Extract HTTP server code from apps/ocsp.c to apps/lib/http_server.c

Also adds apps/include/http_server.h.
This is used so far by apps/ocsp.c and is going to be used for apps/cmp.c
and will be helpful also for any future app acting as HTTP server.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11736)

1 files changed, 394 insertions, 0 deletions

diff --git a/apps/lib/http_server.c b/apps/lib/http_server.c
new file mode 100644
index 0000000000..6db11f4150
--- /dev/null
+++ b/apps/lib/http_server.c
@@ -0,0 +1,394 @@
+/*
+ * Copyright 1995-2020 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
+ */
+
+/* Very basic HTTP server */
+
+#if !defined(_POSIX_C_SOURCE) && defined(OPENSSL_SYS_VMS)
+/*
+ * On VMS, you need to define this to get the declaration of fileno().  The
+ * value 2 is to make sure no function defined in POSIX-2 is left undefined.
+ */
+# define _POSIX_C_SOURCE 2
+#endif
+
+#include <ctype.h>
+#include "http_server.h"
+#include "internal/sockets.h"
+#include <openssl/err.h>
+#include <openssl/rand.h>
+
+int multi = 0; /* run multiple responder processes */
+
+#ifdef HTTP_DAEMON
+int acfd = (int) INVALID_SOCKET;
+#endif
+
+#ifdef HTTP_DAEMON
+static int print_syslog(const char *str, size_t len, void *levPtr)
+{
+    int level = *(int *)levPtr;
+    int ilen = len > MAXERRLEN ? MAXERRLEN : len;
+
+    syslog(level, "%.*s", ilen, str);
+
+    return ilen;
+}
+#endif
+
+void log_message(const char *prog, int level, const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+#ifdef HTTP_DAEMON
+    if (multi) {
+        char buf[1024];
+
+        if (vsnprintf(buf, sizeof(buf), fmt, ap) > 0)
+            syslog(level, "%s", buf);
+        if (level >= LOG_ERR)
+            ERR_print_errors_cb(print_syslog, &level);
+    }
+#endif
+    if (!multi) {
+        BIO_printf(bio_err, "%s: ", prog);
+        BIO_vprintf(bio_err, fmt, ap);
+        BIO_printf(bio_err, "\n");
+    }
+    va_end(ap);
+}
+
+#ifdef HTTP_DAEMON
+void socket_timeout(int signum)
+{
+    if (acfd != (int)INVALID_SOCKET)
+        (void)shutdown(acfd, SHUT_RD);
+}
+
+static void killall(int ret, pid_t *kidpids)
+{
+    int i;
+
+    for (i = 0; i < multi; ++i)
+        if (kidpids[i] != 0)
+            (void)kill(kidpids[i], SIGTERM);
+    OPENSSL_free(kidpids);
+    sleep(1);
+    exit(ret);
+}
+
+static int termsig = 0;
+
+static void noteterm(int sig)
+{
+    termsig = sig;
+}
+
+/*
+ * Loop spawning up to `multi` child processes, only child processes return
+ * from this function.  The parent process loops until receiving a termination
+ * signal, kills extant children and exits without returning.
+ */
+void spawn_loop(const char *prog)
+{
+    pid_t *kidpids = NULL;
+    int status;
+    int procs = 0;
+    int i;
+
+    openlog(prog, LOG_PID, LOG_DAEMON);
+
+    if (setpgid(0, 0)) {
+        syslog(LOG_ERR, "fatal: error detaching from parent process group: %s",
+               strerror(errno));
+        exit(1);
+    }
+    kidpids = app_malloc(multi * sizeof(*kidpids), "child PID array");
+    for (i = 0; i < multi; ++i)
+        kidpids[i] = 0;
+
+    signal(SIGINT, noteterm);
+    signal(SIGTERM, noteterm);
+
+    while (termsig == 0) {
+        pid_t fpid;
+
+        /*
+         * Wait for a child to replace when we're at the limit.
