Adding upstream version 1.37.1.upstream/1.37.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 888 insertions, 0 deletions

diff --git a/aclk/aclk_otp.c b/aclk/aclk_otp.c
new file mode 100644
index 0000000..2bdbb70
--- /dev/null
+++ b/aclk/aclk_otp.c
@@ -0,0 +1,888 @@
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "aclk_otp.h"
+#include "aclk_util.h"
+#include "aclk.h"
+
+#include "daemon/common.h"
+
+#include "mqtt_websockets/c-rbuf/include/ringbuffer.h"
+
+static int aclk_https_request(https_req_t *request, https_req_response_t *response) {
+    int rc;
+    // wrapper for ACLK only which loads ACLK specific proxy settings
+    // then only calls https_request
+    struct mqtt_wss_proxy proxy_conf = { .host = NULL, .port = 0, .username = NULL, .password = NULL, .type = MQTT_WSS_DIRECT };
+    aclk_set_proxy((char**)&proxy_conf.host, &proxy_conf.port, &proxy_conf.type);
+
+    if (proxy_conf.type == MQTT_WSS_PROXY_HTTP) {
+        request->proxy_host = (char*)proxy_conf.host; // TODO make it const as well
+        request->proxy_port = proxy_conf.port;
+    }
+
+    rc = https_request(request, response);
+    freez((char*)proxy_conf.host);
+    return rc;
+}
+
+struct auth_data {
+    char *client_id;
+    char *username;
+    char *passwd;
+};
+
+#define PARSE_ENV_JSON_CHK_TYPE(it, type, name)                                                                        \
+    if (json_object_get_type(json_object_iter_peek_value(it)) != type) {                                               \
+        error("value of key \"%s\" should be %s", name, #type);                                                        \
+        goto exit;                                                                                                     \
+    }
+
+#define JSON_KEY_CLIENTID "clientID"
+#define JSON_KEY_USER     "username"
+#define JSON_KEY_PASS     "password"
+#define JSON_KEY_TOPICS   "topics"
+
+static int parse_passwd_response(const char *json_str, struct auth_data *auth) {
+    int rc = 1;
+    json_object *json;
+    struct json_object_iterator it;
+    struct json_object_iterator itEnd;
+
+    json = json_tokener_parse(json_str);
+    if (!json) {
+        error("JSON-C failed to parse the payload of http response of /env endpoint");
+        return 1;
+    }
+
+    it = json_object_iter_begin(json);
+    itEnd = json_object_iter_end(json);
+
+    while (!json_object_iter_equal(&it, &itEnd)) {
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_CLIENTID)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_CLIENTID)
+
+            auth->client_id = strdupz(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_USER)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_USER)
+
+            auth->username = strdupz(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_PASS)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_PASS)
+
+            auth->passwd = strdupz(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_TOPICS)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_array, JSON_KEY_TOPICS)
+
+            if (aclk_generate_topic_cache(json_object_iter_peek_value(&it))) {
+                error("Failed to generate topic cache!");
+                goto exit;
+            }
+            json_object_iter_next(&it);
+            continue;
+        }
+        error("Unknown key \"%s\" in passwd response payload. Ignoring", json_object_iter_peek_name(&it));
+        json_object_iter_next(&it);
+    }
+
+    if (!auth->client_id) {
+        error(JSON_KEY_CLIENTID " is compulsory key in /password response");
