TOMOYO Linux Cross Reference
Linux/security/smack/smackfs.c

   // SPDX-License-Identifier: GPL-2.0-only
   /*
    * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
    *
    * 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 <linux/slab.h>
  #include <net/net_namespace.h>
  #include <net/cipso_ipv4.h>
  #include <linux/seq_file.h>
  #include <linux/ctype.h>
  #include <linux/audit.h>
  #include <linux/magic.h>
  #include <linux/mount.h>
  #include <linux/fs_context.h>
  #include "smack.h"
  
  #define BEBITS  (sizeof(__be32) * 8)
  /*
   * 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_NET4ADDR    = 8,    /* single label hosts */
          SMK_ONLYCAP     = 9,    /* the only "capable" label */
          SMK_LOGGING     = 10,   /* logging */
          SMK_LOAD_SELF   = 11,   /* task specific rules */
          SMK_ACCESSES    = 12,   /* access policy */
          SMK_MAPPED      = 13,   /* CIPSO level indicating mapped label */
          SMK_LOAD2       = 14,   /* load policy with long labels */
          SMK_LOAD_SELF2  = 15,   /* load task specific rules with long labels */
          SMK_ACCESS2     = 16,   /* make an access check with long labels */
          SMK_CIPSO2      = 17,   /* load long label -> CIPSO mapping */
          SMK_REVOKE_SUBJ = 18,   /* set rules with subject label to '-' */
          SMK_CHANGE_RULE = 19,   /* change or add rules (long labels) */
          SMK_SYSLOG      = 20,   /* change syslog label) */
          SMK_PTRACE      = 21,   /* set ptrace rule */
  #ifdef CONFIG_SECURITY_SMACK_BRINGUP
          SMK_UNCONFINED  = 22,   /* define an unconfined label */
  #endif
  #if IS_ENABLED(CONFIG_IPV6)
          SMK_NET6ADDR    = 23,   /* single label IPv6 hosts */
  #endif /* CONFIG_IPV6 */
          SMK_RELABEL_SELF = 24, /* relabel possible without CAP_MAC_ADMIN */
  };
  
  /*
   * List locks
   */
  static DEFINE_MUTEX(smack_cipso_lock);
  static DEFINE_MUTEX(smack_ambient_lock);
  static DEFINE_MUTEX(smk_net4addr_lock);
  #if IS_ENABLED(CONFIG_IPV6)
  static DEFINE_MUTEX(smk_net6addr_lock);
  #endif /* CONFIG_IPV6 */
  
  /*
   * This is the "ambient" label for network traffic.
   * If it isn't somehow marked, use this.
   * It can be reset via smackfs/ambient
   */
  struct smack_known *smack_net_ambient;
  
  /*
   * 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;
  
  /*
   * This is the level in a CIPSO header that indicates a
   * secid is contained directly in the category set.
   * It can be reset via smackfs/mapped
   */
  int smack_cipso_mapped = SMACK_CIPSO_MAPPED_DEFAULT;
  
  #ifdef CONFIG_SECURITY_SMACK_BRINGUP
  /*
   * Allow one label to be unconfined. This is for
   * debugging and application bring-up purposes only.
  * It is bad and wrong, but everyone seems to expect
  * to have it.
  */
 struct smack_known *smack_unconfined;
 #endif
 
 /*
  * If this value is set restrict syslog use to the label specified.
  * It can be reset via smackfs/syslog
  */
 struct smack_known *smack_syslog_label;
 
 /*
  * Ptrace current rule
  * SMACK_PTRACE_DEFAULT    regular smack ptrace rules (/proc based)
  * SMACK_PTRACE_EXACT      labels must match, but can be overriden with
  *                         CAP_SYS_PTRACE
  * SMACK_PTRACE_DRACONIAN  labels must match, CAP_SYS_PTRACE has no effect
  */
 int smack_ptrace_rule = SMACK_PTRACE_DEFAULT;
 
 /*
  * Certain IP addresses may be designated as single label hosts.
  * Packets are sent there unlabeled, but only from tasks that
  * can write to the specified label.
  */
 
 LIST_HEAD(smk_net4addr_list);
 #if IS_ENABLED(CONFIG_IPV6)
 LIST_HEAD(smk_net6addr_list);
 #endif /* CONFIG_IPV6 */
 
 /*
  * Rule lists are maintained for each label.
  */
 struct smack_parsed_rule {
         struct smack_known      *smk_subject;
         struct smack_known      *smk_object;
         int                     smk_access1;
         int                     smk_access2;
 };
 
 static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;
 
 /*
  * 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_OACCESS     "rwxa"
 #define SMK_ACCESS      "rwxatl"
 #define SMK_OACCESSLEN  (sizeof(SMK_OACCESS) - 1)
 #define SMK_ACCESSLEN   (sizeof(SMK_ACCESS) - 1)
 #define SMK_OLOADLEN    (SMK_LABELLEN + SMK_LABELLEN + SMK_OACCESSLEN)
 #define SMK_LOADLEN     (SMK_LABELLEN + SMK_LABELLEN + SMK_ACCESSLEN)
 
 /*
  * Stricly for CIPSO level manipulation.
  * Set the category bit number in a smack label sized buffer.
  */
 static inline void smack_catset_bit(unsigned int cat, char *catsetp)
 {
         if (cat == 0 || cat > (SMK_CIPSOLEN * 8))
                 return;
 
         catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
 }
 
 /**
  * smk_netlabel_audit_set - fill a netlbl_audit struct
  * @nap: structure to fill
  */
 static void smk_netlabel_audit_set(struct netlbl_audit *nap)
 {
         struct smack_known *skp = smk_of_current();
 
         nap->loginuid = audit_get_loginuid(current);
         nap->sessionid = audit_get_sessionid(current);
         nap->secid = skp->smk_secid;
 }
 
 /*
  * Value for parsing single label host rules
  * "1.2.3.4 X"
  */
 #define SMK_NETLBLADDRMIN       9
 
 /**
  * smk_set_access - add a rule to the rule list or replace an old rule
  * @srp: the rule to add or replace
  * @rule_list: the list of rules
  * @rule_lock: the rule list lock
  *
  * 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.
  *
  * Returns 0 if nothing goes wrong or -ENOMEM if it fails
  * during the allocation of the new pair to add.
  */
 static int smk_set_access(struct smack_parsed_rule *srp,
                                 struct list_head *rule_list,
                                 struct mutex *rule_lock)
 {
         struct smack_rule *sp;
         int found = 0;
         int rc = 0;
 
         mutex_lock(rule_lock);
 
         /*
          * Because the object label is less likely to match
          * than the subject label check it first
          */
         list_for_each_entry_rcu(sp, rule_list, list) {
                 if (sp->smk_object == srp->smk_object &&
                     sp->smk_subject == srp->smk_subject) {
                         found = 1;
                         sp->smk_access |= srp->smk_access1;
                         sp->smk_access &= ~srp->smk_access2;
                         break;
                 }
         }
 
         if (found == 0) {
                 sp = kmem_cache_zalloc(smack_rule_cache, GFP_KERNEL);
                 if (sp == NULL) {
                         rc = -ENOMEM;
                         goto out;
                 }
 
                 sp->smk_subject = srp->smk_subject;
                 sp->smk_object = srp->smk_object;
                 sp->smk_access = srp->smk_access1 & ~srp->smk_access2;
 
                 list_add_rcu(&sp->list, rule_list);
         }
 
 out:
         mutex_unlock(rule_lock);
         return rc;
 }
 
 /**
  * smk_perm_from_str - parse smack accesses from a text string
  * @string: a text string that contains a Smack accesses code
  *
  * Returns an integer with respective bits set for specified accesses.
  */
 static int smk_perm_from_str(const char *string)
 {
         int perm = 0;
         const char *cp;
 
         for (cp = string; ; cp++)
                 switch (*cp) {
                 case '-':
                         break;
                 case 'r':
                 case 'R':
                         perm |= MAY_READ;
                         break;
                 case 'w':
                 case 'W':
                         perm |= MAY_WRITE;
                         break;
                 case 'x':
                 case 'X':
                         perm |= MAY_EXEC;
                         break;
                 case 'a':
                 case 'A':
                         perm |= MAY_APPEND;
                         break;
                 case 't':
                 case 'T':
                         perm |= MAY_TRANSMUTE;
                         break;
                 case 'l':
                 case 'L':
                         perm |= MAY_LOCK;
                         break;
                 case 'b':
                 case 'B':
                         perm |= MAY_BRINGUP;
                         break;
                 default:
                         return perm;
                 }
 }
 
