/src/openssl36/crypto/cms/cms_kari.c

Source
/*
 * Copyright 2013-2026 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 "internal/cryptlib.h"
#include <openssl/asn1t.h>
#include <openssl/pem.h>
#include <openssl/x509v3.h>
#include <openssl/err.h>
#include <openssl/cms.h>
#include <openssl/aes.h>
#include "cms_local.h"
#include "crypto/asn1.h"

/* Key Agreement Recipient Info (KARI) routines */

int CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri,
    X509_ALGOR **palg,
    ASN1_OCTET_STRING **pukm)
{
    if (ri->type != CMS_RECIPINFO_AGREE) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
        return 0;
    }
    if (palg)
        *palg = ri->d.kari->keyEncryptionAlgorithm;
    if (pukm)
        *pukm = ri->d.kari->ukm;
    return 1;
}

/* Retrieve recipient encrypted keys from a kari */

STACK_OF(CMS_RecipientEncryptedKey)
*CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo *ri)
{
    if (ri->type != CMS_RECIPINFO_AGREE) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
        return NULL;
    }
    return ri->d.kari->recipientEncryptedKeys;
}

int CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri,
    X509_ALGOR **pubalg,
    ASN1_BIT_STRING **pubkey,
    ASN1_OCTET_STRING **keyid,
    X509_NAME **issuer,
    ASN1_INTEGER **sno)
{
    CMS_OriginatorIdentifierOrKey *oik;

    if (ri->type != CMS_RECIPINFO_AGREE) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
        return 0;
    }
    oik = ri->d.kari->originator;
    if (issuer)
        *issuer = NULL;
    if (sno)
        *sno = NULL;
    if (keyid)
        *keyid = NULL;
    if (pubalg)
        *pubalg = NULL;
    if (pubkey)
        *pubkey = NULL;
    if (oik->type == CMS_OIK_ISSUER_SERIAL) {
        if (issuer)
            *issuer = oik->d.issuerAndSerialNumber->issuer;
        if (sno)
            *sno = oik->d.issuerAndSerialNumber->serialNumber;
    } else if (oik->type == CMS_OIK_KEYIDENTIFIER) {
        if (keyid)
            *keyid = oik->d.subjectKeyIdentifier;
    } else if (oik->type == CMS_OIK_PUBKEY) {
        if (pubalg)
            *pubalg = oik->d.originatorKey->algorithm;
        if (pubkey)
            *pubkey = oik->d.originatorKey->publicKey;
    } else
        return 0;
    return 1;
}

int CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo *ri, X509 *cert)
{
    CMS_OriginatorIdentifierOrKey *oik;

    if (ri->type != CMS_RECIPINFO_AGREE) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
        return -2;
    }
    oik = ri->d.kari->originator;
    if (oik->type == CMS_OIK_ISSUER_SERIAL)
        return ossl_cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);
    else if (oik->type == CMS_OIK_KEYIDENTIFIER)
        return ossl_cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);
    return -1;
}

int CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,
    ASN1_OCTET_STRING **keyid,
    ASN1_GENERALIZEDTIME **tm,
    CMS_OtherKeyAttribute **other,
    X509_NAME **issuer, ASN1_INTEGER **sno)
{
    CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;

    if (rid->type == CMS_REK_ISSUER_SERIAL) {
        if (issuer)
            *issuer = rid->d.issuerAndSerialNumber->issuer;
        if (sno)
            *sno = rid->d.issuerAndSerialNumber->serialNumber;
        if (keyid)
            *keyid = NULL;
        if (tm)
            *tm = NULL;
        if (other)
            *other = NULL;
    } else if (rid->type == CMS_REK_KEYIDENTIFIER) {
        if (keyid)
            *keyid = rid->d.rKeyId->subjectKeyIdentifier;
        if (tm)
            *tm = rid->d.rKeyId->date;
        if (other)
            *other = rid->d.rKeyId->other;
        if (issuer)
            *issuer = NULL;
        if (sno)
            *sno = NULL;
    } else
        return 0;
    return 1;
}

int CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek,
    X509 *cert)
{
    CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;

    if (rid->type == CMS_REK_ISSUER_SERIAL)
        return ossl_cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);
    else if (rid->type == CMS_REK_KEYIDENTIFIER)
        return ossl_cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier,
            cert);
    else
        return -1;
}

int CMS_RecipientInfo_kari_set0_pkey_and_peer(CMS_RecipientInfo *ri,
    EVP_PKEY *pk, X509 *peer)
{
    EVP_PKEY_CTX *pctx;
    CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;

