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When the -p flag is specified, set an environment variable to the name

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of the remote host (or rather, the name as mangled by realhostname_sa())
so that the process can use it to behave differently depending on the
origin on the request.  We use this to implement rudimentary visibility
control on our user information.

Make sure that the child process's standard error goes through the same
NVT-ASCII filter as is applied to the standard output.

Don't attempt to call logerr() from the child since stdio is not safe in
a vforked process.  Just write a message to fd 2 instead.  (Ideally, the
parent would open two pipes, and siphon off our stderr to some place less
public, but I have not attempted to do so in this implementation.)
This commit is contained in:
Garrett Wollman 2002-06-26 21:46:56 +00:00
parent 713a6ea063
commit 80536ead7f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=98897
2 changed files with 30 additions and 12 deletions
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7
libexec/fingerd/fingerd.8
View File

@ -117,6 +117,13 @@ By specifying a customized local server,
this option allows a system manager
to have more control over what information is
provided to remote sites.
If
.Fl p
is specified,
.Nm
will also set the environment variable
.Ev FINGERD_REMOTE_HOST
to the name of the host making the request.
.El
.Sh SEE ALSO
.Xr finger 1 ,

35
libexec/fingerd/fingerd.c
View File

@ -71,22 +71,23 @@ main(int argc, char *argv[])
int ch;
char *lp;
struct sockaddr_storage ss;
int p[2], logging, secure, sval;
int p[2], logging, pflag, secure, sval;
#define ENTRIES 50
char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
char rhost[MAXHOSTNAMELEN];
prog = _PATH_FINGER;
logging = secure = 0;
logging = pflag = secure = 0;
openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
opterr = 0;
while ((ch = getopt(argc, argv, "slp:")) != -1)
while ((ch = getopt(argc, argv, "lp:s")) != -1)
switch (ch) {
case 'l':
logging = 1;
break;
case 'p':
prog = optarg;
pflag = 1;
break;
case 's':
secure = 1;
@ -110,6 +111,17 @@ main(int argc, char *argv[])
if (!fgets(line, sizeof(line), stdin))
exit(1);
if (logging || pflag) {
sval = sizeof(ss);
if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
logerr("getpeername: %s", strerror(errno));
realhostname_sa(rhost, sizeof rhost - 1,
(struct sockaddr *)&ss, sval);
rhost[sizeof(rhost) - 1] = '\0';
if (pflag)
setenv("FINGERD_REMOTE_HOST", rhost, 1);
}
if (logging) {
char *t;
char *end;
@ -127,12 +139,6 @@ main(int argc, char *argv[])
for (end = t; *end; end++)
if (*end == '\n' || *end == '\r')
*end = ' ';
sval = sizeof(ss);
if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
logerr("getpeername: %s", strerror(errno));
realhostname_sa(rhost, sizeof rhost - 1,
(struct sockaddr *)&ss, sval);
rhost[sizeof(rhost) - 1] = '\0';
syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
}
@ -174,12 +180,17 @@ main(int argc, char *argv[])
switch(vfork()) {
case 0:
(void)close(p[0]);
if (p[1] != 1) {
(void)dup2(p[1], 1);
if (p[1] != STDOUT_FILENO) {
(void)dup2(p[1], STDOUT_FILENO);
(void)close(p[1]);
}
dup2(STDOUT_FILENO, STDERR_FILENO);
execv(prog, comp);
logerr("execv: %s: %s", prog, strerror(errno));
write(STDERR_FILENO, prog, strlen(prog));
#define MSG ": cannot execute\n"
write(STDERR_FILENO, MSG, strlen(MSG));
#undef MSG
_exit(1);
case -1:
logerr("fork: %s", strerror(errno));