This patch cleans up the ident stuff in inetd. The code which has
been patched so many times it was a bit of a mess. There are style, code and man page cleanups. The following are the functional changes: The RFC only permits the returning of 4 possible error codes, make sure we only return these (PR 27636). Use MAXLOGNAME to determine the longest usernames. Add a -i flag, which returns the uid instead of the username (this is from a PR 25787, which also contained alot of the cleanups in this patch). PR: 25787, 27636 Partially Submitted by: Arne.Dag.Fidjestol@idi.ntnu.no Reviewed by: Arne.Dag.Fidjestol@idi.ntnu.no, green MFC after: 3 weeks
This commit is contained in:
David Malone
parent
0becf102d7
commit
9a0b3389d5
@ -306,15 +306,21 @@ echo_stream(s, sep) /* Echo service -- echo data back */
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* support.
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*/
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/* RFC 1413 says the following are the only errors you can return. */
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#define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */
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#define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */
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#define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */
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#define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */
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/* ARGSUSED */
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void
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iderror(lport, fport, s, er) /* Generic ident_stream error-sending func */
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int lport, fport, s, er;
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int lport, fport, s;
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char *er;
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{
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char *p;
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asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport,
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er == -1 ? "HIDDEN-USER" : er ? strerror(er) : "UNKNOWN-ERROR");
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asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
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if (p == NULL) {
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syslog(LOG_ERR, "asprintf: %m");
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exit(EX_OSERR);
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@ -345,13 +351,13 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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}, to;
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struct passwd *pw = NULL;
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fd_set fdset;
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char buf[BUFSIZE], *cp = NULL, *p, **av, *osname = NULL, garbage[7], e;
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char *fallback = NULL;
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char buf[BUFSIZE], *p, **av, *osname = NULL, e;
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char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
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socklen_t socklen;
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ssize_t ssize;
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size_t size, bufsiz;
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int c, fflag = 0, nflag = 0, rflag = 0, argc = 0, usedfallback = 0;
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int gflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
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int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
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int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
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u_short lport, fport;
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inetd_setproctitle(sep->se_service, s);
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@ -373,10 +379,11 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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size_t i;
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u_int32_t random;
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while ((c = getopt(argc, sep->se_argv, "d:fFgno:rt:")) != -1)
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while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
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switch (c) {
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case 'd':
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fallback = optarg;
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if (!gflag)
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strlcpy(idbuf, optarg, sizeof(idbuf));
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break;
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case 'f':
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fflag = 1;
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@ -394,21 +401,22 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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* gives a more optimal way to reload the
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* random number only when necessary.
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*
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* I'm using base-36, so I need at least 6
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* bits; round it up to 8 bits to make it
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* easier.
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* 32 bits from arc4random corrisponds to
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* about 6 base-36 digits, so we reseed evey 6.
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*/
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for (i = 0; i < sizeof(garbage) - 1; i++) {
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const char *const base36 =
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for (i = 0; i < sizeof(idbuf) - 1; i++) {
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static const char *const base36 =
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"0123456789"
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"abcdefghijklmnopqrstuvwxyz";
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if (i % (sizeof(random) * 8 / 8) == 0)
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if (i % 6 == 0)
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random = arc4random();
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garbage[i] =
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base36[(random & 0xff) % 36];
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random >>= 8;
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idbuf[i] = base36[random % 36];
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random /= 36;
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}
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garbage[i] = '\0';
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idbuf[i] = '\0';
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break;
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case 'i':
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iflag = 1;
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break;
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case 'n':
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nflag = 1;
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@ -423,6 +431,7 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
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case 2:
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tv.tv_usec = usec;
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/* FALLTHROUGH */
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case 1:
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tv.tv_sec = sec;
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break;
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@ -438,15 +447,10 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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}
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if (osname == NULL) {
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if (uname(&un) == -1)
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iderror(0, 0, s, errno);
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iderror(0, 0, s, ID_UNKNOWN);
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osname = un.sysname;
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}
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socklen = sizeof(ss[0]);
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if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
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iderror(0, 0, s, errno);
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socklen = sizeof(ss[1]);
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if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
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iderror(0, 0, s, errno);
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/*
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* We're going to prepare for and execute reception of a
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* packet of data from the user. The data is in the format
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@ -476,14 +480,14 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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break;
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FD_SET(s, &fdset);
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if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
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iderror(0, 0, s, errno);
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iderror(0, 0, s, ID_UNKNOWN);
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if (ioctl(s, FIONREAD, &onreadlen) == -1)
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iderror(0, 0, s, errno);
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iderror(0, 0, s, ID_UNKNOWN);
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if (onreadlen > bufsiz)
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onreadlen = bufsiz;
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ssize = read(s, &buf[size], (size_t)onreadlen);
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if (ssize == -1)
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iderror(0, 0, s, errno);
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iderror(0, 0, s, ID_UNKNOWN);
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else if (ssize == 0)
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break;
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bufsiz -= ssize;
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@ -494,37 +498,38 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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buf[size] = '\0';
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/* Read two characters, and check for a delimiting character */
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if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
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iderror(0, 0, s, 0);
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if (gflag) {
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cp = garbage;
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iderror(0, 0, s, ID_INVALID);
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/* Send garbage? */
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if (gflag)
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goto printit;
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}
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/*
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* If not "real" (-r), send a HIDDEN-USER error for everything.
