Generalize the HTTP client so far implemented mostly in crypto/ocsp/ocsp_ht.c

The new client has become an independent libcrpyto module in crypto/http/ and
* can handle any types of requests and responses (ASN.1-encoded and plain)
* does not include potentially busy loops when waiting for responses but
* makes use of a new timeout mechanism integrated with socket-based BIO
* supports the use of HTTP proxies and TLS, including HTTPS over proxies
* supports HTTP redirection via codes 301 and 302 for GET requests
* returns more useful diagnostics in various error situations
Also adapts - and strongly simplifies - hitherto uses of HTTP in crypto/ocsp/,
crypto/x509/x_all.c, apps/lib/apps.c, and apps/{ocsp,s_client,s_server}.c

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/10667)

5 files changed, 1474 insertions, 0 deletions

diff --git a/crypto/http/build.info b/crypto/http/build.info
new file mode 100644
index 0000000000..b4626b13de
--- /dev/null
+++ b/crypto/http/build.info
@@ -0,0 +1,2 @@
+LIBS=../../libcrypto
+SOURCE[../../libcrypto]=http_client.c http_err.c http_lib.c
diff --git a/crypto/http/http_client.c b/crypto/http/http_client.c
new file mode 100644
index 0000000000..424b4c3922
--- /dev/null
+++ b/crypto/http/http_client.c
@@ -0,0 +1,1238 @@
+/*
+ * Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright Siemens AG 2018-2020
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include "e_os.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "crypto/ctype.h"
+#include <string.h>
+#include <openssl/asn1.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include <openssl/httperr.h>
+#include <openssl/cmperr.h>
+#include <openssl/buffer.h>
+#include <openssl/http.h>
+#include "internal/sockets.h"
+#include "internal/cryptlib.h"
+
+#include "http_local.h"
+
+#define HTTP_PREFIX "HTTP/"
+#define HTTP_VERSION_PATT "1." /* allow 1.x */
+#define HTTP_VERSION_STR_LEN 3
+#define HTTP_LINE1_MINLEN ((int)strlen(HTTP_PREFIX HTTP_VERSION_PATT "x 200\n"))
+#define HTTP_VERSION_MAX_REDIRECTIONS 50
+
+#define HTTP_STATUS_CODE_OK                200
+#define HTTP_STATUS_CODE_MOVED_PERMANENTLY 301
+#define HTTP_STATUS_CODE_FOUND             302
+
+
+/* Stateful HTTP request code, supporting blocking and non-blocking I/O */
+
+/* Opaque HTTP request status structure */
+
+struct ossl_http_req_ctx_st {
+    int state;                  /* Current I/O state */
+    unsigned char *iobuf;       /* Line buffer */
+    int iobuflen;               /* Line buffer length */
+    BIO *wbio;                  /* BIO to send request to */
+    BIO *rbio;                  /* BIO to read response from */
+    BIO *mem;                   /* Memory BIO response is built into */
+    int method_GET;             /* HTTP method "GET" or "POST" */
+    const char *expected_ct;    /* expected Content-Type, or NULL */
+    int expect_asn1;            /* response must be ASN.1-encoded */
+    unsigned long resp_len;     /* length of response */
+    unsigned long max_resp_len; /* Maximum length of response */
+    time_t max_time;            /* Maximum end time of the transfer, or 0 */
+    char *redirection_url;      /* Location given with HTTP status 301/302 */
+};
+
+#define HTTP_DEFAULT_MAX_LINE_LENGTH (4 * 1024)
+#define HTTP_DEFAULT_MAX_RESP_LEN (100 * 1024)
+
+/* HTTP states */
+
+#define OHS_NOREAD          0x1000 /* If set no reading should be performed */
+#define OHS_ERROR           (0 | OHS_NOREAD) /* Error condition */
+#define OHS_FIRSTLINE       1 /* First line being read */
+#define OHS_REDIRECT        0xa /* Looking for redirection location */
+#define OHS_HEADERS         2 /* MIME headers being read */
+#define OHS_ASN1_HEADER     3 /* HTTP initial header (tag+length) being read */
+#define OHS_CONTENT         4 /* HTTP content octets being read */
+#define OHS_WRITE_INIT     (5 | OHS_NOREAD) /* 1st call: ready to start I/O */
+#define OHS_WRITE          (6 | OHS_NOREAD) /* Request being sent */
+#define OHS_FLUSH          (7 | OHS_NOREAD) /* Request being flushed */
+#define OHS_DONE           (8 | OHS_NOREAD) /* Completed */
+#define OHS_HTTP_HEADER    (9 | OHS_NOREAD) /* Headers set, w/o final \r\n */
+
+OSSL_HTTP_REQ_CTX *OSSL_HTTP_REQ_CTX_new(BIO *wbio, BIO *rbio,
+                                         int method_GET, int maxline,
+                                         unsigned long max_resp_len,
+                                         int timeout,
+                                         const char *expected_content_type,
+                                         int expect_asn1)
+{
+    OSSL_HTTP_REQ_CTX *rctx;
+
+    if (wbio == NULL || rbio == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+
+    if ((rctx = OPENSSL_zalloc(sizeof(*rctx))) == NULL)
+        return NULL;
+    rctx->state = OHS_ERROR;
+    rctx->iobuflen = maxline > 0 ? maxline : HTTP_DEFAULT_MAX_LINE_LENGTH;
+    rctx->iobuf = OPENSSL_malloc(rctx->iobuflen);
+    rctx->wbio = wbio;
+    rctx->rbio = rbio;
+    rctx->mem = BIO_new(BIO_s_mem());
+    if (rctx->iobuf == NULL || rctx->mem == NULL) {
+        OSSL_HTTP_REQ_CTX_free(rctx);
+        return NULL;
+    }
+    rctx->method_GET = method_GET;
+    rctx->expected_ct = expected_content_type;
+    rctx->expect_asn1 = expect_asn1;
+    rctx->resp_len = 0;
+    OSSL_HTTP_REQ_CTX_set_max_response_length(rctx, max_resp_len);
+    rctx->max_time = timeout > 0 ? time(NULL) + timeout : 0;
+    return rctx;
+}
+
+void OSSL_HTTP_REQ_CTX_free(OSSL_HTTP_REQ_CTX *rctx)
+{
+    if (rctx == NULL)
+        return;
+    BIO_free(rctx->mem); /* this may indirectly call ERR_clear_error() */
+    OPENSSL_free(rctx->iobuf);
+    OPENSSL_free(rctx);
+}
+
+BIO *OSSL_HTTP_REQ_CTX_get0_mem_bio(OSSL_HTTP_REQ_CTX *rctx)
+{
+    if (rctx == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+    return rctx->mem;
+}
+
+void OSSL_HTTP_REQ_CTX_set_max_response_length(OSSL_HTTP_REQ_CTX *rctx,
+                                               unsigned long len)
+{
+    if (rctx == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return;
+    }
+    rctx->max_resp_len = len != 0 ? len : HTTP_DEFAULT_MAX_RESP_LEN;
+}
+
+/*
+ * Create HTTP header using given op and path (or "/" in case path is NULL).
