1 /* SPDX-License-Identifier: BSD-3-Clause */
2
3 /*
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
vpd_decode_len(const u32 max_len,const u8 * in,u32 * length,u32 * decoded_len)9 static int vpd_decode_len(
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
vpd_decode_entry(const u32 max_len,const u8 * input_buf,u32 * consumed,const u8 ** entry,u32 * entry_len)33 static 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
vpd_decode_string(const u32 max_len,const u8 * input_buf,u32 * consumed,vpd_decode_callback callback,void * callback_arg)56 int 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;
61 u32 key_len;
62 u32 value_len;
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
77 if (vpd_decode_entry(max_len, input_buf, consumed, &key,
78 &key_len) != VPD_DECODE_OK)
79 return VPD_DECODE_FAIL;
80
81 if (vpd_decode_entry(max_len, input_buf, consumed, &value,
82 &value_len) != VPD_DECODE_OK)
83 return VPD_DECODE_FAIL;
84
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 }
96