| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Common definitions for YAID |
| 4 | * |
| 5 | * (c) 2012 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Yet Another Ident Daemon (YAID). |
| 11 | * |
| 12 | * YAID is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or |
| 15 | * (at your option) any later version. |
| 16 | * |
| 17 | * YAID is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with YAID; if not, write to the Free Software Foundation, |
| 24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | #ifndef YAID_H |
| 28 | #define YAID_H |
| 29 | |
| 30 | #ifdef __cplusplus |
| 31 | extern "C" { |
| 32 | #endif |
| 33 | |
| 34 | /*----- Header files ------------------------------------------------------*/ |
| 35 | |
| 36 | #include "config.h" |
| 37 | |
| 38 | #include <assert.h> |
| 39 | #include <ctype.h> |
| 40 | #include <errno.h> |
| 41 | #include <limits.h> |
| 42 | #include <stdarg.h> |
| 43 | #include <stdio.h> |
| 44 | #include <string.h> |
| 45 | #include <string.h> |
| 46 | #include <time.h> |
| 47 | |
| 48 | #include <sys/types.h> |
| 49 | #include <sys/time.h> |
| 50 | #include <unistd.h> |
| 51 | #include <fcntl.h> |
| 52 | |
| 53 | #include <grp.h> |
| 54 | #include <pwd.h> |
| 55 | |
| 56 | #include <sys/socket.h> |
| 57 | #include <netinet/in.h> |
| 58 | #include <arpa/inet.h> |
| 59 | #include <netdb.h> |
| 60 | |
| 61 | #include <syslog.h> |
| 62 | |
| 63 | #include <mLib/bits.h> |
| 64 | #include <mLib/conn.h> |
| 65 | #include <mLib/daemonize.h> |
| 66 | #include <mLib/darray.h> |
| 67 | #include <mLib/dstr.h> |
| 68 | #include <mLib/fdflags.h> |
| 69 | #include <mLib/fwatch.h> |
| 70 | #include <mLib/mdwopt.h> |
| 71 | #include <mLib/quis.h> |
| 72 | #include <mLib/report.h> |
| 73 | #include <mLib/sel.h> |
| 74 | #include <mLib/selbuf.h> |
| 75 | #include <mLib/sig.h> |
| 76 | |
| 77 | /*----- Address family handling -------------------------------------------*/ |
| 78 | |
| 79 | /* The maximum length of an address formatted as a text string, including the |
| 80 | * terminating null byte. |
| 81 | */ |
| 82 | #define ADDRLEN 64 |
| 83 | |
| 84 | /* A list of address types. */ |
| 85 | #define ADDRTYPES(_) \ |
| 86 | _(ipv4, IPV4) \ |
| 87 | _(ipv6, IPV6) |
| 88 | |
| 89 | /* Address types for the various families, in the form acceptable to |
| 90 | * inet_ntop(3) and inet_pton(3). */ |
| 91 | #define TYPE_IPV4 struct in_addr |
| 92 | #define TYPE_IPV6 struct in6_addr |
| 93 | |
| 94 | /* A union of address types. */ |
| 95 | union addr { |
| 96 | #define UMEMB(ty, TY) TYPE_##TY ty; |
| 97 | ADDRTYPES(UMEMB) |
| 98 | #undef UMEMB |
| 99 | }; |
| 100 | |
| 101 | /* A socket holds an address and a port number. */ |
| 102 | struct socket { |
| 103 | union addr addr; /* The address */ |
| 104 | unsigned port; /* The port, in /host/ byte order */ |
| 105 | }; |
| 106 | |
| 107 | /* An address pattern consists of an address and a prefix length: the |
| 108 | * pattern matches an address if they agree in the first LEN bits. |
| 109 | */ |
| 110 | struct addrpat { |
| 111 | union addr addr; /* The base address */ |
| 112 | unsigned len; /* The prefix length */ |
| 113 | }; |
| 114 | |
| 115 | /* A port pattern matches a port if the port is within the stated (inclusive) |
| 116 | * bounds. |
