| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Discover the owner of a connection |
| 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 | /*----- Header files ------------------------------------------------------*/ |
| 28 | |
| 29 | #include "yaid.h" |
| 30 | |
| 31 | /*----- Static variables --------------------------------------------------*/ |
| 32 | |
| 33 | const char *const errtok[] = { |
| 34 | #define DEFTOK(err, tok) tok, |
| 35 | ERROR(DEFTOK) |
| 36 | #undef DEFTOK |
| 37 | }; |
| 38 | |
| 39 | static int parseaddr4(char **pp, union addr *a) |
| 40 | { a->ipv4.s_addr = strtoul(*pp, pp, 16); return (0); } |
| 41 | |
| 42 | static int addreq4(const union addr *a, const union addr *aa) |
| 43 | { return a->ipv4.s_addr == aa->ipv4.s_addr; } |
| 44 | |
| 45 | static int parseaddr6(char **pp, union addr *a) |
| 46 | { |
| 47 | int i, j; |
| 48 | unsigned long y; |
| 49 | char *p = *pp; |
| 50 | unsigned x; |
| 51 | |
| 52 | for (i = 0; i < 4; i++) { |
| 53 | y = 0; |
| 54 | for (j = 0; j < 8; j++) { |
| 55 | if ('0' <= *p && *p <= '9') x = *p - '0'; |
| 56 | else if ('a' <= *p && *p <= 'f') x = *p - 'a'+ 10; |
| 57 | else if ('A' <= *p && *p <= 'F') x = *p - 'A'+ 10; |
| 58 | else return (-1); |
| 59 | y = (y << 4) | x; |
| 60 | p++; |
| 61 | } |
| 62 | a->ipv6.s6_addr32[i] = y; |
| 63 | } |
| 64 | *pp = p; |
| 65 | return (0); |
| 66 | } |
| 67 | |
| 68 | static int addreq6(const union addr *a, const union addr *b) |
| 69 | { return !memcmp(a->ipv6.s6_addr, b->ipv6.s6_addr, 16); } |
| 70 | |
| 71 | static const struct addrfamily { |
| 72 | int af; |
| 73 | const char *procfile; |
| 74 | int (*parseaddr)(char **pp, union addr *a); |
| 75 | int (*addreq)(const union addr *a, const union addr *aa); |
| 76 | } addrfamilytab[] = { |
| 77 | { AF_INET, "/proc/net/tcp", parseaddr4, addreq4 }, |
| 78 | { AF_INET6, "/proc/net/tcp6", parseaddr6, addreq6 }, |
| 79 | { -1 } |
| 80 | }; |
| 81 | |
| 82 | /*----- Main code ---------------------------------------------------------*/ |
| 83 | |
| 84 | static int sockeq(const struct addrfamily *af, |
| 85 | const struct socket *sa, const struct socket *sb) |
| 86 | { return (af->addreq(&sa->addr, &sb->addr) && sa->port == sb->port); } |
| 87 | |
| 88 | int get_default_gw(int af, union addr *a) |
| 89 | { |
| 90 | int fd; |
| 91 | char buf[32768]; |
| 92 | struct nlmsghdr *nlmsg; |
| 93 | struct rtgenmsg *rtgen; |
| 94 | const struct rtattr *rta; |
| 95 | const struct rtmsg *rtm; |
| 96 | ssize_t n, nn; |
| 97 | int rc = 0; |
| 98 | static unsigned long seq = 0x48b4aec4; |
| 99 | |
| 100 | if ((fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0) |
| 101 | die(1, "failed to create netlink socket: %s", strerror(errno)); |
| 102 | |
| 103 | nlmsg = (struct nlmsghdr *)buf; |
