_gr_breakout_yp(): if we encounter a NULL pointer generated as the
result of a badly formatted NIS passwd entry (e.g. missing fields),
we punt and return an error code, thereby silently skipping the
bad entry.
last night:
_gr_breakout_yp() doesn't check for badly formatted NIS group entries.
For example, a bogus entry like this:
bootp::user1,user2,user3
will lead to a null pointer dereference and a SEGV (note that the GID
field is missing -- this results in one of the strsep(&result, ":")
returning NULL). The symtpom of this problem is programs dumping
core left and right the moment you add a + entry to /etc/group.
Note that while this is similar to an earlier bug, it's caused by a
different set of circumstances.
The fix is to check for the NULL pointers and have _gr_breakout_yp()
punt and return a failure code if it catches one. This is more or
less the behavior of SunOS: if a bad NIS group entry is encountered,
it's silently ignored. I don't think our standard (non-NIS) group
parsing code behaves the same way. It doesn't crash though, so I'm
citing the 'it ain't broken, don't fix it' rule and leaving it alone.
I'll probably have to add similar checks to _pw_breakout_yp() in
getpwent.c to ward off the same problems. It's rare that bad NIS
map entries like this occur, but we should handle them gracefully
when they do.
'cycle in netgroup check too greedy').
PR #508 is apparently due to an inconsistency in the way the 4.4BSD
netgroup code deals with bad netgroups. When 4.4BSD code encounters
a badly formed netgroup entry (e.g. (somehost,-somedomain), which,
because of the missing comma between the '-' and 'somedomain,' has
only 2 fields instead of 3), it generates an error message and
then bails out without doing any more processing on the netgroup
containing the bad entry. Conversely, every other *NIX in the world
that usees netgroups just tries to parse the entry as best it can
and then silently continues on its way.
The result is that two bad things happen: 1) we ignore other valid entries
within the netgroup containing the bogus entry, which prevents
us from interoperating with other systems that don't behave this way,
and 2) by printing an error to stderr from inside libc, we hose certain
programs, in this case rlogind. In the problem report, Bill Fenner
noted that the 'B' from 'Bad' was missing, and that rlogind exited
immediately after generating the error. The missing 'B' is apparently
not caused by any problem in getnetgrent.c; more likely it's getting
swallowed up by rlogind somehow, and the error message itself causes
rlogind to become confused. I was able to duplicate this problem and
discovered that running a simple test program on my FreeBSD system
resulted in a properly formatted (if confusing) error, whereas triggering
the error by trying to rlogin to the machine yielded the missing 'B'
problem.
Anyway, the fixes for this are as follows:
- The error message has been reformatted so that it prints out more useful
information (e.g. Bad entry (somehost,-somedomain) in netgroup "foo").
We check for NULL entries so that we don't print '(null)' anymore too. :)
- Rearranged things in parse_netgrp() so that we make a best guess at
what bad entries are supposed to look like and then continue processing
instead of bailing out.
- Even though the error message has been cleaned up, it's wrapped inside
a #ifdef DEBUG. This way we match the behavior of other systems. Since we
now handle the error condition better anyway, this error message becomes
less important.
PR #507 is another case of inconsistency. The code that handles
duplicate/circular netgroup entries isn't really 'too greedy; -- it's
just too noisy. If you have a netgroup containing duplicate entries,
the code actually does the right thing, but it also generates an error
message. As with the 'Bad netgroup' message, spewing this out from
inside libc can also hose certain programs (like rlogind). Again, no
other system generates an error message in this case.
The only change here is to hide the error message inside an #ifdef DEBUG.
Like the other message, it's largely superfluous since the code handles
the condition correctly.
Note that PR #510 (+@netgroup host matching in /etc/hosts.equiv) is still
being investigated. I haven't been able to duplicate it myself, and I
strongly suspect it to be a configuration problem of some kind. However,
I'm leaving all three PRs open until I get 510 resolved just for the
sake of paranoia.
ypbind.c:
Make fewer assumtions about the state of the dom_alive and dom_broadcasting
flags in roc_received().
If select() fails, use syslog() to report the error rather than perror().
Check that all our malloc()s succeed. Report malloc() failure in
ypbindproc_setdom_2() to callers.
yplib.c:
Use #defined constants in ypbinderr_string() rather than hard-coded values.
Remove bogus targets.
Allocate partition letters as follows:
lowest offset "flags & CHUNK_IS_ROOT" gets 'a',
lowest offset "subtype==FS_SWAP" gets 'b'
the rest is allocated in offset order from this sequence "defghab".
This will generally make sense.
Added rules to complain if more than one CHUNK_IS_ROOT or more than one
FS_SWAP per FreeBSD chunk.
Set CHUNK_IS_ROOT on the 'a' partition in Open_Disk.
Run Fixup_Names in Open_Disk.
