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 *
lb_alloc(struct linear_buffer * lb,int len)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
lb_clear(struct linear_buffer * lb)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 *
npt_alloc(struct nl_pstate * npt,int len)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) ((struct sockaddr *)(npt_alloc(_npt, _len)))
84
85 typedef int parse_field_f(void *hdr, struct nl_pstate *npt,
86 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
102 struct nlattr_parser;
103 typedef int parse_attr_f(struct nlattr *attr, struct nl_pstate *npt,
104 const void *arg, void *target);
105 struct nlattr_parser {
106 uint16_t type; /* Attribute type */
107 uint16_t off; /* field offset in the target structure */
108 parse_attr_f *cb; /* parser function to call */
109 const void *arg;
110 };
111
112 typedef bool strict_parser_f(void *hdr, struct nl_pstate *npt);
113 typedef bool post_parser_f(void *parsed_attrs, struct nl_pstate *npt);
114
115 struct nlhdr_parser {
116 int nl_hdr_off; /* aligned netlink header size */
117 int out_hdr_off; /* target header size */
118 int fp_size;
119 int np_size;
120 const struct nlfield_parser *fp; /* array of header field parsers */
121 const struct nlattr_parser *np; /* array of attribute parsers */
122 strict_parser_f *sp; /* Pre-parse strict validation function */
123 post_parser_f *post_parse;
124 };
125
126 #define NL_DECLARE_PARSER_EXT(_name, _t, _sp, _fp, _np, _pp) \
127 static const struct nlhdr_parser _name = { \
128 .nl_hdr_off = sizeof(_t), \
129 .fp = &((_fp)[0]), \
130 .np = &((_np)[0]), \
131 .fp_size = nitems(_fp), \
132 .np_size = nitems(_np), \
133 .sp = _sp, \
134 .post_parse = _pp, \
135 }
136
137 #define NL_DECLARE_PARSER(_name, _t, _fp, _np) \
138 NL_DECLARE_PARSER_EXT(_name, _t, NULL, _fp, _np, NULL)
139
140 #define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np) \
141 NL_DECLARE_PARSER_EXT(_name, _t, _sp, _fp, _np, NULL)
142
143 #define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \
144 static const struct nlhdr_parser _name = { \
145 .nl_hdr_off = sizeof(_t), \
146 .out_hdr_off = sizeof(_o), \
147 .fp = &((_fp)[0]), \
148 .np = &((_np)[0]), \
149 .fp_size = nitems(_fp), \
150 .np_size = nitems(_np), \
151 }
152
153 #define NL_DECLARE_ATTR_PARSER_EXT(_name, _np, _pp) \
154 static const struct nlhdr_parser _name = { \
155 .np = &((_np)[0]), \
156 .np_size = nitems(_np), \
157 .post_parse = (_pp) \
158 }
159
160 #define NL_DECLARE_ATTR_PARSER(_name, _np) \
161 NL_DECLARE_ATTR_PARSER_EXT(_name, _np, NULL)
162
163 #define NL_ATTR_BMASK_SIZE 128
164 BITSET_DEFINE(nlattr_bmask, NL_ATTR_BMASK_SIZE);
165
166 void nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm);
167 bool nl_has_attr(const struct nlattr_bmask *bm, unsigned int nla_type);
168
169 int nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps,
170 int pslen, struct nl_pstate *npt, void *target);
171
172 int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt,
173 const void *arg, void *target);
174 int nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt,
175 const void *arg, void *target);
176 int nlattr_get_bool(struct nlattr *nla, struct nl_pstate *npt,
177 const void *arg, void *target);
178 int nlattr_get_uint8(struct nlattr *nla, struct nl_pstate *npt,
179 const void *arg, void *target);
180 int nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt,
181 const void *arg, void *target);
182 int nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt,
183 const void *arg, void *target);
184 int nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt,
185 const void *arg, void *target);
186 int nlattr_get_in_addr(struct nlattr *nla, struct nl_pstate *npt,
187 const void *arg, void *target);
188 int nlattr_get_in6_addr(struct nlattr *nla, struct nl_pstate *npt,
189 const void *arg, void *target);
190 int nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt,
191 const void *arg, void *target);
192 int nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt,
193 const void *arg, void *target);
194 int nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt,
195 const void *arg, void *target);
196 int nlattr_get_chara(struct nlattr *nla, struct nl_pstate *npt,
197 const void *arg, void *target);
198 int nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt,
199 const void *arg, void *target);
200 int nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt,
201 const void *arg, void *target);
202 int nlattr_get_bytes(struct nlattr *nla, struct nl_pstate *npt,
203 const void *arg, void *target);
204 int nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt,
205 const void *arg, void *target);
206 int nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt,
207 const void *arg, void *target);
208 int nlattr_get_nested_ptr(struct nlattr *nla, struct nl_pstate *npt,
209 const void *arg, void *target);
210
211 bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...);
212
213 #define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \
214 nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \
215 NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \
216 }
217
218 bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off);
219
220 void nlmsg_report_cookie(struct nl_pstate *npt, struct nlattr *nla);
221 void nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val);
222
223 /*
224 * Have it inline so compiler can optimize field accesses into
225 * the list of direct function calls without iteration.