    EVP_PKEY_CTX_free(kari->pctx);
    kari->pctx = NULL;
    if (pk == NULL)
        return 1;

    pctx = EVP_PKEY_CTX_new_from_pkey(ossl_cms_ctx_get0_libctx(kari->cms_ctx),
        pk,
        ossl_cms_ctx_get0_propq(kari->cms_ctx));
    if (pctx == NULL || EVP_PKEY_derive_init(pctx) <= 0)
        goto err;

    if (peer != NULL) {
        EVP_PKEY *pub_pkey = X509_get0_pubkey(peer);

        if (EVP_PKEY_derive_set_peer(pctx, pub_pkey) <= 0)
            goto err;
    }

    kari->pctx = pctx;
    return 1;
err:
    EVP_PKEY_CTX_free(pctx);
    return 0;
}

int CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pk)
{
    return CMS_RecipientInfo_kari_set0_pkey_and_peer(ri, pk, NULL);
}

EVP_CIPHER_CTX *CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri)
{
    if (ri->type == CMS_RECIPINFO_AGREE)
        return ri->d.kari->ctx;
    return NULL;
}

/*
 * Derive KEK and decrypt/encrypt with it to produce either the original CEK
 * or the encrypted CEK.
 */

static int cms_kek_cipher(unsigned char **pout, size_t *poutlen,
    const unsigned char *in, size_t inlen,
    CMS_KeyAgreeRecipientInfo *kari, int enc)
{
    /* Key encryption key */
    unsigned char kek[EVP_MAX_KEY_LENGTH];
    size_t keklen;
    int rv = 0;
    unsigned char *out = NULL;
    size_t out_alloc_len = 0;
    int outlen;
    size_t outsize;

    keklen = EVP_CIPHER_CTX_get_key_length(kari->ctx);
    if (keklen > EVP_MAX_KEY_LENGTH || inlen > INT_MAX)
        return 0;
    /* Derive KEK */
    if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)
        goto err;
    /* Set KEK in context */
    if (!EVP_CipherInit_ex(kari->ctx, NULL, NULL, kek, NULL, enc))
        goto err;
    /* obtain output length of ciphered key */
    if (!EVP_CipherUpdate(kari->ctx, NULL, &outlen, in, (int)inlen))
        goto err;
    /*
     * On its integrity-failure paths that primitive writes and cleanses up to
     * inlen bytes of the output buffer. Size the buffer for that worst case so
     * a failed unwrap cannot write past the allocation.
     */
    outsize = (size_t)outlen < inlen ? inlen : (size_t)outlen;
    out = OPENSSL_malloc(outsize);
    if (out == NULL)
        goto err;
    out_alloc_len = (size_t)outlen;
    if (!EVP_CipherUpdate(kari->ctx, out, &outlen, in, (int)inlen))
        goto err;
    *pout = out;
    *poutlen = (size_t)outlen;
    rv = 1;

err:
    OPENSSL_cleanse(kek, keklen);
    if (!rv)
        OPENSSL_clear_free(out, out_alloc_len);
    EVP_CIPHER_CTX_reset(kari->ctx);
    /* FIXME: WHY IS kari->pctx freed here?  /RL */
    EVP_PKEY_CTX_free(kari->pctx);
    kari->pctx = NULL;
    return rv;
}

int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms,
    CMS_RecipientInfo *ri,
    CMS_RecipientEncryptedKey *rek)
{
    int rv = 0;
    unsigned char *enckey = NULL, *cek = NULL;
    size_t enckeylen;
    size_t ceklen;
    CMS_EncryptedContentInfo *ec;

    enckeylen = rek->encryptedKey->length;
    enckey = rek->encryptedKey->data;
    /* Setup all parameters to derive KEK */
    if (!ossl_cms_env_asn1_ctrl(ri, 1))
        goto err;
    /* Attempt to decrypt CEK */
    if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))
        goto err;
    ec = ossl_cms_get0_env_enc_content(cms);
    OPENSSL_clear_free(ec->key, ec->keylen);
    ec->key = cek;
    ec->keylen = ceklen;
    cek = NULL;
    rv = 1;
err:
    OPENSSL_free(cek);
    return rv;
}