+        goto exit;
+    }
+    if (!auth->passwd) {
+        error(JSON_KEY_PASS " is compulsory in /password response");
+        goto exit;
+    }
+    if (!auth->username) {
+        error(JSON_KEY_USER " is compulsory in /password response");
+        goto exit;
+    }
+
+    rc = 0;
+exit:
+    json_object_put(json);
+    return rc;
+}
+
+#define JSON_KEY_ERTRY   "errorNonRetryable"
+#define JSON_KEY_EDELAY  "errorRetryDelaySeconds"
+#define JSON_KEY_EEC     "errorCode"
+#define JSON_KEY_EMSGKEY "errorMsgKey"
+#define JSON_KEY_EMSG    "errorMessage"
+#if JSON_C_MINOR_VERSION >= 13
+static const char *get_json_str_by_path(json_object *json, const char *path) {
+    json_object *ptr;
+    if (json_pointer_get(json, path, &ptr)) {
+        error("Missing compulsory key \"%s\" in error response", path);
+        return NULL;
+    }
+    if (json_object_get_type(ptr) != json_type_string) {
+        error("Value of Key \"%s\" in error response should be string", path);
+        return NULL;
+    }
+    return json_object_get_string(ptr);
+}
+
+static int aclk_parse_otp_error(const char *json_str) {
+    int rc = 1;
+    json_object *json, *ptr;
+    const char *ec;
+    const char *ek;
+    const char *emsg;
+    int block_retry = -1, backoff = -1;
+
+
+    json = json_tokener_parse(json_str);
+    if (!json) {
+        error("JSON-C failed to parse the payload of http response of /env endpoint");
+        return 1;
+    }
+
+    if ((ec = get_json_str_by_path(json, "/" JSON_KEY_EEC)) == NULL)
+        goto exit;
+
+    if ((ek = get_json_str_by_path(json, "/" JSON_KEY_EMSGKEY)) == NULL)
+        goto exit;
+
+    if ((emsg = get_json_str_by_path(json, "/" JSON_KEY_EMSG)) == NULL)
+        goto exit;
+
+    // optional field
+    if (!json_pointer_get(json, "/" JSON_KEY_ERTRY, &ptr)) {
+        if (json_object_get_type(ptr) != json_type_boolean) {
+            error("Error response Key " "/" JSON_KEY_ERTRY " should be of boolean type");
+            goto exit;
+        }
+        block_retry = json_object_get_boolean(ptr);
+    }
+
+    // optional field
+    if (!json_pointer_get(json, "/" JSON_KEY_EDELAY, &ptr)) {
+        if (json_object_get_type(ptr) != json_type_int) {
+            error("Error response Key " "/" JSON_KEY_EDELAY " should be of integer type");
+            goto exit;
+        }
+        backoff = json_object_get_int(ptr);
+    }
+
+    if (block_retry > 0)
+        aclk_disable_runtime = 1;
+
+    if (backoff > 0)
+        aclk_block_until = now_monotonic_sec() + backoff;
+
+    error("Cloud returned EC=\"%s\", Msg-Key:\"%s\", Msg:\"%s\", BlockRetry:%s, Backoff:%ds (-1 unset by cloud)", ec, ek, emsg, block_retry > 0 ? "true" : "false", backoff);
+    rc = 0;
+exit:
+    json_object_put(json);
+    return rc;
+}
+#else
+static int aclk_parse_otp_error(const char *json_str) {
+    int rc = 1;
+    int block_retry = -1, backoff = -1;
+
+    const char *ec = NULL;
+    const char *ek = NULL;
+    const char *emsg = NULL;
+
+    json_object *json;
+    struct json_object_iterator it;
+    struct json_object_iterator itEnd;
+
+    json = json_tokener_parse(json_str);
+    if (!json) {
+        error("JSON-C failed to parse the payload of http response of /env endpoint");
+        return 1;
+    }
+
+    it = json_object_iter_begin(json);
+    itEnd = json_object_iter_end(json);
+
+    while (!json_object_iter_equal(&it, &itEnd)) {
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_EMSG)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_EMSG)
+
