[RFC] Fix netgroups handling

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

I believe there are several problems in netgroups handling
(setnetgrent/getnetgrent*/endnetgrent/innetgr).
1) data/data_size/cursor/position __netgrent fields are private to the
   service.  From what I understand, there needs to be always at most one service
   live for each __netgrent object.  But we should never allow for one
   service to cleanup after a different service, as it doesn't understand
   how it uses the fields internally.  Say the call internal_endnetgrent
   in NIS or NIS+'s setgrent hook if the fields were previously allocated
   by NIS+ resp. files/NIS will do bad things.
2) using setup/__nss_lookup/__nss_next for hooks other than setgrent
   seems to be wrong to me.  These functions (might) modify __netgrent's
   nip field, but that means that data populated by one service's
   setnetgrent would be interpreted by a different service's
   endnetgrent or getnetgrent_r hook
3) __internal_setnetgrent_reuse call in __internal_getnetgrent_r
   (when some netgroup contains name of another netgroup) might be
   provided by different service.
   Say /etc/netgroup containing
   foo (host1,user1,) bar
   and say NIS+
   bar (host2,user2,)
   But in that case we need to look up a different function, reusing
   the one from last service might be wrong.
4) if (result->cursor == NULL)
     return NSS_STATUS_NOTFOUND;
   in _nss_nis_getnetgrent_r is redundant IMHO, as _nss_netgroup_parseline
   does the same check at the beginning.

The following (just compile tested) patch assumes that only
NSS_STATUS_SUCCESS returning setgrent hooks modify
data/data_size/cursor/position and in that case will call the endnetgrent
hook before switching to another service or another netgroup
and uses just __nss_lookup_function to look up endnetgrent/getnetgrent_r
hooks.

2005-09-09  Jakub Jelinek  <jakub@redhat.com>

	* inet/getnetgrent_r.c: Include assert.
	(setup): Remove FUNC_NAME and ALL arguments, assume they are always
	"setnetgrent" and 1.
	(endnetgrent_hook): New function.
	(internal_endnetgrent): Use it.
	(__internal_setnetgrent_reuse): Use it.  Adjust setup caller.
	If status is NSS_STATUS_SUCCESS, yet action is continue, call
	endnetgrent hook.
	(internal_getnetgrent_r): Use __nss_lookup_function rather than
	setup.  Recompute getfct pointer after successful
	__internal_setnetgrent_reuse.  Don't use __nss_next.
	(innetgr): Use __nss_lookup_function instead of __nss_lookup.
	Adjust setup caller.
	* nss/nss_files/files-netgrp.c (_nss_files_endnetgrent): Always clear
	data_size and cursor.  Add libnss_files_hidden_proto and
	libnss_files_hidden_def.
	(_nss_files_setnetgrent): Call _nss_files_endnetgrent on failure.
	* nis/nss_nis/nis-netgrp.c (internal_endnetgrent): Always clear
	data_size and cursor.
	(_nss_nis_setnetgrent): Don't call internal_endnetgrent.
	(_nss_nis_getnetgrent_r): Remove result->cursor == NULL handling.
	* nis/nss_nisplus/nisplus-netgrp.c (internal_endnetgrent): Always clear
	data_size and position.
	(_nss_nisplus_setnetgrent): Don't call internal_endnetgrent.

--- libc/inet/getnetgrent_r.c.jj	2004-08-14 18:18:30.000000000 +0200
+++ libc/inet/getnetgrent_r.c	2005-09-09 15:22:13.000000000 +0200
@@ -1,4 +1,5 @@
-/* Copyright (C) 1996,1997,1998,1999,2002,2004 Free Software Foundation, Inc.
+/* Copyright (C) 1996, 1997, 1998, 1999, 2002, 2004, 2005
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -16,6 +17,7 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+#include <assert.h>
 #include <bits/libc-lock.h>
 #include <errno.h>
 #include <netdb.h>
@@ -33,15 +35,13 @@ __libc_lock_define_initialized (static, 
 static struct __netgrent dataset;
 
 /* The lookup function for the first entry of this service.  */
-extern int __nss_netgroup_lookup (service_user **nip, const char *name,
+extern int __nss_netgroup_lookup (service_user **nipp, const char *name,
 				  void **fctp) internal_function;
 