/* Create ephemeral key and initialise context based on it */
static int cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari,
    EVP_PKEY *pk)
{
    EVP_PKEY_CTX *pctx = NULL;
    EVP_PKEY *ekey = NULL;
    int rv = 0;
    const CMS_CTX *ctx = kari->cms_ctx;
    OSSL_LIB_CTX *libctx = ossl_cms_ctx_get0_libctx(ctx);
    const char *propq = ossl_cms_ctx_get0_propq(ctx);

    pctx = EVP_PKEY_CTX_new_from_pkey(libctx, pk, propq);
    if (pctx == NULL)
        goto err;
    if (EVP_PKEY_keygen_init(pctx) <= 0)
        goto err;
    if (EVP_PKEY_keygen(pctx, &ekey) <= 0)
        goto err;
    EVP_PKEY_CTX_free(pctx);
    pctx = EVP_PKEY_CTX_new_from_pkey(libctx, ekey, propq);
    if (pctx == NULL)
        goto err;
    if (EVP_PKEY_derive_init(pctx) <= 0)
        goto err;
    kari->pctx = pctx;
    rv = 1;
err:
    if (!rv)
        EVP_PKEY_CTX_free(pctx);
    EVP_PKEY_free(ekey);
    return rv;
}

/* Set originator private key and initialise context based on it */
static int cms_kari_set_originator_private_key(CMS_KeyAgreeRecipientInfo *kari,
    EVP_PKEY *originatorPrivKey)
{
    EVP_PKEY_CTX *pctx = NULL;
    int rv = 0;
    const CMS_CTX *ctx = kari->cms_ctx;

    pctx = EVP_PKEY_CTX_new_from_pkey(ossl_cms_ctx_get0_libctx(ctx),
        originatorPrivKey,
        ossl_cms_ctx_get0_propq(ctx));
    if (pctx == NULL)
        goto err;
    if (EVP_PKEY_derive_init(pctx) <= 0)
        goto err;

    kari->pctx = pctx;
    rv = 1;
err:
    if (rv == 0)
        EVP_PKEY_CTX_free(pctx);
    return rv;
}

/* Initialise a kari based on passed certificate and key */

int ossl_cms_RecipientInfo_kari_init(CMS_RecipientInfo *ri, X509 *recip,
    EVP_PKEY *recipPubKey, X509 *originator,
    EVP_PKEY *originatorPrivKey,
    unsigned int flags, const CMS_CTX *ctx)
{
    CMS_KeyAgreeRecipientInfo *kari;
    CMS_RecipientEncryptedKey *rek = NULL;

    ri->d.kari = M_ASN1_new_of(CMS_KeyAgreeRecipientInfo);
    if (ri->d.kari == NULL)
        return 0;
    ri->encoded_type = ri->type = CMS_RECIPINFO_AGREE;

    kari = ri->d.kari;
    kari->version = 3;
    kari->cms_ctx = ctx;

    rek = M_ASN1_new_of(CMS_RecipientEncryptedKey);
    if (rek == NULL)
        return 0;

    if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {
        M_ASN1_free_of(rek, CMS_RecipientEncryptedKey);
        return 0;
    }

    if (flags & CMS_USE_KEYID) {
        rek->rid->type = CMS_REK_KEYIDENTIFIER;
        rek->rid->d.rKeyId = M_ASN1_new_of(CMS_RecipientKeyIdentifier);
        if (rek->rid->d.rKeyId == NULL)
            return 0;
        if (!ossl_cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))
            return 0;
    } else {
        rek->rid->type = CMS_REK_ISSUER_SERIAL;
        if (!ossl_cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))
            return 0;
    }

    if (originatorPrivKey == NULL && originator == NULL) {
        /* Create ephemeral key */
        if (!cms_kari_create_ephemeral_key(kari, recipPubKey))
            return 0;
    } else {
        /* Use originator key */
        CMS_OriginatorIdentifierOrKey *oik = ri->d.kari->originator;

        if (originatorPrivKey == NULL || originator == NULL)
            return 0;

