1/*
2 * Copyright 2008-2023 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 <openssl/asn1.h>
11#include <openssl/asn1t.h>
12#include <openssl/bio.h>
13#include <openssl/err.h>
14
15#include <stdio.h>
16
17/* Experimental NDEF ASN1 BIO support routines */
18
19/*
20 * The usage is quite simple, initialize an ASN1 structure, get a BIO from it
21 * then any data written through the BIO will end up translated to
22 * appropriate format on the fly. The data is streamed out and does *not*
23 * need to be all held in memory at once. When the BIO is flushed the output
24 * is finalized and any signatures etc written out. The BIO is a 'proper'
25 * BIO and can handle non blocking I/O correctly. The usage is simple. The
26 * implementation is *not*...
27 */
28
29/* BIO support data stored in the ASN1 BIO ex_arg */
30
31typedef struct ndef_aux_st {
32    /* ASN1 structure this BIO refers to */
33    ASN1_VALUE *val;
34    const ASN1_ITEM *it;
35    /* Top of the BIO chain */
36    BIO *ndef_bio;
37    /* Output BIO */
38    BIO *out;
39    /* Boundary where content is inserted */
40    unsigned char **boundary;
41    /* DER buffer start */
42    unsigned char *derbuf;
43} NDEF_SUPPORT;
44
45static int ndef_prefix(BIO *b, unsigned char **pbuf, int *plen, void *parg);
46static int ndef_prefix_free(BIO *b, unsigned char **pbuf, int *plen,
47                            void *parg);
48static int ndef_suffix(BIO *b, unsigned char **pbuf, int *plen, void *parg);
49static int ndef_suffix_free(BIO *b, unsigned char **pbuf, int *plen,
50                            void *parg);
51
52/*
53 * On success, the returned BIO owns the input BIO as part of its BIO chain.
54 * On failure, NULL is returned and the input BIO is owned by the caller.
55 *
56 * Unfortunately cannot constify this due to CMS_stream() and PKCS7_stream()
57 */
58BIO *BIO_new_NDEF(BIO *out, ASN1_VALUE *val, const ASN1_ITEM *it)
59{
60    NDEF_SUPPORT *ndef_aux = NULL;
61    BIO *asn_bio = NULL;
62    const ASN1_AUX *aux = it->funcs;
63    ASN1_STREAM_ARG sarg;
64    BIO *pop_bio = NULL;
65
66    if (!aux || !aux->asn1_cb) {
67        ERR_raise(ERR_LIB_ASN1, ASN1_R_STREAMING_NOT_SUPPORTED);
68        return NULL;
69    }
70    ndef_aux = OPENSSL_zalloc(sizeof(*ndef_aux));
71    asn_bio = BIO_new(BIO_f_asn1());
72    if (ndef_aux == NULL || asn_bio == NULL)
73        goto err;
74
75    /* ASN1 bio needs to be next to output BIO */
76    out = BIO_push(asn_bio, out);
77    if (out == NULL)
78        goto err;
79    pop_bio = asn_bio;
80
81    if (BIO_asn1_set_prefix(asn_bio, ndef_prefix, ndef_prefix_free) <= 0
82            || BIO_asn1_set_suffix(asn_bio, ndef_suffix, ndef_suffix_free) <= 0
83            || BIO_ctrl(asn_bio, BIO_C_SET_EX_ARG, 0, ndef_aux) <= 0)
84        goto err;
85
86    /*
87     * Now let the callback prepend any digest, cipher, etc., that the BIO's
88     * ASN1 structure needs.
89     */
90
91    sarg.out = out;
92    sarg.ndef_bio = NULL;
93    sarg.boundary = NULL;
94
95    /*
96     * The asn1_cb(), must not have mutated asn_bio on error, leaving it in the
97     * middle of some partially built, but not returned BIO chain.