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* If -d is used to set a fallback username, this is used to
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* override it, and the fallback is returned instead.
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*/
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if (!rflag) {
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if (fallback == NULL)
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iderror(lport, fport, s, -1);
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else {
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cp = fallback;
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goto printit;
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}
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if (*idbuf == '\0')
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iderror(lport, fport, s, ID_HIDDEN);
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goto printit;
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}
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/*
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* We take the input and construct an array of two sockaddr_ins
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* which contain the local address information and foreign
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* address information, respectively, used to look up the
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* credentials for the socket (which are returned by the
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* sysctl "net.inet.tcp.getcred" when we call it.) The
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* arrays have been filled in above via get{peer,sock}name(),
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* so right here we are only setting the ports.
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* sysctl "net.inet.tcp.getcred" when we call it.)
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*/
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socklen = sizeof(ss[0]);
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if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
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iderror(lport, fport, s, ID_UNKNOWN);
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socklen = sizeof(ss[1]);
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if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
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iderror(lport, fport, s, ID_UNKNOWN);
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if (ss[0].ss_family != ss[1].ss_family)
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iderror(lport, fport, s, EINVAL);
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iderror(lport, fport, s, ID_UNKNOWN);
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size = sizeof(uc);
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switch (ss[0].ss_family) {
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case AF_INET:
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@ -552,48 +557,54 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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break;
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}
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if (getcredfail != 0) {
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if (fallback == NULL) /* Use a default, if asked to */
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iderror(lport, fport, s, getcredfail);
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usedfallback = 1;
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} else {
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/* Look up the pw to get the username */
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errno = 0;
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pw = getpwuid(uc.cr_uid);
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if (*idbuf == '\0')
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iderror(lport, fport, s,
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getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
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goto printit;
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}
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if (pw == NULL && !usedfallback) /* No such user... */
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iderror(lport, fport, s, errno != 0 ? errno : ENOENT);
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/* Look up the pw to get the username and home directory*/
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errno = 0;
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pw = getpwuid(uc.cr_uid);
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if (pw == NULL)
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iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
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if (iflag)
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snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
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else
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strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
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/*
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* If enabled, we check for a file named ".noident" in the user's
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* home directory. If found, we return HIDDEN-USER.
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*/
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if (nflag && !usedfallback) {
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if (nflag) {
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if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
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iderror(lport, fport, s, errno);
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iderror(lport, fport, s, ID_UNKNOWN);
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if (lstat(p, &sb) == 0) {
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free(p);
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iderror(lport, fport, s, -1);
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iderror(lport, fport, s, ID_HIDDEN);
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}
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free(p);
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}
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/*
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* Here, if enabled, we read a user's ".fakeid" file in their
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* home directory. It consists of a line containing the name
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* they want.
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*/
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if (fflag && !usedfallback) {
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FILE *fakeid = NULL;
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if (fflag) {
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int fakeid_fd;
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if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
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iderror(lport, fport, s, errno);
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/*
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* Here we set ourself to effectively be the user, so we don't
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* open any files we have no permission to open, especially
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* symbolic links to sensitive root-owned files or devices.
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*/
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if (initgroups(pw->pw_name, pw->pw_gid) == -1)
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iderror(lport, fport, s, errno);
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seteuid(pw->pw_uid);
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iderror(lport, fport, s, ID_UNKNOWN);
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if (seteuid(pw->pw_uid) == -1)
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iderror(lport, fport, s, ID_UNKNOWN);
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/*
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* We can't stat() here since that would be a race
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* condition.
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@ -601,60 +612,58 @@ ident_stream(s, sep) /* Ident service (AKA "auth") */
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* and if it's not a regular file, we close it and end up
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* returning the user's real username.
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*/
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if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
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iderror(lport, fport, s, ID_UNKNOWN);
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fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
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free(p);
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if (fakeid_fd != -1 && fstat(fakeid_fd, &sb) != -1 &&
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S_ISREG(sb.st_mode) &&
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(fakeid = fdopen(fakeid_fd, "r")) != NULL) {
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buf[sizeof(buf) - 1] = '\0';
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if (fgets(buf, sizeof(buf), fakeid) == NULL) {
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cp = pw->pw_name;
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fclose(fakeid);
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goto printit;
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if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
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!S_ISREG(sb.st_mode))
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goto fakeid_fail;
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if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
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goto fakeid_fail;
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buf[ssize] = '\0';
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/*
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* Usually, the file will have the desired identity
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* in the form "identity\n". Allow for leading white
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* space and trailing white space/end of line.
