343 lines
11 KiB
C
343 lines
11 KiB
C
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/* http_get_bearssl - HTTPS version of the http_get example, using BearSSL.
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*
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* Retrieves a JSON response from the howsmyssl.com API via HTTPS over TLS v1.2.
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*
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* Validates the server's certificate using a hardcoded public key.
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*
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* Adapted from the client_basic sample in BearSSL.
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*
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* Original Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>, MIT License.
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* Additions Copyright (C) 2016 Stefan Schake, MIT License.
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*/
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#include "espressif/esp_common.h"
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#include "esp/uart.h"
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#include "esp/hwrand.h"
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#include <string.h>
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#include "FreeRTOS.h"
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#include "task.h"
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#include "lwip/err.h"
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#include "lwip/sockets.h"
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#include "lwip/sys.h"
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#include "lwip/netdb.h"
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#include "lwip/dns.h"
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#include "lwip/api.h"
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#include "ssid_config.h"
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#include "bearssl.h"
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#define CLOCK_SECONDS_PER_MINUTE (60UL)
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#define CLOCK_MINUTES_PER_HOUR (60UL)
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#define CLOCK_HOURS_PER_DAY (24UL)
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#define CLOCK_SECONDS_PER_HOUR (CLOCK_MINUTES_PER_HOUR*CLOCK_SECONDS_PER_MINUTE)
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#define CLOCK_SECONDS_PER_DAY (CLOCK_HOURS_PER_DAY*CLOCK_SECONDS_PER_HOUR)
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#define WEB_SERVER "www.howsmyssl.com"
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#define WEB_PORT "443"
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#define WEB_URL "https://www.howsmyssl.com/a/check"
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#define GET_REQUEST "GET "WEB_URL" HTTP/1.1\nHost: "WEB_SERVER"\n\n"
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/*
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* Low-level data read callback for the simplified SSL I/O API.
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*/
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static int
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sock_read(void *ctx, unsigned char *buf, size_t len)
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{
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for (;;) {
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ssize_t rlen;
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rlen = read(*(int *)ctx, buf, len);
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if (rlen <= 0) {
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if (rlen < 0 && errno == EINTR) {
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continue;
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}
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return -1;
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}
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return (int)rlen;
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}
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}
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/*
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* Low-level data write callback for the simplified SSL I/O API.
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*/
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static int
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sock_write(void *ctx, const unsigned char *buf, size_t len)
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{
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for (;;) {
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ssize_t wlen;
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wlen = write(*(int *)ctx, buf, len);
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if (wlen <= 0) {
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if (wlen < 0 && errno == EINTR) {
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continue;
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}
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return -1;
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}
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return (int)wlen;
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}
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}
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/*
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* The hardcoded trust anchors. These are the two DN + public key that
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* correspond to the self-signed certificates cert-root-rsa.pem and
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* cert-root-ec.pem.
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*
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* C code for hardcoded trust anchors can be generated with the "brssl"
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* command-line tool (with the "ta" command).
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*
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* Below is the imported "Let's Encrypt" root certificate, as howsmyssl
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* is depending on it:
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*
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* https://letsencrypt.org/certs/letsencryptauthorityx3.pem
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*
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*/
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static const unsigned char TA0_DN[] = {
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0x30, 0x4A, 0x31, 0x0B, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13,
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0x02, 0x55, 0x53, 0x31, 0x16, 0x30, 0x14, 0x06, 0x03, 0x55, 0x04, 0x0A,
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0x13, 0x0D, 0x4C, 0x65, 0x74, 0x27, 0x73, 0x20, 0x45, 0x6E, 0x63, 0x72,
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0x79, 0x70, 0x74, 0x31, 0x23, 0x30, 0x21, 0x06, 0x03, 0x55, 0x04, 0x03,
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0x13, 0x1A, 0x4C, 0x65, 0x74, 0x27, 0x73, 0x20, 0x45, 0x6E, 0x63, 0x72,
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0x79, 0x70, 0x74, 0x20, 0x41, 0x75, 0x74, 0x68, 0x6F, 0x72, 0x69, 0x74,
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0x79, 0x20, 0x58, 0x33
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};
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static const unsigned char TA0_RSA_N[] = {
