1 /* wget.c - Simple downloader to get the resource file from a HTTP server
2 *
3 * Copyright 2016 Lipi C.H. Lee <lipisoft@gmail.com>
4 * Copyright 2021 Eric Molitor <eric@molitor.org>
5 *
6 * Relevant sources of information
7 * -------------------------------
8 * HTTP 1.1: https://www.rfc-editor.org/rfc/rfc7230
9 * Chunked Encoding: https://www.rfc-editor.org/rfc/rfc7230#section-4.1
10 * UTF-8 Encoded Header Values https://www.rfc-editor.org/rfc/rfc5987
11 *
12 * Test URLs
13 * ---------
14 * Chunked Encoding: https://jigsaw.w3.org/HTTP/ChunkedScript
15 * Redirect 301: https://jigsaw.w3.org/HTTP/300/301.html
16 * Redirect 302: https://jigsaw.w3.org/HTTP/300/302.html
17 * TLS 1.0: https://tls-v1-0.badssl.com:1010/
18 * TLS 1.1: https://tls-v1-1.badssl.com:1011/
19 * TLS 1.2: https://tls-v1-2.badssl.com:1012/
20 * TLS 1.3: https://tls13.1d.pw/
21 * Transfer Encoding [gzip|deflate]: https://jigsaw.w3.org/HTTP/TE/bar.txt
22 *
23 *
24 * todo: Add support for configurable TLS versions
25 * todo: Add support for ftp
26 * todo: Add support for Transfer Encoding (gzip|deflate)
27 * todo: Add support for RFC5987
28
29 USE_WGET(NEWTOY(wget, "<1>1(max-redirect)#<0=20d(debug)O(output-document):", TOYFLAG_USR|TOYFLAG_BIN))
30
31 config WGET
32 bool "wget"
33 default n
34 help
35 usage: wget [OPTIONS]... [URL]
36 --max-redirect maximum redirections allowed
37 -d, --debug print lots of debugging information
38 -O, --output-document=FILE specify output filename
39
40 examples:
41 wget http://www.example.com
42
43 config WGET_LIBTLS
44 bool "Enable HTTPS support for wget via LibTLS"
45 default n
46 depends on WGET && !WGET_OPENSSL
47 help
48 Enable HTTPS support for wget by linking to LibTLS.
49 Supports using libtls, libretls or libtls-bearssl.
50
51 config WGET_OPENSSL
52 bool "Enable HTTPS support for wget via OpenSSL"
53 default n
54 depends on WGET && !WGET_LIBTLS
55 help
56 Enable HTTPS support for wget by linking to OpenSSL.
57 */
58
59 #define FOR_wget
60 #include "toys.h"
61
62 #if CFG_WGET_LIBTLS
63 #define WGET_SSL 1
64 #include <tls.h>
65 #elif CFG_WGET_OPENSSL
66 #define WGET_SSL 1
67 #include <openssl/crypto.h>
68 #include <openssl/ssl.h>
69 #include <openssl/err.h>
70 #else
71 #define WGET_SSL 0
72 #endif
73
74 #define WGET_FILENAME "Content-Disposition: attachment; filename="
75 #define WGET_CHUNKED "transfer-encoding: chunked"
76 #define WGET_LOCATION "Location: "
77 #define WGET_LIBTLS_PROTOCOLS "tlsv1.2"
78
79 #define WGET_IS_HTTP (strncmp(TT.url, "http://", 7) == 0)
80 #define WGET_IS_HTTPS (WGET_SSL && (strncmp(TT.url, "https://", 8) == 0))
81
GLOBALS(char * filename;long redirects;int sock;char * url;struct tls * tls;)82 GLOBALS(
83 char *filename;
84 long redirects;
85
86 int sock;
87 char *url;
88 #if CFG_WGET_LIBTLS
89 struct tls *tls;
90 #elif CFG_WGET_OPENSSL
91 struct ssl_ctx_st *ctx;
92 struct ssl_st *ssl;
93 #endif
94 )
95
96 static char *wget_strncaseafter(char *haystack, char *needle)
97 {
98 char *result = strcasestr(haystack, needle);
99 if (result) result = result + strlen(needle);
100 return result;
101 }
102
103 // get http info in URL
wget_info(char * url,char ** host,char ** port,char ** path)104 static void wget_info(char *url, char **host, char **port, char **path)
