/*
This file is part of TALER
(C) 2014 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with
TALER; see the file COPYING. If not, If not, see
*/
/**
* @file taler-mint-httpd_parsing.c
* @brief functions to parse incoming requests (MHD arguments and JSON snippets)
* @author Florian Dold
* @author Benedikt Mueller
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include "taler-mint-httpd_parsing.h"
#include "taler-mint-httpd_responses.h"
/**
* Initial size for POST
* request buffer.
*/
#define REQUEST_BUFFER_INITIAL 1024
/**
* Maximum POST request size
*/
#define REQUEST_BUFFER_MAX (1024*1024)
/**
* Buffer for POST requests.
*/
struct Buffer
{
/**
* Allocated memory
*/
char *data;
/**
* Number of valid bytes in buffer.
*/
size_t fill;
/**
* Number of allocated bytes in buffer.
*/
size_t alloc;
};
/**
* Initialize a buffer.
*
* @param buf the buffer to initialize
* @param data the initial data
* @param data_size size of the initial data
* @param alloc_size size of the buffer
* @param max_size maximum size that the buffer can grow to
* @return a GNUnet result code
*/
static int
buffer_init (struct Buffer *buf,
const void *data,
size_t data_size,
size_t alloc_size,
size_t max_size)
{
if (data_size > max_size || alloc_size > max_size)
return GNUNET_SYSERR;
if (data_size > alloc_size)
alloc_size = data_size;
buf->data = GNUNET_malloc (alloc_size);
memcpy (buf->data, data, data_size);
return GNUNET_OK;
}
/**
* Free the data in a buffer. Does *not* free
* the buffer object itself.
*
* @param buf buffer to de-initialize
*/
static void
buffer_deinit (struct Buffer *buf)
{
GNUNET_free (buf->data);
buf->data = NULL;
}
/**
* Append data to a buffer, growing the buffer if necessary.
*
* @param buf the buffer to append to
* @param data the data to append
* @param size the size of @a data
* @param max_size maximum size that the buffer can grow to
* @return GNUNET_OK on success,
* GNUNET_NO if the buffer can't accomodate for the new data
*/
static int
buffer_append (struct Buffer *buf,
const void *data,
size_t data_size,
size_t max_size)
{
if (buf->fill + data_size > max_size)
return GNUNET_NO;
if (data_size + buf->fill > buf->alloc)
{
char *new_buf;
size_t new_size = buf->alloc;
while (new_size < buf->fill + data_size)
new_size += 2;
if (new_size > max_size)
return GNUNET_NO;
new_buf = GNUNET_malloc (new_size);
memcpy (new_buf, buf->data, buf->fill);
buf->data = new_buf;
buf->alloc = new_size;
}
memcpy (buf->data + buf->fill, data, data_size);
buf->fill += data_size;
return GNUNET_OK;
}
/**
* Process a POST request containing a JSON object. This
* function realizes an MHD POST processor that will
* (incrementally) process JSON data uploaded to the HTTP
* server. It will store the required state in the
* "connection_cls", which must be cleaned up using
* #TALER_MINT_parse_post_cleanup_callback().
*
* @param connection the MHD connection
* @param con_cs the closure (points to a `struct Buffer *`)
* @param upload_data the POST data
* @param upload_data_size number of bytes in @a upload_data
* @param json the JSON object for a completed request
* @returns
* GNUNET_YES if json object was parsed or at least
* may be parsed in the future (call again);
* `*json` will be NULL if we need to be called again,
* and non-NULL if we are done.
