Commit 8cccffc5 authored Oct 29, 2014 by Ard Biesheuvel Committed by Grant Likely Nov 04, 2014

of: check for size < 0 after rounding in early_init_dt_add_memory_arch



Memory regions passed to early_init_dt_add_memory_arch() are rounded to
PAGE_SIZE by subtracting the size of the leading fractional page from
the 'size' argument. However, size being a u64 type, if its value is
sufficiently small, the subtraction wraps around and produces a bogus
value, potentially leading to crashes.

Fix this by ignoring the memory range in such cases.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

parent 50ba08f3

drivers/of/fdt.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -928,6 +928,11 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
		const u64 phys_offset = __pa(PAGE_OFFSET);

		if (!PAGE_ALIGNED(base)) {
		if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
		base, base + size);
		return;
		}
		size -= PAGE_SIZE - (base & ~PAGE_MASK);
		base = PAGE_ALIGN(base);
		}