105 {
106 *host = strafter(url, "://");
107 *path = strchr(*host, '/');
108
109 if ((*path = strchr(*host, '/'))) {
110 **path = '\0';
111 *path = *path + 1;
112 } else {
113 *path = "";
114 }
115
116 if ( *host[0] == '[' && strchr(*host, ']') ) { // IPv6
117 *port = strafter(*host, "]:");
118 *host = *host + 1;
119 strchr(*host, ']')[0] = '\0';
120 } else { // IPv4
121 if ((*port = strchr(*host, ':'))) {
122 **port = '\0';
123 *port = *port + 1;
124 }
125 }
126
127 if (!*port && WGET_IS_HTTP) *port = "80";
128 else if (!*port && WGET_IS_HTTPS) *port = "443";
129 else if (!*port) error_exit("unsupported protocol");
130 }
131
wget_connect(char * host,char * port)132 static void wget_connect(char *host, char *port)
133 {
134 if (WGET_IS_HTTP) {
135 struct addrinfo *a =
136 xgetaddrinfo(host, port, AF_UNSPEC, SOCK_STREAM, 0, 0);
137 TT.sock = xconnectany(a);
138 } else if (WGET_IS_HTTPS) {
139 #if CFG_WGET_LIBTLS
140 struct tls_config *cfg = NULL;
141 uint32_t protocols;
142 if ((TT.tls = tls_client()) == NULL)
143 error_exit("tls_client: %s", tls_error(TT.tls));
144 if ((cfg = tls_config_new()) == NULL)
145 error_exit("tls_config_new: %s", tls_config_error(cfg));
146 if (tls_config_parse_protocols(&protocols, WGET_LIBTLS_PROTOCOLS) != 0)
147 error_exit("tls_config_parse_protocols");
148 if (tls_config_set_protocols(cfg, protocols) != 0)
149 error_exit("tls_config_set_protocols: %s", tls_config_error(cfg));
150 if (tls_configure(TT.tls, cfg) != 0)
151 error_exit("tls_configure: %s", tls_error(TT.tls));
152 tls_config_free(cfg);
153
154 if (tls_connect(TT.tls, host, port) != 0)
155 error_exit("tls_connect: %s", tls_error(TT.tls));
156 #elif CFG_WGET_OPENSSL
157 SSL_library_init();
158 OpenSSL_add_all_algorithms();
159 SSL_load_error_strings();
160 ERR_load_crypto_strings();
161
162 TT.ctx = SSL_CTX_new(TLS_client_method());
163 if (!TT.ctx) error_exit("SSL_CTX_new");
164
165 struct addrinfo *a =
166 xgetaddrinfo(host, port, AF_UNSPEC, SOCK_STREAM, 0, 0);
167 TT.sock = xconnectany(a);
168
169 TT.ssl = SSL_new(TT.ctx);
170 if (!TT.ssl)
171 error_exit("SSL_new: %s", ERR_error_string(ERR_get_error(), NULL));
172
173 if (!SSL_set_tlsext_host_name(TT.ssl, host))
174 error_exit("SSL_set_tlsext_host_name: %s",
175 ERR_error_string(ERR_get_error(), NULL));
176
177 SSL_set_fd(TT.ssl, TT.sock);
178 if (SSL_connect(TT.ssl) == -1)
179 error_exit("SSL_set_fd: %s", ERR_error_string(ERR_get_error(), NULL));
180
181 if (FLAG(d)) printf("TLS: %s\n", SSL_get_cipher(TT.ssl));
182 #endif
183 } else error_exit("unsupported protocol");
184 }
185
wget_read(void * buf,size_t len)186 static size_t wget_read(void *buf, size_t len)
187 {
188 if (WGET_IS_HTTP) return xread(TT.sock, buf, len);
189 else if (WGET_IS_HTTPS) {
190 #if CFG_WGET_LIBTLS
191 ssize_t ret = tls_read(TT.tls, buf, len);
192 if (ret < 0) error_exit("tls_read: %s", tls_error(TT.tls));
193 return ret;
194 #elif CFG_WGET_OPENSSL
195 int ret = SSL_read(TT.ssl, buf, (int) len);
196 if (ret < 0)
197 error_exit("SSL_read: %s", ERR_error_string(ERR_get_error(), NULL));
198 return ret;
199 #endif
200 } else error_exit("unsupported protocol");
201 }
202
