1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 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 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include "opt_netlink.h" 29 30 #include <sys/cdefs.h> 31 #include <sys/types.h> 32 #include <sys/ck.h> 33 #include <sys/epoch.h> 34 #include <sys/eventhandler.h> 35 #include <sys/kernel.h> 36 #include <sys/jail.h> 37 #include <sys/lock.h> 38 #include <sys/malloc.h> 39 #include <sys/priv.h> 40 #include <sys/socket.h> 41 #include <sys/sx.h> 42 43 #include <netlink/netlink.h> 44 #include <netlink/netlink_ctl.h> 45 #include <netlink/netlink_generic.h> 46 #include <netlink/netlink_var.h> 47 48 #define DEBUG_MOD_NAME nl_generic 49 #define DEBUG_MAX_LEVEL LOG_DEBUG3 50 #include <netlink/netlink_debug.h> 51 _DECLARE_DEBUG(LOG_INFO); 52 53 static int dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr, 54 const struct genl_family *gf, struct nl_writer *nw); 55 56 /* 57 * Handler called by netlink subsystem when matching netlink message is received 58 */ 59 static int 60 genl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt) 61 { 62 struct nlpcb *nlp = npt->nlp; 63 struct genl_family *gf = NULL; 64 int error = 0; 65 66 int family_id = (int)hdr->nlmsg_type - GENL_MIN_ID; 67 68 if (__predict_false(family_id < 0 || (gf = genl_get_family(family_id)) == NULL)) { 69 NLP_LOG(LOG_DEBUG, nlp, "invalid message type: %d", hdr->nlmsg_type); 70 return (ENOTSUP); 71 } 72 73 if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) { 74 NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len); 75 return (EINVAL); 76 } 77 78 struct genlmsghdr *ghdr = (struct genlmsghdr *)(hdr + 1); 79 80 if (ghdr->cmd >= gf->family_cmd_size || gf->family_cmds[ghdr->cmd].cmd_cb == NULL) { 81 NLP_LOG(LOG_DEBUG, nlp, "family %s: invalid cmd %d", 82 gf->family_name, ghdr->cmd); 83 return (ENOTSUP); 84 } 85 86 struct genl_cmd *cmd = &gf->family_cmds[ghdr->cmd]; 87 88 if (cmd->cmd_priv != 0 && !nlp_has_priv(nlp, cmd->cmd_priv)) { 89 NLP_LOG(LOG_DEBUG, nlp, "family %s: cmd %d priv_check() failed", 90 gf->family_name, ghdr->cmd); 91 return (EPERM); 92 } 93 94 NLP_LOG(LOG_DEBUG2, nlp, "received family %s cmd %s(%d) len %d", 95 gf->family_name, cmd->cmd_name, ghdr->cmd, hdr->nlmsg_len); 96 97 error = cmd->cmd_cb(hdr, npt); 98 99 return (error); 100 } 101 102 static uint32_t 103 get_cmd_flags(const struct genl_cmd *cmd) 104 { 105 uint32_t flags = cmd->cmd_flags; 106 if (cmd->cmd_priv != 0) 107 flags |= GENL_ADMIN_PERM; 108 return (flags); 109 } 110 111 static int 112 dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr, 113 const struct genl_family *gf, struct nl_writer *nw) 114 { 115 if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) 116 goto enomem; 117 118 struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr); 119 ghdr_new->cmd = ghdr->cmd; 120 ghdr_new->version = gf->family_version; 121 ghdr_new->reserved = 0; 122 123 nlattr_add_string(nw, CTRL_ATTR_FAMILY_NAME, gf->family_name); 124 nlattr_add_u16(nw, CTRL_ATTR_FAMILY_ID, gf->family_id); 125 nlattr_add_u32(nw, CTRL_ATTR_VERSION, gf->family_version); 126 nlattr_add_u32(nw, CTRL_ATTR_HDRSIZE, gf->family_hdrsize); 127 nlattr_add_u32(nw, CTRL_ATTR_MAXATTR, gf->family_attr_max); 128 129 if (gf->family_cmd_size > 0) { 130 int off = nlattr_add_nested(nw, CTRL_ATTR_OPS); 131 if (off == 0) 132 goto enomem; 133 for (int i = 0, cnt=0; i < gf->family_cmd_size; i++) { 134 struct genl_cmd *cmd = &gf->family_cmds[i]; 135 if (cmd->cmd_cb == NULL) 136 continue; 137 int cmd_off = nlattr_add_nested(nw, ++cnt); 138 if (cmd_off == 0) 139 goto enomem; 140 141 nlattr_add_u32(nw, CTRL_ATTR_OP_ID, cmd->cmd_num); 142 nlattr_add_u32(nw, CTRL_ATTR_OP_FLAGS, get_cmd_flags(cmd)); 143 nlattr_set_len(nw, cmd_off); 144 } 145 nlattr_set_len(nw, off); 146 } 147 if (gf->family_num_groups > 0) { 148 int off = nlattr_add_nested(nw, CTRL_ATTR_MCAST_GROUPS); 149 if (off == 0) 150 goto enomem; 151 for (int i = 0, cnt = 0; i < MAX_GROUPS; i++) { 152 struct genl_group *gg = genl_get_group(i); 153 if (gg == NULL || gg->group_family != gf) 154 continue; 155 156 int cmd_off = nlattr_add_nested(nw, ++cnt); 157 if (cmd_off == 0) 158 goto enomem; 159 nlattr_add_u32(nw, CTRL_ATTR_MCAST_GRP_ID, i + MIN_GROUP_NUM); 160 nlattr_add_string(nw, CTRL_ATTR_MCAST_GRP_NAME, gg->group_name); 161 nlattr_set_len(nw, cmd_off); 162 } 163 nlattr_set_len(nw, off); 164 } 165 if (nlmsg_end(nw)) 166 return (0); 167 