/src/openssl36/crypto/cms/cms_pwri.c

Source
/*
 * Copyright 2009-2025 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 "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/rand.h>
#include <openssl/aes.h>
#include "internal/sizes.h"
#include "crypto/asn1.h"
#include "cms_local.h"

int CMS_RecipientInfo_set0_password(CMS_RecipientInfo *ri,
                                    unsigned char *pass, ossl_ssize_t passlen)
{
    CMS_PasswordRecipientInfo *pwri;
    if (ri->type != CMS_RECIPINFO_PASS) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_PWRI);
        return 0;
    }

    pwri = ri->d.pwri;
    pwri->pass = pass;
    if (pass && passlen < 0)
        passlen = strlen((char *)pass);
    pwri->passlen = passlen;
    return 1;
}

CMS_RecipientInfo *CMS_add0_recipient_password(CMS_ContentInfo *cms,
                                               int iter, int wrap_nid,
                                               int pbe_nid,
                                               unsigned char *pass,
                                               ossl_ssize_t passlen,
                                               const EVP_CIPHER *kekciph)
{
    STACK_OF(CMS_RecipientInfo) *ris;
    CMS_RecipientInfo *ri = NULL;
    CMS_EncryptedContentInfo *ec;
    CMS_PasswordRecipientInfo *pwri;
    EVP_CIPHER_CTX *ctx = NULL;
    X509_ALGOR *encalg = NULL;
    unsigned char iv[EVP_MAX_IV_LENGTH];
    int ivlen;
    const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);

    ec = ossl_cms_get0_env_enc_content(cms);
    if (ec == NULL)
        return NULL;
    ris = CMS_get0_RecipientInfos(cms);
    if (ris == NULL)
        return NULL;

    if (wrap_nid <= 0)
        wrap_nid = NID_id_alg_PWRI_KEK;

    /* Get from enveloped data */
    if (kekciph == NULL)
        kekciph = ec->cipher;

    if (kekciph == NULL) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NO_CIPHER);
        return NULL;
    }
    if ((EVP_CIPHER_get_flags(kekciph) & EVP_CIPH_FLAG_AEAD_CIPHER) != 0) {
        ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEK_ALGORITHM);
        return NULL;
    }
    if (wrap_nid != NID_id_alg_PWRI_KEK) {
        ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
        return NULL;
    }

    /* Setup algorithm identifier for cipher */
    encalg = X509_ALGOR_new();
    if (encalg == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
        goto err;
    }
    ctx = EVP_CIPHER_CTX_new();
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
        goto err;
    }

    if (EVP_EncryptInit_ex(ctx, kekciph, NULL, NULL, NULL) <= 0) {
        ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
        goto err;
    }

    ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
    if (ivlen < 0) {
        ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
        goto err;
    }

    if (ivlen > 0) {
        if (RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), iv, ivlen, 0) <= 0)
            goto err;
        if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) <= 0) {
            ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
            goto err;
        }
        encalg->parameter = ASN1_TYPE_new();
        if (!encalg->parameter) {
            ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
            goto err;
        }
        if (EVP_CIPHER_param_to_asn1(ctx, encalg->parameter) <= 0) {
            ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
            goto err;
        }
    }

    encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_get_type(ctx));

    EVP_CIPHER_CTX_free(ctx);
    ctx = NULL;

    /* Initialize recipient info */
    ri = M_ASN1_new_of(CMS_RecipientInfo);
    if (ri == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
        goto err;
    }

    ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
    if (ri->d.pwri == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
        goto err;
    }
    ri->encoded_type = ri->type = CMS_RECIPINFO_PASS;

    pwri = ri->d.pwri;
    pwri->cms_ctx = cms_ctx;
    /* Since this is overwritten, free up empty structure already there */
    X509_ALGOR_free(pwri->keyEncryptionAlgorithm);
    pwri->keyEncryptionAlgorithm = X509_ALGOR_new();
    if (pwri->keyEncryptionAlgorithm == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
        goto err;
    }
    pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
    pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
    if (pwri->keyEncryptionAlgorithm->parameter == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
        goto err;
    }

    if (!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),
                        &pwri->keyEncryptionAlgorithm->parameter->
                        value.sequence)) {
        ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
        goto err;
    }
    pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;

    X509_ALGOR_free(encalg);
    encalg = NULL;

    /* Setup PBE algorithm */

    pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set_ex(iter, NULL, 0, -1, -1,
                                                       cms_ctx->libctx);

    if (pwri->keyDerivationAlgorithm == NULL)
        goto err;