wget_write(void * buf,size_t len)203 static void wget_write(void *buf, size_t len)
204 {
205 if (WGET_IS_HTTP) {
206 xwrite(TT.sock, buf, len);
207 } else if (WGET_IS_HTTPS) {
208 #if CFG_WGET_LIBTLS
209 if (len != tls_write(TT.tls, buf, len))
210 error_exit("tls_write: %s", tls_error(TT.tls));
211 #elif CFG_WGET_OPENSSL
212 if (len != SSL_write(TT.ssl, buf, (int) len))
213 error_exit("SSL_write: %s", ERR_error_string(ERR_get_error(), NULL));
214 #endif
215 } else error_exit("unsupported protocol");
216 }
217
wget_close()218 static void wget_close()
219 {
220 if (TT.sock) {
221 xclose(TT.sock);
222 TT.sock = 0;
223 }
224
225 #if CFG_WGET_LIBTLS
226 if (TT.tls) {
227 tls_close(TT.tls);
228 tls_free(TT.tls);
229 TT.tls = NULL;
230 }
231 #elif CFG_WGET_OPENSSL
232 if (TT.ssl) {
233 SSL_shutdown(TT.ssl);
234 SSL_free(TT.ssl);
235 TT.ssl = NULL;
236 }
237
238 if (TT.ctx) {
239 SSL_CTX_free(TT.ctx);
240 TT.ctx = NULL;
241 }
242 #endif
243 }
244
wget_find_header(char * header,char * val)245 static char* wget_find_header(char *header, char *val) {
246 char *v= wget_strncaseafter(header, val);
247 return v;
248 }
249
wget_has_header(char * header,char * val)250 static int wget_has_header(char *header, char *val)
251 {
252 return wget_find_header(header, val) != NULL;
253 }
254
wget_redirect(char * header)255 static char *wget_redirect(char *header)
256 {
257 char *redir = wget_find_header(header, WGET_LOCATION);
258 if (!redir) error_exit("could not parse redirect URL");
259 return xstrndup(redir, stridx(redir, '\r'));
260 }
261
wget_filename(char * header,char * path)262 static char *wget_filename(char *header, char *path)
263 {
264 char *f = wget_find_header(header, WGET_FILENAME);
265 if (f) strchr(f, '\r')[0] = '\0';
266
267 if (!f && strchr(path, '/')) f = getbasename(path);
268 if (!f || !(*f) ) f = "index.html";
269
270 return f;
271 }
272
wget_main(void)273 void wget_main(void)
274 {
275 long status = 0;
276 size_t len, c_len = 0;
277 int fd, chunked;
278 char *body, *index, *host, *port, *path;
279 char agent[] = "toybox wget/" TOYBOX_VERSION;
280
281 TT.url = xstrdup(toys.optargs[0]);
282
283 for (;status != 200; TT.redirects--) {
284 if (TT.redirects < 0) error_exit("Too many redirects");
285
286 wget_info(TT.url, &host, &port, &path);
287
288 sprintf(toybuf, "GET /%s HTTP/1.1\r\nHost: %s\r\n"
289 "User-Agent: %s\r\nConnection: close\r\n\r\n",
290 path, host, agent);
291 if (FLAG(d)) printf("--- Request\n%s", toybuf);
292
293 wget_connect(host, port);
294 wget_write(toybuf, strlen(toybuf));
295
296 // Greedily read the HTTP response until either complete or toybuf is full
297 index = toybuf;
298 while ((len = wget_read(index, sizeof(toybuf) - (index - toybuf))) > 0)
299 index += len;
300
301 //Process the response such that
302 // Valid ranges toybuf[0...index) valid length is (index - toybuf)
303 // Header ranges toybuf[0...body) header length strlen(toybuf)
304 // Remnant Body toybuf[body...index) valid remnant body length is len
305 //
306 // Per RFC7230 the header cannot contain a NUL octet so we NUL terminate at
307 // the footer of the header. This allows for normal string functions to be
308 // used when processing the header.