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0x9C, 0xD3, 0x0C, 0xF0, 0x5A, 0xE5, 0x2E, 0x47, 0xB7, 0x72, 0x5D, 0x37,
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0x83, 0xB3, 0x68, 0x63, 0x30, 0xEA, 0xD7, 0x35, 0x26, 0x19, 0x25, 0xE1,
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0xBD, 0xBE, 0x35, 0xF1, 0x70, 0x92, 0x2F, 0xB7, 0xB8, 0x4B, 0x41, 0x05,
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0xAB, 0xA9, 0x9E, 0x35, 0x08, 0x58, 0xEC, 0xB1, 0x2A, 0xC4, 0x68, 0x87,
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0x0B, 0xA3, 0xE3, 0x75, 0xE4, 0xE6, 0xF3, 0xA7, 0x62, 0x71, 0xBA, 0x79,
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0x81, 0x60, 0x1F, 0xD7, 0x91, 0x9A, 0x9F, 0xF3, 0xD0, 0x78, 0x67, 0x71,
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0xC8, 0x69, 0x0E, 0x95, 0x91, 0xCF, 0xFE, 0xE6, 0x99, 0xE9, 0x60, 0x3C,
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0x48, 0xCC, 0x7E, 0xCA, 0x4D, 0x77, 0x12, 0x24, 0x9D, 0x47, 0x1B, 0x5A,
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0xEB, 0xB9, 0xEC, 0x1E, 0x37, 0x00, 0x1C, 0x9C, 0xAC, 0x7B, 0xA7, 0x05,
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0xEA, 0xCE, 0x4A, 0xEB, 0xBD, 0x41, 0xE5, 0x36, 0x98, 0xB9, 0xCB, 0xFD,
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0x6D, 0x3C, 0x96, 0x68, 0xDF, 0x23, 0x2A, 0x42, 0x90, 0x0C, 0x86, 0x74,
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0x67, 0xC8, 0x7F, 0xA5, 0x9A, 0xB8, 0x52, 0x61, 0x14, 0x13, 0x3F, 0x65,
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0xE9, 0x82, 0x87, 0xCB, 0xDB, 0xFA, 0x0E, 0x56, 0xF6, 0x86, 0x89, 0xF3,
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0x85, 0x3F, 0x97, 0x86, 0xAF, 0xB0, 0xDC, 0x1A, 0xEF, 0x6B, 0x0D, 0x95,
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0x16, 0x7D, 0xC4, 0x2B, 0xA0, 0x65, 0xB2, 0x99, 0x04, 0x36, 0x75, 0x80,
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0x6B, 0xAC, 0x4A, 0xF3, 0x1B, 0x90, 0x49, 0x78, 0x2F, 0xA2, 0x96, 0x4F,
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0x2A, 0x20, 0x25, 0x29, 0x04, 0xC6, 0x74, 0xC0, 0xD0, 0x31, 0xCD, 0x8F,
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0x31, 0x38, 0x95, 0x16, 0xBA, 0xA8, 0x33, 0xB8, 0x43, 0xF1, 0xB1, 0x1F,
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0xC3, 0x30, 0x7F, 0xA2, 0x79, 0x31, 0x13, 0x3D, 0x2D, 0x36, 0xF8, 0xE3,
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0xFC, 0xF2, 0x33, 0x6A, 0xB9, 0x39, 0x31, 0xC5, 0xAF, 0xC4, 0x8D, 0x0D,
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0x1D, 0x64, 0x16, 0x33, 0xAA, 0xFA, 0x84, 0x29, 0xB6, 0xD4, 0x0B, 0xC0,
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0xD8, 0x7D, 0xC3, 0x93
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};
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static const unsigned char TA0_RSA_E[] = {
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0x01, 0x00, 0x01
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};
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static const br_x509_trust_anchor TAs[1] = {
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{
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{ (unsigned char *)TA0_DN, sizeof TA0_DN },
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BR_X509_TA_CA,
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{
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BR_KEYTYPE_RSA,
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{ .rsa = {
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(unsigned char *)TA0_RSA_N, sizeof TA0_RSA_N,
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(unsigned char *)TA0_RSA_E, sizeof TA0_RSA_E,
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} }
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}
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}
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};
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#define TAs_NUM 1
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/*
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* Buffer to store a record + BearSSL state
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* We use MONO mode to save 16k of RAM.
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* This could be even smaller by using max_fragment_len, but
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* the howsmyssl.com server doesn't seem to support it.
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*/
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static unsigned char bearssl_buffer[BR_SSL_BUFSIZE_MONO];
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static br_ssl_client_context sc;
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static br_x509_minimal_context xc;
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static br_sslio_context ioc;
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void http_get_task(void *pvParameters)
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{
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int successes = 0, failures = 0;
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int provisional_time = 0;
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while (1) {
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/*
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* Wait until we can resolve the DNS for the server, as an indication
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* our network is probably working...
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*/
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const struct addrinfo hints = {
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.ai_family = AF_INET,
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.ai_socktype = SOCK_STREAM,
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};
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struct addrinfo *res = NULL;
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int dns_err = 0;
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do {
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if (res)
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freeaddrinfo(res);
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vTaskDelay(1000 / portTICK_PERIOD_MS);
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dns_err = getaddrinfo(WEB_SERVER, WEB_PORT, &hints, &res);
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} while(dns_err != 0 || res == NULL);
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int fd = socket(res->ai_family, res->ai_socktype, 0);
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if (fd < 0) {
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freeaddrinfo(res);
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printf("socket failed\n");
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failures++;
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continue;
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}
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printf("Initializing BearSSL... ");
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br_ssl_client_init_full(&sc, &xc, TAs, TAs_NUM);
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/*
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* Set the I/O buffer to the provided array. We allocated a
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* buffer large enough for full-duplex behaviour with all
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* allowed sizes of SSL records, hence we set the last argument
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* to 1 (which means "split the buffer into separate input and
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* output areas").
