summaryrefslogtreecommitdiffstats
path: root/src/sessions.c
blob: e3a87854a2fda157a697b75adaec1cff1b040feb (plain)
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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
/* Copyright (C) 2014 mod_auth_gssapi authors - See COPYING for (C) terms */

#include "mod_auth_gssapi.h"

APLOG_USE_MODULE(auth_gssapi);

static APR_OPTIONAL_FN_TYPE(ap_session_load) *mag_sess_load_fn = NULL;
static APR_OPTIONAL_FN_TYPE(ap_session_get) *mag_sess_get_fn = NULL;
static APR_OPTIONAL_FN_TYPE(ap_session_set) *mag_sess_set_fn = NULL;

void mag_post_config_session(void)
{
    mag_sess_load_fn = APR_RETRIEVE_OPTIONAL_FN(ap_session_load);
    mag_sess_get_fn = APR_RETRIEVE_OPTIONAL_FN(ap_session_get);
    mag_sess_set_fn = APR_RETRIEVE_OPTIONAL_FN(ap_session_set);
}

static apr_status_t mag_session_load(request_rec *req, session_rec **sess)
{
    if (mag_sess_load_fn) {
        return mag_sess_load_fn(req, sess);
    }
    return DECLINED;
}

static apr_status_t mag_session_get(request_rec *req, session_rec *sess,
                                    const char *key, const char **value)
{
    if (mag_sess_get_fn) {
        return mag_sess_get_fn(req, sess, key, value);
    }
    return DECLINED;
}

static apr_status_t mag_session_set(request_rec *req, session_rec *sess,
                                    const char *key, const char *value)
{
    if (mag_sess_set_fn) {
        return mag_sess_set_fn(req, sess, key, value);
    }
    return DECLINED;
}

#define MAG_BEARER_KEY "MagBearerToken"

void mag_check_session(request_rec *req,
                       struct mag_config *cfg, struct mag_conn **conn)
{
    struct mag_conn *mc;
    apr_status_t rc;
    session_rec *sess = NULL;
    const char *sessval = NULL;
    int declen;
    struct databuf ctxbuf = { 0 };
    struct databuf cipherbuf = { 0 };
    char *next, *last;
    time_t expiration;

    rc = mag_session_load(req, &sess);
    if (rc != OK || sess == NULL) {
        ap_log_rerror(APLOG_MARK, APLOG_INFO|APLOG_NOERRNO, 0, req,
                      "Sessions not available, no cookies!");
        return;
    }

    mc = *conn;
    if (!mc) {
        mc = apr_pcalloc(req->pool, sizeof(struct mag_conn));
        if (!mc) return;

        mc->parent = req->pool;
        *conn = mc;
    }

    rc = mag_session_get(req, sess, MAG_BEARER_KEY, &sessval);
    if (rc != OK) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
                      "Failed to get session data!");
        return;
    }
    if (!sessval) {
        /* no session established, just return */
        return;
    }

    if (!cfg->mag_skey) {
        ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
                      "Session key not available, no cookies!");
        /* we do not have a key, just return */
        return;
    }

    /* decode it */
    declen = apr_base64_decode_len(sessval);
    cipherbuf.value = apr_palloc(req->pool, declen);
    if (!cipherbuf.value) return;
    cipherbuf.length = (int)apr_base64_decode((char *)cipherbuf.value, sessval);

    rc = UNSEAL_BUFFER(req->pool, cfg->mag_skey, &cipherbuf, &ctxbuf);
    if (rc != OK) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
                      "Failed to unseal session data!");
        return;
    }

    /* get time */
    next = apr_strtok((char *)ctxbuf.value, ":", &last);
    expiration = (time_t)apr_atoi64(next);
    if (expiration < time(NULL)) {
        /* credentials fully expired, return nothing */
        return;
    }

    /* user name is next */
    next = apr_strtok(NULL, ":", &last);
    mc->user_name = apr_pstrdup(mc->parent, next);
    if (!mc->user_name) return;

    /* gssapi name (often a principal) is last.
     * (because it may contain the separator as a valid char we
     * just read last as is, without further tokenizing */
    mc->gss_name = apr_pstrdup(mc->parent, last);
    if (!mc->gss_name) return;

    /* OK we have a valid token */
    mc->established = true;
}

void mag_attempt_session(request_rec *req,
                         struct mag_config *cfg, struct mag_conn *mc)
{
    session_rec *sess = NULL;
    char *sessval = NULL;
    struct databuf plainbuf = { 0 };
    struct databuf cipherbuf = { 0 };
    struct databuf ctxbuf = { 0 };
    apr_status_t rc;

    /* we save the session only if the authentication is established */

    if (!mc->established) return;
    rc = mag_session_load(req, &sess);
    if (rc != OK || sess == NULL) {
        ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
                      "Sessions not available, can't send cookies!");
        return;
    }

    if (!cfg->mag_skey) {
        ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
                      "Session key not available, generating new one.");
        rc = SEAL_KEY_CREATE(cfg->pool, &cfg->mag_skey, NULL);
        if (rc != OK) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
                          "Failed to create sealing key!");
            return;
        }
    }

    sessval = apr_psprintf(req->pool, "%ld:%s:%s",
                           (long)mc->expiration, mc->user_name, mc->gss_name);
    if (!sessval) return;

    plainbuf.length = strlen(sessval) + 1;
    plainbuf.value = (unsigned char *)sessval;

    rc = SEAL_BUFFER(req->pool, cfg->mag_skey, &plainbuf, &cipherbuf);
    if (rc != OK) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
                      "Failed to seal session data!");
        return;
    }

    ctxbuf.length = apr_base64_encode_len(cipherbuf.length);
    ctxbuf.value = apr_pcalloc(req->pool, ctxbuf.length);
    if (!ctxbuf.value) return;

    ctxbuf.length = apr_base64_encode((char *)ctxbuf.value,
                                      (char *)cipherbuf.value,
                                      cipherbuf.length);

    rc = mag_session_set(req, sess, MAG_BEARER_KEY, (char *)ctxbuf.value);
    if (rc != OK) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
                      "Failed to set session data!");
        return;
    }
}