1/*
2 * Copyright 2020-2022 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/core_names.h>
11#include <openssl/bio.h>
12#include <openssl/params.h>
13#include <openssl/provider.h>
14#include <openssl/evperr.h>
15#include <openssl/ecerr.h>
16#include <openssl/pkcs12err.h>
17#include <openssl/x509err.h>
18#include <openssl/trace.h>
19#include "internal/bio.h"
20#include "internal/provider.h"
21#include "crypto/decoder.h"
22#include "encoder_local.h"
23#include "e_os.h"
24
25struct decoder_process_data_st {
26    OSSL_DECODER_CTX *ctx;
27
28    /* Current BIO */
29    BIO *bio;
30
31    /* Index of the current decoder instance to be processed */
32    size_t current_decoder_inst_index;
33    /* For tracing, count recursion level */
34    size_t recursion;
35
36    /*-
37     * Flags
38     */
39    unsigned int flag_next_level_called : 1;
40    unsigned int flag_construct_called : 1;
41    unsigned int flag_input_structure_checked : 1;
42};
43
44static int decoder_process(const OSSL_PARAM params[], void *arg);
45
46int OSSL_DECODER_from_bio(OSSL_DECODER_CTX *ctx, BIO *in)
47{
48    struct decoder_process_data_st data;
49    int ok = 0;
50    BIO *new_bio = NULL;
51    unsigned long lasterr;
52
53    if (in == NULL) {
54        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
55        return 0;
56    }
57
58    if (OSSL_DECODER_CTX_get_num_decoders(ctx) == 0) {
59        ERR_raise_data(ERR_LIB_OSSL_DECODER, OSSL_DECODER_R_DECODER_NOT_FOUND,
60                       "No decoders were found. For standard decoders you need "
61                       "at least one of the default or base providers "
62                       "available. Did you forget to load them?");
63        return 0;
64    }
65
66    lasterr = ERR_peek_last_error();
67
68    if (BIO_tell(in) < 0) {
69        new_bio = BIO_new(BIO_f_readbuffer());
70        if (new_bio == NULL)
71            return 0;
72        in = BIO_push(new_bio, in);
73    }
74    memset(&data, 0, sizeof(data));
75    data.ctx = ctx;
76    data.bio = in;
77
78    /* Enable passphrase caching */
79    (void)ossl_pw_enable_passphrase_caching(&ctx->pwdata);
80
81    ok = decoder_process(NULL, &data);
82
83    if (!data.flag_construct_called) {
84        const char *spaces
85            = ctx->start_input_type != NULL && ctx->input_structure != NULL
86            ? " " : "";
87        const char *input_type_label
88            = ctx->start_input_type != NULL ? "Input type: " : "";
89        const char *input_structure_label
90            = ctx->input_structure != NULL ? "Input structure: " : "";
91        const char *comma
92            = ctx->start_input_type != NULL && ctx->input_structure != NULL
93            ? ", " : "";
94        const char *input_type
95            = ctx->start_input_type != NULL ? ctx->start_input_type : "";
96        const char *input_structure
97            = ctx->input_structure != NULL ? ctx->input_structure : "";
98
99        if (ERR_peek_last_error() == lasterr || ERR_peek_error() == 0)
100            /* Prevent spurious decoding error but add at least something */
101            ERR_raise_data(ERR_LIB_OSSL_DECODER, ERR_R_UNSUPPORTED,
102                           "No supported data to decode. %s%s%s%s%s%s",
103                           spaces, input_type_label, input_type, comma,
104                           input_structure_label, input_structure);
105        ok = 0;
106    }
107
108    /* Clear any internally cached passphrase */
109    (void)ossl_pw_clear_passphrase_cache(&ctx->pwdata);
110
111    if (new_bio != NULL) {
112        BIO_pop(new_bio);
113        BIO_free(new_bio);
114    }
115    return ok;
116}
117
118#ifndef OPENSSL_NO_STDIO
119static BIO *bio_from_file(FILE *fp)
120{
121    BIO *b;
122
123    if ((b = BIO_new(BIO_s_file())) == NULL) {
124        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_BIO_LIB);
125        return NULL;
126    }
127    BIO_set_fp(b, fp, BIO_NOCLOSE);
128    return b;
129}
130
131int OSSL_DECODER_from_fp(OSSL_DECODER_CTX *ctx, FILE *fp)
132{
133    BIO *b = bio_from_file(fp);
134    int ret = 0;
135
136    if (b != NULL)
137        ret = OSSL_DECODER_from_bio(ctx, b);
138
139    BIO_free(b);
140    return ret;
141}
142#endif
143
144int OSSL_DECODER_from_data(OSSL_DECODER_CTX *ctx, const unsigned char **pdata,
145                           size_t *pdata_len)
146{
147    BIO *membio;
148    int ret = 0;
149
150    if (pdata == NULL || *pdata == NULL || pdata_len == NULL) {
151        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
152        return 0;
153    }
154
155    membio = BIO_new_mem_buf(*pdata, (int)*pdata_len);
156    if (OSSL_DECODER_from_bio(ctx, membio)) {
157        *pdata_len = (size_t)BIO_get_mem_data(membio, pdata);
158        ret = 1;
159    }
160    BIO_free(membio);
161
162    return ret;
163}
164
165int OSSL_DECODER_CTX_set_selection(OSSL_DECODER_CTX *ctx, int selection)
166{
167    if (!ossl_assert(ctx != NULL)) {
168        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
169        return 0;
170    }
171
172    /*
173     * 0 is a valid selection, and means that the caller leaves
174     * it to code to discover what the selection is.