* GNUNET_NO is request incomplete or invalid
* (error message was generated)
* GNUNET_SYSERR on internal error
* (we could not even queue an error message,
* close HTTP session with MHD_NO)
*/
int
TALER_MINT_parse_post_json (struct MHD_Connection *connection,
void **con_cls,
const char *upload_data,
size_t *upload_data_size,
json_t **json)
{
struct Buffer *r = *con_cls;
*json = NULL;
if (NULL == *con_cls)
{
/* We are seeing a fresh POST request. */
r = GNUNET_new (struct Buffer);
if (GNUNET_OK !=
buffer_init (r,
upload_data,
*upload_data_size,
REQUEST_BUFFER_INITIAL,
REQUEST_BUFFER_MAX))
{
*con_cls = NULL;
buffer_deinit (r);
GNUNET_free (r);
return (MHD_NO ==
TALER_MINT_reply_internal_error (connection,
"out of memory"))
? GNUNET_SYSERR : GNUNET_NO;
}
/* everything OK, wait for more POST data */
*upload_data_size = 0;
*con_cls = r;
return GNUNET_YES;
}
if (0 != *upload_data_size)
{
/* We are seeing an old request with more data available. */
if (GNUNET_OK !=
buffer_append (r,
upload_data,
*upload_data_size,
REQUEST_BUFFER_MAX))
{
/* Request too long */
*con_cls = NULL;
buffer_deinit (r);
GNUNET_free (r);
return (MHD_NO ==
TALER_MINT_reply_request_too_large (connection))
? GNUNET_SYSERR : GNUNET_NO;
}
/* everything OK, wait for more POST data */
*upload_data_size = 0;
return GNUNET_YES;
}
/* We have seen the whole request. */
*json = json_loadb (r->data,
r->fill,
0,
NULL);
buffer_deinit (r);
GNUNET_free (r);
if (NULL == *json)
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Failed to parse JSON request body\n");
return (MHD_YES ==
TALER_MINT_reply_invalid_json (connection))
? GNUNET_NO : GNUNET_SYSERR;
}
*con_cls = NULL;
return GNUNET_YES;
}
/**
* Function called whenever we are done with a request
* to clean up our state.
*
* @param con_cls value as it was left by
* #TALER_MINT_parse_post_json(), to be cleaned up
*/
void
TALER_MINT_parse_post_cleanup_callback (void *con_cls)
{
struct Buffer *r = con_cls;
if (NULL != r)
buffer_deinit (r);
}
/**
* Navigate through a JSON tree.
*
* Sends an error response if navigation is impossible (i.e.
* the JSON object is invalid)
*
* @param connection the connection to send an error response to
* @param root the JSON node to start the navigation at.
* @param ... navigation specification (see `enum TALER_MINT_JsonNavigationCommand`)
* @return
* #GNUNET_YES if navigation was successful
* #GNUNET_NO if json is malformed, error response was generated
* #GNUNET_SYSERR on internal error (no response was generated,
* connection must be closed)
*/
int
GNUNET_MINT_parse_navigate_json (struct MHD_Connection *connection,
const json_t *root,
...)
{
va_list argp;
int ret;
json_t *path; /* what's our current path from 'root'? */
path = json_array ();
va_start (argp, root);
ret = 2; /* just not any of the valid return values */
while (2 == ret)
{
enum TALER_MINT_JsonNavigationCommand command
= va_arg (argp,
enum TALER_MINT_JsonNavigationCommand);
switch (command)
{
case JNAV_FIELD:
{
const char *fname = va_arg(argp, const char *);
json_array_append_new (path,
json_string (fname));
root = json_object_get (root,
fname);
if (NULL == root)
{
ret = (MHD_YES ==
TALER_MINT_reply_json_pack (connection,
MHD_HTTP_BAD_REQUEST,
"{s:s, s:s, s:o}",
"error",
"missing field in JSON",
"field",
fname,
"path",
path))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
}
break;
case JNAV_INDEX:
{
int fnum = va_arg(argp, int);
json_array_append_new (path,
json_integer (fnum));
root = json_array_get (root,
fnum);
if (NULL == root)
{
ret = (MHD_YES ==
TALER_MINT_reply_json_pack (connection,
MHD_HTTP_BAD_REQUEST,
"{s:s, s:o}",
"error",
"missing index in JSON",
"path", path))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
}
break;
case JNAV_RET_DATA:
{
void *where = va_arg (argp, void *);
size_t len = va_arg (argp, size_t);
const char *str;
int res;
str = json_string_value (root);
if (NULL == str)
{
ret = (MHD_YES ==
TALER_MINT_reply_json_pack (connection,
MHD_HTTP_BAD_REQUEST,
"{s:s, s:o}",
"error",
"string expected",
"path",
