Commit 4699c8e4 authored by Cui GaoSheng's avatar Cui GaoSheng Committed by Zheng Zengkai
Browse files

arm32: kaslr: Fix the bitmap error 

Offering: HULK
hulk inclusion
category: bugfix
bugzilla: 172972 https://gitee.com/openeuler/kernel/issues/I4DDEL



-----------------------------------------------------------------

The value returned by get_region_number may exceed the
usable memory positions indexed by bitmap, it will cause
probabilistic boot failure in images which enabled kaslr.

Fixes: 156b9ca54d0d ("[Backport] ARM: decompressor: add KASLR support")
Signed-off-by: default avatarCui GaoSheng <cuigaosheng1@huawei.com>
Reviewed-by: default avatarXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: default avatarChen Jun <chenjun102@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 2bab5c83

arch/arm/boot/compressed/kaslr.c

+11 −6
Original line number Diff line number Diff line
@@ -178,13 +178,18 @@ static u32 count_suitable_regions(const void *fdt, struct regions *regions, 
	return ret;

}



static u32 get_region_number(u32 num, u32 *bitmap)

/* The caller ensures that num is within the range of regions.*/

static u32 get_region_number(u32 num, u32 *bitmap, u32 size)

{

	u32 i;

	u32 i, cnt = size * BITS_PER_BYTE * sizeof(u32);



	for (i = 0; i < cnt; i++) {

		if (bitmap[i >> 5] & BIT(i & 0x1f))

			continue;

		if (num-- == 0)

			break;

	}



	for (i = 0; num > 0; i++)

		if (!(bitmap[i >> 5] & BIT(i & 0x1f)))

			num--;

	return i;

}
@@ -453,7 +458,7 @@ u32 kaslr_early_init(u32 *kaslr_offset, u32 image_base, u32 image_size, 
	num = ((u16)seed * count) >> 16;

	puthex32(num);



	*kaslr_offset = get_region_number(num, bitmap) * SZ_2M;

	*kaslr_offset = get_region_number(num, bitmap, sizeof(bitmap) / sizeof(u32)) * SZ_2M;

	puthex32(*kaslr_offset);



	return *kaslr_offset;