| File: | src/libexec/fingerd/fingerd.c |
| Warning: | line 203, column 10 Call to function 'vfork' is insecure as it can lead to denial of service situations in the parent process. Replace calls to vfork with calls to the safer 'posix_spawn' function |
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| 1 | /* $OpenBSD: fingerd.c,v 1.42 2021/07/12 15:09:18 beck Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 1983, 1993 |
| 5 | * The Regents of the University of California. All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * 3. Neither the name of the University nor the names of its contributors |
| 16 | * may be used to endorse or promote products derived from this software |
| 17 | * without specific prior written permission. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 23 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 28 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 29 | * SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | #include <sys/socket.h> |
| 33 | #include <netinet/in.h> |
| 34 | #include <arpa/inet.h> |
| 35 | #include <errno(*__errno()).h> |
| 36 | |
| 37 | #include <err.h> |
| 38 | #include <unistd.h> |
| 39 | #include <syslog.h> |
| 40 | #include <netdb.h> |
| 41 | #include <stdio.h> |
| 42 | #include <stdlib.h> |
| 43 | #include <string.h> |
| 44 | #include <stdarg.h> |
| 45 | #include <limits.h> |
| 46 | #include "pathnames.h" |
| 47 | |
| 48 | __dead__attribute__((__noreturn__)) void logerr(const char *, ...); |
| 49 | __dead__attribute__((__noreturn__)) void usage(void); |
| 50 | |
| 51 | void |
| 52 | usage(void) |
| 53 | { |
| 54 | syslog(LOG_ERR3, |
| 55 | "usage: fingerd [-lMmpSsu] [-P filename]"); |
| 56 | exit(2); |
| 57 | } |
| 58 | |
| 59 | |
| 60 | int |
| 61 | main(int argc, char *argv[]) |
| 62 | { |
| 63 | FILE *fp; |
| 64 | int ch, ac = 2; |
| 65 | int p[2], logging, secure, user_required, short_list; |
| 66 | #define ENTRIES50 50 |
| 67 | char **comp, *prog; |
| 68 | char **ap, *av[ENTRIES50 + 1], line[8192], *lp, *hname; |
| 69 | char hostbuf[HOST_NAME_MAX255+1]; |
| 70 | |
| 71 | prog = _PATH_FINGER"/usr/bin/finger"; |
| 72 | logging = secure = user_required = short_list = 0; |
| 73 | openlog("fingerd", LOG_PID0x01, LOG_DAEMON(3<<3)); |
| 74 | opterr = 0; |
| 75 | while ((ch = getopt(argc, argv, "sluSmMpP:")) != -1) |
| 76 | switch (ch) { |
| 77 | case 'l': |
| 78 | logging = 1; |
| 79 | break; |
| 80 | case 'P': |
| 81 | prog = optarg; |
| 82 | break; |
| 83 | case 's': |
| 84 | secure = 1; |
| 85 | break; |
| 86 | case 'u': |
| 87 | user_required = 1; |
| 88 | break; |
| 89 | case 'S': |
| 90 | if (ac < ENTRIES50) { |
| 91 | short_list = 1; |
| 92 | av[ac++] = "-s"; |
| 93 | } |
| 94 | break; |
| 95 | case 'm': |
| 96 | if (ac < ENTRIES50) |
| 97 | av[ac++] = "-m"; |
| 98 | break; |
| 99 | case 'M': |
| 100 | if (ac < ENTRIES50) |
| 101 | av[ac++] = "-M"; |
| 102 | break; |
| 103 | case 'p': |
| 104 | if (ac < ENTRIES50) |
| 105 | av[ac++] = "-p"; |
| 106 | break; |
| 107 | default: |
| 108 | usage(); |
| 109 | } |
| 110 | |
| 111 | if (unveil(prog, "x") == -1) |
| 112 | err(1, "unveil %s", prog); |
| 113 | if (pledge("stdio inet dns proc exec", NULL((void *)0)) == -1) |
| 114 | err(1, "pledge"); |
| 115 | |
| 116 | if (logging) { |
| 117 | struct sockaddr_storage ss; |
| 118 | struct sockaddr *sa; |
| 119 | socklen_t sval; |
| 120 | |
| 121 | sval = sizeof(ss); |
| 122 | if (getpeername(0, (struct sockaddr *)&ss, &sval) == -1) |
| 123 | err(1, "getpeername"); |
| 124 | sa = (struct sockaddr *)&ss; |
| 125 | |
| 126 | if (pledge("stdio dns proc exec", NULL((void *)0)) == -1) |
| 127 | err(1, "pledge"); |
| 128 | |
| 129 | if (getnameinfo(sa, sa->sa_len, hostbuf, sizeof(hostbuf), |
