Support for mbedtls v2.x

[robin-thoni]

I'm trying to use your library in ESPHome, unfortunately, the mbedtls version included in the Espressif Arduino framework (/data/cache/platformio/packages/framework-arduinoespressif32/tools/sdk/esp32/include/mbedtls/mbedtls) seems to be 2.x, which is not compatible:

src/esphome/components/tesla_ble/client.cpp: In member function 'int TeslaBLE::Client::LoadPrivateKey(const uint8_t*, size_t)':
src/esphome/components/tesla_ble/client.cpp:92:65: error: too many arguments to function 'int mbedtls_pk_parse_key(mbedtls_pk_context*, const unsigned char*, size_t, const unsigned char*, size_t)'
       password, 0, mbedtls_ctr_drbg_random, &this->drbg_context_);
                                                                 ^
In file included from src/esphome/components/tesla_ble/client.h:10,
                 from src/esphome/components/tesla_ble/client.cpp:1:
/data/cache/platformio/packages/framework-arduinoespressif32/tools/sdk/esp32/include/mbedtls/mbedtls/include/mbedtls/pk.h:712:5: note: declared here
 int mbedtls_pk_parse_key( mbedtls_pk_context *ctx,
     ^~~~~~~~~~~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp: In member function 'int TeslaBLE::Client::GeneratePublicKey()':
src/esphome/components/tesla_ble/client.cpp:131:51: error: 'mbedtls_ecp_keypair' {aka 'struct mbedtls_ecp_keypair'} has no member named 'private_grp'
       &mbedtls_pk_ec(this->private_key_context_)->private_grp,
                                                   ^~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:132:51: error: 'mbedtls_ecp_keypair' {aka 'struct mbedtls_ecp_keypair'} has no member named 'private_Q'
       &mbedtls_pk_ec(this->private_key_context_)->private_Q,
                                                   ^~~~~~~~~
src/esphome/components/tesla_ble/client.cpp: In member function 'int TeslaBLE::Client::GenerateKeyId()':
src/esphome/components/tesla_ble/client.cpp:153:54: error: void value not ignored as it ought to be
   int return_code = mbedtls_sha1_starts(&sha1_context);
                                                      ^
src/esphome/components/tesla_ble/client.cpp:160:59: error: void value not ignored as it ought to be
                                     this->public_key_size_);
                                                           ^
src/esphome/components/tesla_ble/client.cpp:167:58: error: void value not ignored as it ought to be
   return_code = mbedtls_sha1_finish(&sha1_context, buffer);
                                                          ^
src/esphome/components/tesla_ble/client.cpp: In member function 'int TeslaBLE::Client::LoadTeslaKey(const uint8_t*, size_t)':
src/esphome/components/tesla_ble/client.cpp:193:62: error: 'mbedtls_ecp_keypair' {aka 'struct mbedtls_ecp_keypair'} has no member named 'private_grp'
   int return_code = mbedtls_ecp_group_load(&this->tesla_key_.private_grp,
                                                              ^~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:201:25: error: 'mbedtls_ecp_keypair' {aka 'struct mbedtls_ecp_keypair'} has no member named 'private_grp'
       &this->tesla_key_.private_grp, &this->tesla_key_.private_Q,
                         ^~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:201:56: error: 'mbedtls_ecp_keypair' {aka 'struct mbedtls_ecp_keypair'} has no member named 'private_Q'
       &this->tesla_key_.private_grp, &this->tesla_key_.private_Q,
                                                        ^~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:241:50: error: void value not ignored as it ought to be
   return_code = mbedtls_sha1_starts(&sha1_context);
                                                  ^
src/esphome/components/tesla_ble/client.cpp:248:62: error: void value not ignored as it ought to be
                                     temp_shared_secret_length);
                                                              ^
src/esphome/components/tesla_ble/client.cpp:254:72: error: void value not ignored as it ought to be
   return_code = mbedtls_sha1_finish(&sha1_context, this->shared_secret_);
                                                                        ^
src/esphome/components/tesla_ble/client.cpp: In member function 'int TeslaBLE::Client::Encrypt(unsigned char*, size_t, unsigned char*, size_t, size_t*, unsigned char*)':
src/esphome/components/tesla_ble/client.cpp:297:49: error: too few arguments to function 'int mbedtls_gcm_starts(mbedtls_gcm_context*, int, const unsigned char*, size_t, const unsigned char*, size_t)'
                                    sizeof(nonce));
                                                 ^
In file included from src/esphome/components/tesla_ble/client.cpp:7:
/data/cache/platformio/packages/framework-arduinoespressif32/tools/sdk/esp32/include/mbedtls/mbedtls/include/mbedtls/gcm.h:244:5: note: declared here
 int mbedtls_gcm_starts( mbedtls_gcm_context *ctx,
     ^~~~~~~~~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:304:40: error: invalid conversion from 'unsigned char*' to 'size_t' {aka 'unsigned int'} [-fpermissive]
       mbedtls_gcm_update(&aes_context, input_buffer, input_buffer_length,
                                        ^~~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:304:54: error: invalid conversion from 'size_t' {aka 'unsigned int'} to 'const unsigned char*' [-fpermissive]
       mbedtls_gcm_update(&aes_context, input_buffer, input_buffer_length,
                                                      ^~~~~~~~~~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:305:76: error: too many arguments to function 'int mbedtls_gcm_update(mbedtls_gcm_context*, size_t, const unsigned char*, unsigned char*)'
                          output_buffer, output_buffer_length, output_length);
                                                                            ^
In file included from src/esphome/components/tesla_ble/client.cpp:7:
/data/cache/platformio/packages/framework-arduinoespressif32/tools/sdk/esp32/include/mbedtls/mbedtls/include/mbedtls/gcm.h:276:5: note: declared here
 int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
     ^~~~~~~~~~~~~~~~~~
src/esphome/components/tesla_ble/client.cpp:317:69: error: too many arguments to function 'int mbedtls_gcm_finish(mbedtls_gcm_context*, unsigned char*, size_t)'
                          &finish_buffer_length, signature_buffer, 16);
                                                                     ^
In file included from src/esphome/components/tesla_ble/client.cpp:7:
/data/cache/platformio/packages/framework-arduinoespressif32/tools/sdk/esp32/include/mbedtls/mbedtls/include/mbedtls/gcm.h:297:5: note: declared here
 int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
     ^~~~~~~~~~~~~~~~~~
*** [.pioenvs/watchy-01/src/esphome/components/tesla_ble/client.cpp.o] Error 1

