ClabureDB: Classified Bug-Reports Database

   /*
    * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
    *
    *        This program is free software; you can redistribute it and/or modify
    *          it under the terms of the GNU General Public License as published by
    *        the Free Software Foundation, version 2.
    *
    * Authors:
    *         Casey Schaufler <casey@schaufler-ca.com>
   *         Ahmed S. Darwish <darwish.07@gmail.com>
   *
   * Special thanks to the authors of selinuxfs.
   *
   *        Karl MacMillan <kmacmillan@tresys.com>
   *        James Morris <jmorris@redhat.com>
   *
   */
  
  #include <linux/kernel.h>
  #include <linux/vmalloc.h>
  #include <linux/security.h>
  #include <linux/mutex.h>
  #include <net/netlabel.h>
  #include <net/cipso_ipv4.h>
  #include <linux/seq_file.h>
  #include <linux/ctype.h>
  #include <linux/audit.h>
  #include "smack.h"
  
  /*
   * smackfs pseudo filesystem.
   */
  
  enum smk_inos {
          SMK_ROOT_INO        = 2,
          SMK_LOAD        = 3,        /* load policy */
          SMK_CIPSO        = 4,        /* load label -> CIPSO mapping */
          SMK_DOI                = 5,        /* CIPSO DOI */
          SMK_DIRECT        = 6,        /* CIPSO level indicating direct label */
          SMK_AMBIENT        = 7,        /* internet ambient label */
          SMK_NLTYPE        = 8,        /* label scheme to use by default */
          SMK_ONLYCAP        = 9,        /* the only "capable" label */
  };
  
  /*
   * List locks
   */
  static DEFINE_MUTEX(smack_list_lock);
  static DEFINE_MUTEX(smack_cipso_lock);
  static DEFINE_MUTEX(smack_ambient_lock);
  
  /*
   * This is the "ambient" label for network traffic.
   * If it isn't somehow marked, use this.
   * It can be reset via smackfs/ambient
   */
  char *smack_net_ambient = smack_known_floor.smk_known;
  
  /*
   * This is the default packet marking scheme for network traffic.
   * It can be reset via smackfs/nltype
   */
  int smack_net_nltype = NETLBL_NLTYPE_CIPSOV4;
  
  /*
   * This is the level in a CIPSO header that indicates a
   * smack label is contained directly in the category set.
   * It can be reset via smackfs/direct
   */
  int smack_cipso_direct = SMACK_CIPSO_DIRECT_DEFAULT;
  
  /*
   * Unless a process is running with this label even
   * having CAP_MAC_OVERRIDE isn't enough to grant
   * privilege to violate MAC policy. If no label is
   * designated (the NULL case) capabilities apply to
   * everyone. It is expected that the hat (^) label
   * will be used if any label is used.
   */
  char *smack_onlycap;
  
  static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;
  struct smk_list_entry *smack_list;
  
  #define        SEQ_READ_FINISHED        1
  
  /*
   * Values for parsing cipso rules
   * SMK_DIGITLEN: Length of a digit field in a rule.
   * SMK_CIPSOMIN: Minimum possible cipso rule length.
   * SMK_CIPSOMAX: Maximum possible cipso rule length.
   */
  #define SMK_DIGITLEN 4
  #define SMK_CIPSOMIN (SMK_LABELLEN + 2 * SMK_DIGITLEN)
  #define SMK_CIPSOMAX (SMK_CIPSOMIN + SMACK_CIPSO_MAXCATNUM * SMK_DIGITLEN)
  
  /*
   * Values for parsing MAC rules
   * SMK_ACCESS: Maximum possible combination of access permissions
  * SMK_ACCESSLEN: Maximum length for a rule access field
  * SMK_LOADLEN: Smack rule length
  */
 #define SMK_ACCESS    "rwxa"
 #define SMK_ACCESSLEN (sizeof(SMK_ACCESS) - 1)
 #define SMK_LOADLEN   (SMK_LABELLEN + SMK_LABELLEN + SMK_ACCESSLEN)
 