| 104 | assert(NLMSG_SPACE(sizeof(*rtgen)) < sizeof(buf)); |
| 105 | nlmsg->nlmsg_len = NLMSG_LENGTH(sizeof(*rtgen)); |
| 106 | nlmsg->nlmsg_type = RTM_GETROUTE; |
| 107 | nlmsg->nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT; |
| 108 | nlmsg->nlmsg_seq = ++seq; |
| 109 | nlmsg->nlmsg_pid = 0; |
| 110 | |
| 111 | rtgen = (struct rtgenmsg *)NLMSG_DATA(nlmsg); |
| 112 | rtgen->rtgen_family = af; |
| 113 | |
| 114 | if (write(fd, nlmsg, nlmsg->nlmsg_len) < 0) |
| 115 | die(1, "failed to send RTM_GETROUTE request: %s", strerror(errno)); |
| 116 | |
| 117 | for (;;) { |
| 118 | if ((n = read(fd, buf, sizeof(buf))) < 0) |
| 119 | die(1, "failed to read RTM_GETROUTE response: %s", strerror(errno)); |
| 120 | nlmsg = (struct nlmsghdr *)buf; |
| 121 | if (nlmsg->nlmsg_seq != seq) continue; |
| 122 | assert(nlmsg->nlmsg_flags & NLM_F_MULTI); |
| 123 | |
| 124 | for (; NLMSG_OK(nlmsg, n); nlmsg = NLMSG_NEXT(nlmsg, n)) { |
| 125 | if (nlmsg->nlmsg_type == NLMSG_DONE) goto done; |
| 126 | if (nlmsg->nlmsg_type != RTM_NEWROUTE) continue; |
| 127 | rtm = (const struct rtmsg *)NLMSG_DATA(nlmsg); |
| 128 | |
| 129 | if (rtm->rtm_family != af || |
| 130 | rtm->rtm_dst_len > 0 || |
| 131 | rtm->rtm_src_len > 0 || |
| 132 | rtm->rtm_type != RTN_UNICAST || |
| 133 | rtm->rtm_scope != RT_SCOPE_UNIVERSE || |
| 134 | rtm->rtm_tos != 0) |
| 135 | continue; |
| 136 | |
| 137 | for (rta = RTM_RTA(rtm), nn = RTM_PAYLOAD(nlmsg); |
| 138 | RTA_OK(rta, nn); rta = RTA_NEXT(rta, nn)) { |
| 139 | if (rta->rta_type == RTA_GATEWAY) { |
| 140 | assert(RTA_PAYLOAD(rta) <= sizeof(*a)); |
| 141 | memcpy(a, RTA_DATA(rta), RTA_PAYLOAD(rta)); |
| 142 | rc = 1; |
| 143 | } |
| 144 | } |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | done: |
| 149 | close(fd); |
| 150 | return (rc); |
| 151 | } |
| 152 | |
| 153 | void identify(struct query *q) |
| 154 | { |
| 155 | const struct addrfamily *af; |
| 156 | FILE *fp = 0; |
| 157 | dstr d = DSTR_INIT; |
| 158 | char *p, *pp; |
| 159 | struct socket s[4]; |
| 160 | int i; |
| 161 | int gwp = 0; |
| 162 | unsigned fl; |
| 163 | #define F_SADDR 1u |
| 164 | #define F_SPORT 2u |
| 165 | #define F_DADDR 4u |
| 166 | #define F_DPORT 8u |
| 167 | #define F_ALL (F_SADDR | F_SPORT | F_DADDR | F_DPORT) |
| 168 | #define F_ESTAB 16u |
| 169 | uid_t uid; |
| 170 | enum { LOC, REM, ST, UID, NFIELD }; |
| 171 | int f, ff[NFIELD]; |
| 172 | |
| 173 | for (af = addrfamilytab; af->af >= 0; af++) |
| 174 | if (af->af == q->af) goto found_af; |
| 175 | logmsg(q, LOG_ERR, "unexpected address family `%d'", q->af); |
| 176 | goto err_unk; |
| 177 | found_af:; |
| 178 | |
| 179 | if (get_default_gw(q->af, &s[0].addr) && |
| 180 | af->addreq(&s[0].addr, &q->s[R].addr)) |
| 181 | gwp = 1; |
| 182 | |