+ * Server name (and port) must be given if and only if plain HTTP proxy is used.
+ */
+int OSSL_HTTP_REQ_CTX_header(OSSL_HTTP_REQ_CTX *rctx, const char *server,
+                             const char *port, const char *path)
+{
+    if (rctx == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    if (BIO_printf(rctx->mem, "%s ", rctx->method_GET ? "GET" : "POST") <= 0)
+        return 0;
+
+    if (server != NULL) { /* HTTP (but not HTTPS) proxy is used */
+        /*
+         * Section 5.1.2 of RFC 1945 states that the absoluteURI form is only
+         * allowed when using a proxy
+         */
+        if (BIO_printf(rctx->mem, "http://%s", server) <= 0)
+            return 0;
+        if (port != NULL && BIO_printf(rctx->mem, ":%s", port) <= 0)
+            return 0;
+    }
+
+    /* Make sure path includes a forward slash */
+    if (path == NULL)
+        path = "/";
+    if (path[0] != '/' && BIO_printf(rctx->mem, "/") <= 0)
+        return 0;
+
+    if (BIO_printf(rctx->mem, "%s "HTTP_PREFIX"1.0\r\n", path) <= 0)
+        return 0;
+    rctx->state = OHS_HTTP_HEADER;
+    return 1;
+}
+
+int OSSL_HTTP_REQ_CTX_add1_header(OSSL_HTTP_REQ_CTX *rctx,
+                                  const char *name, const char *value)
+{
+    if (rctx == NULL || name == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    if (BIO_puts(rctx->mem, name) <= 0)
+        return 0;
+    if (value != NULL) {
+        if (BIO_write(rctx->mem, ": ", 2) != 2)
+            return 0;
+        if (BIO_puts(rctx->mem, value) <= 0)
+            return 0;
+    }
+    if (BIO_write(rctx->mem, "\r\n", 2) != 2)
+        return 0;
+    rctx->state = OHS_HTTP_HEADER;
+    return 1;
+}
+
+static int OSSL_HTTP_REQ_CTX_content(OSSL_HTTP_REQ_CTX *rctx,
+                                     const char *content_type, BIO *req_mem)
+{
+    const unsigned char *req;
+    long req_len;
+
+    if (rctx == NULL || req_mem == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    if (content_type != NULL
+            && BIO_printf(rctx->mem, "Content-Type: %s\r\n", content_type) <= 0)
+        return 0;
+
+    if ((req_len = BIO_get_mem_data(req_mem, &req)) <= 0)
+        return 0;
+    rctx->state = OHS_WRITE_INIT;
+
+    return BIO_printf(rctx->mem, "Content-Length: %ld\r\n\r\n", req_len) > 0
+        && BIO_write(rctx->mem, req, req_len) == (int)req_len;
+}
+
+BIO *HTTP_asn1_item2bio(const ASN1_ITEM *it, ASN1_VALUE *val)
+{
+    BIO *res;
+
+    if (it == NULL || val == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+
+    if ((res = BIO_new(BIO_s_mem())) == NULL)
+        return NULL;
+    if (ASN1_item_i2d_bio(it, res, val) <= 0) {
+        BIO_free(res);
+        res = NULL;
+    }
+    return res;
+}
+
+int OSSL_HTTP_REQ_CTX_i2d(OSSL_HTTP_REQ_CTX *rctx, const char *content_type,
+                          const ASN1_ITEM *it, ASN1_VALUE *req)
+{
+    BIO *mem;
+    int res;
+
+    if (rctx == NULL || it == NULL || req == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    res = (mem = HTTP_asn1_item2bio(it, req)) != NULL
+        && OSSL_HTTP_REQ_CTX_content(rctx, content_type, mem);
+    BIO_free(mem);
+    return res;
+}
+
+static int OSSL_HTTP_REQ_CTX_add1_headers(OSSL_HTTP_REQ_CTX *rctx,
+                                          const STACK_OF(CONF_VALUE) *headers,
+                                          const char *host)
+{
+    int i;
+    int add_host = 1;
+    CONF_VALUE *hdr;
+
+    for (i = 0; i < sk_CONF_VALUE_num(headers); i++) {
+        hdr = sk_CONF_VALUE_value(headers, i);
+        if (add_host && strcasecmp("host", hdr->name) == 0)
+            add_host = 0;
+        if (!OSSL_HTTP_REQ_CTX_add1_header(rctx, hdr->name, hdr->value))
+            return 0;
+    }
+
+    if (add_host && !OSSL_HTTP_REQ_CTX_add1_header(rctx, "Host", host))
+        return 0;
+    return 1;
+}
+
+/*-
+ * Create OSSL_HTTP_REQ_CTX structure using the values provided.
+ * If !use_http_proxy then the 'server' and 'port' parameters are ignored.
+ * If req_mem == NULL then use GET and ignore content_type, else POST.
+ */
+OSSL_HTTP_REQ_CTX *HTTP_REQ_CTX_new(BIO *wbio, BIO *rbio, int use_http_proxy,
+                                    const char *server, const char *port,
+                                    const char *path,
+                                    const STACK_OF(CONF_VALUE) *headers,
+                                    const char *content_type, BIO *req_mem,
+                                    int maxline, unsigned long max_resp_len,
+                                    int timeout,
+                                    const char *expected_content_type,
+                                    int expect_asn1)
+{
+    OSSL_HTTP_REQ_CTX *rctx;
+
+    if (use_http_proxy && (server == NULL || port == NULL)) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+    /* remaining parameters are checked indirectly by the functions called */
+
+    if ((rctx = OSSL_HTTP_REQ_CTX_new(wbio, rbio, req_mem == NULL, maxline,
+                                      max_resp_len, timeout,
+                                      expected_content_type, expect_asn1))
+        == NULL)
+        return NULL;
+
+    if (OSSL_HTTP_REQ_CTX_header(rctx, use_http_proxy ? server : NULL,
+                                 port, path)
+        && OSSL_HTTP_REQ_CTX_add1_headers(rctx, headers, server)
+        && (req_mem == NULL
+            || OSSL_HTTP_REQ_CTX_content(rctx, content_type, req_mem)))
+        return rctx;
+
+    OSSL_HTTP_REQ_CTX_free(rctx);
+    return NULL;
+}
+
+/*
+ * Parse first HTTP response line. This should be like this: "HTTP/1.0 200 OK".
+ * We need to obtain the numeric code and (optional) informational message.