 
 /*
  * Seq_file read operations for /smack/load
  */
 
 static void *load_seq_start(struct seq_file *s, loff_t *pos)
 {
         if (*pos == SEQ_READ_FINISHED)
                 return NULL;
 
         return smack_list;
 }
 
 static void *load_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         struct smk_list_entry *skp = ((struct smk_list_entry *) v)->smk_next;
 
         if (skp == NULL)
                 *pos = SEQ_READ_FINISHED;
 
         return skp;
 }
 
 static int load_seq_show(struct seq_file *s, void *v)
 {
         struct smk_list_entry *slp = (struct smk_list_entry *) v;
         struct smack_rule *srp = &slp->smk_rule;
 
         seq_printf(s, "%s %s", (char *)srp->smk_subject,
                    (char *)srp->smk_object);
 
         seq_putc(s, ' ');
 
         if (srp->smk_access & MAY_READ)
                 seq_putc(s, 'r');
         if (srp->smk_access & MAY_WRITE)
                 seq_putc(s, 'w');
         if (srp->smk_access & MAY_EXEC)
                 seq_putc(s, 'x');
         if (srp->smk_access & MAY_APPEND)
                 seq_putc(s, 'a');
         if (srp->smk_access == 0)
                 seq_putc(s, '-');
 
         seq_putc(s, '\n');
 
         return 0;
 }
 
 static void load_seq_stop(struct seq_file *s, void *v)
 {
         /* No-op */
 }
 
 static struct seq_operations load_seq_ops = {
         .start = load_seq_start,
         .next  = load_seq_next,
         .show  = load_seq_show,
         .stop  = load_seq_stop,
 };
 
 /**
  * smk_open_load - open() for /smack/load
  * @inode: inode structure representing file
  * @file: "load" file pointer
  *
  * For reading, use load_seq_* seq_file reading operations.
  */
 static int smk_open_load(struct inode *inode, struct file *file)
 {
         return seq_open(file, &load_seq_ops);
 }
 
 /**
  * smk_set_access - add a rule to the rule list
  * @srp: the new rule to add
  *
  * Looks through the current subject/object/access list for
  * the subject/object pair and replaces the access that was
  * there. If the pair isn't found add it with the specified
  * access.
  */
 static void smk_set_access(struct smack_rule *srp)
 {
         struct smk_list_entry *sp;
         struct smk_list_entry *newp;
 
         mutex_lock(&smack_list_lock);
 
         for (sp = smack_list; sp != NULL; sp = sp->smk_next)
                 if (sp->smk_rule.smk_subject == srp->smk_subject &&
                     sp->smk_rule.smk_object == srp->smk_object) {
                         sp->smk_rule.smk_access = srp->smk_access;
                         break;
                 }
 
         if (sp == NULL) {
                 newp = kzalloc(sizeof(struct smk_list_entry), GFP_KERNEL);
                 newp->smk_rule = *srp;
                 newp->smk_next = smack_list;
                 smack_list = newp;
         }
 
         mutex_unlock(&smack_list_lock);
 
         return;
 }
 
 /**
  * smk_write_load - write() for /smack/load
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  *
  * Get one smack access rule from above.
  * The format is exactly:
  *     char subject[SMK_LABELLEN]
  *     char object[SMK_LABELLEN]
  *     char access[SMK_ACCESSLEN]
  *
  * writes must be SMK_LABELLEN+SMK_LABELLEN+SMK_ACCESSLEN bytes.
  */
 static ssize_t smk_write_load(struct file *file, const char __user *buf,
                               size_t count, loff_t *ppos)
 {
         struct smack_rule rule;
         char *data;
         int rc = -EINVAL;
 
         /*
          * Must have privilege.
          * No partial writes.
          * Enough data must be present.
          */
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
         if (*ppos != 0)
                 return -EINVAL;
         if (count != SMK_LOADLEN)
                 return -EINVAL;
 
         data = kzalloc(count, GFP_KERNEL);
         if (data == NULL)
                 return -ENOMEM;
 
         if (copy_from_user(data, buf, count) != 0) {
                 rc = -EFAULT;
                 goto out;
         }
 
         rule.smk_subject = smk_import(data, 0);
         if (rule.smk_subject == NULL)
                 goto out;
 
         rule.smk_object = smk_import(data + SMK_LABELLEN, 0);
         if (rule.smk_object == NULL)
                 goto out;
 
         rule.smk_access = 0;
 
         switch (data[SMK_LABELLEN + SMK_LABELLEN]) {
         case '-':
                 break;
         case 'r':
         case 'R':
                 rule.smk_access |= MAY_READ;
                 break;
         default:
                 goto out;
         }
 