 /**
  * smk_fill_rule - Fill Smack rule from strings
  * @subject: subject label string
  * @object: object label string
  * @access1: access string
  * @access2: string with permissions to be removed
  * @rule: Smack rule
  * @import: if non-zero, import labels
  * @len: label length limit
  *
  * Returns 0 on success, appropriate error code on failure.
  */
 static int smk_fill_rule(const char *subject, const char *object,
                                 const char *access1, const char *access2,
                                 struct smack_parsed_rule *rule, int import,
                                 int len)
 {
         const char *cp;
         struct smack_known *skp;
 
         if (import) {
                 rule->smk_subject = smk_import_entry(subject, len);
                 if (IS_ERR(rule->smk_subject))
                         return PTR_ERR(rule->smk_subject);
 
                 rule->smk_object = smk_import_entry(object, len);
                 if (IS_ERR(rule->smk_object))
                         return PTR_ERR(rule->smk_object);
         } else {
                 cp = smk_parse_smack(subject, len);
                 if (IS_ERR(cp))
                         return PTR_ERR(cp);
                 skp = smk_find_entry(cp);
                 kfree(cp);
                 if (skp == NULL)
                         return -ENOENT;
                 rule->smk_subject = skp;
 
                 cp = smk_parse_smack(object, len);
                 if (IS_ERR(cp))
                         return PTR_ERR(cp);
                 skp = smk_find_entry(cp);
                 kfree(cp);
                 if (skp == NULL)
                         return -ENOENT;
                 rule->smk_object = skp;
         }
 
         rule->smk_access1 = smk_perm_from_str(access1);
         if (access2)
                 rule->smk_access2 = smk_perm_from_str(access2);
         else
                 rule->smk_access2 = ~rule->smk_access1;
 
         return 0;
 }
 
 /**
  * smk_parse_rule - parse Smack rule from load string
  * @data: string to be parsed whose size is SMK_LOADLEN
  * @rule: Smack rule
  * @import: if non-zero, import labels
  *
  * Returns 0 on success, -1 on errors.
  */
 static int smk_parse_rule(const char *data, struct smack_parsed_rule *rule,
                                 int import)
 {
         int rc;
 
         rc = smk_fill_rule(data, data + SMK_LABELLEN,
                            data + SMK_LABELLEN + SMK_LABELLEN, NULL, rule,
                            import, SMK_LABELLEN);
         return rc;
 }
 
 /**
  * smk_parse_long_rule - parse Smack rule from rule string
  * @data: string to be parsed, null terminated
  * @rule: Will be filled with Smack parsed rule
  * @import: if non-zero, import labels
  * @tokens: number of substrings expected in data
  *
  * Returns number of processed bytes on success, -ERRNO on failure.
  */
 static ssize_t smk_parse_long_rule(char *data, struct smack_parsed_rule *rule,
                                 int import, int tokens)
 {
         ssize_t cnt = 0;
         char *tok[4];
         int rc;
         int i;
 
         /*
          * Parsing the rule in-place, filling all white-spaces with '\0'
          */
         for (i = 0; i < tokens; ++i) {
                 while (isspace(data[cnt]))
                         data[cnt++] = '\0';
 
                 if (data[cnt] == '\0')
                         /* Unexpected end of data */
                         return -EINVAL;
 
                 tok[i] = data + cnt;
 
                 while (data[cnt] && !isspace(data[cnt]))
                         ++cnt;
         }
         while (isspace(data[cnt]))
                 data[cnt++] = '\0';
 
         while (i < 4)
                 tok[i++] = NULL;
 
         rc = smk_fill_rule(tok[0], tok[1], tok[2], tok[3], rule, import, 0);
         return rc == 0 ? cnt : rc;
 }
 
 #define SMK_FIXED24_FMT 0       /* Fixed 24byte label format */
 #define SMK_LONG_FMT    1       /* Variable long label format */
 #define SMK_CHANGE_FMT  2       /* Rule modification format */
 /**
  * smk_write_rules_list - write() for any /smack rule file
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  * @rule_list: the list of rules to write to
  * @rule_lock: lock for the rule list
  * @format: /smack/load or /smack/load2 or /smack/change-rule format.
  *
  * Get one smack access rule from above.
  * The format for SMK_LONG_FMT is:
  *      "subject<whitespace>object<whitespace>access[<whitespace>...]"
  * The format for SMK_FIXED24_FMT is exactly:
  *      "subject                 object                  rwxat"
  * The format for SMK_CHANGE_FMT is:
  *      "subject<whitespace>object<whitespace>
  *       acc_enable<whitespace>acc_disable[<whitespace>...]"
  */
 static ssize_t smk_write_rules_list(struct file *file, const char __user *buf,
                                         size_t count, loff_t *ppos,
                                         struct list_head *rule_list,
                                         struct mutex *rule_lock, int format)
 {
         struct smack_parsed_rule rule;
         char *data;
         int rc;
         int trunc = 0;
         int tokens;
         ssize_t cnt = 0;
 
         /*
          * No partial writes.
          * Enough data must be present.
          */
         if (*ppos != 0)
                 return -EINVAL;
 
         if (format == SMK_FIXED24_FMT) {
                 /*
                  * Minor hack for backward compatibility
                  */
                 if (count < SMK_OLOADLEN || count > SMK_LOADLEN)
                         return -EINVAL;
         } else {
                 if (count >= PAGE_SIZE) {
                         count = PAGE_SIZE - 1;
                         trunc = 1;
                 }
         }
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         /*
          * In case of parsing only part of user buf,
          * avoid having partial rule at the data buffer
          */
         if (trunc) {
                 while (count > 0 && (data[count - 1] != '\n'))
                         --count;
                 if (count == 0) {
                         rc = -EINVAL;
                         goto out;
                 }
         }
 
         data[count] = '\0';
         tokens = (format == SMK_CHANGE_FMT ? 4 : 3);
         while (cnt < count) {
                 if (format == SMK_FIXED24_FMT) {
                         rc = smk_parse_rule(data, &rule, 1);
                         if (rc < 0)
                                 goto out;
                         cnt = count;
                 } else {
                         rc = smk_parse_long_rule(data + cnt, &rule, 1, tokens);
                         if (rc < 0)
                                 goto out;
                         if (rc == 0) {
                                 rc = -EINVAL;
                                 goto out;
                         }
                         cnt += rc;
                 }
 
                 if (rule_list == NULL)
                         rc = smk_set_access(&rule, &rule.smk_subject->smk_rules,
                                 &rule.smk_subject->smk_rules_lock);
                 else
                         rc = smk_set_access(&rule, rule_list, rule_lock);
 
                 if (rc)
                         goto out;
         }
 
         rc = cnt;
 out:
         kfree(data);
         return rc;
 }
 
 /*
  * Core logic for smackfs seq list operations.
  */
 
 static void *smk_seq_start(struct seq_file *s, loff_t *pos,
                                 struct list_head *head)
 {
         struct list_head *list;
         int i = *pos;
 
         rcu_read_lock();
         for (list = rcu_dereference(list_next_rcu(head));
                 list != head;
                 list = rcu_dereference(list_next_rcu(list))) {
                 if (i-- == 0)
                         return list;
         }
 
         return NULL;
 }
 
 static void *smk_seq_next(struct seq_file *s, void *v, loff_t *pos,
                                 struct list_head *head)
 {
         struct list_head *list = v;
 
         ++*pos;
         list = rcu_dereference(list_next_rcu(list));
 
         return (list == head) ? NULL : list;
 }
 
 static void smk_seq_stop(struct seq_file *s, void *v)
 {
         rcu_read_unlock();
 }
 
 static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 {
         /*
          * Don't show any rules with label names too long for
          * interface file (/smack/load or /smack/load2)
          * because you should expect to be able to write
          * anything you read back.
          */
         if (strlen(srp->smk_subject->smk_known) >= max ||
             strlen(srp->smk_object->smk_known) >= max)
                 return;
 
         if (srp->smk_access == 0)
                 return;
 
         seq_printf(s, "%s %s",
                    srp->smk_subject->smk_known,
                    srp->smk_object->smk_known);
 
         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 & MAY_TRANSMUTE)
                 seq_putc(s, 't');
         if (srp->smk_access & MAY_LOCK)
                 seq_putc(s, 'l');
         if (srp->smk_access & MAY_BRINGUP)
                 seq_putc(s, 'b');
 
         seq_putc(s, '\n');
 }
 
 /*
  * Seq_file read operations for /smack/load
  */
 
 static void *load2_seq_start(struct seq_file *s, loff_t *pos)
 {
         return smk_seq_start(s, pos, &smack_known_list);
 }
 
 static void *load2_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         return smk_seq_next(s, v, pos, &smack_known_list);
 }
 
 static int load_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smack_rule *srp;
         struct smack_known *skp =
                 list_entry_rcu(list, struct smack_known, list);
 
         list_for_each_entry_rcu(srp, &skp->smk_rules, list)
                 smk_rule_show(s, srp, SMK_LABELLEN);
 
         return 0;
 }
 
 static const struct seq_operations load_seq_ops = {
         .start = load2_seq_start,
         .next  = load2_seq_next,
         .show  = load_seq_show,
         .stop  = smk_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_write_load - write() for /smack/load
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  *
  */
 static ssize_t smk_write_load(struct file *file, const char __user *buf,
                               size_t count, loff_t *ppos)
 {
         /*
          * Must have privilege.
          * No partial writes.
          * Enough data must be present.
          */
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         return smk_write_rules_list(file, buf, count, ppos, NULL, NULL,
                                     SMK_FIXED24_FMT);
 }
 
