Pileus Git - ~andy/linux/blob - security/tomoyo/tomoyo.c

   1 /*
   2  * security/tomoyo/tomoyo.c
   3  *
   4  * LSM hooks for TOMOYO Linux.
   5  *
   6  * Copyright (C) 2005-2010  NTT DATA CORPORATION
   7  */
   8
   9 #include <linux/security.h>
  10 #include "common.h"
  11
  12 static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
  13 {
  14         new->security = NULL;
  15         return 0;
  16 }
  17
  18 static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
  19                                gfp_t gfp)
  20 {
  21         struct tomoyo_domain_info *domain = old->security;
  22         new->security = domain;
  23         if (domain)
  24                 atomic_inc(&domain->users);
  25         return 0;
  26 }
  27
  28 static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
  29 {
  30         tomoyo_cred_prepare(new, old, 0);
  31 }
  32
  33 static void tomoyo_cred_free(struct cred *cred)
  34 {
  35         struct tomoyo_domain_info *domain = cred->security;
  36         if (domain)
  37                 atomic_dec(&domain->users);
  38 }
  39
  40 static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
  41 {
  42         int rc;
  43
  44         rc = cap_bprm_set_creds(bprm);
  45         if (rc)
  46                 return rc;
  47
  48         /*
  49          * Do only if this function is called for the first time of an execve
  50          * operation.
  51          */
  52         if (bprm->cred_prepared)
  53                 return 0;
  54         /*
  55          * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
  56          * for the first time.
  57          */
  58         if (!tomoyo_policy_loaded)
  59                 tomoyo_load_policy(bprm->filename);
  60         /*
  61          * Release reference to "struct tomoyo_domain_info" stored inside
  62          * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
  63          * stored inside "bprm->cred->security" will be acquired later inside
  64          * tomoyo_find_next_domain().
  65          */
  66         atomic_dec(&((struct tomoyo_domain_info *)
  67                      bprm->cred->security)->users);
  68         /*
  69          * Tell tomoyo_bprm_check_security() is called for the first time of an
  70          * execve operation.
  71          */
  72         bprm->cred->security = NULL;
  73         return 0;
  74 }
  75
  76 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
  77 {
  78         struct tomoyo_domain_info *domain = bprm->cred->security;
  79
  80         /*
  81          * Execute permission is checked against pathname passed to do_execve()
  82          * using current domain.
  83          */
  84         if (!domain) {
  85                 const int idx = tomoyo_read_lock();
  86                 const int err = tomoyo_find_next_domain(bprm);
  87                 tomoyo_read_unlock(idx);
  88                 return err;
  89         }
  90         /*
  91          * Read permission is checked against interpreters using next domain.
  92          */
  93         return tomoyo_check_open_permission(domain, &bprm->file->f_path, O_RDONLY);
  94 }
  95
  96 static int tomoyo_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
  97 {
  98         struct path path = { mnt, dentry };
  99         return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, &path);
 100 }
 101
 102 static int tomoyo_path_truncate(struct path *path)
 103 {
 104         return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path);
 105 }
 106
 107 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 108 {
 109         struct path path = { parent->mnt, dentry };
 110         return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path);
 111 }
 112
 113 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 114                              int mode)
 115 {
 116         struct path path = { parent->mnt, dentry };
 117         return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
 118                                        mode & S_IALLUGO);
 119 }
 120
 121 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 122 {
 123         struct path path = { parent->mnt, dentry };
 124         return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path);
 125 }
 126
 127 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 128                                const char *old_name)
 129 {
 130         struct path path = { parent->mnt, dentry };
 131         return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path);
 132 }
 133
 134 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 135                              int mode, unsigned int dev)
 136 {
 137         struct path path = { parent->mnt, dentry };
 138         int type = TOMOYO_TYPE_CREATE;
 139         const unsigned int perm = mode & S_IALLUGO;
 140
 141         switch (mode & S_IFMT) {
 142         case S_IFCHR:
 143                 type = TOMOYO_TYPE_MKCHAR;
 144                 break;
 145         case S_IFBLK:
 146                 type = TOMOYO_TYPE_MKBLOCK;
 147                 break;
 148         default:
 149                 goto no_dev;
 150         }
 151         return tomoyo_mkdev_perm(type, &path, perm, dev);
 152  no_dev:
 153         switch (mode & S_IFMT) {
 154         case S_IFIFO:
 155                 type = TOMOYO_TYPE_MKFIFO;
 156                 break;
 157         case S_IFSOCK:
 158                 type = TOMOYO_TYPE_MKSOCK;
 159                 break;
 160         }
 161         return tomoyo_path_number_perm(type, &path, perm);
 162 }
