[perl #43105] [PATCH] function mmd.c::mmd_expand_y: newly allocated memory unitialized

[Mehmet Yavuz Selim Soyturk]

# New Ticket Created by  "Mehmet Yavuz Selim Soyturk" 
# Please include the string:  [perl #43105]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=43105 >


Function mmd_expand_y in src/mmd.c allocates new memory for the mmd
table, but does not initialize the newy allocated memory to NULL,
which causes segfaults for some cases. The attached patch solves that
problem.


-- 
Mehmet

Index: src/mmd.c
===================================================================
--- src/mmd.c	(revision 18722)
+++ src/mmd.c	(working copy)
@@ -624,18 +624,30 @@
 mmd_expand_y(Interp *interp, INTVAL func_nr, INTVAL new_y)
 {
     funcptr_t *new_table;
-    UINTVAL    new_size;
+    UINTVAL x;
+    UINTVAL y;
+    UINTVAL i;
+    UINTVAL new_size;
     MMD_table * const table = interp->binop_mmd_funcs + func_nr;
 
     assert(table->x);
+    
+    x = table->x;
+    y = table->y;
 
-    new_size = sizeof (funcptr_t) * table->x * new_y;
+    new_size = sizeof (funcptr_t) * x * new_y;
 
     if (table->mmd_funcs)
-        table->mmd_funcs = mem_sys_realloc(table->mmd_funcs, new_size);
+        new_table = mem_sys_realloc(table->mmd_funcs, new_size);
     else
-        table->mmd_funcs = (funcptr_t *)mem_sys_allocate(new_size);
-
+        new_table = (funcptr_t *)mem_sys_allocate(new_size);
+    
+    /* Initialize the newly allocated space with NULLs */
+    for (i = x * y; i < x * new_y; i++) {
+        new_table[i] = NULL;
+    }
+    
+    table->mmd_funcs = new_table;
     table->y = new_y;
 }