security/tomoyo/securityfs_if.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * security/tomoyo/securityfs_if.c
   4  *
   5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   6  */
   7
   8 #include <linux/security.h>
   9 #include "common.h"
  10
  11 /**
  12  * tomoyo_check_task_acl - Check permission for task operation.
  13  *
  14  * @r:   Pointer to "struct tomoyo_request_info".
  15  * @ptr: Pointer to "struct tomoyo_acl_info".
  16  *
  17  * Returns true if granted, false otherwise.
  18  */
  19 static bool tomoyo_check_task_acl(struct tomoyo_request_info *r,
  20                                   const struct tomoyo_acl_info *ptr)
  21 {
  22         const struct tomoyo_task_acl *acl = container_of(ptr, typeof(*acl),
  23                                                          head);
  24         return !tomoyo_pathcmp(r->param.task.domainname, acl->domainname);
  25 }
  26
  27 /**
  28  * tomoyo_write_self - write() for /sys/kernel/security/tomoyo/self_domain interface.
  29  *
  30  * @file:  Pointer to "struct file".
  31  * @buf:   Domainname to transit to.
  32  * @count: Size of @buf.
  33  * @ppos:  Unused.
  34  *
  35  * Returns @count on success, negative value otherwise.
  36  *
  37  * If domain transition was permitted but the domain transition failed, this
  38  * function returns error rather than terminating current thread with SIGKILL.
  39  */
  40 static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
  41                               size_t count, loff_t *ppos)
  42 {
  43         char *data;
  44         int error;
  45         if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10)
  46                 return -ENOMEM;
  47         data = memdup_user_nul(buf, count);
  48         if (IS_ERR(data))
  49                 return PTR_ERR(data);
  50         tomoyo_normalize_line(data);
  51         if (tomoyo_correct_domain(data)) {
  52                 const int idx = tomoyo_read_lock();
  53                 struct tomoyo_path_info name;
  54                 struct tomoyo_request_info r;
  55                 name.name = data;
  56                 tomoyo_fill_path_info(&name);
  57                 /* Check "task manual_domain_transition" permission. */
  58                 tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
  59                 r.param_type = TOMOYO_TYPE_MANUAL_TASK_ACL;
  60                 r.param.task.domainname = &name;
  61                 tomoyo_check_acl(&r, tomoyo_check_task_acl);
  62                 if (!r.granted)
  63                         error = -EPERM;
  64                 else {
  65                         struct tomoyo_domain_info *new_domain =
  66                                 tomoyo_assign_domain(data, true);
  67                         if (!new_domain) {
  68                                 error = -ENOENT;
  69                         } else {
  70                                 struct cred *cred = prepare_creds();
  71                                 if (!cred) {
  72                                         error = -ENOMEM;
  73                                 } else {
  74                                         struct tomoyo_domain_info *old_domain =
  75                                                 cred->security;
  76                                         cred->security = new_domain;
  77                                         atomic_inc(&new_domain->users);
  78                                         atomic_dec(&old_domain->users);
  79                                         commit_creds(cred);
  80                                         error = 0;
  81                                 }
  82                         }
  83                 }
  84                 tomoyo_read_unlock(idx);
  85         } else
  86                 error = -EINVAL;
  87         kfree(data);
  88         return error ? error : count;
  89 }
  90
  91 /**
  92  * tomoyo_read_self - read() for /sys/kernel/security/tomoyo/self_domain interface.
  93  *
  94  * @file:  Pointer to "struct file".
  95  * @buf:   Domainname which current thread belongs to.
  96  * @count: Size of @buf.
  97  * @ppos:  Bytes read by now.
  98  *
  99  * Returns read size on success, negative value otherwise.
 100  */
 101 static ssize_t tomoyo_read_self(struct file *file, char __user *buf,
 102                                 size_t count, loff_t *ppos)
 103 {
 104         const char *domain = tomoyo_domain()->domainname->name;
 105         loff_t len = strlen(domain);
 106         loff_t pos = *ppos;
 107         if (pos >= len || !count)
 108                 return 0;
 109         len -= pos;
 110         if (count < len)
 111                 len = count;
 112         if (copy_to_user(buf, domain + pos, len))
 113                 return -EFAULT;
 114         *ppos += len;
 115         return len;
 116 }
 117
 118 /* Operations for /sys/kernel/security/tomoyo/self_domain interface. */
 119 static const struct file_operations tomoyo_self_operations = {
 120         .write = tomoyo_write_self,
 121         .read  = tomoyo_read_self,
 122 };
 123
 124 /**
 125  * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
 126  *
 127  * @inode: Pointer to "struct inode".
 128  * @file:  Pointer to "struct file".
 129  *
 130  * Returns 0 on success, negative value otherwise.
 131  */
 132 static int tomoyo_open(struct inode *inode, struct file *file)
 133 {
 134         const int key = ((u8 *) file_inode(file)->i_private)
 135                 - ((u8 *) NULL);
 136         return tomoyo_open_control(key, file);
 137 }
 138
 139 /**
 140  * tomoyo_release - close() for /sys/kernel/security/tomoyo/ interface.