-
-/* Set up NIP to run through the services.  If ALL is zero, use NIP's
-   current location if it's not nil.  Return nonzero if there are no
+/* Set up NIP to run through the services.  Return nonzero if there are no
    services (left).  */
 static enum nss_status
-setup (void **fctp, const char *func_name, int all, service_user **nipp)
+setup (void **fctp, service_user **nipp)
 {
   /* Remember the first service_entry, it's always the same.  */
   static service_user *startp;
@@ -51,7 +51,7 @@ setup (void **fctp, const char *func_nam
     {
       /* Executing this more than once at the same time must yield the
 	 same result every time.  So we need no locking.  */
-      no_more = __nss_netgroup_lookup (nipp, func_name, fctp);
+      no_more = __nss_netgroup_lookup (nipp, "setnetgrent", fctp);
       startp = no_more ? (service_user *) -1 : *nipp;
     }
   else if (startp == (service_user *) -1)
@@ -59,11 +59,10 @@ setup (void **fctp, const char *func_nam
     return 1;
   else
     {
-      if (all || *nipp == NULL)
-	/* Reset to the beginning of the service list.  */
-	*nipp = startp;
+      /* Reset to the beginning of the service list.  */
+      *nipp = startp;
       /* Look up the first function.  */
-      no_more = __nss_lookup (nipp, func_name, fctp);
+      no_more = __nss_lookup (nipp, "setnetgrent", fctp);
     }
   return no_more;
 }
@@ -87,6 +86,20 @@ free_memory (struct __netgrent *data)
     }
 }
 
+static void
+endnetgrent_hook (struct __netgrent *datap)
+{
+  enum nss_status (*endfct) (struct __netgrent *);
+
+  if (datap->nip == NULL)
+    return;
+
+  endfct = __nss_lookup_function (datap->nip, "endnetgrent");
+  if (endfct != NULL)
+    (void) (*endfct) (datap);
+  datap->nip = NULL;
+}
+
 static int
 internal_function
 __internal_setnetgrent_reuse (const char *group, struct __netgrent *datap,
@@ -100,14 +113,29 @@ __internal_setnetgrent_reuse (const char
   enum nss_status status = NSS_STATUS_UNAVAIL;
   struct name_list *new_elem;
 
+  /* Free data from previous service.  */
+  endnetgrent_hook (datap);
+
   /* Cycle through all the services and run their setnetgrent functions.  */
-  int no_more = setup (&fct.ptr, "setnetgrent", 1, &datap->nip);
+  int no_more = setup (&fct.ptr, &datap->nip);
   while (! no_more)
     {
+      assert (datap->data == NULL);
+
       /* Ignore status, we force check in `__nss_next'.  */
       status = (*fct.f) (group, datap);
 
+      service_user *old_nip = datap->nip;
       no_more = __nss_next (&datap->nip, "setnetgrent", &fct.ptr, status, 0);
+
+      if (status == NSS_STATUS_SUCCESS && ! no_more)
+	{
+	  enum nss_status (*endfct) (struct __netgrent *);
+
+	  endfct = __nss_lookup_function (old_nip, "endnetgrent");
+	  if (endfct != NULL)
+	    (void) (*endfct) (datap);
+	}
     }
 
   /* Add the current group to the list of known groups.  */
@@ -157,34 +185,13 @@ setnetgrent (const char *group)
   return result;
 }
 
-
 void internal_endnetgrent (struct __netgrent *datap);
 libc_hidden_proto (internal_endnetgrent)
 
 void
 internal_endnetgrent (struct __netgrent *datap)
 {
-  service_user *old_nip;
-  union
-  {
-    enum nss_status (*f) (struct __netgrent *);
-    void *ptr;
-  } fct;
-
-  /* Remember which was the last used service.  */
-  old_nip = datap->nip;
-
-  /* Cycle through all the services and run their endnetgrent functions.  */
-  int no_more = setup (&fct.ptr, "endnetgrent", 1, &datap->nip);
-  while (! no_more)
-    {
-      /* Ignore status, we force check in `__nss_next'.  */
-      (void) (*fct.f) (datap);
-
-      no_more = (datap->nip == old_nip
-		 || __nss_next (&datap->nip, "endnetgrent", &fct.ptr, 0, 1));
-    }
-
+  endnetgrent_hook (datap);
   /* Now free list of all netgroup names from last run.  */
   free_memory (datap);
 }
@@ -213,11 +220,7 @@ internal_getnetgrent_r (char **hostp, ch
 			  struct __netgrent *datap,
 			  char *buffer, size_t buflen, int *errnop)
 {
-  union
-  {
-    enum nss_status (*f) (struct __netgrent *, char *, size_t, int *);
-    void *ptr;
-  } fct;
+  enum nss_status (*fct) (struct __netgrent *, char *, size_t, int *);
 
