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SSL examples: updates (#8643)

Simplify SSL+ethernet example, reuse/include WiFi example
This commit is contained in:
david gauchard
2022-07-27 23:47:10 +02:00
committed by GitHub
parent e2a36ed6c2
commit 646bdfc060
7 changed files with 107 additions and 297 deletions

View File

@ -11,185 +11,9 @@
Wiznet5500lwIP eth(/*SS*/ 16); // <== adapt to your hardware
#include <WiFiClientSecure.h>
#include <StackThunk.h>
#include <time.h>
#include "certs.h"
const char *path = "/";
// Set time via NTP, as required for x.509 validation
void setClock() {
configTime(3 * 3600, 0, "pool.ntp.org", "time.nist.gov");
Serial.print("Waiting for NTP time sync: ");
time_t now = time(nullptr);
while (now < 8 * 3600 * 2) {
delay(500);
Serial.print(".");
now = time(nullptr);
}
Serial.println("");
struct tm timeinfo;
gmtime_r(&now, &timeinfo);
Serial.print("Current time: ");
Serial.print(asctime(&timeinfo));
}
// Try and connect using a WiFiClientBearSSL to specified host:port and dump HTTP response
void fetchURL(BearSSL::WiFiClientSecure *client, const char *host, const uint16_t port, const char *path) {
if (!path) {
path = "/";
}
ESP.resetFreeContStack();
uint32_t freeStackStart = ESP.getFreeContStack();
Serial.printf("Trying: %s:443...", host);
client->connect(host, port);
if (!client->connected()) {
Serial.printf("*** Can't connect. ***\n-------\n");
return;
}
Serial.printf("Connected!\n-------\n");
client->write("GET ");
client->write(path);
client->write(" HTTP/1.0\r\nHost: ");
client->write(host);
client->write("\r\nUser-Agent: ESP8266\r\n");
client->write("\r\n");
uint32_t to = millis() + 5000;
if (client->connected()) {
do {
char tmp[32];
memset(tmp, 0, 32);
int rlen = client->read((uint8_t *)tmp, sizeof(tmp) - 1);
yield();
if (rlen < 0) {
break;
}
// Only print out first line up to \r, then abort connection
char *nl = strchr(tmp, '\r');
if (nl) {
*nl = 0;
Serial.print(tmp);
break;
}
Serial.print(tmp);
} while (millis() < to);
}
client->stop();
uint32_t freeStackEnd = ESP.getFreeContStack();
Serial.printf("\nCONT stack used: %d\n", freeStackStart - freeStackEnd);
Serial.printf("BSSL stack used: %d\n-------\n\n", stack_thunk_get_max_usage());
}
void fetchNoConfig() {
Serial.printf(R"EOF(
If there are no CAs or insecure options specified, BearSSL will not connect.
Expect the following call to fail as none have been configured.
)EOF");
BearSSL::WiFiClientSecure client;
fetchURL(&client, gitlab_host, gitlab_port, path);
}
void fetchInsecure() {
Serial.printf(R"EOF(
This is absolutely *insecure*, but you can tell BearSSL not to check the
certificate of the server. In this mode it will accept ANY certificate,
which is subject to man-in-the-middle (MITM) attacks.
)EOF");
BearSSL::WiFiClientSecure client;
client.setInsecure();
fetchURL(&client, gitlab_host, gitlab_port, path);
}
void fetchFingerprint() {
Serial.printf(R"EOF(
The SHA-1 fingerprint of an X.509 certificate can be used to validate it
instead of the while certificate. This is not nearly as secure as real
X.509 validation, but is better than nothing. Also be aware that these
fingerprints will change if anything changes in the certificate chain
(i.e. re-generating the certificate for a new end date, any updates to
the root authorities, etc.).
)EOF");
BearSSL::WiFiClientSecure client;
client.setFingerprint(fingerprint_sni_cloudflaressl_com);
fetchURL(&client, gitlab_host, gitlab_port, path);
}
void fetchSelfSigned() {
Serial.printf(R"EOF(
It is also possible to accept *any* self-signed certificate. This is