enomem: 168 NL_LOG(LOG_DEBUG, "unable to dump family %s state (ENOMEM)", gf->family_name); 169 nlmsg_abort(nw); 170 return (ENOMEM); 171 } 172 173 174 /* Declare ourself as a user */ 175 static void nlctrl_notify(void *arg, const struct genl_family *gf, int action); 176 static eventhandler_tag family_event_tag; 177 178 static uint32_t ctrl_family_id; 179 static uint32_t ctrl_group_id; 180 181 struct nl_parsed_family { 182 uint32_t family_id; 183 char *family_name; 184 uint8_t version; 185 }; 186 187 #define _IN(_field) offsetof(struct genlmsghdr, _field) 188 #define _OUT(_field) offsetof(struct nl_parsed_family, _field) 189 static const struct nlfield_parser nlf_p_generic[] = { 190 { .off_in = _IN(version), .off_out = _OUT(version), .cb = nlf_get_u8 }, 191 }; 192 193 static struct nlattr_parser nla_p_generic[] = { 194 { .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(family_id), .cb = nlattr_get_uint16 }, 195 { .type = CTRL_ATTR_FAMILY_NAME , .off = _OUT(family_name), .cb = nlattr_get_string }, 196 }; 197 #undef _IN 198 #undef _OUT 199 NL_DECLARE_PARSER(genl_parser, struct genlmsghdr, nlf_p_generic, nla_p_generic); 200 201 static bool 202 match_family(const struct genl_family *gf, const struct nl_parsed_family *attrs) 203 { 204 if (gf->family_name == NULL) 205 return (false); 206 if (attrs->family_id != 0 && attrs->family_id != gf->family_id) 207 return (false); 208 if (attrs->family_name != NULL && strcmp(attrs->family_name, gf->family_name)) 209 return (false); 210 return (true); 211 } 212 213 static int 214 nlctrl_handle_getfamily(struct nlmsghdr *hdr, struct nl_pstate *npt) 215 { 216 int error = 0; 217 218 struct nl_parsed_family attrs = {}; 219 error = nl_parse_nlmsg(hdr, &genl_parser, npt, &attrs); 220 if (error != 0) 221 return (error); 222 223 struct genlmsghdr ghdr = { 224 .cmd = CTRL_CMD_NEWFAMILY, 225 }; 226 227 if (attrs.family_id != 0 || attrs.family_name != NULL) { 228 /* Resolve request */ 229 for (int i = 0; i < MAX_FAMILIES; i++) { 230 struct genl_family *gf = genl_get_family(i); 231 if (gf != NULL && match_family(gf, &attrs)) { 232 error = dump_family(hdr, &ghdr, gf, npt->nw); 233 return (error); 234 } 235 } 236 return (ENOENT); 237 } 238 239 hdr->nlmsg_flags = hdr->nlmsg_flags | NLM_F_MULTI; 240 for (int i = 0; i < MAX_FAMILIES; i++) { 241 struct genl_family *gf = genl_get_family(i); 242 if (gf != NULL && match_family(gf, &attrs)) { 243 error = dump_family(hdr, &ghdr, gf, npt->nw); 244 if (error != 0) 245 break; 246 } 247 } 248 249 if (!nlmsg_end_dump(npt->nw, error, hdr)) { 250 NL_LOG(LOG_DEBUG, "Unable to finalize the dump"); 251 return (ENOMEM); 252 } 253 254 return (error); 255 } 256 257 static void 258 nlctrl_notify(void *arg __unused, const struct genl_family *gf, int cmd) 259 { 260 struct nlmsghdr hdr = {.nlmsg_type = NETLINK_GENERIC }; 261 struct genlmsghdr ghdr = { .cmd = cmd }; 262 struct nl_writer nw = {}; 263 264 if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_GENERIC, ctrl_group_id)) { 265 dump_family(&hdr, &ghdr, gf, &nw); 266 nlmsg_flush(&nw); 267 return; 268 } 269 NL_LOG(LOG_DEBUG, "error allocating group writer"); 270 } 271 272 static const struct genl_cmd nlctrl_cmds[] = { 273 { 274 .cmd_num = CTRL_CMD_GETFAMILY, 275 .cmd_name = "GETFAMILY", 276 .cmd_cb = nlctrl_handle_getfamily, 277 .cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL, 278 }, 279 }; 280 281 static const struct nlhdr_parser *all_parsers[] = { &genl_parser }; 282 283 static void 284 genl_load_all(void *u __unused) 285 { 286 NL_VERIFY_PARSERS(all_parsers); 287 ctrl_family_id = genl_register_family(CTRL_FAMILY_NAME, 0, 2, CTRL_ATTR_MAX); 288 genl_register_cmds(CTRL_FAMILY_NAME, nlctrl_cmds, NL_ARRAY_LEN(nlctrl_cmds)); 289 ctrl_group_id = genl_register_group(CTRL_FAMILY_NAME, "notify"); 290 family_event_tag = EVENTHANDLER_REGISTER(genl_family_event, nlctrl_notify, NULL, 291 EVENTHANDLER_PRI_ANY); 292 netlink_register_proto(NETLINK_GENERIC, "NETLINK_GENERIC", genl_handle_message); 293 } 294 SYSINIT(genl_load_all, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_load_all, NULL); 295 296 static void 297 genl_unload(void *u __unused) 298 { 299 netlink_unregister_proto(NETLINK_GENERIC); 300 EVENTHANDLER_DEREGISTER(genl_family_event, family_event_tag); 301 genl_unregister_family(CTRL_FAMILY_NAME); 302 NET_EPOCH_WAIT(); 303 } 304 SYSUNINIT(genl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_unload, NULL); 305