Commit 33519182 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

[S390] Randomise the brk region 



Randomize heap address like other architectures do already.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a05c90f1

arch/s390/include/asm/elf.h

+3 −0
Original line number Diff line number Diff line
@@ -220,4 +220,7 @@ struct linux_binprm; 
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1

int arch_setup_additional_pages(struct linux_binprm *, int);



extern unsigned long arch_randomize_brk(struct mm_struct *mm);

#define arch_randomize_brk arch_randomize_brk



#endif

arch/s390/kernel/process.c

+18 −0
Original line number Diff line number Diff line
@@ -341,3 +341,21 @@ unsigned long arch_align_stack(unsigned long sp) 
		sp -= get_random_int() & ~PAGE_MASK;

	return sp & ~0xf;

}



static inline unsigned long brk_rnd(void)

{

	/* 8MB for 32bit, 1GB for 64bit */

	if (is_32bit_task())

		return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;

	else

		return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;

}



unsigned long arch_randomize_brk(struct mm_struct *mm)

{

	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());



	if (ret < mm->brk)

		return mm->brk;

	return ret;

}