+ */
+
+static int parse_http_line1(char *line)
+{
+    int retcode;
+    char *code, *reason, *end;
+
+    /* Skip to first whitespace (past protocol info) */
+    for (code = line; *code != '\0' && !ossl_isspace(*code); code++)
+        continue;
+    if (*code == '\0') {
+        HTTPerr(0, HTTP_R_SERVER_RESPONSE_PARSE_ERROR);
+        return 0;
+    }
+
+    /* Skip past whitespace to start of response code */
+    while (*code != '\0' && ossl_isspace(*code))
+        code++;
+
+    if (*code == '\0') {
+        HTTPerr(0, HTTP_R_SERVER_RESPONSE_PARSE_ERROR);
+        return 0;
+    }
+
+    /* Find end of response code: first whitespace after start of code */
+    for (reason = code; *reason != '\0' && !ossl_isspace(*reason); reason++)
+        continue;
+
+    if (*reason == '\0') {
+        HTTPerr(0, HTTP_R_SERVER_RESPONSE_PARSE_ERROR);
+        return 0;
+    }
+
+    /* Set end of response code and start of message */
+    *reason++ = '\0';
+
+    /* Attempt to parse numeric code */
+    retcode = strtoul(code, &end, 10);
+
+    if (*end != '\0')
+        return 0;
+
+    /* Skip over any leading whitespace in message */
+    while (*reason != '\0' && ossl_isspace(*reason))
+        reason++;
+
+    if (*reason != '\0') {
+        /*
+         * Finally zap any trailing whitespace in message (include CRLF)
+         */
+
+        /* chop any trailing whitespace from reason */
+        /* We know reason has a non-whitespace character so this is OK */
+        for (end = reason + strlen(reason) - 1; ossl_isspace(*end); end--)
+            *end = '\0';
+    }
+
+    switch (retcode) {
+    case HTTP_STATUS_CODE_OK:
+    case HTTP_STATUS_CODE_MOVED_PERMANENTLY:
+    case HTTP_STATUS_CODE_FOUND:
+        return retcode;
+    default:
+        if (retcode < 400)
+            HTTPerr(0, HTTP_R_STATUS_CODE_UNSUPPORTED);
+        else
+            HTTPerr(0, HTTP_R_SERVER_SENT_ERROR);
+        if (*reason == '\0')
+            ERR_add_error_data(2, "Code=", code);
+        else
+            ERR_add_error_data(4, "Code=", code, ",Reason=", reason);
+        return 0;
+    }
+}
+
+static int check_set_resp_len(OSSL_HTTP_REQ_CTX *rctx, unsigned long len)
+{
+    const char *tag = NULL;
+    unsigned long val = 0;
+
+    if (len > rctx->max_resp_len) {
+        HTTPerr(0, HTTP_R_MAX_RESP_LEN_EXCEEDED);
+        tag = ",max=";
+        val = rctx->max_resp_len;
+    }
+    if (rctx->resp_len != 0 && rctx->resp_len != len) {
+        HTTPerr(0, HTTP_R_INCONSISTENT_CONTENT_LENGTH);
+        tag = ",before=";
+        val = rctx->resp_len;
+    }
+    if (tag != NULL) {
+        char len_str[32];
+        char str[32];
+
+        BIO_snprintf(len_str, sizeof(len_str), "%lu", len);
+        BIO_snprintf(str, sizeof(str), "%lu", val);
+        ERR_add_error_data(4, "length=", len_str, tag, str);
+        return 0;
+    }
+    rctx->resp_len = len;
+    return 1;
+}
+
+/*
+ * Try exchanging request and response via HTTP on (non-)blocking BIO in rctx.
+ * Returns 1 on success, 0 on error or redirection, -1 on BIO_should_retry.
+ */
+int OSSL_HTTP_REQ_CTX_nbio(OSSL_HTTP_REQ_CTX *rctx)
+{
+    int i;
+    long n, n_to_send = 0;
+    unsigned long resp_len;
+    const unsigned char *p;
+    char *key, *value, *line_end = NULL;
+
+    if (rctx == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    rctx->redirection_url = NULL;
+ next_io:
+    if ((rctx->state & OHS_NOREAD) == 0) {
+        n = BIO_read(rctx->rbio, rctx->iobuf, rctx->iobuflen);
+        if (n <= 0) {
+            if (BIO_should_retry(rctx->rbio))
+                return -1;
+            return 0;
+        }
+
+        /* Write data to memory BIO */
+        if (BIO_write(rctx->mem, rctx->iobuf, n) != n)
+            return 0;
+    }
+
+    switch (rctx->state) {
+    case OHS_HTTP_HEADER:
+        /* Last operation was adding headers: need a final \r\n */
+        if (BIO_write(rctx->mem, "\r\n", 2) != 2) {
+            rctx->state = OHS_ERROR;
+            return 0;
+        }
+        rctx->state = OHS_WRITE_INIT;
+
+        /* fall thru */
+    case OHS_WRITE_INIT:
+        n_to_send = BIO_get_mem_data(rctx->mem, NULL);
+        rctx->state = OHS_WRITE;
+
+        /* fall thru */
+    case OHS_WRITE:
+        n = BIO_get_mem_data(rctx->mem, &p);
+
+        i = BIO_write(rctx->wbio, p + (n - n_to_send), n_to_send);
+
+        if (i <= 0) {
+            if (BIO_should_retry(rctx->wbio))
+                return -1;
+            rctx->state = OHS_ERROR;
+            return 0;
+        }
+
+        n_to_send -= i;
+
+        if (n_to_send > 0)
+            goto next_io;
+
+        rctx->state = OHS_FLUSH;
+
+        (void)BIO_reset(rctx->mem);
+
+        /* fall thru */
+    case OHS_FLUSH:
+
+        i = BIO_flush(rctx->wbio);
+
+        if (i > 0) {
+            rctx->state = OHS_FIRSTLINE;
+            goto next_io;
+        }
+
+        if (BIO_should_retry(rctx->wbio))
+            return -1;
+
+        rctx->state = OHS_ERROR;
+        return 0;
+
+    case OHS_ERROR:
+        return 0;
+
+    case OHS_FIRSTLINE:
+    case OHS_HEADERS:
+    case OHS_REDIRECT:
+
+        /* Attempt to read a line in */
+ next_line:
+        /*
+         * Due to strange memory BIO behavior with BIO_gets we have to check
+         * there's a complete line in there before calling BIO_gets or we'll
+         * just get a partial read.
