From a752290c38b1c031859fcfbee77258cab3bc0ac1 Mon Sep 17 00:00:00 2001
From: Gary Lin <glin@suse.com>
Date: Fri, 27 Oct 2017 11:36:40 +0800
Subject: [PATCH] httpboot: Amend the device path matching rule

Originally, we check if the last 2 nodes in the device path are
IPv4()/Uri() or IPv6()/Uri() to determine whether httpboot is used or
not. However, since UEFI 2.7, the DNS node will be inserted between the
IP node and the URI node if the server provides the DNS server address.
This commit changes the matching rule to search IP node and URI node
and ignore any node between those two nodes.

Signed-off-by: Gary Lin <glin@suse.com>
---
 httpboot.c | 67 +++++++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 28 deletions(-)

diff --git a/httpboot.c b/httpboot.c
index 058704f..94299e2 100644
--- a/httpboot.c
+++ b/httpboot.c
@@ -103,10 +103,11 @@ find_httpboot (EFI_HANDLE device)
 {
 	EFI_DEVICE_PATH *unpacked;
 	EFI_DEVICE_PATH *Node;
-	EFI_DEVICE_PATH *NextNode;
 	MAC_ADDR_DEVICE_PATH *MacNode;
 	URI_DEVICE_PATH *UriNode;
 	UINTN uri_size;
+	BOOLEAN ip_found = FALSE;
+	BOOLEAN ret = FALSE;
 
 	if (uri) {
 		FreePool(uri);
@@ -126,50 +127,60 @@ find_httpboot (EFI_HANDLE device)
 	}
 	Node = unpacked;
 
-	/* Traverse the device path to find IPv4()/Uri() or IPv6()/Uri() */
+	/* Traverse the device path to find IPv4()/.../Uri() or
+	 * IPv6()/.../Uri() */
 	while (!IsDevicePathEnd(Node)) {
 		/* Save the MAC node so we can match the net card later */
 		if (DevicePathType(Node) == MESSAGING_DEVICE_PATH &&
 		    DevicePathSubType(Node) == MSG_MAC_ADDR_DP) {
 			MacNode = (MAC_ADDR_DEVICE_PATH *)Node;
-			CopyMem(&mac_addr, &MacNode->MacAddress, sizeof(EFI_MAC_ADDRESS));
-		}
-
-		if (DevicePathType(Node) == MESSAGING_DEVICE_PATH &&
-		    (DevicePathSubType(Node) == MSG_IPv4_DP ||
-		     DevicePathSubType(Node) == MSG_IPv6_DP)) {
-			/* Save the IP node so we can set up the connection later */
+			CopyMem(&mac_addr, &MacNode->MacAddress,
+				sizeof(EFI_MAC_ADDRESS));
+		} else if (DevicePathType(Node) == MESSAGING_DEVICE_PATH &&
+			   (DevicePathSubType(Node) == MSG_IPv4_DP ||
+			    DevicePathSubType(Node) == MSG_IPv6_DP)) {
+			/* Save the IP node so we can set up the connection */
+			/* later */
 			if (DevicePathSubType(Node) == MSG_IPv6_DP) {
-				CopyMem(&ip6_node, Node, sizeof(IPv6_DEVICE_PATH));
+				CopyMem(&ip6_node, Node,
+					sizeof(IPv6_DEVICE_PATH));
 				is_ip6 = TRUE;
 			} else {
-				CopyMem(&ip4_node, Node, sizeof(IPv4_DEVICE_PATH));
+				CopyMem(&ip4_node, Node,
+					sizeof(IPv4_DEVICE_PATH));
 				is_ip6 = FALSE;
 			}
 
-			Node = NextDevicePathNode(Node);
+			ip_found = TRUE;
+		} else if (ip_found == TRUE &&
+			   (DevicePathType(Node) == MESSAGING_DEVICE_PATH &&
+			    DevicePathSubType(Node) == MSG_URI_DP)) {
+			EFI_DEVICE_PATH *NextNode;
+
+			/* Check if the URI node is the last node since the */
+			/* RAMDISK node could be appended, and we don't need */
+			/* to download the second stage loader in that case. */
 			NextNode = NextDevicePathNode(Node);
-			if (DevicePathType(Node) == MESSAGING_DEVICE_PATH &&
-			    DevicePathSubType(Node) == MSG_URI_DP &&
-			    IsDevicePathEnd(NextNode)) {
-				/* Save the current URI */
-				UriNode = (URI_DEVICE_PATH *)Node;
-				uri_size = strlena(UriNode->Uri);
-				uri = AllocatePool(uri_size + 1);
-				if (!uri) {
-					perror(L"Failed to allocate uri\n");
-					return FALSE;
-				}
-				CopyMem(uri, UriNode->Uri, uri_size + 1);
-				FreePool(unpacked);
-				return TRUE;
+			if (!IsDevicePathEnd(NextNode))
+				continue;
+
+			/* Save the current URI */
+			UriNode = (URI_DEVICE_PATH *)Node;
+			uri_size = strlena(UriNode->Uri);
+			uri = AllocatePool(uri_size + 1);
+			if (!uri) {
+				perror(L"Failed to allocate uri\n");
+				goto out;
 			}
+			CopyMem(uri, UriNode->Uri, uri_size + 1);
+			ret = TRUE;
+			goto out;
 		}
 		Node = NextDevicePathNode(Node);
 	}
-
+out:
 	FreePool(unpacked);
-	return FALSE;
+	return ret;
 }
 
 static EFI_STATUS