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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * vpd_decode.c
4 *
5 * Google VPD decoding routines.
6 *
7 * Copyright 2017 Google Inc.
8 */
9
10#include "vpd_decode.h"
11
12static int vpd_decode_len(const s32 max_len, const u8 *in,
13 s32 *length, s32 *decoded_len)
14{
15 u8 more;
16 int i = 0;
17
18 if (!length || !decoded_len)
19 return VPD_FAIL;
20
21 *length = 0;
22 do {
23 if (i >= max_len)
24 return VPD_FAIL;
25
26 more = in[i] & 0x80;
27 *length <<= 7;
28 *length |= in[i] & 0x7f;
29 ++i;
30 } while (more);
31
32 *decoded_len = i;
33
34 return VPD_OK;
35}
36
37int vpd_decode_string(const s32 max_len, const u8 *input_buf, s32 *consumed,
38 vpd_decode_callback callback, void *callback_arg)
39{
40 int type;
41 int res;
42 s32 key_len;
43 s32 value_len;
44 s32 decoded_len;
45 const u8 *key;
46 const u8 *value;
47
48 /* type */
49 if (*consumed >= max_len)
50 return VPD_FAIL;
51
52 type = input_buf[*consumed];
53
54 switch (type) {
55 case VPD_TYPE_INFO:
56 case VPD_TYPE_STRING:
57 (*consumed)++;
58
59 /* key */
60 res = vpd_decode_len(max_len - *consumed, &input_buf[*consumed],
61 &key_len, &decoded_len);
62 if (res != VPD_OK || *consumed + decoded_len >= max_len)
63 return VPD_FAIL;
64
65 *consumed += decoded_len;
66 key = &input_buf[*consumed];
67 *consumed += key_len;
68
69 /* value */
70 res = vpd_decode_len(max_len - *consumed, &input_buf[*consumed],
71 &value_len, &decoded_len);
72 if (res != VPD_OK || *consumed + decoded_len > max_len)
73 return VPD_FAIL;
74
75 *consumed += decoded_len;
76 value = &input_buf[*consumed];
77 *consumed += value_len;
78
79 if (type == VPD_TYPE_STRING)
80 return callback(key, key_len, value, value_len,
81 callback_arg);
82 break;
83
84 default:
85 return VPD_FAIL;
86 }
87
88 return VPD_OK;
89}