r23244: Fix loop with nscd and NSS recusive calls.

> Here's the problem I hit:
>
> getgrnam("foo") -> nscd -> NSS -> winbindd ->
>   winbindd_passdb.c:nam_to_sid() -> lookup_global_sam_name() ->
>   getgrnam("foo") -> nscd -> ....
>
> This is in the SAMBA_3_0 specifically but in theory could happen
> SAMBA_3_0_25 (or 26) for an unknown group.
>
> The attached patch passes down enough state for the
> name_to_sid() call to be able to determine the originating
> winbindd cmd that came into the parent.  So we can avoid
> making more NSS calls if the original call came in trough NSS
> so we don't deadlock ?  But you should still service
> lookupname() calls which are needed for example when
> doing the token access checks for a "valid groups" from
> smb.conf.
>
> I've got this in testing now.  The problem has shown up with the
> DsProvider on OS X and with nscd on SOlaris and Linux.
(This used to be commit bcc8a3290aaa0d2620e9d391ffbbf65541f6d742)

1 files changed, 4 insertions, 2 deletions

diff --git a/source3/nsswitch/winbindd_async.c b/source3/nsswitch/winbindd_async.c
index b674ef6cee..dbe4ad012b 100644
--- a/source3/nsswitch/winbindd_async.c
+++ b/source3/nsswitch/winbindd_async.c
@@ -952,6 +952,7 @@ void winbindd_lookupname_async(TALLOC_CTX *mem_ctx,
 			       void (*cont)(void *private_data, BOOL success,
 					    const DOM_SID *sid,
 					    enum lsa_SidType type),
+			       enum winbindd_cmd orig_cmd,
 			       void *private_data)
 {
 	struct winbindd_request request;
@@ -966,6 +967,7 @@ void winbindd_lookupname_async(TALLOC_CTX *mem_ctx,
 
 	ZERO_STRUCT(request);
 	request.cmd = WINBINDD_LOOKUPNAME;
+	request.original_cmd = orig_cmd;
 	fstrcpy(request.data.name.dom_name, dom_name);
 	fstrcpy(request.data.name.name, name);
 
@@ -977,7 +979,7 @@ void winbindd_lookupname_async(TALLOC_CTX *mem_ctx,
 
 	s->dom_name = talloc_strdup( s, dom_name );
 	s->name     = talloc_strdup( s, name );
-	s->caller_private_data = private_data;	
+	s->caller_private_data = private_data;
 
 	do_async_domain(mem_ctx, domain, &request, lookupname_recv,
 			(void *)cont, s);
@@ -1012,7 +1014,7 @@ enum winbindd_result winbindd_dual_lookupname(struct winbindd_domain *domain,
 		  name_domain, lp_winbind_separator(), name_user));
 
 	/* Lookup name from DC using lsa_lookup_names() */
-	if (!winbindd_lookup_sid_by_name(state->mem_ctx, domain, name_domain,
+	if (!winbindd_lookup_sid_by_name(state->mem_ctx, state->request.original_cmd, domain, name_domain,
 					 name_user, &sid, &type)) {
 		return WINBINDD_ERROR;
 	}