1 /*
2  * Copyright (c) 2021 - 2022, Intel Corporation.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  *    * Redistributions of source code must retain the above copyright
9  *      notice, this list of conditions and the following disclaimer.
10  *    * Redistributions in binary form must reproduce the above copyright
11  *      notice, this list of conditions and the following disclaimer
12  *      in the documentation and/or other materials provided with the
13  *      distribution.
14  *    * Neither the name of Intel Corporation nor the names of its
15  *      contributors may be used to endorse or promote products
16  *      derived from this software without specific prior written
17  *      permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
25  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
26  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
28  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
30  * OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #include <efi.h>
34 #include <efilib.h>
35 #include "boot.h"
36 #include "stdlib.h"
37 #include "multiboot.h"
38 
39 /**
40  * @brief Search the first len bytes in buffer for multiboot1 header.
41  *
42  * @param[in] buffer Buffer to be searched
43  * @param[in] len    Search length
44  *
45  * @return A pointer to the multiboot1 header if found. NULL otherwise.
46  */
find_mb1header(const UINT8 * buffer,uint64_t len)47 const struct multiboot_header *find_mb1header(const UINT8 *buffer, uint64_t len)
48 {
49 	const struct multiboot_header *header;
50 
51 	for (header = (struct multiboot_header *)buffer;
52 		((char *)header <= (char *)buffer + len - 12);
53 		header = (struct multiboot_header *)((char *)header + MULTIBOOT_HEADER_ALIGN))
54 	{
55 		if (header->mh_magic == MULTIBOOT_HEADER_MAGIC &&
56 			!(header->mh_magic + header->mh_flags + header->mh_checksum))
57 			return header;
58 	}
59 
60 	return NULL;
61 }
62 
63 /**
64  * @brief Search the first len bytes in buffer for multiboot2 header.
65  *
66  * @param[in] buffer Buffer to be searched
67  * @param[in] len    Search length
68  *
69  * @return A pointer to the multiboot2 header if found. NULL otherwise.
70  */
find_mb2header(const UINT8 * buffer,uint64_t len)71 const struct multiboot2_header *find_mb2header(const UINT8 *buffer, uint64_t len)
72 {
73 	const struct multiboot2_header *header;
74 
75 	for (header = (const struct multiboot2_header *)buffer;
76 		((char *)header <= (char *)buffer + len - 12);
77 		header = (struct multiboot2_header *)((uint64_t)header + MULTIBOOT2_HEADER_ALIGN / 4))
78 	{
79 		if (header->magic == MULTIBOOT2_HEADER_MAGIC &&
80 			!(header->magic + header->architecture + header->header_length + header->checksum) &&
81 			header->architecture == MULTIBOOT2_ARCHITECTURE_I386)
82 			return header;
83 	}
84 
85 	return NULL;
86 }
87 
88 /**
89  * @brief Parse the multiboot2 header and return a list of pointers to the header tags.
90  *
91  * @param[in]  header     Multiboot2 header to be parsed.
92  * @param[out] hv_tags    An hv_mb2header_tag_list struct that contains pointers to all possible
93  *                        tags in a multiboot2 header. If a field in this struct is not NULL, it
94  *                        means the tag was found in the given header. NULL otherwise.
95  *
96  * @return 0 on success. -1 on error.
97  */
parse_mb2header(const struct multiboot2_header * header,struct hv_mb2header_tag_list * hv_tags)98 int parse_mb2header(const struct multiboot2_header *header, struct hv_mb2header_tag_list *hv_tags)
99 {
100 	struct multiboot2_header_tag *tag;
101 
102 	memset(hv_tags, 0, sizeof(struct hv_mb2header_tag_list));
103 
104 	for (tag = (struct multiboot2_header_tag *)(header + 1);
105 		tag->type != MULTIBOOT2_TAG_TYPE_END;
106 		tag = (struct multiboot2_header_tag *)((uint32_t *)tag + ALIGN_UP(tag->size, MULTIBOOT2_TAG_ALIGN) / 4))
107 	{
108 		switch (tag->type) {
109 			case MULTIBOOT2_HEADER_TAG_INFORMATION_REQUEST:
110 				/* Ignored. Currently we didn't support all categories of requested information,
111 				 * only the part that ACRN requests. So we don't parse the requests here. */
112 				break;
113 
114 			case MULTIBOOT2_HEADER_TAG_ADDRESS:
115 				hv_tags->addr = (struct multiboot2_header_tag_address *)tag;
116 				break;
117 
118 			case MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS:
119 				hv_tags->entry = (struct multiboot2_header_tag_entry_address *)tag;
120 				break;
121 
122 			case MULTIBOOT2_HEADER_TAG_RELOCATABLE:
123 				hv_tags->reloc = (struct multiboot2_header_tag_relocatable *)tag;
124 				break;
125 
126 			default:
127 				Print(L"Unsupported multiboot2 tag type: %d\n", tag->type);
128 				return -1;
129 		}
130 	}
131 
132 	if (hv_tags->addr && !hv_tags->entry)
133 		return -1;
134 
135 	return 0;
136 }
137