Implement new mode for NIS passwd.adjunct.byname table.

The passwd.adjunct.byname table will not be used to fill in password fields
in the passwd.byname replies.  Instead it is used to synthesize the
shadow.byname table, should it be missing.  This is a useful mode in some
installations involving Solaris.

5 files changed, 102 insertions, 47 deletions

diff --git a/nis/libnsl.h b/nis/libnsl.h
index c6ceb32..dc15930 100644
--- a/nis/libnsl.h
+++ b/nis/libnsl.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 2005, 2006, 2010 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
@@ -21,6 +21,7 @@
 #define NSS_FLAG_NETID_AUTHORITATIVE	1
 #define NSS_FLAG_SERVICES_AUTHORITATIVE	2
 #define NSS_FLAG_SETENT_BATCH_READ	4
+#define NSS_FLAG_ADJUNCT_AS_SHADOW	8
 
 
 /* Get current set of default flags.  */
diff --git a/nis/nss b/nis/nss
index aab40ab..0ac6774 100644
--- a/nis/nss
+++ b/nis/nss
@@ -1,7 +1,7 @@
 # /etc/default/nss
 # This file can theoretically contain a bunch of customization variables
 # for Name Service Switch in the GNU C library.  For now there are only
-# three variables:
+# four variables:
 #
 # NETID_AUTHORITATIVE
 #   If set to TRUE, the initgroups() function will accept the information
@@ -26,3 +26,12 @@
 #  might result into a network communication with the server to get
 #  the next entry.
 #SETENT_BATCH_READ=TRUE
+#
+# ADJUNCT_AS_SHADOW
+#  If set to TRUE, the passwd routines in the NIS NSS module will not
+#  use the passwd.adjunct.byname tables to fill in the password data
+#  in the passwd structure.  This is a security problem if the NIS
+#  server cannot be trusted to send the passwd.adjuct table only to
+#  privileged clients.  Instead the passwd.adjunct.byname table is
+#  used to synthesize the shadow.byname table if it does not exist.
+#ADJUNCT_AS_SHADOW=TRUE
diff --git a/nis/nss-default.c b/nis/nss-default.c
index 046ddfe..d7a3293 100644
--- a/nis/nss-default.c
+++ b/nis/nss-default.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1996, 2001, 2004, 2006, 2007 Free Software Foundation, Inc.
+/* Copyright (C) 1996,2001,2004,2006,2007,2010 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
@@ -47,7 +47,8 @@ static const struct
 #define STRNLEN(s) s, sizeof (s) - 1
     { STRNLEN ("NETID_AUTHORITATIVE"), NSS_FLAG_NETID_AUTHORITATIVE },
     { STRNLEN ("SERVICES_AUTHORITATIVE"), NSS_FLAG_SERVICES_AUTHORITATIVE },
-    { STRNLEN ("SETENT_BATCH_READ"), NSS_FLAG_SETENT_BATCH_READ }
+    { STRNLEN ("SETENT_BATCH_READ"), NSS_FLAG_SETENT_BATCH_READ },
+    { STRNLEN ("ADJUNCT_AS_SHADOW"), NSS_FLAG_ADJUNCT_AS_SHADOW },
   };
 #define nvars (sizeof (vars) / sizeof (vars[0]))
 
diff --git a/nis/nss_nis/nis-pwd.c b/nis/nss_nis/nis-pwd.c
index fdc7dc9..89de350 100644
--- a/nis/nss_nis/nis-pwd.c
+++ b/nis/nss_nis/nis-pwd.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1996-1998,2001-2003,2006,2009 Free Software Foundation, Inc.
+/* Copyright (C) 1996-1998,2001-2003,2006,2009,2010
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.
 
