diff options
Diffstat (limited to 'src/client.c')
| -rw-r--r-- | src/client.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/src/client.c b/src/client.c new file mode 100644 index 0000000..64df1eb --- /dev/null +++ b/src/client.c @@ -0,0 +1,187 @@ +#include <libssh/callbacks.h> +#include <stdio.h> +#include <stdlib.h> + +#include "../config.h" +#include "client.h" + +// callback function for channel data and exceptions +static int client_data_function(ssh_session session, ssh_channel channel, void *data, + uint32_t len, int is_stderr, void *userdata) { + struct client_channel_data_struct *cdata = (struct client_channel_data_struct *) userdata; + (void) session; + (void) channel; + (void) is_stderr; + + if (ssh_channel_is_open(cdata->proxy_channel)) + return ssh_channel_write(cdata->proxy_channel, (char*) data, len); + else + return SSH_ERROR; +} + +static void client_channel_eof_callback (ssh_session session, ssh_channel channel, void *userdata) +{ + struct client_channel_data_struct *cdata = (struct client_channel_data_struct *) userdata; + (void) session; + (void) channel; + + if (ssh_channel_is_open(cdata->proxy_channel)) + ssh_channel_send_eof(cdata->proxy_channel); +} + +static void client_channel_close_callback (ssh_session session, ssh_channel channel, void *userdata) +{ + struct client_channel_data_struct *cdata = (struct client_channel_data_struct *) userdata; + (void) session; + (void) channel; + + if (ssh_channel_is_open(cdata->proxy_channel)) + ssh_channel_close(cdata->proxy_channel); +} + +static void client_channel_exit_status_callback (ssh_session session, ssh_channel channel, int exit_status, void *userdata) +{ + (void) session; + (void) channel; + (void) userdata; + printf("client exit status callback %d\n", exit_status); +} + +static void client_channel_signal_callback (ssh_session session, ssh_channel channel, + const char *signal, void *userdata) { + (void) session; + (void) channel; + (void) signal; + (void) userdata; + printf("client signal callback\n"); +} + +static void client_channel_exit_signal_callback (ssh_session session, ssh_channel channel, + const char *signal, int core, const char *errmsg, + const char *lang, void *userdata) { + (void) session; + (void) channel; + (void) signal; + (void) core; + (void) errmsg; + (void) lang; + (void) userdata; + printf("client exit signal callback\n"); +} + +struct client_channel_data_struct* client_dial(ssh_event event, struct proxy_channel_data_struct *pdata, const char * hostname) +{ + struct client_channel_data_struct *cdata = malloc(sizeof(*cdata)); + cdata->event = event; + cdata->my_session = NULL; + cdata->my_channel = NULL; + cdata->proxy_channel = pdata->my_channel; + cdata->client_channel_cb = NULL; + + /* First we try to add the private key that the server will accept */ + ssh_key privkey; + if (ssh_pki_import_privkey_file(PRIVKEY_PATH, NULL, NULL, NULL, &privkey) != SSH_OK) { + printf("Error importing private key"); + goto privkey_clean; + } + + /* We try to connect to the remote server */ + printf("Connecting to %s\n", hostname); + cdata->my_session = ssh_new(); + + ssh_options_set(cdata->my_session, SSH_OPTIONS_HOST, hostname); + ssh_options_set(cdata->my_session, SSH_OPTIONS_USER, USER_TO_LOGIN_AS); + int verbosity = SSH_LOG_PROTOCOL; + ssh_options_set(cdata->my_session, SSH_OPTIONS_LOG_VERBOSITY, &verbosity); + + if (ssh_connect(cdata->my_session) != SSH_OK) { + printf("Error connecting to %s: %s\n", hostname, ssh_get_error(cdata->my_session)); + goto session_clean; + } + + /* We now validate the remote server's public key */ + ssh_key server_pub_key; + unsigned char * hash = NULL; + size_t hlen; + char * hexa = NULL; + if (ssh_get_server_publickey(cdata->my_session, &server_pub_key) != SSH_OK) { + fprintf(stderr, "Error getting server publickey: %s\n", ssh_get_error(cdata->my_session)); + goto pubkey_clean; + } + if (ssh_get_publickey_hash(server_pub_key, SSH_PUBLICKEY_HASH_SHA1, &hash, &hlen) != SSH_OK) { + fprintf(stderr, "Error getting publickey hash: %s\n", ssh_get_error(cdata->my_session)); + goto pubkey_hash_clean; + } + hexa = ssh_get_hexa(hash, hlen); + printf("Server public key hash : %s\n", hexa); // TODO validate the key + // if error goto pubkey_nomatch_clean + + /* With the server checked, we can authenticate */ + if(ssh_userauth_publickey(cdata->my_session, NULL, privkey) == SSH_AUTH_SUCCESS){ + printf("Authentication success\n"); + } else { + printf("Error private key was rejected\n"); + goto auth_clean; + } + + /* we open the client channel */ + cdata->my_channel = ssh_channel_new(cdata->my_session); + if (cdata->my_channel == NULL) { + printf("Couldn't open client channel to %s\n", hostname); + goto channel_clean; + } + + /* we open a session channel for the future shell, not suitable for tcp + * forwarding */ + if (ssh_channel_open_session(cdata->my_channel) != SSH_OK) { + printf("Couldn't open the session channel\n"); + goto channel_clean; + } + + cdata->client_channel_cb = malloc(sizeof(*cdata->client_channel_cb)); + cdata->client_channel_cb->userdata = cdata; + cdata->client_channel_cb->channel_data_function = client_data_function; + cdata->client_channel_cb->channel_eof_function = client_channel_eof_callback; + cdata->client_channel_cb->channel_close_function = client_channel_close_callback; + cdata->client_channel_cb->channel_exit_status_function = client_channel_exit_status_callback; + cdata->client_channel_cb->channel_signal_function = client_channel_signal_callback; + cdata->client_channel_cb->channel_exit_signal_function = client_channel_exit_signal_callback; + + ssh_callbacks_init(cdata->client_channel_cb); + ssh_set_channel_callbacks(cdata->my_channel, cdata->client_channel_cb); + ssh_event_add_session(event, cdata->my_session); + + ssh_string_free_char(hexa); + ssh_clean_pubkey_hash(&hash); + ssh_key_free(server_pub_key); + ssh_key_free(privkey); + return cdata; + +channel_clean: + ssh_channel_free(cdata->my_channel); +auth_clean: + // TODO +//pubkey_nomatch_clean: + ssh_string_free_char(hexa); +pubkey_hash_clean: + ssh_clean_pubkey_hash(&hash); +pubkey_clean: + ssh_key_free(server_pub_key); +session_clean: + ssh_disconnect(cdata->my_session); + ssh_free(cdata->my_session); +privkey_clean: + ssh_key_free(privkey); + free(cdata); + return NULL; +} + +void client_cleanup(struct client_channel_data_struct *cdata) +{ + ssh_event_remove_session(cdata->event, cdata->my_session); + ssh_channel_free(cdata->my_channel); + ssh_disconnect(cdata->my_session); + ssh_free(cdata->my_session); + free(cdata->client_channel_cb); + free(cdata); +} |