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Commit b2eca427 authored by Tony Lu's avatar Tony Lu Committed by Chris Metcalf
Browse files

tile: support ASLR fully 



With this change, tile Linux now supports address-space layout
randomization for shared objects, stack, heap and vdso.

Acked-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarTony Lu <zlu@tilera.com>
Signed-off-by: default avatarChris Metcalf <cmetcalf@tilera.com>
parent 9b5bbf72

arch/tile/include/asm/elf.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -137,6 +137,10 @@ do { \ 
	NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_BASE); \

	NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_BASE); \

} while (0)

} while (0)





struct mm_struct;

extern unsigned long arch_randomize_brk(struct mm_struct *mm);

#define arch_randomize_brk arch_randomize_brk



#ifdef CONFIG_COMPAT

#ifdef CONFIG_COMPAT





#define COMPAT_ELF_PLATFORM "tilegx-m32"

#define COMPAT_ELF_PLATFORM "tilegx-m32"

arch/tile/mm/mmap.c

+22 −2
Original line number Original line Diff line number Diff line
@@ -58,16 +58,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm) 
#else

#else

	int is_32bit = 0;

	int is_32bit = 0;

#endif

#endif

	unsigned long random_factor = 0UL;



	/*

	 *  8 bits of randomness in 32bit mmaps, 24 address space bits

	 * 12 bits of randomness in 64bit mmaps, 28 address space bits

	 */

	if (current->flags & PF_RANDOMIZE) {

		if (is_32bit)

			random_factor = get_random_int() % (1<<8);

		else

			random_factor = get_random_int() % (1<<12);



		random_factor <<= PAGE_SHIFT;

	}





	/*

	/*

	 * Use standard layout if the expected stack growth is unlimited

	 * Use standard layout if the expected stack growth is unlimited

	 * or we are running native 64 bits.

	 * or we are running native 64 bits.

	 */

	 */

	if (!is_32bit || rlimit(RLIMIT_STACK) == RLIM_INFINITY) {

	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) {

		mm->mmap_base = TASK_UNMAPPED_BASE;

		mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;

		mm->get_unmapped_area = arch_get_unmapped_area;

		mm->get_unmapped_area = arch_get_unmapped_area;

	} else {

	} else {

		mm->mmap_base = mmap_base(mm);

		mm->mmap_base = mmap_base(mm);

		mm->get_unmapped_area = arch_get_unmapped_area_topdown;

		mm->get_unmapped_area = arch_get_unmapped_area_topdown;

	}

	}

}

}



unsigned long arch_randomize_brk(struct mm_struct *mm)

{

	unsigned long range_end = mm->brk + 0x02000000;

	return randomize_range(mm->brk, range_end, 0) ? : mm->brk;

}