        if (flags & CMS_USE_ORIGINATOR_KEYID) {
            oik->type = CMS_OIK_KEYIDENTIFIER;
            oik->d.subjectKeyIdentifier = ASN1_OCTET_STRING_new();
            if (oik->d.subjectKeyIdentifier == NULL)
                return 0;
            if (!ossl_cms_set1_keyid(&oik->d.subjectKeyIdentifier, originator))
                return 0;
        } else {
            oik->type = CMS_REK_ISSUER_SERIAL;
            if (!ossl_cms_set1_ias(&oik->d.issuerAndSerialNumber, originator))
                return 0;
        }

        if (!cms_kari_set_originator_private_key(kari, originatorPrivKey))
            return 0;
    }

    if (!EVP_PKEY_up_ref(recipPubKey))
        return 0;

    rek->pkey = recipPubKey;
    return 1;
}

/* Encrypt content key in key agreement recipient info */

int ossl_cms_RecipientInfo_kari_encrypt(const CMS_ContentInfo *cms,
    CMS_RecipientInfo *ri)
{
    CMS_KeyAgreeRecipientInfo *kari;
    CMS_EncryptedContentInfo *ec;
    CMS_RecipientEncryptedKey *rek;
    STACK_OF(CMS_RecipientEncryptedKey) *reks;
    int i;

    if (ri->type != CMS_RECIPINFO_AGREE) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
        return 0;
    }
    kari = ri->d.kari;
    reks = kari->recipientEncryptedKeys;
    ec = ossl_cms_get0_env_enc_content(cms);
    /* Initialise wrap algorithm parameters */
    if (!ossl_cms_RecipientInfo_wrap_init(ri, ec->cipher))
        return 0;
    /*
     * If no originator key set up initialise for ephemeral key the public key
     * ASN1 structure will set the actual public key value.
     */
    if (kari->originator->type == -1) {
        CMS_OriginatorIdentifierOrKey *oik = kari->originator;
        oik->type = CMS_OIK_PUBKEY;
        oik->d.originatorKey = M_ASN1_new_of(CMS_OriginatorPublicKey);
        if (!oik->d.originatorKey)
            return 0;
    } else {
        /*
         * Currently it is not possible to get public key as it is not stored
         * during kari initialization.
         */
        ERR_raise(ERR_LIB_CMS, CMS_R_ERROR_UNSUPPORTED_STATIC_KEY_AGREEMENT);
        return 0;
    }
    /* Initialise KDF algorithm */
    if (!ossl_cms_env_asn1_ctrl(ri, 0))
        return 0;
    /* For each rek, derive KEK, encrypt CEK */
    for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {
        unsigned char *enckey;
        size_t enckeylen;
        rek = sk_CMS_RecipientEncryptedKey_value(reks, i);
        if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)
            return 0;
        if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,
                kari, 1))
            return 0;
        ASN1_STRING_set0(rek->encryptedKey, enckey, (int)enckeylen);
    }