175     */
176    ctx->selection = selection;
177    return 1;
178}
179
180int OSSL_DECODER_CTX_set_input_type(OSSL_DECODER_CTX *ctx,
181                                    const char *input_type)
182{
183    if (!ossl_assert(ctx != NULL)) {
184        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
185        return 0;
186    }
187
188    /*
189     * NULL is a valid starting input type, and means that the caller leaves
190     * it to code to discover what the starting input type is.
191     */
192    ctx->start_input_type = input_type;
193    return 1;
194}
195
196int OSSL_DECODER_CTX_set_input_structure(OSSL_DECODER_CTX *ctx,
197                                         const char *input_structure)
198{
199    if (!ossl_assert(ctx != NULL)) {
200        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
201        return 0;
202    }
203
204    /*
205     * NULL is a valid starting input structure, and means that the caller
206     * leaves it to code to discover what the starting input structure is.
207     */
208    ctx->input_structure = input_structure;
209    return 1;
210}
211
212OSSL_DECODER_INSTANCE *ossl_decoder_instance_new(OSSL_DECODER *decoder,
213                                                 void *decoderctx)
214{
215    OSSL_DECODER_INSTANCE *decoder_inst = NULL;
216    const OSSL_PROVIDER *prov;
217    OSSL_LIB_CTX *libctx;
218    const OSSL_PROPERTY_LIST *props;
219    const OSSL_PROPERTY_DEFINITION *prop;
220
221    if (!ossl_assert(decoder != NULL)) {
222        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
223        return 0;
224    }
225
226    if ((decoder_inst = OPENSSL_zalloc(sizeof(*decoder_inst))) == NULL) {
227        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_MALLOC_FAILURE);
228        return 0;
229    }
230
231    prov = OSSL_DECODER_get0_provider(decoder);
232    libctx = ossl_provider_libctx(prov);
233    props = ossl_decoder_parsed_properties(decoder);
234    if (props == NULL) {
235        ERR_raise_data(ERR_LIB_OSSL_DECODER, ERR_R_INVALID_PROPERTY_DEFINITION,
236                       "there are no property definitions with decoder %s",
237                       OSSL_DECODER_get0_name(decoder));
238        goto err;
239    }
240
241    /* The "input" property is mandatory */
242    prop = ossl_property_find_property(props, libctx, "input");
243    decoder_inst->input_type = ossl_property_get_string_value(libctx, prop);
244    if (decoder_inst->input_type == NULL) {
245        ERR_raise_data(ERR_LIB_OSSL_DECODER, ERR_R_INVALID_PROPERTY_DEFINITION,
246                       "the mandatory 'input' property is missing "
247                       "for decoder %s (properties: %s)",
248                       OSSL_DECODER_get0_name(decoder),
249                       OSSL_DECODER_get0_properties(decoder));
250        goto err;
251    }
252
253    /* The "structure" property is optional */
254    prop = ossl_property_find_property(props, libctx, "structure");
255    if (prop != NULL) {
256        decoder_inst->input_structure
257            = ossl_property_get_string_value(libctx, prop);
258    }
259
260    if (!OSSL_DECODER_up_ref(decoder)) {
261        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_INTERNAL_ERROR);
262        goto err;
263    }
264    decoder_inst->decoder = decoder;
265    decoder_inst->decoderctx = decoderctx;
266    return decoder_inst;
267 err:
268    ossl_decoder_instance_free(decoder_inst);
269    return NULL;
270}
271
272void ossl_decoder_instance_free(OSSL_DECODER_INSTANCE *decoder_inst)
273{
274    if (decoder_inst != NULL) {
275        if (decoder_inst->decoder != NULL)
276            decoder_inst->decoder->freectx(decoder_inst->decoderctx);
277        decoder_inst->decoderctx = NULL;
278        OSSL_DECODER_free(decoder_inst->decoder);
279        decoder_inst->decoder = NULL;
280        OPENSSL_free(decoder_inst);
281    }
282}
283
