diff -pruN glibc-2.12-2-gc4ccff1/nis/nss_compat/compat-initgroups.c glibc-2.12-2-gc4ccff1.patched/nis/nss_compat/compat-initgroups.c

--- glibc-2.12-2-gc4ccff1/nis/nss_compat/compat-initgroups.c	2010-05-04 16:57:23.000000000 +0530

+++ glibc-2.12-2-gc4ccff1.patched/nis/nss_compat/compat-initgroups.c	2012-02-21 11:11:19.877008465 +0530

@@ -297,6 +297,8 @@ getgrent_next_nss (ent_t *ent, char *buf

       if (nss_initgroups_dyn (user, group, &mystart, &mysize, &mygroups,

 			      limit, errnop) == NSS_STATUS_SUCCESS)

 	{

+	  status = NSS_STATUS_NOTFOUND;

+

 	  /* If there is no blacklist we can trust the underlying

 	     initgroups implementation.  */

 	  if (ent->blacklist.current <= 1)

@@ -309,6 +311,7 @@ getgrent_next_nss (ent_t *ent, char *buf

 		 overwrite the pointer with one to a bigger buffer.  */

 	      char *tmpbuf = buffer;

 	      size_t tmplen = buflen;

+	      bool use_malloc = false;

 	      for (int i = 0; i < mystart; i++)

 		{

@@ -316,21 +319,36 @@ getgrent_next_nss (ent_t *ent, char *buf

 						   tmpbuf, tmplen, errnop))

 			 == NSS_STATUS_TRYAGAIN

 			 && *errnop == ERANGE)

-		    if (tmpbuf == buffer)

-		      {

-			tmplen *= 2;

-			tmpbuf = __alloca (tmplen);

-		      }

-		    else

-		      tmpbuf = extend_alloca (tmpbuf, tmplen, 2 * tmplen);

+                    {

+                      if (__libc_use_alloca (tmplen * 2))

+                        {

+                          if (tmpbuf == buffer)

+                            {

+                              tmplen *= 2;

+                              tmpbuf = __alloca (tmplen);

+                            }

+                          else

+                            tmpbuf = extend_alloca (tmpbuf, tmplen, tmplen * 2);

+                        }

+                      else

+                        {

+                          tmplen *= 2;

+                          char *newbuf = realloc (use_malloc ? tmpbuf : NULL, tmplen);

+                    

+                          if (newbuf == NULL)

+                            {

+                              status = NSS_STATUS_TRYAGAIN;

+			      goto done;

+                            }

+                          use_malloc = true;

+                          tmpbuf = newbuf;

+                        }

+                    }

 		  if (__builtin_expect  (status != NSS_STATUS_NOTFOUND, 1))

 		    {

 		      if (__builtin_expect  (status != NSS_STATUS_SUCCESS, 0))

-			{

-			  free (mygroups);

-			  return status;

-			}

+		        goto done;

 		      if (!in_blacklist (grpbuf.gr_name,

 					 strlen (grpbuf.gr_name), ent)

@@ -348,11 +366,17 @@ getgrent_next_nss (ent_t *ent, char *buf

 			}

 		    }

 		}

+

+		status = NSS_STATUS_NOTFOUND;

+

+ done:

+		if (use_malloc)

+		  free (tmpbuf);

 	    }

 	  free (mygroups);

-	  return NSS_STATUS_NOTFOUND;

+	  return status;

 	}

       free (mygroups);

@@ -506,6 +530,7 @@ _nss_compat_initgroups_dyn (const char *

   char *tmpbuf;

   enum nss_status status;

   ent_t intern = { true, false, false, NULL, {NULL, 0, 0} };

+  bool use_malloc = false;

   status = internal_setgrent (&intern;;

   if (status != NSS_STATUS_SUCCESS)

@@ -519,13 +544,32 @@ _nss_compat_initgroups_dyn (const char *

 					    user, group, start, size,

 					    groupsp, limit, errnop))

 	     == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)

-	tmpbuf = extend_alloca (tmpbuf, buflen, 2 * buflen);

+        if (__libc_use_alloca (buflen * 2))

+          tmpbuf = extend_alloca (tmpbuf, buflen, 2 * buflen);

+        else

+          {

+            buflen *= 2;

+            char *newbuf = realloc (use_malloc ? tmpbuf : NULL, buflen);

+            if (newbuf == NULL)

+              {

+                status = NSS_STATUS_TRYAGAIN;

+                goto done;

+              }

+            use_malloc = true;

+            tmpbuf = newbuf;

+          }

     }

   while (status == NSS_STATUS_SUCCESS);

+  status = NSS_STATUS_SUCCESS;

+

+ done:

+  if (use_malloc)

+    free (tmpbuf);

+

   internal_endgrent (&intern;;

-  return NSS_STATUS_SUCCESS;

+  return status;

 }