- If you take the wheel entry out of /etc/group and turn on NIS,
the '+:*::' line is incorrectly flagged as the entry for wheel (the
empty gid section is translated to 0), hence getgrgid() returns '+'
as the name of the group instead of 'wheel.'
- Using just '+:' as the 'turn on NIS' switch in /etc/group makes
getgrgid() dump core because of a null pointer dereference. (Last
time I was in here, I foolishly assumed that fixing the core dump
problems with getgrnam() and getgrent() would fix getgrgid() too.
Silly me.)
- Moved to a more client-driven model. We aggressively attempt to keep
the default domain bound (as before) but we give up on non-default
domains if we lose contact with a server and fail to get a response
after one round of broadcasting. This helps drastically reduce the
amount of network bandwitdh that ypbind consumes: if a client references
the secondary domain at some later point, this will prod ypbind into
establishing a new binding anyway, so continuously broadcasting without
need is pointless.
Note that we still actively seek out a binding for our default domain
even if no client program has queried us yet. I'm not exactly sure if
this matches SunOS's behavior or not, but I decided to do it this way
since we can get into all sorts of trouble if our default domain comes
unbound. Even so, we're still much quieter than we used to be.
- Removed a bunch of no-longer pertinent comments and a couple of
chunks of #ifdef 0'ed code that no longer fit in to the new layout.
- Theo deRaadt must have become frustrated with the callback mechanism
in clnt_broadcast(), because he shamelessly stole the clnt_broadcast()
code right out of the RPC library and hacked it up to suit his needs.
(Comments and all! :)
I can understand why: clnt_broadcast() blocks while awaiting replies.
Changing this behavior requires surgery. However, you can work around
this: fork the broadcast into a child process and relay the results
back to the parent via a pipe. (Careful obervation has shown that the
SunOS ypbind forks children for broadcasting too, though I can only
guess what sort of interprocess communication it uses. pipe() seems to
do the job well enough.)
This may seem like the long way around, but it's not really that
hard to implement, and I'd prefer to use documented RPC library functions
wherever possible. We're careful to limit the number of simultaneous
broadcasters to avoid swamping the system (the current limit is 5).
Each clnt_broadcast() call only sends out a small number of packets
at increasing intervals. We're also careful not to spawn more than one
bradcaster for a given domain.
- Used clntudp_bufcreate() and clnt_call() to implement a ping()
function for directly querying a particular server so that we can
check if it's still alive. This lets me completely remove the old
bradcasting code and use actual RPC library calls instead, at the
cost of more than a few handfulls of torn-out hair. (Make no mistake
folks: I *HATE* RPC.) Currently, the ping interval is one minute.
- Fixed another potential 'nfds too big for select()' bug: use
_rpc_dtablesize() instead of getdtablesize().
- Quieted gcc -Wall a bit.
- Probably a bunch of other stuff that I've forgotten.
ypbind.8:
- Updated man page to reflect modifications.
ypwhich.c:
- Small mind-o fix from last time: decode error results from
ypbind correctly (*groan*)
yplib.c:
- same as above
- Change behavior of _yp_dobind() a little: if we get back a 'Domain
not bound' error for a given domain, retry a few times before giving
up and passing the error back to the caller. We have to sleep for a
few seconds between tries since the 'Domain not bound' error comes
back immediately (by repeatedly looping, we end up pounding on ypbind).
We retry at most 20 times at 5 second intervals. This gives us a full
minute to get a response. This seems to deviate a bit from SunOS
behavior -- it appears to wait forever -- but I don't like the idea
of perpetually hanging inside a library call.
Note that this should fix the problems some people have with bindings
not being established fast enough at boot time; sometimes amd is started
in /etc/rc after ypbind has run but before it gets a binding set up. The
automounter gets annoyed at this and tends to exit. By pausing ther YP
calls until a binding is ready, we avoid this situation.
