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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include "utils/s2n_blob.h"
#include <ctype.h>
#include <string.h>
#include <sys/param.h>
#include "api/s2n.h"
#include "error/s2n_errno.h"
#include "utils/s2n_safety.h"
S2N_RESULT s2n_blob_validate(const struct s2n_blob *b)
{
RESULT_ENSURE_REF(b);
RESULT_DEBUG_ENSURE(S2N_IMPLIES(b->data == NULL, b->size == 0), S2N_ERR_SAFETY);
RESULT_DEBUG_ENSURE(S2N_IMPLIES(b->data == NULL, b->allocated == 0), S2N_ERR_SAFETY);
RESULT_DEBUG_ENSURE(S2N_IMPLIES(b->growable == 0, b->allocated == 0), S2N_ERR_SAFETY);
RESULT_DEBUG_ENSURE(S2N_IMPLIES(b->growable != 0, b->size <= b->allocated), S2N_ERR_SAFETY);
RESULT_DEBUG_ENSURE(S2N_MEM_IS_READABLE(b->data, b->allocated), S2N_ERR_SAFETY);
RESULT_DEBUG_ENSURE(S2N_MEM_IS_READABLE(b->data, b->size), S2N_ERR_SAFETY);
return S2N_RESULT_OK;
}
int s2n_blob_init(struct s2n_blob *b, uint8_t *data, uint32_t size)
{
POSIX_ENSURE_REF(b);
POSIX_ENSURE(S2N_MEM_IS_READABLE(data, size), S2N_ERR_SAFETY);
*b = (struct s2n_blob){ .data = data, .size = size, .allocated = 0, .growable = 0 };
POSIX_POSTCONDITION(s2n_blob_validate(b));
return S2N_SUCCESS;
}
int s2n_blob_zero(struct s2n_blob *b)
{
POSIX_PRECONDITION(s2n_blob_validate(b));
POSIX_CHECKED_MEMSET(b->data, 0, MAX(b->allocated, b->size));
POSIX_POSTCONDITION(s2n_blob_validate(b));
return S2N_SUCCESS;
}
int s2n_blob_slice(const struct s2n_blob *b, struct s2n_blob *slice, uint32_t offset, uint32_t size)
{
POSIX_PRECONDITION(s2n_blob_validate(b));
POSIX_PRECONDITION(s2n_blob_validate(slice));
uint32_t slice_size = 0;
POSIX_GUARD(s2n_add_overflow(offset, size, &slice_size));
POSIX_ENSURE(b->size >= slice_size, S2N_ERR_SIZE_MISMATCH);
slice->data = (b->data) ? (b->data + offset) : NULL;
slice->size = size;
slice->growable = 0;
slice->allocated = 0;
POSIX_POSTCONDITION(s2n_blob_validate(slice));
return S2N_SUCCESS;
}
int s2n_blob_char_to_lower(struct s2n_blob *b)
{
POSIX_PRECONDITION(s2n_blob_validate(b));
for (size_t i = 0; i < b->size; i++) {
b->data[i] = tolower(b->data[i]);
}
POSIX_POSTCONDITION(s2n_blob_validate(b));
return S2N_SUCCESS;
}
/* An inverse map from an ascii value to a hexidecimal nibble value
* accounts for all possible char values, where 255 is invalid value */
static const uint8_t hex_inverse[256] = {
/* clang-format off */
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 255, 255, 255, 255, 255, 255,
255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
/* clang-format on */
};
/* takes a hex string and writes values in the s2n_blob
* string needs to a valid hex and blob needs to be large enough */
int s2n_hex_string_to_bytes(const uint8_t *str, struct s2n_blob *blob)
{
POSIX_ENSURE_REF(str);
POSIX_PRECONDITION(s2n_blob_validate(blob));
uint32_t len_with_spaces = strlen((const char *) str);
size_t i = 0, j = 0;
while (j < len_with_spaces) {
if (str[j] == ' ') {
j++;
continue;
}
uint8_t high_nibble = hex_inverse[str[j]];
POSIX_ENSURE(high_nibble != 255, S2N_ERR_INVALID_HEX);
uint8_t low_nibble = hex_inverse[str[j + 1]];
POSIX_ENSURE(low_nibble != 255, S2N_ERR_INVALID_HEX);
POSIX_ENSURE(i < blob->size, S2N_ERR_INVALID_HEX);
blob->data[i] = high_nibble << 4 | low_nibble;
i++;
j += 2;
}
blob->size = i;
POSIX_POSTCONDITION(s2n_blob_validate(blob));
return S2N_SUCCESS;
}
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