1/*
2 * HTTP authentication
3 * Copyright (c) 2010 Martin Storsjo
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "httpauth.h"
23#include "libavutil/base64.h"
24#include "libavutil/avstring.h"
25#include "internal.h"
26#include "libavutil/random_seed.h"
27#include "libavutil/md5.h"
28#include "urldecode.h"
29#include "avformat.h"
30
31static void handle_basic_params(HTTPAuthState *state, const char *key,
32                                int key_len, char **dest, int *dest_len)
33{
34    if (!strncmp(key, "realm=", key_len)) {
35        *dest     =        state->realm;
36        *dest_len = sizeof(state->realm);
37    }
38}
39
40static void handle_digest_params(HTTPAuthState *state, const char *key,
41                                 int key_len, char **dest, int *dest_len)
42{
43    DigestParams *digest = &state->digest_params;
44
45    if (!strncmp(key, "realm=", key_len)) {
46        *dest     =        state->realm;
47        *dest_len = sizeof(state->realm);
48    } else if (!strncmp(key, "nonce=", key_len)) {
49        *dest     =        digest->nonce;
50        *dest_len = sizeof(digest->nonce);
51    } else if (!strncmp(key, "opaque=", key_len)) {
52        *dest     =        digest->opaque;
53        *dest_len = sizeof(digest->opaque);
54    } else if (!strncmp(key, "algorithm=", key_len)) {
55        *dest     =        digest->algorithm;
56        *dest_len = sizeof(digest->algorithm);
57    } else if (!strncmp(key, "qop=", key_len)) {
58        *dest     =        digest->qop;
59        *dest_len = sizeof(digest->qop);
60    } else if (!strncmp(key, "stale=", key_len)) {
61        *dest     =        digest->stale;
62        *dest_len = sizeof(digest->stale);
63    }
64}
65
66static void handle_digest_update(HTTPAuthState *state, const char *key,
67                                 int key_len, char **dest, int *dest_len)
68{
69    DigestParams *digest = &state->digest_params;
70
71    if (!strncmp(key, "nextnonce=", key_len)) {
72        *dest     =        digest->nonce;
73        *dest_len = sizeof(digest->nonce);
74    }
75}
76
77static void choose_qop(char *qop, int size)
78{
79    char *ptr = strstr(qop, "auth");
80    char *end = ptr + strlen("auth");
81
82    if (ptr && (!*end || av_isspace(*end) || *end == ',') &&
83        (ptr == qop || av_isspace(ptr[-1]) || ptr[-1] == ',')) {
84        av_strlcpy(qop, "auth", size);
85    } else {
86        qop[0] = 0;
87    }
88}
89
90void ff_http_auth_handle_header(HTTPAuthState *state, const char *key,
91                                const char *value)
92{
93    if (!strcmp(key, "WWW-Authenticate") || !strcmp(key, "Proxy-Authenticate")) {
94        const char *p;
95        if (av_stristart(value, "Basic ", &p) &&
96            state->auth_type <= HTTP_AUTH_BASIC) {
97            state->auth_type = HTTP_AUTH_BASIC;
98            state->realm[0] = 0;
99            state->stale = 0;
100            ff_parse_key_value(p, (ff_parse_key_val_cb) handle_basic_params,
101                               state);
102        } else if (av_stristart(value, "Digest ", &p) &&
103                   state->auth_type <= HTTP_AUTH_DIGEST) {
104            state->auth_type = HTTP_AUTH_DIGEST;
105            memset(&state->digest_params, 0, sizeof(DigestParams));
106            state->realm[0] = 0;
107            state->stale = 0;
108            ff_parse_key_value(p, (ff_parse_key_val_cb) handle_digest_params,
109                               state);
110            choose_qop(state->digest_params.qop,
111                       sizeof(state->digest_params.qop));
112            if (!av_strcasecmp(state->digest_params.stale, "true"))
113                state->stale = 1;
114        }
115    } else if (!strcmp(key, "Authentication-Info")) {
116        ff_parse_key_value(value, (ff_parse_key_val_cb) handle_digest_update,
117                           state);
118    }
119}
120
121
122static void update_md5_strings(struct AVMD5 *md5ctx, ...)