    CMS_RecipientInfo_set0_password(ri, pass, passlen);
    pwri->version = 0;

    if (!sk_CMS_RecipientInfo_push(ris, ri)) {
        ERR_raise(ERR_LIB_CMS, ERR_R_CRYPTO_LIB);
        goto err;
    }

    return ri;

 err:
    EVP_CIPHER_CTX_free(ctx);
    if (ri)
        M_ASN1_free_of(ri, CMS_RecipientInfo);
    X509_ALGOR_free(encalg);
    return NULL;

}

/*
 * This is an implementation of the key wrapping mechanism in RFC3211, at
 * some point this should go into EVP.
 */

static int kek_unwrap_key(unsigned char *out, size_t *outlen,
                          const unsigned char *in, size_t inlen,
                          EVP_CIPHER_CTX *ctx)
{
    int blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
    unsigned char *tmp;
    int outl, rv = 0;

    if (blocklen <= 0)
        return 0;

    if (inlen < 2 * (size_t)blocklen) {
        /* too small */
        return 0;
    }
    if (inlen > INT_MAX || inlen % blocklen) {
        /* Invalid size */
        return 0;
    }
    if ((tmp = OPENSSL_malloc(inlen)) == NULL)
        return 0;
    /* setup IV by decrypting last two blocks */
    if (!EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,
                           in + inlen - 2 * blocklen, blocklen * 2)
        /*
         * Do a decrypt of last decrypted block to set IV to correct value
         * output it to start of buffer so we don't corrupt decrypted block
         * this works because buffer is at least two block lengths long.
         */
        || !EVP_DecryptUpdate(ctx, tmp, &outl,
                              tmp + inlen - blocklen, blocklen)
        /* Can now decrypt first n - 1 blocks */
        || !EVP_DecryptUpdate(ctx, tmp, &outl, in, (int)(inlen - blocklen))

        /* Reset IV to original value */
        || !EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL)
        /* Decrypt again */
        || !EVP_DecryptUpdate(ctx, tmp, &outl, tmp, (int)inlen))
        goto err;
    /* Check check bytes */
    if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff) {
        /* Check byte failure */
        goto err;
    }
    if (inlen < 4 + (size_t)tmp[0]) {
        /* Invalid length value */
        goto err;
    }
    *outlen = (size_t)tmp[0];
    memcpy(out, tmp + 4, *outlen);
    rv = 1;
 err:
    OPENSSL_clear_free(tmp, inlen);
    return rv;

}

static int kek_wrap_key(unsigned char *out, size_t *outlen,
                        const unsigned char *in, size_t inlen,
                        EVP_CIPHER_CTX *ctx, const CMS_CTX *cms_ctx)
{
    size_t blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
    size_t olen;
    int dummy;

    if (blocklen == 0)
        return 0;

    /*
     * First decide length of output buffer: need header and round up to
     * multiple of block length.
     */
    olen = (inlen + 4 + blocklen - 1) / blocklen;
    olen *= blocklen;
    if (olen < 2 * blocklen) {
        /* Key too small */
        return 0;
    }
    if (inlen > 0xFF) {
        /* Key too large */
        return 0;
    }
    if (out) {
        /* Set header */
        out[0] = (unsigned char)inlen;
        out[1] = in[0] ^ 0xFF;
        out[2] = in[1] ^ 0xFF;
        out[3] = in[2] ^ 0xFF;
        memcpy(out + 4, in, inlen);
        /* Add random padding to end */
        if (olen > inlen + 4
            && RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), out + 4 + inlen,
                             olen - 4 - inlen, 0) <= 0)
            return 0;
        /* Encrypt twice */
        if (!EVP_EncryptUpdate(ctx, out, &dummy, out, (int)olen)
            || !EVP_EncryptUpdate(ctx, out, &dummy, out, (int)olen))
            return 0;
    }