@@ -39,7 +40,7 @@
 /* Protect global state against multiple changers */
 __libc_lock_define_initialized (static, lock)
 
-static bool_t new_start = 1;
+static bool new_start = true;
 static char *oldkey;
 static int oldkeylen;
 static intern_t intern;
@@ -108,13 +109,10 @@ _nis_saveit (int instatus, char *inkey, int inkeylen, char *inval,
 static void
 internal_nis_endpwent (void)
 {
-  new_start = 1;
-  if (oldkey != NULL)
-    {
-      free (oldkey);
-      oldkey = NULL;
-      oldkeylen = 0;
-    }
+  new_start = true;
+  free (oldkey);
+  oldkey = NULL;
+  oldkeylen = 0;
 
   struct response_t *curr = intern.start;
 
@@ -264,18 +262,21 @@ internal_nis_getpwent_r (struct passwd *pwd, char *buffer, size_t buflen,
 	}
 
       /* Check for adjunct style secret passwords.  They can be
-	 recognized by a password starting with "##".  */
+	 recognized by a password starting with "##".  We do not use
+	 it if the passwd.adjunct.byname table is supposed to be used
+	 as a shadow.byname replacement.  */
       char *p = strchr (result, ':');
       size_t namelen;
       char *result2;
       int len2;
-      if (p != NULL	/* This better should be true in all cases.  */
+      if ((_nsl_default_nss () & NSS_FLAG_ADJUNCT_AS_SHADOW) == 0
+	  && p != NULL	/* This better should be true in all cases.  */
 	  && p[1] == '#' && p[2] == '#'
 	  && (namelen = p - result,
 	      yp_match (domain, "passwd.adjunct.byname", result, namelen,
 			&result2, &len2)) == YPERR_SUCCESS)
 	{
-	  /* We found a passwd.adjunct entry.  Merge encrypted
+	  /* We found a passwd.adjunct.byname entry.  Merge encrypted
 	     password therein into original result.  */
 	  char *encrypted = strchr (result2, ':');
 	  char *endp;
@@ -325,7 +326,7 @@ internal_nis_getpwent_r (struct passwd *pwd, char *buffer, size_t buflen,
 	}
 
       while (isspace (*p))
-        ++p;
+	++p;
       if (!batch_read)
 	free (result);
 
@@ -346,7 +347,7 @@ internal_nis_getpwent_r (struct passwd *pwd, char *buffer, size_t buflen,
 	  free (oldkey);
 	  oldkey = outkey;
 	  oldkeylen = keylen;
-	  new_start = 0;
+	  new_start = false;
 	}
     }
   while (parse_res < 1);
@@ -399,16 +400,19 @@ _nss_nis_getpwnam_r (const char *name, struct passwd *pwd,
     }
 
   /* Check for adjunct style secret passwords.  They can be recognized
-     by a password starting with "##".  */
+     by a password starting with "##". We do not use it if the
+     passwd.adjunct.byname table is supposed to be used as a shadow.byname
+     replacement.  */
   char *result2;
   int len2;
   char *p = strchr (result, ':');
-  if (p != NULL	/* This better should be true in all cases.  */
+  if ((_nsl_default_nss () & NSS_FLAG_ADJUNCT_AS_SHADOW) == 0
+      && p != NULL	/* This better should be true in all cases.  */
       && p[1] == '#' && p[2] == '#'
       && yp_match (domain, "passwd.adjunct.byname", name, namelen,
 		   &result2, &len2) == YPERR_SUCCESS)
     {
-      /* We found a passwd.adjunct entry.  Merge encrypted password
+      /* We found a passwd.adjunct.byname entry.  Merge encrypted password
 	 therein into original result.  */
       char *encrypted = strchr (result2, ':');
       char *endp;
@@ -465,7 +469,7 @@ _nss_nis_getpwnam_r (const char *name, struct passwd *pwd,
   if (__builtin_expect (parse_res < 1, 0))
     {
       if (parse_res == -1)
-        return NSS_STATUS_TRYAGAIN;
+	return NSS_STATUS_TRYAGAIN;
       else
 	return NSS_STATUS_NOTFOUND;
     }
@@ -498,18 +502,21 @@ _nss_nis_getpwuid_r (uid_t uid, struct passwd *pwd,
     }
 