284int ossl_decoder_ctx_add_decoder_inst(OSSL_DECODER_CTX *ctx,
285                                      OSSL_DECODER_INSTANCE *di)
286{
287    int ok;
288
289    if (ctx->decoder_insts == NULL
290        && (ctx->decoder_insts =
291            sk_OSSL_DECODER_INSTANCE_new_null()) == NULL) {
292        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_MALLOC_FAILURE);
293        return 0;
294    }
295
296    ok = (sk_OSSL_DECODER_INSTANCE_push(ctx->decoder_insts, di) > 0);
297    if (ok) {
298        OSSL_TRACE_BEGIN(DECODER) {
299            BIO_printf(trc_out,
300                       "(ctx %p) Added decoder instance %p for decoder %p\n"
301                       "    %s with %s\n",
302                       (void *)ctx, (void *)di, (void *)di->decoder,
303                       OSSL_DECODER_get0_name(di->decoder),
304                       OSSL_DECODER_get0_properties(di->decoder));
305        } OSSL_TRACE_END(DECODER);
306    }
307    return ok;
308}
309
310int OSSL_DECODER_CTX_add_decoder(OSSL_DECODER_CTX *ctx, OSSL_DECODER *decoder)
311{
312    OSSL_DECODER_INSTANCE *decoder_inst = NULL;
313    const OSSL_PROVIDER *prov = NULL;
314    void *decoderctx = NULL;
315    void *provctx = NULL;
316
317    if (!ossl_assert(ctx != NULL) || !ossl_assert(decoder != NULL)) {
318        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
319        return 0;
320    }
321
322    prov = OSSL_DECODER_get0_provider(decoder);
323    provctx = OSSL_PROVIDER_get0_provider_ctx(prov);
324
325    if ((decoderctx = decoder->newctx(provctx)) == NULL
326        || (decoder_inst =
327            ossl_decoder_instance_new(decoder, decoderctx)) == NULL)
328        goto err;
329    /* Avoid double free of decoderctx on further errors */
330    decoderctx = NULL;
331
332    if (!ossl_decoder_ctx_add_decoder_inst(ctx, decoder_inst))
333        goto err;
334
335    return 1;
336 err:
337    ossl_decoder_instance_free(decoder_inst);
338    if (decoderctx != NULL)
339        decoder->freectx(decoderctx);
340    return 0;
341}
342
343struct collect_extra_decoder_data_st {
344    OSSL_DECODER_CTX *ctx;
345    const char *output_type;
346    /*
347     * 0 to check that the decoder's input type is the same as the decoder name
348     * 1 to check that the decoder's input type differs from the decoder name
349     */
350    enum { IS_SAME = 0, IS_DIFFERENT = 1 } type_check;
351    size_t w_prev_start, w_prev_end; /* "previous" decoders */
352    size_t w_new_start, w_new_end;   /* "new" decoders */
353};
354
355DEFINE_STACK_OF(OSSL_DECODER)
356
357static void collect_all_decoders(OSSL_DECODER *decoder, void *arg)
358{
359    STACK_OF(OSSL_DECODER) *skdecoders = arg;
360
361    if (OSSL_DECODER_up_ref(decoder)
362            && !sk_OSSL_DECODER_push(skdecoders, decoder))
363        OSSL_DECODER_free(decoder);
364}
365
366static void collect_extra_decoder(OSSL_DECODER *decoder, void *arg)
367{
368    struct collect_extra_decoder_data_st *data = arg;
369    size_t j;
370    const OSSL_PROVIDER *prov = OSSL_DECODER_get0_provider(decoder);
371    void *provctx = OSSL_PROVIDER_get0_provider_ctx(prov);
372
373    if (OSSL_DECODER_is_a(decoder, data->output_type)) {
374        void *decoderctx = NULL;
375        OSSL_DECODER_INSTANCE *di = NULL;
376
377        OSSL_TRACE_BEGIN(DECODER) {
378            BIO_printf(trc_out,
379                       "(ctx %p) [%d] Checking out decoder %p:\n"
380                       "    %s with %s\n",
381                       (void *)data->ctx, data->type_check, (void *)decoder,
382                       OSSL_DECODER_get0_name(decoder),
383                       OSSL_DECODER_get0_properties(decoder));
384        } OSSL_TRACE_END(DECODER);
385
386        /*
387         * Check that we don't already have this decoder in our stack,
388         * starting with the previous windows but also looking at what
389         * we have added in the current window.
