Huw Davies | cb72d38 | 2016-06-27 15:02:46 -0400 | [diff] [blame] | 1 | /* |
| 2 | * CALIPSO - Common Architecture Label IPv6 Security Option |
| 3 | * |
| 4 | * This is an implementation of the CALIPSO protocol as specified in |
| 5 | * RFC 5570. |
| 6 | * |
| 7 | * Authors: Paul Moore <paul.moore@hp.com> |
| 8 | * Huw Davies <huw@codeweavers.com> |
| 9 | * |
| 10 | */ |
| 11 | |
| 12 | /* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 |
| 13 | * (c) Copyright Huw Davies <huw@codeweavers.com>, 2015 |
| 14 | * |
| 15 | * This program is free software; you can redistribute it and/or modify |
| 16 | * it under the terms of the GNU General Public License as published by |
| 17 | * the Free Software Foundation; either version 2 of the License, or |
| 18 | * (at your option) any later version. |
| 19 | * |
| 20 | * This program is distributed in the hope that it will be useful, |
| 21 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 22 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| 23 | * the GNU General Public License for more details. |
| 24 | * |
| 25 | * You should have received a copy of the GNU General Public License |
| 26 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| 27 | * |
| 28 | */ |
| 29 | |
| 30 | #include <linux/init.h> |
| 31 | #include <linux/types.h> |
| 32 | #include <linux/rcupdate.h> |
| 33 | #include <linux/list.h> |
| 34 | #include <linux/spinlock.h> |
| 35 | #include <linux/string.h> |
| 36 | #include <linux/jhash.h> |
| 37 | #include <linux/audit.h> |
| 38 | #include <linux/slab.h> |
| 39 | #include <net/ip.h> |
| 40 | #include <net/icmp.h> |
| 41 | #include <net/tcp.h> |
| 42 | #include <net/netlabel.h> |
| 43 | #include <net/calipso.h> |
| 44 | #include <linux/atomic.h> |
| 45 | #include <linux/bug.h> |
| 46 | #include <asm/unaligned.h> |
| 47 | |
| 48 | /* List of available DOI definitions */ |
| 49 | static DEFINE_SPINLOCK(calipso_doi_list_lock); |
| 50 | static LIST_HEAD(calipso_doi_list); |
| 51 | |
| 52 | /* DOI List Functions |
| 53 | */ |
| 54 | |
| 55 | /** |
| 56 | * calipso_doi_search - Searches for a DOI definition |
| 57 | * @doi: the DOI to search for |
| 58 | * |
| 59 | * Description: |
| 60 | * Search the DOI definition list for a DOI definition with a DOI value that |
| 61 | * matches @doi. The caller is responsible for calling rcu_read_[un]lock(). |
| 62 | * Returns a pointer to the DOI definition on success and NULL on failure. |
| 63 | */ |
| 64 | static struct calipso_doi *calipso_doi_search(u32 doi) |
| 65 | { |
| 66 | struct calipso_doi *iter; |
| 67 | |
| 68 | list_for_each_entry_rcu(iter, &calipso_doi_list, list) |
| 69 | if (iter->doi == doi && atomic_read(&iter->refcount)) |
| 70 | return iter; |
| 71 | return NULL; |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * calipso_doi_add - Add a new DOI to the CALIPSO protocol engine |
| 76 | * @doi_def: the DOI structure |
| 77 | * @audit_info: NetLabel audit information |
| 78 | * |
| 79 | * Description: |
| 80 | * The caller defines a new DOI for use by the CALIPSO engine and calls this |
| 81 | * function to add it to the list of acceptable domains. The caller must |
| 82 | * ensure that the mapping table specified in @doi_def->map meets all of the |
| 83 | * requirements of the mapping type (see calipso.h for details). Returns |
| 84 | * zero on success and non-zero on failure. |
