xref: /openssl/crypto/http/http_lib.c (revision ab9d67ef) 
1 /*
2  * Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 #include <stdio.h>       /* for sscanf() */
11 #include <string.h>
12 #include <openssl/http.h>
13 #include <openssl/httperr.h>
14 #include <openssl/bio.h> /* for BIO_snprintf() */
15 #include <openssl/err.h>
16 #include "internal/cryptlib.h" /* for ossl_assert() */
17 
init_pstring(char ** pstr)18 static void init_pstring(char **pstr)
19 {
20     if (pstr != NULL) {
21         *pstr = NULL;
22     }
23 }
24 
copy_substring(char ** dest,const char * start,const char * end)25 static int copy_substring(char **dest, const char *start, const char *end)
26 {
27     return dest == NULL
28         || (*dest = OPENSSL_strndup(start, end - start)) != NULL;
29 }
30 
free_pstring(char ** pstr)31 static void free_pstring(char **pstr)
32 {
33     if (pstr != NULL) {
34         OPENSSL_free(*pstr);
35         *pstr = NULL;
36     }
37 }
38 
OSSL_parse_url(const char * url,char ** pscheme,char ** puser,char ** phost,char ** pport,int * pport_num,char ** ppath,char ** pquery,char ** pfrag)39 int OSSL_parse_url(const char *url, char **pscheme, char **puser, char **phost,
40                    char **pport, int *pport_num,
41                    char **ppath, char **pquery, char **pfrag)
42 {
43     const char *p, *tmp;
44     const char *scheme, *scheme_end;
45     const char *user, *user_end;
46     const char *host, *host_end;
47     const char *port, *port_end;
48     unsigned int portnum;
49     const char *path, *path_end;
50     const char *query, *query_end;
51     const char *frag, *frag_end;
52 
53     init_pstring(pscheme);
54     init_pstring(puser);
55     init_pstring(phost);
56     init_pstring(pport);
57     init_pstring(ppath);
58     init_pstring(pfrag);
59     init_pstring(pquery);
60 
61     if (url == NULL) {
62         ERR_raise(ERR_LIB_HTTP, ERR_R_PASSED_NULL_PARAMETER);
63         return 0;
64     }
65 
66     /* check for optional prefix "<scheme>://" */
67     scheme = scheme_end = url;
68     p = strstr(url, "://");
69     if (p == NULL) {
70         p = url;
71     } else {
72         scheme_end = p;
73         if (scheme_end == scheme)
74             goto parse_err;
75         p += strlen("://");
76     }
77 
78     /* parse optional "userinfo@" */
79     user = user_end = host = p;
80     host = strchr(p, '@');
81     if (host != NULL)
82         user_end = host++;
83     else
84         host = p;
85 
86     /* parse host name/address as far as needed here */
87     if (host[0] == '[') {
88         /* ipv6 literal, which may include ':' */
89         host_end = strchr(host + 1, ']');
90         if (host_end == NULL)
91             goto parse_err;
92         p = ++host_end;
93     } else {
94         /* look for start of optional port, path, query, or fragment */
95         host_end = strchr(host, ':');
96         if (host_end == NULL)
97             host_end = strchr(host, '/');
98         if (host_end == NULL)
99             host_end = strchr(host, '?');
100         if (host_end == NULL)
101             host_end = strchr(host, '#');
102         if (host_end == NULL) /* the remaining string is just the hostname */
103             host_end = host + strlen(host);
104         p = host_end;
105     }
106 
107     /* parse optional port specification starting with ':' */
108     port = "0"; /* default */
109     if (*p == ':')
110         port = ++p;
111     /* remaining port spec handling is also done for the default values */
112     /* make sure a decimal port number is given */
113     if (!sscanf(port, "%u", &portnum) || portnum > 65535) {
114         ERR_raise_data(ERR_LIB_HTTP, HTTP_R_INVALID_PORT_NUMBER, "%s", port);
115         goto err;
116     }
117     for (port_end = port; '0' <= *port_end && *port_end <= '9'; port_end++)
118         ;
119     if (port == p) /* port was given explicitly */
120         p += port_end - port;
121 
122     /* check for optional path starting with '/' or '?'. Else must start '#' */
123     path = p;
124     if (*path != '\0' && *path != '/' && *path != '?' && *path != '#') {
125         ERR_raise(ERR_LIB_HTTP, HTTP_R_INVALID_URL_PATH);
126         goto parse_err;
127     }
128     path_end = query = query_end = frag = frag_end = path + strlen(path);
129 
130     /* parse optional "?query" */
131     tmp = strchr(p, '?');
132     if (tmp != NULL) {
133         p = tmp;
134         if (pquery != NULL) {
135             path_end = p;
136             query = p + 1;
137         }
138     }
139 
140     /* parse optional "#fragment" */
141     tmp = strchr(p, '#');
142     if (tmp != NULL) {
143         if (query == path_end) /* we did not record a query component */
144             path_end = tmp;
145         query_end = tmp;
146         frag = tmp + 1;
147     }
148 
149     if (!copy_substring(pscheme, scheme, scheme_end)
150             || !copy_substring(phost, host, host_end)
