Code:  void * calloc(size_t n, size_t lb)
 {
 #   if defined(GC_LINUX_THREADS) /* && !defined(USE_PROC_FOR_LIBRARIES) */
         /* libpthread allocated some memory that is only pointed to by  */
         /* mmapped thread stacks.  Make sure it's not collectable.      */
        {
          static GC_bool lib_bounds_set = FALSE;
          ptr_t caller = (ptr_t)__builtin_return_address(0);
          /* This test does not need to ensure memory visibility, since */
          /* the bounds will be set when/if we create another thread.   */
          if (!EXPECT(lib_bounds_set, TRUE)) {
            GC_init_lib_bounds();
            lib_bounds_set = TRUE;
          }
          if (((word)caller >= (word)GC_libpthread_start
               && (word)caller < (word)GC_libpthread_end)
              || ((word)caller >= (word)GC_libld_start
                  && (word)caller < (word)GC_libld_end))
            return GC_malloc_uncollectable(n*lb);
          /* The two ranges are actually usually adjacent, so there may */
          /* be a way to speed this up.                                 */
        }
#   endif
    return((void *)REDIRECT_MALLOC(n*lb));
}

Vulnerability Type: Overflow 
CWE ID: CWE-189
Summary: Multiple integer overflows in the (1) GC_generic_malloc and (2) calloc functions in malloc.c, and the (3) GC_generic_malloc_ignore_off_page function in mallocx.c in Boehm-Demers-Weiser GC (libgc) before 7.2 make it easier for context-dependent attackers to perform memory-related attacks such as buffer overflows via a large size value, which causes less memory to be allocated than expected.
Commit Message: Fix calloc() overflow

* malloc.c (calloc): Check multiplication overflow in calloc(),
assuming REDIRECT_MALLOC.