Re: question on ldap_unbind_ext_s

[Howard Chu <hyc@symas.com>]

Aditham, Radhakrishna wrote:
> Hi,
>
> We have a long running server that tries to get a new LDAP handle if the
> current handle becomes invalid (LDAP_SERVER_DOWN error, etc).
>
> However if I call ldap_unbind_ext_s() on the old handle to release it, it
> hangs with the following stack:
>
> (gdb) bt
>
> #0  0x000000080166935c in read () at read.S:2
>
> #1  0x00000008014748f0 in __read (fd=68, buf=0x803293003, nbytes=5) at
> /.automount/nfs.panwest.panasas.com/root/sb10/hlewis/hlewis-sb10-pioneer-ldap/src/freebsd-c/lib/libthr/thread/thr_syscalls.c:384
>
> #2  0x0000000802c715d2 in sb_stream_read (sbiod=0x8088070d0, buf=0x803293003,
> len=5) at
> /.automount/nfs.panwest.panasas.com/root/sb10/hlewis/hlewis-sb10-pioneer-ldap/src/likewise/openldap/libraries/liblber/sockbuf.c:493
>
> #3  0x0000000802c7207e in sb_debug_read (sbiod=0x803291220, buf=0x803293003,
> len=5) at
> /.automount/nfs.panwest.panasas.com/root/sb10/hlewis/hlewis-sb10-pioneer-ldap/src/likewise/openldap/libraries/liblber/sockbuf.c:827
>
> #4  0x0000000802356971 in tlso_bio_read (b=0x803205400, buf=0x803293003
> "\027\003\001", len=5) at tls_o.c:687
>
> #5  0x000000080252c2df in BIO_read () from /usr/lib/libcrypto.so.1.0.0
>
> #6  0x0000000802eb9f01 in ssl3_read_n () from /usr/lib/libssl.so.1.0.0
>
> #7  0x0000000802eba3ce in ssl3_read_bytes () from /usr/lib/libssl.so.1.0.0
>
> #8  0x0000000802eb67ac in ssl3_shutdown () from /usr/lib/libssl.so.1.0.0
>
> #9  0x0000000802356cf6 in tlso_sb_close (sbiod=0x803291250) at tls_o.c:808
>
> #10 0x0000000802c71253 in ber_int_sb_close (sb=0x803291160) at
> /.automount/nfs.panwest.panasas.com/root/sb10/hlewis/hlewis-sb10-pioneer-ldap/src/likewise/openldap/libraries/liblber/sockbuf.c:383
>
> #11 0x000000080233d625 in ldap_free_connection (ld=0x804c48c00,
> lc=0x8088080f0, force=1, unbind=1) at request.c:769
>
> #12 0x000000080232ffa2 in ldap_ld_free (ld=0x804c48c00, close=1, sctrls=0x0,
> cctrls=0x0) at unbind.c:93
>
> #13 0x000000080232fe8b in ldap_unbind_ext (ld=0x804c48c00, sctrls=0x0,
> cctrls=0x0) at unbind.c:52
>
> #14 0x000000080232fec5 in ldap_unbind_ext_s (ld=0x804c48c00, sctrls=0x0,
> cctrls=0x0) at unbind.c:61
>
> ……
>
> I want to make sure that there are memory leaks etc, hence the attempt to
> release the invalid handle.
>
> Question: What is the best or correct way to release an invalid LDAP handle?

ldap_unbind is the correct way. Looks like a bug in OpenSSL; if the connection 
is gone already it should not be trying to read from it.
> Appreciate any help.
>
> Thanks
>
> R.K. Aditham


--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/