         switch (data[SMK_LABELLEN + SMK_LABELLEN + 1]) {
         case '-':
                 break;
         case 'w':
         case 'W':
                 rule.smk_access |= MAY_WRITE;
                 break;
         default:
                 goto out;
         }
 
         switch (data[SMK_LABELLEN + SMK_LABELLEN + 2]) {
         case '-':
                 break;
         case 'x':
         case 'X':
                 rule.smk_access |= MAY_EXEC;
                 break;
         default:
                 goto out;
         }
 
         switch (data[SMK_LABELLEN + SMK_LABELLEN + 3]) {
         case '-':
                 break;
         case 'a':
         case 'A':
                 rule.smk_access |= MAY_READ;
                 break;
         default:
                 goto out;
         }
 
         smk_set_access(&rule);
         rc = count;
 
 out:
         kfree(data);
         return rc;
 }
 
 static const struct file_operations smk_load_ops = {
         .open           = smk_open_load,
         .read                = seq_read,
         .llseek         = seq_lseek,
         .write                = smk_write_load,
         .release        = seq_release,
 };
 
 /**
  * smk_cipso_doi - initialize the CIPSO domain
  */
 static void smk_cipso_doi(void)
 {
         int rc;
         struct cipso_v4_doi *doip;
         struct netlbl_audit audit_info;
 
         audit_info.loginuid = audit_get_loginuid(current);
         audit_info.sessionid = audit_get_sessionid(current);
         audit_info.secid = smack_to_secid(current->security);
 
         rc = netlbl_cfg_map_del(NULL, &audit_info);
         if (rc != 0)
                 printk(KERN_WARNING "%s:%d remove rc = %d\n",
                        __func__, __LINE__, rc);
 
         doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL);
         if (doip == NULL)
                 panic("smack:  Failed to initialize cipso DOI.\n");
         doip->map.std = NULL;
         doip->doi = smk_cipso_doi_value;
         doip->type = CIPSO_V4_MAP_PASS;
         doip->tags[0] = CIPSO_V4_TAG_RBITMAP;
         for (rc = 1; rc < CIPSO_V4_TAG_MAXCNT; rc++)
                 doip->tags[rc] = CIPSO_V4_TAG_INVALID;
 
         rc = netlbl_cfg_cipsov4_add_map(doip, NULL, &audit_info);
         if (rc != 0) {
                 printk(KERN_WARNING "%s:%d add rc = %d\n",
                        __func__, __LINE__, rc);
                 kfree(doip);
         }
 }
 
 /**
  * smk_unlbl_ambient - initialize the unlabeled domain
  */
 static void smk_unlbl_ambient(char *oldambient)
 {
         int rc;
         struct netlbl_audit audit_info;
 
         audit_info.loginuid = audit_get_loginuid(current);
         audit_info.sessionid = audit_get_sessionid(current);
         audit_info.secid = smack_to_secid(current->security);
 
         if (oldambient != NULL) {
                 rc = netlbl_cfg_map_del(oldambient, &audit_info);
                 if (rc != 0)
                         printk(KERN_WARNING "%s:%d remove rc = %d\n",
                                __func__, __LINE__, rc);
         }
 
         rc = netlbl_cfg_unlbl_add_map(smack_net_ambient, &audit_info);
         if (rc != 0)
                 printk(KERN_WARNING "%s:%d add rc = %d\n",
                        __func__, __LINE__, rc);
 }
 
 /*
  * Seq_file read operations for /smack/cipso
  */
 
 static void *cipso_seq_start(struct seq_file *s, loff_t *pos)
 {
         if (*pos == SEQ_READ_FINISHED)
                 return NULL;
 
         return smack_known;
 }
 
 static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         struct smack_known *skp = ((struct smack_known *) v)->smk_next;
 
