MIPS: Enable heap randomization.

[sfrench/cifs-2.6.git] / arch / mips / kernel / syscall.c

diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index dd81b0f875183d887e97996ee14f961f79055118..58bab2ef257fae911623b6296879db2d9d427578 100644 (file)
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -29,6 +29,8 @@
 #include <linux/ipc.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/elf.h>
 
 #include <asm/asm.h>
 #include <asm/branch.h>
@@ -116,7 +118,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
                    (!vmm || addr + len <= vmm->vm_start))
                        return addr;
        }
-       addr = TASK_UNMAPPED_BASE;
+       addr = current->mm->mmap_base;
        if (do_color_align)
                addr = COLOUR_ALIGN(addr, pgoff);
        else
@@ -134,6 +136,51 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
        }
 }
 
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+       unsigned long random_factor = 0UL;
+
+       if (current->flags & PF_RANDOMIZE) {
+               random_factor = get_random_int();
+               random_factor = random_factor << PAGE_SHIFT;
+               if (TASK_IS_32BIT_ADDR)
+                       random_factor &= 0xfffffful;
+               else
+                       random_factor &= 0xffffffful;
+       }
+
+       mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
+       mm->get_unmapped_area = arch_get_unmapped_area;
+       mm->unmap_area = arch_unmap_area;
+}
+
+static inline unsigned long brk_rnd(void)
+{
+       unsigned long rnd = get_random_int();
+
+       rnd = rnd << PAGE_SHIFT;
+       /* 8MB for 32bit, 256MB for 64bit */
+       if (TASK_IS_32BIT_ADDR)
+               rnd = rnd & 0x7ffffful;
+       else
+               rnd = rnd & 0xffffffful;
+
+       return rnd;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+       unsigned long base = mm->brk;
+       unsigned long ret;
+
+       ret = PAGE_ALIGN(base + brk_rnd());
+
+       if (ret < mm->brk)
+               return mm->brk;
+
+       return ret;
+}
+
 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
        unsigned long, prot, unsigned long, flags, unsigned long,
        fd, off_t, offset)