LXR linux/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 */
  33int 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 */
  78static 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 */
 102int 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}
 139