| 183 | if ((fp = fopen(af->procfile, "r")) == 0) { |
| 184 | logmsg(q, LOG_ERR, "failed to open `%s' for reading: %s", |
| 185 | af->procfile, strerror(errno)); |
| 186 | goto err_unk; |
| 187 | } |
| 188 | |
| 189 | #define NEXTFIELD do { \ |
| 190 | for (p = pp; isspace((unsigned char)*p); p++); \ |
| 191 | for (pp = p; *pp && !isspace((unsigned char)*pp); pp++); \ |
| 192 | if (*pp) *pp++ = 0; \ |
| 193 | } while (0) |
| 194 | |
| 195 | if (dstr_putline(&d, fp) == EOF) { |
| 196 | logmsg(q, LOG_ERR, "failed to read header line from `%s': %s", |
| 197 | af->procfile, ferror(fp) ? strerror(errno) : "unexpected EOF"); |
| 198 | goto err_unk; |
| 199 | } |
| 200 | |
| 201 | for (i = 0; i < NFIELD; i++) ff[i] = -1; |
| 202 | pp = d.buf; |
| 203 | for (f = 0;; f++) { |
| 204 | NEXTFIELD; if (!*p) break; |
| 205 | if (strcmp(p, "local_address") == 0) |
| 206 | ff[LOC] = f; |
| 207 | else if (strcmp(p, "rem_address") == 0 || |
| 208 | strcmp(p, "remote_address") == 0) |
| 209 | ff[REM] = f; |
| 210 | else if (strcmp(p, "uid") == 0) |
| 211 | ff[UID] = f; |
| 212 | else if (strcmp(p, "st") == 0) |
| 213 | ff[ST] = f; |
| 214 | else if (strcmp(p, "rx_queue") == 0 || |
| 215 | strcmp(p, "tm->when") == 0) |
| 216 | f--; |
| 217 | } |
| 218 | for (i = 0; i < NFIELD; i++) { |
| 219 | if (ff[i] < 0) { |
| 220 | logmsg(q, LOG_ERR, "failed to find required fields in `%s'", |
| 221 | af->procfile); |
| 222 | goto err_unk; |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | for (;;) { |
| 227 | DRESET(&d); |
| 228 | if (dstr_putline(&d, fp) == EOF) break; |
| 229 | pp = d.buf; |
| 230 | uid = -1; |
| 231 | for (f = 0;; f++) { |
| 232 | NEXTFIELD; if (!*p) break; |
| 233 | if (f == ff[LOC]) { i = L; goto compare; } |
| 234 | else if (f == ff[REM]) { i = R; goto compare; } |
| 235 | else if (f == ff[UID]) uid = atoi(p); |
| 236 | else if (f == ff[ST]) { |
| 237 | if (strtol(p, 0, 16) != 1) goto next_row; |
| 238 | } |
| 239 | continue; |
| 240 | |
| 241 | compare: |
| 242 | if (af->parseaddr(&p, &s[0].addr)) goto next_row; |
| 243 | if (*p != ':') break; p++; |
| 244 | s[0].port = strtoul(p, 0, 16); |
| 245 | if (!sockeq(af, &q->s[i], &s[0]) && |
| 246 | (i != R || !gwp || q->s[R].port != s[0].port)) |
| 247 | goto next_row; |
| 248 | } |
| 249 | if (uid != -1) { |
| 250 | q->resp = R_UID; |
| 251 | q->u.uid = uid; |
| 252 | goto done; |
| 253 | } |
| 254 | next_row:; |
| 255 | } |
| 256 | |
| 257 | if (ferror(fp)) { |
| 258 | logmsg(q, LOG_ERR, "failed to read connection table: %s", |
| 259 | strerror(errno)); |
| 260 | goto err_unk; |
| 261 | } |
| 262 | |
| 263 | if (q->af == AF_INET) { |
| 264 | fclose(fp); |
| 265 | if ((fp = fopen("/proc/net/ip_conntrack", "r")) == 0) { |
| 266 | if (errno == ENOENT) |
| 267 | goto err_nouser; |