98     */
99    if (aux->asn1_cb(ASN1_OP_STREAM_PRE, &val, it, &sarg) <= 0) {
100        /*
101         * ndef_aux is now owned by asn_bio so we must not free it in the err
102         * clean up block
103         */
104        ndef_aux = NULL;
105        goto err;
106    }
107
108    /*
109     * We must not fail now because the callback has prepended additional
110     * BIOs to the chain
111     */
112
113    ndef_aux->val = val;
114    ndef_aux->it = it;
115    ndef_aux->ndef_bio = sarg.ndef_bio;
116    ndef_aux->boundary = sarg.boundary;
117    ndef_aux->out = out;
118
119    return sarg.ndef_bio;
120
121 err:
122    /* BIO_pop() is NULL safe */
123    (void)BIO_pop(pop_bio);
124    BIO_free(asn_bio);
125    OPENSSL_free(ndef_aux);
126    return NULL;
127}
128
129static int ndef_prefix(BIO *b, unsigned char **pbuf, int *plen, void *parg)
130{
131    NDEF_SUPPORT *ndef_aux;
132    unsigned char *p;
133    int derlen;
134
135    if (parg == NULL)
136        return 0;
137
138    ndef_aux = *(NDEF_SUPPORT **)parg;
139
140    derlen = ASN1_item_ndef_i2d(ndef_aux->val, NULL, ndef_aux->it);
141    if (derlen < 0)
142        return 0;
143    if ((p = OPENSSL_malloc(derlen)) == NULL) {
144        ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
145        return 0;
146    }
147
148    ndef_aux->derbuf = p;
149    *pbuf = p;
150    ASN1_item_ndef_i2d(ndef_aux->val, &p, ndef_aux->it);
151
152    if (*ndef_aux->boundary == NULL)
153        return 0;
154
155    *plen = *ndef_aux->boundary - *pbuf;
156
157    return 1;
158}
159
160static int ndef_prefix_free(BIO *b, unsigned char **pbuf, int *plen,
161                            void *parg)
162{
163    NDEF_SUPPORT *ndef_aux;
164
165    if (parg == NULL)
166        return 0;
167
168    ndef_aux = *(NDEF_SUPPORT **)parg;
169
170    if (ndef_aux == NULL)
171        return 0;
172
173    OPENSSL_free(ndef_aux->derbuf);
174
175    ndef_aux->derbuf = NULL;
176    *pbuf = NULL;
177    *plen = 0;
178    return 1;
179}
180
181static int ndef_suffix_free(BIO *b, unsigned char **pbuf, int *plen,
182                            void *parg)
183{
184    NDEF_SUPPORT **pndef_aux = (NDEF_SUPPORT **)parg;
185    if (!ndef_prefix_free(b, pbuf, plen, parg))
186        return 0;
187    OPENSSL_free(*pndef_aux);
188    *pndef_aux = NULL;
189    return 1;
190}
191
192static int ndef_suffix(BIO *b, unsigned char **pbuf, int *plen, void *parg)
193{
194    NDEF_SUPPORT *ndef_aux;
195    unsigned char *p;
196    int derlen;
197    const ASN1_AUX *aux;
198    ASN1_STREAM_ARG sarg;
199
200    if (parg == NULL)
201        return 0;
202
203    ndef_aux = *(NDEF_SUPPORT **)parg;
204
205    aux = ndef_aux->it->funcs;
206
207    /* Finalize structures */
208    sarg.ndef_bio = ndef_aux->ndef_bio;
209    sarg.out = ndef_aux->out;
210    sarg.boundary = ndef_aux->boundary;
211    if (aux->asn1_cb(ASN1_OP_STREAM_POST,
212                     &ndef_aux->val, ndef_aux->it, &sarg) <= 0)
213        return 0;
214
215    derlen = ASN1_item_ndef_i2d(ndef_aux->val, NULL, ndef_aux->it);
216    if (derlen < 0)
217        return 0;
218    if ((p = OPENSSL_malloc(derlen)) == NULL) {
219        ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
220        return 0;
221    }
222
223    ndef_aux->derbuf = p;
224    *pbuf = p;
225    derlen = ASN1_item_ndef_i2d(ndef_aux->val, &p, ndef_aux->it);
226
227    if (*ndef_aux->boundary == NULL)
228        return 0;
229    *pbuf = *ndef_aux->boundary;
230    *plen = derlen - (*ndef_aux->boundary - ndef_aux->derbuf);
231
232    return 1;
233}
234