security/tomoyo/tomoyo.c

   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 #include "tomoyo.h"
  15 #include "realpath.h"
  16
  17 static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
  18 {
  19         new->security = NULL;
  20         return 0;
  21 }
  22
  23 static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
  24                                gfp_t gfp)
  25 {
  26         /*
  27          * Since "struct tomoyo_domain_info *" is a sharable pointer,
  28          * we don't need to duplicate.
  29          */
  30         new->security = old->security;
  31         return 0;
  32 }
  33
  34 static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
  35 {
  36         /*
  37          * Since "struct tomoyo_domain_info *" is a sharable pointer,
  38          * we don't need to duplicate.
  39          */
  40         new->security = old->security;
  41 }
  42
  43 static 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          * Tell tomoyo_bprm_check_security() is called for the first time of an
  65          * execve operation.
  66          */
  67         bprm->cred->security = NULL;
  68         return 0;
  69 }
  70
  71 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
  72 {
  73         struct tomoyo_domain_info *domain = bprm->cred->security;
  74
  75         /*
  76          * Execute permission is checked against pathname passed to do_execve()
  77          * using current domain.
  78          */
  79         if (!domain)
  80                 return tomoyo_find_next_domain(bprm);
  81         /*
  82          * Read permission is checked against interpreters using next domain.
  83          */
  84         return tomoyo_check_open_permission(domain, &bprm->file->f_path, O_RDONLY);
  85 }
  86
  87 static int tomoyo_path_truncate(struct path *path, loff_t length,
  88                                 unsigned int time_attrs)
  89 {
  90         return tomoyo_check_1path_perm(tomoyo_domain(),
  91                                        TOMOYO_TYPE_TRUNCATE_ACL,
  92                                        path);
  93 }
  94
  95 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
  96 {
  97         struct path path = { parent->mnt, dentry };
  98         return tomoyo_check_1path_perm(tomoyo_domain(),
  99                                        TOMOYO_TYPE_UNLINK_ACL,
 100                                        &path);
 101 }
 102
 103 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 104                              int mode)
 105 {
 106         struct path path = { parent->mnt, dentry };
 107         return tomoyo_check_1path_perm(tomoyo_domain(),
 108                                        TOMOYO_TYPE_MKDIR_ACL,
 109                                        &path);
 110 }
 111
 112 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 113 {
 114         struct path path = { parent->mnt, dentry };
 115         return tomoyo_check_1path_perm(tomoyo_domain(),
 116                                        TOMOYO_TYPE_RMDIR_ACL,
 117                                        &path);
 118 }
 119
 120 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 121                                const char *old_name)
 122 {
 123         struct path path = { parent->mnt, dentry };
 124         return tomoyo_check_1path_perm(tomoyo_domain(),
 125                                        TOMOYO_TYPE_SYMLINK_ACL,
 126                                        &path);
 127 }
 128
 129 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 130                              int mode, unsigned int dev)
 131 {
 132         struct path path = { parent->mnt, dentry };
 133         int type = TOMOYO_TYPE_CREATE_ACL;
 134
 135         switch (mode & S_IFMT) {
 136         case S_IFCHR:
 137                 type = TOMOYO_TYPE_MKCHAR_ACL;
 138                 break;
 139         case S_IFBLK:
 140                 type = TOMOYO_TYPE_MKBLOCK_ACL;
 141                 break;
 142         case S_IFIFO:
 143                 type = TOMOYO_TYPE_MKFIFO_ACL;
 144                 break;
 145         case S_IFSOCK:
 146                 type = TOMOYO_TYPE_MKSOCK_ACL;
 147                 break;
 148         }
 149         return tomoyo_check_1path_perm(tomoyo_domain(),
 150                                        type, &path);
 151 }
 152
 153 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 154                             struct dentry *new_dentry)
 155 {
 156         struct path path1 = { new_dir->mnt, old_dentry };
 157         struct path path2 = { new_dir->mnt, new_dentry };
 158         return tomoyo_check_2path_perm(tomoyo_domain(),
 159                                        TOMOYO_TYPE_LINK_ACL,
 160                                        &path1, &path2);
 161 }
 162
 163 static int tomoyo_path_rename(struct path *old_parent,
 164                               struct dentry *old_dentry,
 165                               struct path *new_parent,
 166                               struct dentry *new_dentry)
 167 {
 168         struct path path1 = { old_parent->mnt, old_dentry };
 169         struct path path2 = { new_parent->mnt, new_dentry };
 170         return tomoyo_check_2path_perm(tomoyo_domain(),
 171                                        TOMOYO_TYPE_RENAME_ACL,
 172                                        &path1, &path2);
 173 }
 174
 175 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 176                              unsigned long arg)
 177 {
 178         if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
 179                 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
 180         return 0;
 181 }
 182
 183 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 184 {
 185         int flags = f->f_flags;
 186         /* Don't check read permission here if called from do_execve(). */
 187         if (current->in_execve)
 188                 return 0;
 189         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 190 }
 191
 192 /*
 193  * tomoyo_security_ops is a "struct security_operations" which is used for
 194  * registering TOMOYO.
 195  */
 196 static struct security_operations tomoyo_security_ops = {
 197         .name                = "tomoyo",
 198         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 199         .cred_prepare        = tomoyo_cred_prepare,
 200         .cred_transfer       = tomoyo_cred_transfer,
 201         .bprm_set_creds      = tomoyo_bprm_set_creds,
 202         .bprm_check_security = tomoyo_bprm_check_security,
 203         .file_fcntl          = tomoyo_file_fcntl,
 204         .dentry_open         = tomoyo_dentry_open,
 205         .path_truncate       = tomoyo_path_truncate,
 206         .path_unlink         = tomoyo_path_unlink,
 207         .path_mkdir          = tomoyo_path_mkdir,
 208         .path_rmdir          = tomoyo_path_rmdir,
 209         .path_symlink        = tomoyo_path_symlink,
 210         .path_mknod          = tomoyo_path_mknod,
 211         .path_link           = tomoyo_path_link,
 212         .path_rename         = tomoyo_path_rename,
 213 };
 214
 215 static int __init tomoyo_init(void)
 216 {
 217         struct cred *cred = (struct cred *) current_cred();
 218
 219         if (!security_module_enable(&tomoyo_security_ops))
 220                 return 0;
 221         /* register ourselves with the security framework */
 222         if (register_security(&tomoyo_security_ops))
 223                 panic("Failure registering TOMOYO Linux");
 224         printk(KERN_INFO "TOMOYO Linux initialized\n");
 225         cred->security = &tomoyo_kernel_domain;
 226         tomoyo_realpath_init();
 227         return 0;
 228 }
 229
 230 security_initcall(tomoyo_init);