security/apparmor/procattr.c

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor /proc/<pid>/attr/ interface functions
   5  *
   6  * Copyright (C) 1998-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #include "include/apparmor.h"
  16 #include "include/cred.h"
  17 #include "include/policy.h"
  18 #include "include/policy_ns.h"
  19 #include "include/domain.h"
  20 #include "include/procattr.h"
  21
  22
  23 /**
  24  * aa_getprocattr - Return the profile information for @profile
  25  * @profile: the profile to print profile info about  (NOT NULL)
  26  * @string: Returns - string containing the profile info (NOT NULL)
  27  *
  28  * Returns: length of @string on success else error on failure
  29  *
  30  * Requires: profile != NULL
  31  *
  32  * Creates a string containing the namespace_name://profile_name for
  33  * @profile.
  34  *
  35  * Returns: size of string placed in @string else error code on failure
  36  */
  37 int aa_getprocattr(struct aa_label *label, char **string)
  38 {
  39         struct aa_ns *ns = labels_ns(label);
  40         struct aa_ns *current_ns = aa_get_current_ns();
  41         int len;
  42
  43         if (!aa_ns_visible(current_ns, ns, true)) {
  44                 aa_put_ns(current_ns);
  45                 return -EACCES;
  46         }
  47
  48         len = aa_label_snxprint(NULL, 0, current_ns, label,
  49                                 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
  50                                 FLAG_HIDDEN_UNCONFINED);
  51         AA_BUG(len < 0);
  52
  53         *string = kmalloc(len + 2, GFP_KERNEL);
  54         if (!*string) {
  55                 aa_put_ns(current_ns);
  56                 return -ENOMEM;
  57         }
  58
  59         len = aa_label_snxprint(*string, len + 2, current_ns, label,
  60                                 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
  61                                 FLAG_HIDDEN_UNCONFINED);
  62         if (len < 0) {
  63                 aa_put_ns(current_ns);
  64                 return len;
  65         }
  66
  67         (*string)[len] = '\n';
  68         (*string)[len + 1] = 0;
  69
  70         aa_put_ns(current_ns);
  71         return len + 1;
  72 }
  73
  74 /**
  75  * split_token_from_name - separate a string of form  <token>^<name>
  76  * @op: operation being checked
  77  * @args: string to parse  (NOT NULL)
  78  * @token: stores returned parsed token value  (NOT NULL)
  79  *
  80  * Returns: start position of name after token else NULL on failure
  81  */
  82 static char *split_token_from_name(const char *op, char *args, u64 *token)
  83 {
  84         char *name;
  85
  86         *token = simple_strtoull(args, &name, 16);
  87         if ((name == args) || *name != '^') {
  88                 AA_ERROR("%s: Invalid input '%s'", op, args);
  89                 return ERR_PTR(-EINVAL);
  90         }
  91
  92         name++;                 /* skip ^ */
  93         if (!*name)
  94                 name = NULL;
  95         return name;
  96 }
  97
  98 /**
  99  * aa_setprocattr_chagnehat - handle procattr interface to change_hat
 100  * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
 101  * @size: size of the args
 102  * @flags: set of flags governing behavior
 103  *
 104  * Returns: %0 or error code if change_hat fails
 105  */
 106 int aa_setprocattr_changehat(char *args, size_t size, int flags)
 107 {
 108         char *hat;
 109         u64 token;
 110         const char *hats[16];           /* current hard limit on # of names */
 111         int count = 0;
 112
 113         hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
 114         if (IS_ERR(hat))
 115                 return PTR_ERR(hat);
 116
 117         if (!hat && !token) {
 118                 AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
 119                 return -EINVAL;
 120         }
 121
 122         if (hat) {
 123                 /* set up hat name vector, args guaranteed null terminated
 124                  * at args[size] by setprocattr.
 125                  *
 126                  * If there are multiple hat names in the buffer each is
 127                  * separated by a \0.  Ie. userspace writes them pre tokenized
 128                  */
 129                 char *end = args + size;
 130                 for (count = 0; (hat < end) && count < 16; ++count) {
 131                         char *next = hat + strlen(hat) + 1;
 132                         hats[count] = hat;
 133                         AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
 134                                  , __func__, current->pid, token, count, hat);
 135                         hat = next;
 136                 }
 137         } else
 138                 AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
 139                          __func__, current->pid, token, count, "<NULL>");
 140
 141         return aa_change_hat(hats, count, token, flags);
 142 }