309 body = memmem(toybuf, index - toybuf, "\r\n\r\n", 4);
310 if (!body) error_exit("response header too large");
311 body[0] = '\0'; // NUL terminate the headers
312 body += 4; // Skip to the head of body
313 len = index - body; // Adjust len to be body length
314 if (FLAG(d)) printf("--- Response\n%s\n\n", toybuf);
315
316 status = strtol(strafter(toybuf, " "), NULL, 10);
317 if ((status == 301) || (status == 302)) {
318 free(TT.url);
319 TT.url = wget_redirect(toybuf);
320 wget_close();
321 } else if (status != 200) error_exit("response: %ld", status);
322 }
323
324 if (!FLAG(O)) {
325 TT.filename = wget_filename(toybuf, path);
326 if (!access(TT.filename, F_OK))
327 error_exit("%s already exists", TT.filename);
328 }
329 fd = xcreate(TT.filename, (O_WRONLY|O_CREAT|O_TRUNC), 0644);
330
331 chunked = wget_has_header(toybuf, WGET_CHUNKED);
332
333 // If chunked we offset the first buffer by 2 character, meaning it is
334 // pointing at half of the header boundary, aka '\r\n'. This simplifies
335 // parsing of the first c_len length by allowing the do while loop to fall
336 // through on the first iteration and parse the first c_len size.
337 if (chunked) {
338 len = len + 2;
339 memmove(toybuf, body - 2, len);
340 } else {
341 memmove(toybuf, body, len);
342 }
343
344 // len is the size remaining in toybuf
345 // c_len is the size of the remaining bytes in the current chunk
346 do {
347 if (chunked) {
348 if (c_len > 0) { // We have an incomplete c_len to write
349 if (len <= c_len) { // Buffer is less than the c_len so full write
350 xwrite(fd, toybuf, len);
351 c_len = c_len - len;
352 len = 0;
353 } else { // Buffer is larger than the c_len so partial write
354 xwrite(fd, toybuf, c_len);
355 len = len - c_len;
356 memmove(toybuf, toybuf + c_len, len);
357 c_len = 0;
358 }
359 }
360
361 // If len is less than 2 we can't validate the chunk boundary so fall
362 // through and go read more into toybuf.
363 if ((c_len == 0) && (len > 2)) {
364 char *c;
365 if (strncmp(toybuf, "\r\n", 2) != 0) error_exit("chunk boundary");
366
367 // If we can't find the end of the new chunk signature fall through and
368 // read more into toybuf.
369 c = memmem(toybuf + 2, len - 2, "\r\n",2);
370 if (c) {
371 c_len = strtol(toybuf + 2, NULL, 16);
372 if (c_len == 0) goto exit; // A c_len of zero means we are complete
373 len = len - (c - toybuf) - 2;
374 memmove(toybuf, c + 2, len);
375 }
376 }
377
378 if (len == sizeof(toybuf)) error_exit("chunk overflow");
379 } else {
380 xwrite(fd, toybuf, len);
381 len = 0;
382 }
383 } while ((len += wget_read(toybuf + len, sizeof(toybuf) - len)) > 0);
384
385 exit:
386 wget_close();
387 free(TT.url);
388 }
389