| 117 | */ |
| 118 | struct portpat { |
| 119 | unsigned lo, hi; |
| 120 | }; |
| 121 | |
| 122 | /* A socket pattern consists simply of an address pattern and a port pattern: |
| 123 | * it matches a socket componentwise. |
| 124 | */ |
| 125 | struct sockpat { |
| 126 | struct addrpat addr; |
| 127 | struct portpat port; |
| 128 | }; |
| 129 | |
| 130 | /* The table of address-type operations. Each address family has one of |
| 131 | * these, so that most of the program doesn't need to worry about these |
| 132 | * details. |
| 133 | */ |
| 134 | struct addrops { |
| 135 | int af; /* The AF_* constant */ |
| 136 | const char *name; /* Name of the protocol, for logs */ |
| 137 | unsigned len; /* Length of an address, in bits */ |
| 138 | const union addr *any; /* A wildcard address */ |
| 139 | const struct addrops_sys *sys; /* Pointer to system-specific ops */ |
| 140 | |
| 141 | int (*addreq)(const union addr *, const union addr *); |
| 142 | /* Return nonzero if the two addresses are equal. */ |
| 143 | |
| 144 | int (*match_addrpat)(const struct addrpat *, const union addr *); |
| 145 | /* Return nonzero if the pattern matches the address. */ |
| 146 | |
| 147 | void (*socket_to_sockaddr)(const struct socket *s, void *, size_t *); |
| 148 | /* Convert a socket structure to a `struct sockaddr', and return the |
| 149 | * size of the latter. |
| 150 | */ |
| 151 | |
| 152 | void (*sockaddr_to_addr)(const void *, union addr *); |
| 153 | /* Extract the address from a `struct sockaddr'. */ |
| 154 | |
| 155 | int (*init_listen_socket)(int); |
| 156 | /* Perform any necessary extra operations on a socket which is going |
| 157 | * to be used to listen for incoming connections. |
| 158 | */ |
| 159 | }; |
| 160 | |
| 161 | /* A handy constant for each address family. These are more useful than the |
| 162 | * AF_* constants in that they form a dense sequence. |
| 163 | */ |
| 164 | enum { |
| 165 | #define DEFADDR(ty, TY) ADDR_##TY, |
| 166 | ADDRTYPES(DEFADDR) |
| 167 | #undef DEFADDR |
| 168 | ADDR_LIMIT |
| 169 | }; |
| 170 | |
| 171 | /* The table of address operations, indexed by the ADDR_* constants defined |
| 172 | * just above. |
| 173 | */ |
| 174 | extern const struct addrops addroptab[]; |
| 175 | |
| 176 | /* System-specific operations, provided by the system-specific code for its |
| 177 | * own purposes. |
| 178 | */ |
| 179 | #define OPS_SYS(ty, TY) \ |
| 180 | extern const struct addrops_sys addrops_sys_##ty; |
| 181 | ADDRTYPES(OPS_SYS) |
| 182 | #undef OPS_SYS |
| 183 | |
| 184 | /* Answer whether the sockets SA and SB are equal. */ |
| 185 | extern int sockeq(const struct addrops */*ao*/, |
| 186 | const struct socket */*sa*/, const struct socket */*sb*/); |
| 187 | |
| 188 | /* Write a textual description of S to the string D. */ |
| 189 | extern void dputsock(dstr */*d*/, const struct addrops */*ao*/, |
| 190 | const struct socket */*s*/); |
| 191 | |
| 192 | /*----- Queries and responses ---------------------------------------------*/ |
| 193 | |
| 194 | /* Constants for describing the `L'ocal and `R'emote ends of a connection. */ |
| 195 | enum { L, R, NDIR }; |
| 196 | |
| 197 | /* Response types, and the data needed to represent any associated data. A |
