http_server.c
/*
* 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 <string.h>
#include <ctype.h>
#include "http_server.h"
#include "internal/sockets.h"
#include <openssl/err.h>
#include <openssl/rand.h>
#if defined(__TANDEM)
# if defined(OPENSSL_TANDEM_FLOSS)
# include <floss.h(floss_fork)>
# endif
#endif
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,
char **ppath, 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 *meth, *url, *end;
ASN1_VALUE *req;
int ret = 1;
*preq = NULL;
if (ppath != NULL)
*ppath = 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) {
/* Cannot call http_server_send_status(cbio, ...) */
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) {
log_message(prog, LOG_INFO,
"Request line read error or empty request");
(void)http_server_send_status(cbio, 400, "Bad Request");
goto out;
}
meth = reqbuf;
url = meth + 3;
if ((accept_get && strncmp(meth, "GET ", 4) == 0)
|| (url++, strncmp(meth, "POST ", 5) == 0)) {
/* Expecting (GET|POST) {sp} /URL {sp} HTTP/1.x */
*(url++) = '\0';
while (*url == ' ')
url++;
if (*url != '/') {
log_message(prog, LOG_INFO,
"Invalid %s -- URL does not begin with '/': %s",
meth, url);
(void)http_server_send_status(cbio, 400, "Bad Request");
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 %s -- bad HTTP/version string: %s",
meth, end + 1);
(void)http_server_send_status(cbio, 400, "Bad Request");
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 (strlen(meth) == 3 && url[0] == '\0') {
(void)http_server_send_status(cbio, 200, "OK");
goto out;
}
len = urldecode(url);
if (len < 0) {
log_message(prog, LOG_INFO,
"Invalid %s request -- bad URL encoding: %s",
meth, url);
(void)http_server_send_status(cbio, 400, "Bad Request");
goto out;
}
if (strlen(meth) == 3) { /* GET */
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);
goto fatal;
}
BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
getbio = BIO_push(b64, getbio);
}
} else {
log_message(prog, LOG_INFO,
"HTTP request does not start with GET/POST: %s", reqbuf);
/* TODO provide better diagnosis in case client tries TLS */
(void)http_server_send_status(cbio, 400, "Bad Request");
goto out;
}
/* chop any further/duplicate leading or trailing '/' */
while (*url == '/')
url++;
while (end >= url + 2 && end[-2] == '/' && end[-1] == '/')
end--;
*end = '\0';
/* 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");
(void)http_server_send_status(cbio, 400, "Bad Request");
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");
} else if (ppath != NULL && (*ppath = OPENSSL_strdup(url)) == NULL) {
log_message(prog, LOG_ERR,
"Out of memory allocating %zu bytes", strlen(url) + 1);
ASN1_item_free(req, it);
goto fatal;
}
*preq = req;
out:
BIO_free_all(getbio);
# ifdef HTTP_DAEMON
if (timeout > 0)
alarm(0);
acfd = (int)INVALID_SOCKET;
# endif
return ret;
fatal:
(void)http_server_send_status(cbio, 500, "Internal Server Error");
if (ppath != NULL) {
OPENSSL_free(*ppath);
*ppath = NULL;
}
BIO_free_all(cbio);
*pcbio = NULL;
ret = -1;
goto out;
}
/* 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;
}
int http_server_send_status(BIO *cbio, int status, const char *reason)
{
int ret = BIO_printf(cbio, "HTTP/1.0 %d %s\r\n\r\n", status, reason) > 0;
(void)BIO_flush(cbio);
return ret;
}
#endif
