* Add the file imap/src/c-client/auth_bea.c, needed for the compilation

     of Alpine. Reported by Bob Bernstein.

2 files changed, 351 insertions, 1 deletions

diff --git a/.gitignore b/.gitignore
index f757616..1a3ad11 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,7 +19,6 @@ an
 alpine/alpine
 alpine/rpdump
 alpine/rpload
-c-client
 imap/OSTYPE
 imap/SPECIALS
 imap/c-client/
diff --git a/imap/src/c-client/auth_bea.c b/imap/src/c-client/auth_bea.c
new file mode 100644
index 0000000..683d769
--- /dev/null
+++ b/imap/src/c-client/auth_bea.c
@@ -0,0 +1,351 @@
+/* ========================================================================
+ * Copyright 2020 Eduardo Chappa
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 
+ * ========================================================================
+ */
+
+long auth_oauthbearer_client (authchallenge_t challenger,authrespond_t responder,
+			char *service,NETMBX *mb,void *stream, unsigned long port,
+			unsigned long *trial,char *user);
+#ifndef HTTP_OAUTH2_INCLUDED
+void mm_login_oauth2_c_client_method (NETMBX *, char *, char *, OAUTH2_S *, unsigned long, int *);
+#endif /* HTTP_OAUTH2_INCLUDED */
+
+AUTHENTICATOR auth_bea = {
+  AU_HIDE,			/* hidden */
+  BEARERNAME,			/* authenticator name */
+  NIL,				/* always valid */
+  auth_oauthbearer_client,	/* client method */
+  NIL,				/* server method */
+  NIL				/* next authenticator */
+};
+
+#define BEARER_ACCOUNT	"n,a="
+#ifndef OAUTH2_BEARER
+#define OAUTH2_BEARER	"auth=Bearer "
+#endif
+#define BEARER_HOST	"host="
+#define BEARER_PORT	"port="
+
+#ifndef OAUTH2_GENERATE_STATE
+#define OAUTH2_GENERATE_STATE
+char *oauth2_generate_state(void);
+
+/* we generate something like a guid, but not care about
+ * anything, but that it is really random.
+ */
+char *oauth2_generate_state(void)
+{
+  char rv[37];
+  int i;
+
+  rv[0] = '\0';
+  for(i = 0; i < 4; i++)
+     sprintf(rv + strlen(rv), "%x", random() % 256);
+  sprintf(rv + strlen(rv), "%c", '-');
+  for(i = 0; i < 2; i++)
+     sprintf(rv + strlen(rv), "%x", random() % 256);
+  sprintf(rv + strlen(rv), "%c", '-');
+  for(i = 0; i < 2; i++)
+     sprintf(rv + strlen(rv), "%x", random() % 256);
+  sprintf(rv + strlen(rv), "%c", '-');
+  for(i = 0; i < 2; i++)
+     sprintf(rv + strlen(rv), "%x", random() % 256);
+  sprintf(rv + strlen(rv), "%c", '-');
+  for(i = 0; i < 6; i++)
+     sprintf(rv + strlen(rv), "%x", random() % 256);
+  rv[36] = '\0';
+  return cpystr(rv);
+}
+#endif /* OAUTH2_GENERATE_STATE */
+
+/* Client authenticator
+ * Accepts: challenger function
+ *	    responder function
+ *	    SASL service name
+ *	    parsed network mailbox structure
+ *	    stream argument for functions
+ *	    pointer to current trial count
+ *	    returned user name
+ * Returns: T if success, NIL otherwise, number of trials incremented if retry
+ */
+
+long auth_oauthbearer_client (authchallenge_t challenger,authrespond_t responder,
+			char *service,NETMBX *mb,void *stream, unsigned long port,
+			unsigned long *trial,char *user)
+{
+  char *u;
+  void *challenge;
+  unsigned long clen;
+  long ret = NIL;
+  OAUTH2_S oauth2;
+  int tryanother = 0;	/* try another authentication method */
+
+  memset((void *) &oauth2, 0, sizeof(OAUTH2_S));
+				/* snarl if not SSL/TLS session */
+  if (!mb->sslflag && !mb->tlsflag)
+    mm_log ("SECURITY PROBLEM: insecure server advertised AUTH=OAUTHBEARER",WARN);
+
+				/* get initial (empty) challenge */
+  if ((challenge = (*challenger) (stream,&clen)) != NULL) {
+    fs_give ((void **) &challenge);
+    if (clen) {			/* abort if challenge non-empty */
+      mm_log ("Server bug: non-empty initial OAUTHBEARER challenge",WARN);
+      (*responder) (stream,NIL,0);
+      ret = LONGT;		/* will get a BAD response back */
+    }
+
+    mm_login_method (mb, user, (void *) &oauth2, *trial, BEARERNAME);
+
+    if(oauth2.param[OA2_State].value)
+      fs_give((void **) &oauth2.param[OA2_State].value);
+
+    oauth2.param[OA2_State].value = oauth2_generate_state();
+
+    /* 
+     * If we did not get an access token, try to get one through 
+     * our internal functions
+     */
+    if(oauth2.name && oauth2.access_token == NIL){
+       char *RefreshToken = NIL;
+
+       if(oauth2.param[OA2_RefreshToken].value)
+	 RefreshToken = cpystr(oauth2.param[OA2_RefreshToken].value);
+
+       mm_login_oauth2_c_client_method (mb, user, BEARERNAME, &oauth2, *trial, &tryanother);
+
+       /* 
+        * if we got an access token from the c_client_method call, 
+        * or somehow there was a change in the refresh token, return
+        * it to the client so that it will save it. 
