1 /*
2  * Copyright 2001-2023 The OpenSSL Project Authors. All Rights Reserved.
3  * Copyright Siemens AG 2018-2020
4  *
5  * Licensed under the Apache License 2.0 (the "License").  You may not use
6  * this file except in compliance with the License.  You can obtain a copy
7  * in the file LICENSE in the source distribution or at
8  * https://www.openssl.org/source/license.html
9  */
10 
11 #include "e_os.h"
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include "crypto/ctype.h"
15 #include <string.h>
16 #include <openssl/asn1.h>
17 #include <openssl/evp.h>
18 #include <openssl/err.h>
19 #include <openssl/httperr.h>
20 #include <openssl/cmperr.h>
21 #include <openssl/buffer.h>
22 #include <openssl/http.h>
23 #include "internal/sockets.h"
24 #include "internal/cryptlib.h" /* for ossl_assert() */
25 
26 #define HAS_PREFIX(str, prefix) (strncmp(str, prefix, sizeof(prefix) - 1) == 0)
27 #define HTTP_PREFIX "HTTP/"
28 #define HTTP_VERSION_PATT "1." /* allow 1.x */
29 #define HTTP_VERSION_STR_LEN sizeof(HTTP_VERSION_PATT) /* == strlen("1.0") */
30 #define HTTP_PREFIX_VERSION HTTP_PREFIX""HTTP_VERSION_PATT
31 #define HTTP_1_0 HTTP_PREFIX_VERSION"0" /* "HTTP/1.0" */
32 #define HTTP_LINE1_MINLEN (sizeof(HTTP_PREFIX_VERSION "x 200\n") - 1)
33 #define HTTP_VERSION_MAX_REDIRECTIONS 50
34 
35 #define HTTP_STATUS_CODE_OK                200
36 #define HTTP_STATUS_CODE_MOVED_PERMANENTLY 301
37 #define HTTP_STATUS_CODE_FOUND             302
38 
39 /* Stateful HTTP request code, supporting blocking and non-blocking I/O */
40 
41 /* Opaque HTTP request status structure */
42 
43 struct ossl_http_req_ctx_st {
44     int state;                  /* Current I/O state */
45     unsigned char *buf;         /* Buffer to write request or read response */
46     int buf_size;               /* Buffer size */
47     int free_wbio;              /* wbio allocated internally, free with ctx */
48     BIO *wbio;                  /* BIO to write/send request to */
49     BIO *rbio;                  /* BIO to read/receive response from */
50     OSSL_HTTP_bio_cb_t upd_fn;  /* Optional BIO update callback used for TLS */
51     void *upd_arg;              /* Optional arg for update callback function */
52     int use_ssl;                /* Use HTTPS */
53     char *proxy;                /* Optional proxy name or URI */
54     char *server;               /* Optional server host name */
55     char *port;                 /* Optional server port */
56     BIO *mem;                   /* Mem BIO holding request header or response */
57     BIO *req;                   /* BIO holding the request provided by caller */
58     int method_POST;            /* HTTP method is POST (else GET) */
59     char *expected_ct;          /* Optional expected Content-Type */
60     int expect_asn1;            /* Response must be ASN.1-encoded */
61     unsigned char *pos;         /* Current position sending data */
62     long len_to_send;           /* Number of bytes still to send */
63     size_t resp_len;            /* Length of response */
64     size_t max_resp_len;        /* Maximum length of response, or 0 */
65     int keep_alive;             /* Persistent conn. 0=no, 1=prefer, 2=require */
66     time_t max_time;            /* Maximum end time of current transfer, or 0 */
67     time_t max_total_time;      /* Maximum end time of total transfer, or 0 */
68     char *redirection_url;      /* Location obtained from HTTP status 301/302 */
69 };
70 
71 /* HTTP states */
72 
73 #define OHS_NOREAD         0x1000 /* If set no reading should be performed */
74 #define OHS_ERROR          (0 | OHS_NOREAD) /* Error condition */
75 #define OHS_ADD_HEADERS    (1 | OHS_NOREAD) /* Adding header lines to request */
76 #define OHS_WRITE_INIT     (2 | OHS_NOREAD) /* 1st call: ready to start send */
77 #define OHS_WRITE_HDR      (3 | OHS_NOREAD) /* Request header being sent */
78 #define OHS_WRITE_REQ      (4 | OHS_NOREAD) /* Request contents being sent */
79 #define OHS_FLUSH          (5 | OHS_NOREAD) /* Request being flushed */
80 #define OHS_FIRSTLINE       1 /* First line of response being read */
81 #define OHS_HEADERS         2 /* MIME headers of response being read */
82 #define OHS_REDIRECT        3 /* MIME headers being read, expecting Location */
83 #define OHS_ASN1_HEADER     4 /* ASN1 sequence header (tag+length) being read */
84 #define OHS_ASN1_CONTENT    5 /* ASN1 content octets being read */
85 #define OHS_ASN1_DONE      (6 | OHS_NOREAD) /* ASN1 content read completed */
86 #define OHS_STREAM         (7 | OHS_NOREAD) /* HTTP content stream to be read */
87 
88 /* Low-level HTTP API implementation */
89 
90 OSSL_HTTP_REQ_CTX *OSSL_HTTP_REQ_CTX_new(BIO *wbio, BIO *rbio, int buf_size)
91 {
92     OSSL_HTTP_REQ_CTX *rctx;
93 
94     if (wbio == NULL || rbio == NULL) {
95         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
96         return NULL;
97     }
98 
99     if ((rctx = OPENSSL_zalloc(sizeof(*rctx))) == NULL)
100         return NULL;
101     rctx->state = OHS_ERROR;
102     rctx->buf_size = buf_size > 0 ? buf_size : OSSL_HTTP_DEFAULT_MAX_LINE_LEN;
103     rctx->buf = OPENSSL_malloc(rctx->buf_size);
104     rctx->wbio = wbio;
105     rctx->rbio = rbio;
106     if (rctx->buf == NULL) {
107         OPENSSL_free(rctx);
108         return NULL;
109     }
110     rctx->max_resp_len = OSSL_HTTP_DEFAULT_MAX_RESP_LEN;
111     /* everything else is 0, e.g. rctx->len_to_send, or NULL, e.g. rctx->mem  */
112     return rctx;
113 }
114 
115 void OSSL_HTTP_REQ_CTX_free(OSSL_HTTP_REQ_CTX *rctx)
116 {
117     if (rctx == NULL)
118         return;
119     /*
120      * Use BIO_free_all() because bio_update_fn may prepend or append to cbio.
121      * This also frees any (e.g., SSL/TLS) BIOs linked with bio and,
122      * like BIO_reset(bio), calls SSL_shutdown() to notify/alert the peer.
