linux/security/tomoyo/tomoyo.c
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   1/*
   2 * security/tomoyo/tomoyo.c
   3 *
   4 * LSM hooks for TOMOYO Linux.
   5 *
   6 * Copyright (C) 2005-2009  NTT DATA CORPORATION
   7 *
   8 * Version: 2.2.0   2009/04/01
   9 *
  10 */
  11
  12#include <linux/security.h>
  13#include "common.h"
  14
  15static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
  16{
  17        new->security = NULL;
  18        return 0;
  19}
  20
  21static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
  22                               gfp_t gfp)
  23{
  24        struct tomoyo_domain_info *domain = old->security;
  25        new->security = domain;
  26        if (domain)
  27                atomic_inc(&domain->users);
  28        return 0;
  29}
  30
  31static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
  32{
  33        tomoyo_cred_prepare(new, old, 0);
  34}
  35
  36static void tomoyo_cred_free(struct cred *cred)
  37{
  38        struct tomoyo_domain_info *domain = cred->security;
  39        if (domain)
  40                atomic_dec(&domain->users);
  41}
  42
  43static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
  44{
  45        int rc;
  46
  47        rc = cap_bprm_set_creds(bprm);
  48        if (rc)
  49                return rc;
  50
  51        /*
  52         * Do only if this function is called for the first time of an execve
  53         * operation.
  54         */
  55        if (bprm->cred_prepared)
  56                return 0;
  57        /*
  58         * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
  59         * for the first time.
  60         */
  61        if (!tomoyo_policy_loaded)
  62                tomoyo_load_policy(bprm->filename);
  63        /*
  64         * Release reference to "struct tomoyo_domain_info" stored inside
  65         * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
  66         * stored inside "bprm->cred->security" will be acquired later inside
  67         * tomoyo_find_next_domain().
  68         */
  69        atomic_dec(&((struct tomoyo_domain_info *)
  70                     bprm->cred->security)->users);
  71        /*
  72         * Tell tomoyo_bprm_check_security() is called for the first time of an
  73         * execve operation.
  74         */
  75        bprm->cred->security = NULL;
  76        return 0;
  77}
  78
  79static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
  80{
  81        struct tomoyo_domain_info *domain = bprm->cred->security;
  82
  83        /*
  84         * Execute permission is checked against pathname passed to do_execve()
  85         * using current domain.
  86         */
  87        if (!domain) {
  88                const int idx = tomoyo_read_lock();
  89                const int err = tomoyo_find_next_domain(bprm);
  90                tomoyo_read_unlock(idx);
  91                return err;
  92        }
  93        /*
  94         * Read permission is checked against interpreters using next domain.
  95         */
  96        return tomoyo_check_open_permission(domain, &bprm->file->f_path, O_RDONLY);
  97}
  98
  99static int tomoyo_path_truncate(struct path *path, loff_t length,
 100                                unsigned int time_attrs)
 101{
 102        return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path);
 103}
 104
 105static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 106{
 107        struct path path = { parent->mnt, dentry };
 108        return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path);
 109}
 110
 111static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 112                             int mode)
 113{
 114        struct path path = { parent->mnt, dentry };
 115        return tomoyo_path_perm(TOMOYO_TYPE_MKDIR, &path);
 116}
 117
 118static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 119{
 120        struct path path = { parent->mnt, dentry };
 121        return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path);
 122}
 123
 124static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 125                               const char *old_name)
 126{
 127        struct path path = { parent->mnt, dentry };
 128        return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path);
 129}
 130
 131static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 132                             int mode, unsigned int dev)
 133{
 134        struct path path = { parent->mnt, dentry };
 135        int type = TOMOYO_TYPE_CREATE;
 136
 137        switch (mode & S_IFMT) {
 138        case S_IFCHR:
 139                type = TOMOYO_TYPE_MKCHAR;
 140                break;
 141        case S_IFBLK:
 142                type = TOMOYO_TYPE_MKBLOCK;
 143                break;
 144        case S_IFIFO:
 145                type = TOMOYO_TYPE_MKFIFO;
 146                break;
 147        case S_IFSOCK:
 148                type = TOMOYO_TYPE_MKSOCK;
 149                break;
 150        }
 151        return tomoyo_path_perm(type, &path);
 152}
 153
 154static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 155                            struct dentry *new_dentry)
