1 /* Copyright 2015 The Chromium OS Authors. All rights reserved.
2  * Use of this source code is governed by a BSD-style license that can be
3  * found in the LICENSE file.
4  *
5  * Exports a vmlinuz from a kernel partition in memory.
6  */
7 
8 #include <stdlib.h>
9 #include <string.h>
10 
11 #include "vboot_struct.h"
12 
13 
ExtractVmlinuz(void * kpart_data,size_t kpart_size,void ** vmlinuz_out,size_t * vmlinuz_size)14 int ExtractVmlinuz(void *kpart_data, size_t kpart_size,
15 		   void **vmlinuz_out, size_t *vmlinuz_size) {
16 	uint64_t now = 0;
17 	VbKeyBlockHeader *keyblock = NULL;
18 	VbKernelPreambleHeader *preamble = NULL;
19 	uint8_t *kblob_data = NULL;
20 	uint64_t kblob_size = 0;
21 	uint64_t vmlinuz_header_size = 0;
22 	uint64_t vmlinuz_header_address = 0;
23 	uint64_t vmlinuz_header_offset = 0;
24 	void *vmlinuz = NULL;
25 
26 	keyblock = (VbKeyBlockHeader *)kpart_data;
27 	now += keyblock->key_block_size;
28 	if (now > kpart_size)
29 		return 1;
30 
31 	preamble = (VbKernelPreambleHeader *)(kpart_data + now);
32 	now += preamble->preamble_size;
33 	if (now > kpart_size)
34 		return 1;
35 
36 	kblob_data = kpart_data + now;
37 	kblob_size = preamble->body_signature.data_size;
38 
39 	if (!kblob_data || (now + kblob_size) > kpart_size)
40 		return 1;
41 
42 	if (preamble->header_version_minor > 0) {
43 		vmlinuz_header_address = preamble->vmlinuz_header_address;
44 		vmlinuz_header_size = preamble->vmlinuz_header_size;
45 	}
46 
47 	if (!vmlinuz_header_size ||
48 	     kpart_data + vmlinuz_header_offset + vmlinuz_header_size > kpart_data) {
49 		return 1;
50 	}
51 
52 	// calculate the vmlinuz_header offset from
53 	// the beginning of the kpart_data.  The kblob doesn't
54 	// include the body_load_offset, but does include
55 	// the keyblock and preamble sections.
56 	vmlinuz_header_offset = vmlinuz_header_address -
57 		preamble->body_load_address +
58 		keyblock->key_block_size +
59 		preamble->preamble_size;
60 
61 	vmlinuz = malloc(vmlinuz_header_size + kblob_size);
62 	if (vmlinuz == NULL)
63 		return 1;
64 
65 	memcpy(vmlinuz, kpart_data + vmlinuz_header_offset,
66 	       vmlinuz_header_size);
67 
68 	memcpy(vmlinuz + vmlinuz_header_size, kblob_data, kblob_size);
69 
70 	*vmlinuz_out = vmlinuz;
71 	*vmlinuz_size = vmlinuz_header_size + kblob_size;
72 
73 	return 0;
74 }
75