390         */
391        for (j = data->w_prev_start; j < data->w_new_end; j++) {
392            OSSL_DECODER_INSTANCE *check_inst =
393                sk_OSSL_DECODER_INSTANCE_value(data->ctx->decoder_insts, j);
394
395            if (decoder->base.algodef == check_inst->decoder->base.algodef) {
396                /* We found it, so don't do anything more */
397                OSSL_TRACE_BEGIN(DECODER) {
398                    BIO_printf(trc_out,
399                               "    REJECTED: already exists in the chain\n");
400                } OSSL_TRACE_END(DECODER);
401                return;
402            }
403        }
404
405        if ((decoderctx = decoder->newctx(provctx)) == NULL)
406            return;
407
408        if ((di = ossl_decoder_instance_new(decoder, decoderctx)) == NULL) {
409            decoder->freectx(decoderctx);
410            return;
411        }
412
413        switch (data->type_check) {
414        case IS_SAME:
415            /* If it differs, this is not a decoder to add for now. */
416            if (!OSSL_DECODER_is_a(decoder,
417                                   OSSL_DECODER_INSTANCE_get_input_type(di))) {
418                ossl_decoder_instance_free(di);
419                OSSL_TRACE_BEGIN(DECODER) {
420                    BIO_printf(trc_out,
421                               "    REJECTED: input type doesn't match output type\n");
422                } OSSL_TRACE_END(DECODER);
423                return;
424            }
425            break;
426        case IS_DIFFERENT:
427            /* If it's the same, this is not a decoder to add for now. */
428            if (OSSL_DECODER_is_a(decoder,
429                                  OSSL_DECODER_INSTANCE_get_input_type(di))) {
430                ossl_decoder_instance_free(di);
431                OSSL_TRACE_BEGIN(DECODER) {
432                    BIO_printf(trc_out,
433                               "    REJECTED: input type matches output type\n");
434                } OSSL_TRACE_END(DECODER);
435                return;
436            }
437            break;
438        }
439
440        /*
441         * Apart from keeping w_new_end up to date, We don't care about
442         * errors here.  If it doesn't collect, then it doesn't...
443         */
444        if (!ossl_decoder_ctx_add_decoder_inst(data->ctx, di)) {
445            ossl_decoder_instance_free(di);
446            return;
447        }
448
449        data->w_new_end++;
450    }
451}
452
453int OSSL_DECODER_CTX_add_extra(OSSL_DECODER_CTX *ctx,
454                               OSSL_LIB_CTX *libctx, const char *propq)
455{
456    /*
457     * This function goes through existing decoder methods in
458     * |ctx->decoder_insts|, and tries to fetch new decoders that produce
459     * what the existing ones want as input, and push those newly fetched
460     * decoders on top of the same stack.
461     * Then it does the same again, but looping over the newly fetched
462     * decoders, until there are no more decoders to be fetched, or
463     * when we have done this 10 times.
464     *
465     * we do this with sliding windows on the stack by keeping track of indexes
466     * and of the end.
467     *
468     * +----------------+
469     * |   DER to RSA   | <--- w_prev_start
470     * +----------------+
471     * |   DER to DSA   |
472     * +----------------+
473     * |   DER to DH    |
474     * +----------------+
475     * |   PEM to DER   | <--- w_prev_end, w_new_start
476     * +----------------+
477     *                    <--- w_new_end
478     */
479    struct collect_extra_decoder_data_st data;
480    size_t depth = 0; /* Counts the number of iterations */
481    size_t count; /* Calculates how many were added in each iteration */
482    size_t numdecoders;
483    STACK_OF(OSSL_DECODER) *skdecoders;
484
485    if (!ossl_assert(ctx != NULL)) {
486        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
487        return 0;
488    }
489
490    /*
491     * If there is no stack of OSSL_DECODER_INSTANCE, we have nothing
492     * more to add.  That's fine.
493     */
494    if (ctx->decoder_insts == NULL)
495        return 1;
496
497    OSSL_TRACE_BEGIN(DECODER) {
498        BIO_printf(trc_out, "(ctx %p) Looking for extra decoders\n",
499                   (void *)ctx);
500    } OSSL_TRACE_END(DECODER);
501
502
503    skdecoders = sk_OSSL_DECODER_new_null();
504    if (skdecoders == NULL) {
505        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_MALLOC_FAILURE);
506        return 0;
507    }
508    OSSL_DECODER_do_all_provided(libctx, collect_all_decoders, skdecoders);
509    numdecoders = sk_OSSL_DECODER_num(skdecoders);
510
511    memset(&data, 0, sizeof(data));
512    data.ctx = ctx;
513    data.w_prev_start = 0;
514    data.w_prev_end = sk_OSSL_DECODER_INSTANCE_num(ctx->decoder_insts);
515    do {
516        size_t i, j;
517
518        data.w_new_start = data.w_new_end = data.w_prev_end;
519
520        /*
521         * Two iterations:
522         * 0.  All decoders that have the same name as their input type.
523         *     This allows for decoders that unwrap some data in a specific
524         *     encoding, and pass the result on with the same encoding.
525         * 1.  All decoders that a different name than their input type.
