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/domain.h"
  19 #include "include/procattr.h"
  20
  21
  22 /**
  23  * aa_getprocattr - Return the profile information for @profile
  24  * @profile: the profile to print profile info about  (NOT NULL)
  25  * @string: Returns - string containing the profile info (NOT NULL)
  26  *
  27  * Returns: length of @string on success else error on failure
  28  *
  29  * Requires: profile != NULL
  30  *
  31  * Creates a string containing the namespace_name://profile_name for
  32  * @profile.
  33  *
  34  * Returns: size of string placed in @string else error code on failure
  35  */
  36 int aa_getprocattr(struct aa_profile *profile, char **string)
  37 {
  38         char *str;
  39         int len = 0, mode_len = 0, ns_len = 0, name_len;
  40         const char *mode_str = aa_profile_mode_names[profile->mode];
  41         const char *ns_name = NULL;
  42         struct aa_namespace *ns = profile->ns;
  43         struct aa_namespace *current_ns = __aa_current_profile()->ns;
  44         char *s;
  45
  46         if (!aa_ns_visible(current_ns, ns))
  47                 return -EACCES;
  48
  49         ns_name = aa_ns_name(current_ns, ns);
  50         ns_len = strlen(ns_name);
  51
  52         /* if the visible ns_name is > 0 increase size for : :// seperator */
  53         if (ns_len)
  54                 ns_len += 4;
  55
  56         /* unconfined profiles don't have a mode string appended */
  57         if (!unconfined(profile))
  58                 mode_len = strlen(mode_str) + 3;        /* + 3 for _() */
  59
  60         name_len = strlen(profile->base.hname);
  61         len = mode_len + ns_len + name_len + 1;     /* + 1 for \n */
  62         s = str = kmalloc(len + 1, GFP_KERNEL);     /* + 1 \0 */
  63         if (!str)
  64                 return -ENOMEM;
  65
  66         if (ns_len) {
  67                 /* skip over prefix current_ns->base.hname and separating // */
  68                 sprintf(s, ":%s://", ns_name);
  69                 s += ns_len;
  70         }
  71         if (unconfined(profile))
  72                 /* mode string not being appended */
  73                 sprintf(s, "%s\n", profile->base.hname);
  74         else
  75                 sprintf(s, "%s (%s)\n", profile->base.hname, mode_str);
  76         *string = str;
  77
  78         /* NOTE: len does not include \0 of string, not saved as part of file */
  79         return len;
  80 }
  81
  82 /**
  83  * split_token_from_name - separate a string of form  <token>^<name>
  84  * @op: operation being checked
  85  * @args: string to parse  (NOT NULL)
  86  * @token: stores returned parsed token value  (NOT NULL)
  87  *
  88  * Returns: start position of name after token else NULL on failure
  89  */
  90 static char *split_token_from_name(int op, char *args, u64 * token)
  91 {
  92         char *name;
  93
  94         *token = simple_strtoull(args, &name, 16);
  95         if ((name == args) || *name != '^') {
  96                 AA_ERROR("%s: Invalid input '%s'", op_table[op], args);
  97                 return ERR_PTR(-EINVAL);
  98         }
  99
 100         name++;                 /* skip ^ */
 101         if (!*name)
 102                 name = NULL;
 103         return name;
 104 }
 105
 106 /**
 107  * aa_setprocattr_chagnehat - handle procattr interface to change_hat
 108  * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
 109  * @size: size of the args
 110  * @test: true if this is a test of change_hat permissions
 111  *
 112  * Returns: %0 or error code if change_hat fails
 113  */
 114 int aa_setprocattr_changehat(char *args, size_t size, int test)
 115 {
 116         char *hat;
 117         u64 token;
 118         const char *hats[16];           /* current hard limit on # of names */
 119         int count = 0;
 120
 121         hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
 122         if (IS_ERR(hat))
 123                 return PTR_ERR(hat);
 124
 125         if (!hat && !token) {
 126                 AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
 127                 return -EINVAL;
 128         }
 129
 130         if (hat) {
 131                 /* set up hat name vector, args guaranteed null terminated
 132                  * at args[size] by setprocattr.
 133                  *
 134                  * If there are multiple hat names in the buffer each is
 135                  * separated by a \0.  Ie. userspace writes them pre tokenized
 136                  */
 137                 char *end = args + size;
 138                 for (count = 0; (hat < end) && count < 16; ++count) {
 139                         char *next = hat + strlen(hat) + 1;
 140                         hats[count] = hat;
 141                         hat = next;
 142                 }
 143         }
 144
 145         AA_DEBUG("%s: Magic 0x%llx Hat '%s'\n",
 146                  __func__, token, hat ? hat : NULL);
 147
 148         return aa_change_hat(hats, count, token, test);
 149 }
 150
 151 /**
 152  * aa_setprocattr_changeprofile - handle procattr interface to changeprofile
 153  * @fqname: args received from writting to /proc/<pid>/attr/current (NOT NULL)
 154  * @onexec: true if change_profile should be delayed until exec
 155  * @test: true if this is a test of change_profile permissions
 156  *
 157  * Returns: %0 or error code if change_profile fails
 158  */
 159 int aa_setprocattr_changeprofile(char *fqname, bool onexec, int test)
 160 {
 161         char *name, *ns_name;
 162
 163         name = aa_split_fqname(fqname, &ns_name);
 164         return aa_change_profile(ns_name, name, onexec, test);
 165 }