+         */
+        n = BIO_get_mem_data(rctx->mem, &p);
+        if (n <= 0 || memchr(p, '\n', n) == 0) {
+            if (n >= rctx->iobuflen) {
+                rctx->state = OHS_ERROR;
+                return 0;
+            }
+            goto next_io;
+        }
+        n = BIO_gets(rctx->mem, (char *)rctx->iobuf, rctx->iobuflen);
+
+        if (n <= 0) {
+            if (BIO_should_retry(rctx->mem))
+                goto next_io;
+            rctx->state = OHS_ERROR;
+            return 0;
+        }
+
+        /* Don't allow excessive lines */
+        if (n == rctx->iobuflen) {
+            HTTPerr(0, HTTP_R_RESPONSE_LINE_TOO_LONG);
+            rctx->state = OHS_ERROR;
+            return 0;
+        }
+
+        /* First line */
+        if (rctx->state == OHS_FIRSTLINE) {
+            switch (parse_http_line1((char *)rctx->iobuf)) {
+            case HTTP_STATUS_CODE_OK:
+                rctx->state = OHS_HEADERS;
+                goto next_line;
+            case HTTP_STATUS_CODE_MOVED_PERMANENTLY:
+            case HTTP_STATUS_CODE_FOUND: /* i.e., moved temporarily */
+                if (rctx->method_GET) {
+                    rctx->state = OHS_REDIRECT;
+                    goto next_line;
+                }
+                HTTPerr(0, HTTP_R_REDIRECTION_NOT_ENABLED);
+                /* redirection is not supported/recommended for POST */
+                /* fall through */
+            default:
+                rctx->state = OHS_ERROR;
+                return 0;
+            }
+        }
+        key = (char *)rctx->iobuf;
+        value = strchr(key, ':');
+        if (value != NULL) {
+            *(value++) = '\0';
+            while (ossl_isspace(*value))
+                value++;
+            line_end = strchr(value, '\r');
+            if (line_end == NULL)
+                line_end = strchr(value, '\n');
+            if (line_end != NULL)
+                *line_end = '\0';
+        }
+        if (value != NULL && line_end != NULL) {
+            if (rctx->state == OHS_REDIRECT && strcmp(key, "Location") == 0) {
+                rctx->redirection_url = value;
+                return 0;
+            }
+            if (rctx->expected_ct != NULL && strcmp(key, "Content-Type") == 0) {
+                if (strcmp(rctx->expected_ct, value) != 0) {
+                    HTTPerr(0, HTTP_R_UNEXPECTED_CONTENT_TYPE);
+                    ERR_add_error_data(4, "expected=", rctx->expected_ct,
+                                       ",actual=", value);
+                    return 0;
+                }
+                rctx->expected_ct = NULL; /* content-type has been found */
+            }
+            if (strcmp(key, "Content-Length") == 0) {
+                resp_len = strtoul(value, &line_end, 10);
+                if (line_end == value || *line_end != '\0') {
+                    HTTPerr(0, HTTP_R_ERROR_PARSING_CONTENT_LENGTH);
+                    ERR_add_error_data(2, "input=", value);
+                    return 0;
+                }
+                if (!check_set_resp_len(rctx, resp_len))
+                    return 0;
+            }
+        }
+
+        /* Look for blank line: end of headers */
+        for (p = rctx->iobuf; *p != '\0' ; p++) {
+            if (*p != '\r' && *p != '\n')
+                break;
+        }
+        if (*p != '\0') /* not end of headers */
+            goto next_line;
+
+        if (rctx->expected_ct != NULL) {
+            HTTPerr(0, HTTP_R_MISSING_CONTENT_TYPE);
+            ERR_add_error_data(2, "expected=", rctx->expected_ct);
+            return 0;
+        }
+        if (rctx->state == OHS_REDIRECT) {
+            /* http status code indicated redirect but there was no Location */
+            HTTPerr(0, HTTP_R_MISSING_REDIRECT_LOCATION);
+            return 0;
+        }
+
+        if (!rctx->expect_asn1) {
+            rctx->state = OHS_CONTENT;
+            goto content;
+        }
+
+        rctx->state = OHS_ASN1_HEADER;
+
+        /* Fall thru */
+    case OHS_ASN1_HEADER:
+        /*
+         * Now reading ASN1 header: can read at least 2 bytes which is enough
+         * for ASN1 SEQUENCE header and either length field or at least the
+         * length of the length field.
+         */
+        n = BIO_get_mem_data(rctx->mem, &p);
+        if (n < 2)
+            goto next_io;
+
+        /* Check it is an ASN1 SEQUENCE */
+        if (*p++ != (V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)) {
+            HTTPerr(0, HTTP_R_MISSING_ASN1_ENCODING);
+            return 0;
+        }
+
+        /* Check out length field */
+        if ((*p & 0x80) != 0) {
+            /*
+             * If MSB set on initial length octet we can now always read 6
+             * octets: make sure we have them.
+             */
+            if (n < 6)
+                goto next_io;
+            n = *p & 0x7F;
+            /* Not NDEF or excessive length */
+            if (n == 0 || (n > 4)) {
+                HTTPerr(0, HTTP_R_ERROR_PARSING_ASN1_LENGTH);
+                return 0;
+            }
+            p++;
+            resp_len = 0;
+            for (i = 0; i < n; i++) {
+                resp_len <<= 8;
+                resp_len |= *p++;
+            }
+            resp_len += n + 2;
+        } else {
+            resp_len = *p + 2;
+        }
+        if (!check_set_resp_len(rctx, resp_len))
+            return 0;
+
+ content:
+        rctx->state = OHS_CONTENT;
+
+        /* Fall thru */
+    case OHS_CONTENT:
+    default:
+        n = BIO_get_mem_data(rctx->mem, NULL);
+        if (n < (long)rctx->resp_len /* may be 0 if no Content-Type or ASN.1 */)
+            goto next_io;
+
+        rctx->state = OHS_DONE;
+        return 1;
+    }
+}
+
+#ifndef OPENSSL_NO_SOCK
+
+/* set up a new connection BIO, to HTTP server or to HTTP(S) proxy if given */
+static BIO *HTTP_new_bio(const char *server, const char *server_port,
+                         const char *proxy, const char *proxy_port)
+{
+    const char *host = server;
+    const char *port = server_port;
+    BIO *cbio;
+
+    if (server == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+
+    if (proxy != NULL) {
+        host = proxy;
+        port = proxy_port;
+    }
+    cbio = BIO_new_connect(host);
+    if (cbio == NULL)
+        goto end;
+    if (port != NULL)
+        (void)BIO_set_conn_port(cbio, port);
+
+ end:
+    return cbio;
+}
+
+static ASN1_VALUE *BIO_mem_d2i(BIO *mem, const ASN1_ITEM *it)
+{
+    const unsigned char *p;
+    long len = BIO_get_mem_data(mem, &p);
+    ASN1_VALUE *resp = ASN1_item_d2i(NULL, &p, len, it);
+
+    if (resp == NULL)
+        HTTPerr(0, HTTP_R_SERVER_RESPONSE_PARSE_ERROR);
+    return resp;
+}
+
+static BIO *OSSL_HTTP_REQ_CTX_transfer(OSSL_HTTP_REQ_CTX *rctx)
+{
+    int sending = 1;
+    int rv;
+
+    if (rctx == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+
+    for (;;) {
+        rv = OSSL_HTTP_REQ_CTX_nbio(rctx);
+        if (rv != -1)
+            break;
+        /* BIO_should_retry was true */
+        sending = 0;
+        /* will not actually wait if rctx->max_time == 0 */
+        if (BIO_wait(rctx->rbio, rctx->max_time) <= 0)
+            return NULL;
+    }
+
+    if (rv == 0) {
+        if (rctx->redirection_url == NULL) { /* an error occurred */
+            if (sending && (rctx->state & OHS_NOREAD) != 0)
+                HTTPerr(0, HTTP_R_ERROR_SENDING);
+            else
+                HTTPerr(0, HTTP_R_ERROR_RECEIVING);
+        }
+        return NULL;
+    }
+    if (!BIO_up_ref(rctx->mem))
+        return NULL;
+    return rctx->mem;
+}
+
+/* Exchange ASN.1-encoded request and response via HTTP on (non-)blocking BIO */
+ASN1_VALUE *OSSL_HTTP_REQ_CTX_sendreq_d2i(OSSL_HTTP_REQ_CTX *rctx,
+                                          const ASN1_ITEM *it)
+{
+    if (rctx == NULL || it == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+    return BIO_mem_d2i(OSSL_HTTP_REQ_CTX_transfer(rctx), it);
+}
+
+static int update_timeout(int timeout, time_t start_time)
+{
+    long elapsed_time;
+
+    if (timeout == 0)
+        return 0;
+    elapsed_time = (long)(time(NULL) - start_time); /* this might overflow */
+    return timeout <= elapsed_time ? -1 : timeout - elapsed_time;
+}
+
+/*-
+ * Exchange HTTP request and response with the given server.