+        */
+
+       if(!tryanother
+	  && (oauth2.access_token 
+	  || (!RefreshToken && oauth2.param[OA2_RefreshToken].value)
+	  || (RefreshToken && oauth2.param[OA2_RefreshToken].value
+	      && strcmp(RefreshToken, oauth2.param[OA2_RefreshToken].value))))
+         mm_login_method (mb, user, (void *) &oauth2, *trial, BEARERNAME);
+    }
+
+    /* empty challenge or user requested abort or client does not have info */
+    if(!oauth2.access_token) {
+      (*responder) (stream,NIL,0);
+      *trial = 0;		/* cancel subsequent attempts */
+      ret = LONGT;		/* will get a BAD response back */
+    }
+    else {
+      char ports[10];
+      unsigned long rlen;
+      char *t, *response;
+
+      sprintf(ports, "%lu", port);
+      rlen = strlen(BEARER_ACCOUNT) + strlen(user) + 1 + 1
+		+ strlen(BEARER_HOST) + strlen(mb->orighost) + 1
+		+ strlen(BEARER_PORT) + strlen(ports) + 1
+		+ strlen(OAUTH2_BEARER) + strlen(oauth2.access_token) + 2;
+      t = response = (char *) fs_get (rlen);
+      for (u = BEARER_ACCOUNT; *u; *t++ = *u++);
+      for (u = user; *u; *t++ = *u++);
+      *t++ = ',';
+      *t++ = '\001';		/* delimiting ^A */
+      for (u = BEARER_HOST; *u; *t++ = *u++);
+      for (u = mb->orighost; *u; *t++ = *u++);
+      *t++ = '\001';		/* delimiting ^A */
+      for (u = BEARER_PORT; *u; *t++ = *u++);
+      for (u = ports; *u; *t++ = *u++);
+      *t++ = '\001';		/* delimiting ^A */
+      for (u = OAUTH2_BEARER; *u; *t++ = *u++);
+      for (u = oauth2.access_token; *u; *t++ = *u++);
+      *t++ = '\001';		/* delimiting ^A */
+      *t++ = '\001';		/* delimiting ^A */
+      if ((*responder) (stream,response,rlen)) {
+	if ((challenge = (*challenger) (stream,&clen)) != NULL)
+	  fs_give ((void **) &challenge);
+	else {
+	  ++*trial;				/* can try again if necessary */
+	  ret = *trial < 3 ? LONGT : NIL;	/* check the authentication */
+	  /* When the Access Token expires we fail once, but after we get
+	   * a new one, we should succeed at the second attempt. If the
+	   * Refresh Token has expired somehow, we invalidate it if we
+	   * reach *trial to 3. This forces the process to restart later on.
+	   */
+	  if(*trial == 3){
+	     if(oauth2.param[OA2_State].value)
+		fs_give((void **) &oauth2.param[OA2_State].value);
+	     fs_give((void **) &oauth2.param[OA2_RefreshToken].value);
+	     fs_give((void **) &oauth2.access_token);
+	     oauth2.expiration = 0L;
+	  }
+	}
+      }
+      fs_give ((void **) &response);
+    }
+  }
+  if (!ret || !oauth2.name || tryanother) 
+      *trial = 65535; 			/* don't retry if bad protocol */
+  return ret;
+}
+
+#ifndef HTTP_OAUTH2_INCLUDED
+#define HTTP_OAUTH2_INCLUDED
+/* 
+ * The code above is enough to implement OAUTHBEARER, all one needs is the username
+ * and access token and give it to the function above. However, normal users cannot
+ * be expected to get the access token, so we ask the client to help with getting 
+ * the access token, refresh token and expire values, so the code below is written
+ * to help with that.