+            emsg = json_object_get_string(json_object_iter_peek_value(&it));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_EMSGKEY)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_EMSGKEY)
+
+            ek = json_object_get_string(json_object_iter_peek_value(&it));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_EEC)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_EEC)
+
+            ec = strdupz(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_EDELAY)) {
+            if (json_object_get_type(json_object_iter_peek_value(&it)) != json_type_int) {
+                error("value of key " JSON_KEY_EDELAY " should be integer");
+                goto exit;
+            }
+
+            backoff = json_object_get_int(json_object_iter_peek_value(&it));
+            json_object_iter_next(&it);
+            continue;
+        }
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_ERTRY)) {
+            if (json_object_get_type(json_object_iter_peek_value(&it)) != json_type_boolean) {
+                error("value of key " JSON_KEY_ERTRY " should be integer");
+                goto exit;
+            }
+
+            block_retry = json_object_get_boolean(json_object_iter_peek_value(&it));
+            json_object_iter_next(&it);
+            continue;
+        }
+        error("Unknown key \"%s\" in error response payload. Ignoring", json_object_iter_peek_name(&it));
+        json_object_iter_next(&it);
+    }
+
+    if (block_retry > 0)
+        aclk_disable_runtime = 1;
+
+    if (backoff > 0)
+        aclk_block_until = now_monotonic_sec() + backoff;
+
+    error("Cloud returned EC=\"%s\", Msg-Key:\"%s\", Msg:\"%s\", BlockRetry:%s, Backoff:%ds (-1 unset by cloud)", ec, ek, emsg, block_retry > 0 ? "true" : "false", backoff);
+    rc = 0;
+exit:
+    json_object_put(json);
+    return rc;
+}
+#endif
+
+#if defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER < OPENSSL_VERSION_110
+static EVP_ENCODE_CTX *EVP_ENCODE_CTX_new(void)
+{
+	EVP_ENCODE_CTX *ctx = OPENSSL_malloc(sizeof(*ctx));
+
+	if (ctx != NULL) {
+		memset(ctx, 0, sizeof(*ctx));
+	}
+	return ctx;
+}
+static void EVP_ENCODE_CTX_free(EVP_ENCODE_CTX *ctx)
+{
+	OPENSSL_free(ctx);
+	return;
+}
+#endif
+
+#define CHALLENGE_LEN 256
+#define CHALLENGE_LEN_BASE64 344
+inline static int base64_decode_helper(unsigned char *out, int *outl, const unsigned char *in, int in_len)
+{
+    unsigned char remaining_data[CHALLENGE_LEN];
+    EVP_ENCODE_CTX *ctx = EVP_ENCODE_CTX_new();
+    EVP_DecodeInit(ctx);
+    EVP_DecodeUpdate(ctx, out, outl, in, in_len);
+    int remainder = 0;
+    EVP_DecodeFinal(ctx, remaining_data, &remainder);
+    EVP_ENCODE_CTX_free(ctx);
+    if (remainder) {
+        error("Unexpected data at EVP_DecodeFinal");
+        return 1;
+    }
+    return 0;
+}
+
+inline static int base64_encode_helper(unsigned char *out, int *outl, const unsigned char *in, int in_len)
+{
+    int len;
+    unsigned char *str = out;
+    EVP_ENCODE_CTX *ctx = EVP_ENCODE_CTX_new();
+    EVP_EncodeInit(ctx);
+    EVP_EncodeUpdate(ctx, str, outl, in, in_len);
+    str += *outl;
+    EVP_EncodeFinal(ctx, str, &len);
+    *outl += len;
+    // if we ever expect longer output than what OpenSSL would pack into single line
+    // we would have to skip the endlines, until then we can just cut the string short
+    str = (unsigned char*)strchr((char*)out, '\n');
+    if (str)
+        *str = 0;
+    EVP_ENCODE_CTX_free(ctx);
+    return 0;
+}
+
+#define OTP_URL_PREFIX "/api/v1/auth/node/"
+int aclk_get_otp_challenge(url_t *target, const char *agent_id, unsigned char **challenge, int *challenge_bytes)
