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 <sys/cdefs.h> 29 #include <sys/types.h> 30 #include <sys/ck.h> 31 #include <sys/epoch.h> 32 #include <sys/eventhandler.h> 33 #include <sys/kernel.h> 34 #include <sys/jail.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/priv.h> 38 #include <sys/socket.h> 39 #include <sys/sx.h> 40 41 #include <netlink/netlink.h> 42 #include <netlink/netlink_ctl.h> 43 #include <netlink/netlink_generic.h> 44 #include <netlink/netlink_var.h> 45 46 #define DEBUG_MOD_NAME nl_generic 47 #define DEBUG_MAX_LEVEL LOG_DEBUG3 48 #include <netlink/netlink_debug.h> 49 _DECLARE_DEBUG(LOG_INFO); 50 51 static int dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr, 52 const struct genl_family *gf, struct nl_writer *nw); 53 54 /* 55 * Handler called by netlink subsystem when matching netlink message is received 56 */ 57 static int 58 genl_handle_message(struct nlmsghdr *hdr, struct nl_pstate *npt) 59 { 60 struct nlpcb *nlp = npt->nlp; 61 struct genl_family *gf = NULL; 62 int error = 0; 63 64 int family_id = (int)hdr->nlmsg_type - GENL_MIN_ID; 65 66 if (__predict_false(family_id < 0 || (gf = genl_get_family(family_id)) == NULL)) { 67 NLP_LOG(LOG_DEBUG, nlp, "invalid message type: %d", hdr->nlmsg_type); 68 return (ENOTSUP); 69 } 70 71 if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) { 72 NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len); 73 return (EINVAL); 74 } 75 76 struct genlmsghdr *ghdr = (struct genlmsghdr *)(hdr + 1); 77 78 if (ghdr->cmd >= gf->family_cmd_size || gf->family_cmds[ghdr->cmd].cmd_cb == NULL) { 79 NLP_LOG(LOG_DEBUG, nlp, "family %s: invalid cmd %d", 80 gf->family_name, ghdr->cmd); 81 return (ENOTSUP); 82 } 83 84 struct genl_cmd *cmd = &gf->family_cmds[ghdr->cmd]; 85 86 if (cmd->cmd_priv != 0 && !nlp_has_priv(nlp, cmd->cmd_priv)) { 87 NLP_LOG(LOG_DEBUG, nlp, "family %s: cmd %d priv_check() failed", 88 gf->family_name, ghdr->cmd); 89 return (EPERM); 90 } 91 92 NLP_LOG(LOG_DEBUG2, nlp, "received family %s cmd %s(%d) len %d", 93 gf->family_name, cmd->cmd_name, ghdr->cmd, hdr->nlmsg_len); 94 95 error = cmd->cmd_cb(hdr, npt); 96 97 return (error); 98 } 99 100 static uint32_t 101 get_cmd_flags(const struct genl_cmd *cmd) 102 { 103 uint32_t flags = cmd->cmd_flags; 104 if (cmd->cmd_priv != 0) 105 flags |= GENL_ADMIN_PERM; 106 return (flags); 107 } 108 109 static int 110 dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr, 111 const struct genl_family *gf, struct nl_writer *nw) 112 { 113 if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) 114 goto enomem; 115 116 struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr); 117 ghdr_new->cmd = ghdr->cmd; 118 ghdr_new->version = gf->family_version; 119 ghdr_new->reserved = 0; 120 121 nlattr_add_string(nw, CTRL_ATTR_FAMILY_NAME, gf->family_name); 122 nlattr_add_u16(nw, CTRL_ATTR_FAMILY_ID, gf->family_id); 123 nlattr_add_u32(nw, CTRL_ATTR_VERSION, gf->family_version); 124 nlattr_add_u32(nw, CTRL_ATTR_HDRSIZE, gf->family_hdrsize); 125 nlattr_add_u32(nw, CTRL_ATTR_MAXATTR, gf->family_attr_max); 126 127 if (gf->family_cmd_size > 0) { 128 int off = nlattr_add_nested(nw, CTRL_ATTR_OPS); 129 if (off == 0) 130 goto enomem; 131 for (int i = 0, cnt=0; i < gf->family_cmd_size; i++) { 132 struct genl_cmd *cmd = &gf->family_cmds[i]; 133 if (cmd->cmd_cb == NULL) 134 continue; 135 int cmd_off = nlattr_add_nested(nw, ++cnt); 136 if (cmd_off == 0) 137 goto enomem; 138 139 nlattr_add_u32(nw, CTRL_ATTR_OP_ID, cmd->cmd_num); 140 nlattr_add_u32(nw, CTRL_ATTR_OP_FLAGS, get_cmd_flags(cmd)); 141 nlattr_set_len(nw, cmd_off); 142 } 143 nlattr_set_len(nw, off); 144 } 145 if (gf->family_num_groups > 0) { 146 int off = nlattr_add_nested(nw, CTRL_ATTR_MCAST_GROUPS); 147 if (off == 0) 148 goto enomem; 149 for (int i = 0, cnt = 0; i < MAX_GROUPS; i++) { 150 struct genl_group *gg = genl_get_group(i); 151 if (gg == NULL || gg->group_family != gf) 152 continue; 153 154 int cmd_off = nlattr_add_nested(nw, ++cnt); 155 if (cmd_off == 0) 156 goto enomem; 157 nlattr_add_u32(nw, CTRL_ATTR_MCAST_GRP_ID, i + MIN_GROUP_NUM); 158 nlattr_add_string(nw, CTRL_ATTR_MCAST_GRP_NAME, gg->group_name); 159 nlattr_set_len(nw, cmd_off); 160 } 161 nlattr_set_len(nw, off); 162 } 163 if (nlmsg_end(nw)) 164 return (0); 165 enomem: 166 NL_LOG(LOG_DEBUG, "unable to dump family %s state (ENOMEM)", gf->family_name); 