 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 nai;
 
         smk_netlabel_audit_set(&nai);
 
         rc = netlbl_cfg_map_del(NULL, PF_INET, NULL, NULL, &nai);
         if (rc != 0)
                 printk(KERN_WARNING "%s:%d remove rc = %d\n",
                        __func__, __LINE__, rc);
 
         doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL | __GFP_NOFAIL);
         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(doip, &nai);
         if (rc != 0) {
                 printk(KERN_WARNING "%s:%d cipso add rc = %d\n",
                        __func__, __LINE__, rc);
                 kfree(doip);
                 return;
         }
         rc = netlbl_cfg_cipsov4_map_add(doip->doi, NULL, NULL, NULL, &nai);
         if (rc != 0) {
                 printk(KERN_WARNING "%s:%d map add rc = %d\n",
                        __func__, __LINE__, rc);
                 netlbl_cfg_cipsov4_del(doip->doi, &nai);
                 return;
         }
 }
 
 /**
  * smk_unlbl_ambient - initialize the unlabeled domain
  * @oldambient: previous domain string
  */
 static void smk_unlbl_ambient(char *oldambient)
 {
         int rc;
         struct netlbl_audit nai;
 
         smk_netlabel_audit_set(&nai);
 
         if (oldambient != NULL) {
                 rc = netlbl_cfg_map_del(oldambient, PF_INET, NULL, NULL, &nai);
                 if (rc != 0)
                         printk(KERN_WARNING "%s:%d remove rc = %d\n",
                                __func__, __LINE__, rc);
         }
         if (smack_net_ambient == NULL)
                 smack_net_ambient = &smack_known_floor;
 
         rc = netlbl_cfg_unlbl_map_add(smack_net_ambient->smk_known, PF_INET,
                                       NULL, NULL, &nai);
         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)
 {
         return smk_seq_start(s, pos, &smack_known_list);
 }
 
 static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         return smk_seq_next(s, v, pos, &smack_known_list);
 }
 
 /*
  * Print cipso labels in format:
  * label level[/cat[,cat]]
  */
 static int cipso_seq_show(struct seq_file *s, void *v)
 {
         struct list_head  *list = v;
         struct smack_known *skp =
                 list_entry_rcu(list, struct smack_known, list);
         struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
         char sep = '/';
         int i;
 
         /*
          * Don't show a label that could not have been set using
          * /smack/cipso. This is in support of the notion that
          * anything read from /smack/cipso ought to be writeable
          * to /smack/cipso.
          *
          * /smack/cipso2 should be used instead.
          */
         if (strlen(skp->smk_known) >= SMK_LABELLEN)
                 return 0;
 
         seq_printf(s, "%s %3d", skp->smk_known, skp->smk_netlabel.attr.mls.lvl);
 
         for (i = netlbl_catmap_walk(cmp, 0); i >= 0;
              i = netlbl_catmap_walk(cmp, i + 1)) {
                 seq_printf(s, "%c%d", sep, i);
                 sep = ',';
         }
 
         seq_putc(s, '\n');
 
         return 0;
 }
 
 static const struct seq_operations cipso_seq_ops = {
         .start = cipso_seq_start,
         .next  = cipso_seq_next,
         .show  = cipso_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * 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_set_cipso - do the work for write() for cipso and cipso2
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  * @format: /smack/cipso or /smack/cipso2
  *
  * Accepts only one cipso rule per write call.
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos, int format)
 {
         struct netlbl_lsm_catmap *old_cat, *new_cat = NULL;
         struct smack_known *skp;
         struct netlbl_lsm_secattr ncats;
         char mapcatset[SMK_CIPSOLEN];
         int maplevel;
         unsigned 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 (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
         if (*ppos != 0)
                 return -EINVAL;
         if (format == SMK_FIXED24_FMT &&
             (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX))
                 return -EINVAL;
         if (count > PAGE_SIZE)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         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 (IS_ERR(skp)) {
                 rc = PTR_ERR(skp);
                 goto out;
         }
 
         if (format == SMK_FIXED24_FMT)
                 rule += SMK_LABELLEN;
         else
                 rule += strlen(skp->smk_known) + 1;
 
         if (rule > data + count) {
                 rc = -EOVERFLOW;
                 goto out;
         }
 
         ret = sscanf(rule, "%d", &maplevel);
         if (ret != 1 || maplevel < 0 || maplevel > SMACK_CIPSO_MAXLEVEL)
                 goto out;
 
         rule += SMK_DIGITLEN;
         if (rule > data + count) {
                 rc = -EOVERFLOW;
                 goto out;
         }
 
         ret = sscanf(rule, "%d", &catlen);
         if (ret != 1 || catlen < 0 || catlen > SMACK_CIPSO_MAXCATNUM)
                 goto out;
 
         if (format == SMK_FIXED24_FMT &&
             count != (SMK_CIPSOMIN + catlen * SMK_DIGITLEN))
                 goto out;
 
         memset(mapcatset, 0, sizeof(mapcatset));
 
         for (i = 0; i < catlen; i++) {
                 rule += SMK_DIGITLEN;
                 if (rule > data + count) {
                         rc = -EOVERFLOW;
                         goto out;
                 }
                 ret = sscanf(rule, "%u", &cat);
                 if (ret != 1 || cat > SMACK_CIPSO_MAXCATNUM)
                         goto out;
 
                 smack_catset_bit(cat, mapcatset);
         }
         ncats.flags = 0;
         if (catlen == 0) {
                 ncats.attr.mls.cat = NULL;
                 ncats.attr.mls.lvl = maplevel;
                 new_cat = netlbl_catmap_alloc(GFP_ATOMIC);
                 if (new_cat)
                         new_cat->next = ncats.attr.mls.cat;
                 ncats.attr.mls.cat = new_cat;
                 skp->smk_netlabel.flags &= ~(1U << 3);
                 rc = 0;
         } else {
                 rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN);
         }
         if (rc >= 0) {
                 old_cat = skp->smk_netlabel.attr.mls.cat;
                 rcu_assign_pointer(skp->smk_netlabel.attr.mls.cat, ncats.attr.mls.cat);
                 skp->smk_netlabel.attr.mls.lvl = ncats.attr.mls.lvl;
                 synchronize_rcu();
                 netlbl_catmap_free(old_cat);
                 rc = count;
                 /*
                  * This mapping may have been cached, so clear the cache.
                  */
                 netlbl_cache_invalidate();
         }
 
 out:
         mutex_unlock(&smack_cipso_lock);
         kfree(data);
         return rc;
 }
 
 /**
  * smk_write_cipso - write() for /smack/cipso
  * @file: 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)
 {
         return smk_set_cipso(file, buf, count, ppos, SMK_FIXED24_FMT);
 }
 
 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,
 };
 
 /*
  * Seq_file read operations for /smack/cipso2
  */
 
 /*
  * Print cipso labels in format:
  * label level[/cat[,cat]]
  */
 static int cipso2_seq_show(struct seq_file *s, void *v)
 {
         struct list_head  *list = v;
         struct smack_known *skp =
                 list_entry_rcu(list, struct smack_known, list);
         struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
         char sep = '/';
         int i;
 
         seq_printf(s, "%s %3d", skp->smk_known, skp->smk_netlabel.attr.mls.lvl);
 
         for (i = netlbl_catmap_walk(cmp, 0); i >= 0;
              i = netlbl_catmap_walk(cmp, i + 1)) {
                 seq_printf(s, "%c%d", sep, i);
                 sep = ',';
         }
 
         seq_putc(s, '\n');
 
         return 0;
 }
 
 static const struct seq_operations cipso2_seq_ops = {
         .start = cipso_seq_start,
         .next  = cipso_seq_next,
         .show  = cipso2_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * smk_open_cipso2 - open() for /smack/cipso2
  * @inode: inode structure representing file
  * @file: "cipso2" file pointer
  *
  * Connect our cipso_seq_* operations with /smack/cipso2
  * file_operations
  */
 static int smk_open_cipso2(struct inode *inode, struct file *file)
 {
         return seq_open(file, &cipso2_seq_ops);
 }
 