    *outlen = olen;

    return 1;
}

/* Encrypt/Decrypt content key in PWRI recipient info */

int ossl_cms_RecipientInfo_pwri_crypt(const CMS_ContentInfo *cms,
                                      CMS_RecipientInfo *ri, int en_de)
{
    CMS_EncryptedContentInfo *ec;
    CMS_PasswordRecipientInfo *pwri;
    int r = 0;
    X509_ALGOR *algtmp, *kekalg = NULL;
    EVP_CIPHER_CTX *kekctx = NULL;
    char name[OSSL_MAX_NAME_SIZE];
    EVP_CIPHER *kekcipher;
    unsigned char *key = NULL;
    size_t keylen;
    const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);

    ec = ossl_cms_get0_env_enc_content(cms);

    pwri = ri->d.pwri;

    if (pwri->pass == NULL) {
        ERR_raise(ERR_LIB_CMS, CMS_R_NO_PASSWORD);
        return 0;
    }
    algtmp = pwri->keyEncryptionAlgorithm;

    if (!algtmp || OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK) {
        ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
        return 0;
    }

    kekalg = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),
                                       algtmp->parameter);

    if (kekalg == NULL) {
        ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);
        return 0;
    }

    OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0);
    kekcipher = EVP_CIPHER_fetch(ossl_cms_ctx_get0_libctx(cms_ctx), name,
                                 ossl_cms_ctx_get0_propq(cms_ctx));

    if (kekcipher == NULL) {
        ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);
        goto err;
    }

    kekctx = EVP_CIPHER_CTX_new();
    if (kekctx == NULL) {
        ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
        goto err;
    }
    /* Fixup cipher based on AlgorithmIdentifier to set IV etc */
    if (!EVP_CipherInit_ex(kekctx, kekcipher, NULL, NULL, NULL, en_de))
        goto err;
    EVP_CIPHER_CTX_set_padding(kekctx, 0);
    if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) {
        ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
        goto err;
    }

    algtmp = pwri->keyDerivationAlgorithm;

    /* Finish password based key derivation to setup key in "ctx" */

    if (!EVP_PBE_CipherInit_ex(algtmp->algorithm,
                               (char *)pwri->pass, (int)pwri->passlen,
                               algtmp->parameter, kekctx, en_de,
                               cms_ctx->libctx, cms_ctx->propq)) {
        ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
        goto err;
    }

    /* Finally wrap/unwrap the key */

    if (en_de) {

        if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
            goto err;

        key = OPENSSL_malloc(keylen);

        if (key == NULL)
            goto err;

        if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
            goto err;
        pwri->encryptedKey->data = key;
        pwri->encryptedKey->length = (int)keylen;
    } else {
        key = OPENSSL_malloc(pwri->encryptedKey->length);
        if (key == NULL)
            goto err;
        if (!kek_unwrap_key(key, &keylen,
                            pwri->encryptedKey->data,
                            pwri->encryptedKey->length, kekctx)) {
            ERR_raise(ERR_LIB_CMS, CMS_R_UNWRAP_FAILURE);
            goto err;
        }

        OPENSSL_clear_free(ec->key, ec->keylen);
        ec->key = key;
        ec->keylen = keylen;

    }

    r = 1;

 err:
    EVP_CIPHER_free(kekcipher);
    EVP_CIPHER_CTX_free(kekctx);

    if (!r)
        OPENSSL_free(key);
    X509_ALGOR_free(kekalg);

    return r;

