1 /* $OpenBSD: ex_init.c,v 1.19 2021/10/24 21:24:17 deraadt Exp $ */ 2 3 /*- 4 * Copyright (c) 1992, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * Copyright (c) 1992, 1993, 1994, 1995, 1996 7 * Keith Bostic. All rights reserved. 8 * 9 * See the LICENSE file for redistribution information. 10 */ 11 12 #include "config.h" 13 14 #include <sys/queue.h> 15 #include <sys/stat.h> 16 17 #include <bitstring.h> 18 #include <errno.h> 19 #include <fcntl.h> 20 #include <limits.h> 21 #include <stdio.h> 22 #include <stdlib.h> 23 #include <string.h> 24 #include <unistd.h> 25 26 #include "../common/common.h" 27 #include "tag.h" 28 #include "pathnames.h" 29 30 enum rc { NOEXIST, NOPERM, RCOK }; 31 static enum rc exrc_isok(SCR *, struct stat *, int *, char *, int, int); 32 33 static int ex_run_file(SCR *, int, char *); 34 35 /* 36 * ex_screen_copy -- 37 * Copy ex screen. 38 * 39 * PUBLIC: int ex_screen_copy(SCR *, SCR *); 40 */ 41 int 42 ex_screen_copy(SCR *orig, SCR *sp) 43 { 44 EX_PRIVATE *oexp, *nexp; 45 46 /* Create the private ex structure. */ 47 CALLOC_RET(orig, nexp, 1, sizeof(EX_PRIVATE)); 48 sp->ex_private = nexp; 49 50 /* Initialize queues. */ 51 TAILQ_INIT(&nexp->tq); 52 TAILQ_INIT(&nexp->tagfq); 53 54 if (orig == NULL) { 55 } else { 56 oexp = EXP(orig); 57 58 if (oexp->lastbcomm != NULL && 59 (nexp->lastbcomm = strdup(oexp->lastbcomm)) == NULL) { 60 msgq(sp, M_SYSERR, NULL); 61 return(1); 62 } 63 if (ex_tag_copy(orig, sp)) 64 return (1); 65 } 66 return (0); 67 } 68 69 /* 70 * ex_screen_end -- 71 * End a vi screen. 72 * 73 * PUBLIC: int ex_screen_end(SCR *); 74 */ 75 int 76 ex_screen_end(SCR *sp) 77 { 78 EX_PRIVATE *exp; 79 int rval; 80 81 if ((exp = EXP(sp)) == NULL) 82 return (0); 83 84 rval = 0; 85 86 /* Close down script connections. */ 87 if (F_ISSET(sp, SC_SCRIPT) && sscr_end(sp)) 88 rval = 1; 89 90 if (argv_free(sp)) 91 rval = 1; 92 93 free(exp->ibp); 94 free(exp->lastbcomm); 95 96 if (ex_tag_free(sp)) 97 rval = 1; 98 99 /* Free private memory. */ 100 free(exp); 101 sp->ex_private = NULL; 102 103 return (rval); 104 } 105 106 /* 107 * ex_optchange -- 108 * Handle change of options for ex. 109 * 110 * PUBLIC: int ex_optchange(SCR *, int, char *, u_long *); 111 */ 112 int 113 ex_optchange(SCR *sp, int offset, char *str, u_long *valp) 114 { 115 switch (offset) { 116 case O_TAGS: 117 return (ex_tagf_alloc(sp, str)); 118 } 119 return (0); 120 } 121 122 /* 123 * ex_exrc -- 124 * Read the EXINIT environment variable and the startup exrc files, 125 * and execute their commands. 126 * 127 * PUBLIC: int ex_exrc(SCR *); 128 */ 129 int 130 ex_exrc(SCR *sp) 131 { 132 struct stat hsb, lsb; 133 char *p, path[PATH_MAX]; 134 int fd; 135 136 /* 137 * Source the system, environment, $HOME and local .exrc values. 138 * Vi historically didn't check $HOME/.exrc if the environment 139 * variable EXINIT was set. This is all done before the file is 140 * read in, because things in the .exrc information can set, for 141 * example, the recovery directory. 142 * 143 * !!! 144 * While nvi can handle any of the options settings of historic vi, 145 * the converse is not true. Since users are going to have to have 146 * files and environmental variables that work with both, we use nvi 147 * versions of both the $HOME and local startup files if they exist, 148 * otherwise the historic ones. 149 * 150 * !!! 151 * For a discussion of permissions and when what .exrc files are 152 * read, see the comment above the exrc_isok() function below. 153 * 154 * !!! 