         /*
          * Omit labels with no associated cipso value
          */
         while (skp != NULL && !skp->smk_cipso)
                 skp = skp->smk_next;
 
         if (skp == NULL)
                 *pos = SEQ_READ_FINISHED;
 
         return skp;
 }
 
 /*
  * Print cipso labels in format:
  * label level[/cat[,cat]]
  */
 static int cipso_seq_show(struct seq_file *s, void *v)
 {
         struct smack_known *skp = (struct smack_known *) v;
         struct smack_cipso *scp = skp->smk_cipso;
         char *cbp;
         char sep = '/';
         int cat = 1;
         int i;
         unsigned char m;
 
         if (scp == NULL)
                 return 0;
 
         seq_printf(s, "%s %3d", (char *)&skp->smk_known, scp->smk_level);
 
         cbp = scp->smk_catset;
         for (i = 0; i < SMK_LABELLEN; i++)
                 for (m = 0x80; m != 0; m >>= 1) {
                         if (m & cbp[i]) {
                                 seq_printf(s, "%c%d", sep, cat);
                                 sep = ',';
                         }
                         cat++;
                 }
 
         seq_putc(s, '\n');
 
         return 0;
 }
 
 static void cipso_seq_stop(struct seq_file *s, void *v)
 {
         /* No-op */
 }
 
 static struct seq_operations cipso_seq_ops = {
         .start = cipso_seq_start,
         .stop  = cipso_seq_stop,
         .next  = cipso_seq_next,
         .show  = cipso_seq_show,
 };
 
 /**
  * smk_open_cipso - open() for /smack/cipso
  * @inode: inode structure representing file
  * @file: "cipso" file pointer
  *
  * Connect our cipso_seq_* operations with /smack/cipso
  * file_operations
  */
 static int smk_open_cipso(struct inode *inode, struct file *file)
 {
         return seq_open(file, &cipso_seq_ops);
 }
 
 /**
  * smk_write_cipso - write() for /smack/cipso
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Accepts only one cipso rule per write call.
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_cipso(struct file *file, const char __user *buf,
                                size_t count, loff_t *ppos)
 {
         struct smack_known *skp;
         struct smack_cipso *scp = NULL;
         char mapcatset[SMK_LABELLEN];
         int maplevel;
         int cat;
         int catlen;
         ssize_t rc = -EINVAL;
         char *data = NULL;
         char *rule;
         int ret;
         int i;
 
         /*
          * Must have privilege.
          * No partial writes.
          * Enough data must be present.
          */
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
         if (*ppos != 0)
                 return -EINVAL;
         if (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX)
                 return -EINVAL;
 
         data = kzalloc(count + 1, GFP_KERNEL);
         if (data == NULL)
                 return -ENOMEM;
 
         if (copy_from_user(data, buf, count) != 0) {
                 rc = -EFAULT;
                 goto unlockedout;
         }
 
         data[count] = '\0';
         rule = data;
         /*
          * Only allow one writer at a time. Writes should be
          * quite rare and small in any case.
          */
         mutex_lock(&smack_cipso_lock);
 
         skp = smk_import_entry(rule, 0);
         if (skp == NULL)
                 goto out;
 
         rule += SMK_LABELLEN;;
         ret = sscanf(rule, "%d", &maplevel);
         if (ret != 1 || maplevel > SMACK_CIPSO_MAXLEVEL)
                 goto out;
 
         rule += SMK_DIGITLEN;
         ret = sscanf(rule, "%d", &catlen);
         if (ret != 1 || catlen > SMACK_CIPSO_MAXCATNUM)
                 goto out;
 
         if (count != (SMK_CIPSOMIN + catlen * SMK_DIGITLEN))
                 goto out;
 
         memset(mapcatset, 0, sizeof(mapcatset));
 
         for (i = 0; i < catlen; i++) {
                 rule += SMK_DIGITLEN;
                 ret = sscanf(rule, "%d", &cat);
                 if (ret != 1 || cat > SMACK_CIPSO_MAXCATVAL)
                         goto out;
 
                 smack_catset_bit(cat, mapcatset);
         }
 
         if (skp->smk_cipso == NULL) {
                 scp = kzalloc(sizeof(struct smack_cipso), GFP_KERNEL);
                 if (scp == NULL) {
                         rc = -ENOMEM;
                         goto out;
                 }
         }
 
         spin_lock_bh(&skp->smk_cipsolock);
 
         if (scp == NULL)
                 scp = skp->smk_cipso;
         else
                 skp->smk_cipso = scp;
 
         scp->smk_level = maplevel;
         memcpy(scp->smk_catset, mapcatset, sizeof(mapcatset));
 
         spin_unlock_bh(&skp->smk_cipsolock);
 
         rc = count;
 out:
         mutex_unlock(&smack_cipso_lock);
 unlockedout:
         kfree(data);
         return rc;
 }
 
 static const struct file_operations smk_cipso_ops = {
         .open           = smk_open_cipso,
         .read                = seq_read,
         .llseek         = seq_lseek,
         .write                = smk_write_cipso,
         .release        = seq_release,
 };
 