    return 1;
}

Coverage Report

Created: 2026-09-12 06:55

Line	Count	Source
1		/*
2		* Copyright 2013-2026 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 "internal/cryptlib.h"
11		#include <openssl/asn1t.h>
12		#include <openssl/pem.h>
13		#include <openssl/x509v3.h>
14		#include <openssl/err.h>
15		#include <openssl/cms.h>
16		#include <openssl/aes.h>
17		#include "cms_local.h"
18		#include "crypto/asn1.h"
19
20		/* Key Agreement Recipient Info (KARI) routines */
21
22		int CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri,
23		X509_ALGOR **palg,
24		ASN1_OCTET_STRING **pukm)
25	0	{
26	0	if (ri->type != CMS_RECIPINFO_AGREE) {
27	0	ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
28	0	return 0;
29	0	}
30	0	if (palg)
31	0	*palg = ri->d.kari->keyEncryptionAlgorithm;
32	0	if (pukm)
33	0	*pukm = ri->d.kari->ukm;
34	0	return 1;
35	0	}
36
37		/* Retrieve recipient encrypted keys from a kari */
38
39		STACK_OF(CMS_RecipientEncryptedKey)
40		CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo ri)
41	0	{
42	0	if (ri->type != CMS_RECIPINFO_AGREE) {
43	0	ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
44	0	return NULL;
45	0	}
46	0	return ri->d.kari->recipientEncryptedKeys;
47	0	}
48
49		int CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri,
50		X509_ALGOR **pubalg,
51		ASN1_BIT_STRING **pubkey,
52		ASN1_OCTET_STRING **keyid,
53		X509_NAME **issuer,
54		ASN1_INTEGER **sno)
55	0	{
56	0	CMS_OriginatorIdentifierOrKey *oik;
57
58	0	if (ri->type != CMS_RECIPINFO_AGREE) {
59	0	ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
60	0	return 0;
61	0	}
62	0	oik = ri->d.kari->originator;
63	0	if (issuer)
64	0	*issuer = NULL;
65	0	if (sno)
66	0	*sno = NULL;
67	0	if (keyid)
68	0	*keyid = NULL;
69	0	if (pubalg)
70	0	*pubalg = NULL;
71	0	if (pubkey)
72	0	*pubkey = NULL;
73	0	if (oik->type == CMS_OIK_ISSUER_SERIAL) {
74	0	if (issuer)
75	0	*issuer = oik->d.issuerAndSerialNumber->issuer;
76	0	if (sno)
77	0	*sno = oik->d.issuerAndSerialNumber->serialNumber;
78	0	} else if (oik->type == CMS_OIK_KEYIDENTIFIER) {
79	0	if (keyid)
80	0	*keyid = oik->d.subjectKeyIdentifier;
81	0	} else if (oik->type == CMS_OIK_PUBKEY) {
82	0	if (pubalg)
83	0	*pubalg = oik->d.originatorKey->algorithm;
84	0	if (pubkey)
85	0	*pubkey = oik->d.originatorKey->publicKey;
86	0	} else
87	0	return 0;
88	0	return 1;
89	0	}
90
91		int CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo ri, X509 cert)
92	0	{
93	0	CMS_OriginatorIdentifierOrKey *oik;
94
95	0	if (ri->type != CMS_RECIPINFO_AGREE) {
96	0	ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
97	0	return -2;
98	0	}
99	0	oik = ri->d.kari->originator;
100	0	if (oik->type == CMS_OIK_ISSUER_SERIAL)
101	0	return ossl_cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);
102	0	else if (oik->type == CMS_OIK_KEYIDENTIFIER)
103	0	return ossl_cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);
104	0	return -1;
105	0	}
106
107		int CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,
108		ASN1_OCTET_STRING **keyid,
109		ASN1_GENERALIZEDTIME **tm,
110		CMS_OtherKeyAttribute **other,
111		X509_NAME issuer, ASN1_INTEGER sno)
112	0	{
113	0	CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
114
115	0	if (rid->type == CMS_REK_ISSUER_SERIAL) {
116	0	if (issuer)
117	0	*issuer = rid->d.issuerAndSerialNumber->issuer;
118	0	if (sno)
119	0	*sno = rid->d.issuerAndSerialNumber->serialNumber;
120	0	if (keyid)
121	0	*keyid = NULL;
122	0	if (tm)
123	0	*tm = NULL;
124	0	if (other)
125	0	*other = NULL;
126	0	} else if (rid->type == CMS_REK_KEYIDENTIFIER) {