+ * If req_mem == NULL then use GET and ignore content_type, else POST.
+ * The redirection_url output (freed by caller) parameter is used only for GET.
+ *
+ * Typically the bio and rbio parameters are NULL and a network BIO is created
+ * internally for connecting to the given server and port, optionally via a
+ * proxy and its port, and is then used for exchanging the request and response.
+ * If bio is given and rbio is NULL then this BIO is used instead.
+ * If both bio and rbio are given (which may be memory BIOs for instance)
+ * then no explicit connection is attempted,
+ * bio is used for writing the request, and rbio for reading the response.
+ *
+ * bio_update_fn is an optional BIO connect/disconnect callback function,
+ * which has the prototype
+ *   BIO *(*OSSL_HTTP_bio_cb_t) (BIO *bio, void *arg, int conn, int detail);
+ * The callback may modify the HTTP BIO provided in the bio argument,
+ * whereby it may make use of any custom defined argument 'arg'.
+ * During connection establishment, just after BIO_connect_retry(),
+ * the callback function is invoked with the 'conn' argument being 1
+ * 'detail' indicating whether a HTTPS (i.e., TLS) connection is requested.
+ * On disconnect 'conn' is 0 and 'detail' indicates that no error occurred.
+ * For instance, on connect the funct may prepend a TLS BIO to implement HTTPS;
+ * after disconnect it may do some error diagnostics and/or specific cleanup.
+ * The function should return NULL to indicate failure.
+ * After disconnect the modified BIO will be deallocated using BIO_free_all().
+ */
+BIO *OSSL_HTTP_transfer(const char *server, const char *port, const char *path,
+                        int use_ssl, const char *proxy, const char *proxy_port,
+                        BIO *bio, BIO *rbio,
+                        OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
+                        const STACK_OF(CONF_VALUE) *headers,
+                        const char *content_type, BIO *req_mem,
+                        int maxline, unsigned long max_resp_len, int timeout,
+                        const char *expected_ct, int expect_asn1,
+                        char **redirection_url)
+{
+    time_t start_time = timeout > 0 ? time(NULL) : 0;
+    BIO *cbio; /* = bio if present, used as connection BIO if rbio is NULL */
+    OSSL_HTTP_REQ_CTX *rctx;
+    BIO *resp = NULL;
+
+    if (redirection_url != NULL)
+        *redirection_url = NULL; /* do this beforehand to prevent dbl free */
+
+    if (use_ssl && bio_update_fn == NULL) {
+        HTTPerr(0, HTTP_R_TLS_NOT_ENABLED);
+        return NULL;
+    }
+    if (rbio != NULL && (bio == NULL || bio_update_fn != NULL)) {
+        HTTPerr(0, ERR_R_PASSED_INVALID_ARGUMENT);
+        return NULL;
+    }
+    /* remaining parameters are checked indirectly by the functions called */
+
+    if (bio != NULL)
+        cbio = bio;
+    else if ((cbio = HTTP_new_bio(server, port, proxy, proxy_port)) == NULL)
+        return NULL;
+
+    (void)ERR_set_mark(); /* prepare removing any spurious libssl errors */
+    if (rbio == NULL && BIO_connect_retry(cbio, timeout) <= 0)
+        goto end;
+    /* now timeout is guaranteed to be >= 0 */
+
+    /* callback can be used to wrap or prepend TLS session */
+    if (bio_update_fn != NULL) {
+        BIO *orig_bio = cbio;
+        cbio = (*bio_update_fn)(cbio, arg, 1 /* connect */, use_ssl);
+        if (cbio == NULL) {
+            cbio = orig_bio;
+            goto end;
+        }
+    }
+
+    rctx = HTTP_REQ_CTX_new(cbio, rbio != NULL ? rbio : cbio,
+                            !use_ssl && proxy != NULL, server, port, path,
+                            headers, content_type, req_mem, maxline,
+                            max_resp_len, update_timeout(timeout, start_time),
+                            expected_ct, expect_asn1);
+    if (rctx == NULL)
+        goto end;
+
+    resp = OSSL_HTTP_REQ_CTX_transfer(rctx);
+    if (resp == NULL) {
+        if (rctx->redirection_url != NULL) {
+            if (redirection_url == NULL)
+                HTTPerr(0, HTTP_R_REDIRECTION_NOT_ENABLED);
+            else
+                /* may be NULL if out of memory: */
+                *redirection_url = OPENSSL_strdup(rctx->redirection_url);
+        } else {
+            char buf[200];
+            unsigned long err = ERR_peek_error();
+            int lib = ERR_GET_LIB(err);
+            int reason = ERR_GET_REASON(err);
+
+            if (lib == ERR_LIB_SSL || lib == ERR_LIB_HTTP
+                    || (lib == ERR_LIB_BIO && reason == BIO_R_CONNECT_TIMEOUT)
+                    || (lib == ERR_LIB_BIO && reason == BIO_R_CONNECT_ERROR)
+                    || (lib == ERR_LIB_CMP
+                        && reason == CMP_R_POTENTIALLY_INVALID_CERTIFICATE)) {
+                BIO_snprintf(buf, 200, "server=%s:%s", server, port);
+                ERR_add_error_data(1, buf);
+                if (err == 0) {
+                    BIO_snprintf(buf, 200, "server has disconnected%s",
+                                 use_ssl ? " violating the protocol" :
+                                 ", likely because it requires the use of TLS");
+                    ERR_add_error_data(1, buf);
+                }
+            }
+        }
+    }
+    OSSL_HTTP_REQ_CTX_free(rctx);
+
+    /* callback can be used to clean up TLS session */
+    if (bio_update_fn != NULL
+            && (*bio_update_fn)(cbio, arg, 0, resp != NULL) == NULL) {
+        BIO_free(resp);
+        resp = NULL;
+    }
+
+ end:
+    /*
+     * Use BIO_free_all() because bio_update_fn may prepend or append to cbio.
+     * This also frees any (e.g., SSL/TLS) BIOs linked with bio and,
+     * like BIO_reset(bio), calls SSL_shutdown() to notify/alert the peer.