 /**
  * smk_read_doi - read() for /smack/doi
  * @filp: file pointer, not actually used
  * @buf: where to put the result
  * @count: maximum to send along
  * @ppos: where to start
  *
  * Returns number of bytes read or error code, as appropriate
  */
 static ssize_t smk_read_doi(struct file *filp, char __user *buf,
                             size_t count, loff_t *ppos)
 {
         char temp[80];
         ssize_t rc;
 
         if (*ppos != 0)
                 return 0;
 
         sprintf(temp, "%d", smk_cipso_doi_value);
         rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
 
         return rc;
 }
 
 /**
  * smk_write_doi - write() for /smack/doi
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_doi(struct file *file, const char __user *buf,
                              size_t count, loff_t *ppos)
 {
         char temp[80];
         int i;
 
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count >= sizeof(temp) || count == 0)
                 return -EINVAL;
 
         if (copy_from_user(temp, buf, count) != 0)
                 return -EFAULT;
 
         temp[count] = '\0';
 
         if (sscanf(temp, "%d", &i) != 1)
                 return -EINVAL;
 
         smk_cipso_doi_value = i;
 
         smk_cipso_doi();
 
         return count;
 }
 
 static const struct file_operations smk_doi_ops = {
         .read                = smk_read_doi,
         .write                = smk_write_doi,
 };
 
 /**
  * smk_read_direct - read() for /smack/direct
  * @filp: file pointer, not actually used
  * @buf: where to put the result
  * @count: maximum to send along
  * @ppos: where to start
  *
  * Returns number of bytes read or error code, as appropriate
  */
 static ssize_t smk_read_direct(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
 {
         char temp[80];
         ssize_t rc;
 
         if (*ppos != 0)
                 return 0;
 
         sprintf(temp, "%d", smack_cipso_direct);
         rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
 
         return rc;
 }
 
 /**
  * smk_write_direct - write() for /smack/direct
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_direct(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char temp[80];
         int i;
 
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count >= sizeof(temp) || count == 0)
                 return -EINVAL;
 
         if (copy_from_user(temp, buf, count) != 0)
                 return -EFAULT;
 
         temp[count] = '\0';
 
         if (sscanf(temp, "%d", &i) != 1)
                 return -EINVAL;
 
         smack_cipso_direct = i;
 
         return count;
 }
 
 static const struct file_operations smk_direct_ops = {
         .read                = smk_read_direct,
         .write                = smk_write_direct,
 };
 
 /**
  * smk_read_ambient - read() for /smack/ambient
  * @filp: file pointer, not actually used
  * @buf: where to put the result
  * @cn: maximum to send along
  * @ppos: where to start
  *
  * Returns number of bytes read or error code, as appropriate
  */
 static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
                                 size_t cn, loff_t *ppos)
 {
         ssize_t rc;
         int asize;
 
         if (*ppos != 0)
                 return 0;
         /*
          * Being careful to avoid a problem in the case where
          * smack_net_ambient gets changed in midstream.
          */
         mutex_lock(&smack_ambient_lock);
 
         asize = strlen(smack_net_ambient) + 1;
 
         if (cn >= asize)
                 rc = simple_read_from_buffer(buf, cn, ppos,
                                              smack_net_ambient, asize);
         else
                 rc = -EINVAL;
 
         mutex_unlock(&smack_ambient_lock);
 
         return rc;
 }
 
 /**
  * smk_write_ambient - write() for /smack/ambient
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
                                  size_t count, loff_t *ppos)
 {
         char in[SMK_LABELLEN];
         char *oldambient;
         char *smack;
 