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*/
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p = buf;
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p += strspn(p, " \t");
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p[strcspn(p, " \t\r\n")] = '\0';
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if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
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p[MAXLOGNAME - 1] = '\0';
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/*
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* If the name is a zero-length string or matches it
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* the id or name of another user (unless permitted by -F)
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* then it is invalid.
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*/
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if (*p == '\0')
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goto fakeid_fail;
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if (!Fflag) {
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if (iflag) {
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if (p[strspn(p, "0123456789")] == '\0' &&
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getpwuid(atoi(p)) != NULL)
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goto fakeid_fail;
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} else {
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if (getpwnam(p) != NULL)
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goto fakeid_fail;
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}
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/*
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* Usually, the file will have the desired identity
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* in the form "identity\n", so we use strcspn() to
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* end the string (which fgets() doesn't do.)
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*/
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buf[strcspn(buf, "\r\n")] = '\0';
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cp = buf;
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/* Allow for beginning white space... */
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while (isspace(*cp))
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cp++;
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/* ...and ending white space. */
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cp[strcspn(cp, " \t")] = '\0';
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/* User names of >16 characters are invalid */
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if (strlen(cp) > 16)
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cp[16] = '\0';
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/*
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* If the name is a zero-length string or matches
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* the name of another user, it's invalid, so
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* we will return their real identity instead.
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*/
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if (!*cp || (!Fflag && getpwnam(cp))) {
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errno = 0;
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pw = getpwuid(uc.cr_uid);
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if (pw == NULL)
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iderror(lport, fport, s,
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errno != 0 ? errno : ENOENT);
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cp = pw->pw_name;
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}
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} else
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cp = pw->pw_name;
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if (fakeid != NULL)
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fclose(fakeid);
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else if (fakeid_fd != -1)
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}
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strlcpy(idbuf, p, sizeof(idbuf));
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fakeid_fail:
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if (fakeid_fd != -1)
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close(fakeid_fd);
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} else if (!usedfallback)
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cp = pw->pw_name;
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else
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cp = fallback;
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}
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printit:
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/* Finally, we make and send the reply. */
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if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
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cp) == -1) {
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idbuf) == -1) {
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syslog(LOG_ERR, "asprintf: %m");
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exit(EX_OSERR);
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}
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@ -455,6 +455,21 @@ If the real
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service is disabled,
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return this username for every request.
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This is primarily useful when running this service on a NAT machine.
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.It Fl g
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Instead of returning
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the user's name to the ident requester,
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report a
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username made up of random alphanumeric characters,
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e.g.
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.Dq c0c993 .
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The
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.Fl g
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flag overrides not only the user names,
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but also any fallback name,
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.Pa .fakeid
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or
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.Pa .noident
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files.
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.It Fl t Xo
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.Ar sec Ns Op . Ns Ar usec
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.Xc
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@ -465,6 +480,8 @@ Offer a real
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.Dq auth
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service, as per RFC 1413.
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All the remaining flags apply only in this case.
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.It Fl i
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Return numeric user IDs instead of usernames.
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.It Fl f
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If the file
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.Pa .fakeid
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@ -474,29 +491,25 @@ If the the username found in
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.Pa .fakeid
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is that of an existing user,
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then the real username is reported.
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If the
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.Fl i
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flag is also given then the username in
|
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.Pa .fakeid
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is checked against existing user IDs instead.
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.It Fl F
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same as
|
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.Fl f
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but without the restriction that the username in
|
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.Pa .fakeid
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must not match an existing user.
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.It Fl g
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Instead of returning the user's name to the ident requester, report a
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username made up of random alphanumeric characters, e.g.
|
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.Dq c0c993 .
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The
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.Fl g
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flag overrides not only the user names, but also any
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.Pa .fakeid
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or
|
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.Pa .noident
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files.
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.It Fl n
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If the file
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.Pa .noident
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exists in the home directory of the identified user, return
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.Dq ERROR\ : HIDDEN-USER .
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instead.
|
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This overrides any
|
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.Pa fakeid
|
||||
file which might exist.
|
||||
.It Fl o Ar osname
|
||||
Use
|
||||
.Ar osname
|
||||
|
||||
@ -122,7 +122,7 @@ void endconfig __P((void));
|
||||
struct servtab *enter __P((struct servtab *));
|
||||
void freeconfig __P((struct servtab *));
|
||||
struct servtab *getconfigent __P((void));
|
||||
void iderror __P((int, int, int, int));
|
||||
void iderror __P((int, int, int, char *));
|
||||
void ident_stream __P((int, struct servtab *));
|
||||
void machtime_dg __P((int, struct servtab *));
|
||||
void machtime_stream __P((int, struct servtab *));
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user