123      */
124     if (rctx->free_wbio)
125         BIO_free_all(rctx->wbio);
126     /* do not free rctx->rbio */
127     BIO_free(rctx->mem);
128     BIO_free(rctx->req);
129     OPENSSL_free(rctx->buf);
130     OPENSSL_free(rctx->proxy);
131     OPENSSL_free(rctx->server);
132     OPENSSL_free(rctx->port);
133     OPENSSL_free(rctx->expected_ct);
134     OPENSSL_free(rctx);
135 }
136 
137 BIO *OSSL_HTTP_REQ_CTX_get0_mem_bio(const OSSL_HTTP_REQ_CTX *rctx)
138 {
139     if (rctx == NULL) {
140         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
141         return NULL;
142     }
143     return rctx->mem;
144 }
145 
146 size_t OSSL_HTTP_REQ_CTX_get_resp_len(const OSSL_HTTP_REQ_CTX *rctx)
147 {
148     if (rctx == NULL) {
149         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
150         return 0;
151     }
152     return rctx->resp_len;
153 }
154 
155 void OSSL_HTTP_REQ_CTX_set_max_response_length(OSSL_HTTP_REQ_CTX *rctx,
156                                                unsigned long len)
157 {
158     if (rctx == NULL) {
159         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
160         return;
161     }
162     rctx->max_resp_len = len != 0 ? (size_t)len : OSSL_HTTP_DEFAULT_MAX_RESP_LEN;
163 }
164 
165 /*
166  * Create request line using |rctx| and |path| (or "/" in case |path| is NULL).
167  * Server name (and optional port) must be given if and only if
168  * a plain HTTP proxy is used and |path| does not begin with 'http://'.
169  */
170 int OSSL_HTTP_REQ_CTX_set_request_line(OSSL_HTTP_REQ_CTX *rctx, int method_POST,
171                                        const char *server, const char *port,
172                                        const char *path)
173 {
174     if (rctx == NULL) {
175         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
176         return 0;
177     }
178     BIO_free(rctx->mem);
179     if ((rctx->mem = BIO_new(BIO_s_mem())) == NULL)
180         return 0;
181 
182     rctx->method_POST = method_POST != 0;
183     if (BIO_printf(rctx->mem, "%s ", rctx->method_POST ? "POST" : "GET") <= 0)
184         return 0;
185 
186     if (server != NULL) { /* HTTP (but not HTTPS) proxy is used */
187         /*
188          * Section 5.1.2 of RFC 1945 states that the absoluteURI form is only
189          * allowed when using a proxy
190          */
191         if (BIO_printf(rctx->mem, OSSL_HTTP_PREFIX"%s", server) <= 0)
192             return 0;
193         if (port != NULL && BIO_printf(rctx->mem, ":%s", port) <= 0)
194             return 0;
195     }
196 
197     /* Make sure path includes a forward slash (abs_path) */
198     if (path == NULL)  {
199         path = "/";
200     } else if (HAS_PREFIX(path, "http://")) { /* absoluteURI for proxy use */
201         if (server != NULL) {
202             ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_INVALID_ARGUMENT);
203             return 0;
204         }
205     } else if (path[0] != '/' && BIO_printf(rctx->mem, "/") <= 0) {
206         return 0;
207     }
208     /*
209      * Add (the rest of) the path and the HTTP version,
210      * which is fixed to 1.0 for straightforward implementation of keep-alive
211      */
212     if (BIO_printf(rctx->mem, "%s "HTTP_1_0"\r\n", path) <= 0)
213         return 0;
214 
215     rctx->resp_len = 0;
216     rctx->state = OHS_ADD_HEADERS;
217     return 1;
218 }
219 
220 int OSSL_HTTP_REQ_CTX_add1_header(OSSL_HTTP_REQ_CTX *rctx,
221                                   const char *name, const char *value)
222 {
223     if (rctx == NULL || name == NULL) {
224         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
225         return 0;
226     }
227     if (rctx->mem == NULL) {
228         ERR_raise(ERR_LIB_HTTP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
229         return 0;
230     }
231 
232     if (BIO_puts(rctx->mem, name) <= 0)
233         return 0;
234     if (value != NULL) {
235         if (BIO_write(rctx->mem, ": ", 2) != 2)
236             return 0;
237         if (BIO_puts(rctx->mem, value) <= 0)
238             return 0;
239     }
240     return BIO_write(rctx->mem, "\r\n", 2) == 2;
241 }
242 
243 int OSSL_HTTP_REQ_CTX_set_expected(OSSL_HTTP_REQ_CTX *rctx,
244                                    const char *content_type, int asn1,
245                                    int timeout, int keep_alive)
246 {
247     if (rctx == NULL) {
248         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
249         return 0;
250     }
251     if (keep_alive != 0
252             && rctx->state != OHS_ERROR && rctx->state != OHS_ADD_HEADERS) {
253         /* Cannot anymore set keep-alive in request header */
254         ERR_raise(ERR_LIB_HTTP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
255         return 0;
256     }
257 
258     OPENSSL_free(rctx->expected_ct);
259     rctx->expected_ct = NULL;
260     if (content_type != NULL
261             && (rctx->expected_ct = OPENSSL_strdup(content_type)) == NULL)
262         return 0;
263 
264     rctx->expect_asn1 = asn1;
265     if (timeout >= 0)
266         rctx->max_time = timeout > 0 ? time(NULL) + timeout : 0;
267     else /* take over any |overall_timeout| arg of OSSL_HTTP_open(), else 0 */
268         rctx->max_time = rctx->max_total_time;
269     rctx->keep_alive = keep_alive;
270     return 1;
271 }
272 
273 static int set1_content(OSSL_HTTP_REQ_CTX *rctx,
274                         const char *content_type, BIO *req)
275 {
276     long req_len = 0;
277 #ifndef OPENSSL_NO_STDIO
278     FILE *fp = NULL;
279 #endif
280 
281     if (rctx == NULL || (req == NULL && content_type != NULL)) {
282         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
283         return 0;
284     }
285 
286     if (rctx->keep_alive != 0
287             && !OSSL_HTTP_REQ_CTX_add1_header(rctx, "Connection", "keep-alive"))
288         return 0;
289 
290     BIO_free(rctx->req);
291     rctx->req = NULL;
292     if (req == NULL)
293         return 1;
294     if (!rctx->method_POST) {
295         ERR_raise(ERR_LIB_HTTP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
296         return 0;
297     }
298 
299     if (content_type != NULL
300             && BIO_printf(rctx->mem, "Content-Type: %s\r\n", content_type) <= 0)
301         return 0;
302 
303     /*
304      * BIO_CTRL_INFO yields the data length at least for memory BIOs, but for
305      * file-based BIOs it gives the current position, which is not what we need.
306      */
307     if (BIO_method_type(req) == BIO_TYPE_FILE) {
308 #ifndef OPENSSL_NO_STDIO
309         if (BIO_get_fp(req, &fp) == 1 && fseek(fp, 0, SEEK_END) == 0) {
310             req_len = ftell(fp);
311             (void)fseek(fp, 0, SEEK_SET);
312         } else {
313             fp = NULL;
314         }
315 #endif
316     } else {
317         req_len = BIO_ctrl(req, BIO_CTRL_INFO, 0, NULL);
318         /*
319          * Streaming BIOs likely will not support querying the size at all,
320          * and we assume we got a correct value if req_len > 0.
