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review.coreboot.org / coreboot / ad6157ebdfddc39b95e388487e00cadd2bbf368b / . / src / drivers / vpd / vpd_decode.c
blob: 944e21b2a7f4612fb53d05cad270b5fdc2bfe5e1 [file] [log] [blame]
Jacob Garber10999ea62020-05-18 13:36:58 -0600[diff] [blame]1/* SPDX-License-Identifier: BSD-3-Clause */
2
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]3/*
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]4 * This is a copy from upstream:
5 * https://chromium.googlesource.com/chromiumos/platform/vpd/+/master/lib/vpd_decode.c
6 */
7#include "vpd_decode.h"
8
Hung-Te Linf6317b42019-06-12 16:59:24 +0800[diff] [blame]9static int vpd_decode_len(
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]10 const u32 max_len, const u8 *in, u32 *length, u32 *decoded_len)
11{
12 u8 more;
13 int i = 0;
14
15 if (!length || !decoded_len)
16 return VPD_DECODE_FAIL;
17
18 *length = 0;
19 do {
20 if (i >= max_len)
21 return VPD_DECODE_FAIL;
22
23 more = in[i] & 0x80;
24 *length <<= 7;
25 *length |= in[i] & 0x7f;
26 ++i;
27 } while (more);
28
29 *decoded_len = i;
30 return VPD_DECODE_OK;
31}
32
Hung-Te Linf6317b42019-06-12 16:59:24 +0800[diff] [blame]33static int vpd_decode_entry(
34 const u32 max_len, const u8 *input_buf, u32 *consumed,
35 const u8 **entry, u32 *entry_len)
36{
37 u32 decoded_len;
38
39 if (vpd_decode_len(max_len - *consumed, &input_buf[*consumed],
40 entry_len, &decoded_len) != VPD_DECODE_OK)
41 return VPD_DECODE_FAIL;
42 if (max_len - *consumed < decoded_len)
43 return VPD_DECODE_FAIL;
44
45 *consumed += decoded_len;
46 *entry = input_buf + *consumed;
47
48 /* entry_len is untrusted data and must be checked again. */
49 if (max_len - *consumed < *entry_len)
50 return VPD_DECODE_FAIL;
51
52 *consumed += *entry_len;
53 return VPD_DECODE_OK;
54}
55
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]56int vpd_decode_string(
57 const u32 max_len, const u8 *input_buf, u32 *consumed,
58 vpd_decode_callback callback, void *callback_arg)
59{
60 int type;
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]61 u32 key_len;
62 u32 value_len;
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]63 const u8 *key;
64 const u8 *value;
65
66 /* type */
67 if (*consumed >= max_len)
68 return VPD_DECODE_FAIL;
69
70 type = input_buf[*consumed];
71
72 switch (type) {
73 case VPD_TYPE_INFO:
74 case VPD_TYPE_STRING:
75 (*consumed)++;
76
Hung-Te Linf6317b42019-06-12 16:59:24 +0800[diff] [blame]77 if (vpd_decode_entry(max_len, input_buf, consumed, &key,
78 &key_len) != VPD_DECODE_OK)
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]79 return VPD_DECODE_FAIL;
80
Hung-Te Linf6317b42019-06-12 16:59:24 +0800[diff] [blame]81 if (vpd_decode_entry(max_len, input_buf, consumed, &value,
82 &value_len) != VPD_DECODE_OK)
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]83 return VPD_DECODE_FAIL;
84
Hung-Te Linc3455702019-05-27 11:02:00 +0800[diff] [blame]85 if (type == VPD_TYPE_STRING)
86 return callback(key, key_len, value, value_len,
87 callback_arg);
88 break;
89
90 default:
91 return VPD_DECODE_FAIL;
92 }
93
94 return VPD_DECODE_OK;
95}