efi_loader: only check size if EFI_DT_APPLY_FIXUPS

In the implementation of the EFI_DT_FIXUP_PROTOCOL:

* Only check the buffer size when EFI_DT_APPLY_FIXUPS is set.
* In this case the field totalsize of the device-tree may not exceed the
  buffer size.
* Install device-tree only if EFI_DT_INSTALL_TABLE is set.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/lib/efi_loader/efi_dt_fixup.c b/lib/efi_loader/efi_dt_fixup.c
index 3850ab3b0fe655cd3463f11b4143c064fe90a1c7..6de57b84d2057390c6f17c6c413420022a474b0c 100644 (file)
--- a/lib/efi_loader/efi_dt_fixup.c
+++ b/lib/efi_loader/efi_dt_fixup.c
@@ -110,6 +110,7 @@ efi_dt_fixup(struct efi_dt_fixup_protocol *this, void *dtb,
 {
        efi_status_t ret;
        size_t required_size;
+       size_t total_size;
        bootm_headers_t img = { 0 };
 
        EFI_ENTRY("%p, %p, %p, %d", this, dtb, buffer_size, flags);
@@ -124,20 +125,20 @@ efi_dt_fixup(struct efi_dt_fixup_protocol *this, void *dtb,
                goto out;
        }
        if (flags & EFI_DT_APPLY_FIXUPS) {
+               /* Check size */
                required_size = fdt_off_dt_strings(dtb) +
                                fdt_size_dt_strings(dtb) +
                                0x3000;
-       } else {
-               required_size = fdt_totalsize(dtb);
-       }
-       if (required_size > *buffer_size) {
-               *buffer_size = required_size;
-               ret = EFI_BUFFER_TOO_SMALL;
-               goto out;
-       }
-       fdt_set_totalsize(dtb, *buffer_size);
+               total_size = fdt_totalsize(dtb);
+               if (required_size < total_size)
+                       required_size = total_size;
+               if (required_size > *buffer_size) {
+                       *buffer_size = required_size;
+                       ret = EFI_BUFFER_TOO_SMALL;
+                       goto out;
+               }
 
-       if (flags & EFI_DT_APPLY_FIXUPS) {
+               fdt_set_totalsize(dtb, *buffer_size);
                if (image_setup_libfdt(&img, dtb, 0, NULL)) {
                        log_err("failed to process device tree\n");
                        ret = EFI_INVALID_PARAMETER;
@@ -147,10 +148,10 @@ efi_dt_fixup(struct efi_dt_fixup_protocol *this, void *dtb,
        if (flags & EFI_DT_RESERVE_MEMORY)
                efi_carve_out_dt_rsv(dtb);
 
-       if (EFI_DT_INSTALL_TABLE) {
+       if (flags & EFI_DT_INSTALL_TABLE) {
                ret = efi_install_configuration_table(&efi_guid_fdt, dtb);
                if (ret != EFI_SUCCESS) {
-                       log_err("ERROR: failed to install device tree\n");
+                       log_err("failed to install device tree\n");
                        goto out;
                }
        }