526         */
527        for (data.type_check = IS_SAME;
528             data.type_check <= IS_DIFFERENT;
529             data.type_check++) {
530            for (i = data.w_prev_start; i < data.w_prev_end; i++) {
531                OSSL_DECODER_INSTANCE *decoder_inst =
532                    sk_OSSL_DECODER_INSTANCE_value(ctx->decoder_insts, i);
533
534                data.output_type
535                    = OSSL_DECODER_INSTANCE_get_input_type(decoder_inst);
536
537
538                for (j = 0; j < numdecoders; j++)
539                    collect_extra_decoder(sk_OSSL_DECODER_value(skdecoders, j),
540                                          &data);
541            }
542        }
543        /* How many were added in this iteration */
544        count = data.w_new_end - data.w_new_start;
545
546        /* Slide the "previous decoder" windows */
547        data.w_prev_start = data.w_new_start;
548        data.w_prev_end = data.w_new_end;
549
550        depth++;
551    } while (count != 0 && depth <= 10);
552
553    sk_OSSL_DECODER_pop_free(skdecoders, OSSL_DECODER_free);
554    return 1;
555}
556
557int OSSL_DECODER_CTX_get_num_decoders(OSSL_DECODER_CTX *ctx)
558{
559    if (ctx == NULL || ctx->decoder_insts == NULL)
560        return 0;
561    return sk_OSSL_DECODER_INSTANCE_num(ctx->decoder_insts);
562}
563
564int OSSL_DECODER_CTX_set_construct(OSSL_DECODER_CTX *ctx,
565                                   OSSL_DECODER_CONSTRUCT *construct)
566{
567    if (!ossl_assert(ctx != NULL)) {
568        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
569        return 0;
570    }
571    ctx->construct = construct;
572    return 1;
573}
574
575int OSSL_DECODER_CTX_set_construct_data(OSSL_DECODER_CTX *ctx,
576                                        void *construct_data)
577{
578    if (!ossl_assert(ctx != NULL)) {
579        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
580        return 0;
581    }
582    ctx->construct_data = construct_data;
583    return 1;
584}
585
586int OSSL_DECODER_CTX_set_cleanup(OSSL_DECODER_CTX *ctx,
587                                 OSSL_DECODER_CLEANUP *cleanup)
588{
589    if (!ossl_assert(ctx != NULL)) {
590        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
591        return 0;
592    }
593    ctx->cleanup = cleanup;
594    return 1;
595}
596
597OSSL_DECODER_CONSTRUCT *
598OSSL_DECODER_CTX_get_construct(OSSL_DECODER_CTX *ctx)
599{
600    if (ctx == NULL)
601        return NULL;
602    return ctx->construct;
603}
604
605void *OSSL_DECODER_CTX_get_construct_data(OSSL_DECODER_CTX *ctx)
606{
607    if (ctx == NULL)
608        return NULL;
609    return ctx->construct_data;
610}
611
612OSSL_DECODER_CLEANUP *
613OSSL_DECODER_CTX_get_cleanup(OSSL_DECODER_CTX *ctx)
614{
615    if (ctx == NULL)
616        return NULL;
617    return ctx->cleanup;
618}
619
620int OSSL_DECODER_export(OSSL_DECODER_INSTANCE *decoder_inst,
621                        void *reference, size_t reference_sz,
622                        OSSL_CALLBACK *export_cb, void *export_cbarg)
623{
624    OSSL_DECODER *decoder = NULL;
625    void *decoderctx = NULL;
626
627    if (!(ossl_assert(decoder_inst != NULL)
628          && ossl_assert(reference != NULL)
629          && ossl_assert(export_cb != NULL)
630          && ossl_assert(export_cbarg != NULL))) {
631        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_PASSED_NULL_PARAMETER);
632        return 0;
633    }
634
635    decoder = OSSL_DECODER_INSTANCE_get_decoder(decoder_inst);
636    decoderctx = OSSL_DECODER_INSTANCE_get_decoder_ctx(decoder_inst);
637    return decoder->export_object(decoderctx, reference, reference_sz,
638                                  export_cb, export_cbarg);
639}
640
641OSSL_DECODER *
642OSSL_DECODER_INSTANCE_get_decoder(OSSL_DECODER_INSTANCE *decoder_inst)
643{
644    if (decoder_inst == NULL)
645        return NULL;
646    return decoder_inst->decoder;
647}
648
649void *
650OSSL_DECODER_INSTANCE_get_decoder_ctx(OSSL_DECODER_INSTANCE *decoder_inst)
651{
652    if (decoder_inst == NULL)
653        return NULL;
654    return decoder_inst->decoderctx;
655}
656
657const char *
658OSSL_DECODER_INSTANCE_get_input_type(OSSL_DECODER_INSTANCE *decoder_inst)
659{
660    if (decoder_inst == NULL)
661        return NULL;
662    return decoder_inst->input_type;
663}
664
665const char *
666OSSL_DECODER_INSTANCE_get_input_structure(OSSL_DECODER_INSTANCE *decoder_inst,
667                                          int *was_set)
668{
669    if (decoder_inst == NULL)
670        return NULL;
671    *was_set = decoder_inst->flag_input_structure_was_set;
672    return decoder_inst->input_structure;
673}
674
675static int decoder_process(const OSSL_PARAM params[], void *arg)
676{
677    struct decoder_process_data_st *data = arg;
678    OSSL_DECODER_CTX *ctx = data->ctx;
679    OSSL_DECODER_INSTANCE *decoder_inst = NULL;
680    OSSL_DECODER *decoder = NULL;
681    OSSL_CORE_BIO *cbio = NULL;
682    BIO *bio = data->bio;
683    long loc;
684    size_t i;
685    int ok = 0;
686    /* For recursions */
687    struct decoder_process_data_st new_data;
688    const char *data_type = NULL;
689    const char *data_structure = NULL;
690
691    /*
692     * This is an indicator up the call stack that something was indeed
693     * decoded, leading to a recursive call of this function.
