#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/time_namespace.h>
+#include <linux/random.h>
#include <vdso/datapage.h>
#include <asm/vdso.h>
}
early_initcall(vdso_getcpu_init); /* Must be called before SMP init */
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+static int map_vdso(unsigned long addr, unsigned long vdso_mapping_len)
{
- unsigned long vdso_text_len, vdso_mapping_len;
- unsigned long vvar_start, vdso_text_start;
+ unsigned long vvar_start, vdso_text_start, vdso_text_len;
struct vm_special_mapping *vdso_mapping;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
vdso_text_len = vdso64_end - vdso64_start;
vdso_mapping = &vdso64_mapping;
}
- vdso_mapping_len = vdso_text_len + VVAR_NR_PAGES * PAGE_SIZE;
- vvar_start = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
+ vvar_start = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0);
rc = vvar_start;
if (IS_ERR_VALUE(vvar_start))
goto out;
return rc;
}
+static unsigned long vdso_addr(unsigned long start, unsigned long len)
+{
+ unsigned long addr, end, offset;
+
+ /*
+ * Round up the start address. It can start out unaligned as a result
+ * of stack start randomization.
+ */
+ start = PAGE_ALIGN(start);
+
+ /* Round the lowest possible end address up to a PMD boundary. */
+ end = (start + len + PMD_SIZE - 1) & PMD_MASK;
+ if (end >= VDSO_BASE)
+ end = VDSO_BASE;
+ end -= len;
+
+ if (end > start) {
+ offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
+ addr = start + (offset << PAGE_SHIFT);
+ } else {
+ addr = start;
+ }
+ return addr;
+}
+
+unsigned long vdso_size(void)
+{
+ unsigned long size = VVAR_NR_PAGES * PAGE_SIZE;
+
+ if (is_compat_task())
+ size += vdso32_end - vdso32_start;
+ else
+ size += vdso64_end - vdso64_start;
+ return PAGE_ALIGN(size);
+}
+
+int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+ unsigned long addr = VDSO_BASE;
+ unsigned long size = vdso_size();
+
+ if (current->flags & PF_RANDOMIZE)
+ addr = vdso_addr(current->mm->start_stack + PAGE_SIZE, size);
+ return map_vdso(addr, size);
+}
+
static struct page ** __init vdso_setup_pages(void *start, void *end)
{
int pages = (end - start) >> PAGE_SHIFT;