contrib/nvi/ex/ex_init.c

   1 /*-
   2  * Copyright (c) 1992, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 1992, 1993, 1994, 1995, 1996
   5  *      Keith Bostic.  All rights reserved.
   6  *
   7  * See the LICENSE file for redistribution information.
   8  */
   9
  10 #include "config.h"
  11
  12 #ifndef lint
  13 static const char sccsid[] = "@(#)ex_init.c     10.26 (Berkeley) 8/12/96";
  14 #endif /* not lint */
  15
  16 #include <sys/param.h>
  17 #include <sys/types.h>          /* XXX: param.h may not have included types.h */
  18 #include <sys/queue.h>
  19 #include <sys/stat.h>
  20
  21 #include <bitstring.h>
  22 #include <fcntl.h>
  23 #include <limits.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28
  29 #include "../common/common.h"
  30 #include "tag.h"
  31 #include "pathnames.h"
  32
  33 enum rc { NOEXIST, NOPERM, RCOK };
  34 static enum rc  exrc_isok __P((SCR *, struct stat *, char *, int, int));
  35
  36 static int ex_run_file __P((SCR *, char *));
  37
  38 /*
  39  * ex_screen_copy --
  40  *      Copy ex screen.
  41  *
  42  * PUBLIC: int ex_screen_copy __P((SCR *, SCR *));
  43  */
  44 int
  45 ex_screen_copy(orig, sp)
  46         SCR *orig, *sp;
  47 {
  48         EX_PRIVATE *oexp, *nexp;
  49
  50         /* Create the private ex structure. */
  51         CALLOC_RET(orig, nexp, EX_PRIVATE *, 1, sizeof(EX_PRIVATE));
  52         sp->ex_private = nexp;
  53
  54         /* Initialize queues. */
  55         CIRCLEQ_INIT(&nexp->tq);
  56         TAILQ_INIT(&nexp->tagfq);
  57         LIST_INIT(&nexp->cscq);
  58
  59         if (orig == NULL) {
  60         } else {
  61                 oexp = EXP(orig);
  62
  63                 if (oexp->lastbcomm != NULL &&
  64                     (nexp->lastbcomm = strdup(oexp->lastbcomm)) == NULL) {
  65                         msgq(sp, M_SYSERR, NULL);
  66                         return(1);
  67                 }
  68                 if (ex_tag_copy(orig, sp))
  69                         return (1);
  70         }
  71         return (0);
  72 }
  73
  74 /*
  75  * ex_screen_end --
  76  *      End a vi screen.
  77  *
  78  * PUBLIC: int ex_screen_end __P((SCR *));
  79  */
  80 int
  81 ex_screen_end(sp)
  82         SCR *sp;
  83 {
  84         EX_PRIVATE *exp;
  85         int rval;
  86
  87         if ((exp = EXP(sp)) == NULL)
  88                 return (0);
  89
  90         rval = 0;
  91
  92         /* Close down script connections. */
  93         if (F_ISSET(sp, SC_SCRIPT) && sscr_end(sp))
  94                 rval = 1;
  95
  96         if (argv_free(sp))
  97                 rval = 1;
  98
  99         if (exp->ibp != NULL)
 100                 free(exp->ibp);
 101
 102         if (exp->lastbcomm != NULL)
 103                 free(exp->lastbcomm);
 104
 105         if (ex_tag_free(sp))
 106                 rval = 1;
 107
 108         /* Free private memory. */
 109         free(exp);
 110         sp->ex_private = NULL;
 111
 112         return (rval);
 113 }
 114
 115 /*
 116  * ex_optchange --
 117  *      Handle change of options for ex.
 118  *
 119  * PUBLIC: int ex_optchange __P((SCR *, int, char *, u_long *));
 120  */
 121 int
 122 ex_optchange(sp, offset, str, valp)
 123         SCR *sp;
 124         int offset;
 125         char *str;
 126         u_long *valp;
 127 {
 128         switch (offset) {
 129         case O_TAGS:
 130                 return (ex_tagf_alloc(sp, str));
 131         }
 132         return (0);
 133 }
 134
 135 /*
 136  * ex_exrc --
 137  *      Read the EXINIT environment variable and the startup exrc files,
 138  *      and execute their commands.
 139  *
 140  * PUBLIC: int ex_exrc __P((SCR *));
 141  */
 142 int
 143 ex_exrc(sp)
 144         SCR *sp;
 145 {
 146         struct stat hsb, lsb;
 147         char *p, path[MAXPATHLEN];
 148
 149         /*
 150          * Source the system, environment, $HOME and local .exrc values.
 151          * Vi historically didn't check $HOME/.exrc if the environment
 152          * variable EXINIT was set.  This is all done before the file is
 153          * read in, because things in the .exrc information can set, for
 154          * example, the recovery directory.
 155          *
 156          * !!!
 157          * While nvi can handle any of the options settings of historic vi,
 158          * the converse is not true.  Since users are going to have to have
 159          * files and environmental variables that work with both, we use nvi
 160          * versions of both the $HOME and local startup files if they exist,
 161          * otherwise the historic ones.
 162          *
 163          * !!!