}

Coverage Report

Created: 2025-12-04 06:33

Line	Count	Source
1		/*
2		* Copyright 2009-2025 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 "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/rand.h>
17		#include <openssl/aes.h>
18		#include "internal/sizes.h"
19		#include "crypto/asn1.h"
20		#include "cms_local.h"
21
22		int CMS_RecipientInfo_set0_password(CMS_RecipientInfo *ri,
23		unsigned char *pass, ossl_ssize_t passlen)
24	0	{
25	0	CMS_PasswordRecipientInfo *pwri;
26	0	if (ri->type != CMS_RECIPINFO_PASS) {
27	0	ERR_raise(ERR_LIB_CMS, CMS_R_NOT_PWRI);
28	0	return 0;
29	0	}
30
31	0	pwri = ri->d.pwri;
32	0	pwri->pass = pass;
33	0	if (pass && passlen < 0)
34	0	passlen = strlen((char *)pass);
35	0	pwri->passlen = passlen;
36	0	return 1;
37	0	}
38
39		CMS_RecipientInfo CMS_add0_recipient_password(CMS_ContentInfo cms,
40		int iter, int wrap_nid,
41		int pbe_nid,
42		unsigned char *pass,
43		ossl_ssize_t passlen,
44		const EVP_CIPHER *kekciph)
45	0	{
46	0	STACK_OF(CMS_RecipientInfo) *ris;
47	0	CMS_RecipientInfo *ri = NULL;
48	0	CMS_EncryptedContentInfo *ec;
49	0	CMS_PasswordRecipientInfo *pwri;
50	0	EVP_CIPHER_CTX *ctx = NULL;
51	0	X509_ALGOR *encalg = NULL;
52	0	unsigned char iv[EVP_MAX_IV_LENGTH];
53	0	int ivlen;
54	0	const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);
55
56	0	ec = ossl_cms_get0_env_enc_content(cms);
57	0	if (ec == NULL)
58	0	return NULL;
59	0	ris = CMS_get0_RecipientInfos(cms);
60	0	if (ris == NULL)
61	0	return NULL;
62
63	0	if (wrap_nid <= 0)
64	0	wrap_nid = NID_id_alg_PWRI_KEK;
65
66		/* Get from enveloped data */
67	0	if (kekciph == NULL)
68	0	kekciph = ec->cipher;
69
70	0	if (kekciph == NULL) {
71	0	ERR_raise(ERR_LIB_CMS, CMS_R_NO_CIPHER);
72	0	return NULL;
73	0	}
74	0	if ((EVP_CIPHER_get_flags(kekciph) & EVP_CIPH_FLAG_AEAD_CIPHER) != 0) {
75	0	ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEK_ALGORITHM);
76	0	return NULL;
77	0	}
78	0	if (wrap_nid != NID_id_alg_PWRI_KEK) {
79	0	ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
80	0	return NULL;
81	0	}
82
83		/* Setup algorithm identifier for cipher */
84	0	encalg = X509_ALGOR_new();
85	0	if (encalg == NULL) {
86	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
87	0	goto err;
88	0	}
89	0	ctx = EVP_CIPHER_CTX_new();
90	0	if (ctx == NULL) {
91	0	ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
92	0	goto err;
93	0	}
94
95	0	if (EVP_EncryptInit_ex(ctx, kekciph, NULL, NULL, NULL) <= 0) {
96	0	ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
97	0	goto err;
98	0	}
99
100	0	ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
101	0	if (ivlen < 0) {
102	0	ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
103	0	goto err;
104	0	}
105
106	0	if (ivlen > 0) {
107	0	if (RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), iv, ivlen, 0) <= 0)
108	0	goto err;
109	0	if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) <= 0) {
110	0	ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
111	0	goto err;
112	0	}
113	0	encalg->parameter = ASN1_TYPE_new();
114	0	if (!encalg->parameter) {
115	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
116	0	goto err;
117	0	}
118	0	if (EVP_CIPHER_param_to_asn1(ctx, encalg->parameter) <= 0) {
119	0	ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
120	0	goto err;
121	0	}
122	0	}
123
124	0	encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_get_type(ctx));
125
126	0	EVP_CIPHER_CTX_free(ctx);
127	0	ctx = NULL;
128
129		/* Initialize recipient info */
130	0	ri = M_ASN1_new_of(CMS_RecipientInfo);
131	0	if (ri == NULL) {
132	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
133	0	goto err;
134	0	}
135
136	0	ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
137	0	if (ri->d.pwri == NULL) {
138	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
139	0	goto err;
140	0	}
141	0	ri->encoded_type = ri->type = CMS_RECIPINFO_PASS;
142
143	0	pwri = ri->d.pwri;
144	0	pwri->cms_ctx = cms_ctx;
145		/* Since this is overwritten, free up empty structure already there */
146	0	X509_ALGOR_free(pwri->keyEncryptionAlgorithm);