   /* Initialize status to return if no more functions are found.  */
   enum nss_status status = NSS_STATUS_NOTFOUND;
@@ -225,10 +228,12 @@ internal_getnetgrent_r (char **hostp, ch
   /* Run through available functions, starting with the same function last
      run.  We will repeat each function as long as it succeeds, and then go
      on to the next service action.  */
-  int no_more = setup (&fct.ptr, "getnetgrent_r", 0, &datap->nip);
+  int no_more = (datap->nip == NULL
+		 || (fct = __nss_lookup_function (datap->nip, "getnetgrent_r"))
+		    == NULL);
   while (! no_more)
     {
-      status = (*fct.f) (datap, buffer, buflen, &errno);
+      status = (*fct) (datap, buffer, buflen, &errno);
 
       if (status == NSS_STATUS_RETURN)
 	{
@@ -246,8 +251,12 @@ internal_getnetgrent_r (char **hostp, ch
 						    datap, errnop);
 	    }
 
-	  if (found)
-	    continue;
+	  if (found && datap->nip != NULL)
+	    {
+	      fct = __nss_lookup_function (datap->nip, "getnetgrent_r");
+	      if (fct != NULL)
+		continue;
+	    }
 	}
       else if (status == NSS_STATUS_SUCCESS && datap->type == group_val)
 	{
@@ -279,7 +288,7 @@ internal_getnetgrent_r (char **hostp, ch
 	    }
 	}
 
-      no_more = __nss_next (&datap->nip, "getnetgrent_r", &fct.ptr, status, 0);
+      break;
     }
 
   if (status == NSS_STATUS_SUCCESS)
@@ -322,16 +331,8 @@ innetgr (const char *netgroup, const cha
     int (*f) (const char *, struct __netgrent *);
     void *ptr;
   } setfct;
-  union
-  {
-    void (*f) (struct __netgrent *);
-    void *ptr;
-  } endfct;
-  union
-  {
-    int (*f) (struct __netgrent *, char *, size_t, int *);
-    void *ptr;
-  } getfct;
+  void (*endfct) (struct __netgrent *);
+  int (*getfct) (struct __netgrent *, char *, size_t, int *);
   struct __netgrent entry;
   int result = 0;
   const char *current_group = netgroup;
@@ -345,18 +346,21 @@ innetgr (const char *netgroup, const cha
      the work during one walk through the service list.  */
   while (1)
     {
-      int no_more = setup (&setfct.ptr, "setnetgrent", 1, &entry.nip);
+      int no_more = setup (&setfct.ptr, &entry.nip);
       while (! no_more)
 	{
+	  assert (entry.data == NULL);
+
 	  /* Open netgroup.  */
 	  enum nss_status status = (*setfct.f) (current_group, &entry);
 
 	  if (status == NSS_STATUS_SUCCESS
-	      && __nss_lookup (&entry.nip, "getnetgrent_r", &getfct.ptr) == 0)
+	      && (getfct = __nss_lookup_function (entry.nip, "getnetgrent_r"))
+		 != NULL)
 	    {
 	      char buffer[1024];
 
-	      while ((*getfct.f) (&entry, buffer, sizeof buffer, &errno)
+	      while ((*getfct) (&entry, buffer, sizeof buffer, &errno)
 		     == NSS_STATUS_SUCCESS)
 		{
 		  if (entry.type == group_val)
@@ -414,8 +418,9 @@ innetgr (const char *netgroup, const cha
 	    }
 
 	  /* Free all resources of the service.  */
-	  if (__nss_lookup (&entry.nip, "endnetgrent", &endfct.ptr) == 0)
-	    (*endfct.f) (&entry);
+	  endfct = __nss_lookup_function (entry.nip, "endnetgrent");
+	  if (endfct != NULL)
+	    (*endfct) (&entry);
 
 	  /* Look for the next service.  */
 	  no_more = __nss_next (&entry.nip, "setnetgrent",
--- libc/nis/nss_nisplus/nisplus-netgrp.c.jj	2004-12-13 09:36:17.000000000 +0100
+++ libc/nis/nss_nisplus/nisplus-netgrp.c	2005-09-09 13:42:45.000000000 +0200
@@ -1,4 +1,4 @@
-/* Copyright (C) 1997, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 1997, 2003, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1997.
 
