| 1 | /* $NetBSD: secmodel.c,v 1.2 2014/11/04 16:01:58 maxv Exp $ */ |
| 2 | /*- |
| 3 | * Copyright (c) 2011 Elad Efrat <elad@NetBSD.org> |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * 3. The name of the author may not be used to endorse or promote products |
| 15 | * derived from this software without specific prior written permission. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | */ |
| 28 | |
| 29 | #include <sys/types.h> |
| 30 | #include <sys/param.h> |
| 31 | #include <sys/errno.h> |
| 32 | |
| 33 | #include <sys/atomic.h> |
| 34 | #include <sys/kauth.h> |
| 35 | #include <sys/kmem.h> |
| 36 | #include <sys/queue.h> |
| 37 | #include <sys/rwlock.h> |
| 38 | #include <secmodel/secmodel.h> |
| 39 | #include <prop/proplib.h> |
| 40 | |
| 41 | /* List of secmodels, parameters, and lock. */ |
| 42 | static LIST_HEAD(, secmodel_descr) secmodels = |
| 43 | LIST_HEAD_INITIALIZER(secmodels); |
| 44 | static unsigned int secmodel_copy_cred_on_fork = false; |
| 45 | static krwlock_t secmodels_lock; |
| 46 | static int nsecmodels = 0; /* number of registered secmodels */ |
| 47 | |
| 48 | static int secmodel_plug(secmodel_t); |
| 49 | static int secmodel_unplug(secmodel_t); |
| 50 | |
| 51 | int |
| 52 | secmodel_nsecmodels(void) |
| 53 | { |
| 54 | |
| 55 | return nsecmodels; |
| 56 | } |
| 57 | |
| 58 | void |
| 59 | secmodel_init(void) |
| 60 | { |
| 61 | |
| 62 | rw_init(&secmodels_lock); |
| 63 | |
| 64 | secmodel_copy_cred_on_fork = false; |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * Register a new secmodel. |
| 69 | */ |
| 70 | int |
| 71 | secmodel_register(secmodel_t *secmodel, const char *id, const char *name, |
| 72 | prop_dictionary_t behavior, |
| 73 | secmodel_eval_t eval, secmodel_setinfo_t setinfo) |
| 74 | { |
| 75 | int err; |
| 76 | secmodel_t sm; |
| 77 | |
| 78 | sm = kmem_alloc(sizeof(*sm), KM_SLEEP); |
| 79 | |
| 80 | sm->sm_id = id; |
| 81 | sm->sm_name = name; |
| 82 | sm->sm_behavior = behavior; |
| 83 | sm->sm_eval = eval; |
| 84 | sm->sm_setinfo = setinfo; |
| 85 | |
| 86 | err = secmodel_plug(sm); |
| 87 | if (err == 0) { |
| 88 | atomic_inc_uint(&nsecmodels); |
| 89 | } else { |
| 90 | kmem_free(sm, sizeof(*sm)); |
| 91 | sm = NULL; |
| 92 | } |
| 93 | |
| 94 | *secmodel = sm; |
| 95 | return err; |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * Deregister a secmodel. |
| 100 | */ |
| 101 | int |
| 102 | secmodel_deregister(secmodel_t sm) |
| 103 | { |
| 104 | int error; |
| 105 | |
| 106 | error = secmodel_unplug(sm); |
| 107 | if (error == 0) { |
| 108 | atomic_dec_uint(&nsecmodels); |
| 109 | kmem_free(sm, sizeof(*sm)); |
| 110 | } |
| 111 | |
| 112 | return error; |
| 113 | } |
| 114 | |
| 115 | /* |
| 116 | * Lookup a secmodel by its id. |
| 117 | * |
| 118 | * Requires "secmodels_lock" handling by the caller. |
| 119 | */ |
| 120 | static secmodel_t |
| 121 | secmodel_lookup(const char *id) |
| 122 | { |
| 123 | secmodel_t tsm; |
| 124 | |
| 125 | KASSERT(rw_lock_held(&secmodels_lock)); |
| 126 | |
| 127 | LIST_FOREACH(tsm, &secmodels, sm_list) { |
| 128 | if (strcasecmp(tsm->sm_id, id) == 0) { |
| 129 | return tsm; |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | return NULL; |
| 134 | } |
| 135 | |
| 136 | /* |
| 137 | * Adjust system-global secmodel behavior following the addition |
| 138 | * or removal of a secmodel. |