226 */
227 static inline int
nl_parse_header(void * hdr,int len,const struct nlhdr_parser * parser,struct nl_pstate * npt,void * target)228 nl_parse_header(void *hdr, int len, const struct nlhdr_parser *parser,
229 struct nl_pstate *npt, void *target)
230 {
231 int error;
232
233 if (__predict_false(len < parser->nl_hdr_off)) {
234 if (npt->strict) {
235 nlmsg_report_err_msg(npt, "header too short: expected %d, got %d",
236 parser->nl_hdr_off, len);
237 return (EINVAL);
238 }
239
240 /* Compat with older applications: pretend there's a full header */
241 void *tmp_hdr = npt_alloc(npt, parser->nl_hdr_off);
242 if (tmp_hdr == NULL)
243 return (EINVAL);
244 memcpy(tmp_hdr, hdr, len);
245 hdr = tmp_hdr;
246 len = parser->nl_hdr_off;
247 }
248
249 if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt))
250 return (EINVAL);
251
252 /* Extract fields first */
253 for (int i = 0; i < parser->fp_size; i++) {
254 const struct nlfield_parser *fp = &parser->fp[i];
255 void *src = (char *)hdr + fp->off_in;
256 void *dst = (char *)target + fp->off_out;
257
258 error = fp->cb(src, npt, dst);
259 if (error != 0)
260 return (error);
261 }
262
263 struct nlattr *nla_head = (struct nlattr *)((char *)hdr + parser->nl_hdr_off);
264 error = nl_parse_attrs_raw(nla_head, len - parser->nl_hdr_off, parser->np,
265 parser->np_size, npt, target);
266
267 if (parser->post_parse != NULL && error == 0) {
268 if (!parser->post_parse(target, npt))
269 return (EINVAL);
270 }
271
272 return (error);
273 }
274
275 static inline int
nl_parse_nested(struct nlattr * nla,const struct nlhdr_parser * parser,struct nl_pstate * npt,void * target)276 nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser,
277 struct nl_pstate *npt, void *target)
278 {
279 struct nlattr *nla_head = (struct nlattr *)NLA_DATA(nla);
280
281 return (nl_parse_attrs_raw(nla_head, NLA_DATA_LEN(nla), parser->np,
282 parser->np_size, npt, target));
283 }
284
285 /*
286 * Checks that attributes are sorted by attribute type.
287 */
288 static inline void
nl_verify_parsers(const struct nlhdr_parser ** parser,int count)289 nl_verify_parsers(const struct nlhdr_parser **parser, int count)
290 {
291 #ifdef INVARIANTS
292 for (int i = 0; i < count; i++) {
293 const struct nlhdr_parser *p = parser[i];
294 int attr_type = 0;
295 for (int j = 0; j < p->np_size; j++) {
296 MPASS(p->np[j].type > attr_type);
297 attr_type = p->np[j].type;
298
299 /* Recurse into nested objects. */
300 if (p->np[j].cb == nlattr_get_nested ||
301 p->np[j].cb == nlattr_get_nested_ptr) {
302 const struct nlhdr_parser *np =
303 (const struct nlhdr_parser *)p->np[j].arg;
304 nl_verify_parsers(&np, 1);
305 }
306 }
307 }
308 #endif
309 }
310 void nl_verify_parsers(const struct nlhdr_parser **parser, int count);
311 #define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), nitems(_p))
312
313 static inline int
nl_parse_nlmsg(struct nlmsghdr * hdr,const struct nlhdr_parser * parser,struct nl_pstate * npt,void * target)314 nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
315 struct nl_pstate *npt, void *target)
316 {
317 return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target));
318 }
319
320 static inline void
nl_get_attrs_bmask_nlmsg(struct nlmsghdr * hdr,const struct nlhdr_parser * parser,struct nlattr_bmask * bm)321 nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
322 struct nlattr_bmask *bm)
323 {
324 struct nlattr *nla_head;
325
326 nla_head = (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off);
327 int len = hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off;
328
329 nl_get_attrs_bmask_raw(nla_head, len, bm);
330 }
331
332 #endif
333 #endif
334