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authorDavid Daney <ddaney@caviumnetworks.com>2010-07-19 20:14:56 (GMT)
committerRalf Baechle <ralf@linux-mips.org>2010-08-05 12:26:05 (GMT)
commit1091458d09e1a0788268578001f279250d2c0844 (patch)
tree9a02e6153d6658cab4b653ba845e68b161cac908 /arch/mips
parentb3b3c176d9150af542d9ba5e5b292d233883ff85 (diff)
downloadlinux-1091458d09e1a0788268578001f279250d2c0844.tar.xz
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')
-rw-r--r--arch/mips/include/asm/processor.h11
-rw-r--r--arch/mips/kernel/syscall.c21
2 files changed, 31 insertions, 1 deletions
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 5d33b72..24d91f8 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -34,6 +34,11 @@ extern void (*cpu_wait)(void);
extern unsigned int vced_count, vcei_count;
/*
+ * MIPS does have an arch_pick_mmap_layout()
+ */
+#define HAVE_ARCH_PICK_MMAP_LAYOUT 1
+
+/*
* A special page (the vdso) is mapped into all processes at the very
* top of the virtual memory space.
*/
@@ -52,6 +57,9 @@ extern unsigned int vced_count, vcei_count;
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE ((TASK_SIZE / 3) & ~(PAGE_SIZE))
+
+#define TASK_IS_32BIT_ADDR 1
+
#endif
#ifdef CONFIG_64BIT
@@ -77,6 +85,9 @@ extern unsigned int vced_count, vcei_count;
PAGE_ALIGN(TASK_SIZE32 / 3) : PAGE_ALIGN(TASK_SIZE / 3))
#define TASK_SIZE_OF(tsk) \
(test_tsk_thread_flag(tsk, TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE)
+
+#define TASK_IS_32BIT_ADDR test_thread_flag(TIF_32BIT_ADDR)
+
#endif
#ifdef __KERNEL__
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index dd81b0f..9824a82 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)