321          */
322     }
323     if ((
324 #ifndef OPENSSL_NO_STDIO
325          fp != NULL /* definitely correct req_len */ ||
326 #endif
327          req_len > 0)
328             && BIO_printf(rctx->mem, "Content-Length: %ld\r\n", req_len) < 0)
329         return 0;
330 
331     if (!BIO_up_ref(req))
332         return 0;
333     rctx->req = req;
334     return 1;
335 }
336 
337 int OSSL_HTTP_REQ_CTX_set1_req(OSSL_HTTP_REQ_CTX *rctx, const char *content_type,
338                                const ASN1_ITEM *it, const ASN1_VALUE *req)
339 {
340     BIO *mem = NULL;
341     int res = 1;
342 
343     if (req != NULL)
344         res = (mem = ASN1_item_i2d_mem_bio(it, req)) != NULL;
345     res = res && set1_content(rctx, content_type, mem);
346     BIO_free(mem);
347     return res;
348 }
349 
350 static int add1_headers(OSSL_HTTP_REQ_CTX *rctx,
351                         const STACK_OF(CONF_VALUE) *headers, const char *host)
352 {
353     int i;
354     int add_host = host != NULL && *host != '\0';
355     CONF_VALUE *hdr;
356 
357     for (i = 0; i < sk_CONF_VALUE_num(headers); i++) {
358         hdr = sk_CONF_VALUE_value(headers, i);
359         if (add_host && OPENSSL_strcasecmp("host", hdr->name) == 0)
360             add_host = 0;
361         if (!OSSL_HTTP_REQ_CTX_add1_header(rctx, hdr->name, hdr->value))
362             return 0;
363     }
364 
365     if (add_host && !OSSL_HTTP_REQ_CTX_add1_header(rctx, "Host", host))
366         return 0;
367     return 1;
368 }
369 
370 /* Create OSSL_HTTP_REQ_CTX structure using the values provided. */
371 static OSSL_HTTP_REQ_CTX *http_req_ctx_new(int free_wbio, BIO *wbio, BIO *rbio,
372                                            OSSL_HTTP_bio_cb_t bio_update_fn,
373                                            void *arg, int use_ssl,
374                                            const char *proxy,
375                                            const char *server, const char *port,
376                                            int buf_size, int overall_timeout)
377 {
378     OSSL_HTTP_REQ_CTX *rctx = OSSL_HTTP_REQ_CTX_new(wbio, rbio, buf_size);
379 
380     if (rctx == NULL)
381         return NULL;
382     rctx->free_wbio = free_wbio;
383     rctx->upd_fn = bio_update_fn;
384     rctx->upd_arg = arg;
385     rctx->use_ssl = use_ssl;
386     if (proxy != NULL
387             && (rctx->proxy = OPENSSL_strdup(proxy)) == NULL)
388         goto err;
389     if (server != NULL
390             && (rctx->server = OPENSSL_strdup(server)) == NULL)
391         goto err;
392     if (port != NULL
393             && (rctx->port = OPENSSL_strdup(port)) == NULL)
394         goto err;
395     rctx->max_total_time =
396         overall_timeout > 0 ? time(NULL) + overall_timeout : 0;
397     return rctx;
398 
399  err:
400     OSSL_HTTP_REQ_CTX_free(rctx);
401     return NULL;
402 }
403 
404 /*
405  * Parse first HTTP response line. This should be like this: "HTTP/1.0 200 OK".
406  * We need to obtain the status code and (optional) informational message.
407  * Return any received HTTP response status code, or 0 on fatal error.
408  */
409 
410 static int parse_http_line1(char *line, int *found_keep_alive)
411 {
412     int i, retcode, err;
413     char *code, *reason, *end;
414 
415     if (!HAS_PREFIX(line, HTTP_PREFIX_VERSION))
416         goto err;
417     /* above HTTP 1.0, connection persistence is the default */
418     *found_keep_alive = line[strlen(HTTP_PREFIX_VERSION)] > '0';
419 
420     /* Skip to first whitespace (past protocol info) */
421     for (code = line; *code != '\0' && !ossl_isspace(*code); code++)
422         continue;
423     if (*code == '\0')
424         goto err;
425 
426     /* Skip past whitespace to start of response code */
427     while (*code != '\0' && ossl_isspace(*code))
428         code++;
429     if (*code == '\0')
430         goto err;
431 
432     /* Find end of response code: first whitespace after start of code */
433     for (reason = code; *reason != '\0' && !ossl_isspace(*reason); reason++)
434         continue;
435 
436     if (*reason == '\0')
437         goto err;
438 
439     /* Set end of response code and start of message */
440     *reason++ = '\0';
441 
442     /* Attempt to parse numeric code */
443     retcode = strtoul(code, &end, 10);
444     if (*end != '\0')
445         goto err;
446 
447     /* Skip over any leading whitespace in message */
448     while (*reason != '\0' && ossl_isspace(*reason))
449         reason++;
450 
451     if (*reason != '\0') {
452         /*
453          * Finally zap any trailing whitespace in message (include CRLF)
454          */
455 
456         /* chop any trailing whitespace from reason */
457         /* We know reason has a non-whitespace character so this is OK */
458         for (end = reason + strlen(reason) - 1; ossl_isspace(*end); end--)
459             *end = '\0';
460     }
461 
462     switch (retcode) {
463     case HTTP_STATUS_CODE_OK:
464     case HTTP_STATUS_CODE_MOVED_PERMANENTLY:
465     case HTTP_STATUS_CODE_FOUND:
466         return retcode;
467     default:
468         err = HTTP_R_RECEIVED_ERROR;
469         if (retcode < 400)
470             err = HTTP_R_STATUS_CODE_UNSUPPORTED;
471         if (*reason == '\0')
472             ERR_raise_data(ERR_LIB_HTTP, err, "code=%s", code);
473         else
474             ERR_raise_data(ERR_LIB_HTTP, err, "code=%s, reason=%s", code,
475                            reason);
476         return retcode;
477     }
478 
479  err:
480     for (i = 0; i < 60 && line[i] != '\0'; i++)
481         if (!ossl_isprint(line[i]))
482             line[i] = ' ';
483     line[i] = '\0';
484     ERR_raise_data(ERR_LIB_HTTP, HTTP_R_HEADER_PARSE_ERROR, "content=%s", line);
485     return 0;
486 }
487 
488 static int check_set_resp_len(OSSL_HTTP_REQ_CTX *rctx, size_t len)
489 {
490     if (rctx->max_resp_len != 0 && len > rctx->max_resp_len)
491         ERR_raise_data(ERR_LIB_HTTP, HTTP_R_MAX_RESP_LEN_EXCEEDED,
492                        "length=%zu, max=%zu", len, rctx->max_resp_len);
493     if (rctx->resp_len != 0 && rctx->resp_len != len)
494         ERR_raise_data(ERR_LIB_HTTP, HTTP_R_INCONSISTENT_CONTENT_LENGTH,
495                        "ASN.1 length=%zu, Content-Length=%zu",
496                        len, rctx->resp_len);
497     rctx->resp_len = len;
498     return 1;
499 }
500 
501 static int may_still_retry(time_t max_time, int *ptimeout)
502 {
503     time_t time_diff, now = time(NULL);
504 
505     if (max_time != 0) {
506         if (max_time < now) {
507             ERR_raise(ERR_LIB_HTTP, HTTP_R_RETRY_TIMEOUT);
508             return 0;
509         }
510         time_diff = max_time - now;
511         *ptimeout = time_diff > INT_MAX ? INT_MAX : (int)time_diff;
512     }
513     return 1;
514 }
515 
516 /*
517  * Try exchanging request and response via HTTP on (non-)blocking BIO in rctx.
518  * Returns 1 on success, 0 on error or redirection, -1 on BIO_should_retry.