- Another _yp_dobind() change: if we determine that our binding files
are unlocked or nonexistent, jump directly to code that pokes ypbind
into restablishing the binding. Again, if it fails, we'll time out
eventually and return.
ypbind.c: if a client program asks ypbind for the name of the server
for a particular domain, and there isn't a binding for that domain
available yet, ypbind needs to supply a status value along with its
failure message. Set yprespbody.ypbind_error before returning from
a ypbindproc_domain request.
yplib.c: properly handle the error status messages ypbind now has the
ability to send us. Add a ypbinderr_string() function to decode the
error values.
ypwhich.c: handle ypbind errors correctly: yperr_string() can't handle
ypbind_status messages -- use ypbinderr_string instead.
- it succeeded on non-directories (see POSIX 5.1.2.4).
- it hung on (non-open) named pipes.
- it leaked memory if the second malloc() failed.
- it didn't preserve errno across errors in close().
of the plus or minus lists at all, reject him. This lets you create
a +@netgroup list of users that you want to admit and reject everybody
else. If you end your +@netgroup list with the wildcard line
(+:::::::::) then you'll have a +@netgroup list that remaps the
specified people but leaves people not in any netgroup unaffected.
where one or more of the non-default domains are not yet bound.
If we make a YP request for a domain other than the default domain,
and there is no binding for the new domain yet, _yp_dobind() sees
that the /var/yp/binding/DOMAIN.VERS file for the unbound domain is
not locked (by ypbind) and from this it concludes that the NIS system
is dead, so it gives up.
This behavior has been changed: before giving up in this case, we now
make a second check to see if the binding file for the *default* domain
is also not locked. Only if the default domain binding file is also
unlocked to we now assume that ypbind has bought the farm and bail out.
(Note: this assumes that the user hasn't changed the default domain
while ypbind is running.)
With this change, _do_ypbind() is allowed to proceed into the next
section of code wherein it prods ypbind into establishing a binding
for the new domain. This first call times out after ten seconds,
after which it should retry and succeed. From then on, the binding
for the second domain should be handled normally.
isctype.c:
o The tolower() and toupper() functions duplicated too much code
and were out of date (surprise). This didn't matter because
it was difficult to call them.
o Change formatting to be more like that in <ctype.h> (with
extra parentheses as in the macros). Perhaps this file should
be machine generated or everything should be handled like
__tolower() so that no code is repeated.
nomacros.c:
o Instead of looking at _USE_CTYPE_INLINE_ to see what <ctype.h>
has done, set _EXTERNALIZE_CTYPE_INLINES_ to tell <ctype.h>
what to do, so that we don't have anything left to do. Note
that code is now generated even if inlines are used by default.
This allows users to switch to non-inline versions.
select() returns EINVAL if you try to feed it a value of FD_SETSIZE greater
that 256. You can apparently adjust this by specifying a larger value of
FD_SETSIZE when configuring your kernel. However, if you set the maximum
number of open file descriptors per process to some value greater than
the FD_SETSIZE value that select() expects, many selects() within the RPC
library code will be botched because _rpc_dtablesize() will return
invalid numbers. This is to say that it will return the upper descriptor
table size limit which can be much higher than 256. Unless select() is
prepared to expect this 'unusually' high value, it will fail. (A good
example of this can be seen with NIS enabled: if you type 'unlimit' at
the shell prompt and then run any command that does NIS calls, you'll
be bombarded with errors from clnttcp_create().)
A temporary fix for this is to clamp the value returned by _rpc_dtablesize()
at FD_SETSIZE (as defined in <sys/types.h> (256)). I suppose the Right
Thing would be to provide some mechanism for select() to dynamically
adjust itself to handle FD_SETSIZE values larger than 256, but it's a
bit late in the game for that. Hopefully 256 file descriptors will be enough
to keep RPC happy for now.
add #includes for YP headers when compiling with -DYP to avoid some implicit
declarations.
getgrent.c & getnetgrent.c: add some #includes to avoid implicit declarations
of YP functions.