147	0	pwri->keyEncryptionAlgorithm = X509_ALGOR_new();
148	0	if (pwri->keyEncryptionAlgorithm == NULL) {
149	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
150	0	goto err;
151	0	}
152	0	pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
153	0	pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
154	0	if (pwri->keyEncryptionAlgorithm->parameter == NULL) {
155	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
156	0	goto err;
157	0	}
158
159	0	if (!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),
160	0	&pwri->keyEncryptionAlgorithm->parameter->
161	0	value.sequence)) {
162	0	ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);
163	0	goto err;
164	0	}
165	0	pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;
166
167	0	X509_ALGOR_free(encalg);
168	0	encalg = NULL;
169
170		/* Setup PBE algorithm */
171
172	0	pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set_ex(iter, NULL, 0, -1, -1,
173	0	cms_ctx->libctx);
174
175	0	if (pwri->keyDerivationAlgorithm == NULL)
176	0	goto err;
177
178	0	CMS_RecipientInfo_set0_password(ri, pass, passlen);
179	0	pwri->version = 0;
180
181	0	if (!sk_CMS_RecipientInfo_push(ris, ri)) {
182	0	ERR_raise(ERR_LIB_CMS, ERR_R_CRYPTO_LIB);
183	0	goto err;
184	0	}
185
186	0	return ri;
187
188	0	err:
189	0	EVP_CIPHER_CTX_free(ctx);
190	0	if (ri)
191	0	M_ASN1_free_of(ri, CMS_RecipientInfo);
192	0	X509_ALGOR_free(encalg);
193	0	return NULL;
194
195	0	}
196
197		/*
198		* This is an implementation of the key wrapping mechanism in RFC3211, at
199		* some point this should go into EVP.
200		*/
201
202		static int kek_unwrap_key(unsigned char out, size_t outlen,
203		const unsigned char *in, size_t inlen,
204		EVP_CIPHER_CTX *ctx)
205	0	{
206	0	int blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
207	0	unsigned char *tmp;
208	0	int outl, rv = 0;
209
210	0	if (blocklen <= 0)
211	0	return 0;
212
213	0	if (inlen < 2 * (size_t)blocklen) {
214		/* too small */
215	0	return 0;
216	0	}
217	0	if (inlen > INT_MAX \|\| inlen % blocklen) {
218		/* Invalid size */
219	0	return 0;
220	0	}
221	0	if ((tmp = OPENSSL_malloc(inlen)) == NULL)
222	0	return 0;
223		/* setup IV by decrypting last two blocks */
224	0	if (!EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,
225	0	in + inlen - 2 * blocklen, blocklen * 2)
226		/*
227		* Do a decrypt of last decrypted block to set IV to correct value
228		* output it to start of buffer so we don't corrupt decrypted block
229		* this works because buffer is at least two block lengths long.
230		*/
231	0	\|\| !EVP_DecryptUpdate(ctx, tmp, &outl,
232	0	tmp + inlen - blocklen, blocklen)
233		/* Can now decrypt first n - 1 blocks */
234	0	\|\| !EVP_DecryptUpdate(ctx, tmp, &outl, in, (int)(inlen - blocklen))
235
236		/* Reset IV to original value */
237	0	\|\| !EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL)
238		/* Decrypt again */
239	0	\|\| !EVP_DecryptUpdate(ctx, tmp, &outl, tmp, (int)inlen))
240	0	goto err;
241		/* Check check bytes */
242	0	if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff) {
243		/* Check byte failure */
244	0	goto err;
245	0	}
246	0	if (inlen < 4 + (size_t)tmp[0]) {
247		/* Invalid length value */
248	0	goto err;
249	0	}
250	0	*outlen = (size_t)tmp[0];
251	0	memcpy(out, tmp + 4, *outlen);
252	0	rv = 1;
253	0	err:
254	0	OPENSSL_clear_free(tmp, inlen);
255	0	return rv;
256
257	0	}
258
259		static int kek_wrap_key(unsigned char out, size_t outlen,
260		const unsigned char *in, size_t inlen,
261		EVP_CIPHER_CTX ctx, const CMS_CTX cms_ctx)
262	0	{
263	0	size_t blocklen = EVP_CIPHER_CTX_get_block_size(ctx);
264	0	size_t olen;
265	0	int dummy;
266
267	0	if (blocklen == 0)
268	0	return 0;
269
270		/*
271		* First decide length of output buffer: need header and round up to
272		* multiple of block length.
273		*/
274	0	olen = (inlen + 4 + blocklen - 1) / blocklen;
275	0	olen *= blocklen;
276	0	if (olen < 2 * blocklen) {
277		/* Key too small */
278	0	return 0;
279	0	}
280	0	if (inlen > 0xFF) {
281		/* Key too large */
282	0	return 0;