 /**
  * smk_write_cipso2 - write() for /smack/cipso2
  * @file: 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_cipso2(struct file *file, const char __user *buf,
                               size_t count, loff_t *ppos)
 {
         return smk_set_cipso(file, buf, count, ppos, SMK_LONG_FMT);
 }
 
 static const struct file_operations smk_cipso2_ops = {
         .open           = smk_open_cipso2,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_cipso2,
         .release        = seq_release,
 };
 
 /*
  * Seq_file read operations for /smack/netlabel
  */
 
 static void *net4addr_seq_start(struct seq_file *s, loff_t *pos)
 {
         return smk_seq_start(s, pos, &smk_net4addr_list);
 }
 
 static void *net4addr_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         return smk_seq_next(s, v, pos, &smk_net4addr_list);
 }
 
 /*
  * Print host/label pairs
  */
 static int net4addr_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smk_net4addr *skp =
                         list_entry_rcu(list, struct smk_net4addr, list);
         char *kp = SMACK_CIPSO_OPTION;
 
         if (skp->smk_label != NULL)
                 kp = skp->smk_label->smk_known;
         seq_printf(s, "%pI4/%d %s\n", &skp->smk_host.s_addr,
                         skp->smk_masks, kp);
 
         return 0;
 }
 
 static const struct seq_operations net4addr_seq_ops = {
         .start = net4addr_seq_start,
         .next  = net4addr_seq_next,
         .show  = net4addr_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * smk_open_net4addr - open() for /smack/netlabel
  * @inode: inode structure representing file
  * @file: "netlabel" file pointer
  *
  * Connect our net4addr_seq_* operations with /smack/netlabel
  * file_operations
  */
 static int smk_open_net4addr(struct inode *inode, struct file *file)
 {
         return seq_open(file, &net4addr_seq_ops);
 }
 
 /**
  * smk_net4addr_insert
  * @new : netlabel to insert
  *
  * This helper insert netlabel in the smack_net4addrs list
  * sorted by netmask length (longest to smallest)
  * locked by &smk_net4addr_lock in smk_write_net4addr
  *
  */
 static void smk_net4addr_insert(struct smk_net4addr *new)
 {
         struct smk_net4addr *m;
         struct smk_net4addr *m_next;
 
         if (list_empty(&smk_net4addr_list)) {
                 list_add_rcu(&new->list, &smk_net4addr_list);
                 return;
         }
 
         m = list_entry_rcu(smk_net4addr_list.next,
                            struct smk_net4addr, list);
 
         /* the comparison '>' is a bit hacky, but works */
         if (new->smk_masks > m->smk_masks) {
                 list_add_rcu(&new->list, &smk_net4addr_list);
                 return;
         }
 
         list_for_each_entry_rcu(m, &smk_net4addr_list, list) {
                 if (list_is_last(&m->list, &smk_net4addr_list)) {
                         list_add_rcu(&new->list, &m->list);
                         return;
                 }
                 m_next = list_entry_rcu(m->list.next,
                                         struct smk_net4addr, list);
                 if (new->smk_masks > m_next->smk_masks) {
                         list_add_rcu(&new->list, &m->list);
                         return;
                 }
         }
 }
 
 
 /**
  * smk_write_net4addr - write() for /smack/netlabel
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Accepts only one net4addr per write call.
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         struct smk_net4addr *snp;
         struct sockaddr_in newname;
         char *smack;
         struct smack_known *skp = NULL;
         char *data;
         char *host = (char *)&newname.sin_addr.s_addr;
         int rc;
         struct netlbl_audit audit_info;
         struct in_addr mask;
         unsigned int m;
         unsigned int masks;
         int found;
         u32 mask_bits = (1<<31);
         __be32 nsa;
         u32 temp_mask;
 
         /*
          * Must have privilege.
          * No partial writes.
          * Enough data must be present.
          * "<addr/mask, as a.b.c.d/e><space><label>"
          * "<addr, as a.b.c.d><space><label>"
          */
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
         if (*ppos != 0)
                 return -EINVAL;
         if (count < SMK_NETLBLADDRMIN || count > PAGE_SIZE - 1)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         smack = kzalloc(count + 1, GFP_KERNEL);
         if (smack == NULL) {
                 rc = -ENOMEM;
                 goto free_data_out;
         }
 
         rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%u %s",
                 &host[0], &host[1], &host[2], &host[3], &masks, smack);
         if (rc != 6) {
                 rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd %s",
                         &host[0], &host[1], &host[2], &host[3], smack);
                 if (rc != 5) {
                         rc = -EINVAL;
                         goto free_out;
                 }
                 masks = 32;
         }
         if (masks > BEBITS) {
                 rc = -EINVAL;
                 goto free_out;
         }
 
         /*
          * If smack begins with '-', it is an option, don't import it
          */
         if (smack[0] != '-') {
                 skp = smk_import_entry(smack, 0);
                 if (IS_ERR(skp)) {
                         rc = PTR_ERR(skp);
                         goto free_out;
                 }
         } else {
                 /*
                  * Only the -CIPSO option is supported for IPv4
                  */
                 if (strcmp(smack, SMACK_CIPSO_OPTION) != 0) {
                         rc = -EINVAL;
                         goto free_out;
                 }
         }
 
         for (m = masks, temp_mask = 0; m > 0; m--) {
                 temp_mask |= mask_bits;
                 mask_bits >>= 1;
         }
         mask.s_addr = cpu_to_be32(temp_mask);
 
         newname.sin_addr.s_addr &= mask.s_addr;
         /*
          * Only allow one writer at a time. Writes should be
          * quite rare and small in any case.
          */
         mutex_lock(&smk_net4addr_lock);
 
         nsa = newname.sin_addr.s_addr;
         /* try to find if the prefix is already in the list */
         found = 0;
         list_for_each_entry_rcu(snp, &smk_net4addr_list, list) {
                 if (snp->smk_host.s_addr == nsa && snp->smk_masks == masks) {
                         found = 1;
                         break;
                 }
         }
         smk_netlabel_audit_set(&audit_info);
 
         if (found == 0) {
                 snp = kzalloc(sizeof(*snp), GFP_KERNEL);
                 if (snp == NULL)
                         rc = -ENOMEM;
                 else {
                         rc = 0;
                         snp->smk_host.s_addr = newname.sin_addr.s_addr;
                         snp->smk_mask.s_addr = mask.s_addr;
                         snp->smk_label = skp;
                         snp->smk_masks = masks;
                         smk_net4addr_insert(snp);
                 }
         } else {
                 /*
                  * Delete the unlabeled entry, only if the previous label
                  * wasn't the special CIPSO option
                  */
                 if (snp->smk_label != NULL)
                         rc = netlbl_cfg_unlbl_static_del(&init_net, NULL,
                                         &snp->smk_host, &snp->smk_mask,
                                         PF_INET, &audit_info);
                 else
                         rc = 0;
                 snp->smk_label = skp;
         }
 
         /*
          * Now tell netlabel about the single label nature of
          * this host so that incoming packets get labeled.
          * but only if we didn't get the special CIPSO option
          */
         if (rc == 0 && skp != NULL)
                 rc = netlbl_cfg_unlbl_static_add(&init_net, NULL,
                         &snp->smk_host, &snp->smk_mask, PF_INET,
                         snp->smk_label->smk_secid, &audit_info);
 
         if (rc == 0)
                 rc = count;
 
         mutex_unlock(&smk_net4addr_lock);
 
 free_out:
         kfree(smack);
 free_data_out:
         kfree(data);
 
         return rc;
 }
 
 static const struct file_operations smk_net4addr_ops = {
         .open           = smk_open_net4addr,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_net4addr,
         .release        = seq_release,
 };
 
 #if IS_ENABLED(CONFIG_IPV6)
 /*
  * Seq_file read operations for /smack/netlabel6
  */
 
 static void *net6addr_seq_start(struct seq_file *s, loff_t *pos)
 {
         return smk_seq_start(s, pos, &smk_net6addr_list);
 }
 
 static void *net6addr_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         return smk_seq_next(s, v, pos, &smk_net6addr_list);
 }
 
 /*
  * Print host/label pairs
  */
 static int net6addr_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smk_net6addr *skp =
                          list_entry(list, struct smk_net6addr, list);
 
         if (skp->smk_label != NULL)
                 seq_printf(s, "%pI6/%d %s\n", &skp->smk_host, skp->smk_masks,
                                 skp->smk_label->smk_known);
 
         return 0;
 }
 
 static const struct seq_operations net6addr_seq_ops = {
         .start = net6addr_seq_start,
         .next  = net6addr_seq_next,
         .show  = net6addr_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * smk_open_net6addr - open() for /smack/netlabel
  * @inode: inode structure representing file
  * @file: "netlabel" file pointer
  *
  * Connect our net6addr_seq_* operations with /smack/netlabel
  * file_operations
  */
 static int smk_open_net6addr(struct inode *inode, struct file *file)
 {
         return seq_open(file, &net6addr_seq_ops);
 }
 