   /* Check for adjunct style secret passwords.  They can be recognized
-     by a password starting with "##".  */
+     by a password starting with "##".  We do not use it if the
+     passwd.adjunct.byname table is supposed to be used as a shadow.byname
+     replacement.  */
   char *result2;
   int len2;
   size_t namelen;
   char *p = strchr (result, ':');
-  if (p != NULL	/* This better should be true in all cases.  */
+  if ((_nsl_default_nss () & NSS_FLAG_ADJUNCT_AS_SHADOW) == 0
+      && p != NULL	/* This better should be true in all cases.  */
       && p[1] == '#' && p[2] == '#'
       && (namelen = p - result,
 	  yp_match (domain, "passwd.adjunct.byname", result, namelen,
 		    &result2, &len2)) == YPERR_SUCCESS)
     {
-      /* We found a passwd.adjunct entry.  Merge encrypted password
+      /* We found a passwd.adjunct.byname entry.  Merge encrypted password
 	 therein into original result.  */
       char *encrypted = strchr (result2, ':');
       char *endp;
@@ -567,7 +574,7 @@ _nss_nis_getpwuid_r (uid_t uid, struct passwd *pwd,
   if (__builtin_expect (parse_res < 1, 0))
     {
       if (parse_res == -1)
-        return NSS_STATUS_TRYAGAIN;
+	return NSS_STATUS_TRYAGAIN;
      else
        return NSS_STATUS_NOTFOUND;
     }
diff --git a/nis/nss_nis/nis-spwd.c b/nis/nss_nis/nis-spwd.c
index 0fc4e17..3cf913b 100644
--- a/nis/nss_nis/nis-spwd.c
+++ b/nis/nss_nis/nis-spwd.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1996-1998,2001,2002,2003,2006 Free Software Foundation, Inc.
+/* Copyright (C) 1996-1998,2001-2003,2006,2010 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.
 
@@ -31,6 +31,7 @@
 #include <rpcsvc/ypclnt.h>
 
 #include "nss-nis.h"
+#include <libnsl.h>
 
 /* Get the declaration of the parser function.  */
 #define ENTNAME spent
@@ -41,7 +42,8 @@
 /* Protect global state against multiple changers */
 __libc_lock_define_initialized (static, lock)
 
-static bool_t new_start = 1;
+static bool new_start = true;
+static bool ent_adjunct_used;
 static char *oldkey;
 static int oldkeylen;
 
@@ -50,7 +52,8 @@ _nss_nis_setspent (int stayopen)
 {
   __libc_lock_lock (lock);
 
-  new_start = 1;
+  new_start = true;
+  ent_adjunct_used = false;
   free (oldkey);
   oldkey = NULL;
   oldkeylen = 0;
@@ -83,32 +86,50 @@ internal_nis_getspent_r (struct spwd *sp, char *buffer, size_t buflen,
       int yperr;
 
       if (new_start)
-        yperr = yp_first (domain, "shadow.byname", &outkey, &keylen, &result,
-			  &len);
+	{
+	  yperr = yp_first (domain, "shadow.byname", &outkey, &keylen, &result,
+			    &len);
+	  if (__builtin_expect (yperr == YPERR_MAP, 0)
+	      && (_nsl_default_nss () & NSS_FLAG_ADJUNCT_AS_SHADOW))
+	    {
+	      free (result);
+	      yperr = yp_first (domain, "passwd.adjunct.byname", &outkey,
+				&keylen, &result, &len);
+	      ent_adjunct_used = true;
+	    }
+	}
       else
-        yperr = yp_next (domain, "shadow.byname", oldkey, oldkeylen, &outkey,
-			 &keylen, &result, &len);
+	yperr = yp_next (domain, (ent_adjunct_used
+				  ? "passwd.adjunct.byname" : "shadow.byname"),
+			 oldkey, oldkeylen, &outkey, &keylen, &result, &len);
 
       if (__builtin_expect (yperr != YPERR_SUCCESS, 0))
-        {
+	{
 	  enum nss_status retval = yperr2nss (yperr);
 
 	  if (retval == NSS_STATUS_TRYAGAIN)
 	    *errnop = errno;
-          return retval;
-        }
+	  return retval;
+	}
 