519  */
520 int OSSL_HTTP_REQ_CTX_nbio(OSSL_HTTP_REQ_CTX *rctx)
521 {
522     int i, found_expected_ct = 0, found_keep_alive = 0;
523     long n;
524     size_t resp_len;
525     const unsigned char *p;
526     char *buf, *key, *value, *line_end = NULL;
527 
528     if (rctx == NULL) {
529         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
530         return 0;
531     }
532     if (rctx->mem == NULL || rctx->wbio == NULL || rctx->rbio == NULL) {
533         ERR_raise(ERR_LIB_HTTP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
534         return 0;
535     }
536 
537     rctx->redirection_url = NULL;
538  next_io:
539     buf = (char *)rctx->buf;
540     if ((rctx->state & OHS_NOREAD) == 0) {
541         if (rctx->expect_asn1) {
542             n = BIO_read(rctx->rbio, rctx->buf, rctx->buf_size);
543         } else {
544             (void)ERR_set_mark();
545             n = BIO_gets(rctx->rbio, buf, rctx->buf_size);
546             if (n == -2) { /* unsupported method */
547                 (void)ERR_pop_to_mark();
548                 n = BIO_get_line(rctx->rbio, buf, rctx->buf_size);
549             } else {
550                 (void)ERR_clear_last_mark();
551             }
552         }
553         if (n <= 0) {
554             if (BIO_should_retry(rctx->rbio))
555                 return -1;
556             ERR_raise(ERR_LIB_HTTP, HTTP_R_FAILED_READING_DATA);
557             return 0;
558         }
559 
560         /* Write data to memory BIO */
561         if (BIO_write(rctx->mem, rctx->buf, n) != n)
562             return 0;
563     }
564 
565     switch (rctx->state) {
566     case OHS_ADD_HEADERS:
567         /* Last operation was adding headers: need a final \r\n */
568         if (BIO_write(rctx->mem, "\r\n", 2) != 2) {
569             rctx->state = OHS_ERROR;
570             return 0;
571         }
572         rctx->state = OHS_WRITE_INIT;
573 
574         /* fall thru */
575     case OHS_WRITE_INIT:
576         rctx->len_to_send = BIO_get_mem_data(rctx->mem, &rctx->pos);
577         rctx->state = OHS_WRITE_HDR;
578 
579         /* fall thru */
580     case OHS_WRITE_HDR:
581         /* Copy some chunk of data from rctx->mem to rctx->wbio */
582     case OHS_WRITE_REQ:
583         /* Copy some chunk of data from rctx->req to rctx->wbio */
584 
585         if (rctx->len_to_send > 0) {
586             i = BIO_write(rctx->wbio, rctx->pos, rctx->len_to_send);
587             if (i <= 0) {
588                 if (BIO_should_retry(rctx->wbio))
589                     return -1;
590                 rctx->state = OHS_ERROR;
591                 return 0;
592             }
593             rctx->pos += i;
594             rctx->len_to_send -= i;
595             goto next_io;
596         }
597         if (rctx->state == OHS_WRITE_HDR) {
598             (void)BIO_reset(rctx->mem);
599             rctx->state = OHS_WRITE_REQ;
600         }
601         if (rctx->req != NULL && !BIO_eof(rctx->req)) {
602             n = BIO_read(rctx->req, rctx->buf, rctx->buf_size);
603             if (n <= 0) {
604                 if (BIO_should_retry(rctx->req))
605                     return -1;
606                 ERR_raise(ERR_LIB_HTTP, HTTP_R_FAILED_READING_DATA);
607                 return 0;
608             }
609             rctx->pos = rctx->buf;
610             rctx->len_to_send = n;
611             goto next_io;
612         }
613         rctx->state = OHS_FLUSH;
614 
615         /* fall thru */
616     case OHS_FLUSH:
617 
618         i = BIO_flush(rctx->wbio);
619 
620         if (i > 0) {
621             rctx->state = OHS_FIRSTLINE;
622             goto next_io;
623         }
624 
625         if (BIO_should_retry(rctx->wbio))
626             return -1;
627 
628         rctx->state = OHS_ERROR;
629         return 0;
630 
631     case OHS_ERROR:
632         return 0;
633 
634     case OHS_FIRSTLINE:
635     case OHS_HEADERS:
636     case OHS_REDIRECT:
637 
638         /* Attempt to read a line in */
639  next_line:
640         /*
641          * Due to strange memory BIO behavior with BIO_gets we have to check
642          * there's a complete line in there before calling BIO_gets or we'll
643          * just get a partial read.
644          */
645         n = BIO_get_mem_data(rctx->mem, &p);
646         if (n <= 0 || memchr(p, '\n', n) == 0) {
647             if (n >= rctx->buf_size) {
648                 rctx->state = OHS_ERROR;
649                 return 0;
650             }
651             goto next_io;
652         }
653         n = BIO_gets(rctx->mem, buf, rctx->buf_size);
654 
655         if (n <= 0) {
656             if (BIO_should_retry(rctx->mem))
657                 goto next_io;
658             rctx->state = OHS_ERROR;
659             return 0;
660         }
661 
662         /* Don't allow excessive lines */
663         if (n == rctx->buf_size) {
664             ERR_raise(ERR_LIB_HTTP, HTTP_R_RESPONSE_LINE_TOO_LONG);
665             rctx->state = OHS_ERROR;
666             return 0;
667         }
668 
669         /* First line */
670         if (rctx->state == OHS_FIRSTLINE) {
671             switch (parse_http_line1(buf, &found_keep_alive)) {
672             case HTTP_STATUS_CODE_OK:
673                 rctx->state = OHS_HEADERS;
674                 goto next_line;
675             case HTTP_STATUS_CODE_MOVED_PERMANENTLY:
676             case HTTP_STATUS_CODE_FOUND: /* i.e., moved temporarily */
677                 if (!rctx->method_POST) { /* method is GET */
678                     rctx->state = OHS_REDIRECT;
679                     goto next_line;
680                 }
681                 ERR_raise(ERR_LIB_HTTP, HTTP_R_REDIRECTION_NOT_ENABLED);
682                 /* redirection is not supported/recommended for POST */
683                 /* fall through */
684             default:
685                 rctx->state = OHS_ERROR;
686                 goto next_line;
687             }
688         }
689         key = buf;
690         value = strchr(key, ':');
691         if (value != NULL) {
692             *(value++) = '\0';
693             while (ossl_isspace(*value))
694                 value++;
695             line_end = strchr(value, '\r');
696             if (line_end == NULL)
697                 line_end = strchr(value, '\n');
698             if (line_end != NULL)
699                 *line_end = '\0';
700         }
701         if (value != NULL && line_end != NULL) {
702             if (rctx->state == OHS_REDIRECT
703                     && OPENSSL_strcasecmp(key, "Location") == 0) {
704                 rctx->redirection_url = value;
