *new_parent,
                  struct dentry *new_dentry)
{
    struct path path1 = { old_parent->mnt, old_dentry };
    struct path path2 = { new_parent->mnt, new_dentry };
    return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
}

static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
                 unsigned long arg)
{
    if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
        return 0;
    return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
                        O_WRONLY | (arg & O_APPEND));
}

static int tomoyo_file_open(struct file *f, const struct cred *cred)
{
    int flags = f->f_flags;
    /* Don't check read permission here if called from do_execve(). */
    if (current->in_execve)
        return 0;
    return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
}

static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
                 unsigned long arg)
{
    return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
}

static int tomoyo_path_chmod(struct path *path, umode_t mode)
{
    return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, path,
                       mode & S_IALLUGO);
}

static int tomoyo_path_chown(struct path *path, kuid_t uid, kgid_t gid)
{
    int error = 0;
    if (uid_valid(uid))
        error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path,
                        from_kuid(&init_user_ns, uid));
    if (!error && gid_valid(gid))
        error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path,
                        from_kgid(&init_user_ns, gid));
    return error;
}

static int tomoyo_path_chroot(struct path *path)
{
    return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL);
}

static int tomoyo_sb_mount(const char *dev_name, struct path *path,
               const char *type, unsigned long flags, void *data)
{
    return tomoyo_mount_permission(dev_name, path, type, flags, data);
}

static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
{
    struct path path = { mnt, mnt->mnt_root };
    return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path, NULL);
}

static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
{
    return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
}

static int tomoyo_socket_listen(struct socket *sock, int backlog)
{
    return tomoyo_socket_listen_permission(sock);
}

static int tomoyo_socket_connect(struct socket *sock, struct sockaddr *addr,
                 int addr_len)
{
    return tomoyo_socket_connect_permission(sock, addr, addr_len);
}

static int tomoyo_socket_bind(struct socket *sock, struct sockaddr *addr,
                  int addr_len)
{
    return tomoyo_socket_bind_permission(sock, addr, addr_len);
}

static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
                 int size)
{
    return tomoyo_socket_sendmsg_permission(sock, msg, size);
}

/*
 * tomoyo_security_ops is a "struct security_operations" which is used for
 * registering TOMOYO.
 */
static struct security_operations tomoyo_security_ops = {
    .name                = "tomoyo",
    .cred_alloc_blank    = tomoyo_cred_alloc_blank,
    .cred_prepare        = tomoyo_cred_prepare,
    .cred_transfer       = tomoyo_cred_transfer,
    .cred_free           = tomoyo_cred_free,
    .bprm_set_creds      = tomoyo_bprm_set_creds,
    .bprm_check_security = tomoyo_bprm_check_security,
    .file_fcntl          = tomoyo_file_fcntl,
    .file_open           = tomoyo_file_open,
    .path_truncate       = tomoyo_path_truncate,
    .path_unlink         = tomoyo_path_unlink,
    .path_mkdir          = tomoyo_path_mkdir,
    .path_rmdir          = tomoyo_path_rmdir,
    .path_symlink        = tomoyo_path_symlink,
    .path_mknod          = tomoyo_path_mknod,
    .path_link           = tomoyo_path_link,
    .path_rename         = tomoyo_path_rename,
    .inode_getattr       = tomoyo_inode_getattr,
    .file_ioctl          = tomoyo_file_ioctl,
    .path_chmod          = tomoyo_path_chmod,
    .path_chown          = tomoyo_path_chown,
    .path_chroot         = tomoyo_path_chroot,
    .sb_mount            = tomoyo_sb_mount,
    .sb_umount           = tomoyo_sb_umount,
    .sb_pivotroot        = tomoyo_sb_pivotroot,
    .socket_bind         = tomoyo_socket_bind,
    .socket_connect      = tomoyo_socket_connect,
    .socket_listen       = tomoyo_socket_listen,
    .socket_sendmsg      = tomoyo_socket_sendmsg,
};

/* Lock for GC. */
struct srcu_struct tomoyo_ss;

static int __init tomoyo_init(void)
{
    struct cred *cred = (struct cred *) current_cred();

    if (!security_module_enable(&tomoyo_security_ops))
        return 0;
    /* register ourselves with the security framework */
    if (register_security(&tomoyo_security_ops) ||
        init_srcu_struct(&tomoyo_ss))
        panic("Failure registering TOMOYO Linux");
    printk(KERN_INFO "TOMOYO Linux initialized\n");
    cred->security = &tomoyo_kernel_domain;
    tomoyo_mm_init();
    return 0;
}

security_initcall(tomoyo_init);