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#include <fcntl.h>
#include <sys/stat.h>
#include "shopify.h"
#include "crypt.h"
#include "base64.h"
#include "regex.h"
#include "config.h"
#include "request.h"
#include "session.h"
#include "token.h"
#define AUTHORIZE_URL \
"https://%s/oauth/authorize?client_id=%s&scope=%s&redirect_uri=%s%s"\
"&state=%s"
#define AUTHORIZE_URL_LEN strlen(AUTHORIZE_URL) - strlen("%s") * 6
#define PAGE \
"<!DOCTYPE html>\n"\
"<html lang=\"en\">\n"\
"\t<head>\n"\
"\t\t<meta charset=\"utf-8\"/>\n"\
"\t</head>\n"\
"\t<body>\n"\
"\t\t<script src=\"https://unpkg.com/@shopify/app-bridge@3\"/>\n"\
"\t\t</script>\n"\
"\t\t<script>\n"\
"\t\t\tvar appBridge = window['app-bridge'];\n"\
"\t\t\tvar redirect = appBridge.actions.Redirect;\n"\
"\t\t\tredirect.create(appBridge.createApp({\n"\
"\t\t\t\tapiKey: '%s',\n"\
"\t\t\t\thost: '%s'\n"\
"\t\t\t})).dispatch(redirect.Action.REMOTE, '%s');\n"\
"\t\t</script>\n"\
"\t</body>\n"\
"</html>\n"
#define PAGE_LEN strlen(PAGE) - strlen("%s") * 3
#define FRAME "frame-ancestors https://%s https://admin.shopify.com;"
#define FRAME_LEN strlen(FRAME) - strlen("%s")
#define EMBEDDEDAPP_URL "https://%s/apps/%s/"
#define EMBEDDEDAPP_URL_LEN strlen(EMBEDDEDAPP_URL) - strlen("%s") * 2
extern inline void crypt_init();
extern inline bool crypt_maccmp(const char *, const char *, const char *);
extern inline void crypt_getnonce(char *, const size_t);
extern inline bool regex_match(const char *);
extern inline void base64_decode(unsigned char *, char **);
extern inline void config_getscopes(const char *, char **);
extern inline void request_init();
extern inline void request_token(const char *, const char *, const char *,
const char *, char **);
extern inline void request_cleanup();
extern inline void token_parse(char *, struct session *);
void shopify_init()
{
crypt_init();
request_init();
sessions = malloc(sizeof(struct session));
sessions[0].shop = NULL;
}
static enum MHD_Result getparam(void *cls, enum MHD_ValueKind kind,
const char *key, const char *val)
{
if (kind == MHD_GET_ARGUMENT_KIND) {
struct shopify_param **params = cls;
int nparams = 0;
while ((*params)[nparams].key)
nparams++;
*params = realloc(*params, sizeof(struct shopify_param)
* (nparams + 2));
(*params)[nparams].key = malloc(strlen(key) + 1);
strcpy((*params)[nparams].key, key);
(*params)[nparams].val = malloc(strlen(val) + 1);
strcpy((*params)[nparams].val, val);
(*params)[nparams + 1].key = NULL;
}
return MHD_YES;
}
static inline void clear(struct shopify_param params[])
{
int i = 0;
while (params[i].key) {
free(params[i].val);
free(params[i++].key);
}
}
static int paramcmp(const void *param1, const void *param2)
{
return strcmp(((struct shopify_param *)param1)->key,
((struct shopify_param *)param2)->key);
}
static int sessioncmp(const void *session1, const void *session2)
{
return strcmp(((struct session *)session1)->shop,
((struct session *)session2)->shop);
}
bool shopify_valid(struct MHD_Connection *conn, const char *url,
const char *redir_url, const char *secret_key,
struct shopify_param *params[])
{
(*params)[0].key = NULL;
MHD_get_connection_values(conn, MHD_GET_ARGUMENT_KIND, getparam,
params);
int nparams = 0;
while ((*params)[nparams].key)
nparams++;
if (!nparams)
return false;
qsort(*params, nparams, sizeof(struct shopify_param), paramcmp);
char *shop = NULL;
struct shopify_param *param = bsearch(&(struct shopify_param)
{ "shop" }, *params, nparams,
sizeof(struct shopify_param), paramcmp);
if (param)
shop = param->val;
if (!shop || !regex_match(shop)) {
clear(*params);
return false;
}
param = NULL;
char *query = NULL;
for (int i = 0; i < nparams; i++) {
const char *key = (*params)[i].key;
const char *val = (*params)[i].val;
if (strcmp(key, "hmac")) {
size_t query_len = query ? strlen(query) : 0;
bool last = i == nparams - 1;
query = realloc(query, query_len + strlen(key)
+ strlen(val) + !last + 2);
query[query_len] = '\0';
sprintf(query, "%s%s=%s%s", query, key, val,
last ? "" : "&");
}
}
char *hmac = NULL;
param = bsearch(&(struct shopify_param){ "hmac" }, *params, nparams,
sizeof(struct shopify_param), paramcmp);
if (param)
hmac = param->val;
if (!hmac || !crypt_maccmp(secret_key, query, hmac)) {
clear(*params);
free(query);
return false;
}
free(query);
if (strcmp(url, redir_url))
return true;
char *state = ((struct shopify_param *)bsearch(&(struct shopify_param)
{ "state" }, *params, nparams,
sizeof(struct shopify_param), paramcmp))->val;
int nsessions = 0;
while (sessions[nsessions].shop)
nsessions++;