705                 return 0;
706             }
707             if (rctx->state == OHS_HEADERS && rctx->expected_ct != NULL
708                     && OPENSSL_strcasecmp(key, "Content-Type") == 0) {
709                 if (OPENSSL_strcasecmp(rctx->expected_ct, value) != 0) {
710                     ERR_raise_data(ERR_LIB_HTTP, HTTP_R_UNEXPECTED_CONTENT_TYPE,
711                                    "expected=%s, actual=%s",
712                                    rctx->expected_ct, value);
713                     return 0;
714                 }
715                 found_expected_ct = 1;
716             }
717 
718             /* https://tools.ietf.org/html/rfc7230#section-6.3 Persistence */
719             if (OPENSSL_strcasecmp(key, "Connection") == 0) {
720                 if (OPENSSL_strcasecmp(value, "keep-alive") == 0)
721                     found_keep_alive = 1;
722                 else if (OPENSSL_strcasecmp(value, "close") == 0)
723                     found_keep_alive = 0;
724             } else if (OPENSSL_strcasecmp(key, "Content-Length") == 0) {
725                 resp_len = (size_t)strtoul(value, &line_end, 10);
726                 if (line_end == value || *line_end != '\0') {
727                     ERR_raise_data(ERR_LIB_HTTP,
728                                    HTTP_R_ERROR_PARSING_CONTENT_LENGTH,
729                                    "input=%s", value);
730                     return 0;
731                 }
732                 if (!check_set_resp_len(rctx, resp_len))
733                     return 0;
734             }
735         }
736 
737         /* Look for blank line indicating end of headers */
738         for (p = rctx->buf; *p != '\0'; p++) {
739             if (*p != '\r' && *p != '\n')
740                 break;
741         }
742         if (*p != '\0') /* not end of headers */
743             goto next_line;
744 
745         if (rctx->keep_alive != 0 /* do not let server initiate keep_alive */
746                 && !found_keep_alive /* otherwise there is no change */) {
747             if (rctx->keep_alive == 2) {
748                 rctx->keep_alive = 0;
749                 ERR_raise(ERR_LIB_HTTP, HTTP_R_SERVER_CANCELED_CONNECTION);
750                 return 0;
751             }
752             rctx->keep_alive = 0;
753         }
754 
755         if (rctx->state == OHS_ERROR)
756             return 0;
757 
758         if (rctx->expected_ct != NULL && !found_expected_ct) {
759             ERR_raise_data(ERR_LIB_HTTP, HTTP_R_MISSING_CONTENT_TYPE,
760                            "expected=%s", rctx->expected_ct);
761             return 0;
762         }
763         if (rctx->state == OHS_REDIRECT) {
764             /* http status code indicated redirect but there was no Location */
765             ERR_raise(ERR_LIB_HTTP, HTTP_R_MISSING_REDIRECT_LOCATION);
766             return 0;
767         }
768 
769         if (!rctx->expect_asn1) {
770             rctx->state = OHS_STREAM;
771             return 1;
772         }
773 
774         rctx->state = OHS_ASN1_HEADER;
775 
776         /* Fall thru */
777     case OHS_ASN1_HEADER:
778         /*
779          * Now reading ASN1 header: can read at least 2 bytes which is enough
780          * for ASN1 SEQUENCE header and either length field or at least the
781          * length of the length field.
782          */
783         n = BIO_get_mem_data(rctx->mem, &p);
784         if (n < 2)
785             goto next_io;
786 
787         /* Check it is an ASN1 SEQUENCE */
788         if (*p++ != (V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)) {
789             ERR_raise(ERR_LIB_HTTP, HTTP_R_MISSING_ASN1_ENCODING);
790             return 0;
791         }
792 
793         /* Check out length field */
794         if ((*p & 0x80) != 0) {
795             /*
796              * If MSB set on initial length octet we can now always read 6
797              * octets: make sure we have them.
798              */
799             if (n < 6)
800                 goto next_io;
801             n = *p & 0x7F;
802             /* Not NDEF or excessive length */
803             if (n == 0 || (n > 4)) {
804                 ERR_raise(ERR_LIB_HTTP, HTTP_R_ERROR_PARSING_ASN1_LENGTH);
805                 return 0;
806             }
807             p++;
808             resp_len = 0;
809             for (i = 0; i < n; i++) {
810                 resp_len <<= 8;
811                 resp_len |= *p++;
812             }
813             resp_len += n + 2;
814         } else {
815             resp_len = *p + 2;
816         }
817         if (!check_set_resp_len(rctx, resp_len))
818             return 0;
819 
820         rctx->state = OHS_ASN1_CONTENT;
821 
822         /* Fall thru */
823     case OHS_ASN1_CONTENT:
824     default:
825         n = BIO_get_mem_data(rctx->mem, NULL);
826         if (n < 0 || (size_t)n < rctx->resp_len)
827             goto next_io;
828 
829         rctx->state = OHS_ASN1_DONE;
830         return 1;
831     }
832 }
833 
834 int OSSL_HTTP_REQ_CTX_nbio_d2i(OSSL_HTTP_REQ_CTX *rctx,
835                                ASN1_VALUE **pval, const ASN1_ITEM *it)
836 {
837     const unsigned char *p;
838     int rv;
839 
840     *pval = NULL;
841     if ((rv = OSSL_HTTP_REQ_CTX_nbio(rctx)) != 1)
842         return rv;
843     *pval = ASN1_item_d2i(NULL, &p, BIO_get_mem_data(rctx->mem, &p), it);
844     return *pval != NULL;
845 
846 }
847 
848 #ifndef OPENSSL_NO_SOCK
849 
850 /* set up a new connection BIO, to HTTP server or to HTTP(S) proxy if given */
851 static BIO *http_new_bio(const char *server /* optionally includes ":port" */,
852                          const char *server_port /* explicit server port */,
853                          int use_ssl,
854                          const char *proxy /* optionally includes ":port" */,
855                          const char *proxy_port /* explicit proxy port */)
856 {
857     const char *host = server;
858     const char *port = server_port;
859     BIO *cbio;
860 
861     if (!ossl_assert(server != NULL))
862         return NULL;
863 
864     if (proxy != NULL) {
865         host = proxy;
866         port = proxy_port;
867     }
868 
869     if (port == NULL && strchr(host, ':') == NULL)
870         port = use_ssl ? OSSL_HTTPS_PORT : OSSL_HTTP_PORT;
871 
872     cbio = BIO_new_connect(host /* optionally includes ":port" */);
873     if (cbio == NULL)
874         goto end;
875     if (port != NULL)
876         (void)BIO_set_conn_port(cbio, port);
877 
878  end:
879     return cbio;
880 }
881 #endif /* OPENSSL_NO_SOCK */
882 