path))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
res = GNUNET_STRINGS_string_to_data (str, strlen (str),
where, len);
if (GNUNET_OK != res)
{
ret = (MHD_YES ==
TALER_MINT_reply_json_pack (connection,
MHD_HTTP_BAD_REQUEST,
"{s:s, s:o}",
"error",
"malformed binary data in JSON",
"path",
path))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
ret = GNUNET_OK;
}
break;
case JNAV_RET_DATA_VAR:
{
void **where = va_arg (argp, void **);
size_t *len = va_arg (argp, size_t *);
const char *str;
str = json_string_value (root);
if (NULL == str)
{
ret = (MHD_YES ==
TALER_MINT_reply_internal_error (connection,
"json_string_value() failed"))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
*len = (strlen (str) * 5) / 8;
if (NULL != where)
{
int res;
*where = GNUNET_malloc (*len);
res = GNUNET_STRINGS_string_to_data (str,
strlen (str),
*where,
*len);
if (GNUNET_OK != res)
{
GNUNET_free (*where);
*where = NULL;
*len = 0;
ret = (MHD_YES ==
TALER_MINT_reply_json_pack (connection,
MHD_HTTP_BAD_REQUEST,
"{s:s, s:o}",
"error",
"malformed binary data in JSON",
"path", path))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
}
ret = GNUNET_OK;
}
break;
case JNAV_RET_TYPED_JSON:
{
int typ = va_arg (argp, int);
const json_t **r_json = va_arg (argp, const json_t **);
if ( (-1 != typ) && (json_typeof (root) != typ))
{
ret = (MHD_YES ==
TALER_MINT_reply_json_pack (connection,
MHD_HTTP_BAD_REQUEST,
"{s:s, s:i, s:i, s:o}",
"error", "wrong JSON field type",
"type_expected", typ,
"type_actual", json_typeof (root),
"path", path))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
*r_json = root;
ret = GNUNET_OK;
}
break;
default:
GNUNET_break (0);
ret = (MHD_YES ==
TALER_MINT_reply_internal_error (connection,
"unhandled value in switch"))
? GNUNET_NO : GNUNET_SYSERR;
break;
}
}
va_end (argp);
json_decref (path);
return ret;
}
/**
* Find a fixed-size field in the top-level of the JSON tree and store
* it in @a data.
*
* Sends an error response if navigation is impossible (i.e.
* the JSON object is invalid)
*
* @param connection the connection to send an error response to
* @param root the JSON node to start the navigation at.
* @param field name of the field to navigate to
* @param data where to store the extracted data
* @param data_size size of the @a data field
* @param[IN|OUT] ret return value, function does nothing if @a ret is not #GNUNET_YES
* on entry; will set @a ret to:
* #GNUNET_YES if navigation was successful
* #GNUNET_NO if json is malformed, error response was generated
* #GNUNET_SYSERR on internal error
*/
static void
parse_fixed_json_data (struct MHD_Connection *connection,
const json_t *root,
const char *field,
void *data,
size_t data_size,
int *ret)
{
if (GNUNET_YES != *ret)
return;
*ret = GNUNET_MINT_parse_navigate_json (connection,
root,
JNAV_FIELD, field,
JNAV_RET_DATA, data, data_size);
}
/**
* Find a variable-size field in the top-level of the JSON tree and store
* it in @a data.
*
* Sends an error response if navigation is impossible (i.e.
* the JSON object is invalid)
*
* @param connection the connection to send an error response to
* @param root the JSON node to start the navigation at.
* @param field name of the field to navigate to
* @param data where to store a pointer to memory allocated for the extracted data
* @param[IN|OUT] ret return value, function does nothing if @a ret is not #GNUNET_YES
* on entry; will set @a ret to:
* #GNUNET_YES if navigation was successful
* #GNUNET_NO if json is malformed, error response was generated
* #GNUNET_SYSERR on internal error
*/
static void
parse_variable_json_data (struct MHD_Connection *connection,
const json_t *root,
const char *field,
void **data,
size_t *data_size,
int *ret)
{
if (GNUNET_YES != *ret)
return;
*ret = GNUNET_MINT_parse_navigate_json (connection,
root,
JNAV_FIELD, field,
JNAV_RET_DATA_VAR, data, data_size);
}
/**
* Parse JSON object into components based on the given field
* specification.
*
* @param connection the connection to send an error response to
* @param root the JSON node to start the navigation at.