Obtained from: Casper H. Dik (by vay of Usenet)
Small patch to help improve NIS rebinding times (among other things):
>From: casper@fwi.uva.nl (Casper H.S. Dik)
>Newsgroups: comp.sys.sun.misc,comp.sys.sun.admin
>Subject: FIX for slow rebinding of NIS.
>Summary: a small change in libc makes life with NIS a lot easier.
>Message-ID: <1992Jan17.173905.11727@fwi.uva.nl>
>Date: 17 Jan 92 17:39:05 GMT
>Sender: news@fwi.uva.nl
>Organization: FWI, University of Amsterdam
>Lines: 138
>Nntp-Posting-Host: halo.fwi.uva.nl
Have you been plagued by long waits when your NIS server is rebooted?
READ ON!
Sun has a patch, but the README says:
********************* WARNING ******************************
This is a new version of ypbind that never uses the NIS
binding file to cache the servers binding. This will have
the effect of fixing the current symptom. However, it might
degrade the overall performance of the system when the
server is available. This is most likely to happen on an
overloaded server, which will cause the network to produce
a broadcast storm.
*************************************************************
Therefor, I have produced another fix.
o What goes wrong.
When the NIS server is rebooted, ypserv will obtain different ports
to listen for RPC requests. All clients will continue to use the old
binding they obtained earlier. The NIS server will send ICMP dst unreachable
messages for the RPC requests that arrive at the old port. These ICMPs
are dropped on the floor and the client code will continue sending the
requests until the timer has expired. The small fix at the end of this
message will pick up these ICMP messages and deliver them to the RPC layer.
o Before and after.
I've tested this on some machines and this is the result:
(kill and restart ypserv on the server)
original% time ypmatch user passwd
user:....
0.040u 0.090s 2:35.64 0.0% 0+126k 0+0io 0pf+0w (155 seconds elapsed time)
fixedhost% time ypmatch user passwd
user:....
0.050u 0.050s 0:10.20 0.9% 0+136k 0+0io 0pf+0w (10 seconds elapsed time)
Rebinding is almost instantaneous.
o Other benefits.
RPC calls that use UDP as transport will no longer time out but
will abort much sooner. (E.g., the remote host is unreachable or
111/udp is filtered by an intermediate router)
Grrr. If the dbhash routines weren't grossly overengineered I wouldn't
even need to do this! :-(
Also now export the hash_stats routine. Manpage coming RSN - I promise.
Make sure all arguments to the yp_*() functions are valid before sending
them off to the server. This is somewhat distressing: once again my
FreeBSD box brought down my entire network because of NIS bogosities.
I *think* the poor argument checking in this module is the cause, but
I still haven't been able to reproduce the exact series of events that
lead to the ypserv crashes. For now I've resorted to sticking my FreeBSD
box in a seprate domain. Hopefully a weekend of heavy testing will
uncover the problem.
Change strtok() to strsep(), cause memory corruption for all
programs which use strtok() too in the same time.
Fix potential NULL reference, depends of /etc/hosts.conf format
Fix the bug when service name fetched always from beginning of the line,
not from parsed token.
programs which use strtok() too in the same time.
Fix potential NULL reference, depends of /etc/hosts.conf format
Fix the bug when service name fetched always from beginning of the line,
not from parsed token.
remapping mechanism in the following manner: if given an entry +@foo
and there is no netgroup named 'foo,' try searching for a regular
user group called 'foo' and build the cache using the members of
group 'foo' instead. If both a netgroup 'foo' and a user group 'foo'
exist, the 'foo' netgroup takes precedence, since we're primarily
interested in netgroup matching anyway.
This allows access control schemes based on ordinary user groups
(which are also available via NIS) rather than netgroups, since
netgroups on some systems are limited in really brain-damaged ways.
ypserv to do a yp_match() with an a null or empty key causes much havok.
(Note that this could be construed as a denial of service attack if used
maliciously.)
my network because setnetgrent() was trying to do a lookup on group "".