167 nlmsg_abort(nw); 168 return (ENOMEM); 169 } 170 171 172 /* Declare ourself as a user */ 173 static void nlctrl_notify(void *arg, const struct genl_family *gf, int action); 174 static eventhandler_tag family_event_tag; 175 176 static uint32_t ctrl_family_id; 177 static uint32_t ctrl_group_id; 178 179 struct nl_parsed_family { 180 uint32_t family_id; 181 char *family_name; 182 uint8_t version; 183 }; 184 185 #define _IN(_field) offsetof(struct genlmsghdr, _field) 186 #define _OUT(_field) offsetof(struct nl_parsed_family, _field) 187 static const struct nlfield_parser nlf_p_generic[] = { 188 { .off_in = _IN(version), .off_out = _OUT(version), .cb = nlf_get_u8 }, 189 }; 190 191 static struct nlattr_parser nla_p_generic[] = { 192 { .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(family_id), .cb = nlattr_get_uint16 }, 193 { .type = CTRL_ATTR_FAMILY_NAME , .off = _OUT(family_name), .cb = nlattr_get_string }, 194 }; 195 #undef _IN 196 #undef _OUT 197 NL_DECLARE_PARSER(genl_parser, struct genlmsghdr, nlf_p_generic, nla_p_generic); 198 199 static bool 200 match_family(const struct genl_family *gf, const struct nl_parsed_family *attrs) 201 { 202 if (gf->family_name == NULL) 203 return (false); 204 if (attrs->family_id != 0 && attrs->family_id != gf->family_id) 205 return (false); 206 if (attrs->family_name != NULL && strcmp(attrs->family_name, gf->family_name)) 207 return (false); 208 return (true); 209 } 210 211 static int 212 nlctrl_handle_getfamily(struct nlmsghdr *hdr, struct nl_pstate *npt) 213 { 214 int error = 0; 215 216 struct nl_parsed_family attrs = {}; 217 error = nl_parse_nlmsg(hdr, &genl_parser, npt, &attrs); 218 if (error != 0) 219 return (error); 220 221 struct genlmsghdr ghdr = { 222 .cmd = CTRL_CMD_NEWFAMILY, 223 }; 224 225 if (attrs.family_id != 0 || attrs.family_name != NULL) { 226 /* Resolve request */ 227 for (int i = 0; i < MAX_FAMILIES; i++) { 228 struct genl_family *gf = genl_get_family(i); 229 if (gf != NULL && match_family(gf, &attrs)) { 230 error = dump_family(hdr, &ghdr, gf, npt->nw); 231 return (error); 232 } 233 } 234 return (ENOENT); 235 } 236 237 hdr->nlmsg_flags = hdr->nlmsg_flags | NLM_F_MULTI; 238 for (int i = 0; i < MAX_FAMILIES; i++) { 239 struct genl_family *gf = genl_get_family(i); 240 if (gf != NULL && match_family(gf, &attrs)) { 241 error = dump_family(hdr, &ghdr, gf, npt->nw); 242 if (error != 0) 243 break; 244 } 245 } 246 247 if (!nlmsg_end_dump(npt->nw, error, hdr)) { 248 NL_LOG(LOG_DEBUG, "Unable to finalize the dump"); 249 return (ENOMEM); 250 } 251 252 return (error); 253 } 254 255 static void 256 nlctrl_notify(void *arg __unused, const struct genl_family *gf, int cmd) 257 { 258 struct nlmsghdr hdr = {.nlmsg_type = NETLINK_GENERIC }; 259 struct genlmsghdr ghdr = { .cmd = cmd }; 260 struct nl_writer nw = {}; 261 262 if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_GENERIC, ctrl_group_id)) { 263 dump_family(&hdr, &ghdr, gf, &nw); 264 nlmsg_flush(&nw); 265 return; 266 } 267 NL_LOG(LOG_DEBUG, "error allocating group writer"); 268 } 269 270 static const struct genl_cmd nlctrl_cmds[] = { 271 { 272 .cmd_num = CTRL_CMD_GETFAMILY, 273 .cmd_name = "GETFAMILY", 274 .cmd_cb = nlctrl_handle_getfamily, 275 .cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL, 276 }, 277 }; 278 279 static const struct nlhdr_parser *all_parsers[] = { &genl_parser }; 280 281 static void 282 genl_load_all(void *u __unused) 283 { 284 NL_VERIFY_PARSERS(all_parsers); 285 ctrl_family_id = genl_register_family(CTRL_FAMILY_NAME, 0, 2, CTRL_ATTR_MAX); 286 genl_register_cmds(CTRL_FAMILY_NAME, nlctrl_cmds, NL_ARRAY_LEN(nlctrl_cmds)); 287 ctrl_group_id = genl_register_group(CTRL_FAMILY_NAME, "notify"); 288 family_event_tag = EVENTHANDLER_REGISTER(genl_family_event, nlctrl_notify, NULL, 289 EVENTHANDLER_PRI_ANY); 290 netlink_register_proto(NETLINK_GENERIC, "NETLINK_GENERIC", genl_handle_message); 291 } 292 SYSINIT(genl_load_all, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_load_all, NULL); 293 294 static void 295 genl_unload(void *u __unused) 296 { 297 netlink_unregister_proto(NETLINK_GENERIC); 298 EVENTHANDLER_DEREGISTER(genl_family_event, family_event_tag); 299 genl_unregister_family(CTRL_FAMILY_NAME); 300 NET_EPOCH_WAIT(); 301 } 302 SYSUNINIT(genl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_unload, NULL); 303