static int authenticate(BDRVSSHState *s, const char *user) { int r, ret; const char *userauthlist; LIBSSH2_AGENT *agent = NULL; struct libssh2_agent_publickey *identity; struct libssh2_agent_publickey *prev_identity = NULL; userauthlist = libssh2_userauth_list(s->session, user, strlen(user)); if (strstr(userauthlist, "publickey") == NULL) { ret = -EPERM; error_report("remote server does not support \"publickey\" authentication"); goto out; } /* Connect to ssh-agent and try each identity in turn. */ agent = libssh2_agent_init(s->session); if (!agent) { ret = -EINVAL; session_error_report(s, "failed to initialize ssh-agent support"); goto out; } if (libssh2_agent_connect(agent)) { ret = -ECONNREFUSED; session_error_report(s, "failed to connect to ssh-agent"); goto out; } if (libssh2_agent_list_identities(agent)) { ret = -EINVAL; session_error_report(s, "failed requesting identities from ssh-agent"); goto out; } for(;;) { r = libssh2_agent_get_identity(agent, &identity, prev_identity); if (r == 1) { /* end of list */ break; } if (r < 0) { ret = -EINVAL; session_error_report(s, "failed to obtain identity from ssh-agent"); goto out; } r = libssh2_agent_userauth(agent, user, identity); if (r == 0) { /* Authenticated! */ ret = 0; goto out; } /* Failed to authenticate with this identity, try the next one. */ prev_identity = identity; } ret = -EPERM; error_report("failed to authenticate using publickey authentication " "and the identities held by your ssh-agent"); out: if (agent != NULL) { /* Note: libssh2 implementation implicitly calls * libssh2_agent_disconnect if necessary. */ libssh2_agent_free(agent); } return ret; }