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/context.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_profile *profile, char **string)
  38 {
  39         char *str;
  40         int len = 0, mode_len = 0, ns_len = 0, name_len;
  41         const char *mode_str = aa_profile_mode_names[profile->mode];
  42         const char *ns_name = NULL;
  43         struct aa_ns *ns = profile->ns;
  44         struct aa_ns *current_ns = __aa_current_profile()->ns;
  45         char *s;
  46
  47         if (!aa_ns_visible(current_ns, ns, true))
  48                 return -EACCES;
  49
  50         ns_name = aa_ns_name(current_ns, ns, true);
  51         ns_len = strlen(ns_name);
  52
  53         /* if the visible ns_name is > 0 increase size for : :// seperator */
  54         if (ns_len)
  55                 ns_len += 4;
  56
  57         /* unconfined profiles don't have a mode string appended */
  58         if (!unconfined(profile))
  59                 mode_len = strlen(mode_str) + 3;        /* + 3 for _() */
  60
  61         name_len = strlen(profile->base.hname);
  62         len = mode_len + ns_len + name_len + 1;     /* + 1 for \n */
  63         s = str = kmalloc(len + 1, GFP_KERNEL);     /* + 1 \0 */
  64         if (!str)
  65                 return -ENOMEM;
  66
  67         if (ns_len) {
  68                 /* skip over prefix current_ns->base.hname and separating // */
  69                 sprintf(s, ":%s://", ns_name);
  70                 s += ns_len;
  71         }
  72         if (unconfined(profile))
  73                 /* mode string not being appended */
  74                 sprintf(s, "%s\n", profile->base.hname);
  75         else
  76                 sprintf(s, "%s (%s)\n", profile->base.hname, mode_str);
  77         *string = str;
  78
  79         /* NOTE: len does not include \0 of string, not saved as part of file */
  80         return len;
  81 }
  82
  83 /**
  84  * split_token_from_name - separate a string of form  <token>^<name>
  85  * @op: operation being checked
  86  * @args: string to parse  (NOT NULL)
  87  * @token: stores returned parsed token value  (NOT NULL)
  88  *
  89  * Returns: start position of name after token else NULL on failure
  90  */
  91 static char *split_token_from_name(const char *op, char *args, u64 *token)
  92 {
  93         char *name;
  94
  95         *token = simple_strtoull(args, &name, 16);
  96         if ((name == args) || *name != '^') {
  97                 AA_ERROR("%s: Invalid input '%s'", op, args);
  98                 return ERR_PTR(-EINVAL);
  99         }
 100
 101         name++;                 /* skip ^ */
 102         if (!*name)
 103                 name = NULL;
 104         return name;
 105 }
 106
 107 /**
 108  * aa_setprocattr_chagnehat - handle procattr interface to change_hat
 109  * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
 110  * @size: size of the args
 111  * @test: true if this is a test of change_hat permissions
 112  *
 113  * Returns: %0 or error code if change_hat fails
 114  */
 115 int aa_setprocattr_changehat(char *args, size_t size, int test)
 116 {
 117         char *hat;
 118         u64 token;
 119         const char *hats[16];           /* current hard limit on # of names */
 120         int count = 0;
 121
 122         hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
 123         if (IS_ERR(hat))
 124                 return PTR_ERR(hat);
 125
 126         if (!hat && !token) {
 127                 AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
 128                 return -EINVAL;
 129         }
 130
 131         if (hat) {
 132                 /* set up hat name vector, args guaranteed null terminated
 133                  * at args[size] by setprocattr.
 134                  *
 135                  * If there are multiple hat names in the buffer each is
 136                  * separated by a \0.  Ie. userspace writes them pre tokenized
 137                  */
 138                 char *end = args + size;
 139                 for (count = 0; (hat < end) && count < 16; ++count) {
 140                         char *next = hat + strlen(hat) + 1;
 141                         hats[count] = hat;
 142                         AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
 143                                  , __func__, current->pid, token, count, hat);
 144                         hat = next;
 145                 }
 146         } else
 147                 AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
 148                          __func__, current->pid, token, count, "<NULL>");
 149
 150         return aa_change_hat(hats, count, token, test);
 151 }