127	0	if (keyid)
128	0	*keyid = rid->d.rKeyId->subjectKeyIdentifier;
129	0	if (tm)
130	0	*tm = rid->d.rKeyId->date;
131	0	if (other)
132	0	*other = rid->d.rKeyId->other;
133	0	if (issuer)
134	0	*issuer = NULL;
135	0	if (sno)
136	0	*sno = NULL;
137	0	} else
138	0	return 0;
139	0	return 1;
140	0	}
141
142		int CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek,
143		X509 *cert)
144	0	{
145	0	CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
146
147	0	if (rid->type == CMS_REK_ISSUER_SERIAL)
148	0	return ossl_cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);
149	0	else if (rid->type == CMS_REK_KEYIDENTIFIER)
150	0	return ossl_cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier,
151	0	cert);
152	0	else
153	0	return -1;
154	0	}
155
156		int CMS_RecipientInfo_kari_set0_pkey_and_peer(CMS_RecipientInfo *ri,
157		EVP_PKEY pk, X509 peer)
158	0	{
159	0	EVP_PKEY_CTX *pctx;
160	0	CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;
161
162	0	EVP_PKEY_CTX_free(kari->pctx);
163	0	kari->pctx = NULL;
164	0	if (pk == NULL)
165	0	return 1;
166
167	0	pctx = EVP_PKEY_CTX_new_from_pkey(ossl_cms_ctx_get0_libctx(kari->cms_ctx),
168	0	pk,
169	0	ossl_cms_ctx_get0_propq(kari->cms_ctx));
170	0	if (pctx == NULL \|\| EVP_PKEY_derive_init(pctx) <= 0)
171	0	goto err;
172
173	0	if (peer != NULL) {
174	0	EVP_PKEY *pub_pkey = X509_get0_pubkey(peer);
175
176	0	if (EVP_PKEY_derive_set_peer(pctx, pub_pkey) <= 0)
177	0	goto err;
178	0	}
179
180	0	kari->pctx = pctx;
181	0	return 1;
182	0	err:
183	0	EVP_PKEY_CTX_free(pctx);
184	0	return 0;
185	0	}
186
187		int CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo ri, EVP_PKEY pk)
188	0	{
189	0	return CMS_RecipientInfo_kari_set0_pkey_and_peer(ri, pk, NULL);
190	0	}
191
192		EVP_CIPHER_CTX CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo ri)
193	0	{
194	0	if (ri->type == CMS_RECIPINFO_AGREE)
195	0	return ri->d.kari->ctx;
196	0	return NULL;
197	0	}
198
199		/*
200		* Derive KEK and decrypt/encrypt with it to produce either the original CEK
201		* or the encrypted CEK.
202		*/
203
204		static int cms_kek_cipher(unsigned char *pout, size_t poutlen,
205		const unsigned char *in, size_t inlen,
206		CMS_KeyAgreeRecipientInfo *kari, int enc)
207	0	{
208		/* Key encryption key */
209	0	unsigned char kek[EVP_MAX_KEY_LENGTH];
210	0	size_t keklen;
211	0	int rv = 0;
212	0	unsigned char *out = NULL;
213	0	size_t out_alloc_len = 0;
214	0	int outlen;
215	0	size_t outsize;
216
217	0	keklen = EVP_CIPHER_CTX_get_key_length(kari->ctx);
218	0	if (keklen > EVP_MAX_KEY_LENGTH \|\| inlen > INT_MAX)
219	0	return 0;
220		/* Derive KEK */
221	0	if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)
222	0	goto err;
223		/* Set KEK in context */
224	0	if (!EVP_CipherInit_ex(kari->ctx, NULL, NULL, kek, NULL, enc))
225	0	goto err;
226		/* obtain output length of ciphered key */
227	0	if (!EVP_CipherUpdate(kari->ctx, NULL, &outlen, in, (int)inlen))
228	0	goto err;
229		/*
230		* On its integrity-failure paths that primitive writes and cleanses up to
231		* inlen bytes of the output buffer. Size the buffer for that worst case so
232		* a failed unwrap cannot write past the allocation.
233		*/
234	0	outsize = (size_t)outlen < inlen ? inlen : (size_t)outlen;
235	0	out = OPENSSL_malloc(outsize);
236	0	if (out == NULL)
237	0	goto err;
238	0	out_alloc_len = (size_t)outlen;
239	0	if (!EVP_CipherUpdate(kari->ctx, out, &outlen, in, (int)inlen))
240	0	goto err;
241	0	*pout = out;
242	0	*poutlen = (size_t)outlen;
243	0	rv = 1;
244
245	0	err:
