Hi,
On 11/07/2020 11:36, Arne Schwabe wrote:
> From: Fabian Knittel <fabian.knit...@lettink.de>
>
> This patch introduces the concept of a return value file for the
> client-connect
> handlers. (This is very similar to the auth value file used during deferred
> authentication.) The file name is stored in the client_connect_state struct.
>
> In addition, the patch also allows the storage of the client config file name
> in struct client_connect_state.
>
> Both changes are used by the client-connect script handler to support deferred
> client-connection handling. The deferred return value file
> (deferred_ret_file)
> is passed to the actual script via the environment. If the script succeeds
> and
> writes the value for deferral into the deferred_ret_file, the handler knows to
> indicate deferral. Later on, the deferred handler checks whether the value of
> the deferred_ret_file has been updated to success or failure.
>
> Signed-off-by: Fabian Knittel <fabian.knit...@lettink.de>
> Signed-off-by: Arne Schwabe <a...@rfc2549.org>
> ---
> src/openvpn/multi.c | 230 +++++++++++++++++++++++++++++++++++++++++---
> src/openvpn/multi.h | 12 +++
> 2 files changed, 227 insertions(+), 15 deletions(-)
>
> diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c
> index ce73f8a1..271d09d8 100644
> --- a/src/openvpn/multi.c
> +++ b/src/openvpn/multi.c
> @@ -1843,6 +1843,168 @@ multi_client_set_protocol_options(struct context *c)
> }
> }
>
> +/**
> + * Delete the temporary file for the return value of client connect
> + * It also removes it from it from client_connect_defer_state and
> + * environment
> + */
> +static void
> +ccs_delete_deferred_ret_file(struct multi_instance *mi)
> +{
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
> + if (ccs->deferred_ret_file)
> + {
> + setenv_del(mi->context.c2.es, "client_connect_deferred_file");
> + if (!platform_unlink(ccs->deferred_ret_file))
> + {
> + msg(D_MULTI_ERRORS, "MULTI: problem deleting temporary file: %s",
> + ccs->deferred_ret_file);
> + }
> + free(ccs->deferred_ret_file);
> + ccs->deferred_ret_file = NULL;
> + }
> +}
> +
> +/**
> + * Create a temporary file for the return value of client connect
> + * and puts it into the client_connect_defer_state and environment
> + * as "client_connect_deferred_file"
> + *
> + * @return boolean value if creation was successfull
> + */
> +static bool
> +ccs_gen_deferred_ret_file(struct multi_instance *mi)
> +{
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
> + struct gc_arena gc = gc_new();
> + const char *fn;
> +
> + if (ccs->deferred_ret_file)
> + {
> + ccs_delete_deferred_ret_file(mi);
> + }
> +
> + fn = platform_create_temp_file(mi->context.options.tmp_dir, "ccr", &gc);
> + if (!fn)
> + {
> + gc_free(&gc);
> + return false;
> + }
> + ccs->deferred_ret_file = string_alloc(fn, NULL);
> +
> + setenv_str(mi->context.c2.es, "client_connect_deferred_file",
> + ccs->deferred_ret_file);
> +
> + gc_free(&gc);
> + return true;
> +}
> +
> +/**
> + * Tests whether the deferred return value file exists and returns the
> + * contained return value.
> + *
> + * @return CC_RET_SKIPPED if the file does not exist or is empty.
> + * CC_RET_DEFERRED, CC_RET_SUCCEEDED or CC_RET_FAILED depending on
> + * the value stored in the file.
> + */
> +static enum client_connect_return
> +ccs_test_deferred_ret_file(struct multi_instance *mi)
> +{
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
> + enum client_connect_return ret = CC_RET_SKIPPED;
> + FILE *fp = fopen(ccs->deferred_ret_file, "r");
I think we should always add an empty line between the first batch of
variable declarations in a block and any code below.
> + if (fp)
> + {
> + const int c = fgetc(fp);
> + switch (c)
> + {
> + case '0':
> + ret = CC_RET_FAILED;
> + break;
> +
> + case '1':
> + ret = CC_RET_SUCCEEDED;
> + break;
> +
> + case '2':
> + ret = CC_RET_DEFERRED;
> + break;
> +
> + case EOF:
> + if (feof(fp))
> + {
> + ret = CC_RET_SKIPPED;
> + break;
> + }
> +
> + /* Not EOF, but other error fall through to error state */
> + default:
> + /* We received an unknown/unexpected value. Assume failure.
> */
> + msg(M_WARN, "WARNING: Unknown/unexcepted value in deferred"
> + "client-connect resultfile");
> + ret = CC_RET_FAILED;
> + }
> + fclose(fp);
> + }
> + return ret;
> +}
> +
> +/**
> + * Deletes the temporary file for the config directives of the client
> connect
> + * script and removes it into the client_connect_defer_state and environment
> + *
> + */
> +static void
> +ccs_delete_config_file(struct multi_instance *mi)
> +{
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
> + if (ccs->config_file)
> + {
> + setenv_del(mi->context.c2.es, "client_connect_config_file");
> + if (!platform_unlink(ccs->config_file))
> + {
> + msg(D_MULTI_ERRORS, "MULTI: problem deleting temporary file: %s",
> + ccs->config_file);
> + }
> + free(ccs->config_file);
> + ccs->config_file = NULL;
> + }
> +}
> +
> +/**
> + * Create a temporary file for the config directives of the client connect
> + * script and puts it into the client_connect_defer_state and environment
> + * as "client_connect_config_file"
> + *
> + * @return boolean value if creation was successfull
> + */
> +static bool
> +ccs_gen_config_file(struct multi_instance *mi)
> +{
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
> + struct gc_arena gc = gc_new();
> + const char *fn;
> +
> + if (ccs->config_file)
> + {
> + ccs_delete_config_file(mi);
> + }
> +
> + fn = platform_create_temp_file(mi->context.options.tmp_dir, "cc", &gc);
> + if (!fn)
> + {
> + gc_free(&gc);
> + return false;
> + }
> + ccs->config_file = string_alloc(fn, NULL);
> +
> + setenv_str(mi->context.c2.es, "client_connect_config_file",
> + ccs->config_file);
> +
> + gc_free(&gc);
> + return true;
> +}
> +
> static enum client_connect_return
> multi_client_connect_call_plugin_v1(struct multi_context *m,
> struct multi_instance *mi,
> @@ -1933,8 +2095,6 @@ multi_client_connect_call_plugin_v2(struct
> multi_context *m,
> return ret;
> }
>
> -
> -
> /**
> * Runs the --client-connect script if one is defined.
