efi_loader: initialise partition_signature memory

Zero partition_signature in the efi_device_path_hard_drive_path
structure when signature_type is 0 (no signature) as required by the
UEFI specification.

This is required so that efi_dp_match() will work as expected
when doing memcmp() comparisons.  Previously uninitialised memory
would cause it not match nodes when it should have when the signature
type was not GUID.

Corrects a problem where the loaded image protocol would not return a
device path with MEDIA_DEVICE causing the OpenBSD bootloader to fail
on rpi_3 and other targets.

v2: Also handle signature_type 1 (MBR) as described in the specification

Signed-off-by: Jonathan Gray <jsg@jsg.id.au>
Tested-by: Artturi Alm <artturi.alm@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index 0248771..9027ae8 100644 (file)
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -428,10 +428,27 @@ static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
                        hddp->partmap_type = 2;
                else
                        hddp->partmap_type = 1;
-               hddp->signature_type = desc->sig_type;
-               if (hddp->signature_type != 0)
+
+               switch (desc->sig_type) {
+               case SIG_TYPE_NONE:
+               default:
+                       hddp->signature_type = 0;
+                       memset(hddp->partition_signature, 0,
+                              sizeof(hddp->partition_signature));
+                       break;
+               case SIG_TYPE_MBR:
+                       hddp->signature_type = 1;
+                       memset(hddp->partition_signature, 0,
+                              sizeof(hddp->partition_signature));
+                       memcpy(hddp->partition_signature, &desc->mbr_sig,
+                              sizeof(desc->mbr_sig));
+                       break;
+               case SIG_TYPE_GUID:
+                       hddp->signature_type = 2;
                        memcpy(hddp->partition_signature, &desc->guid_sig,
                               sizeof(hddp->partition_signature));
+                       break;
+               }
 
                buf = &hddp[1];
        }