text_backend.cc
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1/*
2 * Copyright (C) 1996-2022 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"
40
41static hash_table *hash = nullptr;
43static char *passwdfile = nullptr;
44static int ha1mode = 0;
45static time_t change_time = 0;
46
47typedef struct _user_data {
49 char *passwd;
50 char *ha1;
52
53static void
54my_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
62static void
63read_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 = nullptr;
70 char *realm;
71
72 if (hash != nullptr) {
74 }
75 /* initial setup */
76 hash = hash_create((HASHCMP *) strcmp, 7921, hash_string);
77 if (nullptr == hash) {
78 fprintf(stderr, "digest_file_auth: cannot create hash table\n");
79 exit(EXIT_FAILURE);
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(EXIT_FAILURE);
86 }
87 unsigned int lineCount = 0;
88 while (fgets(buf, sizeof(buf), f) != nullptr) {
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(nullptr, ":\n");
99 passwd = strtok(nullptr, ":\n");
100 if (!passwd) {
101 passwd = realm;
102 realm = nullptr;
103 }
104 if ((strlen(user) > 0) && passwd) {
105 if (strncmp(passwd, "{HHA1}", 6) == 0) {
106 ha1 = passwd + 6;
107 passwd = nullptr;
108 } else if (isHa1Mode) {
109 ha1 = passwd;
110 passwd = nullptr;
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 */
138void
139TextArguments(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(EXIT_FAILURE);
152 }
153 if (stat(passwdfile, &sb) != 0) {
154 fprintf(stderr, "cannot stat %s\n", passwdfile);
155 exit(EXIT_FAILURE);
156 }
157}
158
159static const user_data *
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) {
169 change_time = sb.st_mtime;
170 }
171 }
172 if (!hash)
173 return nullptr;
174 len = snprintf(buf, sizeof(buf), "%s:%s", requestData->user, requestData->realm);
175 if (len >= static_cast<int>(sizeof(buf)))
176 return nullptr;
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
184void
185TextHHA1(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, nullptr, nullptr, HA1, requestData->HHA1);
197 }
198}
199
SQUIDCEXTERN hash_table * hash_create(HASHCMP *, int, HASHHASH *)
Definition: hash.cc:108
void HASHFREE(void *)
Definition: hash.h:12
SQUIDCEXTERN void hashFreeItems(hash_table *, HASHFREE *)
Definition: hash.cc:252
SQUIDCEXTERN void hash_join(hash_table *, hash_link *)
Definition: hash.cc:131
int HASHCMP(const void *, const void *)
Definition: hash.h:13
SQUIDCEXTERN HASHHASH hash_string
Definition: hash.h:45
SQUIDCEXTERN hash_link * hash_lookup(hash_table *, const void *)
Definition: hash.cc:146
#define xfree
#define xstrdup
#define xmalloc
void DigestCalcHA1(const char *pszAlg, const char *pszUserName, const char *pszRealm, const char *pszPassword, const char *pszNonce, const char *pszCNonce, HASH HA1, HASHHEX SessionKey)
Definition: rfc2617.c:88
char HASH[HASHLEN]
Definition: rfc2617.h:31
static struct stat sb
Definition: squidclient.cc:71
hash_link hash
Definition: text_backend.cc:48
char * ha1
Definition: text_backend.cc:50
char * passwd
Definition: text_backend.cc:49
static hash_table * hash
Definition: text_backend.cc:41
static HASHFREE my_free
Definition: text_backend.cc:42
static int ha1mode
Definition: text_backend.cc:44
void TextArguments(int argc, char **argv)
void TextHHA1(RequestData *requestData)
static void read_passwd_file(const char *passwordFile, int isHa1Mode)
Definition: text_backend.cc:63
static char * passwdfile
Definition: text_backend.cc:43
static time_t change_time
Definition: text_backend.cc:45
static const user_data * GetPassword(RequestData *requestData)
struct _user_data user_data
void * xcalloc(size_t n, size_t sz)
Definition: xalloc.cc:71
const char * xstrerr(int error)
Definition: xstrerror.cc:83
char * xstrncpy(char *dst, const char *src, size_t n)
Definition: xstring.cc:37

 

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