| 85 | * |
| 86 | */ |
| 87 | static int calipso_doi_add(struct calipso_doi *doi_def, |
| 88 | struct netlbl_audit *audit_info) |
| 89 | { |
| 90 | int ret_val = -EINVAL; |
| 91 | u32 doi; |
| 92 | u32 doi_type; |
| 93 | struct audit_buffer *audit_buf; |
| 94 | |
| 95 | doi = doi_def->doi; |
| 96 | doi_type = doi_def->type; |
| 97 | |
| 98 | if (doi_def->doi == CALIPSO_DOI_UNKNOWN) |
| 99 | goto doi_add_return; |
| 100 | |
| 101 | atomic_set(&doi_def->refcount, 1); |
| 102 | |
| 103 | spin_lock(&calipso_doi_list_lock); |
| 104 | if (calipso_doi_search(doi_def->doi)) { |
| 105 | spin_unlock(&calipso_doi_list_lock); |
| 106 | ret_val = -EEXIST; |
| 107 | goto doi_add_return; |
| 108 | } |
| 109 | list_add_tail_rcu(&doi_def->list, &calipso_doi_list); |
| 110 | spin_unlock(&calipso_doi_list_lock); |
| 111 | ret_val = 0; |
| 112 | |
| 113 | doi_add_return: |
| 114 | audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_ADD, audit_info); |
| 115 | if (audit_buf) { |
| 116 | const char *type_str; |
| 117 | |
| 118 | switch (doi_type) { |
| 119 | case CALIPSO_MAP_PASS: |
| 120 | type_str = "pass"; |
| 121 | break; |
| 122 | default: |
| 123 | type_str = "(unknown)"; |
| 124 | } |
| 125 | audit_log_format(audit_buf, |
| 126 | " calipso_doi=%u calipso_type=%s res=%u", |
| 127 | doi, type_str, ret_val == 0 ? 1 : 0); |
| 128 | audit_log_end(audit_buf); |
| 129 | } |
| 130 | |
| 131 | return ret_val; |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * calipso_doi_free - Frees a DOI definition |
| 136 | * @doi_def: the DOI definition |
| 137 | * |
| 138 | * Description: |
| 139 | * This function frees all of the memory associated with a DOI definition. |
| 140 | * |
| 141 | */ |
| 142 | static void calipso_doi_free(struct calipso_doi *doi_def) |
| 143 | { |
| 144 | kfree(doi_def); |
| 145 | } |
| 146 | |
Huw Davies | a5e3449 | 2016-06-27 15:02:47 -0400 | [diff] [blame] | 147 | /** |
| 148 | * calipso_doi_free_rcu - Frees a DOI definition via the RCU pointer |
| 149 | * @entry: the entry's RCU field |
| 150 | * |
| 151 | * Description: |
| 152 | * This function is designed to be used as a callback to the call_rcu() |
| 153 | * function so that the memory allocated to the DOI definition can be released |
| 154 | * safely. |
| 155 | * |
| 156 | */ |
| 157 | static void calipso_doi_free_rcu(struct rcu_head *entry) |
| 158 | { |
| 159 | struct calipso_doi *doi_def; |
| 160 | |
| 161 | doi_def = container_of(entry, struct calipso_doi, rcu); |
| 162 | calipso_doi_free(doi_def); |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * calipso_doi_getdef - Returns a reference to a valid DOI definition |
| 167 | * @doi: the DOI value |
| 168 | * |
| 169 | * Description: |
| 170 | * Searches for a valid DOI definition and if one is found it is returned to |
| 171 | * the caller. Otherwise NULL is returned. The caller must ensure that |
| 172 | * calipso_doi_putdef() is called when the caller is done. |
| 173 | * |
| 174 | */ |
| 175 | static struct calipso_doi *calipso_doi_getdef(u32 doi) |
| 176 | { |
| 177 | struct calipso_doi *doi_def; |
| 178 | |
| 179 | rcu_read_lock(); |
| 180 | doi_def = calipso_doi_search(doi); |
| 181 | if (!doi_def) |
| 182 | goto doi_getdef_return; |
| 183 | if (!atomic_inc_not_zero(&doi_def->refcount)) |
| 184 | doi_def = NULL; |
| 185 | |
| 186 | doi_getdef_return: |
| 187 | rcu_read_unlock(); |
