| File: | src/usr.bin/wall/wall.c |
| Warning: | line 227, column 3 The return value from the call to 'setegid' is not checked. If an error occurs in 'setegid', the following code may execute with unexpected privileges |
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| 1 | /* $OpenBSD: wall.c,v 1.35 2021/07/12 15:09:20 beck Exp $ */ |
| 2 | /* $NetBSD: wall.c,v 1.6 1994/11/17 07:17:58 jtc Exp $ */ |
| 3 | |
| 4 | /* |
| 5 | * Copyright (c) 1988, 1990, 1993 |
| 6 | * The Regents of the University of California. All rights reserved. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. Neither the name of the University nor the names of its contributors |
| 17 | * may be used to endorse or promote products derived from this software |
| 18 | * without specific prior written permission. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 30 | * SUCH DAMAGE. |
| 31 | */ |
| 32 | |
| 33 | /* |
| 34 | * This program is not related to David Wall, whose Stanford Ph.D. thesis |
| 35 | * is entitled "Mechanisms for Broadcast and Selective Broadcast". |
| 36 | */ |
| 37 | |
| 38 | #include <sys/queue.h> |
| 39 | #include <sys/stat.h> |
| 40 | #include <sys/time.h> |
| 41 | #include <sys/uio.h> |
| 42 | |
| 43 | #include <ctype.h> |
| 44 | #include <err.h> |
| 45 | #include <grp.h> |
| 46 | #include <limits.h> |
| 47 | #include <paths.h> |
| 48 | #include <pwd.h> |
| 49 | #include <stdio.h> |
| 50 | #include <stdlib.h> |
| 51 | #include <string.h> |
| 52 | #include <unistd.h> |
| 53 | #include <utmp.h> |
| 54 | |
| 55 | struct wallgroup { |
| 56 | gid_t gid; |
| 57 | char *name; |
| 58 | char **mem; |
| 59 | struct wallgroup *next; |
| 60 | } *grouplist; |
| 61 | |
| 62 | struct utmptty { |
| 63 | char *tty; |
| 64 | SLIST_ENTRY(utmptty)struct { struct utmptty *sle_next; } next; |
| 65 | }; |
| 66 | |
| 67 | void makemsg(char *); |
| 68 | void addgroup(struct group *, char *); |
| 69 | char *ttymsg(struct iovec *, int, char *, int); |
| 70 | __dead__attribute__((__noreturn__)) void usage(void); |
| 71 | static int isu8cont(unsigned char); |
| 72 | |
| 73 | int nobanner; |
| 74 | int mbufsize; |
| 75 | char *mbuf; |
| 76 | |
| 77 | /* ARGSUSED */ |
| 78 | int |
| 79 | main(int argc, char **argv) |
| 80 | { |
| 81 | FILE *fp; |
| 82 | int ch, ingroup; |
| 83 | struct iovec iov; |
| 84 | struct utmp utmp; |
| 85 | char *p, **mem; |
| 86 | char line[sizeof(utmp.ut_line) + 1]; |
| 87 | char username[sizeof(utmp.ut_name) + 1]; |
| 88 | struct passwd *pw; |
| 89 | struct group *grp; |
| 90 | struct wallgroup *g; |
| 91 | struct utmptty *un; |
| 92 | SLIST_HEAD(,utmptty)struct { struct utmptty *slh_first; } utmphead; |
| 93 | SLIST_INIT(&utmphead){ ((&utmphead)->slh_first) = ((void *)0); }; |
| 94 | |
| 95 | while ((ch = getopt(argc, argv, "ng:")) != -1) |
| 96 | switch (ch) { |
| 97 | case 'n': |
| 98 | /* undoc option for shutdown: suppress banner */ |
| 99 | pw = getpwnam("nobody"); |
| 100 | if (geteuid() == 0 || (pw && getuid() == pw->pw_uid)) |
| 101 | nobanner = 1; |
| 102 | break; |
| 103 | case 'g': |
| 104 | if ((grp = getgrnam(optarg)) == NULL((void *)0)) |
| 105 | errx(1, "unknown group `%s'", optarg); |
| 106 | addgroup(grp, optarg); |
| 107 | break; |
| 108 | default: |
| 109 | usage(); |
| 110 | } |
| 111 | argc -= optind; |
| 112 | argv += optind; |
| 113 | if (argc > 1) |
| 114 | usage(); |
| 115 | |
| 116 | makemsg(*argv); |
| 117 | |
| 118 | if (unveil(_PATH_UTMP"/var/run/utmp", "r") == -1) |
