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          * '1' is the result of open_to_namei_flags(O_RDONLY).
  84          */
  85         return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
  86 }
  87
  88 static int tomoyo_path_truncate(struct path *path, loff_t length,
  89                                 unsigned int time_attrs)
  90 {
  91         return tomoyo_check_1path_perm(tomoyo_domain(),
  92                                        TOMOYO_TYPE_TRUNCATE_ACL,
  93                                        path);
  94 }
  95
  96 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
  97 {
  98         struct path path = { parent->mnt, dentry };
  99         return tomoyo_check_1path_perm(tomoyo_domain(),
 100                                        TOMOYO_TYPE_UNLINK_ACL,
 101                                        &path);
 102 }
 103
 104 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 105                              int mode)
 106 {
 107         struct path path = { parent->mnt, dentry };
 108         return tomoyo_check_1path_perm(tomoyo_domain(),
 109                                        TOMOYO_TYPE_MKDIR_ACL,
 110                                        &path);
 111 }
 112
 113 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 114 {
 115         struct path path = { parent->mnt, dentry };
 116         return tomoyo_check_1path_perm(tomoyo_domain(),
 117                                        TOMOYO_TYPE_RMDIR_ACL,
 118                                        &path);
 119 }
 120
 121 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 122                                const char *old_name)
 123 {
 124         struct path path = { parent->mnt, dentry };
 125         return tomoyo_check_1path_perm(tomoyo_domain(),
 126                                        TOMOYO_TYPE_SYMLINK_ACL,
 127                                        &path);
 128 }
 129
 130 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 131                              int mode, unsigned int dev)
 132 {
 133         struct path path = { parent->mnt, dentry };
 134         int type = TOMOYO_TYPE_CREATE_ACL;
 135
 136         switch (mode & S_IFMT) {
 137         case S_IFCHR:
 138                 type = TOMOYO_TYPE_MKCHAR_ACL;
 139                 break;
 140         case S_IFBLK:
 141                 type = TOMOYO_TYPE_MKBLOCK_ACL;
 142                 break;
 143         case S_IFIFO:
 144                 type = TOMOYO_TYPE_MKFIFO_ACL;
 145                 break;
 146         case S_IFSOCK:
 147                 type = TOMOYO_TYPE_MKSOCK_ACL;
 148                 break;
 149         }
 150         return tomoyo_check_1path_perm(tomoyo_domain(),
 151                                        type, &path);
 152 }
 153
 154 static 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_check_2path_perm(tomoyo_domain(),
 160                                        TOMOYO_TYPE_LINK_ACL,
 161                                        &path1, &path2);
 162 }
 163
 164 static int tomoyo_path_rename(struct path *old_parent,
 165                               struct dentry *old_dentry,
 166                               struct path *new_parent,
 167                               struct dentry *new_dentry)
 168 {
 169         struct path path1 = { old_parent->mnt, old_dentry };
 170         struct path path2 = { new_parent->mnt, new_dentry };
 171         return tomoyo_check_2path_perm(tomoyo_domain(),
 172                                        TOMOYO_TYPE_RENAME_ACL,
 173                                        &path1, &path2);
 174 }
 175
 176 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 177                              unsigned long arg)
 178 {
 179         if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
 180                 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
 181         return 0;
 182 }
 183
 184 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 185 {
 186         int flags = f->f_flags;
 187
 188         if ((flags + 1) & O_ACCMODE)
 189                 flags++;
 190         flags |= f->f_flags & (O_APPEND | O_TRUNC);
 191         /* Don't check read permission here if called from do_execve(). */
 192         if (current->in_execve)
 193                 return 0;
 194         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 195 }
 196
 197 /*
 198  * tomoyo_security_ops is a "struct security_operations" which is used for
 199  * registering TOMOYO.
 200  */
 201 static struct security_operations tomoyo_security_ops = {
 202         .name                = "tomoyo",
 203         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 204         .cred_prepare        = tomoyo_cred_prepare,
 205         .cred_transfer       = tomoyo_cred_transfer,
 206         .bprm_set_creds      = tomoyo_bprm_set_creds,
 207         .bprm_check_security = tomoyo_bprm_check_security,
 208         .file_fcntl          = tomoyo_file_fcntl,
 209         .dentry_open         = tomoyo_dentry_open,
 210         .path_truncate       = tomoyo_path_truncate,
 211         .path_unlink         = tomoyo_path_unlink,
 212         .path_mkdir          = tomoyo_path_mkdir,
 213         .path_rmdir          = tomoyo_path_rmdir,
 214         .path_symlink        = tomoyo_path_symlink,
 215         .path_mknod          = tomoyo_path_mknod,
 216         .path_link           = tomoyo_path_link,
 217         .path_rename         = tomoyo_path_rename,
 218 };
 219
 220 static int __init tomoyo_init(void)
 221 {
 222         struct cred *cred = (struct cred *) current_cred();
 223
 224         if (!security_module_enable(&tomoyo_security_ops))
 225                 return 0;
 226         /* register ourselves with the security framework */
 227         if (register_security(&tomoyo_security_ops))
 228                 panic("Failure registering TOMOYO Linux");
 229         printk(KERN_INFO "TOMOYO Linux initialized\n");
 230         cred->security = &tomoyo_kernel_domain;
 231         tomoyo_realpath_init();
 232         return 0;
 233 }
 234
 235 security_initcall(tomoyo_init);