security/tomoyo/securityfs_if.c

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