2009-05-18  Jakub Jelinek  <jakub@redhat.com>
	    Ulrich Drepper  <drepper@redhat.com>

	* nscd/nscd_helper.c (MINIMUM_HASHENTRY_SIZE): Define.
	(__nscd_cache_search): Assume each entry in the
	hash chain needs one hashentry and half of datahead.  Use
	MINIMUM_HASHENTRY_SIZE instead of sizeof(hashentry).

2009-05-16  Ulrich Drepper  <drepper@redhat.com>

	* nscd/nscd_helper.c (__nscd_cache_search): Fix exit condition in last
	patch.

2009-05-15  Ulrich Drepper  <drepper@redhat.com>

	* nscd/nscd_helper.c (__nscd_cache_search): Introduce loop counter.
	Use it if we absolutely cannot reach any more correct list elements
	because that many do not fit into the currently mapped database.

2009-05-14  Jakub Jelinek  <jakub@redhat.com>
 
	* nscd/nscd_helper.c: Include stddef.h.
	(__nscd_cache_search): Add datalen argument.  Use atomic_forced_read
	in a couple of places.  Return NULL if trail is not less than
	datasize, don't consider dataheads with length smaller than
	offsetof (struct datahead, data) + datalen.
	* nscd/nscd_client.h (__nscd_cache_search): Adjust prototype.
	* nscd/nscd_gethst_r.c (nscd_gethst_r): Adjust callers.
	* nscd/nscd_getpw_r.c (nscd_getpw_r): Likewise.
	* nscd/nscd_getgr_r.c (nscd_getgr_r): Likewise.
	* nscd/nscd_getai.c (__nscd_getai): Likewise.
	* nscd/nscd_initgroups.c (__nscd_getgrouplist): Likewise.

--- libc/nscd/nscd_helper.c
+++ libc/nscd/nscd_helper.c
@@ -21,6 +21,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
@@ -467,23 +468,36 @@ __nscd_get_map_ref (request_type type, const char *name,
 }
 
 
+/* Using sizeof (hashentry) is not always correct to determine the size of
+   the data structure as found in the nscd cache.  The program could be
+   a 64-bit process and nscd could be a 32-bit process.  In this case
+   sizeof (hashentry) would overestimate the size.  The following is
+   the minimum size of such an entry, good enough for our tests here.  */
+#define MINIMUM_HASHENTRY_SIZE \
+  (offsetof (struct hashentry, dellist) + sizeof (int32_t))
+
+
 /* Don't return const struct datahead *, as eventhough the record
    is normally constant, it can change arbitrarily during nscd
    garbage collection.  */
 struct datahead *
 __nscd_cache_search (request_type type, const char *key, size_t keylen,
-		     const struct mapped_database *mapped)
+		     const struct mapped_database *mapped, size_t datalen)
 {
   unsigned long int hash = __nis_hash (key, keylen) % mapped->head->module;
   size_t datasize = mapped->datasize;
 
   ref_t trail = mapped->head->array[hash];
+  trail = atomic_forced_read (trail);
   ref_t work = trail;
+  size_t loop_cnt = datasize / (MINIMUM_HASHENTRY_SIZE
+				+ offsetof (struct datahead, data) / 2);
   int tick = 0;
 
-  while (work != ENDREF && work + sizeof (struct hashentry) <= datasize)
+  while (work != ENDREF && work + MINIMUM_HASHENTRY_SIZE <= datasize)
     {
       struct hashentry *here = (struct hashentry *) (mapped->data + work);
+      ref_t here_key, here_packet;
 
 #ifndef _STRING_ARCH_unaligned
       /* Although during garbage collection when moving struct hashentry
@@ -498,13 +512,14 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
 
       if (type == here->type
 	  && keylen == here->len
-	  && here->key + keylen <= datasize
-	  && memcmp (key, mapped->data + here->key, keylen) == 0
-	  && here->packet + sizeof (struct datahead) <= datasize)
+	  && (here_key = atomic_forced_read (here->key)) + keylen <= datasize
+	  && memcmp (key, mapped->data + here_key, keylen) == 0
+	  && ((here_packet = atomic_forced_read (here->packet))
+	      + sizeof (struct datahead) <= datasize))
 	{
 	  /* We found the entry.  Increment the appropriate counter.  */
 	  struct datahead *dh
-	    = (struct datahead *) (mapped->data + here->packet);
+	    = (struct datahead *) (mapped->data + here_packet);
 
 #ifndef _STRING_ARCH_unaligned
 	  if ((uintptr_t) dh & (__alignof__ (*dh) - 1))
@@ -513,14 +528,17 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
 
