[SSSD] [PATCH] LDAP: sdap_auth_send() properly initialize ppolicy

Sumit Bose sbose at redhat.com
Fri Jun 27 09:02:26 UTC 2014


On Fri, Jun 27, 2014 at 10:22:23AM +0200, Jakub Hrozek wrote:
> On Thu, Jun 26, 2014 at 02:23:48PM +0200, Sumit Bose wrote:
> > On Thu, Jun 26, 2014 at 01:39:24PM +0200, Lukas Slebodnik wrote:
> > > On (26/06/14 13:00), Sumit Bose wrote:
> > > >Hi,
> > > >
> > > >I found this while debugging timeout issues during authentication.
> > > >
> > > >bye,
> > > >Sumit
> > > 
> > > >From 03879293f434cf2aaa6db9ead75830ba4a7050a7 Mon Sep 17 00:00:00 2001
> > > >From: Sumit Bose <sbose at redhat.com>
> > > >Date: Thu, 26 Jun 2014 11:59:55 +0200
> > > >Subject: [PATCH] LDAP: sdap_auth_send() properly initialize ppolicy
> > > >
> > > >In case of an error ppolicy might not be set to NULL and
> > > >auth_bind_user_done() might show some unexpected debug messages.
> > > >---
> > > > src/providers/ldap/sdap_async_connection.c | 2 ++
> > > > 1 file changed, 2 insertions(+)
> > > >
> > > >diff --git a/src/providers/ldap/sdap_async_connection.c b/src/providers/ldap/sdap_async_connection.c
> > > >index a1f78c0..7407ae7 100644
> > > >--- a/src/providers/ldap/sdap_async_connection.c
> > > >+++ b/src/providers/ldap/sdap_async_connection.c
> > > >@@ -1282,6 +1282,8 @@ struct tevent_req *sdap_auth_send(TALLOC_CTX *memctx,
> > > >     req = tevent_req_create(memctx, &state, struct sdap_auth_state);
> > > >     if (!req) return NULL;
> > > > 
> > > >+    state->ppolicy = NULL;
> > > >+
> > > >     if (sasl_mech) {
> > > >         state->is_sasl = true;
> > > >         subreq = sasl_bind_send(state, ev, sh, sasl_mech, sasl_user, NULL);
> > > This would solve problem.
> > > 
> > > In my opinion, it would be better to solve in in function auth_bind_user_done
> > > 
> > > src/providers/ldap/ldap_auth.c:
> > > errno_t sdap_auth_recv(struct tevent_req *req,
> > >     //snip
> > >    826         ret = sdap_auth_recv(subreq, state, &ppolicy)
> > >    827         talloc_zfree(subreq);
> > >    828         if (ppolicy != NULL) {
> > >                    variable ret should be tested instead of ppolicy
> > >    829             DEBUG(SSSDBG_TRACE_ALL,"Found ppolicy data, "
> > > 
> > > BTW function sdap_auth_recv looks supspicious as well.
> > > 
> > > src/providers/ldap/sdap_async_connection.c:
> > > 1366 errno_t sdap_auth_recv(struct tevent_req *req,
> > > 1367                        TALLOC_CTX *memctx,
> > > 1368                        struct sdap_ppolicy_data **ppolicy)
> > > 1369 {
> > > 1370     struct sdap_auth_state *state = tevent_req_data(req,
> > > 1371                                                  struct sdap_auth_state);
> > > 1372
> > > 1373     if (ppolicy != NULL) {
> > > 1374         *ppolicy = talloc_steal(memctx, state->ppolicy);
> > > 1375     }
> > > 1376
> > > 1377     TEVENT_REQ_RETURN_ON_ERROR(req);
> > >          this macro used to be called before talloc_steal in other recv
> > >          functions.
> > > 
> > > 1378
> > > 1379     return EOK;
> > > 1380 }
> > > 
> > 
> > Thank you, these are good points. Nevertheless I think it is a good idea
> > and common practice to initialize the members of a state ...
> > 
> > > It is possible I overlooked something.
> > 
> > ... to make other usage not fail.
> > 
> > New version attached.
> > 
> > bye,
> > Sumit
> > > 
> > > LS
> > > _______________________________________________