883 /* Exchange request and response via HTTP on (non-)blocking BIO */
884 BIO *OSSL_HTTP_REQ_CTX_exchange(OSSL_HTTP_REQ_CTX *rctx)
885 {
886     int rv;
887 
888     if (rctx == NULL) {
889         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
890         return NULL;
891     }
892 
893     for (;;) {
894         rv = OSSL_HTTP_REQ_CTX_nbio(rctx);
895         if (rv != -1)
896             break;
897         /* BIO_should_retry was true */
898         /* will not actually wait if rctx->max_time == 0 */
899         if (BIO_wait(rctx->rbio, rctx->max_time, 100 /* milliseconds */) <= 0)
900             return NULL;
901     }
902 
903     if (rv == 0) {
904         if (rctx->redirection_url == NULL) { /* an error occurred */
905             if (rctx->len_to_send > 0)
906                 ERR_raise(ERR_LIB_HTTP, HTTP_R_ERROR_SENDING);
907             else
908                 ERR_raise(ERR_LIB_HTTP, HTTP_R_ERROR_RECEIVING);
909         }
910         return NULL;
911     }
912     return rctx->state == OHS_STREAM ? rctx->rbio : rctx->mem;
913 }
914 
915 int OSSL_HTTP_is_alive(const OSSL_HTTP_REQ_CTX *rctx)
916 {
917     return rctx != NULL && rctx->keep_alive != 0;
918 }
919 
920 /* High-level HTTP API implementation */
921 
922 /* Initiate an HTTP session using bio, else use given server, proxy, etc. */
923 OSSL_HTTP_REQ_CTX *OSSL_HTTP_open(const char *server, const char *port,
924                                   const char *proxy, const char *no_proxy,
925                                   int use_ssl, BIO *bio, BIO *rbio,
926                                   OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
927                                   int buf_size, int overall_timeout)
928 {
929     BIO *cbio; /* == bio if supplied, used as connection BIO if rbio is NULL */
930     OSSL_HTTP_REQ_CTX *rctx = NULL;
931 
932     if (use_ssl && bio_update_fn == NULL) {
933         ERR_raise(ERR_LIB_HTTP, HTTP_R_TLS_NOT_ENABLED);
934         return NULL;
935     }
936     if (rbio != NULL && (bio == NULL || bio_update_fn != NULL)) {
937         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_INVALID_ARGUMENT);
938         return NULL;
939     }
940 
941     if (bio != NULL) {
942         cbio = bio;
943         if (proxy != NULL || no_proxy != NULL) {
944             ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_INVALID_ARGUMENT);
945             return NULL;
946         }
947     } else {
948 #ifndef OPENSSL_NO_SOCK
949         char *proxy_host = NULL, *proxy_port = NULL;
950 
951         if (server == NULL) {
952             ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
953             return NULL;
954         }
955         if (port != NULL && *port == '\0')
956             port = NULL;
957         if (port == NULL && strchr(server, ':') == NULL)
958             port = use_ssl ? OSSL_HTTPS_PORT : OSSL_HTTP_PORT;
959         proxy = OSSL_HTTP_adapt_proxy(proxy, no_proxy, server, use_ssl);
960         if (proxy != NULL
961             && !OSSL_HTTP_parse_url(proxy, NULL /* use_ssl */, NULL /* user */,
962                                     &proxy_host, &proxy_port, NULL /* num */,
963                                     NULL /* path */, NULL, NULL))
964             return NULL;
965         cbio = http_new_bio(server, port, use_ssl, proxy_host, proxy_port);
966         OPENSSL_free(proxy_host);
967         OPENSSL_free(proxy_port);
968         if (cbio == NULL)
969             return NULL;
970 #else
971         ERR_raise(ERR_LIB_HTTP, HTTP_R_SOCK_NOT_SUPPORTED);
972         return NULL;
973 #endif
974     }
975 
976     (void)ERR_set_mark(); /* prepare removing any spurious libssl errors */
977     if (rbio == NULL && BIO_do_connect_retry(cbio, overall_timeout, -1) <= 0) {
978         if (bio == NULL) /* cbio was not provided by caller */
979             BIO_free_all(cbio);
980         goto end;
981     }
982     /* now overall_timeout is guaranteed to be >= 0 */
983 
984     /* adapt in order to fix callback design flaw, see #17088 */
985     /* callback can be used to wrap or prepend TLS session */
986     if (bio_update_fn != NULL) {
987         BIO *orig_bio = cbio;
988 
989         cbio = (*bio_update_fn)(cbio, arg, 1 /* connect */, use_ssl != 0);
990         if (cbio == NULL) {
991             if (bio == NULL) /* cbio was not provided by caller */
992                 BIO_free_all(orig_bio);
993             goto end;
994         }
995     }
996 
997     rctx = http_req_ctx_new(bio == NULL, cbio, rbio != NULL ? rbio : cbio,
998                             bio_update_fn, arg, use_ssl, proxy, server, port,
999                             buf_size, overall_timeout);
1000 
1001  end:
1002     if (rctx != NULL)
1003         /* remove any spurious error queue entries by ssl_add_cert_chain() */
1004         (void)ERR_pop_to_mark();
1005     else
1006         (void)ERR_clear_last_mark();
1007 
1008     return rctx;
1009 }
1010 
1011 int OSSL_HTTP_set1_request(OSSL_HTTP_REQ_CTX *rctx, const char *path,
1012                            const STACK_OF(CONF_VALUE) *headers,
1013                            const char *content_type, BIO *req,
1014                            const char *expected_content_type, int expect_asn1,
1015                            size_t max_resp_len, int timeout, int keep_alive)
1016 {
1017     int use_http_proxy;
1018 
1019     if (rctx == NULL) {
1020         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
1021         return 0;
1022     }
1023     use_http_proxy = rctx->proxy != NULL && !rctx->use_ssl;
1024     if (use_http_proxy && rctx->server == NULL) {
1025         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_INVALID_ARGUMENT);
1026         return 0;
1027     }
1028     rctx->max_resp_len = max_resp_len; /* allows for 0: indefinite */
1029 
1030     return OSSL_HTTP_REQ_CTX_set_request_line(rctx, req != NULL,
1031                                               use_http_proxy ? rctx->server
1032                                               : NULL, rctx->port, path)
1033         && add1_headers(rctx, headers, rctx->server)
1034         && OSSL_HTTP_REQ_CTX_set_expected(rctx, expected_content_type,
1035                                           expect_asn1, timeout, keep_alive)
1036         && set1_content(rctx, content_type, req);
1037 }
1038 
1039 /*-
1040  * Exchange single HTTP request and response according to rctx.
1041  * If rctx->method_POST then use POST, else use GET and ignore content_type.
1042  * The redirection_url output (freed by caller) parameter is used only for GET.