694     */
695    data->flag_next_level_called = 1;
696
697    memset(&new_data, 0, sizeof(new_data));
698    new_data.ctx = data->ctx;
699    new_data.recursion = data->recursion + 1;
700
701#define LEVEL_STR ">>>>>>>>>>>>>>>>"
702#define LEVEL (new_data.recursion < sizeof(LEVEL_STR)                   \
703               ? &LEVEL_STR[sizeof(LEVEL_STR) - new_data.recursion - 1] \
704               : LEVEL_STR "...")
705
706    if (params == NULL) {
707        /* First iteration, where we prepare for what is to come */
708
709        OSSL_TRACE_BEGIN(DECODER) {
710            BIO_printf(trc_out,
711                       "(ctx %p) starting to walk the decoder chain\n",
712                       (void *)new_data.ctx);
713        } OSSL_TRACE_END(DECODER);
714
715        data->current_decoder_inst_index =
716            OSSL_DECODER_CTX_get_num_decoders(ctx);
717
718        bio = data->bio;
719    } else {
720        const OSSL_PARAM *p;
721        const char *trace_data_structure;
722
723        decoder_inst =
724            sk_OSSL_DECODER_INSTANCE_value(ctx->decoder_insts,
725                                           data->current_decoder_inst_index);
726        decoder = OSSL_DECODER_INSTANCE_get_decoder(decoder_inst);
727
728        data->flag_construct_called = 0;
729        if (ctx->construct != NULL) {
730            int rv;
731
732            OSSL_TRACE_BEGIN(DECODER) {
733                BIO_printf(trc_out,
734                           "(ctx %p) %s Running constructor\n",
735                           (void *)new_data.ctx, LEVEL);
736            } OSSL_TRACE_END(DECODER);
737
738            rv = ctx->construct(decoder_inst, params, ctx->construct_data);
739
740            OSSL_TRACE_BEGIN(DECODER) {
741                BIO_printf(trc_out,
742                           "(ctx %p) %s Running constructor => %d\n",
743                           (void *)new_data.ctx, LEVEL, rv);
744            } OSSL_TRACE_END(DECODER);
745
746            data->flag_construct_called = 1;
747            ok = (rv > 0);
748            if (ok)
749                goto end;
750        }
751
752        /* The constructor didn't return success */
753
754        /*
755         * so we try to use the object we got and feed it to any next
756         * decoder that will take it.  Object references are not
757         * allowed for this.
758         * If this data isn't present, decoding has failed.
759         */
760
761        p = OSSL_PARAM_locate_const(params, OSSL_OBJECT_PARAM_DATA);
762        if (p == NULL || p->data_type != OSSL_PARAM_OCTET_STRING)
763            goto end;
764        new_data.bio = BIO_new_mem_buf(p->data, (int)p->data_size);
765        if (new_data.bio == NULL)
766            goto end;
767        bio = new_data.bio;
768
769        /* Get the data type if there is one */
770        p = OSSL_PARAM_locate_const(params, OSSL_OBJECT_PARAM_DATA_TYPE);
771        if (p != NULL && !OSSL_PARAM_get_utf8_string_ptr(p, &data_type))
772            goto end;
773
774        /* Get the data structure if there is one */
775        p = OSSL_PARAM_locate_const(params, OSSL_OBJECT_PARAM_DATA_STRUCTURE);
776        if (p != NULL && !OSSL_PARAM_get_utf8_string_ptr(p, &data_structure))
777            goto end;
778
779        /*
780         * If the data structure is "type-specific" and the data type is
781         * given, we drop the data structure.  The reasoning is that the
782         * data type is already enough to find the applicable next decoder,
783         * so an additional "type-specific" data structure is extraneous.
