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 **blob;
  75                                         struct tomoyo_domain_info *old_domain;
  76
  77                                         blob = tomoyo_cred(cred);
  78                                         old_domain = *blob;
  79                                         *blob = new_domain;
  80                                         atomic_inc(&new_domain->users);
  81                                         atomic_dec(&old_domain->users);
  82                                         commit_creds(cred);
  83                                         error = 0;
  84                                 }
  85                         }
  86                 }
  87                 tomoyo_read_unlock(idx);
  88         } else
  89                 error = -EINVAL;
  90         kfree(data);
  91         return error ? error : count;
  92 }
  93
  94 /**
  95  * tomoyo_read_self - read() for /sys/kernel/security/tomoyo/self_domain interface.
  96  *
  97  * @file:  Pointer to "struct file".
  98  * @buf:   Domainname which current thread belongs to.
  99  * @count: Size of @buf.
 100  * @ppos:  Bytes read by now.
 101  *
 102  * Returns read size on success, negative value otherwise.
 103  */
 104 static ssize_t tomoyo_read_self(struct file *file, char __user *buf,
 105                                 size_t count, loff_t *ppos)
 106 {
 107         const char *domain = tomoyo_domain()->domainname->name;
 108         loff_t len = strlen(domain);
 109         loff_t pos = *ppos;
 110         if (pos >= len || !count)
 111                 return 0;
 112         len -= pos;
 113         if (count < len)
 114                 len = count;
 115         if (copy_to_user(buf, domain + pos, len))
 116                 return -EFAULT;
 117         *ppos += len;
 118         return len;
 119 }
 120
 121 /* Operations for /sys/kernel/security/tomoyo/self_domain interface. */
 122 static const struct file_operations tomoyo_self_operations = {
 123         .write = tomoyo_write_self,
 124         .read  = tomoyo_read_self,
 125 };
 126
 127 /**
 128  * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
 129  *
 130  * @inode: Pointer to "struct inode".
 131  * @file:  Pointer to "struct file".
 132  *
 133  * Returns 0 on success, negative value otherwise.
 134  */
 135 static int tomoyo_open(struct inode *inode, struct file *file)
 136 {
 137         const int key = ((u8 *) file_inode(file)->i_private)
 138                 - ((u8 *) NULL);
 139         return tomoyo_open_control(key, file);
 140 }
 141
 142 /**
 143  * tomoyo_release - close() for /sys/kernel/security/tomoyo/ interface.
 144  *
 145  * @file:  Pointer to "struct file".
 146  *
 147  */
 148 static int tomoyo_release(struct inode *inode, struct file *file)
 149 {
 150         tomoyo_close_control(file->private_data);
 151         return 0;
 152 }
 153
 154 /**
 155  * tomoyo_poll - poll() for /sys/kernel/security/tomoyo/ interface.
 156  *
 157  * @file: Pointer to "struct file".
 158  * @wait: Pointer to "poll_table". Maybe NULL.
 159  *
 160  * Returns EPOLLIN | EPOLLRDNORM | EPOLLOUT | EPOLLWRNORM if ready to read/write,
 161  * EPOLLOUT | EPOLLWRNORM otherwise.
 162  */
 163 static __poll_t tomoyo_poll(struct file *file, poll_table *wait)
 164 {
 165         return tomoyo_poll_control(file, wait);
 166 }
 167
 168 /**
 169  * tomoyo_read - read() for /sys/kernel/security/tomoyo/ interface.
 170  *
 171  * @file:  Pointer to "struct file".
 172  * @buf:   Pointer to buffer.
 173  * @count: Size of @buf.
 174  * @ppos:  Unused.
 175  *
 176  * Returns bytes read on success, negative value otherwise.
 177  */
 178 static ssize_t tomoyo_read(struct file *file, char __user *buf, size_t count,
 179                            loff_t *ppos)
 180 {
 181         return tomoyo_read_control(file->private_data, buf, count);
 182 }
 183
 184 /**
 185  * tomoyo_write - write() for /sys/kernel/security/tomoyo/ interface.
 186  *
 187  * @file:  Pointer to "struct file".
 188  * @buf:   Pointer to buffer.
 189  * @count: Size of @buf.
 190  * @ppos:  Unused.
 191  *
 192  * Returns @count on success, negative value otherwise.
 193  */
 194 static ssize_t tomoyo_write(struct file *file, const char __user *buf,
 195                             size_t count, loff_t *ppos)
 196 {
 197         return tomoyo_write_control(file->private_data, buf, count);
 198 }
 199
 200 /*
 201  * tomoyo_operations is a "struct file_operations" which is used for handling
 202  * /sys/kernel/security/tomoyo/ interface.
 203  *
 204  * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
 205  * See tomoyo_io_buffer for internals.
 206  */
 207 static const struct file_operations tomoyo_operations = {
 208         .open    = tomoyo_open,
 209         .release = tomoyo_release,
 210         .poll    = tomoyo_poll,
 211         .read    = tomoyo_read,
 212         .write   = tomoyo_write,
 213         .llseek  = noop_llseek,
 214 };
 215
 216 /**
 217  * tomoyo_create_entry - Create interface files under /sys/kernel/security/tomoyo/ directory.
 218  *
 219  * @name:   The name of the interface file.
 220  * @mode:   The permission of the interface file.
 221  * @parent: The parent directory.
 222  * @key:    Type of interface.
 223  *
 224  * Returns nothing.
 225  */
 226 static void __init tomoyo_create_entry(const char *name, const umode_t mode,
 227                                        struct dentry *parent, const u8 key)
 228 {
 229         securityfs_create_file(name, mode, parent, ((u8 *) NULL) + key,
 230                                &tomoyo_operations);
 231 }
 232
 233 /**
 234  * tomoyo_initerface_init - Initialize /sys/kernel/security/tomoyo/ interface.
 235  *
 236  * Returns 0.
 237  */
 238 static int __init tomoyo_initerface_init(void)
 239 {
 240         struct tomoyo_domain_info *domain;
 241         struct dentry *tomoyo_dir;
 242
 243         if (!tomoyo_enabled)
 244                 return 0;
 245         domain = tomoyo_domain();
 246         /* Don't create securityfs entries unless registered. */
 247         if (domain != &tomoyo_kernel_domain)
 248                 return 0;
 249
 250         tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
 251         tomoyo_create_entry("query",            0600, tomoyo_dir,
 252                             TOMOYO_QUERY);
 253         tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
 254                             TOMOYO_DOMAINPOLICY);
 255         tomoyo_create_entry("exception_policy", 0600, tomoyo_dir,
 256                             TOMOYO_EXCEPTIONPOLICY);
 257         tomoyo_create_entry("audit",            0400, tomoyo_dir,
 258                             TOMOYO_AUDIT);
 259         tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
 260                             TOMOYO_PROCESS_STATUS);
 261         tomoyo_create_entry("stat",             0644, tomoyo_dir,
 262                             TOMOYO_STAT);
 263         tomoyo_create_entry("profile",          0600, tomoyo_dir,
 264                             TOMOYO_PROFILE);
 265         tomoyo_create_entry("manager",          0600, tomoyo_dir,
 266                             TOMOYO_MANAGER);
 267         tomoyo_create_entry("version",          0400, tomoyo_dir,
 268                             TOMOYO_VERSION);
 269         securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL,
 270                                &tomoyo_self_operations);
 271         tomoyo_load_builtin_policy();
 272         return 0;
 273 }
 274
 275 fs_initcall(tomoyo_initerface_init);