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authorDavid Daney <ddaney@caviumnetworks.com>2010-07-19 13:14:56 -0700
committerRalf Baechle <ralf@linux-mips.org>2010-08-05 13:26:05 +0100
commit1091458d09e1a0788268578001f279250d2c0844 (patch)
tree9a02e6153d6658cab4b653ba845e68b161cac908 /arch/mips/kernel/syscall.c
parentb3b3c176d9150af542d9ba5e5b292d233883ff85 (diff)
MIPS: Randomize mmap if randomize_va_space is set
Fairly straight forward: For 32-bit address spaces randomize within a 16MB space, for 64-bit within a 256MB space. Signed-off-by: David Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1480/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/syscall.c')
-rw-r--r--arch/mips/kernel/syscall.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index dd81b0f87518..9824a829f61d 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -29,6 +29,7 @@
#include <linux/ipc.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
+#include <linux/random.h>
#include <asm/asm.h>
#include <asm/branch.h>
@@ -116,7 +117,7 @@ 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 +135,24 @@ 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;
+}
+
SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags, unsigned long,
fd, off_t, offset)