| 130 | NULL((void *)0), 0, 0) != 0) { |
| 131 | strlcpy(hostbuf, "?", sizeof(hostbuf)); |
| 132 | } |
| 133 | hname = hostbuf; |
| 134 | } |
| 135 | |
| 136 | if (pledge("stdio proc exec", NULL((void *)0)) == -1) |
| 137 | err(1, "pledge"); |
| 138 | |
| 139 | if (fgets(line, sizeof(line), stdin(&__sF[0])) == NULL((void *)0)) { |
| 140 | if (logging) |
| 141 | syslog(LOG_NOTICE5, "query from %s: %s", hname, |
| 142 | feof(stdin)(!__isthreaded ? ((((&__sF[0]))->_flags & 0x0020) != 0) : (feof)((&__sF[0]))) ? "EOF" : strerror(errno(*__errno()))); |
| 143 | exit(1); |
| 144 | } |
| 145 | |
| 146 | if (logging) |
| 147 | syslog(LOG_NOTICE5, "query from %s: `%.*s'", hname, |
| 148 | (int)strcspn(line, "\r\n"), line); |
| 149 | |
| 150 | /* |
| 151 | * Note: we assume that finger(1) will treat "--" as end of |
| 152 | * command args (ie: that it uses getopt(3)). |
| 153 | */ |
| 154 | av[ac++] = "--"; |
| 155 | comp = &av[1]; |
| 156 | for (lp = line, ap = &av[ac]; ac < ENTRIES50;) { |
| 157 | size_t len; |
| 158 | |
| 159 | if ((*ap = strtok(lp, " \t\r\n")) == NULL((void *)0)) |
| 160 | break; |
| 161 | lp = NULL((void *)0); |
| 162 | if (secure && strchr(*ap, '@')) { |
| 163 | (void) puts("forwarding service denied\r"); |
| 164 | exit(1); |
| 165 | } |
| 166 | |
| 167 | len = strlen(*ap); |
| 168 | while (len > 0 && (*ap)[len - 1] == '@') |
| 169 | (*ap)[--len] = '\0'; |
| 170 | if (**ap == '\0') |
| 171 | continue; |
| 172 | |
| 173 | /* RFC1196: "/[Ww]" == "-l" */ |
| 174 | if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) { |
| 175 | if (!short_list) { |
| 176 | av[1] = "-l"; |
| 177 | comp = &av[0]; |
| 178 | } |
| 179 | } else { |
| 180 | ap++; |
| 181 | ac++; |
| 182 | } |
| 183 | } |
| 184 | av[ENTRIES50 - 1] = NULL((void *)0); |
| 185 | |
| 186 | if ((lp = strrchr(prog, '/'))) |
| 187 | *comp = ++lp; |
| 188 | else |
| 189 | *comp = prog; |
| 190 | |
| 191 | if (user_required) { |
| 192 | for (ap = comp + 1; strcmp("--", *(ap++)); ) |
| 193 | ; |
| 194 | if (*ap == NULL((void *)0)) { |
| 195 | (void) puts("must provide username\r"); |
| 196 | exit(1); |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | if (pipe(p) == -1) |
| 201 | logerr("pipe: %s", strerror(errno(*__errno()))); |
| 202 | |
| 203 | switch (vfork()) { |
Call to function 'vfork' is insecure as it can lead to denial of service situations in the parent process. Replace calls to vfork with calls to the safer 'posix_spawn' function | |
| 204 | case 0: |
| 205 | (void) close(p[0]); |
| 206 | if (p[1] != 1) { |
| 207 | (void) dup2(p[1], 1); |
| 208 | (void) close(p[1]); |
| 209 | } |
| 210 | execv(prog, comp); |
| 211 | syslog(LOG_ERR3, "execv: %s: %s", prog, strerror(errno(*__errno()))); |
| 212 | _exit(1); |
| 213 | case -1: |
| 214 | logerr("fork: %s", strerror(errno(*__errno()))); |
| 215 | } |
| 216 | if (pledge("stdio", NULL((void *)0)) == -1) |
| 217 | err(1, "pledge"); |
| 218 | |
| 219 | (void) close(p[1]); |
| 220 | if (!(fp = fdopen(p[0], "r"))) |
| 221 | logerr("fdopen: %s", strerror(errno(*__errno()))); |
| 222 | while ((ch = getc(fp)(!__isthreaded ? (--(fp)->_r < 0 ? __srget(fp) : (int)( *(fp)->_p++)) : (getc)(fp))) != EOF(-1)) { |
| 223 | if (ch == '\n') |
| 224 | putchar('\r')(!__isthreaded ? __sputc('\r', (&__sF[1])) : (putc)('\r', (&__sF[1]))); |
| 225 | putchar(ch)(!__isthreaded ? __sputc(ch, (&__sF[1])) : (putc)(ch, (& __sF[1]))); |
| 226 | } |
| 227 | exit(0); |
| 228 | } |
| 229 | |
| 230 | void |
| 231 | logerr(const char *fmt, ...) |
| 232 | { |
| 233 | va_list ap; |
| 234 | |
| 235 | va_start(ap, fmt)__builtin_va_start(ap, fmt); |
| 236 | (void) vsyslog(LOG_ERR3, fmt, ap); |
| 237 | va_end(ap)__builtin_va_end(ap); |
| 238 | exit(1); |
| 239 | } |