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) \
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 struct nlmsghdr *nl_alloc_compat_hdr(struct nlmsghdr *hdr, uint32_t len,
226 struct nl_pstate *npt);
227
228 /*
229 * Have it inline so compiler can optimize field accesses into
230 * the list of direct function calls without iteration.
231 */
232 static inline int
nl_parse_header(void * hdr,uint32_t len,const struct nlhdr_parser * parser,struct nl_pstate * npt,void * target)233 nl_parse_header(void *hdr, uint32_t len, const struct nlhdr_parser *parser,
234 struct nl_pstate *npt, void *target)
235 {
236 int error;
237
238 MPASS(len >= parser->nl_hdr_off);
239
240 if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt))
241 return (EINVAL);
242
243 /* Extract fields first */
244 for (u_int i = 0; i < parser->fp_size; i++) {
245 const struct nlfield_parser *fp = &parser->fp[i];
246 void *src = (char *)hdr + fp->off_in;
247 void *dst = (char *)target + fp->off_out;
248
249 error = fp->cb(src, npt, dst);
250 if (error != 0)
251 return (error);
252 }
253
254 error = nl_parse_attrs_raw(
255 (struct nlattr *)((char *)hdr + parser->nl_hdr_off),
256 len - parser->nl_hdr_off, parser->np, parser->np_size, npt, target);
257
258 if (parser->post_parse != NULL && error == 0) {
259 if (!parser->post_parse(target, npt))
260 return (EINVAL);
261 }
262
263 return (error);
264 }
265
266 static inline int
nl_parse_nested(struct nlattr * nla,const struct nlhdr_parser * parser,struct nl_pstate * npt,void * target)267 nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser,
268 struct nl_pstate *npt, void *target)
269 {
270 return (nl_parse_attrs_raw((struct nlattr *)NLA_DATA(nla),
271 NLA_DATA_LEN(nla), parser->np, parser->np_size, npt, target));
272 }
273
274 /*
275 * Checks that attributes are sorted by attribute type.
276 */
277 static inline void
nl_verify_parsers(const struct nlhdr_parser ** parser,int count)278 nl_verify_parsers(const struct nlhdr_parser **parser, int count)
279 {
280 #ifdef INVARIANTS
281 for (int i = 0; i < count; i++) {
282 const struct nlhdr_parser *p = parser[i];
283 int attr_type = 0;
284 for (int j = 0; j < p->np_size; j++) {
285 MPASS(p->np[j].type > attr_type);
286 attr_type = p->np[j].type;
287
288 /* Recurse into nested objects. */
289 if (p->np[j].cb == nlattr_get_nested ||
290 p->np[j].cb == nlattr_get_nested_ptr) {
291 const struct nlhdr_parser *np =
292 (const struct nlhdr_parser *)p->np[j].arg;
293 nl_verify_parsers(&np, 1);
294 }
295 }
296 }
297 #endif
298 }
299 void nl_verify_parsers(const struct nlhdr_parser **parser, int count);
300 #define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), nitems(_p))
301
302 static inline int
nl_parse_nlmsg(struct nlmsghdr * hdr,const struct nlhdr_parser * parser,struct nl_pstate * npt,void * target)303 nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
304 struct nl_pstate *npt, void *target)
305 {
306 if (__predict_false(hdr->nlmsg_len - sizeof(struct nlmsghdr) <
307 parser->nl_hdr_off) &&
308 ((hdr = nl_alloc_compat_hdr(hdr, parser->nl_hdr_off, npt)) == NULL))
309 return (ENOMEM);
310 return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser,
311 npt, target));
312 }
313
314 static inline void
nl_get_attrs_bmask_nlmsg(struct nlmsghdr * hdr,const struct nlhdr_parser * parser,struct nlattr_bmask * bm)315 nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr,
316 const struct nlhdr_parser *parser, struct nlattr_bmask *bm)
317 {
318 if (__predict_false(hdr->nlmsg_len - sizeof(struct nlmsghdr) <
319 parser->nl_hdr_off)) {
320 /* Doesn't make sense to call nl_alloc_compat_hdr() here. */
321 BIT_ZERO(NL_ATTR_BMASK_SIZE, bm);
322 return;
323 }
324 nl_get_attrs_bmask_raw(
325 (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off),
326 hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off, bm);
327 }
328
329 #endif
330 #endif
331