diff --git a/libraries/WiFiClientSecure/examples/WiFiClientShowPeerCredentials/WiFiClientShowPeerCredentials.ino b/libraries/WiFiClientSecure/examples/WiFiClientShowPeerCredentials/WiFiClientShowPeerCredentials.ino new file mode 100644 index 0000000000000000000000000000000000000000..17199e2069775296550047632b4afcfc67e78a26 --- /dev/null +++ b/libraries/WiFiClientSecure/examples/WiFiClientShowPeerCredentials/WiFiClientShowPeerCredentials.ino @@ -0,0 +1,97 @@ +// WiFiClientShowPeerCredentials +// +// Example of a establishing a secure connection and then +// showing the fingerprint of the certificate. This can +// be useful in an IoT setting to know for sure that you +// are connecting to the right server. Especally in +// situations where you cannot hardcode a trusted root +// certificate for long periods of time (as they tend to +// get replaced more often than the lifecycle of IoT +// hardware). +// + +#include +#include +#include + +#ifndef WIFI_NETWORK +#define WIFI_NETWORK "MyWifiNetwork" +#endif + +#ifndef WIFI_PASSWD +#define WIFI_PASSWD "MySecretWifiPassword" +#endif + +#define URL "https://arduino.cc" + +void demo() { + WiFiClientSecure *client = new WiFiClientSecure; + client->setInsecure(); // + + HTTPClient https; + if (!https.begin(*client, URL )) { + Serial.println("HTTPS setup failed"); + return; + }; + + https.setTimeout(5000); + + int httpCode = https.GET(); + if (httpCode != 200) { + Serial.print("Connect failed: "); + Serial.println(https.errorToString(httpCode)); + return; + } + + const mbedtls_x509_crt* peer = client->getPeerCertificate(); + + // Show general output / certificate information + // + char buf[1024]; + int l = mbedtls_x509_crt_info (buf, sizeof(buf), "", peer); + if (l <= 0) { + Serial.println("Peer conversion to printable buffer failed"); + return; + }; + Serial.println(); + Serial.println(buf); + + uint8_t fingerprint_remote[32]; + if (!client->getFingerprintSHA256(fingerprint_remote)) { + Serial.println("Failed to get the fingerprint"); + return; + } + // Fingerprint late 2021 + Serial.println("Expecting Fingerprint (SHA256): 70 CF A4 B7 5D 09 E9 2A 52 A8 B6 85 B5 0B D6 BE 83 47 83 5B 3A 4D 3C 3E 32 30 EC 1D 61 98 D7 0F"); + Serial.print( " Received Fingerprint (SHA256): "); + + for (int i = 0; i < 32; i++) { + Serial.print(fingerprint_remote[i], HEX); + Serial.print(" "); + }; + Serial.println(""); +}; + +void setup() { + Serial.begin(115200); + Serial.println("Started " __FILE__ " build " __DATE__ " " __TIME__); + + WiFi.mode(WIFI_STA); + WiFi.begin(WIFI_NETWORK, WIFI_PASSWD); + + while (WiFi.waitForConnectResult() != WL_CONNECTED) { + Serial.println("Wifi fail - rebooting"); + delay(5000); + ESP.restart(); + } +} + +void loop() { + bool already_tried = false; + if ((millis() < 1000) || already_tried) + return; + already_tried = true; + + // Run the test just once. + demo(); +} diff --git a/libraries/WiFiClientSecure/src/WiFiClientSecure.h b/libraries/WiFiClientSecure/src/WiFiClientSecure.h index 8a30145ef47bb962aa6408962057e31d8bb8d069..f27df2fd29e76e7b30ca84f48ec59ff8b9ddadfd 100644 --- a/libraries/WiFiClientSecure/src/WiFiClientSecure.h +++ b/libraries/WiFiClientSecure/src/WiFiClientSecure.h @@ -31,7 +31,7 @@ protected: sslclient_context *sslclient; int _lastError = 0; - int _peek = -1; + int _peek = -1; int _timeout = 0; bool _use_insecure; const char *_CA_cert; @@ -53,7 +53,7 @@ public: int connect(const char *host, uint16_t port, const char *rootCABuff, const char *cli_cert, const char *cli_key); int connect(IPAddress ip, uint16_t port, const char *pskIdent, const char *psKey); int connect(const char *host, uint16_t port, const char *pskIdent, const char *psKey); - int peek(); + int peek(); size_t write(uint8_t data); size_t write(const uint8_t *buf, size_t size); int available(); @@ -73,7 +73,8 @@ public: bool loadPrivateKey(Stream& stream, size_t size); bool verify(const char* fingerprint, const char* domain_name); void setHandshakeTimeout(unsigned long handshake_timeout); - + const mbedtls_x509_crt* getPeerCertificate() { return mbedtls_ssl_get_peer_cert(&sslclient->ssl_ctx); }; + bool getFingerprintSHA256(uint8_t sha256_result[32]) { return get_peer_fingerprint(sslclient, sha256_result); }; int setTimeout(uint32_t seconds){ return 0; } operator bool() diff --git a/libraries/WiFiClientSecure/src/ssl_client.cpp b/libraries/WiFiClientSecure/src/ssl_client.cpp index d643f43ee1179c4ca2d785c762d2e851c3f96ade..31f839844e4fa9619ed42d78e8646b979cfa381c 100644 --- a/libraries/WiFiClientSecure/src/ssl_client.cpp +++ b/libraries/WiFiClientSecure/src/ssl_client.cpp @@ -418,22 +418,10 @@ bool verify_ssl_fingerprint(sslclient_context *ssl_client, const char* fp, const fingerprint_local[i] = low | (high << 4); } - // Get certificate provided by the peer - const mbedtls_x509_crt* crt = mbedtls_ssl_get_peer_cert(&ssl_client->ssl_ctx); - - if (!crt) - { - log_d("could not fetch peer certificate"); - return false; - } - // Calculate certificate's SHA256 fingerprint uint8_t fingerprint_remote[32]; - mbedtls_sha256_context sha256_ctx; - mbedtls_sha256_init(&sha256_ctx); - mbedtls_sha256_starts(&sha256_ctx, false); - mbedtls_sha256_update(&sha256_ctx, crt->raw.p, crt->raw.len); - mbedtls_sha256_finish(&sha256_ctx, fingerprint_remote); + if(!get_peer_fingerprint(ssl_client, fingerprint_remote)) + return false; // Check if fingerprints match if (memcmp(fingerprint_local, fingerprint_remote, 32)) @@ -449,6 +437,28 @@ bool verify_ssl_fingerprint(sslclient_context *ssl_client, const char* fp, const return true; } +bool get_peer_fingerprint(sslclient_context *ssl_client, uint8_t sha256[32]) +{ + if (!ssl_client) { + log_d("Invalid ssl_client pointer"); + return false; + }; + + const mbedtls_x509_crt* crt = mbedtls_ssl_get_peer_cert(&ssl_client->ssl_ctx); + if (!crt) { + log_d("Failed to get peer cert."); + return false; + }; + + mbedtls_sha256_context sha256_ctx; + mbedtls_sha256_init(&sha256_ctx); + mbedtls_sha256_starts(&sha256_ctx, false); + mbedtls_sha256_update(&sha256_ctx, crt->raw.p, crt->raw.len); + mbedtls_sha256_finish(&sha256_ctx, sha256); + + return true; +} + // Checks if peer certificate has specified domain in CN or SANs bool verify_ssl_dn(sslclient_context *ssl_client, const char* domain_name) { diff --git a/libraries/WiFiClientSecure/src/ssl_client.h b/libraries/WiFiClientSecure/src/ssl_client.h index 5ee662fbcec63c809d221186bdc871351784c9f2..8a4cc502a471a4d06ec22ca15a308d2ac14e106b 100644 --- a/libraries/WiFiClientSecure/src/ssl_client.h +++ b/libraries/WiFiClientSecure/src/ssl_client.h @@ -36,5 +36,5 @@ int send_ssl_data(sslclient_context *ssl_client, const uint8_t *data, size_t len int get_ssl_receive(sslclient_context *ssl_client, uint8_t *data, int length); bool verify_ssl_fingerprint(sslclient_context *ssl_client, const char* fp, const char* domain_name); bool verify_ssl_dn(sslclient_context *ssl_client, const char* domain_name); - +bool get_peer_fingerprint(sslclient_context *ssl_client, uint8_t sha256[32]); #endif