@@ -142,12 +142,10 @@ static void
 internal_endnetgrent (struct __netgrent *netgrp)
 {
   if (netgrp->data != NULL)
-    {
-      nis_freeresult ((nis_result *) netgrp->data);
-      netgrp->data = NULL;
-      netgrp->data_size = 0;
-      netgrp->position = 0;
-    }
+    nis_freeresult ((nis_result *) netgrp->data);
+  netgrp->data = NULL;
+  netgrp->data_size = 0;
+  netgrp->position = 0;
 }
 
 enum nss_status
@@ -161,8 +159,6 @@ _nss_nisplus_setnetgrent (const char *gr
 
   status = NSS_STATUS_SUCCESS;
 
-  internal_endnetgrent (netgrp);
-
   sprintf (buf, "[name=%s],netgroup.org_dir", group);
 
   netgrp->data = (char *) nis_list (buf, EXPAND_NAME, NULL, NULL);
--- libc/nis/nss_nis/nis-netgrp.c.jj	2005-08-23 12:00:37.000000000 +0200
+++ libc/nis/nss_nis/nis-netgrp.c	2005-09-09 13:40:34.000000000 +0200
@@ -41,13 +41,10 @@ _nss_netgroup_parseline (char **cursor, 
 static void
 internal_nis_endnetgrent (struct __netgrent *netgrp)
 {
-  if (netgrp->data != NULL)
-    {
-      free (netgrp->data);
-      netgrp->data = NULL;
-      netgrp->data_size = 0;
-      netgrp->cursor = NULL;
-    }
+  free (netgrp->data);
+  netgrp->data = NULL;
+  netgrp->data_size = 0;
+  netgrp->cursor = NULL;
 }
 
 enum nss_status
@@ -65,8 +62,6 @@ _nss_nis_setnetgrent (const char *group,
   if (yp_get_default_domain (&domain))
     return NSS_STATUS_UNAVAIL;
 
-  internal_nis_endnetgrent (netgrp);
-
   status = yperr2nss (yp_match (domain, "netgroup", group, strlen (group),
 				&netgrp->data, &len));
   if (status == NSS_STATUS_SUCCESS)
@@ -99,9 +94,6 @@ enum nss_status
 _nss_nis_getnetgrent_r (struct __netgrent *result, char *buffer, size_t buflen,
 			int *errnop)
 {
-  if (result->cursor == NULL)
-    return NSS_STATUS_NOTFOUND;
-
   return _nss_netgroup_parseline (&result->cursor, result, buffer, buflen,
 				  errnop);
 }
--- libc/nss/nss_files/files-netgrp.c.jj	2004-11-23 21:42:29.000000000 +0100
+++ libc/nss/nss_files/files-netgrp.c	2005-09-09 13:35:31.000000000 +0200
@@ -1,5 +1,5 @@
 /* Netgroup file parser in nss_files modules.
-   Copyright (C) 1996, 1997, 2000, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997, 2000, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
 
@@ -29,6 +29,7 @@
 
 #define DATAFILE	"/etc/netgroup"
 
+libnss_files_hidden_proto (_nss_files_endnetgrent)
 
 #define EXPAND(needed)							      \
   do									      \
@@ -140,6 +141,9 @@ _nss_files_setnetgrent (const char *grou
       /* We don't need the file and the line buffer anymore.  */
       free (line);
       fclose (fp);
+
+      if (status != NSS_STATUS_SUCCESS)
+	_nss_files_endnetgrent (result);
     }
 
   return status;
@@ -150,16 +154,13 @@ int
 _nss_files_endnetgrent (struct __netgrent *result)
 {
   /* Free allocated memory for data if some is present.  */
-  if (result->data != NULL)
-    {
-      free (result->data);
-      result->data = NULL;
-      result->data_size = 0;
-      result->cursor = NULL;
-    }
-
+  free (result->data);
+  result->data = NULL;
+  result->data_size = 0;
+  result->cursor = NULL;
   return NSS_STATUS_SUCCESS;
 }
+libnss_files_hidden_def (_nss_files_endnetgrent)
 
 static char *
 strip_whitespace (char *str)

	Jakub