absolutely insecure as anyone can make a self-signed certificate.
)EOF");
BearSSL::WiFiClientSecure client;
Serial.printf("First, try and connect to a badssl.com self-signed website (will fail):\n");
fetchURL(&client, "self-signed.badssl.com", 443, "/");
Serial.printf("Now we'll enable self-signed certs (will pass)\n");
client.allowSelfSignedCerts();
fetchURL(&client, "self-signed.badssl.com", 443, "/");
}
void fetchKnownKey() {
Serial.printf(R"EOF(
The server certificate can be completely ignored and its public key
hardcoded in your application. This should be secure as the public key
needs to be paired with the private key of the site, which is obviously
private and not shared. A MITM without the private key would not be
able to establish communications.
)EOF");
BearSSL::WiFiClientSecure client;
BearSSL::PublicKey key(pubkey_sni_cloudflaressl_com);
client.setKnownKey(&key);
fetchURL(&client, gitlab_host, gitlab_port, path);
}
void fetchCertAuthority() {
Serial.printf(R"EOF(
A specific certification authority can be passed in and used to validate
a chain of certificates from a given server. These will be validated
using BearSSL's rules, which do NOT include certificate revocation lists.
A specific server's certificate, or your own self-signed root certificate
can also be used. ESP8266 time needs to be valid for checks to pass as
BearSSL does verify the notValidBefore/After fields.
)EOF");
BearSSL::WiFiClientSecure client;
BearSSL::X509List cert(cert_Cloudflare_Inc_ECC_CA_3);
client.setTrustAnchors(&cert);
Serial.printf("Try validating without setting the time (should fail)\n");
fetchURL(&client, gitlab_host, gitlab_port, path);
Serial.printf("Try again after setting NTP time (should pass)\n");
setClock();
fetchURL(&client, gitlab_host, gitlab_port, path);
}
void fetchFaster() {
Serial.printf(R"EOF(
The ciphers used to set up the SSL connection can be configured to
only support faster but less secure ciphers. If you care about security
you won't want to do this. If you need to maximize battery life, these
may make sense
)EOF");
BearSSL::WiFiClientSecure client;
client.setInsecure();
uint32_t now = millis();
fetchURL(&client, gitlab_host, gitlab_port, path);
uint32_t delta = millis() - now;
client.setInsecure();
client.setCiphersLessSecure();
now = millis();
fetchURL(&client, gitlab_host, gitlab_port, path);
uint32_t delta2 = millis() - now;
std::vector<uint16_t> myCustomList = { BR_TLS_RSA_WITH_AES_256_CBC_SHA256, BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, BR_TLS_RSA_WITH_3DES_EDE_CBC_SHA };
client.setInsecure();
client.setCiphers(myCustomList);
now = millis();
fetchURL(&client, gitlab_host, gitlab_port, path);
uint32_t delta3 = millis() - now;
Serial.printf("Using more secure: %dms\nUsing less secure ciphers: %dms\nUsing custom cipher list: %dms\n", delta, delta2, delta3);
}
#define setup forgetMe
#include <../../libraries/ESP8266WiFi/examples/BearSSL_Validation/BearSSL_Validation.ino>
#undef setup
void setup() {
Serial.begin(115200);
@ -198,7 +22,7 @@ void setup() {
Serial.println("\nEthernet\n");
// 1. Currently when no default is set, esp8266-Arduino uses the first
// 1. Currently when no default route is set, esp8266-Arduino uses the first
// DHCP client interface receiving a valid address and gateway to
// become the new lwIP default interface.
// 2. Otherwise - when using static addresses - lwIP for every packets by
@ -231,8 +55,3 @@ void setup() {
fetchCertAuthority();
fetchFaster();
}
void loop() {
// Nothing to do here
}