openssl/providers/implementations/encode_decode/ml_common_codecs.c

93 lines
3.1 KiB
C

/*
* Copyright 2025 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/proverr.h>
#include "ml_common_codecs.h"
static int pref_cmp(const void *va, const void *vb)
{
const ML_COMMON_PKCS8_FMT_PREF *a = va;
const ML_COMMON_PKCS8_FMT_PREF *b = vb;
/*
* Zeros sort last, otherwise the sort is in increasing order.
*
* The preferences are small enough to ensure the comparison is transitive
* as required by qsort(3). When overflow or underflow is possible, the
* correct transitive comparison would be: (b < a) - (a < b).
*/
if (a->pref > 0 && b->pref > 0)
return a->pref - b->pref;
/* A preference of 0 is "larger" than (sorts after) any nonzero value. */
return b->pref - a->pref;
}
ML_COMMON_PKCS8_FMT_PREF *
ossl_ml_common_pkcs8_fmt_order(const char *algorithm_name,
const ML_COMMON_PKCS8_FMT *p8fmt,
const char *direction, const char *formats)
{
ML_COMMON_PKCS8_FMT_PREF *ret;
int i, count = 0;
const char *fmt = formats, *end;
const char *sep = "\t ,";
/* Reserve an extra terminal slot with fmt == NULL */
if ((ret = OPENSSL_calloc(NUM_PKCS8_FORMATS + 1, sizeof(*ret))) == NULL)
return NULL;
/* Entries that match a format will get a non-zero preference. */
for (i = 0; i < NUM_PKCS8_FORMATS; ++i) {
ret[i].fmt = &p8fmt[i];
ret[i].pref = 0;
}
/* Default to compile-time table order when none specified. */
if (formats == NULL)
return ret;
/*
* Formats are case-insensitive, separated by spaces, tabs or commas.
* Duplicate formats are allowed, the first occurence determines the order.
*/
do {
if (*(fmt += strspn(fmt, sep)) == '\0')
break;
end = fmt + strcspn(fmt, sep);
for (i = 0; i < NUM_PKCS8_FORMATS; ++i) {
/* Skip slots already selected or with a different name. */
if (ret[i].pref > 0
|| OPENSSL_strncasecmp(ret[i].fmt->p8_name,
fmt, (end - fmt)) != 0)
continue;
/* First time match */
ret[i].pref = ++count;
break;
}
fmt = end;
} while (count < NUM_PKCS8_FORMATS);
/* No formats matched, raise an error */
if (count == 0) {
OPENSSL_free(ret);
ERR_raise_data(ERR_LIB_PROV, PROV_R_ML_DSA_NO_FORMAT,
"no %s private key %s formats are enabled",
algorithm_name, direction);
return NULL;
}
/* Sort by preference, with 0's last */
qsort(ret, NUM_PKCS8_FORMATS, sizeof(*ret), pref_cmp);
/* Terminate the list at first unselected entry, perhaps reserved slot. */
ret[count].fmt = NULL;
return ret;
}