| 198 | * U_(MEMB, TYPE) constructs a union member; an N_ means no associated data. |
| 199 | */ |
| 200 | #define RESPONSE(_) \ |
| 201 | _(ERROR, U_(error, unsigned)) \ |
| 202 | _(UID, U_(uid, uid_t)) \ |
| 203 | _(NAT, U_(nat, struct socket)) |
| 204 | |
| 205 | enum { |
| 206 | #define DEFENUM(what, branch) R_##what, |
| 207 | RESPONSE(DEFENUM) |
| 208 | #undef DEFENUM |
| 209 | R_LIMIT |
| 210 | }; |
| 211 | |
| 212 | /* Protocol error tokens. */ |
| 213 | #define ERROR(_) \ |
| 214 | _(INVPORT, "INVALID-PORT") \ |
| 215 | _(NOUSER, "NO-USER") \ |
| 216 | _(HIDDEN, "HIDDEN-USER") \ |
| 217 | _(UNKNOWN, "UNKNOWN-ERROR") |
| 218 | |
| 219 | enum { |
| 220 | #define DEFENUM(err, tok) E_##err, |
| 221 | ERROR(DEFENUM) |
| 222 | #undef DEFENUM |
| 223 | E_LIMIT |
| 224 | }; |
| 225 | |
| 226 | extern const char *const errtok[]; |
| 227 | |
| 228 | /* The query structure keeps together the parameters to the client's query |
| 229 | * and our response to it. |
| 230 | */ |
| 231 | struct query { |
| 232 | const struct addrops *ao; /* Address family operations */ |
| 233 | struct socket s[NDIR]; /* The local and remote ends */ |
| 234 | unsigned resp; /* Our response type */ |
| 235 | union { /* A union of response data */ |
| 236 | #define DEFBRANCH(WHAT, branch) branch |
| 237 | #define U_(memb, ty) ty memb; |
| 238 | #define N_ |
| 239 | RESPONSE(DEFBRANCH) |
| 240 | #undef U_ |
| 241 | #undef N_ |
| 242 | #undef DEFBRANCH |
| 243 | } u; |
| 244 | } query; |
| 245 | |
| 246 | /*----- Common utility functions ------------------------------------------*/ |
| 247 | |
| 248 | /* Format and log MSG somewhere sensible, at the syslog(3) priority PRIO. |
| 249 | * Prefix it with a description of the query Q, if non-null. |
| 250 | */ |
| 251 | extern void logmsg(const struct query */*q*/, |
| 252 | int /*prio*/, const char */*msg*/, ...); |
| 253 | |
| 254 | /*----- System-specific connection identification code --------------------*/ |
| 255 | |
| 256 | /* Find out who is responsible for the connection described in the query Q. |
| 257 | * Write the answer to Q. Errors are logged and reported via the query |
| 258 | * structure. |
| 259 | */ |
| 260 | extern void identify(struct query */*q*/); |
| 261 | |
| 262 | /* Initialize the system-specific code. */ |
| 263 | extern void init_sys(void); |
| 264 | |
| 265 | /*----- Policy management -------------------------------------------------*/ |
| 266 | |
| 267 | /* The possible policy actions and their names. */ |
| 268 | #define ACTIONS(_) \ |
| 269 | _(USER, "user") \ |
| 270 | _(TOKEN, "token") \ |
| 271 | _(NAME, "name") \ |
| 272 | _(DENY, "deny") \ |
| 273 | _(HIDE, "hide") \ |
| 274 | _(LIE, "lie") |
| 275 | |
| 276 | enum { |
| 277 | #define DEFENUM(tag, word) A_##tag, |
| 278 | ACTIONS(DEFENUM) |
| 279 | #undef DEFENUM |
| 280 | A_LIMIT |
| 281 | }; |
| 282 | |
| 283 | /* A policy action. */ |
| 284 | struct action { |
| 285 | unsigned act; |
| 286 | union { |
| 287 | unsigned user; /* Bitmask of permitted actions */ |
| 288 | char *lie; /* The user name to impersonate */ |
| 289 | } u; |
| 290 | }; |
| 291 | |
| 292 | /* A user pattern matches a user if the uid is within the given bounds. */ |
| 293 | struct userpat { |
| 294 | unsigned lo, hi; |
| 295 | }; |
| 296 | |
| 297 | /* A policy rule: if the query matches the pattern, then perform the |