 	  /* See whether we must ignore the entry or whether something
 	     is wrong because garbage collection is in progress.  */
-	  if (dh->usable && here->packet + dh->allocsize <= datasize)
+	  if (dh->usable
+	      && here_packet + dh->allocsize <= datasize
+	      && (here_packet + offsetof (struct datahead, data) + datalen
+		  <= datasize))
 	    return dh;
 	}
 
-      work = here->next;
+      work = atomic_forced_read (here->next);
       /* Prevent endless loops.  This should never happen but perhaps
 	 the database got corrupted, accidentally or deliberately.  */
-      if (work == trail)
+      if (work == trail || loop_cnt-- == 0)
 	break;
       if (tick)
 	{
@@ -532,7 +550,11 @@ __nscd_cache_search (request_type type, const char *key, size_t keylen,
 	  if ((uintptr_t) trailelem & (__alignof__ (*trailelem) - 1))
 	    return NULL;
 #endif
-	  trail = trailelem->next;
+
+	  if (trail + MINIMUM_HASHENTRY_SIZE > datasize)
+	    return NULL;
+
+	  trail = atomic_forced_read (trailelem->next);
 	}
       tick = 1 - tick;
     }
--- libc/nscd/nscd-client.h
+++ libc/nscd/nscd-client.h
@@ -44,7 +44,7 @@
 /* Path for the configuration file.  */
 #define _PATH_NSCDCONF	 "/etc/nscd.conf"
 
-/* Maximu allowed length for the key.  */
+/* Maximum allowed length for the key.  */
 #define MAXKEYLEN 1024
 
 
@@ -329,7 +329,8 @@ static inline int __nscd_drop_map_ref (struct mapped_database *map,
 extern struct datahead *__nscd_cache_search (request_type type,
 					     const char *key,
 					     size_t keylen,
-					     const struct mapped_database *mapped);
+					     const struct mapped_database *mapped,
+					     size_t datalen);
 
 /* Wrappers around read, readv and write that only read/write less than LEN
    bytes on error or EOF.  */
--- libc/nscd/nscd_gethst_r.c
+++ libc/nscd/nscd_gethst_r.c
@@ -137,7 +138,8 @@ nscd_gethst_r (const char *key, size_t keylen, request_type type,
   if (mapped != NO_MAPPING)
     {
       /* No const qualifier, as it can change during garbage collection.  */
-      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped);
+      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
+						    sizeof hst_resp);
       if (found != NULL)
 	{
 	  h_name = (char *) (&found->data[0].hstdata + 1);
--- libc/nscd/nscd_getpw_r.c
+++ libc/nscd/nscd_getpw_r.c
@@ -104,7 +104,8 @@ nscd_getpw_r (const char *key, size_t keylen, request_type type,
 
   if (mapped != NO_MAPPING)
     {
-      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped);
+      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
+						    sizeof pw_resp);
       if (found != NULL)
 	{
 	  pw_name = (const char *) (&found->data[0].pwdata + 1);
--- libc/nscd/nscd_getgr_r.c
+++ libc/nscd/nscd_getgr_r.c
@@ -107,7 +107,8 @@ nscd_getgr_r (const char *key, size_t keylen, request_type type,
 
   if (mapped != NO_MAPPING)
     {
-      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped);
+      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
+						    sizeof gr_resp);
       if (found != NULL)
 	{
 	  len = (const uint32_t *) (&found->data[0].grdata + 1);
--- libc/nscd/nscd_getai.c
+++ libc/nscd/nscd_getai.c
@@ -75,7 +76,7 @@ __nscd_getai (const char *key, struct nscd_ai_result **result, int *h_errnop)
   if (mapped != NO_MAPPING)
     {
       struct datahead *found = __nscd_cache_search (GETAI, key, keylen,
-						    mapped);
+						    mapped, sizeof ai_resp);
       if (found != NULL)
 	{
 	  respdata = (char *) (&found->data[0].aidata + 1);
--- libc/nscd/nscd_initgroups.c
+++ libc/nscd/nscd_initgroups.c
@@ -55,7 +55,8 @@ __nscd_getgrouplist (const char *user, gid_t group, long int *size,
   if (mapped != NO_MAPPING)
     {
       struct datahead *found = __nscd_cache_search (INITGROUPS, user,
-						    userlen, mapped);
+						    userlen, mapped,
+						    sizeof initgr_resp);
       if (found != NULL)
 	{
 	  respdata = (char *) (&found->data[0].initgrdata + 1);