+     */
+    if (bio == NULL) /* cbio was not provided by caller */
+        BIO_free_all(cbio);
+
+    if (resp != NULL)
+        /* remove any spurious error queue entries by ssl_add_cert_chain() */
+        (void)ERR_pop_to_mark();
+    else
+        (void)ERR_clear_last_mark();
+
+    return resp;
+}
+
+static int redirection_ok(int n_redir, const char *old_url, const char *new_url)
+{
+    static const char https[] = "https:";
+    int https_len = 6; /* strlen(https) */
+
+    if (n_redir >= HTTP_VERSION_MAX_REDIRECTIONS) {
+        HTTPerr(0, HTTP_R_TOO_MANY_REDIRECTIONS);
+        return 0;
+    }
+    if (*new_url == '/') /* redirection to same server => same protocol */
+        return 1;
+    if (strncmp(old_url, https, https_len) == 0 &&
+        strncmp(new_url, https, https_len) != 0) {
+        HTTPerr(0, HTTP_R_REDIRECTION_FROM_HTTPS_TO_HTTP);
+        return 0;
+    }
+    return 1;
+}
+
+/* Get data via HTTP from server at given URL, potentially with redirection */
+BIO *OSSL_HTTP_get(const char *url, const char *proxy, const char *proxy_port,
+                   BIO *bio, BIO *rbio,
+                   OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
+                   const STACK_OF(CONF_VALUE) *headers,
+                   int maxline, unsigned long max_resp_len, int timeout,
+                   const char *expected_content_type, int expect_asn1)
+{
+    time_t start_time = timeout > 0 ? time(NULL) : 0;
+    char *current_url, *redirection_url;
+    int n_redirs = 0;
+    char *host;
+    char *port;
+    char *path;
+    int use_ssl;
+    BIO *resp = NULL;
+
+    if (url == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+    if ((current_url = OPENSSL_strdup(url)) == NULL)
+        return NULL;
+
+    for (;;) {
+        if (!OSSL_HTTP_parse_url(current_url, &host, &port, &path, &use_ssl))
+            break;
+
+     new_rpath:
+        resp = OSSL_HTTP_transfer(host, port, path, use_ssl, proxy, proxy_port,
+                                  bio, rbio,
+                                  bio_update_fn, arg, headers, NULL, NULL,
+                                  maxline, max_resp_len,
+                                  update_timeout(timeout, start_time),
+                                  expected_content_type, expect_asn1,
+                                  &redirection_url);
+        OPENSSL_free(path);
+        if (resp == NULL && redirection_url != NULL) {
+            if (redirection_ok(++n_redirs, current_url, redirection_url)) {
+                (void)BIO_reset(bio);
+                OPENSSL_free(current_url);
+                current_url = redirection_url;
+                if (*redirection_url == '/') { /* redirection to same server */
+                    path = OPENSSL_strdup(redirection_url);
+                    goto new_rpath;
+                }
+                OPENSSL_free(host);
+                OPENSSL_free(port);
+                continue;
+            }
+            OPENSSL_free(redirection_url);
+        }
+        OPENSSL_free(host);
+        OPENSSL_free(port);
+        break;
+    }
+    OPENSSL_free(current_url);
+    return resp;
+}
+
+/* Get ASN.1-encoded data via HTTP from server at given URL */
+ASN1_VALUE *OSSL_HTTP_get_asn1(const char *url,
+                               const char *proxy, const char *proxy_port,
+                               BIO *bio, BIO *rbio,
+                               OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
+                               const STACK_OF(CONF_VALUE) *headers,
+                               int maxline, unsigned long max_resp_len,
+                               int timeout, const char *expected_content_type,
+                               const ASN1_ITEM *it)
+{
+    BIO *mem;
+    ASN1_VALUE *resp = NULL;
+
+    if (url == NULL || it == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+    if ((mem = OSSL_HTTP_get(url, proxy, proxy_port, bio, rbio, bio_update_fn,
+                             arg, headers, maxline, max_resp_len, timeout,
+                             expected_content_type, 1 /* expect_asn1 */))
+        != NULL)
+        resp = BIO_mem_d2i(mem, it);
+    BIO_free(mem);
+    return resp;
+}
+
+/* Post ASN.1-encoded request via HTTP to server return ASN.1 response */
+ASN1_VALUE *OSSL_HTTP_post_asn1(const char *server, const char *port,
+                                const char *path, int use_ssl,
+                                const char *proxy, const char *proxy_port,
+                                BIO *bio, BIO *rbio,
+                                OSSL_HTTP_bio_cb_t bio_update_fn, void *arg,
+                                const STACK_OF(CONF_VALUE) *headers,
+                                const char *content_type,
+                                ASN1_VALUE *req, const ASN1_ITEM *req_it,
+                                int maxline, unsigned long max_resp_len,
+                                int timeout, const char *expected_ct,
+                                const ASN1_ITEM *rsp_it)
+{
+    BIO *req_mem;
+    BIO *res_mem;
+    ASN1_VALUE *resp = NULL;
+
+    if (req == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+    /* remaining parameters are checked indirectly */
+
+    req_mem = HTTP_asn1_item2bio(req_it, req);
+    res_mem = OSSL_HTTP_transfer(server, port, path, use_ssl, proxy, proxy_port,
+                                 bio, rbio,
+                                 bio_update_fn, arg, headers, content_type,
+                                 req_mem /* may be NULL */, maxline,
+                                 max_resp_len, timeout,
+                                 expected_ct, 1 /* expect_asn1 */, NULL);
+    BIO_free(req_mem);
+    if (res_mem != NULL)
+        resp = BIO_mem_d2i(res_mem, rsp_it);
+    BIO_free(res_mem);
+    return resp;
+}
+
+/* BASE64 encoder used for encoding basic proxy authentication credentials */
+static char *base64encode(const void *buf, size_t len)
+{
+    int i;
+    size_t outl;
+    char *out;
+
+    /* Calculate size of encoded data */
+    outl = (len / 3);
+    if (len % 3 > 0)
+        outl++;
+    outl <<= 2;
+    out = OPENSSL_malloc(outl + 1);
+    if (out == NULL)
+        return 0;
+
+    i = EVP_EncodeBlock((unsigned char *)out, buf, len);
+    if (!ossl_assert(0 <= i && (size_t)i <= outl)) {
+        OPENSSL_free(out);
+        return NULL;
+    }
+    return out;
+}
+
+/*
+ * Promote the given connection BIO using the CONNECT method for a TLS proxy.
+ * This is typically called by an app, so bio_err and prog are used unless NULL
+ * to print additional diagnostic information in a user-oriented way.
