1 /*
2 * Copyright 2025 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <string.h>
11 #include <openssl/crypto.h>
12 #include <openssl/err.h>
13 #include <openssl/proverr.h>
14 #include "ml_common_codecs.h"
15
pref_cmp(const void * va,const void * vb)16 static int pref_cmp(const void *va, const void *vb)
17 {
18 const ML_COMMON_PKCS8_FMT_PREF *a = va;
19 const ML_COMMON_PKCS8_FMT_PREF *b = vb;
20
21 /*
22 * Zeros sort last, otherwise the sort is in increasing order.
23 *
24 * The preferences are small enough to ensure the comparison is transitive
25 * as required by qsort(3). When overflow or underflow is possible, the
26 * correct transitive comparison would be: (b < a) - (a < b).
27 */
28 if (a->pref > 0 && b->pref > 0)
29 return a->pref - b->pref;
30 /* A preference of 0 is "larger" than (sorts after) any nonzero value. */
31 return b->pref - a->pref;
32 }
33
34 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)35 ossl_ml_common_pkcs8_fmt_order(const char *algorithm_name,
36 const ML_COMMON_PKCS8_FMT *p8fmt,
37 const char *direction, const char *formats)
38 {
39 ML_COMMON_PKCS8_FMT_PREF *ret;
40 int i, count = 0;
41 const char *fmt = formats, *end;
42 const char *sep = "\t ,";
43
44 /* Reserve an extra terminal slot with fmt == NULL */
45 if ((ret = OPENSSL_zalloc((NUM_PKCS8_FORMATS + 1) * sizeof(*ret))) == NULL)
46 return NULL;
47
48 /* Entries that match a format will get a non-zero preference. */
49 for (i = 0; i < NUM_PKCS8_FORMATS; ++i) {
50 ret[i].fmt = &p8fmt[i];
51 ret[i].pref = 0;
52 }
53
54 /* Default to compile-time table order when none specified. */
55 if (formats == NULL)
56 return ret;
57
58 /*
59 * Formats are case-insensitive, separated by spaces, tabs or commas.
60 * Duplicate formats are allowed, the first occurence determines the order.
61 */
62 do {
63 if (*(fmt += strspn(fmt, sep)) == '\0')
64 break;
65 end = fmt + strcspn(fmt, sep);
66 for (i = 0; i < NUM_PKCS8_FORMATS; ++i) {
67 /* Skip slots already selected or with a different name. */
68 if (ret[i].pref > 0
69 || OPENSSL_strncasecmp(ret[i].fmt->p8_name,
70 fmt, (end - fmt)) != 0)
71 continue;
72 /* First time match */
73 ret[i].pref = ++count;
74 break;
75 }
76 fmt = end;
77 } while (count < NUM_PKCS8_FORMATS);
78
79 /* No formats matched, raise an error */
80 if (count == 0) {
81 OPENSSL_free(ret);
82 ERR_raise_data(ERR_LIB_PROV, PROV_R_ML_DSA_NO_FORMAT,
83 "no %s private key %s formats are enabled",
84 algorithm_name, direction);
85 return NULL;
86 }
87 /* Sort by preference, with 0's last */
88 qsort(ret, NUM_PKCS8_FORMATS, sizeof(*ret), pref_cmp);
89 /* Terminate the list at first unselected entry, perhaps reserved slot. */
90 ret[count].fmt = NULL;
91 return ret;
92 }
93