246	0	OPENSSL_cleanse(kek, keklen);
247	0	if (!rv)
248	0	OPENSSL_clear_free(out, out_alloc_len);
249	0	EVP_CIPHER_CTX_reset(kari->ctx);
250		/* FIXME: WHY IS kari->pctx freed here? /RL */
251	0	EVP_PKEY_CTX_free(kari->pctx);
252	0	kari->pctx = NULL;
253	0	return rv;
254	0	}
255
256		int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms,
257		CMS_RecipientInfo *ri,
258		CMS_RecipientEncryptedKey *rek)
259	0	{
260	0	int rv = 0;
261	0	unsigned char enckey = NULL, cek = NULL;
262	0	size_t enckeylen;
263	0	size_t ceklen;
264	0	CMS_EncryptedContentInfo *ec;
265
266	0	enckeylen = rek->encryptedKey->length;
267	0	enckey = rek->encryptedKey->data;
268		/* Setup all parameters to derive KEK */
269	0	if (!ossl_cms_env_asn1_ctrl(ri, 1))
270	0	goto err;
271		/* Attempt to decrypt CEK */
272	0	if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))
273	0	goto err;
274	0	ec = ossl_cms_get0_env_enc_content(cms);
275	0	OPENSSL_clear_free(ec->key, ec->keylen);
276	0	ec->key = cek;
277	0	ec->keylen = ceklen;
278	0	cek = NULL;
279	0	rv = 1;
280	0	err:
281	0	OPENSSL_free(cek);
282	0	return rv;
283	0	}
284
285		/* Create ephemeral key and initialise context based on it */
286		static int cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari,
287		EVP_PKEY *pk)
288	0	{
289	0	EVP_PKEY_CTX *pctx = NULL;
290	0	EVP_PKEY *ekey = NULL;
291	0	int rv = 0;
292	0	const CMS_CTX *ctx = kari->cms_ctx;
293	0	OSSL_LIB_CTX *libctx = ossl_cms_ctx_get0_libctx(ctx);
294	0	const char *propq = ossl_cms_ctx_get0_propq(ctx);
295
296	0	pctx = EVP_PKEY_CTX_new_from_pkey(libctx, pk, propq);
297	0	if (pctx == NULL)
298	0	goto err;
299	0	if (EVP_PKEY_keygen_init(pctx) <= 0)
300	0	goto err;
301	0	if (EVP_PKEY_keygen(pctx, &ekey) <= 0)
302	0	goto err;
303	0	EVP_PKEY_CTX_free(pctx);
304	0	pctx = EVP_PKEY_CTX_new_from_pkey(libctx, ekey, propq);
305	0	if (pctx == NULL)
306	0	goto err;
307	0	if (EVP_PKEY_derive_init(pctx) <= 0)
308	0	goto err;
309	0	kari->pctx = pctx;
310	0	rv = 1;
311	0	err:
312	0	if (!rv)
313	0	EVP_PKEY_CTX_free(pctx);
314	0	EVP_PKEY_free(ekey);
315	0	return rv;
316	0	}
317
318		/* Set originator private key and initialise context based on it */
319		static int cms_kari_set_originator_private_key(CMS_KeyAgreeRecipientInfo *kari,
320		EVP_PKEY *originatorPrivKey)
321	0	{
322	0	EVP_PKEY_CTX *pctx = NULL;
323	0	int rv = 0;
324	0	const CMS_CTX *ctx = kari->cms_ctx;
325
326	0	pctx = EVP_PKEY_CTX_new_from_pkey(ossl_cms_ctx_get0_libctx(ctx),
327	0	originatorPrivKey,
328	0	ossl_cms_ctx_get0_propq(ctx));
329	0	if (pctx == NULL)
330	0	goto err;
331	0	if (EVP_PKEY_derive_init(pctx) <= 0)
332	0	goto err;
333
334	0	kari->pctx = pctx;
335	0	rv = 1;
336	0	err:
337	0	if (rv == 0)
338	0	EVP_PKEY_CTX_free(pctx);
339	0	return rv;
340	0	}
341
342		/* Initialise a kari based on passed certificate and key */
343
344		int ossl_cms_RecipientInfo_kari_init(CMS_RecipientInfo ri, X509 recip,
345		EVP_PKEY recipPubKey, X509 originator,
346		EVP_PKEY *originatorPrivKey,
347		unsigned int flags, const CMS_CTX *ctx)
348	0	{
349	0	CMS_KeyAgreeRecipientInfo *kari;
350	0	CMS_RecipientEncryptedKey *rek = NULL;
351
352	0	ri->d.kari = M_ASN1_new_of(CMS_KeyAgreeRecipientInfo);
353	0	if (ri->d.kari == NULL)
354	0	return 0;
355	0	ri->encoded_type = ri->type = CMS_RECIPINFO_AGREE;
356
357	0	kari = ri->d.kari;
358	0	kari->version = 3;
359	0	kari->cms_ctx = ctx;
360
361	0	rek = M_ASN1_new_of(CMS_RecipientEncryptedKey);
362	0	if (rek == NULL)
363	0	return 0;
364
365	0	if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {