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count >= SMK_LABELLEN)
                 return -EINVAL;
 
         if (copy_from_user(in, buf, count) != 0)
                 return -EFAULT;
 
         smack = smk_import(in, count);
         if (smack == NULL)
                 return -EINVAL;
 
         mutex_lock(&smack_ambient_lock);
 
         oldambient = smack_net_ambient;
         smack_net_ambient = smack;
         smk_unlbl_ambient(oldambient);
 
         mutex_unlock(&smack_ambient_lock);
 
         return count;
 }
 
 static const struct file_operations smk_ambient_ops = {
         .read                = smk_read_ambient,
         .write                = smk_write_ambient,
 };
 
 /**
  * smk_read_onlycap - read() for /smack/onlycap
  * @filp: file pointer, not actually used
  * @buf: where to put the result
  * @cn: maximum to send along
  * @ppos: where to start
  *
  * Returns number of bytes read or error code, as appropriate
  */
 static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
                                 size_t cn, loff_t *ppos)
 {
         char *smack = "";
         ssize_t rc = -EINVAL;
         int asize;
 
         if (*ppos != 0)
                 return 0;
 
         if (smack_onlycap != NULL)
                 smack = smack_onlycap;
 
         asize = strlen(smack) + 1;
 
         if (cn >= asize)
                 rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);
 
         return rc;
 }
 
 /**
  * smk_write_onlycap - write() for /smack/onlycap
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
                                  size_t count, loff_t *ppos)
 {
         char in[SMK_LABELLEN];
         char *sp = current->security;
 
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
 
         /*
          * This can be done using smk_access() but is done
          * explicitly for clarity. The smk_access() implementation
          * would use smk_access(smack_onlycap, MAY_WRITE)
          */
         if (smack_onlycap != NULL && smack_onlycap != sp)
                 return -EPERM;
 
         if (count >= SMK_LABELLEN)
                 return -EINVAL;
 
         if (copy_from_user(in, buf, count) != 0)
                 return -EFAULT;
 
         /*
          * Should the null string be passed in unset the onlycap value.
          * This seems like something to be careful with as usually
          * smk_import only expects to return NULL for errors. It
          * is usually the case that a nullstring or "\n" would be
          * bad to pass to smk_import but in fact this is useful here.
          */
         smack_onlycap = smk_import(in, count);
 
         return count;
 }
 
 static const struct file_operations smk_onlycap_ops = {
         .read                = smk_read_onlycap,
         .write                = smk_write_onlycap,
 };
 
 struct option_names {
         int        o_number;
         char        *o_name;
         char        *o_alias;
 };
 
 static struct option_names netlbl_choices[] = {
         { NETLBL_NLTYPE_RIPSO,
                 NETLBL_NLTYPE_RIPSO_NAME,        "ripso" },
         { NETLBL_NLTYPE_CIPSOV4,
                 NETLBL_NLTYPE_CIPSOV4_NAME,        "cipsov4" },
         { NETLBL_NLTYPE_CIPSOV4,
                 NETLBL_NLTYPE_CIPSOV4_NAME,        "cipso" },
         { NETLBL_NLTYPE_CIPSOV6,
                 NETLBL_NLTYPE_CIPSOV6_NAME,        "cipsov6" },
         { NETLBL_NLTYPE_UNLABELED,
                 NETLBL_NLTYPE_UNLABELED_NAME,        "unlabeled" },
 };
 
 /**
  * smk_read_nltype - read() for /smack/nltype
  * @filp: file pointer, not actually used
  * @buf: where to put the result
  * @count: maximum to send along
  * @ppos: where to start
  *
  * Returns number of bytes read or error code, as appropriate
  */
 static ssize_t smk_read_nltype(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
 {
         char bound[40];
         ssize_t rc;
         int i;
 
         if (count < SMK_LABELLEN)
                 return -EINVAL;
 
         if (*ppos != 0)
                 return 0;
 
         sprintf(bound, "unknown");
 
         for (i = 0; i < ARRAY_SIZE(netlbl_choices); i++)
                 if (smack_net_nltype == netlbl_choices[i].o_number) {
                         sprintf(bound, "%s", netlbl_choices[i].o_name);
                         break;
                 }
 
         rc = simple_read_from_buffer(buf, count, ppos, bound, strlen(bound));
 
         return rc;
 }
 
 /**
  * smk_write_nltype - write() for /smack/nltype
  * @filp: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_nltype(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char bound[40];
         char *cp;
         int i;
 
         if (!capable(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count >= 40)
                 return -EINVAL;
 
         if (copy_from_user(bound, buf, count) != 0)
                 return -EFAULT;
 