+         * Slow down if a child exited abnormally or waitpid() < 0
+         */
+        while (termsig == 0 && procs >= multi) {
+            if ((fpid = waitpid(-1, &status, 0)) > 0) {
+                for (i = 0; i < procs; ++i) {
+                    if (kidpids[i] == fpid) {
+                        kidpids[i] = 0;
+                        --procs;
+                        break;
+                    }
+                }
+                if (i >= multi) {
+                    syslog(LOG_ERR, "fatal: internal error: "
+                           "no matching child slot for pid: %ld",
+                           (long) fpid);
+                    killall(1, kidpids);
+                }
+                if (status != 0) {
+                    if (WIFEXITED(status))
+                        syslog(LOG_WARNING, "child process: %ld, exit status: %d",
+                               (long)fpid, WEXITSTATUS(status));
+                    else if (WIFSIGNALED(status))
+                        syslog(LOG_WARNING, "child process: %ld, term signal %d%s",
+                               (long)fpid, WTERMSIG(status),
+# ifdef WCOREDUMP
+                               WCOREDUMP(status) ? " (core dumped)" :
+# endif
+                               "");
+                    sleep(1);
+                }
+                break;
+            } else if (errno != EINTR) {
+                syslog(LOG_ERR, "fatal: waitpid(): %s", strerror(errno));
+                killall(1, kidpids);
+            }
+        }
+        if (termsig)
+            break;
+
+        switch (fpid = fork()) {
+        case -1: /* error */
+            /* System critically low on memory, pause and try again later */
+            sleep(30);
+            break;
+        case 0: /* child */
+            OPENSSL_free(kidpids);
+            signal(SIGINT, SIG_DFL);
+            signal(SIGTERM, SIG_DFL);
+            if (termsig)
+                _exit(0);
+            if (RAND_poll() <= 0) {
+                syslog(LOG_ERR, "fatal: RAND_poll() failed");
+                _exit(1);
+            }
+            return;
+        default:            /* parent */
+            for (i = 0; i < multi; ++i) {
+                if (kidpids[i] == 0) {
+                    kidpids[i] = fpid;
+                    procs++;
+                    break;
+                }
+            }
+            if (i >= multi) {
+                syslog(LOG_ERR, "fatal: internal error: no free child slots");
+                killall(1, kidpids);
+            }
+            break;
+        }
+    }
+
+    /* The loop above can only break on termsig */
+    syslog(LOG_INFO, "terminating on signal: %d", termsig);
+    killall(0, kidpids);
+}
+#endif
+
+#ifndef OPENSSL_NO_SOCK
+BIO *http_server_init_bio(const char *prog, const char *port)
+{
+    BIO *acbio = NULL, *bufbio;
+
+    bufbio = BIO_new(BIO_f_buffer());
+    if (bufbio == NULL)
+        goto err;
+    acbio = BIO_new(BIO_s_accept());
+    if (acbio == NULL
+        || BIO_set_bind_mode(acbio, BIO_BIND_REUSEADDR) < 0
+        || BIO_set_accept_port(acbio, port) < 0) {
+        log_message(prog, LOG_ERR, "Error setting up accept BIO");
+        goto err;
+    }
+
+    BIO_set_accept_bios(acbio, bufbio);
+    bufbio = NULL;
+    if (BIO_do_accept(acbio) <= 0) {
+        log_message(prog, LOG_ERR, "Error starting accept");
+        goto err;
+    }
+
+    return acbio;
+
+ err:
+    BIO_free_all(acbio);
+    BIO_free(bufbio);
+    return NULL;
+}
+
+/*
+ * Decode %xx URL-decoding in-place. Ignores malformed sequences.