 141  *
 142  * @file:  Pointer to "struct file".
 143  *
 144  */
 145 static int tomoyo_release(struct inode *inode, struct file *file)
 146 {
 147         tomoyo_close_control(file->private_data);
 148         return 0;
 149 }
 150
 151 /**
 152  * tomoyo_poll - poll() for /sys/kernel/security/tomoyo/ interface.
 153  *
 154  * @file: Pointer to "struct file".
 155  * @wait: Pointer to "poll_table". Maybe NULL.
 156  *
 157  * Returns EPOLLIN | EPOLLRDNORM | EPOLLOUT | EPOLLWRNORM if ready to read/write,
 158  * EPOLLOUT | EPOLLWRNORM otherwise.
 159  */
 160 static __poll_t tomoyo_poll(struct file *file, poll_table *wait)
 161 {
 162         return tomoyo_poll_control(file, wait);
 163 }
 164
 165 /**
 166  * tomoyo_read - read() for /sys/kernel/security/tomoyo/ interface.
 167  *
 168  * @file:  Pointer to "struct file".
 169  * @buf:   Pointer to buffer.
 170  * @count: Size of @buf.
 171  * @ppos:  Unused.
 172  *
 173  * Returns bytes read on success, negative value otherwise.
 174  */
 175 static ssize_t tomoyo_read(struct file *file, char __user *buf, size_t count,
 176                            loff_t *ppos)
 177 {
 178         return tomoyo_read_control(file->private_data, buf, count);
 179 }
 180
 181 /**
 182  * tomoyo_write - write() for /sys/kernel/security/tomoyo/ interface.
 183  *
 184  * @file:  Pointer to "struct file".
 185  * @buf:   Pointer to buffer.
 186  * @count: Size of @buf.
 187  * @ppos:  Unused.
 188  *
 189  * Returns @count on success, negative value otherwise.
 190  */
 191 static ssize_t tomoyo_write(struct file *file, const char __user *buf,
 192                             size_t count, loff_t *ppos)
 193 {
 194         return tomoyo_write_control(file->private_data, buf, count);
 195 }
 196
 197 /*
 198  * tomoyo_operations is a "struct file_operations" which is used for handling
 199  * /sys/kernel/security/tomoyo/ interface.
 200  *
 201  * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
 202  * See tomoyo_io_buffer for internals.
 203  */
 204 static const struct file_operations tomoyo_operations = {
 205         .open    = tomoyo_open,
 206         .release = tomoyo_release,
 207         .poll    = tomoyo_poll,
 208         .read    = tomoyo_read,
 209         .write   = tomoyo_write,
 210         .llseek  = noop_llseek,
 211 };
 212
 213 /**
 214  * tomoyo_create_entry - Create interface files under /sys/kernel/security/tomoyo/ directory.
 215  *
 216  * @name:   The name of the interface file.
 217  * @mode:   The permission of the interface file.
 218  * @parent: The parent directory.
 219  * @key:    Type of interface.
 220  *
 221  * Returns nothing.
 222  */
 223 static void __init tomoyo_create_entry(const char *name, const umode_t mode,
 224                                        struct dentry *parent, const u8 key)
 225 {
 226         securityfs_create_file(name, mode, parent, ((u8 *) NULL) + key,
 227                                &tomoyo_operations);
 228 }
 229
 230 /**
 231  * tomoyo_initerface_init - Initialize /sys/kernel/security/tomoyo/ interface.
 232  *
 233  * Returns 0.
 234  */
 235 static int __init tomoyo_initerface_init(void)
 236 {
 237         struct dentry *tomoyo_dir;
 238
 239         /* Don't create securityfs entries unless registered. */
 240         if (current_cred()->security != &tomoyo_kernel_domain)
 241                 return 0;
 242
 243         tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
 244         tomoyo_create_entry("query",            0600, tomoyo_dir,
 245                             TOMOYO_QUERY);
 246         tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
 247                             TOMOYO_DOMAINPOLICY);
 248         tomoyo_create_entry("exception_policy", 0600, tomoyo_dir,
 249                             TOMOYO_EXCEPTIONPOLICY);
 250         tomoyo_create_entry("audit",            0400, tomoyo_dir,
 251                             TOMOYO_AUDIT);
 252         tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
 253                             TOMOYO_PROCESS_STATUS);
 254         tomoyo_create_entry("stat",             0644, tomoyo_dir,
 255                             TOMOYO_STAT);
 256         tomoyo_create_entry("profile",          0600, tomoyo_dir,
 257                             TOMOYO_PROFILE);
 258         tomoyo_create_entry("manager",          0600, tomoyo_dir,
 259                             TOMOYO_MANAGER);
 260         tomoyo_create_entry("version",          0400, tomoyo_dir,
 261                             TOMOYO_VERSION);
 262         securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL,
 263                                &tomoyo_self_operations);
 264         tomoyo_load_builtin_policy();
 265         return 0;
 266 }
 267
 268 fs_initcall(tomoyo_initerface_init);