+{
+    int rc = 1;
+    https_req_t req = HTTPS_REQ_T_INITIALIZER;
+    https_req_response_t resp = HTTPS_REQ_RESPONSE_T_INITIALIZER;
+
+    BUFFER *url = buffer_create(strlen(OTP_URL_PREFIX) + UUID_STR_LEN + 20);
+
+    req.host = target->host;
+    req.port = target->port;
+    buffer_sprintf(url, "%s/node/%s/challenge", target->path, agent_id);
+    req.url = (char *)buffer_tostring(url);
+
+    if (aclk_https_request(&req, &resp)) {
+        error ("ACLK_OTP Challenge failed");
+        buffer_free(url);
+        return 1;
+    }
+    if (resp.http_code != 200) {
+        error ("ACLK_OTP Challenge HTTP code not 200 OK (got %d)", resp.http_code);
+        buffer_free(url);
+        if (resp.payload_size)
+            aclk_parse_otp_error(resp.payload);
+        goto cleanup_resp;
+    }
+    buffer_free(url);
+
+    info ("ACLK_OTP Got Challenge from Cloud");
+
+    json_object *json = json_tokener_parse(resp.payload);
+    if (!json) {
+        error ("Couldn't parse HTTP GET challenge payload");
+        goto cleanup_resp;
+    }
+    json_object *challenge_json;
+    if (!json_object_object_get_ex(json, "challenge", &challenge_json)) {
+        error ("No key named \"challenge\" in the returned JSON");
+        goto cleanup_json;
+    }
+    if (!json_object_is_type(challenge_json, json_type_string)) {
+        error ("\"challenge\" is not a string JSON type");
+        goto cleanup_json;
+    }
+    const char *challenge_base64;
+    if (!(challenge_base64 = json_object_get_string(challenge_json))) {
+        error("Failed to extract challenge from JSON object");
+        goto cleanup_json;
+    }
+    if (strlen(challenge_base64) != CHALLENGE_LEN_BASE64) {
+        error("Received Challenge has unexpected length of %zu (expected %d)", strlen(challenge_base64), CHALLENGE_LEN_BASE64);
+        goto cleanup_json;
+    }
+
+    *challenge = mallocz((CHALLENGE_LEN_BASE64 / 4) * 3);
+    base64_decode_helper(*challenge, challenge_bytes, (const unsigned char*)challenge_base64, strlen(challenge_base64));
+    if (*challenge_bytes != CHALLENGE_LEN) {
+        error("Unexpected challenge length of %d instead of %d", *challenge_bytes, CHALLENGE_LEN);
+        freez(*challenge);
+        *challenge = NULL;
+        goto cleanup_json;
+    }
+    rc = 0;
+
+cleanup_json:
+    json_object_put(json);
+cleanup_resp:
+    https_req_response_free(&resp);
+    return rc;
+}
+
+int aclk_send_otp_response(const char *agent_id, const unsigned char *response, int response_bytes, url_t *target, struct auth_data *mqtt_auth)
+{
+    int len;
+    int rc = 1;
+    https_req_t req = HTTPS_REQ_T_INITIALIZER;
+    https_req_response_t resp = HTTPS_REQ_RESPONSE_T_INITIALIZER;
+
+    req.host = target->host;
+    req.port = target->port;
+    req.request_type = HTTP_REQ_POST;
+
+    unsigned char base64[CHALLENGE_LEN_BASE64 + 1];
+    memset(base64, 0, CHALLENGE_LEN_BASE64 + 1);
+
+    base64_encode_helper(base64, &len, response, response_bytes);
+
+    BUFFER *url = buffer_create(strlen(OTP_URL_PREFIX) + UUID_STR_LEN + 20);
+    BUFFER *resp_json = buffer_create(strlen(OTP_URL_PREFIX) + UUID_STR_LEN + 20);
+
+    buffer_sprintf(url, "%s/node/%s/password", target->path, agent_id);
+    buffer_sprintf(resp_json, "{\"response\":\"%s\"}", base64);
+
+    req.url = (char *)buffer_tostring(url);
+    req.payload = (char *)buffer_tostring(resp_json);
+    req.payload_size = strlen(req.payload);
+
+    if (aclk_https_request(&req, &resp)) {
+        error ("ACLK_OTP Password error trying to post result to password");
