[PATCH] of: Check for phys_addr_t overflows in early_init_dt_add_memory_arch

[Laura Abbott]

The common early_init_dt_add_memory_arch takes the base and size
of a memory region as u64 types. The function never checks if
the base and size can actually fit in a phys_addr_t which may
be smaller than 64-bits. This may result in incorrect memory
being passed to memblock_add if the memory falls outside the
range of phys_addr_t. Add range checks for the base and size if
phys_addr_t is smaller than u64.

Reported-by: Geert Uytterhoeven <geert at linux-m68k.org>
Signed-off-by: Laura Abbott <lauraa at codeaurora.org>
---
Geert, can you drop my other patch and give this a test to see if it fixes
your bootup problem?

---
 drivers/of/fdt.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index c4cddf0..f72132c 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -880,6 +880,21 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 	const u64 phys_offset = __pa(PAGE_OFFSET);
 	base &= PAGE_MASK;
 	size &= PAGE_MASK;
+
+#ifndef CONFIG_ARCH_PHYS_ADDR_T_64BIT
+	if (base > ULONG_MAX) {
+		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
+				base, base + size);
+		return;
+	}
+
+	if (base + size > ULONG_MAX) {
+		pr_warning("Ignoring memory range 0x%lx - 0x%llx\n",
+				ULONG_MAX, base + size);
+		size = ULONG_MAX - base;
+	}
+#endif
+
 	if (base + size < phys_offset) {
 		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
 			   base, base + size);
-- 
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