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