+        goto cleanup_buffers;
+    }
+    if (resp.http_code != 201) {
+        error ("ACLK_OTP Password HTTP code not 201 Created (got %d)", resp.http_code);
+        if (resp.payload_size)
+            aclk_parse_otp_error(resp.payload);
+        goto cleanup_response;
+    }
+    info ("ACLK_OTP Got Password from Cloud");
+
+    if (parse_passwd_response(resp.payload, mqtt_auth)){
+        error("Error parsing response of password endpoint");
+        goto cleanup_response;
+    }
+
+    rc = 0;
+
+cleanup_response:
+    https_req_response_free(&resp);
+cleanup_buffers:
+    buffer_free(resp_json);
+    buffer_free(url);
+    return rc;
+}
+
+#if OPENSSL_VERSION_NUMBER >= OPENSSL_VERSION_300
+static int private_decrypt(EVP_PKEY *p_key, unsigned char * enc_data, int data_len, unsigned char **decrypted)
+#else
+static int private_decrypt(RSA *p_key, unsigned char * enc_data, int data_len, unsigned char **decrypted)
+#endif
+{
+    int result;
+#if OPENSSL_VERSION_NUMBER >= OPENSSL_VERSION_300
+    size_t outlen = EVP_PKEY_size(p_key);
+    EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new(p_key, NULL);
+    if (!ctx)
+        return 1;
+
+    if (EVP_PKEY_decrypt_init(ctx) <= 0)
+        return 1;
+
+    if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_OAEP_PADDING) <= 0)
+        return 1;
+
+    *decrypted = mallocz(outlen);
+
+    if (EVP_PKEY_decrypt(ctx, *decrypted, &outlen, enc_data, data_len) == 1)
+        result = (int) outlen;
+    else
+        result = -1;
+#else
+    *decrypted = mallocz(RSA_size(p_key));
+    result = RSA_private_decrypt(data_len, enc_data, *decrypted, p_key, RSA_PKCS1_OAEP_PADDING);
+#endif
+    if (result == -1)
+    {
+        char err[512];
+        ERR_error_string_n(ERR_get_error(), err, sizeof(err));
+        error("Decryption of the challenge failed: %s", err);
+    }
+    return result;
+}
+
+#if OPENSSL_VERSION_NUMBER >= OPENSSL_VERSION_300
+int aclk_get_mqtt_otp(EVP_PKEY *p_key, char **mqtt_id, char **mqtt_usr, char **mqtt_pass, url_t *target)
+#else
+int aclk_get_mqtt_otp(RSA *p_key, char **mqtt_id, char **mqtt_usr, char **mqtt_pass, url_t *target)
+#endif
+{
+    unsigned char *challenge = NULL;
+    int challenge_bytes;
+
+    char *agent_id = get_agent_claimid();
+    if (agent_id == NULL) {
+        error("Agent was not claimed - cannot perform challenge/response");
+        return 1;
+    }
+
+    // Get Challenge
+    if (aclk_get_otp_challenge(target, agent_id, &challenge, &challenge_bytes)) {
+        error("Error getting challenge");
+        freez(agent_id);
+        return 1;
+    }
+
+    // Decrypt Challenge / Get response
+    unsigned char *response_plaintext;
+    int response_plaintext_bytes = private_decrypt(p_key, challenge, challenge_bytes, &response_plaintext);
+    if (response_plaintext_bytes < 0) {
+        error ("Couldn't decrypt the challenge received");
+        freez(response_plaintext);
+        freez(challenge);
+        freez(agent_id);
+        return 1;
+    }
+    freez(challenge);
+
+    // Encode and Send Challenge
+    struct auth_data data = { .client_id = NULL, .passwd = NULL, .username = NULL };
+    if (aclk_send_otp_response(agent_id, response_plaintext, response_plaintext_bytes, target, &data)) {
+        error("Error getting response");
+        freez(response_plaintext);
+        freez(agent_id);
+        return 1;
+    }
+
+    *mqtt_pass = data.passwd;
+    *mqtt_usr = data.username;
+    *mqtt_id = data.client_id;
+
+    freez(response_plaintext);
+    freez(agent_id);