 164          * For a discussion of permissions and when what .exrc files are
 165          * read, see the comment above the exrc_isok() function below.
 166          *
 167          * !!!
 168          * If the user started the historic of vi in $HOME, vi read the user's
 169          * .exrc file twice, as $HOME/.exrc and as ./.exrc.  We avoid this, as
 170          * it's going to make some commands behave oddly, and I can't imagine
 171          * anyone depending on it.
 172          */
 173         switch (exrc_isok(sp, &hsb, _PATH_SYSEXRC, 1, 0)) {
 174         case NOEXIST:
 175         case NOPERM:
 176                 break;
 177         case RCOK:
 178                 if (ex_run_file(sp, _PATH_SYSEXRC))
 179                         return (1);
 180                 break;
 181         }
 182
 183         /* Run the commands. */
 184         if (EXCMD_RUNNING(sp->gp))
 185                 (void)ex_cmd(sp);
 186         if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE))
 187                 return (0);
 188
 189         if ((p = getenv("NEXINIT")) != NULL) {
 190                 if (ex_run_str(sp, "NEXINIT", p, strlen(p), 1, 0))
 191                         return (1);
 192         } else if ((p = getenv("EXINIT")) != NULL) {
 193                 if (ex_run_str(sp, "EXINIT", p, strlen(p), 1, 0))
 194                         return (1);
 195         } else if ((p = getenv("HOME")) != NULL && *p) {
 196                 (void)snprintf(path, sizeof(path), "%s/%s", p, _PATH_NEXRC);
 197                 switch (exrc_isok(sp, &hsb, path, 0, 1)) {
 198                 case NOEXIST:
 199                         (void)snprintf(path,
 200                             sizeof(path), "%s/%s", p, _PATH_EXRC);
 201                         if (exrc_isok(sp,
 202                             &hsb, path, 0, 1) == RCOK && ex_run_file(sp, path))
 203                                 return (1);
 204                         break;
 205                 case NOPERM:
 206                         break;
 207                 case RCOK:
 208                         if (ex_run_file(sp, path))
 209                                 return (1);
 210                         break;
 211                 }
 212         }
 213
 214         /* Run the commands. */
 215         if (EXCMD_RUNNING(sp->gp))
 216                 (void)ex_cmd(sp);
 217         if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE))
 218                 return (0);
 219
 220         /* Previous commands may have set the exrc option. */
 221         if (O_ISSET(sp, O_EXRC)) {
 222                 switch (exrc_isok(sp, &lsb, _PATH_NEXRC, 0, 0)) {
 223                 case NOEXIST:
 224                         if (exrc_isok(sp, &lsb, _PATH_EXRC, 0, 0) == RCOK &&
 225                             (lsb.st_dev != hsb.st_dev ||
 226                             lsb.st_ino != hsb.st_ino) &&
 227                             ex_run_file(sp, _PATH_EXRC))
 228                                 return (1);
 229                         break;
 230                 case NOPERM:
 231                         break;
 232                 case RCOK:
 233                         if ((lsb.st_dev != hsb.st_dev ||
 234                             lsb.st_ino != hsb.st_ino) &&
 235                             ex_run_file(sp, _PATH_NEXRC))
 236                                 return (1);
 237                         break;
 238                 }
 239                 /* Run the commands. */
 240                 if (EXCMD_RUNNING(sp->gp))
 241                         (void)ex_cmd(sp);
 242                 if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE))
 243                         return (0);
 244         }
 245
 246         return (0);
 247 }
 248
 249 /*
 250  * ex_run_file --
 251  *      Set up a file of ex commands to run.
 252  */
 253 static int
 254 ex_run_file(sp, name)
 255         SCR *sp;
 256         char *name;
 257 {
 258         ARGS *ap[2], a;
 259         EXCMD cmd;
 260
 261         ex_cinit(&cmd, C_SOURCE, 0, OOBLNO, OOBLNO, 0, ap);
 262         ex_cadd(&cmd, &a, name, strlen(name));
 263         return (ex_source(sp, &cmd));
 264 }
 265
 266 /*
 267  * ex_run_str --
 268  *      Set up a string of ex commands to run.
 269  *
 270  * PUBLIC: int ex_run_str __P((SCR *, char *, char *, size_t, int, int));
 271  */
 272 int
 273 ex_run_str(sp, name, str, len, ex_flags, nocopy)
 274         SCR *sp;
 275         char *name, *str;
 276         size_t len;
 277         int ex_flags, nocopy;
 278 {
 279         GS *gp;
 280         EXCMD *ecp;
 281
 282         gp = sp->gp;
 283         if (EXCMD_RUNNING(gp)) {
 284                 CALLOC_RET(sp, ecp, EXCMD *, 1, sizeof(EXCMD));
 285                 LIST_INSERT_HEAD(&gp->ecq, ecp, q);
 286         } else
 287                 ecp = &gp->excmd;
 288
 289         F_INIT(ecp,
 290             ex_flags ? E_BLIGNORE | E_NOAUTO | E_NOPRDEF | E_VLITONLY : 0);
 291
 292         if (nocopy)
 293                 ecp->cp = str;
 294         else
 295                 if ((ecp->cp = v_strdup(sp, str, len)) == NULL)
 296                         return (1);
 297         ecp->clen = len;
 298
 299         if (name == NULL)
 300                 ecp->if_name = NULL;
 301         else {
 302                 if ((ecp->if_name = v_strdup(sp, name, strlen(name))) == NULL)
 303                         return (1);
 304                 ecp->if_lno = 1;
 305                 F_SET(ecp, E_NAMEDISCARD);
 306         }
 307
 308         return (0);
 309 }
 310
 311 /*
 312  * exrc_isok --
 313  *      Check a .exrc file for source-ability.