123{
124    va_list vl;
125
126    va_start(vl, md5ctx);
127    while (1) {
128        const char* str = va_arg(vl, const char*);
129        if (!str)
130            break;
131        av_md5_update(md5ctx, str, strlen(str));
132    }
133    va_end(vl);
134}
135
136/* Generate a digest reply, according to RFC 2617. */
137static char *make_digest_auth(HTTPAuthState *state, const char *username,
138                              const char *password, const char *uri,
139                              const char *method)
140{
141    DigestParams *digest = &state->digest_params;
142    int len;
143    uint32_t cnonce_buf[2];
144    char cnonce[17];
145    char nc[9];
146    int i;
147    char A1hash[33], A2hash[33], response[33];
148    struct AVMD5 *md5ctx;
149    uint8_t hash[16];
150    char *authstr;
151
152    digest->nc++;
153    snprintf(nc, sizeof(nc), "%08x", digest->nc);
154
155    /* Generate a client nonce. */
156    for (i = 0; i < 2; i++)
157        cnonce_buf[i] = av_get_random_seed();
158    ff_data_to_hex(cnonce, (const uint8_t*) cnonce_buf, sizeof(cnonce_buf), 1);
159    cnonce[2*sizeof(cnonce_buf)] = 0;
160
161    md5ctx = av_md5_alloc();
162    if (!md5ctx)
163        return NULL;
164
165    av_md5_init(md5ctx);
166    update_md5_strings(md5ctx, username, ":", state->realm, ":", password, NULL);
167    av_md5_final(md5ctx, hash);
168    ff_data_to_hex(A1hash, hash, 16, 1);
169    A1hash[32] = 0;
170
171    if (!strcmp(digest->algorithm, "") || !strcmp(digest->algorithm, "MD5")) {
172    } else if (!strcmp(digest->algorithm, "MD5-sess")) {
173        av_md5_init(md5ctx);
174        update_md5_strings(md5ctx, A1hash, ":", digest->nonce, ":", cnonce, NULL);
175        av_md5_final(md5ctx, hash);
176        ff_data_to_hex(A1hash, hash, 16, 1);
177        A1hash[32] = 0;
178    } else {
179        /* Unsupported algorithm */
180        av_free(md5ctx);
181        return NULL;
182    }
183
184    av_md5_init(md5ctx);
185    update_md5_strings(md5ctx, method, ":", uri, NULL);
186    av_md5_final(md5ctx, hash);
187    ff_data_to_hex(A2hash, hash, 16, 1);
188    A2hash[32] = 0;
189
190    av_md5_init(md5ctx);
191    update_md5_strings(md5ctx, A1hash, ":", digest->nonce, NULL);
192    if (!strcmp(digest->qop, "auth") || !strcmp(digest->qop, "auth-int")) {
193        update_md5_strings(md5ctx, ":", nc, ":", cnonce, ":", digest->qop, NULL);
194    }
195    update_md5_strings(md5ctx, ":", A2hash, NULL);
196    av_md5_final(md5ctx, hash);
197    ff_data_to_hex(response, hash, 16, 1);
198    response[32] = 0;
199
200    av_free(md5ctx);
201
202    if (!strcmp(digest->qop, "") || !strcmp(digest->qop, "auth")) {
203    } else if (!strcmp(digest->qop, "auth-int")) {
204        /* qop=auth-int not supported */
205        return NULL;
206    } else {
207        /* Unsupported qop value. */
208        return NULL;
209    }
210
211    len = strlen(username) + strlen(state->realm) + strlen(digest->nonce) +
212              strlen(uri) + strlen(response) + strlen(digest->algorithm) +
213              strlen(digest->opaque) + strlen(digest->qop) + strlen(cnonce) +
214              strlen(nc) + 150;
215
216    authstr = av_malloc(len);
217    if (!authstr)
218        return NULL;
219    snprintf(authstr, len, "Authorization: Digest ");
220
221    /* TODO: Escape the quoted strings properly. */
222    av_strlcatf(authstr, len, "username=\"%s\"",   username);
223    av_strlcatf(authstr, len, ",realm=\"%s\"",     state->realm);
224    av_strlcatf(authstr, len, ",nonce=\"%s\"",     digest->nonce);
225    av_strlcatf(authstr, len, ",uri=\"%s\"",       uri);
226    av_strlcatf(authstr, len, ",response=\"%s\"",  response);
227
228    // we are violating the RFC and use "" because all others seem to do that too.
229    if (digest->algorithm[0])
230        av_strlcatf(authstr, len, ",algorithm=\"%s\"",  digest->algorithm);
231
232    if (digest->opaque[0])
233        av_strlcatf(authstr, len, ",opaque=\"%s\"", digest->opaque);
234    if (digest->qop[0]) {
235        av_strlcatf(authstr, len, ",qop=\"%s\"",    digest->qop);
236        av_strlcatf(authstr, len, ",cnonce=\"%s\"", cnonce);
237        av_strlcatf(authstr, len, ",nc=%s",         nc);
238    }
239
240    av_strlcatf(authstr, len, "\r\n");
241
242    return authstr;
243}
244
245char *ff_http_auth_create_response(HTTPAuthState *state, const char *auth,
246                                   const char *path, const char *method)
247{
248    char *authstr = NULL;
249
250    /* Clear the stale flag, we assume the auth is ok now. It is reset
251     * by the server headers if there's a new issue. */
252    state->stale = 0;
253    if (!auth || !strchr(auth, ':'))
254        return NULL;
255
256    if (state->auth_type == HTTP_AUTH_BASIC) {
257        int auth_b64_len, len;
258        char *ptr, *decoded_auth = ff_urldecode(auth);
259
260        if (!decoded_auth)
261            return NULL;
262
263        auth_b64_len = AV_BASE64_SIZE(strlen(decoded_auth));
264        len = auth_b64_len + 30;
265
266        authstr = av_malloc(len);
267        if (!authstr) {
268            av_free(decoded_auth);
269            return NULL;
270        }
271
272        snprintf(authstr, len, "Authorization: Basic ");
273        ptr = authstr + strlen(authstr);
274        av_base64_encode(ptr, auth_b64_len, decoded_auth, strlen(decoded_auth));
275        av_strlcat(ptr, "\r\n", len - (ptr - authstr));
276        av_free(decoded_auth);
277    } else if (state->auth_type == HTTP_AUTH_DIGEST) {
278        char *username = ff_urldecode(auth), *password;
279
280        if (!username)
281            return NULL;
282
283        if ((password = strchr(username, ':'))) {
284            *password++ = 0;
285            authstr = make_digest_auth(state, username, password, path, method);
286        }
287        av_free(username);
288    }
289    return authstr;
290}
291