 163
 164 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 165                             struct dentry *new_dentry)
 166 {
 167         struct path path1 = { new_dir->mnt, old_dentry };
 168         struct path path2 = { new_dir->mnt, new_dentry };
 169         return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
 170 }
 171
 172 static int tomoyo_path_rename(struct path *old_parent,
 173                               struct dentry *old_dentry,
 174                               struct path *new_parent,
 175                               struct dentry *new_dentry)
 176 {
 177         struct path path1 = { old_parent->mnt, old_dentry };
 178         struct path path2 = { new_parent->mnt, new_dentry };
 179         return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
 180 }
 181
 182 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 183                              unsigned long arg)
 184 {
 185         if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
 186                 return 0;
 187         return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
 188                                             O_WRONLY | (arg & O_APPEND));
 189 }
 190
 191 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 192 {
 193         int flags = f->f_flags;
 194         /* Don't check read permission here if called from do_execve(). */
 195         if (current->in_execve)
 196                 return 0;
 197         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 198 }
 199
 200 static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
 201                              unsigned long arg)
 202 {
 203         return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
 204 }
 205
 206 static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
 207                              mode_t mode)
 208 {
 209         struct path path = { mnt, dentry };
 210         return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, &path,
 211                                        mode & S_IALLUGO);
 212 }
 213
 214 static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
 215 {
 216         int error = 0;
 217         if (uid != (uid_t) -1)
 218                 error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path, uid);
 219         if (!error && gid != (gid_t) -1)
 220                 error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path, gid);
 221         return error;
 222 }
 223
 224 static int tomoyo_path_chroot(struct path *path)
 225 {
 226         return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path);
 227 }
 228
 229 static int tomoyo_sb_mount(char *dev_name, struct path *path,
 230                            char *type, unsigned long flags, void *data)
 231 {
 232         return tomoyo_mount_permission(dev_name, path, type, flags, data);
 233 }
 234
 235 static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
 236 {
 237         struct path path = { mnt, mnt->mnt_root };
 238         return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path);
 239 }
 240
 241 static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
 242 {
 243         return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
 244 }
 245
 246 /*
 247  * tomoyo_security_ops is a "struct security_operations" which is used for
 248  * registering TOMOYO.
 249  */
 250 static struct security_operations tomoyo_security_ops = {
 251         .name                = "tomoyo",
 252         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 253         .cred_prepare        = tomoyo_cred_prepare,
 254         .cred_transfer       = tomoyo_cred_transfer,
 255         .cred_free           = tomoyo_cred_free,
 256         .bprm_set_creds      = tomoyo_bprm_set_creds,
 257         .bprm_check_security = tomoyo_bprm_check_security,
 258         .file_fcntl          = tomoyo_file_fcntl,
 259         .dentry_open         = tomoyo_dentry_open,
 260         .path_truncate       = tomoyo_path_truncate,
 261         .path_unlink         = tomoyo_path_unlink,
 262         .path_mkdir          = tomoyo_path_mkdir,
 263         .path_rmdir          = tomoyo_path_rmdir,
 264         .path_symlink        = tomoyo_path_symlink,
 265         .path_mknod          = tomoyo_path_mknod,
 266         .path_link           = tomoyo_path_link,
 267         .path_rename         = tomoyo_path_rename,
 268         .inode_getattr       = tomoyo_inode_getattr,
 269         .file_ioctl          = tomoyo_file_ioctl,
 270         .path_chmod          = tomoyo_path_chmod,
 271         .path_chown          = tomoyo_path_chown,
 272         .path_chroot         = tomoyo_path_chroot,
 273         .sb_mount            = tomoyo_sb_mount,
 274         .sb_umount           = tomoyo_sb_umount,
 275         .sb_pivotroot        = tomoyo_sb_pivotroot,
 276 };
 277
 278 /* Lock for GC. */
 279 struct srcu_struct tomoyo_ss;
 280
 281 static int __init tomoyo_init(void)
 282 {
 283         struct cred *cred = (struct cred *) current_cred();
 284
 285         if (!security_module_enable(&tomoyo_security_ops))
 286                 return 0;
 287         /* register ourselves with the security framework */
 288         if (register_security(&tomoyo_security_ops) ||
 289             init_srcu_struct(&tomoyo_ss))
 290                 panic("Failure registering TOMOYO Linux");
 291         printk(KERN_INFO "TOMOYO Linux initialized\n");
 292         cred->security = &tomoyo_kernel_domain;
 293         tomoyo_mm_init();
 294         return 0;
 295 }
 296
 297 security_initcall(tomoyo_init);