[SPARC64]: Randomize mm->mmap_base when PF_RANDOMIZE is set.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 2 deletions

diff --git a/arch/sparc64/kernel/sys_sparc.c b/arch/sparc64/kernel/sys_sparc.c
index 9019b41fc02a..7a869138c37f 100644
--- a/arch/sparc64/kernel/sys_sparc.c
+++ b/arch/sparc64/kernel/sys_sparc.c
@@ -25,6 +25,7 @@
 #include <linux/syscalls.h>
 #include <linux/ipc.h>
 #include <linux/personality.h>
+#include <linux/random.h>
 
 #include <asm/uaccess.h>
 #include <asm/ipc.h>
@@ -358,6 +359,17 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, u
 /* Essentially the same as PowerPC... */
 void arch_pick_mmap_layout(struct mm_struct *mm)
 {
+        unsigned long random_factor = 0UL;
+
+        if (current->flags & PF_RANDOMIZE) {
+                random_factor = get_random_int();
+                if (test_thread_flag(TIF_32BIT))
+                        random_factor &= ((1 * 1024 * 1024) - 1);
+                else
+                        random_factor = ((random_factor << PAGE_SHIFT) &
+                                         0xffffffffUL);
+        }
+
         /*
          * Fall back to the standard layout if the personality
          * bit is set, or if the expected stack growth is unlimited:
@@ -366,7 +378,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
             (current->personality & ADDR_COMPAT_LAYOUT) ||
             current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY ||
             sysctl_legacy_va_layout) {
-                mm->mmap_base = TASK_UNMAPPED_BASE;
+                mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
                 mm->get_unmapped_area = arch_get_unmapped_area;
                 mm->unmap_area = arch_unmap_area;
         } else {
@@ -380,7 +392,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
                 if (gap > (task_size / 6 * 5))
                         gap = (task_size / 6 * 5);
 
-                mm->mmap_base = task_size - (gap & PAGE_MASK);
+                mm->mmap_base = PAGE_ALIGN(task_size - gap - random_factor);
                 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
                 mm->unmap_area = arch_unmap_area_topdown;
         }