Uprev NSS to 3.18 RTM

nss/lib/ckfw/builtins/bfind.c

Index: nss/lib/ckfw/builtins/bfind.c
diff --git a/nss/lib/ckfw/builtins/bfind.c b/nss/lib/ckfw/builtins/bfind.c
index e31c4ef099875e88d7614675bb56c21409c55089..df35ed8b689ff7e15dbab424391d8d86ade2d39f 100644
--- a/nss/lib/ckfw/builtins/bfind.c
+++ b/nss/lib/ckfw/builtins/bfind.c
@@ -183,7 +183,16 @@ nss_builtins_FindObjectsInit
   NSSArena *arena;
   NSSCKMDFindObjects *rv = (NSSCKMDFindObjects *)NULL;
   struct builtinsFOStr *fo = (struct builtinsFOStr *)NULL;
-  builtinsInternalObject **temp = (builtinsInternalObject **)NULL;
+
+  /*
+   * 99% of the time we get 0 or 1 matches. So we start with a small
+   * stack-allocated array to hold the matches and switch to a heap-allocated
+   * array later if the number of matches exceeds STACK_BUF_LENGTH.
+   */
+  #define STACK_BUF_LENGTH 1
+  builtinsInternalObject *stackTemp[STACK_BUF_LENGTH];
+  builtinsInternalObject **temp = stackTemp;
+  PRBool tempIsHeapAllocated = PR_FALSE;
   PRUint32 i;
 
   arena = NSSArena_Create();
@@ -211,17 +220,24 @@ nss_builtins_FindObjectsInit
   rv->Next = builtins_mdFindObjects_Next;
   rv->null = (void *)NULL;
 
-  temp = nss_ZNEWARRAY((NSSArena *)NULL, builtinsInternalObject *, 
-                       nss_builtins_nObjects);
-  if( (builtinsInternalObject **)NULL == temp ) {
-    *pError = CKR_HOST_MEMORY;
-    goto loser;
-  }
-
   for( i = 0; i < nss_builtins_nObjects; i++ ) {
     builtinsInternalObject *o = (builtinsInternalObject *)&nss_builtins_data[i];
 
     if( CK_TRUE == builtins_match(pTemplate, ulAttributeCount, o) ) {
+      if( fo->n == STACK_BUF_LENGTH ) {
+        /* Switch from the small stack array to a heap-allocated array large
+         * enough to handle matches in all remaining cases. */
+        temp = nss_ZNEWARRAY((NSSArena *)NULL, builtinsInternalObject *,
+                             fo->n + nss_builtins_nObjects - i);
+        if( (builtinsInternalObject **)NULL == temp ) {
+          *pError = CKR_HOST_MEMORY;
+          goto loser;
+        }
+        tempIsHeapAllocated = PR_TRUE;
+        (void)nsslibc_memcpy(temp, stackTemp,
+                             sizeof(builtinsInternalObject *) * fo->n);
+      }
+
       temp[ fo->n ] = o;
       fo->n++;
     }
@@ -234,13 +250,17 @@ nss_builtins_FindObjectsInit
   }
 
   (void)nsslibc_memcpy(fo->objs, temp, sizeof(builtinsInternalObject *) * fo->n);
-  nss_ZFreeIf(temp);
-  temp = (builtinsInternalObject **)NULL;
+  if (tempIsHeapAllocated) {
+    nss_ZFreeIf(temp);
+    temp = (builtinsInternalObject **)NULL;
+  }
 
   return rv;
 
  loser:
-  nss_ZFreeIf(temp);
+  if (tempIsHeapAllocated) {
+    nss_ZFreeIf(temp);
+  }
   nss_ZFreeIf(fo);
   nss_ZFreeIf(rv);
   if ((NSSArena *)NULL != arena) {