784         *
785         * Furthermore, if the OSSL_DECODER caller asked for a type specific
786         * structure under another name, such as "DH", we get a mismatch
787         * if the data structure we just received is "type-specific".
788         * There's only so much you can do without infusing this code with
789         * too special knowledge.
790         */
791        trace_data_structure = data_structure;
792        if (data_type != NULL && data_structure != NULL
793            && OPENSSL_strcasecmp(data_structure, "type-specific") == 0)
794            data_structure = NULL;
795
796        OSSL_TRACE_BEGIN(DECODER) {
797            BIO_printf(trc_out,
798                       "(ctx %p) %s incoming from previous decoder (%p):\n"
799                       "    data type: %s, data structure: %s%s\n",
800                       (void *)new_data.ctx, LEVEL, (void *)decoder,
801                       data_type, trace_data_structure,
802                       (trace_data_structure == data_structure
803                        ? "" : " (dropped)"));
804        } OSSL_TRACE_END(DECODER);
805    }
806
807    /*
808     * If we have no more decoders to look through at this point,
809     * we failed
810     */
811    if (data->current_decoder_inst_index == 0)
812        goto end;
813
814    if ((loc = BIO_tell(bio)) < 0) {
815        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_BIO_LIB);
816        goto end;
817    }
818
819    if ((cbio = ossl_core_bio_new_from_bio(bio)) == NULL) {
820        ERR_raise(ERR_LIB_OSSL_DECODER, ERR_R_MALLOC_FAILURE);
821        goto end;
822    }
823
824    for (i = data->current_decoder_inst_index; i-- > 0;) {
825        OSSL_DECODER_INSTANCE *new_decoder_inst =
826            sk_OSSL_DECODER_INSTANCE_value(ctx->decoder_insts, i);
827        OSSL_DECODER *new_decoder =
828            OSSL_DECODER_INSTANCE_get_decoder(new_decoder_inst);
829        void *new_decoderctx =
830            OSSL_DECODER_INSTANCE_get_decoder_ctx(new_decoder_inst);
831        const char *new_input_type =
832            OSSL_DECODER_INSTANCE_get_input_type(new_decoder_inst);
833        int n_i_s_was_set = 0;   /* We don't care here */
834        const char *new_input_structure =
835            OSSL_DECODER_INSTANCE_get_input_structure(new_decoder_inst,
836                                                      &n_i_s_was_set);
837
838        OSSL_TRACE_BEGIN(DECODER) {
839            BIO_printf(trc_out,
840                       "(ctx %p) %s [%u] Considering decoder instance %p (decoder %p):\n"
841                       "    %s with %s\n",
842                       (void *)new_data.ctx, LEVEL, (unsigned int)i,
843                       (void *)new_decoder_inst, (void *)new_decoder,
844                       OSSL_DECODER_get0_name(new_decoder),
845                       OSSL_DECODER_get0_properties(new_decoder));
846        } OSSL_TRACE_END(DECODER);
847
848        /*
849         * If |decoder| is NULL, it means we've just started, and the caller
850         * may have specified what it expects the initial input to be.  If
851         * that's the case, we do this extra check.
852         */
853        if (decoder == NULL && ctx->start_input_type != NULL
854            && OPENSSL_strcasecmp(ctx->start_input_type, new_input_type) != 0) {
855            OSSL_TRACE_BEGIN(DECODER) {
856                BIO_printf(trc_out,
857                           "(ctx %p) %s [%u] the start input type '%s' doesn't match the input type of the considered decoder, skipping...\n",
858                           (void *)new_data.ctx, LEVEL, (unsigned int)i,
859                           ctx->start_input_type);
860            } OSSL_TRACE_END(DECODER);
861            continue;
862        }
863
864        /*
865         * If we have a previous decoder, we check that the input type
866         * of the next to be used matches the type of this previous one.
867         * |new_input_type| holds the value of the "input-type" parameter
868         * for the decoder we're currently considering.
869         */
870        if (decoder != NULL && !OSSL_DECODER_is_a(decoder, new_input_type)) {
871            OSSL_TRACE_BEGIN(DECODER) {
872                BIO_printf(trc_out,
873                           "(ctx %p) %s [%u] the input type doesn't match the name of the previous decoder (%p), skipping...\n",
874                           (void *)new_data.ctx, LEVEL, (unsigned int)i,
875                           (void *)decoder);
876            } OSSL_TRACE_END(DECODER);
877            continue;
878        }
879
880        /*
881         * If the previous decoder gave us a data type, we check to see
882         * if that matches the decoder we're currently considering.
