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json: Add command "getmore" to gpgme-json.

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* src/gpgme-json.c (MIN_REPLY_CHUNK_SIZE): New const.
(DEF_REPLY_CHUNK_SIZE): New const.
(MAX_REPLY_CHUNK_SIZE): New const.
(pending_data): New var.
(add_base64_to_object): Chnage to take a plain data pointer.
(get_chunksize): New.
(make_data_object): New.
(op_encrypt): Get chunksize and use make_data_object.
(op_getmore): New.
(process_request): Release pending data for all commands but "getmore"
and "help".
--

Native messaging has a limit on the data it may receive in one
request.  Thus the caller needs to watch for the "more" flag and
request the remaining data using "getmore" in a loop.

Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2018-04-18 11:12:46 +02:00
parent e69b175e8e
commit ed1052842d
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
1 changed files with 230 additions and 48 deletions
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276
src/gpgme-json.c
View File

@ -49,6 +49,16 @@ int main (void){fputs ("Build with Libgpg-error >= 1.28!\n", stderr);return 1;}
/* We don't allow a request with more than 64 MiB. */
#define MAX_REQUEST_SIZE (64 * 1024 * 1024)
/* Minimal, default and maximum chunk size for returned data. The
* first chunk is returned directly. If the "more" flag is also
* returned, a "getmore" command needs to be used to get the next
* chunk. Right now this value covers just the value of the "data"
* element; so to cover for the other returned objects this values
* needs to be lower than the maximum allowed size of the browser. */
#define MIN_REPLY_CHUNK_SIZE 512
#define DEF_REPLY_CHUNK_SIZE (512 * 1024)
#define MAX_REPLY_CHUNK_SIZE (10 * 1024 * 1024)
static void xoutofcore (const char *type) GPGRT_ATTR_NORETURN;
static cjson_t error_object_v (cjson_t json, const char *message,
@ -64,6 +74,16 @@ static int opt_interactive;
/* True is debug mode is active. */
static int opt_debug;
/* Pending data to be returned by a getmore command. */
static struct
{
char *buffer; /* Malloced data or NULL if not used. */
size_t length; /* Length of that data. */
size_t written; /* # of already written bytes from BUFFER. */
const char *type;/* The "type" of the data. */
int base64; /* The "base64" flag of the data. */
} pending_data;
/*
* Helper functions and macros
@ -147,11 +167,12 @@ xjson_AddBoolToObject (cjson_t object, const char *name, int abool)
return ;
}
/* This is similar to cJSON_AddStringToObject but takes a gpgme DATA
* object and adds it under NAME as a base 64 encoded string to
* OBJECT. Ownership of DATA is transferred to this function. */
/* This is similar to cJSON_AddStringToObject but takes (DATA,
* DATALEN) and adds it under NAME as a base 64 encoded string to
* OBJECT. */
static gpg_error_t
add_base64_to_object (cjson_t object, const char *name, gpgme_data_t data)
add_base64_to_object (cjson_t object, const char *name,
const void *data, size_t datalen)
{
#if GPGRT_VERSION_NUMBER < 0x011d00 /* 1.29 */
return gpg_error (GPG_ERR_NOT_SUPPORTED);
@ -161,7 +182,6 @@ add_base64_to_object (cjson_t object, const char *name, gpgme_data_t data)
gpgrt_b64state_t state = NULL;
cjson_t j_str = NULL;
void *buffer = NULL;
size_t buflen;
fp = es_fopenmem (0, "rwb");
if (!fp)
@ -176,20 +196,9 @@ add_base64_to_object (cjson_t object, const char *name, gpgme_data_t data)
goto leave;
}
gpgme_data_write (data, "", 1); /* Make sure we have a string. */
buffer = gpgme_data_release_and_get_mem (data, &buflen);
data = NULL;
if (!buffer)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = gpgrt_b64enc_write (state, buffer, buflen);
err = gpgrt_b64enc_write (state, data, datalen);
if (err)
goto leave;
xfree (buffer);
buffer = NULL;
err = gpgrt_b64enc_finish (state);
state = NULL;
@ -227,7 +236,6 @@ add_base64_to_object (cjson_t object, const char *name, gpgme_data_t data)
cJSON_Delete (j_str);
gpgrt_b64enc_finish (state);
es_fclose (fp);
gpgme_data_release (data);
return err;
#endif
}
@ -355,6 +363,29 @@ get_protocol (cjson_t json, gpgme_protocol_t *r_protocol)
}
/* Get the chunksize from JSON and store it at R_CHUNKSIZE. */
static gpg_error_t
get_chunksize (cjson_t json, size_t *r_chunksize)
{
cjson_t j_item;
*r_chunksize = DEF_REPLY_CHUNK_SIZE;
j_item = cJSON_GetObjectItem (json, "chunksize");
if (!j_item)
;
else if (!cjson_is_number (j_item))
return gpg_error (GPG_ERR_INV_VALUE);
else if ((size_t)j_item->valueint < MIN_REPLY_CHUNK_SIZE)
*r_chunksize = MIN_REPLY_CHUNK_SIZE;
else if ((size_t)j_item->valueint > MAX_REPLY_CHUNK_SIZE)
*r_chunksize = MAX_REPLY_CHUNK_SIZE;
else
*r_chunksize = (size_t)j_item->valueint;
return 0;
}
/* Extract the keys from the "keys" array in the JSON object. On
* success a string with the keys identifiers is stored at R_KEYS.