* @param spec field specification for the parser
* @return
* #GNUNET_YES if navigation was successful (caller is responsible
* for freeing allocated variable-size data using
* #TALER_MINT_release_parsed_data() when done)
* #GNUNET_NO if json is malformed, error response was generated
* #GNUNET_SYSERR on internal error
*/
int
TALER_MINT_parse_json_data (struct MHD_Connection *connection,
const json_t *root,
struct GNUNET_MINT_ParseFieldSpec *spec)
{
unsigned int i;
int ret;
void *ptr;
ret = GNUNET_YES;
for (i=0; NULL != spec[i].field_name; i++)
{
if (0 == spec[i].destination_size_in)
{
ptr = NULL;
parse_variable_json_data (connection, root,
spec[i].field_name,
&ptr,
&spec[i].destination_size_out,
&ret);
spec[i].destination = ptr;
}
else
{
parse_fixed_json_data (connection, root,
spec[i].field_name,
spec[i].destination,
spec[i].destination_size_in,
&ret);
}
}
if (GNUNET_YES != ret)
TALER_MINT_release_parsed_data (spec);
return ret;
}
/**
* Release all memory allocated for the variable-size fields in
* the parser specification.
*
* @param spec specification to free
*/
void
TALER_MINT_release_parsed_data (struct GNUNET_MINT_ParseFieldSpec *spec)
{
unsigned int i;
for (i=0; NULL != spec[i].field_name; i++)
if ( (0 == spec[i].destination_size_in) &&
(0 != spec[i].destination_size_out) )
{
GNUNET_free (spec[i].destination);
spec[i].destination = NULL;
spec[i].destination_size_out = 0;
}
}
/**
* Extract base32crockford encoded data from request.
*
* Queues an error response to the connection if the parameter is missing or
* invalid.
*
* @param connection the MHD connection
* @param param_name the name of the parameter with the key
* @param[out] out_data pointer to store the result
* @param out_size expected size of data
* @return
* #GNUNET_YES if the the argument is present
* #GNUNET_NO if the argument is absent or malformed
* #GNUNET_SYSERR on internal error (error response could not be sent)
*/
int
TALER_MINT_mhd_request_arg_data (struct MHD_Connection *connection,
const char *param_name,
void *out_data,
size_t out_size)
{
const char *str;
str = MHD_lookup_connection_value (connection,
MHD_GET_ARGUMENT_KIND,
param_name);
if (NULL == str)
{
return (MHD_NO ==
TALER_MINT_reply_arg_missing (connection, param_name))
? GNUNET_SYSERR : GNUNET_NO;
}
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (str,
strlen (str),
out_data,
out_size))
return (MHD_NO ==
TALER_MINT_reply_arg_invalid (connection, param_name))
? GNUNET_SYSERR : GNUNET_NO;
return GNUNET_OK;
}
/**
* Extraxt variable-size base32crockford encoded data from request.
*
* Queues an error response to the connection if the parameter is missing
* or the encoding is invalid.
*
* @param connection the MHD connection
* @param param_name the name of the parameter with the key
* @param[out] out_data pointer to allocate buffer and store the result
* @param[out] out_size set to the size of the buffer allocated in @a out_data
* @return
* #GNUNET_YES if the the argument is present
* #GNUNET_NO if the argument is absent or malformed
* #GNUNET_SYSERR on internal error (error response could not be sent)
*/
int
TALER_MINT_mhd_request_var_arg_data (struct MHD_Connection *connection,
const char *param_name,
void **out_data,
size_t *out_size)
{
const char *str;
size_t slen;
size_t olen;
void *out;
str = MHD_lookup_connection_value (connection,
MHD_GET_ARGUMENT_KIND,
param_name);
if (NULL == str)
{
return (MHD_NO ==
TALER_MINT_reply_arg_missing (connection, param_name))
? GNUNET_SYSERR : GNUNET_NO;
}
slen = strlen (str);
olen = (slen * 5) / 8;
out = GNUNET_malloc (olen);
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (str,
strlen (str),
out,
olen))
{
GNUNET_free (out);
*out_size = 0;
return (MHD_NO ==
TALER_MINT_reply_arg_invalid (connection, param_name))
? GNUNET_SYSERR : GNUNET_NO;
}
*out_data = out;
*out_size = olen;
return GNUNET_OK;
}
/* end of taler-mint-httpd_parsing.c */