283	0	}
284	0	if (out) {
285		/* Set header */
286	0	out[0] = (unsigned char)inlen;
287	0	out[1] = in[0] ^ 0xFF;
288	0	out[2] = in[1] ^ 0xFF;
289	0	out[3] = in[2] ^ 0xFF;
290	0	memcpy(out + 4, in, inlen);
291		/* Add random padding to end */
292	0	if (olen > inlen + 4
293	0	&& RAND_bytes_ex(ossl_cms_ctx_get0_libctx(cms_ctx), out + 4 + inlen,
294	0	olen - 4 - inlen, 0) <= 0)
295	0	return 0;
296		/* Encrypt twice */
297	0	if (!EVP_EncryptUpdate(ctx, out, &dummy, out, (int)olen)
298	0	\|\| !EVP_EncryptUpdate(ctx, out, &dummy, out, (int)olen))
299	0	return 0;
300	0	}
301
302	0	*outlen = olen;
303
304	0	return 1;
305	0	}
306
307		/* Encrypt/Decrypt content key in PWRI recipient info */
308
309		int ossl_cms_RecipientInfo_pwri_crypt(const CMS_ContentInfo *cms,
310		CMS_RecipientInfo *ri, int en_de)
311	0	{
312	0	CMS_EncryptedContentInfo *ec;
313	0	CMS_PasswordRecipientInfo *pwri;
314	0	int r = 0;
315	0	X509_ALGOR algtmp, kekalg = NULL;
316	0	EVP_CIPHER_CTX *kekctx = NULL;
317	0	char name[OSSL_MAX_NAME_SIZE];
318	0	EVP_CIPHER *kekcipher;
319	0	unsigned char *key = NULL;
320	0	size_t keylen;
321	0	const CMS_CTX *cms_ctx = ossl_cms_get0_cmsctx(cms);
322
323	0	ec = ossl_cms_get0_env_enc_content(cms);
324
325	0	pwri = ri->d.pwri;
326
327	0	if (pwri->pass == NULL) {
328	0	ERR_raise(ERR_LIB_CMS, CMS_R_NO_PASSWORD);
329	0	return 0;
330	0	}
331	0	algtmp = pwri->keyEncryptionAlgorithm;
332
333	0	if (!algtmp \|\| OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK) {
334	0	ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
335	0	return 0;
336	0	}
337
338	0	kekalg = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),
339	0	algtmp->parameter);
340
341	0	if (kekalg == NULL) {
342	0	ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);
343	0	return 0;
344	0	}
345
346	0	OBJ_obj2txt(name, sizeof(name), kekalg->algorithm, 0);
347	0	kekcipher = EVP_CIPHER_fetch(ossl_cms_ctx_get0_libctx(cms_ctx), name,
348	0	ossl_cms_ctx_get0_propq(cms_ctx));
349
350	0	if (kekcipher == NULL) {
351	0	ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);
352	0	goto err;
353	0	}
354
355	0	kekctx = EVP_CIPHER_CTX_new();
356	0	if (kekctx == NULL) {
357	0	ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
358	0	goto err;
359	0	}
360		/* Fixup cipher based on AlgorithmIdentifier to set IV etc */
361	0	if (!EVP_CipherInit_ex(kekctx, kekcipher, NULL, NULL, NULL, en_de))
362	0	goto err;
363	0	EVP_CIPHER_CTX_set_padding(kekctx, 0);
364	0	if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) {
365	0	ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
366	0	goto err;
367	0	}
368
369	0	algtmp = pwri->keyDerivationAlgorithm;
370
371		/* Finish password based key derivation to setup key in "ctx" */
372
373	0	if (!EVP_PBE_CipherInit_ex(algtmp->algorithm,
374	0	(char *)pwri->pass, (int)pwri->passlen,
375	0	algtmp->parameter, kekctx, en_de,
376	0	cms_ctx->libctx, cms_ctx->propq)) {
377	0	ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
378	0	goto err;
379	0	}
380
381		/* Finally wrap/unwrap the key */
382
383	0	if (en_de) {
384
385	0	if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
386	0	goto err;
387
388	0	key = OPENSSL_malloc(keylen);
389
390	0	if (key == NULL)
391	0	goto err;
392
393	0	if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, kekctx, cms_ctx))
394	0	goto err;
395	0	pwri->encryptedKey->data = key;
396	0	pwri->encryptedKey->length = (int)keylen;
397	0	} else {
398	0	key = OPENSSL_malloc(pwri->encryptedKey->length);
399	0	if (key == NULL)
400	0	goto err;
401	0	if (!kek_unwrap_key(key, &keylen,
402	0	pwri->encryptedKey->data,
403	0	pwri->encryptedKey->length, kekctx)) {
404	0	ERR_raise(ERR_LIB_CMS, CMS_R_UNWRAP_FAILURE);
405	0	goto err;
406	0	}
407
408	0	OPENSSL_clear_free(ec->key, ec->keylen);
409	0	ec->key = key;
410	0	ec->keylen = keylen;
411
412	0	}
413
414	0	r = 1;
415
416	0	err:
417	0	EVP_CIPHER_free(kekcipher);
418	0	EVP_CIPHER_CTX_free(kekctx);
419
420	0	if (!r)
421	0	OPENSSL_free(key);
422	0	X509_ALGOR_free(kekalg);
423
424	0	return r;
425
426	0	}