[U-Boot] [PATCH for 2018.05 4/8] efi_loader: fix AppendDevicePath

[Heinrich Schuchardt]

The logic of the AppendDevicePath service of the
EFI_DEVICE_PATH_UTILITIES_PROTOCOL is incorrectly implemented:

* if both paths are NULL an end node has to be returned
* if both paths are not NULL the end node of the second device path has to
  be kept

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_device_path.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
index 801c1558e5..531a754427 100644
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -263,7 +263,10 @@ struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
 {
 	struct efi_device_path *ret;
 
-	if (!dp1) {
+	if (!dp1 && !dp2) {
+		/* return an end node */
+		ret = efi_dp_dup(&END);
+	} else if (!dp1) {
 		ret = efi_dp_dup(dp2);
 	} else if (!dp2) {
 		ret = efi_dp_dup(dp1);
@@ -275,8 +278,8 @@ struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
 		if (!p)
 			return NULL;
 		memcpy(p, dp1, sz1);
-		memcpy(p + sz1, dp2, sz2);
-		memcpy(p + sz1 + sz2, &END, sizeof(END));
+		/* the end node of the second device path has to be retained */
+		memcpy(p + sz1, dp2, sz2 + sizeof(END));
 		ret = p;
 	}
 
-- 
2.14.2