 156{
 157        struct path path1 = { new_dir->mnt, old_dentry };
 158        struct path path2 = { new_dir->mnt, new_dentry };
 159        return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
 160}
 161
 162static int tomoyo_path_rename(struct path *old_parent,
 163                              struct dentry *old_dentry,
 164                              struct path *new_parent,
 165                              struct dentry *new_dentry)
 166{
 167        struct path path1 = { old_parent->mnt, old_dentry };
 168        struct path path2 = { new_parent->mnt, new_dentry };
 169        return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
 170}
 171
 172static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 173                             unsigned long arg)
 174{
 175        if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
 176                return tomoyo_check_rewrite_permission(file);
 177        return 0;
 178}
 179
 180static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 181{
 182        int flags = f->f_flags;
 183        /* Don't check read permission here if called from do_execve(). */
 184        if (current->in_execve)
 185                return 0;
 186        return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 187}
 188
 189static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
 190                             unsigned long arg)
 191{
 192        return tomoyo_path_perm(TOMOYO_TYPE_IOCTL, &file->f_path);
 193}
 194
 195static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
 196                             mode_t mode)
 197{
 198        struct path path = { mnt, dentry };
 199        return tomoyo_path_perm(TOMOYO_TYPE_CHMOD, &path);
 200}
 201
 202static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
 203{
 204        int error = 0;
 205        if (uid != (uid_t) -1)
 206                error = tomoyo_path_perm(TOMOYO_TYPE_CHOWN, path);
 207        if (!error && gid != (gid_t) -1)
 208                error = tomoyo_path_perm(TOMOYO_TYPE_CHGRP, path);
 209        return error;
 210}
 211
 212static int tomoyo_path_chroot(struct path *path)
 213{
 214        return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path);
 215}
 216
 217static int tomoyo_sb_mount(char *dev_name, struct path *path,
 218                           char *type, unsigned long flags, void *data)
 219{
 220        return tomoyo_path_perm(TOMOYO_TYPE_MOUNT, path);
 221}
 222
 223static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
 224{
 225        struct path path = { mnt, mnt->mnt_root };
 226        return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path);
 227}
 228
 229static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
 230{
 231        return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
 232}
 233
 234/*
 235 * tomoyo_security_ops is a "struct security_operations" which is used for
 236 * registering TOMOYO.
 237 */
 238static struct security_operations tomoyo_security_ops = {
 239        .name                = "tomoyo",
 240        .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 241        .cred_prepare        = tomoyo_cred_prepare,
 242        .cred_transfer       = tomoyo_cred_transfer,
 243        .cred_free           = tomoyo_cred_free,
 244        .bprm_set_creds      = tomoyo_bprm_set_creds,
 245        .bprm_check_security = tomoyo_bprm_check_security,
 246        .file_fcntl          = tomoyo_file_fcntl,
 247        .dentry_open         = tomoyo_dentry_open,
 248        .path_truncate       = tomoyo_path_truncate,
 249        .path_unlink         = tomoyo_path_unlink,
 250        .path_mkdir          = tomoyo_path_mkdir,
 251        .path_rmdir          = tomoyo_path_rmdir,
 252        .path_symlink        = tomoyo_path_symlink,
 253        .path_mknod          = tomoyo_path_mknod,
 254        .path_link           = tomoyo_path_link,
 255        .path_rename         = tomoyo_path_rename,
 256        .file_ioctl          = tomoyo_file_ioctl,
 257        .path_chmod          = tomoyo_path_chmod,
 258        .path_chown          = tomoyo_path_chown,
 259        .path_chroot         = tomoyo_path_chroot,
 260        .sb_mount            = tomoyo_sb_mount,
 261        .sb_umount           = tomoyo_sb_umount,
 262        .sb_pivotroot        = tomoyo_sb_pivotroot,
 263};
 264
 265/* Lock for GC. */
 266struct srcu_struct tomoyo_ss;
 267
 268static int __init tomoyo_init(void)
 269{
 270        struct cred *cred = (struct cred *) current_cred();
 271
 272        if (!security_module_enable(&tomoyo_security_ops))
 273                return 0;
 274        /* register ourselves with the security framework */
 275        if (register_security(&tomoyo_security_ops) ||
 276            init_srcu_struct(&tomoyo_ss))
 277                panic("Failure registering TOMOYO Linux");
 278        printk(KERN_INFO "TOMOYO Linux initialized\n");
 279        cred->security = &tomoyo_kernel_domain;
 280        tomoyo_realpath_init();
 281        return 0;
 282}
 283
 284security_initcall(tomoyo_init);
 285