It seems that an attempt to do a yp_match() (and possible yp_next())
on a null or empty key causes Sun's ypserv in SunOS 4.1.3 to exit
suddenly (and without warning). Our ypserv behaves badly in this
situation too, thoush it doesn't appear to crash. In any event, getpwent,
getnetgrent and yp_match() and yp_next() are now extra careful not to
accidentally pass on null or empty arguments.
Also made a small change to getpwent.c to allow +::::::::: wildcarding,
which I had disabled previously.
- Have the +@netgroup/-@netgroup caches handle the +user/-user cases too.
- Clean up getpwent() to take advantage of the improved +user/-user handling.
Submitted by: Sebastian Strollo <seb@erix.ericsson.se>
- In /usr/src/lib/libc/yp/yplib.c, function yp_first when clnt_call
fails with (r != RPC_SUCCESS) ysd->dom_vers should be set to 0! This
ensures that /var/yp/bindings/dom.vers will be read again on retry.
What happens now is that when our server is down and someone tries to
use yp they will continue to try until kingdom come. So:
if(r != RPC_SUCCESS) {
clnt_perror(ysd->dom_client, "yp_first: clnt_call");
ysd->dom_vers = -1;
^^^^ change to 0
goto again;
}
that everyone else does: you can now use +host/-host, +user,-user and
+@netgroup/-@netgroup in /etc/hosts.equiv, /.rhosts, /etc/hosts.lpd and
~/.rhosts. Previously, __ivaliduser would only do host/user matches,
which was lame. This affects all the r-commands, lpd, and any other
program/service that uses ruserok().
An example of the usefullness of this feature would be a hosts.equiv
file that looks like this:
+@equiv-hosts
Since the netgroup database can now be accessed via NIS, this lets you
set up client machines once and then never have to worry about them
again: all hosts.equiv changes can now be done through NIS. Once I
finish with getpwent.c, we'll be able to do similar wacky things
with login authentication too. (Our password field substitution
will finally be on par with everyone else's, and I'll finally be
able to fully integrate my FreeBSD machine into my network without
having to worry about the grad students sneaking into it when I'm
not looking. :)
Danger Will Robinson! I tested this thing every which way I could, but
Murphy's Law applies! If anybody spots a potential security problem with
the way my matching algorithm works, tell me immediately! I don't want
crackers snickering and calling me names behind my back. :)
work because parse_netgrp() doesn't recurse properly. Fixed by
changing
if (parse_netgrp(spos))
return(1);
to
if (parse_netgrp(spos))
continue;
inside parse_netgrp(). (Lucky for me I happen to have a fairly complex
'live' netgroup database to test this stuff with.)
- Added support for reading netgroups from NIS/YP in addition to the
local /etc/netgroups file. (Note that SunOS and many other systems only
support reading netgroups via NIS, which is a bit odd.)
- Fix Evil Null Pointer Dereferences From Hell (tm) that caused
parse_netgrp() to SEGV when expanding netgroups that include
references to other netgroups. Funny how nobody else noticed this.
This is the first step in implimenting +@netgroup substitution in
getpwent.c and any other places that could use it and don't already
support it (which is probably everywhere).
by heading off possible null pointer dereferences in grscan(). Also
change getgrnam() slightly to properly handle the change: if grscan()
returns an rval of 1 and leaves a '+' in the gr_name field and YP is
enabled, poll the YP group.byname map before giving up. This should
insure that we make every effort to find a match in the local and
YP group databases before bailing out.
commit by bde.
Fix bugs in floating point formatting. The 4.4lite version is similar
to revision 1.3 in old-cvs and is missing all of jtc's fixes in revision
1.4 in old-cvs. Revision 1.2 in ncvs fixed one of the old bugs but
introduced at least one new one (for %.0e).
old-cvs log:
revision 1.4
date: 1993/11/04 19:38:22; author: jtc; state: Exp; lines: +33 -20
My work from NetBSD to make printf() & friends ANSI C compliant.