 /**
  * smk_net6addr_insert
  * @new : entry to insert
  *
  * This inserts an entry in the smack_net6addrs list
  * sorted by netmask length (longest to smallest)
  * locked by &smk_net6addr_lock in smk_write_net6addr
  *
  */
 static void smk_net6addr_insert(struct smk_net6addr *new)
 {
         struct smk_net6addr *m_next;
         struct smk_net6addr *m;
 
         if (list_empty(&smk_net6addr_list)) {
                 list_add_rcu(&new->list, &smk_net6addr_list);
                 return;
         }
 
         m = list_entry_rcu(smk_net6addr_list.next,
                            struct smk_net6addr, list);
 
         if (new->smk_masks > m->smk_masks) {
                 list_add_rcu(&new->list, &smk_net6addr_list);
                 return;
         }
 
         list_for_each_entry_rcu(m, &smk_net6addr_list, list) {
                 if (list_is_last(&m->list, &smk_net6addr_list)) {
                         list_add_rcu(&new->list, &m->list);
                         return;
                 }
                 m_next = list_entry_rcu(m->list.next,
                                         struct smk_net6addr, list);
                 if (new->smk_masks > m_next->smk_masks) {
                         list_add_rcu(&new->list, &m->list);
                         return;
                 }
         }
 }
 
 
 /**
  * smk_write_net6addr - write() for /smack/netlabel
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start
  *
  * Accepts only one net6addr per write call.
  * Returns number of bytes written or error code, as appropriate
  */
 static ssize_t smk_write_net6addr(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         struct smk_net6addr *snp;
         struct in6_addr newname;
         struct in6_addr fullmask;
         struct smack_known *skp = NULL;
         char *smack;
         char *data;
         int rc = 0;
         int found = 0;
         int i;
         unsigned int scanned[8];
         unsigned int m;
         unsigned int mask = 128;
 
         /*
          * Must have privilege.
          * No partial writes.
          * Enough data must be present.
          * "<addr/mask, as a:b:c:d:e:f:g:h/e><space><label>"
          * "<addr, as a:b:c:d:e:f:g:h><space><label>"
          */
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
         if (*ppos != 0)
                 return -EINVAL;
         if (count < SMK_NETLBLADDRMIN || count > PAGE_SIZE - 1)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         smack = kzalloc(count + 1, GFP_KERNEL);
         if (smack == NULL) {
                 rc = -ENOMEM;
                 goto free_data_out;
         }
 
         i = sscanf(data, "%x:%x:%x:%x:%x:%x:%x:%x/%u %s",
                         &scanned[0], &scanned[1], &scanned[2], &scanned[3],
                         &scanned[4], &scanned[5], &scanned[6], &scanned[7],
                         &mask, smack);
         if (i != 10) {
                 i = sscanf(data, "%x:%x:%x:%x:%x:%x:%x:%x %s",
                                 &scanned[0], &scanned[1], &scanned[2],
                                 &scanned[3], &scanned[4], &scanned[5],
                                 &scanned[6], &scanned[7], smack);
                 if (i != 9) {
                         rc = -EINVAL;
                         goto free_out;
                 }
         }
         if (mask > 128) {
                 rc = -EINVAL;
                 goto free_out;
         }
         for (i = 0; i < 8; i++) {
                 if (scanned[i] > 0xffff) {
                         rc = -EINVAL;
                         goto free_out;
                 }
                 newname.s6_addr16[i] = htons(scanned[i]);
         }
 
         /*
          * If smack begins with '-', it is an option, don't import it
          */
         if (smack[0] != '-') {
                 skp = smk_import_entry(smack, 0);
                 if (IS_ERR(skp)) {
                         rc = PTR_ERR(skp);
                         goto free_out;
                 }
         } else {
                 /*
                  * Only -DELETE is supported for IPv6
                  */
                 if (strcmp(smack, SMACK_DELETE_OPTION) != 0) {
                         rc = -EINVAL;
                         goto free_out;
                 }
         }
 
         for (i = 0, m = mask; i < 8; i++) {
                 if (m >= 16) {
                         fullmask.s6_addr16[i] = 0xffff;
                         m -= 16;
                 } else if (m > 0) {
                         fullmask.s6_addr16[i] = (1 << m) - 1;
                         m = 0;
                 } else
                         fullmask.s6_addr16[i] = 0;
                 newname.s6_addr16[i] &= fullmask.s6_addr16[i];
         }
 
         /*
          * Only allow one writer at a time. Writes should be
          * quite rare and small in any case.
          */
         mutex_lock(&smk_net6addr_lock);
         /*
          * Try to find the prefix in the list
          */
         list_for_each_entry_rcu(snp, &smk_net6addr_list, list) {
                 if (mask != snp->smk_masks)
                         continue;
                 for (found = 1, i = 0; i < 8; i++) {
                         if (newname.s6_addr16[i] !=
                             snp->smk_host.s6_addr16[i]) {
                                 found = 0;
                                 break;
                         }
                 }
                 if (found == 1)
                         break;
         }
         if (found == 0) {
                 snp = kzalloc(sizeof(*snp), GFP_KERNEL);
                 if (snp == NULL)
                         rc = -ENOMEM;
                 else {
                         snp->smk_host = newname;
                         snp->smk_mask = fullmask;
                         snp->smk_masks = mask;
                         snp->smk_label = skp;
                         smk_net6addr_insert(snp);
                 }
         } else {
                 snp->smk_label = skp;
         }
 
         if (rc == 0)
                 rc = count;
 
         mutex_unlock(&smk_net6addr_lock);
 
 free_out:
         kfree(smack);
 free_data_out:
         kfree(data);
 
         return rc;
 }
 
 static const struct file_operations smk_net6addr_ops = {
         .open           = smk_open_net6addr,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_net6addr,
         .release        = seq_release,
 };
 #endif /* CONFIG_IPV6 */
 
 /**
  * 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
  * @file: 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 (!smack_privileged(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,
         .llseek         = default_llseek,
 };
 
 /**
  * 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
  * @file: 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)
 {
         struct smack_known *skp;
         char temp[80];
         int i;
 
         if (!smack_privileged(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;
 
         /*
          * Don't do anything if the value hasn't actually changed.
          * If it is changing reset the level on entries that were
          * set up to be direct when they were created.
          */
         if (smack_cipso_direct != i) {
                 mutex_lock(&smack_known_lock);
                 list_for_each_entry_rcu(skp, &smack_known_list, list)
                         if (skp->smk_netlabel.attr.mls.lvl ==
                             smack_cipso_direct)
                                 skp->smk_netlabel.attr.mls.lvl = i;
                 smack_cipso_direct = i;
                 mutex_unlock(&smack_known_lock);
         }
 
         return count;
 }
 
 static const struct file_operations smk_direct_ops = {
         .read           = smk_read_direct,
         .write          = smk_write_direct,
         .llseek         = default_llseek,
 };
 
 /**
  * smk_read_mapped - read() for /smack/mapped
  * @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_mapped(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_mapped);
         rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
 
         return rc;
 }
 
 /**
  * smk_write_mapped - write() for /smack/mapped
  * @file: 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_mapped(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         struct smack_known *skp;
         char temp[80];
         int i;
 
         if (!smack_privileged(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;
 
         /*
          * Don't do anything if the value hasn't actually changed.
          * If it is changing reset the level on entries that were
          * set up to be mapped when they were created.
          */
         if (smack_cipso_mapped != i) {
                 mutex_lock(&smack_known_lock);
                 list_for_each_entry_rcu(skp, &smack_known_list, list)
                         if (skp->smk_netlabel.attr.mls.lvl ==
                             smack_cipso_mapped)
                                 skp->smk_netlabel.attr.mls.lvl = i;
                 smack_cipso_mapped = i;
                 mutex_unlock(&smack_known_lock);
         }
 
         return count;
 }
 
 static const struct file_operations smk_mapped_ops = {
         .read           = smk_read_mapped,
         .write          = smk_write_mapped,
         .llseek         = default_llseek,
 };
 
 /**
  * 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->smk_known) + 1;
 
         if (cn >= asize)
                 rc = simple_read_from_buffer(buf, cn, ppos,
                                              smack_net_ambient->smk_known,
                                              asize);
         else
                 rc = -EINVAL;
 
         mutex_unlock(&smack_ambient_lock);
 
         return rc;
 }
 
 /**
  * smk_write_ambient - write() for /smack/ambient
  * @file: 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)
 {
         struct smack_known *skp;
         char *oldambient;
         char *data;
         int rc = count;
 