| 188 | return doi_def; |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * calipso_doi_putdef - Releases a reference for the given DOI definition |
| 193 | * @doi_def: the DOI definition |
| 194 | * |
| 195 | * Description: |
| 196 | * Releases a DOI definition reference obtained from calipso_doi_getdef(). |
| 197 | * |
| 198 | */ |
| 199 | static void calipso_doi_putdef(struct calipso_doi *doi_def) |
| 200 | { |
| 201 | if (!doi_def) |
| 202 | return; |
| 203 | |
| 204 | if (!atomic_dec_and_test(&doi_def->refcount)) |
| 205 | return; |
| 206 | spin_lock(&calipso_doi_list_lock); |
| 207 | list_del_rcu(&doi_def->list); |
| 208 | spin_unlock(&calipso_doi_list_lock); |
| 209 | |
| 210 | call_rcu(&doi_def->rcu, calipso_doi_free_rcu); |
| 211 | } |
| 212 | |
Huw Davies | e1ce69d | 2016-06-27 15:02:48 -0400 | [diff] [blame^] | 213 | /** |
| 214 | * calipso_doi_walk - Iterate through the DOI definitions |
| 215 | * @skip_cnt: skip past this number of DOI definitions, updated |
| 216 | * @callback: callback for each DOI definition |
| 217 | * @cb_arg: argument for the callback function |
| 218 | * |
| 219 | * Description: |
| 220 | * Iterate over the DOI definition list, skipping the first @skip_cnt entries. |
| 221 | * For each entry call @callback, if @callback returns a negative value stop |
| 222 | * 'walking' through the list and return. Updates the value in @skip_cnt upon |
| 223 | * return. Returns zero on success, negative values on failure. |
| 224 | * |
| 225 | */ |
| 226 | static int calipso_doi_walk(u32 *skip_cnt, |
| 227 | int (*callback)(struct calipso_doi *doi_def, |
| 228 | void *arg), |
| 229 | void *cb_arg) |
| 230 | { |
| 231 | int ret_val = -ENOENT; |
| 232 | u32 doi_cnt = 0; |
| 233 | struct calipso_doi *iter_doi; |
| 234 | |
| 235 | rcu_read_lock(); |
| 236 | list_for_each_entry_rcu(iter_doi, &calipso_doi_list, list) |
| 237 | if (atomic_read(&iter_doi->refcount) > 0) { |
| 238 | if (doi_cnt++ < *skip_cnt) |
| 239 | continue; |
| 240 | ret_val = callback(iter_doi, cb_arg); |
| 241 | if (ret_val < 0) { |
| 242 | doi_cnt--; |
| 243 | goto doi_walk_return; |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | doi_walk_return: |
| 248 | rcu_read_unlock(); |
| 249 | *skip_cnt = doi_cnt; |
| 250 | return ret_val; |
| 251 | } |
| 252 | |
Huw Davies | cb72d38 | 2016-06-27 15:02:46 -0400 | [diff] [blame] | 253 | static const struct netlbl_calipso_ops ops = { |
| 254 | .doi_add = calipso_doi_add, |
| 255 | .doi_free = calipso_doi_free, |
Huw Davies | a5e3449 | 2016-06-27 15:02:47 -0400 | [diff] [blame] | 256 | .doi_getdef = calipso_doi_getdef, |
| 257 | .doi_putdef = calipso_doi_putdef, |
Huw Davies | e1ce69d | 2016-06-27 15:02:48 -0400 | [diff] [blame^] | 258 | .doi_walk = calipso_doi_walk, |
Huw Davies | cb72d38 | 2016-06-27 15:02:46 -0400 | [diff] [blame] | 259 | }; |
| 260 | |
| 261 | /** |
| 262 | * calipso_init - Initialize the CALIPSO module |
| 263 | * |
| 264 | * Description: |
| 265 | * Initialize the CALIPSO module and prepare it for use. Returns zero on |
| 266 | * success and negative values on failure. |
| 267 | * |
| 268 | */ |
| 269 | int __init calipso_init(void) |
| 270 | { |
| 271 | netlbl_calipso_ops_register(&ops); |
| 272 | return 0; |
| 273 | } |
| 274 | |
| 275 | void calipso_exit(void) |
| 276 | { |
| 277 | netlbl_calipso_ops_register(NULL); |
| 278 | } |