Fixes several bugs in floating point formatting:
1. Trailing zeros were being stripped with %e format.
2. %g/%G formats incorrect.
3. Lots of other nits.
the copy built from here was overwritten by the other copy and the other
copy was put in library-building command lines twice. ld now objects to
duplicated modules.
from the code in strftime.c . This affects both the library code
and all the commands using it (e.g. date +%s).
Note that %s is not required by ANSI, but we've already got it in 1.1.5.1.
Suggested by: luigi@labinfo.iet.unipi.it (Luigi Rizzo)
in an (unlikely) border case (maxgroups==1 and the user is on
an /etc/group line for the same group and that group only ...).
Now this case is dealt with as before ...
Add a missing apostrophe that suggests inverting the frequency to get
tick size. It read better before because `CLK_TCK' suggests a tick
size although it is actually a frequency.
as an NIS client. The pw_breakout_yp routines that are used to populate the
_pw_passwd structire only do anything if the bits in the pw_fields member
_pw_passwd are cleared. Unfortunately, we can get into a state where
pw_fields has garbage in it right before the YP lookup functions are
called, which causes the breakout functions to screw up in a big way.
Here's how to duplicate the problem:
- Configure FreeBSD as an NIS client
- Log in as a user who's password database records reside only in
the NIS passwd maps.
- Type ps -aux
Result: your processes appear to be owned by 'root' or 'deamon.'
/bin/ls can exhibit the same problem.
The reason this happens:
- When ps(1) needs to match a username to a UID, it calls getpwuid().
- root is in the local password file, so getpwuid() calls __hashpw()
and __hashpw() populates the _pw_passwd struct, including the pw_fields
member. This happens before NIS lookups take place because, by coincidence,
ps(1) tends to display processes owned by root before it happens upon
a proccess owned by you.
- When your UID comes up, __hashpw() fails to find your entry in the
local password database, so it bails out, BUT THE BITS IN THE pw_fields
STRUCTURE OF _pw_passwd ARE NEVER CLEARED AND STILL CONTAIN INFORMATION
FROM THE PREVIOUS CALL TO __hash_pw()!!
- If we have NIS enabled, the NIS lookup functions are called.
- The pw_breakout_yp routines see that the pw_fields bits are set and
decline to place the data retrieved from the NIS passwd maps into the
_pw_passwd structure.
- getpwuid() returns the results of the last __hashpw() lookup instead
of the valid NIS data.
- Hijinxs ensue when user_from_uid() caches this bogus information and
starts handing out the wrong usernames.
AAAARRRRRRRRRGGGGGGHHHHHHHHHH!!!
*Please* don't tell me I'm the only person to have noticed this.
Fixed by having __hashpw() check the state of pw_fields just before
bailing out on a failed lookup and clearing away any leftover garbage.
What a fun way to spend an afternoon.
- FreeBSD's NIS server can supply a master.passwd map, which has
more fields in it than a standard passwd map, so we need a
_master_pw_breakout() fuction.
- When doing passwd map lookups, look for master.passwd.* by attempting
a _yp_first() on master.passwd.byname. If it exists, we're being served
by a FreeBSD NIS server and we should use this map.
- If we aren't the superuser, retrieve only the standard passwd maps.
If we're being served by a FreeBSD system, then the passwd map has
no passwords in it, and it won't serve us the master.passwd map unless
we're superuser anyway.
There's a small speed hit for the superuser inherent in the check for
the master.passwd map, but this lets us dynamically decide what to do
rather than rely on a non-standard config file somewhere. Since all
of this is bypassed for normal users, they shouldn't notice the
difference.
1) Changed LIB_SCCS and SYSLIB_SCCS to LIB_RCS and SYSLIB_RCS.
2) Changed sccsid[] variables to rcsid[]
3) Moved all RCSID strings into .text
4) Converted all SCCSID's to RCS $Id$'s
5) Added missing $Id$'s after copyright.
