ccs-patch/fs/sakura_chroot.c

/*
 * fs/sakura_chroot.c
 *
 * Implementation of the Domain-Free Mandatory Access Control.
 *
 * Copyright (C) 2005-2008  NTT DATA CORPORATION
 *
 * Version: 1.5.5   2008/09/03
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */
/***** SAKURA Linux start. *****/

#include <linux/ccs_common.h>
#include <linux/sakura.h>
#include <linux/realpath.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 0)
#include <linux/namei.h>
#else
#include <linux/fs.h>
#endif

extern const char *ccs_log_level;

/***** The structure for chroot restrictions. *****/

struct chroot_entry {
        struct chroot_entry *next;
        const struct path_info *dir;
        int is_deleted;
};

/*************************  CHROOT RESTRICTION HANDLER  *************************/

static struct chroot_entry *chroot_list = NULL;

static int AddChrootACL(const char *dir, const int is_delete)
{
        struct chroot_entry *new_entry, *ptr;
        const struct path_info *saved_dir;
        static DECLARE_MUTEX(lock);
        int error = -ENOMEM;
        if (!IsCorrectPath(dir, 1, 0, 1, __FUNCTION__)) return -EINVAL;
        if ((saved_dir = SaveName(dir)) == NULL) return -ENOMEM;
        down(&lock);
        for (ptr = chroot_list; ptr; ptr = ptr->next) {
                if (ptr->dir == saved_dir) {
                        ptr->is_deleted = is_delete;
                        error = 0;
                        goto out;
                }
        }
        if (is_delete) {
                error = -ENOENT;
                goto out;
        }
        if ((new_entry = alloc_element(sizeof(*new_entry))) == NULL) goto out;
        new_entry->dir = saved_dir;
        mb(); /* Avoid out-of-order execution. */
        if ((ptr = chroot_list) != NULL) {
                while (ptr->next) ptr = ptr->next; ptr->next = new_entry;
        } else {
                chroot_list = new_entry;
        }
        error = 0;
        printk("%sAllow chroot() to %s\n", ccs_log_level, dir);
 out:
        up(&lock);
        return error;
}

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
#define PATH_or_NAMEIDATA path
#else
#define PATH_or_NAMEIDATA nameidata
#endif
int CheckChRootPermission(struct PATH_or_NAMEIDATA *path)
{
        int error = -EPERM;
        char *root_name;
        if (!CheckCCSFlags(CCS_SAKURA_RESTRICT_CHROOT)) return 0;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 25) && LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 26)
        root_name = realpath_from_dentry(path->path.dentry, path->path.mnt);
#else
        root_name = realpath_from_dentry(path->dentry, path->mnt);
#endif
        if (root_name) {
                struct path_info dir;
                dir.name = root_name;
                fill_path_info(&dir);
                if (dir.is_dir) {
                        struct chroot_entry *ptr;
                        for (ptr = chroot_list; ptr; ptr = ptr->next) {
                                if (ptr->is_deleted) continue;
                                if (PathMatchesToPattern(&dir, ptr->dir)) {
                                        error = 0;
                                        break;
                                }
                        }
                }
        }
        if (error) {
                const int is_enforce = CheckCCSEnforce(CCS_SAKURA_RESTRICT_CHROOT);
                const char *exename = GetEXE();
                printk("SAKURA-%s: chroot %s (pid=%d:exe=%s): Permission denied.\n", GetMSG(is_enforce), root_name, current->pid, exename);
                if (is_enforce && CheckSupervisor("# %s is requesting\nchroot %s\n", exename, root_name) == 0) error = 0;
                if (exename) ccs_free(exename);
                if (!is_enforce && CheckCCSAccept(CCS_SAKURA_RESTRICT_CHROOT, NULL) && root_name) {
                        AddChrootACL(root_name, 0);
                        UpdateCounter(CCS_UPDATES_COUNTER_SYSTEM_POLICY);
                }
                if (!is_enforce) error = 0;
        }
        ccs_free(root_name);
        return error;
}

int AddChrootPolicy(char *data, const int is_delete)
{
        return AddChrootACL(data, is_delete);
}

int ReadChrootPolicy(struct io_buffer *head)
{
        struct chroot_entry *ptr = head->read_var2;
        if (!ptr) ptr = chroot_list;
        while (ptr) {
                head->read_var2 = ptr;
                if (ptr->is_deleted == 0 && io_printf(head, KEYWORD_ALLOW_CHROOT "%s\n", ptr->dir->name)) break;
                ptr = ptr->next;
        }
        return ptr ? -ENOMEM : 0;
}

/***** SAKURA Linux end. *****/