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 #ifndef _NETLINK_NETLINK_MESSAGE_PARSER_H_ 29 #define _NETLINK_NETLINK_MESSAGE_PARSER_H_ 30 31 #ifdef _KERNEL 32 33 #include <sys/bitset.h> 34 35 /* 36 * It is not meant to be included directly 37 */ 38 39 /* Parsing state */ 40 struct linear_buffer { 41 char *base; /* Base allocated memory pointer */ 42 uint32_t offset; /* Currently used offset */ 43 uint32_t size; /* Total buffer size */ 44 } __aligned(_Alignof(__max_align_t)); 45 46 static inline void * 47 lb_alloc(struct linear_buffer *lb, int len) 48 { 49 len = roundup2(len, _Alignof(__max_align_t)); 50 if (lb->offset + len > lb->size) 51 return (NULL); 52 void *data = (void *)(lb->base + lb->offset); 53 lb->offset += len; 54 return (data); 55 } 56 57 static inline void 58 lb_clear(struct linear_buffer *lb) 59 { 60 memset(lb->base, 0, lb->size); 61 lb->offset = 0; 62 } 63 64 #define NL_MAX_ERROR_BUF 128 65 #define SCRATCH_BUFFER_SIZE (1024 + NL_MAX_ERROR_BUF) 66 struct nl_pstate { 67 struct linear_buffer lb; /* Per-message scratch buffer */ 68 struct nlpcb *nlp; /* Originator socket */ 69 struct nl_writer *nw; /* Message writer to use */ 70 struct nlmsghdr *hdr; /* Current parsed message header */ 71 uint32_t err_off; /* error offset from hdr start */ 72 int error; /* last operation error */ 73 char *err_msg; /* Description of last error */ 74 struct nlattr *cookie; /* NLA to return to the userspace */ 75 bool strict; /* Strict parsing required */ 76 }; 77 78 static inline void * 79 npt_alloc(struct nl_pstate *npt, int len) 80 { 81 return (lb_alloc(&npt->lb, len)); 82 } 83 #define npt_alloc_sockaddr(_npt, _len) \ 84 ((struct sockaddr *)(npt_alloc((_npt), (_len)))) 85 86 typedef int parse_field_f(void *hdr, struct nl_pstate *npt, void *target); 87 struct nlfield_parser { 88 uint16_t off_in; 89 uint16_t off_out; 90 parse_field_f *cb; 91 }; 92 static const struct nlfield_parser nlf_p_empty[] = {}; 93 94 int nlf_get_ifp(void *src, struct nl_pstate *npt, void *target); 95 int nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target); 96 int nlf_get_u8(void *src, struct nl_pstate *npt, void *target); 97 int nlf_get_u16(void *src, struct nl_pstate *npt, void *target); 98 int nlf_get_u32(void *src, struct nl_pstate *npt, void *target); 99 int nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target); 100 101 struct nlattr_parser; 102 typedef int parse_attr_f(struct nlattr *attr, struct nl_pstate *npt, 103 const void *arg, void *target); 104 struct nlattr_parser { 105 uint16_t type; /* Attribute type */ 106 uint16_t off; /* field offset in the target structure */ 107 parse_attr_f *cb; /* parser function to call */ 108 const void *arg; 109 }; 110 111 typedef bool strict_parser_f(void *hdr, struct nl_pstate *npt); 112 typedef bool post_parser_f(void *parsed_attrs, struct nl_pstate *npt); 113 114 struct nlhdr_parser { 115 u_int nl_hdr_off; /* aligned netlink header size */ 116 u_int out_hdr_off; /* target header size */ 117 u_int fp_size; 118 u_int np_size; 119 const struct nlfield_parser *fp; /* array of header field parsers */ 120 const struct nlattr_parser *np; /* array of attribute parsers */ 121 strict_parser_f *sp; /* Pre-parse strict validation function */ 122 post_parser_f *post_parse; 123 }; 124 125 #define NL_DECLARE_PARSER_EXT(_name, _t, _sp, _fp, _np, _pp) \ 126 static const struct nlhdr_parser _name = { \ 127 .nl_hdr_off = sizeof(_t), \ 128 .fp = &((_fp)[0]), \ 129 .np = &((_np)[0]), \ 130 .fp_size = nitems(_fp), \ 131 .np_size = nitems(_np), \ 132 .sp = _sp, \ 133 .post_parse = _pp, \ 134 } 135 136 #define NL_DECLARE_PARSER(_name, _t, _fp, _np) \ 137 NL_DECLARE_PARSER_EXT(_name, _t, NULL, _fp, _np, NULL) 138 139 #define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np) \ 140 NL_DECLARE_PARSER_EXT(_name, _t, _sp, _fp, _np, NULL) 141 142 #define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \ 143 static const struct nlhdr_parser _name = { \ 144 .nl_hdr_off = sizeof(_t), \ 145 .out_hdr_off = sizeof(_o), \ 146 .fp = &((_fp)[0]), \ 147 .np = &((_np)[0]), \ 148 .fp_size = nitems(_fp), \ 149 .np_size = nitems(_np), \ 150 } 151 152 #define NL_DECLARE_ATTR_PARSER_EXT(_name, _np, _pp) \ 153 static const struct nlhdr_parser _name = { \ 154 .np = &((_np)[0]), \ 155 .np_size = nitems(_np), \ 156 .post_parse = (_pp) \ 157 } 158 159 #define NL_DECLARE_ATTR_PARSER(_name, _np) \ 160 NL_DECLARE_ATTR_PARSER_EXT(_name, _np, NULL) 161 162 #define NL_ATTR_BMASK_SIZE 128 163 BITSET_DEFINE(nlattr_bmask, NL_ATTR_BMASK_SIZE); 164 165 void nl_get_attrs_bmask_raw(struct nlattr *nla_head, uint32_t len, 166 struct nlattr_bmask *bm); 167 bool nl_has_attr(const struct nlattr_bmask *bm, uint16_t nla_type); 168 169 int nl_parse_attrs_raw(struct nlattr *nla_head, uint16_t len, 170 const struct nlattr_parser *ps, u_int pslen, struct nl_pstate *npt, 171 void *target); 172 173 int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, 174 const void *arg, void *target); 175 int nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, 176 const void *arg, void *target); 177 int nlattr_get_bool(struct nlattr *nla, struct nl_pstate *npt, 178 const void *arg, void *target); 179 int nlattr_get_uint8(struct nlattr *nla, struct nl_pstate *npt, 180 const void *arg, void *target); 181 int nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, 182 const void *arg, void *target); 183 int nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, 184 const void *arg, void *target); 185 int nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, 186 const void *arg, void *target); 187 int nlattr_get_in_addr(struct nlattr *nla, struct nl_pstate *npt, 188 const void *arg, void *target); 189 int nlattr_get_in6_addr(struct nlattr *nla, struct nl_pstate *npt, 190 const void *arg, void *target); 191 int nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, 192 const void *arg, void *target); 193 int nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, 194 const void *arg, void *target); 195 int nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, 196 const void *arg, void *target); 197 int nlattr_get_chara(struct nlattr *nla, struct nl_pstate *npt, 198 const void *arg, void *target); 199 int nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, 200 const void *arg, void *target); 201 int nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, 202 const void *arg, void *target); 203 int nlattr_get_bytes(struct nlattr *nla, struct nl_pstate *npt, 204 const void *arg, void *target); 205 int nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, 206 const void *arg, void *target); 207 int nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, 208 const void *arg, void *target); 209 int nlattr_get_nested_ptr(struct nlattr *nla, struct nl_pstate *npt, 210 const void *arg, void *target); 211 212 bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...) 213 __printflike(2, 3); 214 215 #define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \ 216 nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \ 217 NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \ 218 } 219 220 bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off); 221 222 void nlmsg_report_cookie(struct nl_pstate *npt, struct nlattr *nla); 223 void nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val); 224 225 /* 226 * Have it inline so compiler can optimize field accesses into 227 * the list of direct function calls without iteration. 228 */ 229 static inline int 230 nl_parse_header(void *hdr, uint32_t len, const struct nlhdr_parser *parser, 231 struct nl_pstate *npt, void *target) 232 { 233 int error; 234 235 if (__predict_false(len < parser->nl_hdr_off)) { 236 void *tmp_hdr; 237 238 if (npt->strict) { 239 nlmsg_report_err_msg(npt, 240 "header too short: expected %d, got %d", 241 parser->nl_hdr_off, len); 242 return (EINVAL); 243 } 244 245 /* 246 * Compatibility with older applications: 247 * pretend there's a full header. 248 */ 249 tmp_hdr = npt_alloc(npt, parser->nl_hdr_off); 250 if (tmp_hdr == NULL) 251 return (EINVAL); 252 memcpy(tmp_hdr, hdr, len); 253 hdr = tmp_hdr; 254 len = parser->nl_hdr_off; 255 } 256 257 if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt)) 258 return (EINVAL); 259 260 /* Extract fields first */ 261 for (u_int i = 0; i < parser->fp_size; i++) { 262 const struct nlfield_parser *fp = &parser->fp[i]; 263 void *src = (char *)hdr + fp->off_in; 264 void *dst = (char *)target + fp->off_out; 265 266 error = fp->cb(src, npt, dst); 267 if (error != 0) 268 return (error); 269 } 270 271 error = nl_parse_attrs_raw( 272 (struct nlattr *)((char *)hdr + parser->nl_hdr_off), 273 len - parser->nl_hdr_off, parser->np, parser->np_size, npt, target); 274 275 if (parser->post_parse != NULL && error == 0) { 276 if (!parser->post_parse(target, npt)) 277 return (EINVAL); 278 } 279 280 return (error); 281 } 282 283 static inline int 284 nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser, 285 struct nl_pstate *npt, void *target) 286 { 287 return (nl_parse_attrs_raw((struct nlattr *)NLA_DATA(nla), 288 NLA_DATA_LEN(nla), parser->np, parser->np_size, npt, target)); 289 } 290 291 /* 292 * Checks that attributes are sorted by attribute type. 293 */ 294 static inline void 295 nl_verify_parsers(const struct nlhdr_parser **parser, int count) 296 { 297 #ifdef INVARIANTS 298 for (int i = 0; i < count; i++) { 299 const struct nlhdr_parser *p = parser[i]; 300 int attr_type = 0; 301 for (int j = 0; j < p->np_size; j++) { 302 MPASS(p->np[j].type > attr_type); 303 attr_type = p->np[j].type; 304 305 /* Recurse into nested objects. */ 306 if (p->np[j].cb == nlattr_get_nested || 307 p->np[j].cb == nlattr_get_nested_ptr) { 308 const struct nlhdr_parser *np = 309 (const struct nlhdr_parser *)p->np[j].arg; 310 nl_verify_parsers(&np, 1); 311 } 312 } 313 } 314 #endif 315 } 316 void nl_verify_parsers(const struct nlhdr_parser **parser, int count); 317 #define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), nitems(_p)) 318 319 static inline int 320 nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser, 321 struct nl_pstate *npt, void *target) 322 { 323 return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, 324 npt, target)); 325 } 326 327 static inline void 328 nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr, 329 const struct nlhdr_parser *parser, struct nlattr_bmask *bm) 330 { 331 nl_get_attrs_bmask_raw( 332 (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off), 333 hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off, bm); 334 } 335 336 #endif 337 #endif 338