1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
/*
* vpd_decode.c
*
* Google VPD decoding routines.
*
* Copyright 2017 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/export.h>
#include "vpd_decode.h"
static int vpd_decode_len(const u32 max_len, const u8 *in,
u32 *length, u32 *decoded_len)
{
u8 more;
int i = 0;
if (!length || !decoded_len)
return VPD_FAIL;
*length = 0;
do {
if (i >= max_len)
return VPD_FAIL;
more = in[i] & 0x80;
*length <<= 7;
*length |= in[i] & 0x7f;
++i;
} while (more);
*decoded_len = i;
return VPD_OK;
}
static int vpd_decode_entry(const u32 max_len, const u8 *input_buf,
u32 *_consumed, const u8 **entry, u32 *entry_len)
{
u32 decoded_len;
u32 consumed = *_consumed;
if (vpd_decode_len(max_len - consumed, &input_buf[consumed],
entry_len, &decoded_len) != VPD_OK)
return VPD_FAIL;
if (max_len - consumed < decoded_len)
return VPD_FAIL;
consumed += decoded_len;
*entry = input_buf + consumed;
/* entry_len is untrusted data and must be checked again. */
if (max_len - consumed < *entry_len)
return VPD_FAIL;
consumed += *entry_len;
*_consumed = consumed;
return VPD_OK;
}
int vpd_decode_string(const u32 max_len, const u8 *input_buf, u32 *consumed,
vpd_decode_callback callback, void *callback_arg)
{
int type;
u32 key_len;
u32 value_len;
const u8 *key;
const u8 *value;
/* type */
if (*consumed >= max_len)
return VPD_FAIL;
type = input_buf[*consumed];
switch (type) {
case VPD_TYPE_INFO:
case VPD_TYPE_STRING:
(*consumed)++;
if (vpd_decode_entry(max_len, input_buf, consumed, &key,
&key_len) != VPD_OK)
return VPD_FAIL;
if (vpd_decode_entry(max_len, input_buf, consumed, &value,
&value_len) != VPD_OK)
return VPD_FAIL;
if (type == VPD_TYPE_STRING)
return callback(key, key_len, value, value_len,
callback_arg);
break;
default:
return VPD_FAIL;
}
return VPD_OK;
}
|