* The keys in that string are LF delimited. On failure an error code
@ -549,10 +580,80 @@ data_from_base64_string (gpgme_data_t *r_data, cjson_t json)
/*
* Implementaion of the commands.
* Implementation of the commands.
*/
/* Create a "data" object and the "type", "base64" and "more" flags
* from DATA and append them to RESULT. Ownership if DATA is
* transferred to this function. TYPE must be a fixed string.
* CHUNKSIZE is the chunksize requested from the caller. Note that
* op_getmore has similar code but works on PENDING_DATA which is set
* here. */
static gpg_error_t
make_data_object (cjson_t result, gpgme_data_t data, size_t chunksize,
const char *type, int base64)
{
gpg_error_t err;
char *buffer;
size_t buflen;
int c;
/* Adjust the chunksize if we need to do base64 conversion. */
if (base64)
chunksize = (chunksize / 4) * 3;
if (!base64) /* Make sure that we really have a string. */
gpgme_data_write (data, "", 1);
buffer = gpgme_data_release_and_get_mem (data, &buflen);
data = NULL;
if (!buffer)
{
err = gpg_error_from_syserror ();
goto leave;
}
xjson_AddStringToObject (result, "type", type);
xjson_AddBoolToObject (result, "base64", base64);
if (buflen > chunksize)
{
xjson_AddBoolToObject (result, "more", 1);
c = buffer[chunksize];
buffer[chunksize] = 0;
if (base64)
err = add_base64_to_object (result, "data", buffer, chunksize);
else
err = cjson_AddStringToObject (result, "data", buffer);
buffer[chunksize] = c;
if (err)
goto leave;
pending_data.buffer = buffer;
buffer = NULL;
pending_data.length = buflen;
pending_data.written = chunksize;
pending_data.type = type;
pending_data.base64 = base64;
}
else
{
if (base64)
err = add_base64_to_object (result, "data", buffer, buflen);
else
err = cjson_AddStringToObject (result, "data", buffer);
}
leave:
gpgme_free (buffer);
return err;
}
static const char hlp_encrypt[] =
"op: \"encrypt\"\n"
"keys: Array of strings with the fingerprints or user-ids\n"
@ -562,6 +663,7 @@ static const char hlp_encrypt[] =
"\n"
"Optional parameters:\n"
"protocol: Either \"openpgp\" (default) or \"cms\".\n"
"chunksize: Max number of bytes in the resulting \"data\".\n"
"\n"
"Optional boolean flags (default is false):\n"
"base64: Input data is base64 encoded.\n"
@ -578,13 +680,15 @@ static const char hlp_encrypt[] =
"data: Unless armor mode is used a Base64 encoded binary\n"
" ciphertext. In armor mode a string with an armored\n"
" OpenPGP or a PEM message.\n"
"base64: Boolean indicating whether data is base64 encoded.";
"base64: Boolean indicating whether data is base64 encoded.\n"
"more: Optional boolean indicating that \"getmore\" is required.";
static gpg_error_t
op_encrypt (cjson_t request, cjson_t result)
{
gpg_error_t err;
gpgme_ctx_t ctx = NULL;
gpgme_protocol_t protocol;
size_t chunksize;
int opt_base64;
char *keystring = NULL;
cjson_t j_input;
@ -596,6 +700,8 @@ op_encrypt (cjson_t request, cjson_t result)
if ((err = get_protocol (request, &protocol)))
goto leave;
ctx = get_context (protocol);
if ((err = get_chunksize (request, &chunksize)))
goto leave;
if ((err = get_boolean_flag (request, "base64", 0, &opt_base64)))
goto leave;
@ -693,43 +799,106 @@ op_encrypt (cjson_t request, cjson_t result)
gpgme_data_release (input);
input = NULL;
xjson_AddStringToObject (result, "type", "ciphertext");
/* If armoring is used we do not need to base64 the output. */
xjson_AddBoolToObject (result, "base64", !gpgme_get_armor (ctx));
if (gpgme_get_armor (ctx))
{
char *buffer;
/* Make sure that we really have a string. */
gpgme_data_write (output, "", 1);
buffer = gpgme_data_release_and_get_mem (output, NULL);
if (!buffer)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = cjson_AddStringToObject (result, "data", buffer);