| 119 | err(1, "unveil %s", _PATH_UTMP"/var/run/utmp"); |
| 120 | if (unveil(_PATH_DEV"/dev/", "w") == -1) |
| 121 | err(1, "unveil %s", _PATH_DEV"/dev/"); |
| 122 | if (unveil(_PATH_DEVDB"/var/run/dev.db", "r") == -1) |
| 123 | err(1, "unveil %s", _PATH_DEVDB"/var/run/dev.db"); |
| 124 | if (pledge("stdio rpath wpath getpw proc", NULL((void *)0)) == -1) |
| 125 | err(1, "pledge"); |
| 126 | |
| 127 | if (!(fp = fopen(_PATH_UTMP"/var/run/utmp", "r"))) |
| 128 | err(1, "cannot read %s", _PATH_UTMP"/var/run/utmp"); |
| 129 | iov.iov_base = mbuf; |
| 130 | iov.iov_len = mbufsize; |
| 131 | |
| 132 | while (fread(&utmp, sizeof(utmp), 1, fp) == 1) { |
| 133 | if (!utmp.ut_name[0]) |
| 134 | continue; |
| 135 | if (grouplist) { |
| 136 | ingroup = 0; |
| 137 | strncpy(username, utmp.ut_name, sizeof(utmp.ut_name)); |
| 138 | username[sizeof(utmp.ut_name)] = '\0'; |
| 139 | pw = getpwnam(username); |
| 140 | if (!pw) |
| 141 | continue; |
| 142 | for (g = grouplist; g && ingroup == 0; g = g->next) { |
| 143 | if (g->gid == pw->pw_gid) |
| 144 | ingroup = 1; |
| 145 | for (mem = g->mem; *mem && ingroup == 0; mem++) |
| 146 | if (strcmp(username, *mem) == 0) |
| 147 | ingroup = 1; |
| 148 | } |
| 149 | if (ingroup == 0) |
| 150 | continue; |
| 151 | } |
| 152 | strncpy(line, utmp.ut_line, sizeof(utmp.ut_line)); |
| 153 | line[sizeof(utmp.ut_line)] = '\0'; |
| 154 | un = malloc(sizeof(struct utmptty)); |
| 155 | if (un == NULL((void *)0)) |
| 156 | err(1, "malloc"); |
| 157 | un->tty = strndup(line, sizeof(utmp.ut_line)); |
| 158 | if (un->tty == NULL((void *)0)) |
| 159 | err(1, "strndup"); |
| 160 | SLIST_INSERT_HEAD(&utmphead, un, next)do { (un)->next.sle_next = (&utmphead)->slh_first; ( &utmphead)->slh_first = (un); } while (0); |
| 161 | } |
| 162 | fclose(fp); |
| 163 | |
| 164 | if (pledge("stdio rpath wpath proc", NULL((void *)0)) == -1) |
| 165 | err(1, "pledge"); |
| 166 | |
| 167 | SLIST_FOREACH(un, &utmphead, next)for((un) = ((&utmphead)->slh_first); (un) != ((void *) 0); (un) = ((un)->next.sle_next)) { |
| 168 | if ((p = ttymsg(&iov, 1, un->tty, 60*5)) != NULL((void *)0)) |
| 169 | warnx("%s", p); |
| 170 | } |
| 171 | |
| 172 | exit(0); |
| 173 | } |
| 174 | |
| 175 | void |
| 176 | makemsg(char *fname) |
| 177 | { |
| 178 | int cnt; |
| 179 | struct tm *lt; |
| 180 | struct passwd *pw; |
| 181 | struct stat sbuf; |
| 182 | time_t now; |
| 183 | FILE *fp; |
| 184 | int fd; |
| 185 | char *p, *whom, hostname[HOST_NAME_MAX255+1], lbuf[100], tmpname[PATH_MAX1024]; |
| 186 | char *ttynam; |
| 187 | unsigned char ch; |
| 188 | |
| 189 | snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXXXXXX", _PATH_TMP"/tmp/"); |
| 190 | if ((fd = mkstemp(tmpname)) >= 0) { |
| 191 | (void)unlink(tmpname); |
| 192 | fp = fdopen(fd, "r+"); |
| 193 | } |
| 194 | if (fd == -1 || fp == NULL((void *)0)) |
| 195 | err(1, "can't open temporary file"); |
| 196 | |
| 197 | if (!nobanner) { |
| 198 | if (!(whom = getlogin())) |
| 199 | whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???"; |
| 200 | (void)gethostname(hostname, sizeof(hostname)); |
| 201 | (void)time(&now); |
| 202 | lt = localtime(&now); |
| 203 | if ((ttynam = ttyname(STDERR_FILENO2)) == NULL((void *)0)) |
| 204 | ttynam = "(not a tty)"; |
| 205 | |
| 206 | /* |
| 207 | * all this stuff is to blank out a square for the message; |
| 208 | * we wrap message lines at column 79, not 80, because some |
| 209 | * terminals wrap after 79, some do not, and we can't tell. |