> > > sssd-devel mailing list
> > > sssd-devel at lists.fedorahosted.org
> > > https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
> 
> > From 52939ac7fe32e52dac9368f8bb1f7f1a337fdc87 Mon Sep 17 00:00:00 2001
> > From: Sumit Bose <sbose at redhat.com>
> > Date: Thu, 26 Jun 2014 11:59:55 +0200
> > Subject: [PATCH] LDAP: sdap_auth_send() properly initialize ppolicy
> > 
> > In case of an error ppolicy might not be set to NULL and
> > auth_bind_user_done() might show some unexpected debug messages.
> > 
> > Additionally this patch fixes the usage of ppolicy in case of an error.
> > ---
> >  src/providers/ldap/ldap_auth.c             | 12 ++++++------
> >  src/providers/ldap/sdap_async_connection.c |  6 ++++--
> >  2 files changed, 10 insertions(+), 8 deletions(-)
> > 
> > diff --git a/src/providers/ldap/ldap_auth.c b/src/providers/ldap/ldap_auth.c
> > index 40f297c..20fa23a 100644
> > --- a/src/providers/ldap/ldap_auth.c
> > +++ b/src/providers/ldap/ldap_auth.c
> > @@ -825,14 +825,14 @@ static void auth_bind_user_done(struct tevent_req *subreq)
> >  
> >      ret = sdap_auth_recv(subreq, state, &ppolicy);
> >      talloc_zfree(subreq);
> > -    if (ppolicy != NULL) {
> > -        DEBUG(SSSDBG_TRACE_ALL,"Found ppolicy data, "
> > -                 "assuming LDAP password policies are active.\n");
> > -        state->pw_expire_type = PWEXPIRE_LDAP_PASSWORD_POLICY;
> > -        state->pw_expire_data = ppolicy;
> > -    }
> >      switch (ret) {
> >      case EOK:
> > +        if (ppolicy != NULL) {
> > +            DEBUG(SSSDBG_TRACE_ALL,"Found ppolicy data, "
> > +                     "assuming LDAP password policies are active.\n");
> > +            state->pw_expire_type = PWEXPIRE_LDAP_PASSWORD_POLICY;
> > +            state->pw_expire_data = ppolicy;
> > +        }
> >          break;
> >      case ETIMEDOUT:
> >      case ERR_NETWORK_IO:
> > diff --git a/src/providers/ldap/sdap_async_connection.c b/src/providers/ldap/sdap_async_connection.c
> > index a1f78c0..ade9879 100644
> > --- a/src/providers/ldap/sdap_async_connection.c
> > +++ b/src/providers/ldap/sdap_async_connection.c
> > @@ -1282,6 +1282,8 @@ struct tevent_req *sdap_auth_send(TALLOC_CTX *memctx,
> >      req = tevent_req_create(memctx, &state, struct sdap_auth_state);
> >      if (!req) return NULL;
> >  
> > +    state->ppolicy = NULL;
> > +
> 
> I wonder if the problem you saw was really caused by this
> initialization? The way I read tevent_req_create code, the memory should
> already be set to NULL:
> 
> 80         data = talloc_zero_size(req, data_size);
> 81         if (data == NULL) {
> 82                 talloc_free(req);
> 83                 return NULL;
> 84         }
> 85         talloc_set_name_const(data, type);
> 86 
> 
> Please note I'm not against this patch, especially the
> TEVENT_REQ_RETURN_ON_ERROR is correct, I just wonder if we're maybe not
> seeing the right cause..

Thank you for the hint. I always thought that the state is not
initialized because I remember a discussion long time ago that it is not
done on purpose for performance reasons. But it looks that libtevent does
initialize this since about 5 years ago.

I checked the usage of ppolicy again and so far found no reason why it
should be set in the case of a timeout. I will continue investigating.

bye,
Sumit

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