155 * If the user started the historic of vi in $HOME, vi read the user's 156 * .exrc file twice, as $HOME/.exrc and as ./.exrc. We avoid this, as 157 * it's going to make some commands behave oddly, and I can't imagine 158 * anyone depending on it. 159 */ 160 switch (exrc_isok(sp, &hsb, &fd, _PATH_SYSEXRC, 1, 0)) { 161 case NOEXIST: 162 case NOPERM: 163 break; 164 case RCOK: 165 if (ex_run_file(sp, fd, _PATH_SYSEXRC)) 166 return (1); 167 break; 168 } 169 170 /* Run the commands. */ 171 if (EXCMD_RUNNING(sp->gp)) 172 (void)ex_cmd(sp); 173 if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) 174 return (0); 175 176 if ((p = getenv("NEXINIT")) != NULL) { 177 if (ex_run_str(sp, "NEXINIT", p, strlen(p), 1, 0)) 178 return (1); 179 } else if ((p = getenv("EXINIT")) != NULL) { 180 if (ex_run_str(sp, "EXINIT", p, strlen(p), 1, 0)) 181 return (1); 182 } else if ((p = getenv("HOME")) != NULL && *p) { 183 (void)snprintf(path, sizeof(path), "%s/%s", p, _PATH_NEXRC); 184 switch (exrc_isok(sp, &hsb, &fd, path, 0, 1)) { 185 case NOEXIST: 186 (void)snprintf(path, 187 sizeof(path), "%s/%s", p, _PATH_EXRC); 188 if (exrc_isok(sp, &hsb, &fd, path, 0, 1) == RCOK && 189 ex_run_file(sp, fd, path)) 190 return (1); 191 break; 192 case NOPERM: 193 break; 194 case RCOK: 195 if (ex_run_file(sp, fd, path)) 196 return (1); 197 break; 198 } 199 } 200 201 /* Run the commands. */ 202 if (EXCMD_RUNNING(sp->gp)) 203 (void)ex_cmd(sp); 204 if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) 205 return (0); 206 207 /* Previous commands may have set the exrc option. */ 208 if (O_ISSET(sp, O_EXRC)) { 209 switch (exrc_isok(sp, &lsb, &fd, _PATH_NEXRC, 0, 0)) { 210 case NOEXIST: 211 if (exrc_isok(sp, &lsb, &fd, _PATH_EXRC, 0, 0) 212 == RCOK) { 213 if (lsb.st_dev != hsb.st_dev || 214 lsb.st_ino != hsb.st_ino) { 215 if (ex_run_file(sp, fd, _PATH_EXRC)) 216 return (1); 217 } else 218 close(fd); 219 } 220 break; 221 case NOPERM: 222 break; 223 case RCOK: 224 if (lsb.st_dev != hsb.st_dev || 225 lsb.st_ino != hsb.st_ino) { 226 if (ex_run_file(sp, fd, _PATH_NEXRC)) 227 return (1); 228 } else 229 close(fd); 230 break; 231 } 232 /* Run the commands. */ 233 if (EXCMD_RUNNING(sp->gp)) 234 (void)ex_cmd(sp); 235 if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) 236 return (0); 237 } 238 239 return (0); 240 } 241 242 /* 243 * ex_run_file -- 244 * Set up a file of ex commands to run. 245 */ 246 static int 247 ex_run_file(SCR *sp, int fd, char *name) 248 { 249 ARGS *ap[2], a; 250 EXCMD cmd; 251 252 ex_cinit(&cmd, C_SOURCE, 0, OOBLNO, OOBLNO, 0, ap); 253 ex_cadd(&cmd, &a, name, strlen(name)); 254 return (ex_sourcefd(sp, &cmd, fd)); 255 } 256 257 /* 258 * ex_run_str -- 259 * Set up a string of ex commands to run. 260 * 261 * PUBLIC: int ex_run_str(SCR *, char *, char *, size_t, int, int); 262 */ 263 int 264 ex_run_str(SCR *sp, char *name, char *str, size_t len, int ex_flags, 265 int nocopy) 266 { 267 GS *gp; 268 EXCMD *ecp; 269 270 gp = sp->gp; 271 if (EXCMD_RUNNING(gp)) { 272 CALLOC_RET(sp, ecp, 1, sizeof(EXCMD)); 273 LIST_INSERT_HEAD(&gp->ecq, ecp, q); 274 } else 275 ecp = &gp->excmd; 276 277 F_INIT(ecp, 278 ex_flags ? E_BLIGNORE | E_NOAUTO | E_NOPRDEF | E_VLITONLY : 0); 279 280 if (nocopy) 281 ecp->cp = str; 282 else 283 if ((ecp->cp = v_strdup(sp, str, len)) == NULL) 284 return (1); 285 ecp->clen = len; 286 287 if (name == NULL) 288 ecp->if_name = NULL; 289 else { 290 if ((ecp->if_name = v_strdup(sp, name, strlen(name))) == NULL) 291 return (1); 292 ecp->if_lno = 1; 293 F_SET(ecp, E_NAMEDISCARD); 294 } 295 296 return (0); 297 } 298 299 /* 300 * exrc_isok -- 301 * Open and check a .exrc file for source-ability. 302 * 303 * !!! 