+    return 0;
+}
+
+#define JSON_KEY_ENC "encoding"
+#define JSON_KEY_AUTH_ENDPOINT "authEndpoint"
+#define JSON_KEY_TRP "transports"
+#define JSON_KEY_TRP_TYPE "type"
+#define JSON_KEY_TRP_ENDPOINT "endpoint"
+#define JSON_KEY_BACKOFF "backoff"
+#define JSON_KEY_BACKOFF_BASE "base"
+#define JSON_KEY_BACKOFF_MAX "maxSeconds"
+#define JSON_KEY_BACKOFF_MIN "minSeconds"
+#define JSON_KEY_CAPS "capabilities"
+
+static int parse_json_env_transport(json_object *json, aclk_transport_desc_t *trp) {
+    struct json_object_iterator it;
+    struct json_object_iterator itEnd;
+
+    it = json_object_iter_begin(json);
+    itEnd = json_object_iter_end(json);
+
+    while (!json_object_iter_equal(&it, &itEnd)) {
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_TRP_TYPE)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_TRP_TYPE)
+            if (trp->type != ACLK_TRP_UNKNOWN) {
+                error(JSON_KEY_TRP_TYPE " set already");
+                goto exit;
+            }
+            trp->type = aclk_transport_type_t_from_str(json_object_get_string(json_object_iter_peek_value(&it)));
+            if (trp->type == ACLK_TRP_UNKNOWN) {
+                error(JSON_KEY_TRP_TYPE " unknown type \"%s\"", json_object_get_string(json_object_iter_peek_value(&it)));
+                goto exit;
+            }
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_TRP_ENDPOINT)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_TRP_ENDPOINT)
+            if (trp->endpoint) {
+                error(JSON_KEY_TRP_ENDPOINT " set already");
+                goto exit;
+            }
+            trp->endpoint = strdupz(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+        
+        error ("unknown JSON key in dictionary (\"%s\")", json_object_iter_peek_name(&it));
+        json_object_iter_next(&it);
+    }
+
+    if (!trp->endpoint) {
+        error (JSON_KEY_TRP_ENDPOINT " is missing from JSON dictionary");
+        goto exit;
+    }
+
+    if (trp->type == ACLK_TRP_UNKNOWN) {
+        error ("transport type not set");
+        goto exit;
+    }
+
+    return 0;
+
+exit:
+    aclk_transport_desc_t_destroy(trp);
+    return 1;
+}
+
+static int parse_json_env_transports(json_object *json_array, aclk_env_t *env) {
+    aclk_transport_desc_t *trp;
+    json_object *obj;
+
+    if (env->transports) {
+        error("transports have been set already");
+        return 1;
+    }
+
+    env->transport_count = json_object_array_length(json_array);
+
+    env->transports = callocz(env->transport_count , sizeof(aclk_transport_desc_t *));
+
+    for (size_t i = 0; i < env->transport_count; i++) {
+        trp = callocz(1, sizeof(aclk_transport_desc_t));
+        obj = json_object_array_get_idx(json_array, i);
+        if (parse_json_env_transport(obj, trp)) {
+            error("error parsing transport idx %d", (int)i);
+            freez(trp);
+            return 1;
+        }
+        env->transports[i] = trp;
+    }
+
+    return 0;
+}
+
+#define MATCHED_CORRECT  1
+#define MATCHED_ERROR   -1
+#define NOT_MATCHED      0
+static int parse_json_backoff_int(struct json_object_iterator *it, int *out, const char* name, int min, int max) {
+    if (!strcmp(json_object_iter_peek_name(it), name)) {
+        if (json_object_get_type(json_object_iter_peek_value(it)) != json_type_int) {
+            error("Could not parse \"%s\". Not an integer as expected.", name);
+            return MATCHED_ERROR;
+        }
+
+        *out = json_object_get_int(json_object_iter_peek_value(it));
+
+        if (*out < min || *out > max) {
