sys/netlink/netlink_generic.c

   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);