+ */
+static int urldecode(char *p)
+{
+    unsigned char *out = (unsigned char *)p;
+    unsigned char *save = out;
+
+    for (; *p; p++) {
+        if (*p != '%') {
+            *out++ = *p;
+        } else if (isxdigit(_UC(p[1])) && isxdigit(_UC(p[2]))) {
+            /* Don't check, can't fail because of ixdigit() call. */
+            *out++ = (OPENSSL_hexchar2int(p[1]) << 4)
+                | OPENSSL_hexchar2int(p[2]);
+            p += 2;
+        } else {
+            return -1;
+        }
+    }
+    *out = '\0';
+    return (int)(out - save);
+}
+
+int http_server_get_asn1_req(const ASN1_ITEM *it, ASN1_VALUE **preq,
+                             BIO **pcbio, BIO *acbio,
+                             const char *prog, int accept_get, int timeout)
+{
+    BIO *cbio = NULL, *getbio = NULL, *b64 = NULL;
+    int len;
+    char reqbuf[2048], inbuf[2048];
+    char *url, *end;
+    ASN1_VALUE *req;
+    int ret = 1;
+
+    *preq = NULL;
+    *pcbio = NULL;
+
+    /* Connection loss before accept() is routine, ignore silently */
+    if (BIO_do_accept(acbio) <= 0)
+        return 0;
+
+    cbio = BIO_pop(acbio);
+    *pcbio = cbio;
+    if (cbio == NULL) {
+        ret = -1;
+        goto out;
+    }
+
+# ifdef HTTP_DAEMON
+    if (timeout > 0) {
+        (void)BIO_get_fd(cbio, &acfd);
+        alarm(timeout);
+    }
+# endif
+
+    /* Read the request line. */
+    len = BIO_gets(cbio, reqbuf, sizeof(reqbuf));
+    if (len <= 0)
+        goto out;
+
+    if (accept_get && strncmp(reqbuf, "GET ", 4) == 0) {
+        /* Expecting GET {sp} /URL {sp} HTTP/1.x */
+        for (url = reqbuf + 4; *url == ' '; ++url)
+            continue;
+        if (*url != '/') {
+            log_message(prog, LOG_INFO,
+                        "Invalid GET -- URL does not begin with '/': %s", url);
+            goto out;
+        }
+        url++;
+
+        /* Splice off the HTTP version identifier. */
+        for (end = url; *end != '\0'; end++)
+            if (*end == ' ')
+                break;
+        if (strncmp(end, " HTTP/1.", 7) != 0) {
+            log_message(prog, LOG_INFO,
+                        "Invalid GET -- bad HTTP/version string: %s", end + 1);
+            goto out;
+        }
+        *end = '\0';
+
+        /*-
+         * Skip "GET / HTTP..." requests often used by load-balancers.
+         * 'url' was incremented above to point to the first byte *after*
+         * the leading slash, so in case 'GET / ' it is now an empty string.
+         */
+        if (url[0] == '\0')
+            goto out;
+
+        len = urldecode(url);
+        if (len <= 0) {
+            log_message(prog, LOG_INFO,
+                        "Invalid GET request -- bad URL encoding: %s", url);
+            goto out;
+        }
+        if ((getbio = BIO_new_mem_buf(url, len)) == NULL
+            || (b64 = BIO_new(BIO_f_base64())) == NULL) {
+            log_message(prog, LOG_ERR,
+                        "Could not allocate base64 bio with size = %d", len);
+            BIO_free_all(cbio);
+            *pcbio = NULL;
+            ret = -1;
+            goto out;
+        }
+        BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
+        getbio = BIO_push(b64, getbio);
+    } else if (strncmp(reqbuf, "POST ", 5) != 0) {
+        log_message(prog, LOG_INFO,
+                    "HTTP request does not start with GET/POST: %s", reqbuf);
+        /* TODO provide better diagnosis in case client tries TLS */
+        goto out;
+    }
+
+    /* Read and skip past the headers. */
+    for (;;) {
+        len = BIO_gets(cbio, inbuf, sizeof(inbuf));
+        if (len <= 0) {
+            log_message(prog, LOG_ERR,
+                        "Error skipping remaining HTTP headers");
+            goto out;
+        }
+        if ((inbuf[0] == '\r') || (inbuf[0] == '\n'))
+            break;
+    }
+
+# ifdef HTTP_DAEMON
+    /* Clear alarm before we close the client socket */
+    alarm(0);
+    timeout = 0;
+# endif
+
+    /* Try to read and parse request */
+    req = ASN1_item_d2i_bio(it, getbio != NULL ? getbio : cbio, NULL);
+    if (req == NULL)
+        log_message(prog, LOG_ERR, "Error parsing request");
+
+    *preq = req;
+
+ out:
+    BIO_free_all(getbio);
+# ifdef HTTP_DAEMON
+    if (timeout > 0)
+        alarm(0);
+    acfd = (int)INVALID_SOCKET;
+# endif
+    return ret;
+}
+
+/* assumes that cbio does not do an encoding that changes the output length */
+int http_server_send_asn1_resp(BIO *cbio, const char *content_type,
+                               const ASN1_ITEM *it, const ASN1_VALUE *resp)
+{
+    int ret = BIO_printf(cbio, "HTTP/1.0 200 OK\r\nContent-type: %s\r\n"
+                         "Content-Length: %d\r\n\r\n", content_type,
+                         ASN1_item_i2d(resp, NULL, it)) > 0
+            && ASN1_item_i2d_bio(it, cbio, resp) > 0;
+
+    (void)BIO_flush(cbio);
+    return ret;
+}
+#endif