| 298 | * action. |
| 299 | */ |
| 300 | struct policy { |
| 301 | const struct addrops *ao; |
| 302 | struct sockpat sp[NDIR]; |
| 303 | struct userpat up; |
| 304 | struct action act; |
| 305 | }; |
| 306 | #define POLICY_INIT(a) { .act.act = a } |
| 307 | DA_DECL(policy_v, struct policy); |
| 308 | |
| 309 | /* Initialize a policy structure. In this state, it doesn't actually have |
| 310 | * any resources allocated (so can be simply discarded) but it's safe to free |
| 311 | * (using `free_policy'). |
| 312 | */ |
| 313 | extern void init_policy(struct policy */*p*/); |
| 314 | |
| 315 | /* Free a policy structure, resetting it to its freshly-initialized state. |
| 316 | * This function is idempotent. |
| 317 | */ |
| 318 | extern void free_policy(struct policy */*p*/); |
| 319 | |
| 320 | /* Print a policy rule to standard output. */ |
| 321 | extern void print_policy(const struct policy */*p*/); |
| 322 | |
| 323 | /* Return true if the query matches the patterns in the policy rule. */ |
| 324 | extern int match_policy(const struct policy */*p*/, |
| 325 | const struct query */*q*/); |
| 326 | |
| 327 | /*----- Parsing policy files ----------------------------------------------*/ |
| 328 | |
| 329 | /* Possible results from a parse. */ |
| 330 | enum { |
| 331 | T_OK, /* Successful: results returned */ |
| 332 | T_EOL, /* End-of-line found immediately */ |
| 333 | T_ERROR, /* Some kind of error occurred */ |
| 334 | T_EOF /* End-of-file found immediately */ |
| 335 | }; |
| 336 | |
| 337 | /* A context for parsing a policy file. */ |
| 338 | struct policy_file { |
| 339 | FILE *fp; /* The file to read from */ |
| 340 | const struct query *q; /* A query to use for logging */ |
| 341 | const char *name; /* The name of the file */ |
| 342 | const char *what; /* A description of the file */ |
| 343 | int err; /* Have there been any errors? */ |
| 344 | int lno; /* The current line number */ |
| 345 | struct policy p; /* Parsed policy rule goes here */ |
| 346 | }; |
| 347 | |
| 348 | /* Open a policy file by NAME. The description WHAT and query Q are used for |
| 349 | * formatting error messages for the log. |
| 350 | */ |
| 351 | extern int open_policy_file(struct policy_file */*pf*/, const char */*name*/, |
| 352 | const char */*what*/, const struct query */*q*/, |
| 353 | unsigned /*f*/); |
| 354 | #define OPF_NOENTOK 1u /* Don't complain if file missing */ |
| 355 | |
| 356 | /* Read a policy rule from the file, storing it in PF->p. Return one of the |
| 357 | * T_* codes. |
| 358 | */ |
| 359 | extern int read_policy_file(struct policy_file */*pf*/); |
| 360 | |
| 361 | /* Close a policy file. It doesn't matter whether the file was completely |
| 362 | * read. |
| 363 | */ |
| 364 | extern void close_policy_file(struct policy_file */*pf*/); |
| 365 | |
| 366 | /* Load a policy file, writing a vector of records into PV. If the policy |
| 367 | * file has errors, then leave PV unchanged and return nonzero. |
| 368 | */ |
| 369 | extern int load_policy_file(const char */*file*/, policy_v */*pv*/); |
| 370 | |
| 371 | /*----- That's all, folks -------------------------------------------------*/ |
| 372 | |
| 373 | #ifdef __cplusplus |
| 374 | } |
| 375 | #endif |
| 376 | |
| 377 | #endif |