1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/* ========================================================================
* Copyright 2018 - 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_oauth2_client (authchallenge_t challenger,authrespond_t responder, char *base,
char *service,NETMBX *mb,void *stream, unsigned long port,
unsigned long *trial,char *user);
AUTHENTICATOR auth_oa2 = {
AU_HIDE | AU_SINGLE, /* hidden */
OA2NAME, /* authenticator name */
NIL, /* always valid */
auth_oauth2_client, /* client method */
NIL, /* server method */
NIL /* next authenticator */
};
#define OAUTH2_USER "user="
#define OAUTH2_BEARER "auth=Bearer "
/* 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_oauth2_client (authchallenge_t challenger,authrespond_t responder, char *base,
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=XOAUTH2",WARN);
/* get initial (empty) challenge */
if (base || (challenge = (*challenger) (stream,&clen)) != NULL) {
if(base == NIL){
fs_give ((void **) &challenge);
if (clen) { /* abort if challenge non-empty */
mm_log ("Server bug: non-empty initial XOAUTH2 challenge",WARN);
(*responder) (stream,NIL,NIL,0);
ret = LONGT; /* will get a BAD response back */
}
}
/*
* the call to mm_login_method is supposed to return the username
* and access token. If this is not known by the application, then
* we call our internal functions to get a refresh token, access token
* and expiration time.
*
* Programmers note: We always call mm_login_method at least once.
* The first call is done with empty parameters and it indicates
* we are asking the application to load it the best it can. Then
* the application returns the loaded value. If we get it fully loaded
* we use the value, but if we don't get it fully loaded, we call
* our internal functions to try to fully load it.
*
* If in the internal call we get it loaded, then we use these values
* to log in. At this time we call the app to send back the loaded values
* so it can save them for the next time we call. This is done in a
* second call to mm_login_method. If we do not get oauth2 back with
* fully loaded values we cancel authentication completely. If the
* user cannot load this variable, then the user, through the client,
* should disable XOAUTH2 as an authentication method and try a new one.
*
* If we make our internal mm_login_oauth2_c_client_method call,
* we might still need to call the client to get the access token,
* this is done through a callback declared by the client. If we need
* that information, but the callback is not declared, this process
* will fail, so we will check if that call is declared as soon as we
* know we should start it, and we will only start it if this callback
* is declared.
*
* We start this process by calling the client and loading oauth2
* with the required information as best as we can.
*/
mm_login_method (mb, user, (void *) &oauth2, *trial, OA2NAME);
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, OA2NAME, &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)
|| oauth2.cancel_refresh_token)))
mm_login_method (mb, user, (void *) &oauth2, *trial, OA2NAME);
}
/* empty challenge or user requested abort or client does not have info */
if(tryanother || !oauth2.access_token) {
if (!base) (*responder) (stream,base,NIL,0);
*trial = 0; /* cancel subsequent attempts */
ret = base ? NIL : LONGT; /* will get a BAD response back */
}
else {
unsigned long rlen = strlen(OAUTH2_USER) + strlen(user)
+ strlen(OAUTH2_BEARER) + strlen(oauth2.access_token) + 1 + 2;
char *response = (char *) fs_get (rlen + 1);
sprintf(response, "%s%s\001%s%s\001\001", OAUTH2_USER, user, OAUTH2_BEARER, oauth2.access_token);
if ((*responder) (stream,base,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)
*trial = 65535; /* don't retry if bad protocol */
}
}
if(oauth2.param[OA2_Id].value) fs_give((void **) &oauth2.param[OA2_Id].value);
if(oauth2.param[OA2_Secret].value) fs_give((void **) &oauth2.param[OA2_Secret].value);
if(oauth2.param[OA2_Tenant].value) fs_give((void **) &oauth2.param[OA2_Tenant].value);
return ret;
}
|