366	0	M_ASN1_free_of(rek, CMS_RecipientEncryptedKey);
367	0	return 0;
368	0	}
369
370	0	if (flags & CMS_USE_KEYID) {
371	0	rek->rid->type = CMS_REK_KEYIDENTIFIER;
372	0	rek->rid->d.rKeyId = M_ASN1_new_of(CMS_RecipientKeyIdentifier);
373	0	if (rek->rid->d.rKeyId == NULL)
374	0	return 0;
375	0	if (!ossl_cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))
376	0	return 0;
377	0	} else {
378	0	rek->rid->type = CMS_REK_ISSUER_SERIAL;
379	0	if (!ossl_cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))
380	0	return 0;
381	0	}
382
383	0	if (originatorPrivKey == NULL && originator == NULL) {
384		/* Create ephemeral key */
385	0	if (!cms_kari_create_ephemeral_key(kari, recipPubKey))
386	0	return 0;
387	0	} else {
388		/* Use originator key */
389	0	CMS_OriginatorIdentifierOrKey *oik = ri->d.kari->originator;
390
391	0	if (originatorPrivKey == NULL \|\| originator == NULL)
392	0	return 0;
393
394	0	if (flags & CMS_USE_ORIGINATOR_KEYID) {
395	0	oik->type = CMS_OIK_KEYIDENTIFIER;
396	0	oik->d.subjectKeyIdentifier = ASN1_OCTET_STRING_new();
397	0	if (oik->d.subjectKeyIdentifier == NULL)
398	0	return 0;
399	0	if (!ossl_cms_set1_keyid(&oik->d.subjectKeyIdentifier, originator))
400	0	return 0;
401	0	} else {
402	0	oik->type = CMS_REK_ISSUER_SERIAL;
403	0	if (!ossl_cms_set1_ias(&oik->d.issuerAndSerialNumber, originator))
404	0	return 0;
405	0	}
406
407	0	if (!cms_kari_set_originator_private_key(kari, originatorPrivKey))
408	0	return 0;
409	0	}
410
411	0	if (!EVP_PKEY_up_ref(recipPubKey))
412	0	return 0;
413
414	0	rek->pkey = recipPubKey;
415	0	return 1;
416	0	}
417
418		/* Encrypt content key in key agreement recipient info */
419
420		int ossl_cms_RecipientInfo_kari_encrypt(const CMS_ContentInfo *cms,
421		CMS_RecipientInfo *ri)
422	0	{
423	0	CMS_KeyAgreeRecipientInfo *kari;
424	0	CMS_EncryptedContentInfo *ec;
425	0	CMS_RecipientEncryptedKey *rek;
426	0	STACK_OF(CMS_RecipientEncryptedKey) *reks;
427	0	int i;
428
429	0	if (ri->type != CMS_RECIPINFO_AGREE) {
430	0	ERR_raise(ERR_LIB_CMS, CMS_R_NOT_KEY_AGREEMENT);
431	0	return 0;
432	0	}
433	0	kari = ri->d.kari;
434	0	reks = kari->recipientEncryptedKeys;
435	0	ec = ossl_cms_get0_env_enc_content(cms);
436		/* Initialise wrap algorithm parameters */
437	0	if (!ossl_cms_RecipientInfo_wrap_init(ri, ec->cipher))
438	0	return 0;
439		/*
440		* If no originator key set up initialise for ephemeral key the public key
441		* ASN1 structure will set the actual public key value.
442		*/
443	0	if (kari->originator->type == -1) {
444	0	CMS_OriginatorIdentifierOrKey *oik = kari->originator;
445	0	oik->type = CMS_OIK_PUBKEY;
446	0	oik->d.originatorKey = M_ASN1_new_of(CMS_OriginatorPublicKey);
447	0	if (!oik->d.originatorKey)
448	0	return 0;
449	0	} else {
450		/*
451		* Currently it is not possible to get public key as it is not stored
452		* during kari initialization.
453		*/
454	0	ERR_raise(ERR_LIB_CMS, CMS_R_ERROR_UNSUPPORTED_STATIC_KEY_AGREEMENT);
455	0	return 0;
456	0	}
457		/* Initialise KDF algorithm */
458	0	if (!ossl_cms_env_asn1_ctrl(ri, 0))
459	0	return 0;
460		/* For each rek, derive KEK, encrypt CEK */
461	0	for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {
462	0	unsigned char *enckey;
463	0	size_t enckeylen;
464	0	rek = sk_CMS_RecipientEncryptedKey_value(reks, i);
465	0	if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)
466	0	return 0;
467	0	if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,
468	0	kari, 1))
469	0	return 0;
470	0	ASN1_STRING_set0(rek->encryptedKey, enckey, (int)enckeylen);
471	0	}
472
473	0	return 1;
474	0	}