883         */
884        if (data_type != NULL && !OSSL_DECODER_is_a(new_decoder, data_type)) {
885            OSSL_TRACE_BEGIN(DECODER) {
886                BIO_printf(trc_out,
887                           "(ctx %p) %s [%u] the previous decoder's data type doesn't match the name of the considered decoder, skipping...\n",
888                           (void *)new_data.ctx, LEVEL, (unsigned int)i);
889            } OSSL_TRACE_END(DECODER);
890            continue;
891        }
892
893        /*
894         * If the previous decoder gave us a data structure name, we check
895         * to see that it matches the input data structure of the decoder
896         * we're currently considering.
897         */
898        if (data_structure != NULL
899            && (new_input_structure == NULL
900                || OPENSSL_strcasecmp(data_structure,
901                                      new_input_structure) != 0)) {
902            OSSL_TRACE_BEGIN(DECODER) {
903                BIO_printf(trc_out,
904                           "(ctx %p) %s [%u] the previous decoder's data structure doesn't match the input structure of the considered decoder, skipping...\n",
905                           (void *)new_data.ctx, LEVEL, (unsigned int)i);
906            } OSSL_TRACE_END(DECODER);
907            continue;
908        }
909
910        /*
911         * If the decoder we're currently considering specifies a structure,
912         * and this check hasn't already been done earlier in this chain of
913         * decoder_process() calls, check that it matches the user provided
914         * input structure, if one is given.
915         */
916        if (!data->flag_input_structure_checked
917            && ctx->input_structure != NULL
918            && new_input_structure != NULL) {
919            data->flag_input_structure_checked = 1;
920            if (OPENSSL_strcasecmp(new_input_structure,
921                                   ctx->input_structure) != 0) {
922                OSSL_TRACE_BEGIN(DECODER) {
923                    BIO_printf(trc_out,
924                               "(ctx %p) %s [%u] the previous decoder's data structure doesn't match the input structure given by the user, skipping...\n",
925                               (void *)new_data.ctx, LEVEL, (unsigned int)i);
926                } OSSL_TRACE_END(DECODER);
927                continue;
928            }
929        }
930
931        /*
932         * Checking the return value of BIO_reset() or BIO_seek() is unsafe.
933         * Furthermore, BIO_reset() is unsafe to use if the source BIO happens
934         * to be a BIO_s_mem(), because the earlier BIO_tell() gives us zero
935         * no matter where we are in the underlying buffer we're reading from.
936         *
937         * So, we simply do a BIO_seek(), and use BIO_tell() that we're back
938         * at the same position.  This is a best effort attempt, but BIO_seek()
939         * and BIO_tell() should come as a pair...
940         */
941        (void)BIO_seek(bio, loc);
942        if (BIO_tell(bio) != loc)
943            goto end;
944
945        /* Recurse */
946        OSSL_TRACE_BEGIN(DECODER) {
947            BIO_printf(trc_out,
948                       "(ctx %p) %s [%u] Running decoder instance %p\n",
949                       (void *)new_data.ctx, LEVEL, (unsigned int)i,
950                       (void *)new_decoder_inst);
951        } OSSL_TRACE_END(DECODER);
952
953        /*
954         * We only care about errors reported from decoder implementations
955         * if it returns false (i.e. there was a fatal error).
956         */
957        ERR_set_mark();
958
959        new_data.current_decoder_inst_index = i;
960        new_data.flag_input_structure_checked
961            = data->flag_input_structure_checked;
962        ok = new_decoder->decode(new_decoderctx, cbio,
963                                 new_data.ctx->selection,
964                                 decoder_process, &new_data,
965                                 ossl_pw_passphrase_callback_dec,
966                                 &new_data.ctx->pwdata);
967
968        OSSL_TRACE_BEGIN(DECODER) {
969            BIO_printf(trc_out,
970                       "(ctx %p) %s [%u] Running decoder instance %p => %d"
971                       " (recursed further: %s, construct called: %s)\n",
972                       (void *)new_data.ctx, LEVEL, (unsigned int)i,
973                       (void *)new_decoder_inst, ok,
974                       new_data.flag_next_level_called ? "yes" : "no",
975                       new_data.flag_construct_called ? "yes" : "no");
976        } OSSL_TRACE_END(DECODER);
977
978        data->flag_construct_called = new_data.flag_construct_called;
979
980        /* Break on error or if we tried to construct an object already */
981        if (!ok || data->flag_construct_called) {
982            ERR_clear_last_mark();
983            break;
984        }
985        ERR_pop_to_mark();
986
987        /*
988         * Break if the decoder implementation that we called recursed, since
989         * that indicates that it successfully decoded something.
990         */
991        if (new_data.flag_next_level_called)
992            break;
993    }
994
995 end:
996    ossl_core_bio_free(cbio);
997    BIO_free(new_data.bio);
998    return ok;
999}
1000