304 * Historically, vi read the $HOME and local .exrc files if they were owned 305 * by the user's real ID, or the "sourceany" option was set, regardless of 306 * any other considerations. We no longer support the sourceany option as 307 * it's a security problem of mammoth proportions. We require the system 308 * .exrc file to be owned by root, the $HOME .exrc file to be owned by the 309 * user's effective ID (or that the user's effective ID be root) and the 310 * local .exrc files to be owned by the user's effective ID. In all cases, 311 * the file cannot be writeable by anyone other than its owner. 312 * 313 * In O'Reilly ("Learning the VI Editor", Fifth Ed., May 1992, page 106), 314 * it notes that System V release 3.2 and later has an option "[no]exrc". 315 * The behavior is that local .exrc files are read only if the exrc option 316 * is set. The default for the exrc option was off, so, by default, local 317 * .exrc files were not read. The problem this was intended to solve was 318 * that System V permitted users to give away files, so there's no possible 319 * ownership or writeability test to ensure that the file is safe. 320 * 321 * POSIX 1003.2-1992 standardized exrc as an option. It required the exrc 322 * option to be off by default, thus local .exrc files are not to be read 323 * by default. The Rationale noted (incorrectly) that this was a change 324 * to historic practice, but correctly noted that a default of off improves 325 * system security. POSIX also required that vi check the effective user 326 * ID instead of the real user ID, which is why we've switched from historic 327 * practice. 328 * 329 * We initialize the exrc variable to off. If it's turned on by the system 330 * or $HOME .exrc files, and the local .exrc file passes the ownership and 331 * writeability tests, then we read it. This breaks historic 4BSD practice, 332 * but it gives us a measure of security on systems where users can give away 333 * files. 334 */ 335 static enum rc 336 exrc_isok(SCR *sp, struct stat *sbp, int *fdp, char *path, int rootown, 337 int rootid) 338 { 339 enum { ROOTOWN, OWN, WRITER } etype; 340 uid_t euid; 341 int nf1, nf2; 342 char *a, *b, buf[PATH_MAX]; 343 344 if ((*fdp = open(path, O_RDONLY)) < 0) { 345 if (errno == ENOENT) 346 /* This is the only case where ex_exrc() 347 * should silently try the next file, for 348 * example .exrc after .nexrc. 349 */ 350 return (NOEXIST); 351 352 msgq_str(sp, M_SYSERR, path, "%s"); 353 return (NOPERM); 354 } 355 356 if (fstat(*fdp, sbp)) { 357 msgq_str(sp, M_SYSERR, path, "%s"); 358 close(*fdp); 359 return (NOPERM); 360 } 361 362 /* Check ownership permissions. */ 363 euid = geteuid(); 364 if (!(rootown && sbp->st_uid == 0) && 365 !(rootid && euid == 0) && sbp->st_uid != euid) { 366 etype = rootown ? ROOTOWN : OWN; 367 goto denied; 368 } 369 370 /* Check writeability. */ 371 if (sbp->st_mode & (S_IWGRP | S_IWOTH)) { 372 etype = WRITER; 373 goto denied; 374 } 375 return (RCOK); 376 377 denied: a = msg_print(sp, path, &nf1); 378 if (strchr(path, '/') == NULL && getcwd(buf, sizeof(buf)) != NULL) { 379 b = msg_print(sp, buf, &nf2); 380 switch (etype) { 381 case ROOTOWN: 382 msgq(sp, M_ERR, 383 "%s/%s: not sourced: not owned by you or root", 384 b, a); 385 break; 386 case OWN: 387 msgq(sp, M_ERR, 388 "%s/%s: not sourced: not owned by you", b, a); 389 break; 390 case WRITER: 391 msgq(sp, M_ERR, 392 "%s/%s: not sourced: writable by a user other than the owner", b, a); 393 break; 394 } 395 if (nf2) 396 FREE_SPACE(sp, b, 0); 397 } else 398 switch (etype) { 399 case ROOTOWN: 400 msgq(sp, M_ERR, 401 "%s: not sourced: not owned by you or root", a); 402 break; 403 case OWN: 404 msgq(sp, M_ERR, 405 "%s: not sourced: not owned by you", a); 406 break; 407 case WRITER: 408 msgq(sp, M_ERR, 409 "%s: not sourced: writable by a user other than the owner", a); 410 break; 411 } 412 413 if (nf1) 414 FREE_SPACE(sp, a, 0); 415 close(*fdp); 416 return (NOPERM); 417 } 418