 314  *
 315  * !!!
 316  * Historically, vi read the $HOME and local .exrc files if they were owned
 317  * by the user's real ID, or the "sourceany" option was set, regardless of
 318  * any other considerations.  We no longer support the sourceany option as
 319  * it's a security problem of mammoth proportions.  We require the system
 320  * .exrc file to be owned by root, the $HOME .exrc file to be owned by the
 321  * user's effective ID (or that the user's effective ID be root) and the
 322  * local .exrc files to be owned by the user's effective ID.  In all cases,
 323  * the file cannot be writeable by anyone other than its owner.
 324  *
 325  * In O'Reilly ("Learning the VI Editor", Fifth Ed., May 1992, page 106),
 326  * it notes that System V release 3.2 and later has an option "[no]exrc".
 327  * The behavior is that local .exrc files are read only if the exrc option
 328  * is set.  The default for the exrc option was off, so, by default, local
 329  * .exrc files were not read.  The problem this was intended to solve was
 330  * that System V permitted users to give away files, so there's no possible
 331  * ownership or writeability test to ensure that the file is safe.
 332  *
 333  * POSIX 1003.2-1992 standardized exrc as an option.  It required the exrc
 334  * option to be off by default, thus local .exrc files are not to be read
 335  * by default.  The Rationale noted (incorrectly) that this was a change
 336  * to historic practice, but correctly noted that a default of off improves
 337  * system security.  POSIX also required that vi check the effective user
 338  * ID instead of the real user ID, which is why we've switched from historic
 339  * practice.
 340  *
 341  * We initialize the exrc variable to off.  If it's turned on by the system
 342  * or $HOME .exrc files, and the local .exrc file passes the ownership and
 343  * writeability tests, then we read it.  This breaks historic 4BSD practice,
 344  * but it gives us a measure of security on systems where users can give away
 345  * files.
 346  */
 347 static enum rc
 348 exrc_isok(sp, sbp, path, rootown, rootid)
 349         SCR *sp;
 350         struct stat *sbp;
 351         char *path;
 352         int rootown, rootid;
 353 {
 354         enum { ROOTOWN, OWN, WRITER } etype;
 355         uid_t euid;
 356         int nf1, nf2;
 357         char *a, *b, buf[MAXPATHLEN];
 358
 359         /* Check for the file's existence. */
 360         if (stat(path, sbp))
 361                 return (NOEXIST);
 362
 363         /* Check ownership permissions. */
 364         euid = geteuid();
 365         if (!(rootown && sbp->st_uid == 0) &&
 366             !(rootid && euid == 0) && sbp->st_uid != euid) {
 367                 etype = rootown ? ROOTOWN : OWN;
 368                 goto denied;
 369         }
 370
 371         /* Check writeability. */
 372         if (sbp->st_mode & (S_IWGRP | S_IWOTH)) {
 373                 etype = WRITER;
 374                 goto denied;
 375         }
 376         return (RCOK);
 377
 378 denied: a = msg_print(sp, path, &nf1);
 379         if (strchr(path, '/') == NULL && getcwd(buf, sizeof(buf)) != NULL) {
 380                 b = msg_print(sp, buf, &nf2);
 381                 switch (etype) {
 382                 case ROOTOWN:
 383                         msgq(sp, M_ERR,
 384                             "125|%s/%s: not sourced: not owned by you or root",
 385                             b, a);
 386                         break;
 387                 case OWN:
 388                         msgq(sp, M_ERR,
 389                             "126|%s/%s: not sourced: not owned by you", b, a);
 390                         break;
 391                 case WRITER:
 392                         msgq(sp, M_ERR,
 393     "127|%s/%s: not sourced: writeable by a user other than the owner", b, a);
 394                         break;
 395                 }
 396                 if (nf2)
 397                         FREE_SPACE(sp, b, 0);
 398         } else
 399                 switch (etype) {
 400                 case ROOTOWN:
 401                         msgq(sp, M_ERR,
 402                             "128|%s: not sourced: not owned by you or root", a);
 403                         break;
 404                 case OWN:
 405                         msgq(sp, M_ERR,
 406                             "129|%s: not sourced: not owned by you", a);
 407                         break;
 408                 case WRITER:
 409                         msgq(sp, M_ERR,
 410             "130|%s: not sourced: writeable by a user other than the owner", a);
 411                         break;
 412                 }
 413
 414         if (nf1)
 415                 FREE_SPACE(sp, a, 0);
 416         return (NOPERM);
 417 }