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         /* Enough data must be present */
         if (count == 0 || count > PAGE_SIZE)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         skp = smk_import_entry(data, count);
         if (IS_ERR(skp)) {
                 rc = PTR_ERR(skp);
                 goto out;
         }
 
         mutex_lock(&smack_ambient_lock);
 
         oldambient = smack_net_ambient->smk_known;
         smack_net_ambient = skp;
         smk_unlbl_ambient(oldambient);
 
         mutex_unlock(&smack_ambient_lock);
 
 out:
         kfree(data);
         return rc;
 }
 
 static const struct file_operations smk_ambient_ops = {
         .read           = smk_read_ambient,
         .write          = smk_write_ambient,
         .llseek         = default_llseek,
 };
 
 /*
  * Seq_file operations for /smack/onlycap
  */
 static void *onlycap_seq_start(struct seq_file *s, loff_t *pos)
 {
         return smk_seq_start(s, pos, &smack_onlycap_list);
 }
 
 static void *onlycap_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         return smk_seq_next(s, v, pos, &smack_onlycap_list);
 }
 
 static int onlycap_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smack_known_list_elem *sklep =
                 list_entry_rcu(list, struct smack_known_list_elem, list);
 
         seq_puts(s, sklep->smk_label->smk_known);
         seq_putc(s, ' ');
 
         return 0;
 }
 
 static const struct seq_operations onlycap_seq_ops = {
         .start = onlycap_seq_start,
         .next  = onlycap_seq_next,
         .show  = onlycap_seq_show,
         .stop  = smk_seq_stop,
 };
 
 static int smk_open_onlycap(struct inode *inode, struct file *file)
 {
         return seq_open(file, &onlycap_seq_ops);
 }
 
 /**
  * smk_list_swap_rcu - swap public list with a private one in RCU-safe way
  * The caller must hold appropriate mutex to prevent concurrent modifications
  * to the public list.
  * Private list is assumed to be not accessible to other threads yet.
  *
  * @public: public list
  * @private: private list
  */
 static void smk_list_swap_rcu(struct list_head *public,
                               struct list_head *private)
 {
         struct list_head *first, *last;
 
         if (list_empty(public)) {
                 list_splice_init_rcu(private, public, synchronize_rcu);
         } else {
                 /* Remember public list before replacing it */
                 first = public->next;
                 last = public->prev;
 
                 /* Publish private list in place of public in RCU-safe way */
                 private->prev->next = public;
                 private->next->prev = public;
                 rcu_assign_pointer(public->next, private->next);
                 public->prev = private->prev;
 
                 synchronize_rcu();
 
                 /* When all readers are done with the old public list,
                  * attach it in place of private */
                 private->next = first;
                 private->prev = last;
                 first->prev = private;
                 last->next = private;
         }
 }
 
 /**
  * smk_parse_label_list - parse list of Smack labels, separated by spaces
  *
  * @data: the string to parse
  * @list: destination list
  *
  * Returns zero on success or error code, as appropriate
  */
 static int smk_parse_label_list(char *data, struct list_head *list)
 {
         char *tok;
         struct smack_known *skp;
         struct smack_known_list_elem *sklep;
 
         while ((tok = strsep(&data, " ")) != NULL) {
                 if (!*tok)
                         continue;
 
                 skp = smk_import_entry(tok, 0);
                 if (IS_ERR(skp))
                         return PTR_ERR(skp);
 
                 sklep = kzalloc(sizeof(*sklep), GFP_KERNEL);
                 if (sklep == NULL)
                         return -ENOMEM;
 
                 sklep->smk_label = skp;
                 list_add(&sklep->list, list);
         }
 
         return 0;
 }
 
 /**
  * smk_destroy_label_list - destroy a list of smack_known_list_elem
  * @list: header pointer of the list to destroy
  */
 void smk_destroy_label_list(struct list_head *list)
 {
         struct smack_known_list_elem *sklep;
         struct smack_known_list_elem *sklep2;
 
         list_for_each_entry_safe(sklep, sklep2, list, list)
                 kfree(sklep);
 
         INIT_LIST_HEAD(list);
 }
 
 /**
  * smk_write_onlycap - write() for smackfs/onlycap
  * @file: 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 *data;
         LIST_HEAD(list_tmp);
         int rc;
 
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count > PAGE_SIZE)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         rc = smk_parse_label_list(data, &list_tmp);
         kfree(data);
 
         /*
          * Clear the smack_onlycap on invalid label errors. This means
          * that we can pass a null string to unset the onlycap value.
          *
          * Importing will also reject a label beginning with '-',
          * so "-usecapabilities" will also work.
          *
          * But do so only on invalid label, not on system errors.
          * The invalid label must be first to count as clearing attempt.
          */
         if (!rc || (rc == -EINVAL && list_empty(&list_tmp))) {
                 mutex_lock(&smack_onlycap_lock);
                 smk_list_swap_rcu(&smack_onlycap_list, &list_tmp);
                 mutex_unlock(&smack_onlycap_lock);
                 rc = count;
         }
 
         smk_destroy_label_list(&list_tmp);
 
         return rc;
 }
 
 static const struct file_operations smk_onlycap_ops = {
         .open           = smk_open_onlycap,
         .read           = seq_read,
         .write          = smk_write_onlycap,
         .llseek         = seq_lseek,
         .release        = seq_release,
 };
 
 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 /**
  * smk_read_unconfined - read() for smackfs/unconfined
  * @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_unconfined(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_unconfined != NULL)
                 smack = smack_unconfined->smk_known;
 
         asize = strlen(smack) + 1;
 
         if (cn >= asize)
                 rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);
 
         return rc;
 }
 
 /**
  * smk_write_unconfined - write() for smackfs/unconfined
  * @file: 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_unconfined(struct file *file, const char __user *buf,
                                         size_t count, loff_t *ppos)
 {
         char *data;
         struct smack_known *skp;
         int rc = count;
 
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count > PAGE_SIZE)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         /*
          * Clear the smack_unconfined on invalid label errors. This means
          * that we can pass a null string to unset the unconfined value.
          *
          * Importing will also reject a label beginning with '-',
          * so "-confine" will also work.
          *
          * But do so only on invalid label, not on system errors.
          */
         skp = smk_import_entry(data, count);
         if (PTR_ERR(skp) == -EINVAL)
                 skp = NULL;
         else if (IS_ERR(skp)) {
                 rc = PTR_ERR(skp);
                 goto freeout;
         }
 
         smack_unconfined = skp;
 
 freeout:
         kfree(data);
         return rc;
 }
 
 static const struct file_operations smk_unconfined_ops = {
         .read           = smk_read_unconfined,
         .write          = smk_write_unconfined,
         .llseek         = default_llseek,
 };
 #endif /* CONFIG_SECURITY_SMACK_BRINGUP */
 
 /**
  * smk_read_logging - read() for /smack/logging
  * @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_logging(struct file *filp, char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char temp[32];
         ssize_t rc;
 
         if (*ppos != 0)
                 return 0;
 
         sprintf(temp, "%d\n", log_policy);
         rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
         return rc;
 }
 
 /**
  * smk_write_logging - write() for /smack/logging
  * @file: 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_logging(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char temp[32];
         int i;
 
         if (!smack_privileged(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;
         if (i < 0 || i > 3)
                 return -EINVAL;
         log_policy = i;
         return count;
 }
 
 
 
 static const struct file_operations smk_logging_ops = {
         .read           = smk_read_logging,
         .write          = smk_write_logging,
         .llseek         = default_llseek,
 };
 
 /*
  * Seq_file read operations for /smack/load-self
  */
 
 static void *load_self_seq_start(struct seq_file *s, loff_t *pos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_seq_start(s, pos, &tsp->smk_rules);
 }
 
 static void *load_self_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_seq_next(s, v, pos, &tsp->smk_rules);
 }
 
 static int load_self_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smack_rule *srp =
                 list_entry_rcu(list, struct smack_rule, list);
 
         smk_rule_show(s, srp, SMK_LABELLEN);
 
         return 0;
 }
 
 static const struct seq_operations load_self_seq_ops = {
         .start = load_self_seq_start,
         .next  = load_self_seq_next,
         .show  = load_self_seq_show,
         .stop  = smk_seq_stop,
 };
 
 
 /**
  * smk_open_load_self - open() for /smack/load-self2
  * @inode: inode structure representing file
  * @file: "load" file pointer
  *
  * For reading, use load_seq_* seq_file reading operations.
  */
 static int smk_open_load_self(struct inode *inode, struct file *file)
 {
         return seq_open(file, &load_self_seq_ops);
 }
 
 /**
  * smk_write_load_self - write() for /smack/load-self
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  *
  */
 static ssize_t smk_write_load_self(struct file *file, const char __user *buf,
                               size_t count, loff_t *ppos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_write_rules_list(file, buf, count, ppos, &tsp->smk_rules,
                                     &tsp->smk_rules_lock, SMK_FIXED24_FMT);
 }
 
 static const struct file_operations smk_load_self_ops = {
         .open           = smk_open_load_self,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_load_self,
         .release        = seq_release,
 };
 
