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>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index c4cddf0cd96d..b777d8f46bd5 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;
+
+        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);