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