I quickly had a look at it, but some changes do not seem that trivial to me. Any chance you could make the library compatible with both versions (2.x and 3.x)? I doubt adding 3.x on top of 2.x in my work tree would do any good.

Thanks!

[MrBLJ]

@robin-thoni sorry to hijack your thread, but did you manage to fix your issue ? With the recent limitation imposed by Tesla on the number of command we can send using the API each day, BLE support would be most welcome.

[robin-thoni]

I managed to make it build inside ESPHome w/ a few tweaks, however, the ESP never bothered to connect to the car, so I'm not sure my mod is correct :/

[MrBLJ]

I managed to make it build inside ESPHome w/ a few tweaks, however, the ESP never bothered to connect to the car, so I'm not sure my mod is correct :/

Thanks a lot for you reply. Would you mind sharing your work ?

[robin-thoni]

Here it is: https://github.com/robin-thoni/tesla-ble-esphome

[MrBLJ]

Here it is: https://github.com/robin-thoni/tesla-ble-esphome

Thanks a lot. Would it be possible to describe what you achieved, and the issues that you faced ?

[robin-thoni]

• I imported a local version of nanopb. Would be nice to use it from PIO registry instead.
• I fixed the imports to be relative to module
• Finally, I tried to downgrade mbedtls to 2.x. It builds, but it's not tested, due to the blocker below.

The current blocker is that the ESP doesn't want to connect to the car, for some reason, it's like it's ignoring it. I didn't do much test yet to understand why.

[robin-thoni]

Closing since I got it working: https://github.com/esphome/feature-requests/issues/2630#issuecomment-2210962105