         bound[count] = '\0';
         cp = strchr(bound, ' ');
         if (cp != NULL)
                 *cp = '\0';
         cp = strchr(bound, '\n');
         if (cp != NULL)
                 *cp = '\0';
 
         for (i = 0; i < ARRAY_SIZE(netlbl_choices); i++)
                 if (strcmp(bound, netlbl_choices[i].o_name) == 0 ||
                     strcmp(bound, netlbl_choices[i].o_alias) == 0) {
                         smack_net_nltype = netlbl_choices[i].o_number;
                         return count;
                 }
         /*
          * Not a valid choice.
          */
         return -EINVAL;
 }
 
 static const struct file_operations smk_nltype_ops = {
         .read                = smk_read_nltype,
         .write                = smk_write_nltype,
 };
 
 /**
  * smk_fill_super - fill the /smackfs superblock
  * @sb: the empty superblock
  * @data: unused
  * @silent: unused
  *
  * Fill in the well known entries for /smack
  *
  * Returns 0 on success, an error code on failure
  */
 static int smk_fill_super(struct super_block *sb, void *data, int silent)
 {
         int rc;
         struct inode *root_inode;

        static struct tree_descr smack_files[] = {
                [SMK_LOAD]        =
                        {"load", &smk_load_ops, S_IRUGO|S_IWUSR},
                [SMK_CIPSO]        =
                        {"cipso", &smk_cipso_ops, S_IRUGO|S_IWUSR},
                [SMK_DOI]        =
                        {"doi", &smk_doi_ops, S_IRUGO|S_IWUSR},
                [SMK_DIRECT]        =
                        {"direct", &smk_direct_ops, S_IRUGO|S_IWUSR},
                [SMK_AMBIENT]        =
                        {"ambient", &smk_ambient_ops, S_IRUGO|S_IWUSR},
                [SMK_NLTYPE]        =
                        {"nltype", &smk_nltype_ops, S_IRUGO|S_IWUSR},
                [SMK_ONLYCAP]        =
                        {"onlycap", &smk_onlycap_ops, S_IRUGO|S_IWUSR},
                /* last one */ {""}
        };

        rc = simple_fill_super(sb, SMACK_MAGIC, smack_files);
        if (rc != 0) {
                printk(KERN_ERR "%s failed %d while creating inodes\n",
                        __func__, rc);
                return rc;
        }

        root_inode = sb->s_root->d_inode;
        root_inode->i_security = new_inode_smack(smack_known_floor.smk_known);

        return 0;
}

/**
 * smk_get_sb - get the smackfs superblock
 * @fs_type: passed along without comment
 * @flags: passed along without comment
 * @dev_name: passed along without comment
 * @data: passed along without comment
 * @mnt: passed along without comment
 *
 * Just passes everything along.
 *
 * Returns what the lower level code does.
 */
static int smk_get_sb(struct file_system_type *fs_type,
                      int flags, const char *dev_name, void *data,
                      struct vfsmount *mnt)
{
        return get_sb_single(fs_type, flags, data, smk_fill_super, mnt);
}

static struct file_system_type smk_fs_type = {
        .name                = "smackfs",
        .get_sb                = smk_get_sb,
        .kill_sb        = kill_litter_super,
};

static struct vfsmount *smackfs_mount;

/**
 * init_smk_fs - get the smackfs superblock
 *
 * register the smackfs
 *
 * Do not register smackfs if Smack wasn't enabled
 * on boot. We can not put this method normally under the
 * smack_init() code path since the security subsystem get
 * initialized before the vfs caches.
 *
 * Returns true if we were not chosen on boot or if
 * we were chosen and filesystem registration succeeded.
 */
static int __init init_smk_fs(void)
{
        int err;

        if (!security_module_enable(&smack_ops))
                return 0;

        err = register_filesystem(&smk_fs_type);
        if (!err) {
                smackfs_mount = kern_mount(&smk_fs_type);
                if (IS_ERR(smackfs_mount)) {
                        printk(KERN_ERR "smackfs:  could not mount!\n");
                        err = PTR_ERR(smackfs_mount);
                        smackfs_mount = NULL;
                }
        }

        smk_cipso_doi();
        smk_unlbl_ambient(NULL);

        return err;
}

__initcall(init_smk_fs);