of: Check for phys_addr_t overflows in early_init_dt_add_memory_arch

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@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index c4cddf0..b777d8f 100644 (file)
--- 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;
+
+       if (sizeof(phys_addr_t) < sizeof(u64)) {
+               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;
+               }
+       }
+
        if (base + size < phys_offset) {
                pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
                           base, base + size);