+ */
+int OSSL_HTTP_proxy_connect(BIO *bio, const char *server, const char *port,
+                            const char *proxyuser, const char *proxypass,
+                            int timeout, BIO *bio_err, const char *prog)
+{
+# undef BUF_SIZE
+# define BUF_SIZE (8 * 1024)
+    char *mbuf = OPENSSL_malloc(BUF_SIZE);
+    char *mbufp;
+    int read_len = 0;
+    int rv;
+    int ret = 0;
+    BIO *fbio = BIO_new(BIO_f_buffer());
+    time_t max_time = timeout > 0 ? time(NULL) + timeout : 0;
+
+    if (bio == NULL || server == NULL || port == NULL
+            || (bio_err != NULL && prog == NULL)) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        goto end;
+    }
+
+    if (mbuf == NULL || fbio == NULL) {
+        BIO_printf(bio_err /* may be NULL */, "%s: out of memory", prog);
+        goto end;
+    }
+    BIO_push(fbio, bio);
+
+    BIO_printf(fbio, "CONNECT %s:%s "HTTP_PREFIX"1.0\r\n", server, port);
+
+    /*
+     * Workaround for broken proxies which would otherwise close
+     * the connection when entering tunnel mode (e.g., Squid 2.6)
+     */
+    BIO_printf(fbio, "Proxy-Connection: Keep-Alive\r\n");
+
+    /* Support for basic (base64) proxy authentication */
+    if (proxyuser != NULL) {
+        size_t len = strlen(proxyuser) + 1;
+        char *proxyauth, *proxyauthenc = NULL;
+
+        if (proxypass != NULL)
+            len += strlen(proxypass);
+        proxyauth = OPENSSL_malloc(len + 1);
+        if (proxyauth == NULL)
+            goto end;
+        if (BIO_snprintf(proxyauth, len + 1, "%s:%s", proxyuser,
+                         proxypass != NULL ? proxypass : "") != (int)len)
+            goto proxy_end;
+        proxyauthenc = base64encode(proxyauth, len);
+        if (proxyauthenc != NULL) {
+            BIO_printf(fbio, "Proxy-Authorization: Basic %s\r\n", proxyauthenc);
+            OPENSSL_clear_free(proxyauthenc, strlen(proxyauthenc));
+        }
+     proxy_end:
+        OPENSSL_clear_free(proxyauth, len);
+        if (proxyauthenc == NULL)
+            goto end;
+    }
+
+    /* Terminate the HTTP CONNECT request */
+    BIO_printf(fbio, "\r\n");
+
+    for (;;) {
+        if (BIO_flush(fbio) != 0)
+            break;
+        /* potentially needs to be retried if BIO is non-blocking */
+        if (!BIO_should_retry(fbio))
+            break;
+    }
+
+    for (;;) {
+        /* will not actually wait if timeout == 0 */
+        rv = BIO_wait(fbio, max_time);
+        if (rv <= 0) {
+            BIO_printf(bio_err, "%s: HTTP CONNECT %s\n", prog,
+                       rv == 0 ? "timed out" : "failed waiting for data");
+            goto end;
+        }
+
+        /*-
+         * The first line is the HTTP response.
+         * According to RFC 7230, it is formatted exactly like this:
+         * HTTP/d.d ddd Reason text\r\n
+         */
+        read_len = BIO_gets(fbio, mbuf, BUF_SIZE);
+        /* the BIO may not block, so we must wait for the 1st line to come in */
+        if (read_len < HTTP_LINE1_MINLEN)
+            continue;
+
+        /* RFC 7231 4.3.6: any 2xx status code is valid */
+        if (strncmp(mbuf, HTTP_PREFIX, strlen(HTTP_PREFIX)) != 0) {
+            HTTPerr(0, HTTP_R_SERVER_RESPONSE_PARSE_ERROR);
+            BIO_printf(bio_err, "%s: HTTP CONNECT failed, non-HTTP response\n",
+                       prog);
+            /* Wrong protocol, not even HTTP, so stop reading headers */
+            goto end;
+        }
+        mbufp = mbuf + strlen(HTTP_PREFIX);
+        if (strncmp(mbufp, HTTP_VERSION_PATT, strlen(HTTP_VERSION_PATT)) != 0) {
+            HTTPerr(0, HTTP_R_SERVER_SENT_WRONG_HTTP_VERSION);
+            BIO_printf(bio_err,
+                       "%s: HTTP CONNECT failed, bad HTTP version %.*s\n",
+                       prog, HTTP_VERSION_STR_LEN, mbufp);
+            goto end;
+        }
+        mbufp += HTTP_VERSION_STR_LEN;
+        if (strncmp(mbufp, " 2", strlen(" 2")) != 0) {
+            mbufp += 1;
+            /* chop any trailing whitespace */
+            while (read_len > 0 && ossl_isspace(mbuf[read_len - 1]))
+                read_len--;
+            mbuf[read_len] = '\0';
+            HTTPerr(0, HTTP_R_CONNECT_FAILURE);
+            ERR_add_error_data(2, "Reason=", mbufp);
+            BIO_printf(bio_err, "%s: HTTP CONNECT failed, Reason=%s\n",
+                       prog, mbufp);
+            goto end;
+        }
+        ret = 1;
+        break;
+    }
+
+    /* Read past all following headers */
+    do {
+        /*
+         * TODO: This does not necessarily catch the case when the full
+         * HTTP response came in in more than a single TCP message.
+         */
+        read_len = BIO_gets(fbio, mbuf, BUF_SIZE);
+    } while (read_len > 2);
+
+ end:
+    if (fbio != NULL) {
+        (void)BIO_flush(fbio);
+        BIO_pop(fbio);
+        BIO_free(fbio);
+    }
+    OPENSSL_free(mbuf);
+    return ret;
+# undef BUF_SIZE
+}
+
+#endif /* !defined(OPENSSL_NO_SOCK) */
diff --git a/crypto/http/http_err.c b/crypto/http/http_err.c
new file mode 100644
index 0000000000..8618539365
--- /dev/null
+++ b/crypto/http/http_err.c
@@ -0,0 +1,67 @@
+/*
+ * Generated by util/mkerr.pl DO NOT EDIT
+ * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/err.h>
+#include <openssl/httperr.h>
+
+#ifndef OPENSSL_NO_ERR
+
+static const ERR_STRING_DATA HTTP_str_reasons[] = {
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_ASN1_LEN_EXCEEDS_MAX_RESP_LEN),
+    "asn1 len exceeds max resp len"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_CONNECT_FAILURE), "connect failure"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_ERROR_PARSING_ASN1_LENGTH),
+    "error parsing asn1 length"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_ERROR_PARSING_CONTENT_LENGTH),
+    "error parsing content length"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_ERROR_PARSING_URL), "error parsing url"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_ERROR_RECEIVING), "error receiving"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_ERROR_SENDING), "error sending"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_INCONSISTENT_CONTENT_LENGTH),
+    "inconsistent content length"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_MAX_RESP_LEN_EXCEEDED),
+    "max resp len exceeded"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_MISSING_ASN1_ENCODING),
+    "missing asn1 encoding"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_MISSING_CONTENT_TYPE),
+    "missing content type"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_MISSING_REDIRECT_LOCATION),
+    "missing redirect location"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_REDIRECTION_FROM_HTTPS_TO_HTTP),
+    "redirection from https to http"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_REDIRECTION_NOT_ENABLED),
+    "redirection not enabled"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_RESPONSE_LINE_TOO_LONG),
+    "response line too long"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_SERVER_RESPONSE_PARSE_ERROR),
+    "server response parse error"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_SERVER_SENT_ERROR), "server sent error"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_SERVER_SENT_WRONG_HTTP_VERSION),
+    "server sent wrong http version"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_STATUS_CODE_UNSUPPORTED),
+    "status code unsupported"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_TLS_NOT_ENABLED), "tls not enabled"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_TOO_MANY_REDIRECTIONS),
+    "too many redirections"},
+    {ERR_PACK(ERR_LIB_HTTP, 0, HTTP_R_UNEXPECTED_CONTENT_TYPE),
+    "unexpected content type"},
+    {0, NULL}
+};
+
+#endif
+
+int ERR_load_HTTP_strings(void)
+{
+#ifndef OPENSSL_NO_ERR
+    if (ERR_reason_error_string(HTTP_str_reasons[0].error) == NULL)
+        ERR_load_strings_const(HTTP_str_reasons);
+#endif
+    return 1;
+}
diff --git a/crypto/http/http_lib.c b/crypto/http/http_lib.c
new file mode 100644
index 0000000000..1d7ad0422a
--- /dev/null
+++ b/crypto/http/http_lib.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/http.h>
+#include <openssl/httperr.h>
+#include <openssl/err.h>
+#include <string.h>
+
+/*
+ * Parse a URL and split it up into host, port and path components and
+ * whether it indicates SSL/TLS. Return 1 on success, 0 on error.