151             || !copy_substring(pport, port, port_end)
152             || !copy_substring(puser, user, user_end)
153             || !copy_substring(pquery, query, query_end)
154             || !copy_substring(pfrag, frag, frag_end))
155         goto err;
156     if (pport_num != NULL)
157         *pport_num = (int)portnum;
158     if (*path == '/') {
159         if (!copy_substring(ppath, path, path_end))
160             goto err;
161     } else if (ppath != NULL) { /* must prepend '/' */
162         size_t buflen = 1 + path_end - path + 1;
163 
164         if ((*ppath = OPENSSL_malloc(buflen)) == NULL)
165             goto err;
166         BIO_snprintf(*ppath, buflen, "/%s", path);
167     }
168     return 1;
169 
170  parse_err:
171     ERR_raise(ERR_LIB_HTTP, HTTP_R_ERROR_PARSING_URL);
172 
173  err:
174     free_pstring(pscheme);
175     free_pstring(puser);
176     free_pstring(phost);
177     free_pstring(pport);
178     free_pstring(ppath);
179     free_pstring(pquery);
180     free_pstring(pfrag);
181     return 0;
182 }
183 
OSSL_HTTP_parse_url(const char * url,int * pssl,char ** puser,char ** phost,char ** pport,int * pport_num,char ** ppath,char ** pquery,char ** pfrag)184 int OSSL_HTTP_parse_url(const char *url, int *pssl, char **puser, char **phost,
185                         char **pport, int *pport_num,
186                         char **ppath, char **pquery, char **pfrag)
187 {
188     char *scheme, *port;
189     int ssl = 0, portnum;
190 
191     init_pstring(pport);
192     if (pssl != NULL)
193         *pssl = 0;
194     if (!OSSL_parse_url(url, &scheme, puser, phost, &port, pport_num,
195                         ppath, pquery, pfrag))
196         return 0;
197 
198     /* check for optional HTTP scheme "http[s]" */
199     if (strcmp(scheme, OSSL_HTTPS_NAME) == 0) {
200         ssl = 1;
201         if (pssl != NULL)
202             *pssl = ssl;
203     } else if (*scheme != '\0' && strcmp(scheme, OSSL_HTTP_NAME) != 0) {
204         ERR_raise(ERR_LIB_HTTP, HTTP_R_INVALID_URL_SCHEME);
205         OPENSSL_free(scheme);
206         OPENSSL_free(port);
207         goto err;
208     }
209     OPENSSL_free(scheme);
210 
211     if (strcmp(port, "0") == 0) {
212         /* set default port */
213         OPENSSL_free(port);
214         port = ssl ? OSSL_HTTPS_PORT : OSSL_HTTP_PORT;
215         if (!ossl_assert(sscanf(port, "%d", &portnum) == 1))
216             goto err;
217         if (pport_num != NULL)
218             *pport_num = portnum;
219         if (pport != NULL) {
220             *pport = OPENSSL_strdup(port);
221             if (*pport == NULL)
222                 goto err;
223         }
224     } else {
225         if (pport != NULL)
226             *pport = port;
227         else
228             OPENSSL_free(port);
229     }
230     return 1;
231 
232  err:
233     free_pstring(puser);
234     free_pstring(phost);
235     free_pstring(ppath);
236     free_pstring(pquery);
237     free_pstring(pfrag);
238     return 0;
239 }
240 
241 /* Respect no_proxy, taking default value from environment variable(s) */
use_proxy(const char * no_proxy,const char * server)242 static int use_proxy(const char *no_proxy, const char *server)
243 {
244     size_t sl;
245     const char *found = NULL;
246 
247     if (!ossl_assert(server != NULL))
248         return 0;
249     sl = strlen(server);
250 
251     /*
252      * using environment variable names, both lowercase and uppercase variants,
253      * compatible with other HTTP client implementations like wget, curl and git
254      */
255     if (no_proxy == NULL)
256         no_proxy = getenv("no_proxy");
257     if (no_proxy == NULL)
258         no_proxy = getenv(OPENSSL_NO_PROXY);
259 
260     if (no_proxy != NULL)
261         found = strstr(no_proxy, server);
262     while (found != NULL
263            && ((found != no_proxy && found[-1] != ' ' && found[-1] != ',')
264                || (found[sl] != '\0' && found[sl] != ' ' && found[sl] != ',')))
265         found = strstr(found + 1, server);
266     return found == NULL;
267 }
268 
269 /* Take default value from environment variable(s), respect no_proxy */
OSSL_HTTP_adapt_proxy(const char * proxy,const char * no_proxy,const char * server,int use_ssl)270 const char *OSSL_HTTP_adapt_proxy(const char *proxy, const char *no_proxy,
271                                   const char *server, int use_ssl)
272 {
273     /*
274      * using environment variable names, both lowercase and uppercase variants,
275      * compatible with other HTTP client implementations like wget, curl and git
276      */
277     if (proxy == NULL)
278         proxy = getenv(use_ssl ? "https_proxy" : "http_proxy");
279     if (proxy == NULL)
280         proxy = getenv(use_ssl ? OPENSSL_HTTP_PROXY :
281                        OPENSSL_HTTPS_PROXY);
282 
283     if (proxy == NULL || *proxy == '\0' || !use_proxy(no_proxy, server))
284         return NULL;
285     return proxy;
286 }
287