 /**
  * smk_user_access - handle access check transaction
  * @file: file pointer
  * @buf: data from user space
  * @count: bytes sent
  * @ppos: where to start - must be 0
  * @format: /smack/load or /smack/load2 or /smack/change-rule format.
  */
 static ssize_t smk_user_access(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos, int format)
 {
         struct smack_parsed_rule rule;
         char *data;
         int res;
 
         data = simple_transaction_get(file, buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         if (format == SMK_FIXED24_FMT) {
                 if (count < SMK_LOADLEN)
                         return -EINVAL;
                 res = smk_parse_rule(data, &rule, 0);
         } else {
                 /*
                  * simple_transaction_get() returns null-terminated data
                  */
                 res = smk_parse_long_rule(data, &rule, 0, 3);
         }
 
         if (res >= 0)
                 res = smk_access(rule.smk_subject, rule.smk_object,
                                  rule.smk_access1, NULL);
         else if (res != -ENOENT)
                 return res;
 
         /*
          * smk_access() can return a value > 0 in the "bringup" case.
          */
         data[0] = res >= 0 ? '1' : '';
         data[1] = '\0';
 
         simple_transaction_set(file, 2);
 
         if (format == SMK_FIXED24_FMT)
                 return SMK_LOADLEN;
         return count;
 }
 
 /**
  * smk_write_access - handle access check transaction
  * @file: file pointer
  * @buf: data from user space
  * @count: bytes sent
  * @ppos: where to start - must be 0
  */
 static ssize_t smk_write_access(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         return smk_user_access(file, buf, count, ppos, SMK_FIXED24_FMT);
 }
 
 static const struct file_operations smk_access_ops = {
         .write          = smk_write_access,
         .read           = simple_transaction_read,
         .release        = simple_transaction_release,
         .llseek         = generic_file_llseek,
 };
 
 
 /*
  * Seq_file read operations for /smack/load2
  */
 
 static int load2_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smack_rule *srp;
         struct smack_known *skp =
                 list_entry_rcu(list, struct smack_known, list);
 
         list_for_each_entry_rcu(srp, &skp->smk_rules, list)
                 smk_rule_show(s, srp, SMK_LONGLABEL);
 
         return 0;
 }
 
 static const struct seq_operations load2_seq_ops = {
         .start = load2_seq_start,
         .next  = load2_seq_next,
         .show  = load2_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * smk_open_load2 - open() for /smack/load2
  * @inode: inode structure representing file
  * @file: "load2" file pointer
  *
  * For reading, use load2_seq_* seq_file reading operations.
  */
 static int smk_open_load2(struct inode *inode, struct file *file)
 {
         return seq_open(file, &load2_seq_ops);
 }
 
 /**
  * smk_write_load2 - write() for /smack/load2
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  *
  */
 static ssize_t smk_write_load2(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         /*
          * Must have privilege.
          */
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         return smk_write_rules_list(file, buf, count, ppos, NULL, NULL,
                                     SMK_LONG_FMT);
 }
 
 static const struct file_operations smk_load2_ops = {
         .open           = smk_open_load2,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_load2,
         .release        = seq_release,
 };
 
 /*
  * Seq_file read operations for /smack/load-self2
  */
 
 static void *load_self2_seq_start(struct seq_file *s, loff_t *pos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_seq_start(s, pos, &tsp->smk_rules);
 }
 
 static void *load_self2_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_seq_next(s, v, pos, &tsp->smk_rules);
 }
 
 static int load_self2_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smack_rule *srp =
                 list_entry_rcu(list, struct smack_rule, list);
 
         smk_rule_show(s, srp, SMK_LONGLABEL);
 
         return 0;
 }
 
 static const struct seq_operations load_self2_seq_ops = {
         .start = load_self2_seq_start,
         .next  = load_self2_seq_next,
         .show  = load_self2_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * smk_open_load_self2 - open() for /smack/load-self2
  * @inode: inode structure representing file
  * @file: "load" file pointer
  *
  * For reading, use load_seq_* seq_file reading operations.
  */
 static int smk_open_load_self2(struct inode *inode, struct file *file)
 {
         return seq_open(file, &load_self2_seq_ops);
 }
 
 /**
  * smk_write_load_self2 - write() for /smack/load-self2
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  *
  */
 static ssize_t smk_write_load_self2(struct file *file, const char __user *buf,
                               size_t count, loff_t *ppos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_write_rules_list(file, buf, count, ppos, &tsp->smk_rules,
                                     &tsp->smk_rules_lock, SMK_LONG_FMT);
 }
 
 static const struct file_operations smk_load_self2_ops = {
         .open           = smk_open_load_self2,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_load_self2,
         .release        = seq_release,
 };
 
 /**
  * smk_write_access2 - handle access check transaction
  * @file: file pointer
  * @buf: data from user space
  * @count: bytes sent
  * @ppos: where to start - must be 0
  */
 static ssize_t smk_write_access2(struct file *file, const char __user *buf,
                                         size_t count, loff_t *ppos)
 {
         return smk_user_access(file, buf, count, ppos, SMK_LONG_FMT);
 }
 
 static const struct file_operations smk_access2_ops = {
         .write          = smk_write_access2,
         .read           = simple_transaction_read,
         .release        = simple_transaction_release,
         .llseek         = generic_file_llseek,
 };
 
 /**
  * smk_write_revoke_subj - write() for /smack/revoke-subject
  * @file: file pointer
  * @buf: data from user space
  * @count: bytes sent
  * @ppos: where to start - must be 0
  */
 static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char *data;
         const char *cp;
         struct smack_known *skp;
         struct smack_rule *sp;
         struct list_head *rule_list;
         struct mutex *rule_lock;
         int rc = count;
 
         if (*ppos != 0)
                 return -EINVAL;
 
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (count == 0 || count > SMK_LONGLABEL)
                 return -EINVAL;
 
         data = memdup_user(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         cp = smk_parse_smack(data, count);
         if (IS_ERR(cp)) {
                 rc = PTR_ERR(cp);
                 goto out_data;
         }
 
         skp = smk_find_entry(cp);
         if (skp == NULL)
                 goto out_cp;
 
         rule_list = &skp->smk_rules;
         rule_lock = &skp->smk_rules_lock;
 
         mutex_lock(rule_lock);
 
         list_for_each_entry_rcu(sp, rule_list, list)
                 sp->smk_access = 0;
 
         mutex_unlock(rule_lock);
 
 out_cp:
         kfree(cp);
 out_data:
         kfree(data);
 
         return rc;
 }
 
 static const struct file_operations smk_revoke_subj_ops = {
         .write          = smk_write_revoke_subj,
         .read           = simple_transaction_read,
         .release        = simple_transaction_release,
         .llseek         = generic_file_llseek,
 };
 
 /**
  * smk_init_sysfs - initialize /sys/fs/smackfs
  *
  */
 static int smk_init_sysfs(void)
 {
         return sysfs_create_mount_point(fs_kobj, "smackfs");
 }
 
 /**
  * smk_write_change_rule - write() for /smack/change-rule
  * @file: file pointer
  * @buf: data from user space
  * @count: bytes sent
  * @ppos: where to start - must be 0
  */
 static ssize_t smk_write_change_rule(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         /*
          * Must have privilege.
          */
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         return smk_write_rules_list(file, buf, count, ppos, NULL, NULL,
                                     SMK_CHANGE_FMT);
 }
 
 static const struct file_operations smk_change_rule_ops = {
         .write          = smk_write_change_rule,
         .read           = simple_transaction_read,
         .release        = simple_transaction_release,
         .llseek         = generic_file_llseek,
 };
 
 /**
  * smk_read_syslog - read() for smackfs/syslog
  * @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_syslog(struct file *filp, char __user *buf,
                                 size_t cn, loff_t *ppos)
 {
         struct smack_known *skp;
         ssize_t rc = -EINVAL;
         int asize;
 
         if (*ppos != 0)
                 return 0;
 
         if (smack_syslog_label == NULL)
                 skp = &smack_known_star;
         else
                 skp = smack_syslog_label;
 
         asize = strlen(skp->smk_known) + 1;
 
         if (cn >= asize)
                 rc = simple_read_from_buffer(buf, cn, ppos, skp->smk_known,
                                                 asize);
 
         return rc;
 }
 
 /**
  * smk_write_syslog - write() for smackfs/syslog
  * @file: 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_syslog(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char *data;
         struct smack_known *skp;
         int rc = count;
 
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         /* Enough data must be present */
         if (count == 0 || count > PAGE_SIZE)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         skp = smk_import_entry(data, count);
         if (IS_ERR(skp))
                 rc = PTR_ERR(skp);
         else
                 smack_syslog_label = skp;
 
         kfree(data);
         return rc;
 }
 
 static const struct file_operations smk_syslog_ops = {
         .read           = smk_read_syslog,
         .write          = smk_write_syslog,
         .llseek         = default_llseek,
 };
 