| 210 | * Which means that we may leave a non-blank character |
| 211 | * in column 80, but that can't be helped. |
| 212 | */ |
| 213 | (void)fprintf(fp, "\r%79s\r\n", " "); |
| 214 | (void)snprintf(lbuf, sizeof lbuf, |
| 215 | "Broadcast Message from %s@%s", whom, hostname); |
| 216 | (void)fprintf(fp, "%-79.79s\007\007\r\n", lbuf); |
| 217 | (void)snprintf(lbuf, sizeof lbuf, |
| 218 | " (%s) at %d:%02d ...", ttynam, |
| 219 | lt->tm_hour, lt->tm_min); |
| 220 | (void)fprintf(fp, "%-79.79s\r\n", lbuf); |
| 221 | } |
| 222 | (void)fprintf(fp, "%79s\r\n", " "); |
| 223 | |
| 224 | if (fname) { |
| 225 | gid_t egid = getegid(); |
| 226 | |
| 227 | setegid(getgid()); |
The return value from the call to 'setegid' is not checked. If an error occurs in 'setegid', the following code may execute with unexpected privileges | |
| 228 | if (freopen(fname, "r", stdin(&__sF[0])) == NULL((void *)0)) |
| 229 | err(1, "can't read %s", fname); |
| 230 | setegid(egid); |
| 231 | } |
| 232 | while (fgets(lbuf, sizeof(lbuf), stdin(&__sF[0]))) |
| 233 | for (cnt = 0, p = lbuf; (ch = *p) != '\0'; ++p, ++cnt) { |
| 234 | if (cnt == 79 || ch == '\n') { |
| 235 | for (; cnt < 79; ++cnt) |
| 236 | putc(' ', fp)(!__isthreaded ? __sputc(' ', fp) : (putc)(' ', fp)); |
| 237 | putc('\r', fp)(!__isthreaded ? __sputc('\r', fp) : (putc)('\r', fp)); |
| 238 | putc('\n', fp)(!__isthreaded ? __sputc('\n', fp) : (putc)('\n', fp)); |
| 239 | cnt = -1; |
| 240 | } else if (!isu8cont(ch)) |
| 241 | putc(isprint(ch) || isspace(ch) || ch == '\a' ?(!__isthreaded ? __sputc(isprint(ch) || isspace(ch) || ch == '\a' ? ch : '?', fp) : (putc)(isprint(ch) || isspace(ch) || ch == '\a' ? ch : '?', fp)) |
| 242 | ch : '?', fp)(!__isthreaded ? __sputc(isprint(ch) || isspace(ch) || ch == '\a' ? ch : '?', fp) : (putc)(isprint(ch) || isspace(ch) || ch == '\a' ? ch : '?', fp)); |
| 243 | } |
| 244 | (void)fprintf(fp, "%79s\r\n", " "); |
| 245 | rewind(fp); |
| 246 | |
| 247 | if (fstat(fd, &sbuf)) |
| 248 | err(1, "can't stat temporary file"); |
| 249 | mbufsize = sbuf.st_size; |
| 250 | mbuf = malloc((u_int)mbufsize); |
| 251 | if (mbuf == NULL((void *)0)) |
| 252 | err(1, NULL((void *)0)); |
| 253 | if (fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize) |
| 254 | err(1, "can't read temporary file"); |
| 255 | (void)close(fd); |
| 256 | } |
| 257 | |
| 258 | void |
| 259 | addgroup(struct group *grp, char *name) |
| 260 | { |
| 261 | int i; |
| 262 | struct wallgroup *g; |
| 263 | |
| 264 | for (i = 0; grp->gr_mem[i]; i++) |
| 265 | ; |
| 266 | |
| 267 | g = malloc(sizeof *g); |
| 268 | if (g == NULL((void *)0)) |
| 269 | err(1, NULL((void *)0)); |
| 270 | g->gid = grp->gr_gid; |
| 271 | g->name = name; |
| 272 | g->mem = calloc(i + 1, sizeof(char *)); |
| 273 | if (g->mem == NULL((void *)0)) |
| 274 | err(1, NULL((void *)0)); |
| 275 | for (i = 0; grp->gr_mem[i] != NULL((void *)0); i++) { |
| 276 | g->mem[i] = strdup(grp->gr_mem[i]); |
| 277 | if (g->mem[i] == NULL((void *)0)) |
| 278 | err(1, NULL((void *)0)); |
| 279 | } |
| 280 | g->mem[i] = NULL((void *)0); |
| 281 | g->next = grouplist; |
| 282 | grouplist = g; |
| 283 | } |
| 284 | |
| 285 | void |
| 286 | usage(void) |
| 287 | { |
| 288 | extern char *__progname; |
| 289 | |
| 290 | (void)fprintf(stderr(&__sF[2]), "usage: %s [-g group] [file]\n", __progname); |
| 291 | exit(1); |
| 292 | } |
| 293 | |
| 294 | static int |
| 295 | isu8cont(unsigned char c) |
| 296 | { |
| 297 | return (c & (0x80 | 0x40)) == 0x80; |
| 298 | } |