-      if (__builtin_expect ((size_t) (len + 1) > buflen, 0))
-        {
-          free (result);
+      if (__builtin_expect ((size_t) (len + (ent_adjunct_used ? 3 : 1))
+			    > buflen, 0))
+	{
+	  free (result);
 	  *errnop = ERANGE;
-          return NSS_STATUS_TRYAGAIN;
-        }
+	  return NSS_STATUS_TRYAGAIN;
+	}
 
       char *p = strncpy (buffer, result, len);
-      buffer[len] = '\0';
+      if (ent_adjunct_used)
+	/* This is an ugly trick.  The format of passwd.adjunct.byname almost
+	   matches the shadow.byname format except that the last two fields
+	   are missing.  Synthesize them by marking them empty.  */
+	strcpy (&buffer[len], "::");
+      else
+	buffer[len] = '\0';
       while (isspace (*p))
-        ++p;
+	++p;
       free (result);
 
       parse_res = _nss_files_parse_spent (p, sp, (void *) buffer, buflen,
@@ -123,7 +144,7 @@ internal_nis_getspent_r (struct spwd *sp, char *buffer, size_t buflen,
       free (oldkey);
       oldkey = outkey;
       oldkeylen = keylen;
-      new_start = 0;
+      new_start = false;
     }
   while (!parse_res);
 
@@ -154,15 +175,25 @@ _nss_nis_getspnam_r (const char *name, struct spwd *sp,
       *errnop = EINVAL;
       return NSS_STATUS_UNAVAIL;
     }
+  const size_t name_len = strlen (name);
 
   char *domain;
   if (__builtin_expect (yp_get_default_domain (&domain), 0))
     return NSS_STATUS_UNAVAIL;
 
+  bool adjunct_used = false;
   char *result;
   int len;
-  int yperr = yp_match (domain, "shadow.byname", name, strlen (name), &result,
+  int yperr = yp_match (domain, "shadow.byname", name, name_len, &result,
 			&len);
+  if (__builtin_expect (yperr == YPERR_MAP, 0)
+      && (_nsl_default_nss () & NSS_FLAG_ADJUNCT_AS_SHADOW))
+    {
+      free (result);
+      yperr = yp_match (domain, "passwd.adjunct.byname", name, name_len,
+			&result, &len);
+      adjunct_used = true;
+    }
 
   if (__builtin_expect (yperr != YPERR_SUCCESS, 0))
     {
@@ -173,7 +204,7 @@ _nss_nis_getspnam_r (const char *name, struct spwd *sp,
       return retval;
     }
 
-  if (__builtin_expect ((size_t) (len + 1) > buflen, 0))
+  if (__builtin_expect ((size_t) (len + (adjunct_used ? 3 : 1)) > buflen, 0))
     {
       free (result);
       *errnop = ERANGE;
@@ -181,7 +212,13 @@ _nss_nis_getspnam_r (const char *name, struct spwd *sp,
     }
 
   char *p = strncpy (buffer, result, len);
-  buffer[len] = '\0';
+  if (__builtin_expect (adjunct_used, false))
+    /* This is an ugly trick.  The format of passwd.adjunct.byname almost
+       matches the shadow.byname format except that the last two fields
+       are missing.  Synthesize them by marking them empty.  */
+    strcpy (&buffer[len], "::");
+  else
+    buffer[len] = '\0';
   while (isspace (*p))
     ++p;
   free (result);