1 files changed, 74 insertions, 0 deletions
diff --git a/host/lib/extract_vmlinuz.c b/host/lib/extract_vmlinuz.c
new file mode 100644
index 00000000..81d3918e
--- /dev/null
+++ b/host/lib/extract_vmlinuz.c
@@ -0,0 +1,74 @@
+/* Copyright 2015 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Exports a vmlinuz from a kernel partition in memory.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "vboot_struct.h"
+
+
+int ExtractVmlinuz(void *kpart_data, size_t kpart_size,
+		   void **vmlinuz_out, size_t *vmlinuz_size) {
+	uint64_t now = 0;
+	VbKeyBlockHeader *keyblock = NULL;
+	VbKernelPreambleHeader *preamble = NULL;
+	uint8_t *kblob_data = NULL;
+	uint64_t kblob_size = 0;
+	uint64_t vmlinuz_header_size = 0;
+	uint64_t vmlinuz_header_address = 0;
+	uint64_t vmlinuz_header_offset = 0;
+	void *vmlinuz = NULL;
+
+	keyblock = (VbKeyBlockHeader *)kpart_data;
+	now += keyblock->key_block_size;
+	if (now > kpart_size)
+		return 1;
+
+	preamble = (VbKernelPreambleHeader *)(kpart_data + now);
+	now += preamble->preamble_size;
+	if (now > kpart_size)
+		return 1;
+
+	kblob_data = kpart_data + now;
+	kblob_size = preamble->body_signature.data_size;
+
+	if (!kblob_data || (now + kblob_size) > kpart_size)
+		return 1;
+
+	if (preamble->header_version_minor > 0) {
+		vmlinuz_header_address = preamble->vmlinuz_header_address;
+		vmlinuz_header_size = preamble->vmlinuz_header_size;
+	}
+
+	if (!vmlinuz_header_size ||
+	     kpart_data + vmlinuz_header_offset + vmlinuz_header_size > kpart_data) {
+		return 1;
+	}
+
+	// calculate the vmlinuz_header offset from
+	// the beginning of the kpart_data.  The kblob doesn't
+	// include the body_load_offset, but does include
+	// the keyblock and preamble sections.
+	vmlinuz_header_offset = vmlinuz_header_address -
+		preamble->body_load_address +
+		keyblock->key_block_size +
+		preamble->preamble_size;
+
+	vmlinuz = malloc(vmlinuz_header_size + kblob_size);
+	if (vmlinuz == NULL)
+		return 1;
+
+	memcpy(vmlinuz, kpart_data + vmlinuz_header_offset,
+	       vmlinuz_header_size);
+
+	memcpy(vmlinuz + vmlinuz_header_size, kblob_data, kblob_size);
+
+	*vmlinuz_out = vmlinuz;
+	*vmlinuz_size = vmlinuz_header_size + kblob_size;
+
+	return 0;
+}