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*/
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br_ssl_engine_set_buffer(&sc.eng, bearssl_buffer, sizeof bearssl_buffer, 0);
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/*
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* Inject some entropy from the ESP hardware RNG
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* This is necessary because we don't support any of the BearSSL methods
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*/
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for (int i = 0; i < 10; i++) {
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int rand = hwrand();
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br_ssl_engine_inject_entropy(&sc.eng, &rand, 4);
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}
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/*
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* Reset the client context, for a new handshake. We provide the
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* target host name: it will be used for the SNI extension. The
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* last parameter is 0: we are not trying to resume a session.
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*/
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br_ssl_client_reset(&sc, WEB_SERVER, 0);
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/*
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* Initialise the simplified I/O wrapper context, to use our
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* SSL client context, and the two callbacks for socket I/O.
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*/
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br_sslio_init(&ioc, &sc.eng, sock_read, &fd, sock_write, &fd);
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printf("done.\r\n");
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/* FIXME: set date & time using epoch time precompiler flag for now */
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provisional_time = CONFIG_EPOCH_TIME + (xTaskGetTickCount()/configTICK_RATE_HZ);
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xc.days = (provisional_time / CLOCK_SECONDS_PER_DAY) + 719528;
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xc.seconds = provisional_time % CLOCK_SECONDS_PER_DAY;
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printf("Time: %02i:%02i\r\n",
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(int)(xc.seconds / CLOCK_SECONDS_PER_HOUR),
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(int)((xc.seconds % CLOCK_SECONDS_PER_HOUR)/CLOCK_SECONDS_PER_MINUTE)
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);
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if (connect(fd, res->ai_addr, res->ai_addrlen) != 0)
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{
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close(fd);
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freeaddrinfo(res);
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printf("connect failed\n");
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failures++;
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continue;
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}
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printf("Connected\r\n");
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/*
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* Note that while the context has, at that point, already
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* assembled the ClientHello to send, nothing happened on the
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* network yet. Real I/O will occur only with the next call.
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*
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* We write our simple HTTP request. We test the call
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* for an error (-1), but this is not strictly necessary, since
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* the error state "sticks": if the context fails for any reason
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* (e.g. bad server certificate), then it will remain in failed
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* state and all subsequent calls will return -1 as well.
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*/
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if (br_sslio_write_all(&ioc, GET_REQUEST, strlen(GET_REQUEST)) != BR_ERR_OK) {
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close(fd);
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freeaddrinfo(res);
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printf("br_sslio_write_all failed: %d\r\n", br_ssl_engine_last_error(&sc.eng));
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failures++;
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continue;
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}
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/*
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* SSL is a buffered protocol: we make sure that all our request
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* bytes are sent onto the wire.
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*/
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br_sslio_flush(&ioc);
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/*
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* Read and print the server response
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*/
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for (;;)
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{
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int rlen;
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unsigned char buf[128];
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bzero(buf, 128);
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// Leave the final byte for zero termination
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rlen = br_sslio_read(&ioc, buf, sizeof(buf) - 1);
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if (rlen < 0) {
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break;
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}
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if (rlen > 0) {
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printf("%s", buf);
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}
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}
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/*
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* If reading the response failed for any reason, we detect it here
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*/
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if (br_ssl_engine_last_error(&sc.eng) != BR_ERR_OK) {
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close(fd);
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freeaddrinfo(res);
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printf("failure, error = %d\r\n", br_ssl_engine_last_error(&sc.eng));
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failures++;
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continue;
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}
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printf("\r\n\r\nfree heap pre = %u\r\n", xPortGetFreeHeapSize());
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/*
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* Close the connection and start over after a delay
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*/
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close(fd);
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freeaddrinfo(res);
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printf("free heap post = %u\r\n", xPortGetFreeHeapSize());
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successes++;
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printf("successes = %d failures = %d\r\n", successes, failures);
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for(int countdown = 10; countdown >= 0; countdown--) {
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printf("%d...\n", countdown);
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vTaskDelay(1000 / portTICK_PERIOD_MS);
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}
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||
|
|
printf("Starting again!\r\n\r\n");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void user_init(void)
|
||
|
|
{
|
||
|
|
uart_set_baud(0, 115200);
|
||
|
|
printf("SDK version:%s\n", sdk_system_get_sdk_version());
|
||
|
|
|
||
|
|
struct sdk_station_config config = {
|
||
|
|
.ssid = WIFI_SSID,
|
||
|
|
.password = WIFI_PASS,
|
||
|
|
};
|
||
|
|
|
||
|
|
/* required to call wifi_set_opmode before station_set_config */
|
||
|
|
sdk_wifi_set_opmode(STATION_MODE);
|
||
|
|
sdk_wifi_station_set_config(&config);
|
||
|
|
|
||
|
|
xTaskCreate(&http_get_task, "get_task", 2048, NULL, 2, NULL);
|
||
|
|
}
|