qsort(sessions, nsessions, sizeof(struct session), sessioncmp);
struct session *session = bsearch(&(struct session){ shop }, sessions,
nsessions, sizeof(struct session), sessioncmp);
if (strcmp(state, session->nonce)) {
clear(*params);
return false;
}
return true;
}
static inline int redirect(const char *host, const char *id,
struct MHD_Response **resp, struct MHD_Connection *conn)
{
char url[EMBEDDEDAPP_URL_LEN + strlen(host) + strlen(id) + 1];
sprintf(url, EMBEDDEDAPP_URL, host, id);
*resp = MHD_create_response_from_buffer(0, "", MHD_RESPMEM_PERSISTENT);
MHD_add_response_header(*resp, "Location", url);
return MHD_queue_response(conn, MHD_HTTP_PERMANENT_REDIRECT, *resp);
}
enum MHD_Result shopify_respond(struct shopify_param params[], const char *url,
const char *redir_url, const char *app_url, const char *app_id,
const char *key, const char *secret_key, const char *toml_path,
const char *html_path, struct MHD_Connection *conn,
struct MHD_Response **resp)
{
int nparams = 0;
while (params[nparams].key)
nparams++;
char *shop = ((struct shopify_param *)bsearch(&(struct shopify_param)
{ "shop" }, params, nparams,
sizeof(struct shopify_param), paramcmp))->val;
const size_t shop_len = strlen(shop);
char *host = ((struct shopify_param *)bsearch(&(struct shopify_param)
{ "host" }, params, nparams,
sizeof(struct shopify_param), paramcmp))->val;
struct shopify_param *param = bsearch(&(struct shopify_param)
{ "embedded" }, params, nparams,
sizeof(struct shopify_param), paramcmp);
bool embedded = param && !strcmp(param->val, "1");
char *decoded_host;
base64_decode((unsigned char *)host, &decoded_host);
int nsessions = 0;
while (sessions[nsessions].shop)
nsessions++;
qsort(sessions, nsessions, sizeof(struct session), sessioncmp);
struct session *session = bsearch(&(struct session){ shop }, sessions,
nsessions, sizeof(struct session), sessioncmp);
const size_t key_len = strlen(key);
char frame[FRAME_LEN + shop_len + 1];
sprintf(frame, FRAME, shop);
enum MHD_Result ret;
if (!strcmp(url, redir_url)) {
const char *code = ((struct shopify_param *)bsearch(
&(struct shopify_param){ "code" },
params, nparams,
sizeof(struct shopify_param),
paramcmp))->val;
char *token = NULL;
request_token(decoded_host, key, secret_key, code, &token);
token_parse(token, session);
free(token);
ret = redirect(decoded_host, app_id, resp, conn);
} else if (session && session->token) {
if (embedded) {
int fd = open(toml_path, O_RDONLY);
struct stat sb;
fstat(fd, &sb);
char index[sb.st_size + 1];
read(fd, index, sb.st_size);
close(fd);
*resp = MHD_create_response_from_buffer(sb.st_size,
index, MHD_RESPMEM_MUST_COPY);
MHD_add_response_header(*resp,
"Content-Security-Policy", frame);
ret = MHD_queue_response(conn, MHD_HTTP_OK, *resp);
} else
ret = redirect(decoded_host, app_id, resp, conn);
} else {
const size_t decoded_host_len = strlen(decoded_host);
char *scopes = NULL;
config_getscopes(html_path, &scopes);
const size_t scopes_len = strlen(scopes);
static const size_t nonce_len = 64;
char nonce[nonce_len + 1];
crypt_getnonce(nonce, nonce_len);
const size_t authorize_url_len = AUTHORIZE_URL_LEN
+ decoded_host_len + key_len + scopes_len
+ strlen(app_url) + strlen(redir_url) + nonce_len;
char authorize_url[authorize_url_len + 1];
sprintf(authorize_url, AUTHORIZE_URL, decoded_host, key, scopes,
app_url, redir_url, nonce);
free(scopes);
sessions = realloc(sessions, sizeof(struct session)
* (nsessions + 2));
sessions[nsessions].shop = malloc(shop_len + 1);
strcpy(sessions[nsessions].shop, shop);
sessions[nsessions].nonce = malloc(nonce_len + 1);
strcpy(sessions[nsessions].nonce, nonce);
sessions[nsessions + 1].shop = NULL;
if (embedded) {
const size_t page_len = PAGE_LEN + key_len
+ strlen(host) + authorize_url_len;
char page[page_len + 1];
sprintf(page, PAGE, key, host, authorize_url);
*resp = MHD_create_response_from_buffer(page_len,
page, MHD_RESPMEM_MUST_COPY);
MHD_add_response_header(*resp,
"Content-Security-Policy", frame);
ret = MHD_queue_response(conn, MHD_HTTP_OK, *resp);
} else {
*resp = MHD_create_response_from_buffer(0, "",
MHD_RESPMEM_PERSISTENT);
MHD_add_response_header(*resp, "Location",
authorize_url);
ret = MHD_queue_response(conn,
MHD_HTTP_TEMPORARY_REDIRECT, *resp);
}
}
free(decoded_host);
clear(params);
return ret;
}
void shopify_cleanup()
{
request_cleanup();
int i = 0;
while (sessions[i].shop) {
if (sessions[i].scope)
free(sessions[i].scope);
if (sessions[i].token)
free(sessions[i].token);
free(sessions[i].nonce);
free(sessions[i++].shop);
}
free(sessions);
}
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