1 /*
2 * Copyright (C) 1996-2021 The Squid Software Foundation and contributors
3 *
4 * Squid software is distributed under GPLv2+ license and includes
5 * contributions from numerous individuals and organizations.
6 * Please see the COPYING and CONTRIBUTORS files for details.
7 */
8
9 /*
10 * AUTHOR: Robert Collins.
11 * Based on ncsa_auth.c by Arjan de Vet <Arjan.deVet@adv.iae.nl>
12 *
13 * Example digest auth text backend for Squid, based on the original
14 * proxy_auth code from client_side.c, written by
15 * Jon Thackray <jrmt@uk.gdscorp.com>.
16 *
17 * - comment lines are possible and should start with a '#';
18 * - empty or blank lines are possible;
19 * - file format is username:plaintext or username:realm:HA1
20 *
21 * To build a directory integrated backend, you need to be able to
22 * calculate the HA1 returned to squid. To avoid storing a plaintext
23 * password you can calculate MD5(username:realm:password) when the
24 * user changes their password, and store the tuple username:realm:HA1.
25 * then find the matching username:realm when squid asks for the
26 * HA1.
27 *
28 * This implementation could be improved by using such a triple for
29 * the file format. However storing such a triple does little to
30 * improve security: If compromised the username:realm:HA1 combination
31 * is "plaintext equivalent" - for the purposes of digest authentication
32 * they allow the user access. Password synchronization is not tackled
33 * by digest - just preventing on the wire compromise.
34 *
35 * Copyright (c) 2003 Robert Collins <robertc@squid-cache.org>
36 */
37
38 #include "squid.h"
39 #include "auth/digest/file/text_backend.h"
40
41 static hash_table *hash = NULL;
42 static HASHFREE my_free;
43 static char *passwdfile = NULL;
44 static int ha1mode = 0;
45 static time_t change_time = 0;
46
47 typedef struct _user_data {
48 hash_link hash;
49 char *passwd;
50 char *ha1;
51 } user_data;
52
53 static void
my_free(void * p)54 my_free(void *p)
55 {
56 user_data *u = static_cast<user_data*>(p);
57 xfree(u->hash.key);
58 xfree(u->passwd);
59 xfree(u);
60 }
61
62 static void
read_passwd_file(const char * passwordFile,int isHa1Mode)63 read_passwd_file(const char *passwordFile, int isHa1Mode)
64 {
65 char buf[8192];
66 user_data *u;
67 char *user;
68 char *passwd;
69 char *ha1 = NULL;
70 char *realm;
71
72 if (hash != NULL) {
73 hashFreeItems(hash, my_free);
74 }
75 /* initial setup */
76 hash = hash_create((HASHCMP *) strcmp, 7921, hash_string);
77 if (NULL == hash) {
78 fprintf(stderr, "digest_file_auth: cannot create hash table\n");
79 exit(1);
80 }
81 FILE *f = fopen(passwordFile, "r");
82 if (!f) {
83 int xerrno = errno;
84 fprintf(stderr, "digest_file_auth: cannot open password file: %s\n", xstrerr(xerrno));
85 exit(1);
86 }
87 unsigned int lineCount = 0;
88 while (fgets(buf, sizeof(buf), f) != NULL) {
89 ++lineCount;
90 if ((buf[0] == '#') || (buf[0] == ' ') || (buf[0] == '\t') ||
91 (buf[0] == '\n'))
92 continue;
93 user = strtok(buf, ":\n");
94 if (!user) {
95 fprintf(stderr, "digest_file_auth: missing user name at line %u in '%s'\n", lineCount, passwordFile);
96 continue;
97 }
98 realm = strtok(NULL, ":\n");
99 passwd = strtok(NULL, ":\n");
100 if (!passwd) {
101 passwd = realm;
102 realm = NULL;
103 }
104 if ((strlen(user) > 0) && passwd) {
105 if (strncmp(passwd, "{HHA1}", 6) == 0) {
106 ha1 = passwd + 6;
107 passwd = NULL;
108 } else if (isHa1Mode) {
109 ha1 = passwd;
110 passwd = NULL;
111 }
112 if (ha1 && strlen(ha1) != 32) {
113 /* We cannot accept plaintext passwords when using HA1 encoding,
114 * as the passwords may be output to cache.log if debugging is on.
115 */
116 fprintf(stderr, "digest_file_auth: ignoring invalid password for %s\n", user);
117 continue;
118 }
119 u = static_cast<user_data*>(xcalloc(1, sizeof(*u)));
120 if (realm) {
121 int len = strlen(user) + strlen(realm) + 2;
122 u->hash.key = xmalloc(len);
123 snprintf(static_cast<char*>(u->hash.key), len, "%s:%s", user, realm);
124 } else {
125 u->hash.key = xstrdup(user);
126 }
127 if (ha1)
128 u->ha1 = xstrdup(ha1);
129 else
130 u->passwd = xstrdup(passwd);
131 hash_join(hash, &u->hash);
132 }
133 }
134 fclose(f);
135 }
136
137 /* replace when changing the backend */
138 void
TextArguments(int argc,char ** argv)139 TextArguments(int argc, char **argv)
140 {
141 struct stat sb;
142 if (argc == 2)
143 passwdfile = argv[1];
144 if ((argc == 3) && !strcmp("-c", argv[1])) {
145 ha1mode = 1;
146 passwdfile = argv[2];
147 }
148 if (!passwdfile) {
149 fprintf(stderr, "Usage: digest_file_auth [OPTIONS] <passwordfile>\n");
150 fprintf(stderr, " -c accept digest hashed passwords rather than plaintext in passwordfile\n");
151 exit(1);
152 }
153 if (stat(passwdfile, &sb) != 0) {
154 fprintf(stderr, "cannot stat %s\n", passwdfile);
155 exit(1);
156 }
157 }
158
159 static const user_data *
GetPassword(RequestData * requestData)160 GetPassword(RequestData * requestData)
161 {
162 user_data *u;
163 struct stat sb;
164 char buf[256];
165 int len;
166 if (stat(passwdfile, &sb) == 0) {
167 if (sb.st_mtime != change_time) {
168 read_passwd_file(passwdfile, ha1mode);
169 change_time = sb.st_mtime;
170 }
171 }
172 if (!hash)
173 return NULL;
174 len = snprintf(buf, sizeof(buf), "%s:%s", requestData->user, requestData->realm);
175 if (len >= static_cast<int>(sizeof(buf)))
176 return NULL;
177 u = (user_data*)hash_lookup(hash, buf);
178 if (u)
179 return u;
180 u = (user_data*)hash_lookup(hash, requestData->user);
181 return u;
182 }
183
184 void
TextHHA1(RequestData * requestData)185 TextHHA1(RequestData * requestData)
186 {
187 const user_data *u = GetPassword(requestData);
188 if (!u) {
189 requestData->error = -1;
190 return;
191 }
192 if (u->ha1) {
193 xstrncpy(requestData->HHA1, u->ha1, sizeof(requestData->HHA1));
194 } else {
195 HASH HA1;
196 DigestCalcHA1("md5", requestData->user, requestData->realm, u->passwd, NULL, NULL, HA1, requestData->HHA1);
197 }
198 }
199
200