 /*
  * Seq_file read operations for /smack/relabel-self
  */
 
 static void *relabel_self_seq_start(struct seq_file *s, loff_t *pos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_seq_start(s, pos, &tsp->smk_relabel);
 }
 
 static void *relabel_self_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
         struct task_smack *tsp = smack_cred(current_cred());
 
         return smk_seq_next(s, v, pos, &tsp->smk_relabel);
 }
 
 static int relabel_self_seq_show(struct seq_file *s, void *v)
 {
         struct list_head *list = v;
         struct smack_known_list_elem *sklep =
                 list_entry(list, struct smack_known_list_elem, list);
 
         seq_puts(s, sklep->smk_label->smk_known);
         seq_putc(s, ' ');
 
         return 0;
 }
 
 static const struct seq_operations relabel_self_seq_ops = {
         .start = relabel_self_seq_start,
         .next  = relabel_self_seq_next,
         .show  = relabel_self_seq_show,
         .stop  = smk_seq_stop,
 };
 
 /**
  * smk_open_relabel_self - open() for /smack/relabel-self
  * @inode: inode structure representing file
  * @file: "relabel-self" file pointer
  *
  * Connect our relabel_self_seq_* operations with /smack/relabel-self
  * file_operations
  */
 static int smk_open_relabel_self(struct inode *inode, struct file *file)
 {
         return seq_open(file, &relabel_self_seq_ops);
 }
 
 /**
  * smk_write_relabel_self - write() for /smack/relabel-self
  * @file: file pointer, not actually used
  * @buf: where to get the data from
  * @count: bytes sent
  * @ppos: where to start - must be 0
  *
  */
 static ssize_t smk_write_relabel_self(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char *data;
         int rc;
         LIST_HEAD(list_tmp);
 
         /*
          * Must have privilege.
          */
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         /*
          * No partial write.
          * Enough data must be present.
          */
         if (*ppos != 0)
                 return -EINVAL;
         if (count == 0 || count > PAGE_SIZE)
                 return -EINVAL;
 
         data = memdup_user_nul(buf, count);
         if (IS_ERR(data))
                 return PTR_ERR(data);
 
         rc = smk_parse_label_list(data, &list_tmp);
         kfree(data);
 
         if (!rc || (rc == -EINVAL && list_empty(&list_tmp))) {
                 struct cred *new;
                 struct task_smack *tsp;
 
                 new = prepare_creds();
                 if (!new) {
                         rc = -ENOMEM;
                         goto out;
                 }
                 tsp = smack_cred(new);
                 smk_destroy_label_list(&tsp->smk_relabel);
                 list_splice(&list_tmp, &tsp->smk_relabel);
                 commit_creds(new);
                 return count;
         }
 out:
         smk_destroy_label_list(&list_tmp);
         return rc;
 }
 
 static const struct file_operations smk_relabel_self_ops = {
         .open           = smk_open_relabel_self,
         .read           = seq_read,
         .llseek         = seq_lseek,
         .write          = smk_write_relabel_self,
         .release        = seq_release,
 };
 
 /**
  * smk_read_ptrace - read() for /smack/ptrace
  * @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_ptrace(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
 {
         char temp[32];
         ssize_t rc;
 
         if (*ppos != 0)
                 return 0;
 
         sprintf(temp, "%d\n", smack_ptrace_rule);
         rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
         return rc;
 }
 
 /**
  * smk_write_ptrace - write() for /smack/ptrace
  * @file: file pointer
  * @buf: data from user space
  * @count: bytes sent
  * @ppos: where to start - must be 0
  */
 static ssize_t smk_write_ptrace(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)
 {
         char temp[32];
         int i;
 
         if (!smack_privileged(CAP_MAC_ADMIN))
                 return -EPERM;
 
         if (*ppos != 0 || 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;
         if (i < SMACK_PTRACE_DEFAULT || i > SMACK_PTRACE_MAX)
                 return -EINVAL;
         smack_ptrace_rule = i;
 
         return count;
 }
 
 static const struct file_operations smk_ptrace_ops = {
         .write          = smk_write_ptrace,
         .read           = smk_read_ptrace,
         .llseek         = default_llseek,
 };
 
 /**
  * smk_fill_super - fill the smackfs superblock
  * @sb: the empty superblock
  * @fc: unused
  *
  * Fill in the well known entries for the smack filesystem
  *
  * Returns 0 on success, an error code on failure
  */
 static int smk_fill_super(struct super_block *sb, struct fs_context *fc)
 {
         int rc;
 
         static const 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_NET4ADDR] = {
                         "netlabel", &smk_net4addr_ops, S_IRUGO|S_IWUSR},
                 [SMK_ONLYCAP] = {
                         "onlycap", &smk_onlycap_ops, S_IRUGO|S_IWUSR},
                 [SMK_LOGGING] = {
                         "logging", &smk_logging_ops, S_IRUGO|S_IWUSR},
                 [SMK_LOAD_SELF] = {
                         "load-self", &smk_load_self_ops, S_IRUGO|S_IWUGO},
                 [SMK_ACCESSES] = {
                         "access", &smk_access_ops, S_IRUGO|S_IWUGO},
                 [SMK_MAPPED] = {
                         "mapped", &smk_mapped_ops, S_IRUGO|S_IWUSR},
                 [SMK_LOAD2] = {
                         "load2", &smk_load2_ops, S_IRUGO|S_IWUSR},
                 [SMK_LOAD_SELF2] = {
                         "load-self2", &smk_load_self2_ops, S_IRUGO|S_IWUGO},
                 [SMK_ACCESS2] = {
                         "access2", &smk_access2_ops, S_IRUGO|S_IWUGO},
                 [SMK_CIPSO2] = {
                         "cipso2", &smk_cipso2_ops, S_IRUGO|S_IWUSR},
                 [SMK_REVOKE_SUBJ] = {
                         "revoke-subject", &smk_revoke_subj_ops,
                         S_IRUGO|S_IWUSR},
                 [SMK_CHANGE_RULE] = {
                         "change-rule", &smk_change_rule_ops, S_IRUGO|S_IWUSR},
                 [SMK_SYSLOG] = {
                         "syslog", &smk_syslog_ops, S_IRUGO|S_IWUSR},
                 [SMK_PTRACE] = {
                         "ptrace", &smk_ptrace_ops, S_IRUGO|S_IWUSR},
 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
                 [SMK_UNCONFINED] = {
                         "unconfined", &smk_unconfined_ops, S_IRUGO|S_IWUSR},
 #endif
 #if IS_ENABLED(CONFIG_IPV6)
                 [SMK_NET6ADDR] = {
                         "ipv6host", &smk_net6addr_ops, S_IRUGO|S_IWUSR},
 #endif /* CONFIG_IPV6 */
                 [SMK_RELABEL_SELF] = {
                         "relabel-self", &smk_relabel_self_ops,
                                 S_IRUGO|S_IWUGO},
                 /* 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;
         }
 
         return 0;
 }
 
 /**
  * smk_get_tree - get the smackfs superblock
  * @fc: The mount context, including any options
  *
  * Just passes everything along.
  *
  * Returns what the lower level code does.
  */
 static int smk_get_tree(struct fs_context *fc)
 {
         return get_tree_single(fc, smk_fill_super);
 }
 
 static const struct fs_context_operations smk_context_ops = {
         .get_tree       = smk_get_tree,
 };
 
 /**
  * smk_init_fs_context - Initialise a filesystem context for smackfs
  * @fc: The blank mount context
  */
 static int smk_init_fs_context(struct fs_context *fc)
 {
         fc->ops = &smk_context_ops;
         return 0;
 }
 
 static struct file_system_type smk_fs_type = {
         .name           = "smackfs",
         .init_fs_context = smk_init_fs_context,
         .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;
         int rc;
 
         if (smack_enabled == 0)
                 return 0;
 
         err = smk_init_sysfs();
         if (err)
                 printk(KERN_ERR "smackfs: sysfs mountpoint problem.\n");
 
         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);
 
         rc = smack_populate_secattr(&smack_known_floor);
         if (err == 0 && rc < 0)
                 err = rc;
         rc = smack_populate_secattr(&smack_known_hat);
         if (err == 0 && rc < 0)
                 err = rc;
         rc = smack_populate_secattr(&smack_known_huh);
         if (err == 0 && rc < 0)
                 err = rc;
         rc = smack_populate_secattr(&smack_known_star);
         if (err == 0 && rc < 0)
                 err = rc;
         rc = smack_populate_secattr(&smack_known_web);
         if (err == 0 && rc < 0)
                 err = rc;
 
         return err;
 }
 
 __initcall(init_smk_fs);
 

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