+            error("Value of \"%s\"=%d out of range (%d-%d).", name, *out, min, max);
+            return MATCHED_ERROR;
+        }
+
+        return MATCHED_CORRECT;
+    }
+    return NOT_MATCHED;
+}
+
+static int parse_json_backoff(json_object *json, aclk_backoff_t *backoff) {
+    struct json_object_iterator it;
+    struct json_object_iterator itEnd;
+    int ret;
+
+    it = json_object_iter_begin(json);
+    itEnd = json_object_iter_end(json);
+
+    while (!json_object_iter_equal(&it, &itEnd)) {
+        if ( (ret = parse_json_backoff_int(&it, &backoff->base, JSON_KEY_BACKOFF_BASE, 1, 10)) ) {
+            if (ret == MATCHED_ERROR) {
+                return 1;
+            }
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if ( (ret = parse_json_backoff_int(&it, &backoff->max_s, JSON_KEY_BACKOFF_MAX, 500, INT_MAX)) ) {
+            if (ret == MATCHED_ERROR) {
+                return 1;
+            }
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if ( (ret = parse_json_backoff_int(&it, &backoff->min_s, JSON_KEY_BACKOFF_MIN, 0, INT_MAX)) ) {
+            if (ret == MATCHED_ERROR) {
+                return 1;
+            }
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        error ("unknown JSON key in dictionary (\"%s\")", json_object_iter_peek_name(&it));
+        json_object_iter_next(&it);
+    }
+
+    return 0;
+}
+
+static int parse_json_env_caps(json_object *json, aclk_env_t *env) {
+    json_object *obj;
+    const char *str;
+
+    if (env->capabilities) {
+        error("transports have been set already");
+        return 1;
+    }
+
+    env->capability_count = json_object_array_length(json);
+
+    // empty capabilities list is allowed
+    if (!env->capability_count)
+        return 0;
+
+    env->capabilities = callocz(env->capability_count , sizeof(char *));
+
+    for (size_t i = 0; i < env->capability_count; i++) {
+        obj = json_object_array_get_idx(json, i);
+        if (json_object_get_type(obj) != json_type_string) {
+            error("Capability at index %d not a string!", (int)i);
+            return 1;
+        }
+        str = json_object_get_string(obj);
+        if (!str) {
+            error("Error parsing capabilities");
+            return 1;
+        }
+        env->capabilities[i] = strdupz(str);
+    }
+
+    return 0;
+}
+
+static int parse_json_env(const char *json_str, aclk_env_t *env) {
+    json_object *json;
+    struct json_object_iterator it;
+    struct json_object_iterator itEnd;
+
+    json = json_tokener_parse(json_str);
+    if (!json) {
+        error("JSON-C failed to parse the payload of http response of /env endpoint");
+        return 1;
+    }
+
+    it = json_object_iter_begin(json);
+    itEnd = json_object_iter_end(json);
+
+    while (!json_object_iter_equal(&it, &itEnd)) {
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_AUTH_ENDPOINT)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_AUTH_ENDPOINT)
+            if (env->auth_endpoint) {
+                error("authEndpoint set already");
+                goto exit;
+            }
+            env->auth_endpoint = strdupz(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_ENC)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_string, JSON_KEY_ENC)
+            if (env->encoding != ACLK_ENC_UNKNOWN) {
+                error(JSON_KEY_ENC " set already");
+                goto exit;
+            }
+            env->encoding = aclk_encoding_type_t_from_str(json_object_get_string(json_object_iter_peek_value(&it)));