1043  */
1044 BIO *OSSL_HTTP_exchange(OSSL_HTTP_REQ_CTX *rctx, char **redirection_url)
1045 {
1046     BIO *resp;
1047 
1048     if (rctx == NULL) {
1049         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
1050         return NULL;
1051     }
1052 
1053     if (redirection_url != NULL)
1054         *redirection_url = NULL; /* do this beforehand to prevent dbl free */
1055 
1056     resp = OSSL_HTTP_REQ_CTX_exchange(rctx);
1057     if (resp == NULL) {
1058         if (rctx->redirection_url != NULL) {
1059             if (redirection_url == NULL)
1060                 ERR_raise(ERR_LIB_HTTP, HTTP_R_REDIRECTION_NOT_ENABLED);
1061             else
1062                 /* may be NULL if out of memory: */
1063                 *redirection_url = OPENSSL_strdup(rctx->redirection_url);
1064         } else {
1065             char buf[200];
1066             unsigned long err = ERR_peek_error();
1067             int lib = ERR_GET_LIB(err);
1068             int reason = ERR_GET_REASON(err);
1069 
1070             if (lib == ERR_LIB_SSL || lib == ERR_LIB_HTTP
1071                     || (lib == ERR_LIB_BIO && reason == BIO_R_CONNECT_TIMEOUT)
1072                     || (lib == ERR_LIB_BIO && reason == BIO_R_CONNECT_ERROR)
1073 #ifndef OPENSSL_NO_CMP
1074                     || (lib == ERR_LIB_CMP
1075                         && reason == CMP_R_POTENTIALLY_INVALID_CERTIFICATE)
1076 #endif
1077                 ) {
1078                 if (rctx->server != NULL) {
1079                     BIO_snprintf(buf, sizeof(buf), "server=http%s://%s%s%s",
1080                                  rctx->use_ssl ? "s" : "", rctx->server,
1081                                  rctx->port != NULL ? ":" : "",
1082                                  rctx->port != NULL ? rctx->port : "");
1083                     ERR_add_error_data(1, buf);
1084                 }
1085                 if (rctx->proxy != NULL)
1086                     ERR_add_error_data(2, " proxy=", rctx->proxy);
1087                 if (err == 0) {
1088                     BIO_snprintf(buf, sizeof(buf), " peer has disconnected%s",
1089                                  rctx->use_ssl ? " violating the protocol" :
1090                                  ", likely because it requires the use of TLS");
1091                     ERR_add_error_data(1, buf);
1092                 }
1093             }
1094         }
1095     }
1096 
1097     if (resp != NULL && !BIO_up_ref(resp))
1098         resp = NULL;
1099     return resp;
1100 }
1101 
1102 static int redirection_ok(int n_redir, const char *old_url, const char *new_url)
1103 {
1104     if (n_redir >= HTTP_VERSION_MAX_REDIRECTIONS) {
1105         ERR_raise(ERR_LIB_HTTP, HTTP_R_TOO_MANY_REDIRECTIONS);
1106         return 0;
1107     }
1108     if (*new_url == '/') /* redirection to same server => same protocol */
1109         return 1;
1110     if (HAS_PREFIX(old_url, OSSL_HTTPS_NAME":") &&
1111         !HAS_PREFIX(new_url, OSSL_HTTPS_NAME":")) {
1112         ERR_raise(ERR_LIB_HTTP, HTTP_R_REDIRECTION_FROM_HTTPS_TO_HTTP);
1113         return 0;
1114     }
1115     return 1;
1116 }
1117 
1118 /* Get data via HTTP from server at given URL, potentially with redirection */
1119 BIO *OSSL_HTTP_get(const char *url, const char *proxy, const char *no_proxy,
1120                    BIO *bio, BIO *rbio,
1121                    OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
1122                    int buf_size, const STACK_OF(CONF_VALUE) *headers,
1123                    const char *expected_ct, int expect_asn1,
1124                    size_t max_resp_len, int timeout)
1125 {
1126     char *current_url, *redirection_url = NULL;
1127     int n_redirs = 0;
1128     char *host;
1129     char *port;
1130     char *path;
1131     int use_ssl;
1132     OSSL_HTTP_REQ_CTX *rctx = NULL;
1133     BIO *resp = NULL;
1134     time_t max_time = timeout > 0 ? time(NULL) + timeout : 0;
1135 
1136     if (url == NULL) {
1137         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
1138         return NULL;
1139     }
1140     if ((current_url = OPENSSL_strdup(url)) == NULL)
1141         return NULL;
1142 
1143     for (;;) {
1144         if (!OSSL_HTTP_parse_url(current_url, &use_ssl, NULL /* user */, &host,
1145                                  &port, NULL /* port_num */, &path, NULL, NULL))
1146             break;
1147 
1148         rctx = OSSL_HTTP_open(host, port, proxy, no_proxy,
1149                               use_ssl, bio, rbio, bio_update_fn, arg,
1150                               buf_size, timeout);
1151     new_rpath:
1152         if (rctx != NULL) {
1153             if (!OSSL_HTTP_set1_request(rctx, path, headers,
1154                                         NULL /* content_type */,
1155                                         NULL /* req */,
1156                                         expected_ct, expect_asn1, max_resp_len,
1157                                         -1 /* use same max time (timeout) */,
1158                                         0 /* no keep_alive */)) {
1159                 OSSL_HTTP_REQ_CTX_free(rctx);
1160                 rctx = NULL;
1161            } else {
1162                 resp = OSSL_HTTP_exchange(rctx, &redirection_url);
1163            }
1164         }
1165         OPENSSL_free(path);
1166         if (resp == NULL && redirection_url != NULL) {
1167             if (redirection_ok(++n_redirs, current_url, redirection_url)
1168                     && may_still_retry(max_time, &timeout)) {
1169                 (void)BIO_reset(bio);
1170                 OPENSSL_free(current_url);
1171                 current_url = redirection_url;
1172                 if (*redirection_url == '/') { /* redirection to same server */
1173                     path = OPENSSL_strdup(redirection_url);
1174                     if (path == NULL) {
1175                         OPENSSL_free(host);
1176                         OPENSSL_free(port);
1177                         (void)OSSL_HTTP_close(rctx, 1);
1178                         rctx = NULL;
1179                         BIO_free(resp);
1180                         OPENSSL_free(current_url);
1181                         return NULL;
1182                     }
1183                     goto new_rpath;
1184                 }
1185                 OPENSSL_free(host);
1186                 OPENSSL_free(port);
1187                 (void)OSSL_HTTP_close(rctx, 1);
1188                 rctx = NULL;
1189                 continue;
1190             }
1191             /* if redirection not allowed, ignore it */
1192             OPENSSL_free(redirection_url);
1193         }
1194         OPENSSL_free(host);
1195         OPENSSL_free(port);
1196         if (!OSSL_HTTP_close(rctx, resp != NULL)) {
1197             BIO_free(resp);
1198             rctx = NULL;
1199             resp = NULL;
1200         }
1201         break;
1202     }
1203     OPENSSL_free(current_url);
1204     return resp;
1205 }
1206 
1207 /* Exchange request and response over a connection managed via |prctx| */
1208 BIO *OSSL_HTTP_transfer(OSSL_HTTP_REQ_CTX **prctx,
1209                         const char *server, const char *port,
1210                         const char *path, int use_ssl,
1211                         const char *proxy, const char *no_proxy,
1212                         BIO *bio, BIO *rbio,
1213                         OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
1214                         int buf_size, const STACK_OF(CONF_VALUE) *headers,
1215                         const char *content_type, BIO *req,
1216                         const char *expected_ct, int expect_asn1,
1217                         size_t max_resp_len, int timeout, int keep_alive)
1218 {
1219     OSSL_HTTP_REQ_CTX *rctx = prctx == NULL ? NULL : *prctx;
1220     BIO *resp = NULL;
1221 
1222     if (rctx == NULL) {
1223         rctx = OSSL_HTTP_open(server, port, proxy, no_proxy,
1224                               use_ssl, bio, rbio, bio_update_fn, arg,
1225                               buf_size, timeout);
1226         timeout = -1; /* Already set during opening the connection */
1227     }
1228     if (rctx != NULL) {
1229         if (OSSL_HTTP_set1_request(rctx, path, headers, content_type, req,
1230                                    expected_ct, expect_asn1,
1231                                    max_resp_len, timeout, keep_alive))
1232             resp = OSSL_HTTP_exchange(rctx, NULL);
1233         if (resp == NULL || !OSSL_HTTP_is_alive(rctx)) {
1234             if (!OSSL_HTTP_close(rctx, resp != NULL)) {
1235                 BIO_free(resp);
1236                 resp = NULL;
1237             }
1238             rctx = NULL;
1239         }
1240     }
1241     if (prctx != NULL)
1242         *prctx = rctx;
1243     return resp;
1244 }
1245 
1246 int OSSL_HTTP_close(OSSL_HTTP_REQ_CTX *rctx, int ok)
1247 {
1248     BIO *wbio;
1249     int ret = 1;
1250 
1251     /* callback can be used to finish TLS session and free its BIO */
1252     if (rctx != NULL && rctx->upd_fn != NULL) {
1253         wbio = (*rctx->upd_fn)(rctx->wbio, rctx->upd_arg,
1254                                0 /* disconnect */, ok);
1255         ret = wbio != NULL;
1256         if (ret)
1257             rctx->wbio = wbio;
1258     }
1259     OSSL_HTTP_REQ_CTX_free(rctx);
1260     return ret;
1261 }
1262 
1263 /* BASE64 encoder used for encoding basic proxy authentication credentials */
1264 static char *base64encode(const void *buf, size_t len)
1265 {
1266     int i;
1267     size_t outl;
1268     char *out;
1269 
1270     /* Calculate size of encoded data */
1271     outl = (len / 3);
1272     if (len % 3 > 0)
1273         outl++;
1274     outl <<= 2;
1275     out = OPENSSL_malloc(outl + 1);
1276     if (out == NULL)
1277         return 0;
1278 
1279     i = EVP_EncodeBlock((unsigned char *)out, buf, len);
1280     if (!ossl_assert(0 <= i && (size_t)i <= outl)) {
1281         OPENSSL_free(out);
1282         return NULL;
1283     }
1284     return out;
1285 }
1286 
1287 /*
1288  * Promote the given connection BIO using the CONNECT method for a TLS proxy.