| 268 | else { |
| 269 | logmsg(q, LOG_ERR, |
| 270 | "failed to open `/proc/net/ip_conntrack' for reading: %s", |
| 271 | strerror(errno)); |
| 272 | goto err_unk; |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | for (;;) { |
| 277 | DRESET(&d); |
| 278 | if (dstr_putline(&d, fp) == EOF) break; |
| 279 | pp = d.buf; |
| 280 | NEXTFIELD; if (!*p) break; |
| 281 | if (strcmp(p, "tcp") != 0) continue; |
| 282 | i = 0; |
| 283 | fl = 0; |
| 284 | for (;;) { |
| 285 | NEXTFIELD; if (!*p) break; |
| 286 | if (strcmp(p, "ESTABLISHED") == 0) |
| 287 | fl |= F_ESTAB; |
| 288 | else if (strncmp(p, "src=", 4) == 0) { |
| 289 | inet_pton(AF_INET, p + 4, &s[i].addr); |
| 290 | fl |= F_SADDR; |
| 291 | } else if (strncmp(p, "dst=", 4) == 0) { |
| 292 | inet_pton(AF_INET, p + 4, &s[i + 1].addr); |
| 293 | fl |= F_DADDR; |
| 294 | } else if (strncmp(p, "sport=", 6) == 0) { |
| 295 | s[i].port = atoi(p + 6); |
| 296 | fl |= F_SPORT; |
| 297 | } else if (strncmp(p, "dport=", 6) == 0) { |
| 298 | s[i + 1].port = atoi(p + 6); |
| 299 | fl |= F_DPORT; |
| 300 | } |
| 301 | if ((fl & F_ALL) == F_ALL) { |
| 302 | fl &= ~F_ALL; |
| 303 | if (i < 4) i += 2; |
| 304 | else break; |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | #ifdef notdef |
| 309 | { |
| 310 | dstr dd = DSTR_INIT; |
| 311 | dstr_putf(&dd, "%sestab ", (fl & F_ESTAB) ? " " : "!"); |
| 312 | dputsock(&dd, af->af, &s[0]); |
| 313 | dstr_puts(&dd, "<->"); |
| 314 | dputsock(&dd, af->af, &s[1]); |
| 315 | dstr_puts(&dd, " | "); |
| 316 | dputsock(&dd, af->af, &s[2]); |
| 317 | dstr_puts(&dd, "<->"); |
| 318 | dputsock(&dd, af->af, &s[3]); |
| 319 | printf("parsed: %s\n", dd.buf); |
| 320 | dstr_destroy(&dd); |
| 321 | } |
| 322 | #endif |
| 323 | |
| 324 | if (!(fl & F_ESTAB)) continue; |
| 325 | |
| 326 | for (i = 0; i < 4; i++) |
| 327 | if (sockeq(af, &s[i], &q->s[L])) goto found_local; |
| 328 | continue; |
| 329 | putchar('.'); |
| 330 | found_local: |
| 331 | if (!sockeq(af, &s[i^1], &s[i^2]) || |
| 332 | !sockeq(af, &s[i^1], &q->s[R])) |
| 333 | continue; |
| 334 | q->resp = R_NAT; |
| 335 | q->u.nat = s[i^3]; |
| 336 | goto done; |
| 337 | } |
| 338 | |
| 339 | if (ferror(fp)) { |
| 340 | logmsg(q, LOG_ERR, "failed to read `/proc/net/ip_conntrack': %s", |
| 341 | strerror(errno)); |
| 342 | goto err_unk; |
| 343 | } |
| 344 | logmsg(q, LOG_ERR, "connection not found"); |
| 345 | } |
| 346 | |
| 347 | #undef NEXTFIELD |
| 348 | |
| 349 | err_nouser: |
| 350 | q->resp = R_ERROR; |
| 351 | q->u.error = E_NOUSER; |
| 352 | goto done; |
| 353 | err_unk: |
| 354 | q->resp = R_ERROR; |
| 355 | q->u.error = E_UNKNOWN; |
| 356 | done: |
| 357 | dstr_destroy(&d); |
| 358 | } |
| 359 | |
| 360 | /*----- That's all, folks -------------------------------------------------*/ |