---

yaml --- r: 204546 b: refs/heads/master c: 652b14a h: refs/heads/master v: v3
git-mirror · Aug 5, 2010 · e630ddd · e630ddd
1 parent 7b7cff1
commit e630ddd
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Showing 3 changed files with 34 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1091458d09e1a0788268578001f279250d2c0844
+refs/heads/master: 652b14aa84961fa391184ccbaf559a537d33b28c
diff --git a/trunk/arch/mips/include/asm/elf.h b/trunk/arch/mips/include/asm/elf.h
@@ -372,4 +372,9 @@ extern const char *__elf_platform;
 struct linux_binprm;
 extern int arch_setup_additional_pages(struct linux_binprm *bprm,
 				       int uses_interp);
+
+struct mm_struct;
+extern unsigned long arch_randomize_brk(struct mm_struct *mm);
+#define arch_randomize_brk arch_randomize_brk
+
 #endif /* _ASM_ELF_H */
diff --git a/trunk/arch/mips/kernel/syscall.c b/trunk/arch/mips/kernel/syscall.c
@@ -30,6 +30,7 @@
 #include <linux/uaccess.h>
 #include <linux/slab.h>
 #include <linux/random.h>
+#include <linux/elf.h>
 
 #include <asm/asm.h>
 #include <asm/branch.h>
@@ -153,6 +154,33 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 	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)