1289  * This is typically called by an app, so bio_err and prog are used unless NULL
1290  * to print additional diagnostic information in a user-oriented way.
1291  */
1292 int OSSL_HTTP_proxy_connect(BIO *bio, const char *server, const char *port,
1293                             const char *proxyuser, const char *proxypass,
1294                             int timeout, BIO *bio_err, const char *prog)
1295 {
1296 #undef BUF_SIZE
1297 #define BUF_SIZE (8 * 1024)
1298     char *mbuf = OPENSSL_malloc(BUF_SIZE);
1299     char *mbufp;
1300     int read_len = 0;
1301     int ret = 0;
1302     BIO *fbio = BIO_new(BIO_f_buffer());
1303     int rv;
1304     time_t max_time = timeout > 0 ? time(NULL) + timeout : 0;
1305 
1306     if (bio == NULL || server == NULL
1307             || (bio_err != NULL && prog == NULL)) {
1308         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
1309         goto end;
1310     }
1311     if (port == NULL || *port == '\0')
1312         port = OSSL_HTTPS_PORT;
1313 
1314     if (mbuf == NULL || fbio == NULL) {
1315         BIO_printf(bio_err /* may be NULL */, "%s: out of memory", prog);
1316         goto end;
1317     }
1318     BIO_push(fbio, bio);
1319 
1320     BIO_printf(fbio, "CONNECT %s:%s "HTTP_1_0"\r\n", server, port);
1321 
1322     /*
1323      * Workaround for broken proxies which would otherwise close
1324      * the connection when entering tunnel mode (e.g., Squid 2.6)
1325      */
1326     BIO_printf(fbio, "Proxy-Connection: Keep-Alive\r\n");
1327 
1328     /* Support for basic (base64) proxy authentication */
1329     if (proxyuser != NULL) {
1330         size_t len = strlen(proxyuser) + 1;
1331         char *proxyauth, *proxyauthenc = NULL;
1332 
1333         if (proxypass != NULL)
1334             len += strlen(proxypass);
1335         proxyauth = OPENSSL_malloc(len + 1);
1336         if (proxyauth == NULL)
1337             goto end;
1338         if (BIO_snprintf(proxyauth, len + 1, "%s:%s", proxyuser,
1339                          proxypass != NULL ? proxypass : "") != (int)len)
1340             goto proxy_end;
1341         proxyauthenc = base64encode(proxyauth, len);
1342         if (proxyauthenc != NULL) {
1343             BIO_printf(fbio, "Proxy-Authorization: Basic %s\r\n", proxyauthenc);
1344             OPENSSL_clear_free(proxyauthenc, strlen(proxyauthenc));
1345         }
1346     proxy_end:
1347         OPENSSL_clear_free(proxyauth, len);
1348         if (proxyauthenc == NULL)
1349             goto end;
1350     }
1351 
1352     /* Terminate the HTTP CONNECT request */
1353     BIO_printf(fbio, "\r\n");
1354 
1355     for (;;) {
1356         if (BIO_flush(fbio) != 0)
1357             break;
1358         /* potentially needs to be retried if BIO is non-blocking */
1359         if (!BIO_should_retry(fbio))
1360             break;
1361     }
1362 
1363     for (;;) {
1364         /* will not actually wait if timeout == 0 */
1365         rv = BIO_wait(fbio, max_time, 100 /* milliseconds */);
1366         if (rv <= 0) {
1367             BIO_printf(bio_err, "%s: HTTP CONNECT %s\n", prog,
1368                        rv == 0 ? "timed out" : "failed waiting for data");
1369             goto end;
1370         }
1371 
1372         /*-
1373          * The first line is the HTTP response.
1374          * According to RFC 7230, it is formatted exactly like this:
1375          * HTTP/d.d ddd reason text\r\n
1376          */
1377         read_len = BIO_gets(fbio, mbuf, BUF_SIZE);
1378         /* the BIO may not block, so we must wait for the 1st line to come in */
1379         if (read_len < (int)HTTP_LINE1_MINLEN)
1380             continue;
1381 
1382         /* Check for HTTP/1.x */
1383         if (!HAS_PREFIX(mbuf, HTTP_PREFIX) != 0) {
1384             ERR_raise(ERR_LIB_HTTP, HTTP_R_HEADER_PARSE_ERROR);
1385             BIO_printf(bio_err, "%s: HTTP CONNECT failed, non-HTTP response\n",
1386                        prog);
1387             /* Wrong protocol, not even HTTP, so stop reading headers */
1388             goto end;
1389         }
1390         mbufp = mbuf + strlen(HTTP_PREFIX);
1391         if (!HAS_PREFIX(mbufp, HTTP_VERSION_PATT) != 0) {
1392             ERR_raise(ERR_LIB_HTTP, HTTP_R_RECEIVED_WRONG_HTTP_VERSION);
1393             BIO_printf(bio_err,
1394                        "%s: HTTP CONNECT failed, bad HTTP version %.*s\n",
1395                        prog, (int)HTTP_VERSION_STR_LEN, mbufp);
1396             goto end;
1397         }
1398         mbufp += HTTP_VERSION_STR_LEN;
1399 
1400         /* RFC 7231 4.3.6: any 2xx status code is valid */
1401         if (!HAS_PREFIX(mbufp, " 2")) {
1402             /* chop any trailing whitespace */
1403             while (read_len > 0 && ossl_isspace(mbuf[read_len - 1]))
1404                 read_len--;
1405             mbuf[read_len] = '\0';
1406             ERR_raise_data(ERR_LIB_HTTP, HTTP_R_CONNECT_FAILURE,
1407                            "reason=%s", mbufp);
1408             BIO_printf(bio_err, "%s: HTTP CONNECT failed, reason=%s\n",
1409                        prog, mbufp);
1410             goto end;
1411         }
1412         ret = 1;
1413         break;
1414     }
1415 
1416     /* Read past all following headers */
1417     do {
1418         /*
1419          * This does not necessarily catch the case when the full
1420          * HTTP response came in in more than a single TCP message.
1421          */
1422         read_len = BIO_gets(fbio, mbuf, BUF_SIZE);
1423     } while (read_len > 2);
1424 
1425  end:
1426     if (fbio != NULL) {
1427         (void)BIO_flush(fbio);
1428         BIO_pop(fbio);
1429         BIO_free(fbio);
1430     }
1431     OPENSSL_free(mbuf);
1432     return ret;
1433 #undef BUF_SIZE
1434 }
1435