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/*
* Copyright 2022 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/core_names.h>
#include <openssl/kdf.h>
#include <openssl/params.h>
#include <openssl/err.h>
#include <openssl/proverr.h>
#include <openssl/hpke.h>
#include <openssl/sha.h>
#include <openssl/rand.h>
#include "crypto/ecx.h"
#include "internal/hpke_util.h"
#include "internal/packet.h"
#include "internal/nelem.h"
/*
* Delimiter used in OSSL_HPKE_str2suite
*/
#define OSSL_HPKE_STR_DELIMCHAR ','
/*
* table with identifier and synonym strings
* right now, there are 4 synonyms for each - a name, a hex string
* a hex string with a leading zero and a decimal string - more
* could be added but that seems like enough
*/
typedef struct {
uint16_t id;
char *synonyms[4];
} synonymttab_t;
/* max length of string we'll try map to a suite */
#define OSSL_HPKE_MAX_SUITESTR 38
/* Define HPKE labels from RFC9180 in hex for EBCDIC compatibility */
/* ASCII: "HPKE-v1", in hex for EBCDIC compatibility */
static const char LABEL_HPKEV1[] = "\x48\x50\x4B\x45\x2D\x76\x31";
/*
* Note that if additions are made to the set of IANA codepoints
* and the tables below, corresponding additions should also be
* made to the synonymtab tables a little further down so that
* OSSL_HPKE_str2suite() continues to function correctly.
*
* The canonical place to check for IANA registered codepoints
* is: https://www.iana.org/assignments/hpke/hpke.xhtml
*/
/*
* @brief table of KEMs
* See RFC9180 Section 7.1 "Table 2 KEM IDs"
*/
static const OSSL_HPKE_KEM_INFO hpke_kem_tab[] = {
#ifndef OPENSSL_NO_EC
{ OSSL_HPKE_KEM_ID_P256, "EC", OSSL_HPKE_KEMSTR_P256,
LN_sha256, SHA256_DIGEST_LENGTH, 65, 65, 32, 0xFF },
{ OSSL_HPKE_KEM_ID_P384, "EC", OSSL_HPKE_KEMSTR_P384,
LN_sha384, SHA384_DIGEST_LENGTH, 97, 97, 48, 0xFF },
{ OSSL_HPKE_KEM_ID_P521, "EC", OSSL_HPKE_KEMSTR_P521,
LN_sha512, SHA512_DIGEST_LENGTH, 133, 133, 66, 0x01 },
# ifndef OPENSSL_NO_ECX
{ OSSL_HPKE_KEM_ID_X25519, OSSL_HPKE_KEMSTR_X25519, NULL,
LN_sha256, SHA256_DIGEST_LENGTH,
X25519_KEYLEN, X25519_KEYLEN, X25519_KEYLEN, 0x00 },
{ OSSL_HPKE_KEM_ID_X448, OSSL_HPKE_KEMSTR_X448, NULL,
LN_sha512, SHA512_DIGEST_LENGTH,
X448_KEYLEN, X448_KEYLEN, X448_KEYLEN, 0x00 }
# endif
#else
{ OSSL_HPKE_KEM_ID_RESERVED, NULL, NULL, NULL, 0, 0, 0, 0, 0x00 }
#endif
};
/*
* @brief table of AEADs
* See RFC9180 Section 7.2 "Table 3 KDF IDs"
*/
static const OSSL_HPKE_AEAD_INFO hpke_aead_tab[] = {
{ OSSL_HPKE_AEAD_ID_AES_GCM_128, LN_aes_128_gcm, 16, 16,
OSSL_HPKE_MAX_NONCELEN },
{ OSSL_HPKE_AEAD_ID_AES_GCM_256, LN_aes_256_gcm, 16, 32,
OSSL_HPKE_MAX_NONCELEN },
#if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
{ OSSL_HPKE_AEAD_ID_CHACHA_POLY1305, LN_chacha20_poly1305, 16, 32,
OSSL_HPKE_MAX_NONCELEN },
#endif
{ OSSL_HPKE_AEAD_ID_EXPORTONLY, NULL, 0, 0, 0 }
};
/*
* @brief table of KDFs
* See RFC9180 Section 7.3 "Table 5 AEAD IDs"
*/
static const OSSL_HPKE_KDF_INFO hpke_kdf_tab[] = {
{ OSSL_HPKE_KDF_ID_HKDF_SHA256, LN_sha256, SHA256_DIGEST_LENGTH },
{ OSSL_HPKE_KDF_ID_HKDF_SHA384, LN_sha384, SHA384_DIGEST_LENGTH },
{ OSSL_HPKE_KDF_ID_HKDF_SHA512, LN_sha512, SHA512_DIGEST_LENGTH }
};
/**
* Synonym tables for KEMs, KDFs and AEADs: idea is to allow
* mapping strings to suites with a little flexibility in terms
* of allowing a name or a couple of forms of number (for
* the IANA codepoint). If new IANA codepoints are allocated
* then these tables should be updated at the same time as the
* others above.
