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/*
* Copyright 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* This is a copy from upstream:
* https://chromium.googlesource.com/chromiumos/platform/vpd/+/master/lib/vpd_decode.c
*/
#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_DECODE_FAIL;
*length = 0;
do {
if (i >= max_len)
return VPD_DECODE_FAIL;
more = in[i] & 0x80;
*length <<= 7;
*length |= in[i] & 0x7f;
++i;
} while (more);
*decoded_len = i;
return VPD_DECODE_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;
if (vpd_decode_len(max_len - *consumed, &input_buf[*consumed],
entry_len, &decoded_len) != VPD_DECODE_OK)
return VPD_DECODE_FAIL;
if (max_len - *consumed < decoded_len)
return VPD_DECODE_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_DECODE_FAIL;
*consumed += *entry_len;
return VPD_DECODE_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_DECODE_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_DECODE_OK)
return VPD_DECODE_FAIL;
if (vpd_decode_entry(max_len, input_buf, consumed, &value,
&value_len) != VPD_DECODE_OK)
return VPD_DECODE_FAIL;
if (type == VPD_TYPE_STRING)
return callback(key, key_len, value, value_len,
callback_arg);
break;
default:
return VPD_DECODE_FAIL;
}
return VPD_DECODE_OK;
}
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