| 139 | * |
| 140 | * Requires "secmodels_lock" to be held by the caller. |
| 141 | */ |
| 142 | static void |
| 143 | secmodel_adjust_behavior(secmodel_t sm, bool added) |
| 144 | { |
| 145 | bool r, b; |
| 146 | |
| 147 | KASSERT(rw_write_held(&secmodels_lock)); |
| 148 | |
| 149 | #define ADJUST_COUNTER(which, added) \ |
| 150 | do { \ |
| 151 | if (added) { \ |
| 152 | (which)++; \ |
| 153 | } else { \ |
| 154 | if ((which) > 0) \ |
| 155 | (which)--; \ |
| 156 | } \ |
| 157 | } while (/*CONSTCOND*/0) |
| 158 | |
| 159 | /* Copy credentials on fork? */ |
| 160 | r = prop_dictionary_get_bool(sm->sm_behavior, "copy-cred-on-fork" , &b); |
| 161 | if (r) { |
| 162 | ADJUST_COUNTER(secmodel_copy_cred_on_fork, added); |
| 163 | } |
| 164 | |
| 165 | #undef ADJUST_COUNTER |
| 166 | } |
| 167 | |
| 168 | static int |
| 169 | secmodel_plug(secmodel_t sm) |
| 170 | { |
| 171 | secmodel_t tsm; |
| 172 | int error = 0; |
| 173 | |
| 174 | if (sm == NULL) |
| 175 | return EFAULT; |
| 176 | |
| 177 | /* Check if the secmodel is already present. */ |
| 178 | rw_enter(&secmodels_lock, RW_WRITER); |
| 179 | tsm = secmodel_lookup(sm->sm_id); |
| 180 | if (tsm != NULL) { |
| 181 | error = EEXIST; |
| 182 | goto out; |
| 183 | } |
| 184 | |
| 185 | /* Add the secmodel. */ |
| 186 | LIST_INSERT_HEAD(&secmodels, sm, sm_list); |
| 187 | |
| 188 | /* Adjust behavior. */ |
| 189 | secmodel_adjust_behavior(sm, true); |
| 190 | |
| 191 | out: |
| 192 | /* Unlock the secmodels list. */ |
| 193 | rw_exit(&secmodels_lock); |
| 194 | |
| 195 | return error; |
| 196 | } |
| 197 | |
| 198 | static int |
| 199 | secmodel_unplug(secmodel_t sm) |
| 200 | { |
| 201 | secmodel_t tsm; |
| 202 | int error = 0; |
| 203 | |
| 204 | if (sm == NULL) |
| 205 | return EFAULT; |
| 206 | |
| 207 | /* Make sure the secmodel is present. */ |
| 208 | rw_enter(&secmodels_lock, RW_WRITER); |
| 209 | tsm = secmodel_lookup(sm->sm_id); |
| 210 | if (tsm == NULL) { |
| 211 | error = ENOENT; |
| 212 | goto out; |
| 213 | } |
| 214 | |
| 215 | /* Remove the secmodel. */ |
| 216 | LIST_REMOVE(tsm, sm_list); |
| 217 | |
| 218 | /* Adjust behavior. */ |
| 219 | secmodel_adjust_behavior(tsm, false); |
| 220 | |
| 221 | out: |
| 222 | /* Unlock the secmodels list. */ |
| 223 | rw_exit(&secmodels_lock); |
| 224 | |
| 225 | return error; |
| 226 | } |
| 227 | |
| 228 | /* XXX TODO */ |
| 229 | int |
| 230 | secmodel_setinfo(const char *id, void *v, int *err) |
| 231 | { |
| 232 | |
| 233 | return EOPNOTSUPP; |
| 234 | } |
| 235 | |
| 236 | int |
| 237 | secmodel_eval(const char *id, const char *what, void *arg, void *ret) |
| 238 | { |
| 239 | secmodel_t sm; |
| 240 | int error = 0; |
| 241 | |
| 242 | rw_enter(&secmodels_lock, RW_READER); |
| 243 | sm = secmodel_lookup(id); |
| 244 | if (sm == NULL) { |
| 245 | error = EINVAL; |
| 246 | goto out; |
| 247 | } |
| 248 | |
| 249 | if (sm->sm_eval == NULL) { |
| 250 | error = ENOENT; |
| 251 | goto out; |
| 252 | } |
| 253 | |
| 254 | if (ret == NULL) { |
| 255 | error = EFAULT; |
| 256 | goto out; |
| 257 | } |
| 258 | |
| 259 | error = sm->sm_eval(what, arg, ret); |
| 260 | /* pass error from a secmodel(9) callback as a negative value */ |
| 261 | error = -error; |
| 262 | |
| 263 | out: |
| 264 | rw_exit(&secmodels_lock); |
| 265 | |
| 266 | return error; |
| 267 | } |
| 268 | |