*
* The function to use these is ossl_hpke_str2suite() further down
* this file and shouldn't need modification so long as the table
* sizes (i.e. allow exactly 4 synonyms) don't change.
*/
static const synonymttab_t kemstrtab[] = {
{OSSL_HPKE_KEM_ID_P256,
{OSSL_HPKE_KEMSTR_P256, "0x10", "0x10", "16" }},
{OSSL_HPKE_KEM_ID_P384,
{OSSL_HPKE_KEMSTR_P384, "0x11", "0x11", "17" }},
{OSSL_HPKE_KEM_ID_P521,
{OSSL_HPKE_KEMSTR_P521, "0x12", "0x12", "18" }},
# ifndef OPENSSL_NO_ECX
{OSSL_HPKE_KEM_ID_X25519,
{OSSL_HPKE_KEMSTR_X25519, "0x20", "0x20", "32" }},
{OSSL_HPKE_KEM_ID_X448,
{OSSL_HPKE_KEMSTR_X448, "0x21", "0x21", "33" }}
# endif
};
static const synonymttab_t kdfstrtab[] = {
{OSSL_HPKE_KDF_ID_HKDF_SHA256,
{OSSL_HPKE_KDFSTR_256, "0x1", "0x01", "1"}},
{OSSL_HPKE_KDF_ID_HKDF_SHA384,
{OSSL_HPKE_KDFSTR_384, "0x2", "0x02", "2"}},
{OSSL_HPKE_KDF_ID_HKDF_SHA512,
{OSSL_HPKE_KDFSTR_512, "0x3", "0x03", "3"}}
};
static const synonymttab_t aeadstrtab[] = {
{OSSL_HPKE_AEAD_ID_AES_GCM_128,
{OSSL_HPKE_AEADSTR_AES128GCM, "0x1", "0x01", "1"}},
{OSSL_HPKE_AEAD_ID_AES_GCM_256,
{OSSL_HPKE_AEADSTR_AES256GCM, "0x2", "0x02", "2"}},
{OSSL_HPKE_AEAD_ID_CHACHA_POLY1305,
{OSSL_HPKE_AEADSTR_CP, "0x3", "0x03", "3"}},
{OSSL_HPKE_AEAD_ID_EXPORTONLY,
{OSSL_HPKE_AEADSTR_EXP, "ff", "0xff", "255"}}
};
/* Return an object containing KEM constants associated with a EC curve name */
const OSSL_HPKE_KEM_INFO *ossl_HPKE_KEM_INFO_find_curve(const char *curve)
{
int i, sz = OSSL_NELEM(hpke_kem_tab);
for (i = 0; i < sz; ++i) {
const char *group = hpke_kem_tab[i].groupname;
if (group == NULL)
group = hpke_kem_tab[i].keytype;
if (OPENSSL_strcasecmp(curve, group) == 0)
return &hpke_kem_tab[i];
}
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
return NULL;
}
const OSSL_HPKE_KEM_INFO *ossl_HPKE_KEM_INFO_find_id(uint16_t kemid)
{
int i, sz = OSSL_NELEM(hpke_kem_tab);
/*
* this check can happen if we're in a no-ec build and there are no
* KEMS available
*/
if (kemid == OSSL_HPKE_KEM_ID_RESERVED) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
return NULL;
}
for (i = 0; i != sz; ++i) {
if (hpke_kem_tab[i].kem_id == kemid)
return &hpke_kem_tab[i];
}
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
return NULL;
}
const OSSL_HPKE_KEM_INFO *ossl_HPKE_KEM_INFO_find_random(OSSL_LIB_CTX *ctx)
{
unsigned char rval = 0;
int sz = OSSL_NELEM(hpke_kem_tab);
if (RAND_bytes_ex(ctx, &rval, sizeof(rval), 0) <= 0)
return NULL;
return &hpke_kem_tab[rval % sz];
}
const OSSL_HPKE_KDF_INFO *ossl_HPKE_KDF_INFO_find_id(uint16_t kdfid)
{
int i, sz = OSSL_NELEM(hpke_kdf_tab);
for (i = 0; i != sz; ++i) {
if (hpke_kdf_tab[i].kdf_id == kdfid)
return &hpke_kdf_tab[i];
}
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KDF);
return NULL;
}
const OSSL_HPKE_KDF_INFO *ossl_HPKE_KDF_INFO_find_random(OSSL_LIB_CTX *ctx)
{
unsigned char rval = 0;
int sz = OSSL_NELEM(hpke_kdf_tab);
if (RAND_bytes_ex(ctx, &rval, sizeof(rval), 0) <= 0)
return NULL;
return &hpke_kdf_tab[rval % sz];
}
const OSSL_HPKE_AEAD_INFO *ossl_HPKE_AEAD_INFO_find_id(uint16_t aeadid)
{
int i, sz = OSSL_NELEM(hpke_aead_tab);
for (i = 0; i != sz; ++i) {
if (
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