Re: psql with GSS can crash - Mailing list pgsql-hackers
From | Magnus Hagander |
---|---|
Subject | Re: psql with GSS can crash |
Date | |
Msg-id | 9837222c1003080203sf031cb7v6c5f7821a7f52494@mail.gmail.com Whole thread Raw |
In response to | Re: psql with GSS can crash (Zdenek Kotala <Zdenek.Kotala@Sun.COM>) |
List | pgsql-hackers |
2010/3/7 Zdenek Kotala <Zdenek.Kotala@sun.com>: > Magnus Hagander píše v po 01. 03. 2010 v 16:55 +0100: >> 2010/3/1 Zdenek Kotala <Zdenek.Kotala@sun.com>: >> > Magnus Hagander píše v čt 25. 02. 2010 v 15:17 +0100: >> >> On Thu, Feb 25, 2010 at 15:04, Zdenek Kotala <Zdenek.Kotala@sun.com> wrote: >> >> > Hi all, >> >> > >> >> > I got following stack: >> >> > >> >> > fffffd7ffed14b70 strlen () + 40 >> >> > fffffd7ffed71665 snprintf () + e5 >> >> > fffffd7fff36d088 pg_GSS_startup () + 88 >> >> > fffffd7fff36d43a pg_fe_sendauth () + 15a >> >> > fffffd7fff36e557 PQconnectPoll () + 3b7 >> >> > fffffd7fff36e152 connectDBComplete () + a2 >> >> > fffffd7fff36dc32 PQsetdbLogin () + 1b2 >> >> > 000000000041e96d main () + 30d >> >> > 000000000041302c ???????? () >> >> > >> >> > It seems that connection is not fully configured and krbsrvname or pghost is >> >> > not filled. Following code in fe-auth.c pg_GSS_startup() causes a crash: >> >> > >> >> > 440 maxlen = NI_MAXHOST + strlen(conn->krbsrvname) + 2; >> >> > 441 temp_gbuf.value = (char *) malloc(maxlen); >> >> > 442 snprintf(temp_gbuf.value, maxlen, "%s@%s", >> >> > 443 conn->krbsrvname, conn->pghost); >> >> > 444 temp_gbuf.length = strlen(temp_gbuf.value); >> >> > >> >> > And following code in fe-connect.c fillPGconn() fill NULL value. >> >> > >> >> > 571 tmp = conninfo_getval(connOptions, "krbsrvname"); >> >> > 572 conn->krbsrvname = tmp ? strdup(tmp) : NULL; >> >> > >> >> > I think that pg_GSS_startup should sanity the input. >> >> >> >> How did you get NULL in there? :-) >> >> There's a default set for that one that's PG_KRB_SRVNAM, so it really >> >> should never come out as NULL, I think... >> > >> > Yeah, you are right. conn->krbsrvname is "postgres" and conn->pghost is >> > null >> >> Ah, good. We should defentd against that then. >> >> >> >> As for pghost, that certainly seems to be a bug. We check that one in >> >> krb5 and SSPI, but for some reason we seem to be missing it in GSSAPI. >> > >> > Yes. The check should be in GSSAPI too. >> > >> > However what I see in pg_hba.conf is following line: >> > >> > local all all gss >> > >> > Gss is used on local unix socket which probably cause a problem that >> > conn->pghost is not filled when psql tries to connect. >> >> So there are really two errors - because we should disallow that. >> >> See attached patch - can you confirm it removes the crash with just >> the client side applied, and then that it properly rejects GSS with >> the server side applied as well? > > I tested it, but I cannot reproduce crash because I cannot setup illegal > combination now ;-). I think it is OK. Ok, thanks for testing. I've been unable to break it in my testing as well so - applied, and back-patched. -- Magnus HaganderMe: http://www.hagander.net/Work: http://www.redpill-linpro.com/
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