> */
> @@ -1948,48 +2108,88 @@ multi_client_connect_call_script(struct multi_context
> *m,
> ASSERT(mi);
>
> enum client_connect_return ret = CC_RET_SKIPPED;
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
>
> if (mi->context.options.client_connect_script)
> {
> struct argv argv = argv_new();
> struct gc_arena gc = gc_new();
> - const char *dc_file = NULL;
>
> setenv_str(mi->context.c2.es, "script_type", "client-connect");
>
> - dc_file = platform_create_temp_file(mi->context.options.tmp_dir,
> - "cc", &gc);
> - if (!dc_file)
> + if (!ccs_gen_config_file(mi)
> + || !ccs_gen_deferred_ret_file(mi))
> {
> ret = CC_RET_FAILED;
> goto cleanup;
> }
>
> argv_parse_cmd(&argv, mi->context.options.client_connect_script);
> - argv_printf_cat(&argv, "%s", dc_file);
> + argv_printf_cat(&argv, "%s", ccs->config_file);
>
> if (openvpn_run_script(&argv, mi->context.c2.es, 0,
> "--client-connect"))
> {
> - multi_client_connect_post(m, mi, dc_file, option_types_found);
> - ret = CC_RET_SUCCEEDED;
> + if (ccs_test_deferred_ret_file(mi) == CC_RET_DEFERRED)
> + {
> + ret = CC_RET_DEFERRED;
> + }
> + else
> + {
> + multi_client_connect_post(m, mi, ccs->config_file,
> + option_types_found);
> + ret = CC_RET_SUCCEEDED;
> + }
> }
> else
> {
> ret = CC_RET_FAILED;
> }
> -
> - if (!platform_unlink(dc_file))
> +cleanup:
> + if (ret != CC_RET_DEFERRED)
> {
> - msg(D_MULTI_ERRORS, "MULTI: problem deleting temporary file: %s",
> - dc_file);
> + ccs_delete_config_file(mi);
> + ccs_delete_deferred_ret_file(mi);
> }
> -cleanup:
> argv_free(&argv);
> gc_free(&gc);
> }
> return ret;
> }
>
> +static enum client_connect_return
> +multi_client_connect_script_deferred(struct multi_context *m,
> + struct multi_instance *mi,
> + unsigned int *option_types_found)
> +{
> + ASSERT(mi);
> + ASSERT(option_types_found);
> + struct client_connect_defer_state *ccs =
> &(mi->client_connect_defer_state);
parenthesis are not needed
> + enum client_connect_return ret = CC_RET_SKIPPED;
> +
> + ret = ccs_test_deferred_ret_file(mi);
> +
> + if (ret == CC_RET_SKIPPED)
> + {
> + /*
> + * Skipped and deferred are equivalent in this context.
> + * skipped means that the called program has not yet
> + * written a return status implicitly needing more time
> + * while deferred is the explicit notifcation that it
typ0: notification
> + * needs more time
> + */
> + ret = CC_RET_DEFERRED;
The comment above made me wonder..What happens if he client-connect
script will never write to file due to a bug or a crash or anything?
> + }
> +
> + if (ret != CC_RET_DEFERRED)
> + {
> + ccs_delete_deferred_ret_file(mi);
> + multi_client_connect_post(m, mi, ccs->config_file,
> + option_types_found);
> + ccs_delete_config_file(mi);
> + }
> + return ret;
> +}
> +
> /**
> * Generates the data channel keys
> */
> @@ -2251,7 +2451,7 @@ static const struct client_connect_handlers
> client_connect_handlers[] = {
> },
> {
> .main = multi_client_connect_call_script,
> - .deferred = multi_client_connect_fail
> + .deferred = multi_client_connect_script_deferred
> },
> {
> .main = multi_client_connect_mda,
> diff --git a/src/openvpn/multi.h b/src/openvpn/multi.h
> index 11da0209..3ebf6b9f 100644
> --- a/src/openvpn/multi.h
> +++ b/src/openvpn/multi.h
> @@ -73,6 +73,18 @@ struct client_connect_defer_state
> /* Remember which option classes where processed for delayed option
> * handling. */
> unsigned int option_types_found;
> +
> + /**
> + * The temporrary file name that contains the return status of the
typ0: temporary
> + * client-connect script if it exits with defer as status
> + */
> + char *deferred_ret_file;
> +
> + /**
> + * The temporary file name that contains the config directives
> + * returned by the client-connect script
> + */
> + char *config_file;
> };
>
> /**
>
The patch looks good. My only concern is reported above and is not
really about this patch, but about the way the deferred handler is designed.
--
Antonio Quartulli
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