+ */
+
+#include "http.h"
+#include "json.h"
+
+void 
+mm_login_oauth2_c_client_method (NETMBX *mb, char *user, char *method,
+			OAUTH2_S *oauth2, unsigned long trial, int *tryanother)
+{
+   int i;
+   HTTP_PARAM_S params[OAUTH2_PARAM_NUMBER];
+   OAUTH2_SERVER_METHOD_S RefreshMethod;
+   char *s = NULL;
+   JSON_S *json = NULL;
+
+   if(oauth2->param[OA2_Id].value == NULL || oauth2->param[OA2_Secret].value == NULL){
+     oauth2clientinfo_t ogci =
+		(oauth2clientinfo_t) mail_parameters (NIL, GET_OA2CLIENTINFO, NIL);
+
+     if(ogci) (*ogci)(oauth2->name, &oauth2->param[OA2_Id].value,
+				&oauth2->param[OA2_Secret].value);
+   }
+
+   if(oauth2->param[OA2_Id].value == NULL || oauth2->param[OA2_Secret].value == NULL)
+      return;
+
+   /* first check if we have a refresh token, and in that case use it */
+   if(oauth2->param[OA2_RefreshToken].value){
+
+     RefreshMethod = oauth2->server_mthd[OA2_GetAccessTokenFromRefreshToken];
+     for(i = 0; RefreshMethod.params[i] != OA2_End; i++){
+	OA2_type j = RefreshMethod.params[i];
+	params[i].name  = oauth2->param[j].name;
+	params[i].value = oauth2->param[j].value;
+     }
+     params[i].name = params[i].value = NULL;
+
+     if(strcmp(RefreshMethod.name, "POST") == 0)
+	s = http_post_param(RefreshMethod.urlserver, params);
+     else if(strcmp(RefreshMethod.name, "POST2") == 0)
+	s = http_post_param2(RefreshMethod.urlserver, params);
+
+     if(s){
+	unsigned char *t, *u;
+	if((t = strstr(s, "\r\n\r\n")) && (u = strchr(t, '{')))
+	   json = json_parse(&u);
+	fs_give((void **) &s);
+     }
+
+     if(json != NULL){
+	JSON_X *jx;
+
+	jx = json_body_value(json, "access_token");
+	if(jx && jx->jtype == JString)
+	   oauth2->access_token = cpystr((char *) jx->value);
+
+	jx = json_body_value(json, "expires_in");
+	if(jx){
+	   if(jx->jtype == JString){
+	      unsigned long *l = fs_get(sizeof(unsigned long));
+	      *l = atol((char *) jx->value);
+	      fs_give(&jx->value);
+	      jx->value = (void *) l;
+	      jx->jtype = JLong;
+	   }
+	   if(jx->jtype == JLong)
+	      oauth2->expiration   = time(0) + *(unsigned long *) jx->value;
+	}
+
+	json_free(&json);
+     }
+     return;
+   }
+   /* 
+    * else, we do not have a refresh token, nor an access token.
+    * We need to start the process to get an access code. We use this
+    * to get an access token and refresh token.
+    */
+   { 
+     RefreshMethod = oauth2->server_mthd[OA2_GetAccessCode];
+     for(i = 0; RefreshMethod.params[i] != OA2_End; i++){
+	OA2_type j = RefreshMethod.params[i];
+	params[i].name  = oauth2->param[j].name;
+	params[i].value = oauth2->param[j].value;
+     }
+     params[i].name = params[i].value = NULL;
+
+     if(strcmp(RefreshMethod.name, "GET") == 0){
+	char *url = http_get_param_url(RefreshMethod.urlserver, params);
+	oauth2getaccesscode_t ogac = 
+	(oauth2getaccesscode_t) mail_parameters (NIL, GET_OA2CLIENTGETACCESSCODE, NIL);
+
+	if(ogac)
+	  oauth2->param[OA2_Code].value = (*ogac)(url, BEARERNAME, oauth2, tryanother);
+     }
+
+     if(oauth2->param[OA2_Code].value){
+        RefreshMethod = oauth2->server_mthd[OA2_GetAccessTokenFromAccessCode];
+        for(i = 0; RefreshMethod.params[i] != OA2_End; i++){
+	   OA2_type j = RefreshMethod.params[i];
+	   params[i].name  = oauth2->param[j].name;
+	   params[i].value = oauth2->param[j].value;
+        }
+        params[i].name = params[i].value = NULL;
+
+        if(strcmp(RefreshMethod.name, "POST") == 0)
+	   s = http_post_param(RefreshMethod.urlserver, params);
+	else if(strcmp(RefreshMethod.name, "POST2") == 0)
+	   s = http_post_param2(RefreshMethod.urlserver, params);
+
+        if(s){
+	   unsigned char *t, *u;
+	   if((t = strstr(s, "\r\n\r\n")) && (u = strchr(t, '{')))
+		json = json_parse(&u);
+	   fs_give((void **) &s);
+        }
+
+	if(json != NULL){
+	   JSON_X *jx;
+
+	   jx = json_body_value(json, "refresh_token");
+	   if(jx && jx->jtype == JString)
+	      oauth2->param[OA2_RefreshToken].value = cpystr((char *) jx->value);
+
+	   jx = json_body_value(json, "access_token");
+	   if(jx && jx->jtype == JString)
+	      oauth2->access_token = cpystr((char *) jx->value);
+
+	   jx = json_body_value(json, "expires_in");
+	   if(jx){
+	      if(jx->jtype == JString){
+		unsigned long *l = fs_get(sizeof(unsigned long));
+		*l = atol((char *) jx->value);
+		fs_give(&jx->value);
+		jx->value = (void *) l;
+		jx->jtype = JLong;
+	      }
+	      if(jx->jtype == JLong)
+	         oauth2->expiration = time(0) + *(unsigned long *) jx->value;
+	   }
+	   json_free(&json);
+	}
+     }
+     return;
+   }
+}
+#endif /* HTTP_OAUTH2_INCLUDED */