gpgme_free (buffer);
if (err)
goto leave;
}
else
{
err = add_base64_to_object (result, "data", output);
/* We need to base64 if armoring has not been requested. */
err = make_data_object (result, output, chunksize,
"ciphertext", !gpgme_get_armor (ctx));
output = NULL;
if (err)
goto leave;
}
leave:
xfree (keystring);
release_context (ctx);
gpgme_data_release (input);
gpgme_data_release (output);
return err;
}
static const char hlp_getmore[] =
"op: \"getmore\"\n"
"\n"
"Optional parameters:\n"
"chunksize: Max number of bytes in the \"data\" object.\n"
"\n"
"Response on success:\n"
"type: Type of the pending data\n"
"data: The next chunk of data\n"
"base64: Boolean indicating whether data is base64 encoded\n"
"more: Optional boolean requesting another \"getmore\".";
static gpg_error_t
op_getmore (cjson_t request, cjson_t result)
{
gpg_error_t err;
int c;
size_t n;
size_t chunksize;
if ((err = get_chunksize (request, &chunksize)))
goto leave;
/* Adjust the chunksize if we need to do base64 conversion. */
if (pending_data.base64)
chunksize = (chunksize / 4) * 3;
/* Do we have anything pending? */
if (!pending_data.buffer)
{
err = gpg_error (GPG_ERR_NO_DATA);
error_object (result, "Operation not possible: %s", gpg_strerror (err));
goto leave;
}
xjson_AddStringToObject (result, "type", pending_data.type);
xjson_AddBoolToObject (result, "base64", pending_data.base64);
if (pending_data.written >= pending_data.length)
{
/* EOF reached. This should not happen but we return an empty
* string once in case of client errors. */
gpgme_free (pending_data.buffer);
pending_data.buffer = NULL;
xjson_AddBoolToObject (result, "more", 0);
err = cjson_AddStringToObject (result, "data", "");
}
else
{
n = pending_data.length - pending_data.written;
if (n > chunksize)
{
n = chunksize;
xjson_AddBoolToObject (result, "more", 1);
}
else
xjson_AddBoolToObject (result, "more", 0);
c = pending_data.buffer[pending_data.written + n];
pending_data.buffer[pending_data.written + n] = 0;
if (pending_data.base64)
err = add_base64_to_object (result, "data",
(pending_data.buffer
+ pending_data.written), n);
else
err = cjson_AddStringToObject (result, "data",
(pending_data.buffer
+ pending_data.written));
pending_data.buffer[pending_data.written + n] = c;
if (!err)
{
pending_data.written += n;
if (pending_data.written >= pending_data.length)
{
gpgme_free (pending_data.buffer);
pending_data.buffer = NULL;
}
}
}
leave:
return err;
}
static const char hlp_help[] =
"The tool expects a JSON object with the request and responds with\n"
"another JSON object. Even on error a JSON object is returned. The\n"
@ -739,6 +908,7 @@ static const char hlp_help[] =
"returned. To list all operations it is allowed to leave out \"op\" in\n"
"help mode. Supported values for \"op\" are:\n\n"
" encrypt Encrypt data.\n"
" getmore Retrieve remaining data.\n"
" help Help overview.";
static gpg_error_t
op_help (cjson_t request, cjson_t result)
@ -761,6 +931,10 @@ op_help (cjson_t request, cjson_t result)
}
/*
* Dispatcher
*/
/* Process a request and return the response. The response is a newly
* allocated string or NULL in case of an error. */
@ -774,7 +948,7 @@ process_request (const char *request)
} optbl[] = {
{ "encrypt", op_encrypt, hlp_encrypt },
{ "getmore", op_getmore, hlp_getmore },
{ "help", op_help, hlp_help },
{ NULL }
};
@ -829,6 +1003,14 @@ process_request (const char *request)
{
gpg_error_t err;
/* If this is not the "getmore" command and we have any
* pending data release that data. */
if (pending_data.buffer && optbl[idx].handler != op_getmore)
{
gpgme_free (pending_data.buffer);
pending_data.buffer = NULL;
}
err = optbl[idx].handler (json, response);
if (err)
{