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_TRP)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_array, JSON_KEY_TRP)
+
+            json_object *now = json_object_iter_peek_value(&it);
+            parse_json_env_transports(now, env);
+
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_BACKOFF)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_object, JSON_KEY_BACKOFF)
+
+            if (parse_json_backoff(json_object_iter_peek_value(&it), &env->backoff)) {
+                env->backoff.base = 0;
+                error("Error parsing Backoff parameters in env");
+                goto exit;
+            }
+
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        if (!strcmp(json_object_iter_peek_name(&it), JSON_KEY_CAPS)) {
+            PARSE_ENV_JSON_CHK_TYPE(&it, json_type_array, JSON_KEY_CAPS)
+
+            if (parse_json_env_caps(json_object_iter_peek_value(&it), env)) {
+                error("Error parsing capabilities list");
+                goto exit;
+            }
+
+            json_object_iter_next(&it);
+            continue;
+        }
+
+        error ("unknown JSON key in dictionary (\"%s\")", json_object_iter_peek_name(&it));
+        json_object_iter_next(&it);
+    }
+
+    // Check all compulsory keys have been set
+    if (env->transport_count < 1) {
+        error("env has to return at least one transport");
+        goto exit;
+    }
+    if (!env->auth_endpoint) {
+        error(JSON_KEY_AUTH_ENDPOINT " is compulsory");
+        goto exit;
+    }
+    if (env->encoding == ACLK_ENC_UNKNOWN) {
+        error(JSON_KEY_ENC " is compulsory");
+        goto exit;
+    }
+    if (!env->backoff.base) {
+        error(JSON_KEY_BACKOFF " is compulsory");
+        goto exit;
+    }
+
+    json_object_put(json);
+    return 0;
+
+exit:
+    aclk_env_t_destroy(env);
+    json_object_put(json);
+    return 1;
+}
+
+int aclk_get_env(aclk_env_t *env, const char* aclk_hostname, int aclk_port) {
+    BUFFER *buf = buffer_create(1024);
+
+    https_req_t req = HTTPS_REQ_T_INITIALIZER;
+    https_req_response_t resp = HTTPS_REQ_RESPONSE_T_INITIALIZER;
+
+    req.request_type = HTTP_REQ_GET;
+
+    char *agent_id = get_agent_claimid();
+    if (agent_id == NULL)
+    {
+        error("Agent was not claimed - cannot perform challenge/response");
+        buffer_free(buf);
+        return 1;
+    }
+
+    buffer_sprintf(buf, "/api/v1/env?v=%s&cap=proto,ctx&claim_id=%s", &(VERSION[1]) /* skip 'v' at beginning */, agent_id);
+
+    freez(agent_id);
+
+    req.host = (char*)aclk_hostname;
+    req.port = aclk_port;
+    req.url = buf->buffer;
+    if (aclk_https_request(&req, &resp)) {
+        error("Error trying to contact env endpoint");
+        https_req_response_free(&resp);
+        buffer_free(buf);
+        return 1;
+    }
+    if (resp.http_code != 200) {
+        error("The HTTP code not 200 OK (Got %d)", resp.http_code);
+        if (resp.payload_size)
+            aclk_parse_otp_error(resp.payload);
+        https_req_response_free(&resp);
+        buffer_free(buf);
+        return 1;
+    }
+
+    if (!resp.payload || !resp.payload_size) {
+        error("Unexpected empty payload as response to /env call");
+        https_req_response_free(&resp);
+        buffer_free(buf);
+        return 1;
+    }
+
+    if (parse_json_env(resp.payload, env)) {
+        error ("error parsing /env message");
+        https_req_response_free(&resp);
+        buffer_free(buf);
+        return 1;
+    }
+
+    info("Getting Cloud /env successful");
+
+    https_req_response_free(&resp);
+    buffer_free(buf);
+    return 0;
+}