security/apparmor/procattr.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AppArmor security module
   4  *
   5  * This file contains AppArmor /proc/<pid>/attr/ interface functions
   6  *
   7  * Copyright (C) 1998-2008 Novell/SUSE
   8  * Copyright 2009-2010 Canonical Ltd.
   9  */
  10
  11 #include "include/apparmor.h"
  12 #include "include/cred.h"
  13 #include "include/policy.h"
  14 #include "include/policy_ns.h"
  15 #include "include/domain.h"
  16 #include "include/procattr.h"
  17
  18
  19 /**
  20  * aa_getprocattr - Return the profile information for @profile
  21  * @profile: the profile to print profile info about  (NOT NULL)
  22  * @string: Returns - string containing the profile info (NOT NULL)
  23  *
  24  * Returns: length of @string on success else error on failure
  25  *
  26  * Requires: profile != NULL
  27  *
  28  * Creates a string containing the namespace_name://profile_name for
  29  * @profile.
  30  *
  31  * Returns: size of string placed in @string else error code on failure
  32  */
  33 int aa_getprocattr(struct aa_label *label, char **string)
  34 {
  35         struct aa_ns *ns = labels_ns(label);
  36         struct aa_ns *current_ns = aa_get_current_ns();
  37         int len;
  38
  39         if (!aa_ns_visible(current_ns, ns, true)) {
  40                 aa_put_ns(current_ns);
  41                 return -EACCES;
  42         }
  43
  44         len = aa_label_snxprint(NULL, 0, current_ns, label,
  45                                 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
  46                                 FLAG_HIDDEN_UNCONFINED);
  47         AA_BUG(len < 0);
  48
  49         *string = kmalloc(len + 2, GFP_KERNEL);
  50         if (!*string) {
  51                 aa_put_ns(current_ns);
  52                 return -ENOMEM;
  53         }
  54
  55         len = aa_label_snxprint(*string, len + 2, current_ns, label,
  56                                 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
  57                                 FLAG_HIDDEN_UNCONFINED);
  58         if (len < 0) {
  59                 aa_put_ns(current_ns);
  60                 return len;
  61         }
  62
  63         (*string)[len] = '\n';
  64         (*string)[len + 1] = 0;
  65
  66         aa_put_ns(current_ns);
  67         return len + 1;
  68 }
  69
  70 /**
  71  * split_token_from_name - separate a string of form  <token>^<name>
  72  * @op: operation being checked
  73  * @args: string to parse  (NOT NULL)
  74  * @token: stores returned parsed token value  (NOT NULL)
  75  *
  76  * Returns: start position of name after token else NULL on failure
  77  */
  78 static char *split_token_from_name(const char *op, char *args, u64 *token)
  79 {
  80         char *name;
  81
  82         *token = simple_strtoull(args, &name, 16);
  83         if ((name == args) || *name != '^') {
  84                 AA_ERROR("%s: Invalid input '%s'", op, args);
  85                 return ERR_PTR(-EINVAL);
  86         }
  87
  88         name++;                 /* skip ^ */
  89         if (!*name)
  90                 name = NULL;
  91         return name;
  92 }
  93
  94 /**
  95  * aa_setprocattr_chagnehat - handle procattr interface to change_hat
  96  * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
  97  * @size: size of the args
  98  * @flags: set of flags governing behavior
  99  *
 100  * Returns: %0 or error code if change_hat fails
 101  */
 102 int aa_setprocattr_changehat(char *args, size_t size, int flags)
 103 {
 104         char *hat;
 105         u64 token;
 106         const char *hats[16];           /* current hard limit on # of names */
 107         int count = 0;
 108
 109         hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
 110         if (IS_ERR(hat))
 111                 return PTR_ERR(hat);
 112
 113         if (!hat && !token) {
 114                 AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
 115                 return -EINVAL;
 116         }
 117
 118         if (hat) {
 119                 /* set up hat name vector, args guaranteed null terminated
 120                  * at args[size] by setprocattr.
 121                  *
 122                  * If there are multiple hat names in the buffer each is
 123                  * separated by a \0.  Ie. userspace writes them pre tokenized
 124                  */
 125                 char *end = args + size;
 126                 for (count = 0; (hat < end) && count < 16; ++count) {
 127                         char *next = hat + strlen(hat) + 1;
 128                         hats[count] = hat;
 129                         AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
 130                                  , __func__, current->pid, token, count, hat);
 131                         hat = next;
 132                 }
 133         } else
 134                 AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
 135                          __func__, current->pid, token, count, "<NULL>");
 136
 137         return aa_change_hat(hats, count, token, flags);
 138 }