+ */
+
+int OSSL_HTTP_parse_url(const char *url, char **phost, char **pport,
+                        char **ppath, int *pssl)
+{
+    char *p, *buf;
+    char *host;
+    char *port = "80";
+
+    if (url == NULL) {
+        HTTPerr(0, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    if (phost != NULL)
+        *phost = NULL;
+    if (pport != NULL)
+        *pport = NULL;
+    if (ppath != NULL)
+        *ppath = NULL;
+    if (pssl != NULL)
+        *pssl = 0;
+
+    /* dup the buffer since we are going to mess with it */
+    if ((buf = OPENSSL_strdup(url)) == NULL)
+        goto err;
+
+    /* Check for initial colon */
+    p = strchr(buf, ':');
+    if (p == NULL || p - buf > 5 /* strlen("https") */) {
+        p = buf;
+    } else {
+        *(p++) = '\0';
+
+        if (strcmp(buf, "https") == 0) {
+            if (pssl != NULL)
+                *pssl = 1;
+            port = "443";
+        } else if (strcmp(buf, "http") != 0) {
+            goto parse_err;
+        }
+
+        /* Check for double slash */
+        if ((p[0] != '/') || (p[1] != '/'))
+            goto parse_err;
+        p += 2;
+    }
+    host = p;
+
+    /* Check for trailing part of path */
+    p = strchr(p, '/');
+    if (ppath != NULL && (*ppath = OPENSSL_strdup(p == NULL ? "/" : p)) == NULL)
+        goto err;
+    if (p != NULL)
+        *p = '\0'; /* Set start of path to 0 so hostname[:port] is valid */
+
+    p = host;
+    if (host[0] == '[') {
+        /* ipv6 literal */
+        host++;
+        p = strchr(host, ']');
+        if (p == NULL)
+            goto parse_err;
+        *p = '\0';
+        p++;
+    }
+
+    /* Look for optional ':' for port number */
+    if ((p = strchr(p, ':'))) {
+        *p = '\0';
+        port = p + 1;
+    }
+    if (phost != NULL && (*phost = OPENSSL_strdup(host)) == NULL)
+        goto err;
+    if (pport != NULL && (*pport = OPENSSL_strdup(port)) == NULL)
+        goto err;
+
+    OPENSSL_free(buf);
+    return 1;
+
+ parse_err:
+    HTTPerr(0, HTTP_R_ERROR_PARSING_URL);
+
+ err:
+    if (ppath != NULL) {
+        OPENSSL_free(*ppath);
+        *ppath = NULL;
+    }
+    if (pport != NULL) {
+        OPENSSL_free(*pport);
+        *pport = NULL;
+    }
+    if (phost != NULL) {
+        OPENSSL_free(*phost);
+        *phost = NULL;
+    }
+    OPENSSL_free(buf);
+    return 0;
+}
diff --git a/crypto/http/http_local.h b/crypto/http/http_local.h
new file mode 100644
index 0000000000..33457f1e09
--- /dev/null
+++ b/crypto/http/http_local.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2007-2020 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright Siemens AG 2018-2020
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef OSSL_CRYPTO_HTTP_LOCAL_H
+# define OSSL_CRYPTO_HTTP_LOCAL_H
+
+# include <openssl/ocsp.h>
+
+/* name aliases for legacy names with name prefix "OCSP_" */
+typedef OCSP_REQ_CTX OSSL_HTTP_REQ_CTX;
+/* functions meanwhile only used internally */
+# define OSSL_HTTP_REQ_CTX_new          OCSP_REQ_CTX_new
+# define OSSL_HTTP_REQ_CTX_free         OCSP_REQ_CTX_free
+# define OSSL_HTTP_REQ_CTX_header       OCSP_REQ_CTX_http
+# define OSSL_HTTP_REQ_CTX_add1_header  OCSP_REQ_CTX_add1_header
+# define OSSL_HTTP_REQ_CTX_i2d          OCSP_REQ_CTX_i2d
+# define OSSL_HTTP_REQ_CTX_nbio         OCSP_REQ_CTX_nbio
+# ifndef OPENSSL_NO_SOCK
+#  define OSSL_HTTP_REQ_CTX_sendreq_d2i OCSP_REQ_CTX_nbio_d2i
+# endif
+/* functions that are meanwhile unused */
+# define OSSL_HTTP_REQ_CTX_get0_mem_bio OCSP_REQ_CTX_get0_mem_bio /* undoc'd */
+# define OSSL_HTTP_REQ_CTX_set_max_response_length OCSP_set_max_response_length
+
+BIO *HTTP_asn1_item2bio(const ASN1_ITEM *it, ASN1_VALUE *val);
+OSSL_HTTP_REQ_CTX *HTTP_REQ_CTX_new(BIO *wbio, BIO *rbio, int use_http_proxy,
+                                    const char *server, const char *port,
+                                    const char *path,
+                                    const STACK_OF(CONF_VALUE) *headers,
+                                    const char *content_type, BIO *req_mem,
+                                    int maxline, unsigned long max_resp_len,
+                                    int timeout,
+                                    const char *expected_content_type,
+                                    int expect_asn1);
+ASN1_VALUE *HTTP_sendreq_bio(BIO *bio, OSSL_HTTP_bio_cb_t bio_update_fn,
+                             void *arg, const char *server, const char *port,
+                             const char *path, int use_ssl, int use_proxy,
+                             const STACK_OF(CONF_VALUE) *headers,
+                             const char *content_type,
+                             ASN1_VALUE *req, const ASN1_ITEM *req_it,
+                             int maxline, unsigned long max_resp_len,
+                             int timeout, const ASN1_ITEM *rsp_it);
+
+#endif /* !defined OSSL_CRYPTO_HTTP_LOCAL_H */