1 /*
2 * External backend for file-backed passwords
3 * Copyright (c) 2021, Patrick Steinhardt <ps@pks.im>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "includes.h"
10
11 #include "utils/common.h"
12 #include "ext_password_i.h"
13
14
15 /**
16 * Data structure for the file-backed password backend.
17 */
18 struct ext_password_file_data {
19 char *path; /* path of the password file */
20 };
21
22
23 /**
24 * ext_password_file_init - Initialize file-backed password backend
25 * @params: Parameters passed by the user.
26 * Returns: Pointer to the initialized backend.
27 *
28 * This function initializes a new file-backed password backend. The user is
29 * expected to initialize this backend with the parameters being the path of
30 * the file that contains the passwords.
31 */
ext_password_file_init(const char * params)32 static void * ext_password_file_init(const char *params)
33 {
34 struct ext_password_file_data *data;
35
36 if (!params) {
37 wpa_printf(MSG_ERROR, "EXT PW FILE: no path given");
38 return NULL;
39 }
40
41 data = os_zalloc(sizeof(*data));
42 if (!data)
43 return NULL;
44
45 data->path = os_strdup(params);
46 if (!data->path) {
47 os_free(data);
48 return NULL;
49 }
50
51 return data;
52 }
53
54
55 /**
56 * ext_password_file_deinit - Deinitialize file-backed password backend
57 * @ctx: The file-backed password backend
58 *
59 * This function frees all data associated with the file-backed password
60 * backend.
61 */
ext_password_file_deinit(void * ctx)62 static void ext_password_file_deinit(void *ctx)
63 {
64 struct ext_password_file_data *data = ctx;
65
66 str_clear_free(data->path);
67 os_free(data);
68 }
69
70 /**
71 * ext_password_file_get - Retrieve password from the file-backed password backend
72 * @ctx: The file-backed password backend
73 * @name: Name of the password to retrieve
74 * Returns: Buffer containing the password if one was found or %NULL.
75 *
76 * This function tries to find a password identified by name in the password
77 * file. The password is expected to be stored in `NAME=PASSWORD` format.
78 * Comments and empty lines in the file are ignored. Invalid lines will cause
79 * an error message, but will not cause the function to fail.
80 */
ext_password_file_get(void * ctx,const char * name)81 static struct wpabuf * ext_password_file_get(void *ctx, const char *name)
82 {
83 struct ext_password_file_data *data = ctx;
84 struct wpabuf *password = NULL;
85 char buf[512], *pos;
86 size_t name_len;
87 int line = 0;
88 FILE *f;
89
90 f = fopen(data->path, "r");
91 if (!f) {
92 wpa_printf(MSG_ERROR,
93 "EXT PW FILE: could not open file '%s': %s",
94 data->path, strerror(errno));
95 return NULL;
96 }
97
98 name_len = os_strlen(name);
99
100 wpa_printf(MSG_DEBUG, "EXT PW FILE: get(%s)", name);
101
102 while ((pos = fgets(buf, sizeof(buf), f))) {
103 char *sep;
104
105 line++;
106
107 /* Strip newline characters */
108 pos[strcspn(pos, "\r\n")] = 0;
109
110 /* Skip comments and empty lines */
111 if (*pos == '#' || *pos == '\0')
112 continue;
113
114 sep = os_strchr(pos, '=');
115 if (!sep) {
116 wpa_printf(MSG_ERROR, "Invalid password line %d.",
117 line);
118 continue;
119 }
120
121 if (!sep[1]) {
122 wpa_printf(MSG_ERROR, "No password for line %d.", line);
123 continue;
124
125 }
126
127 if (name_len != (size_t) (sep - pos) ||
128 os_strncmp(name, pos, sep - pos) != 0)
129 continue;
130
131 password = wpabuf_alloc_copy(sep + 1, os_strlen(sep + 1));
132 goto done;
133 }
134
135 wpa_printf(MSG_ERROR, "Password for '%s' was not found.", name);
136
137 done:
138 forced_memzero(buf, sizeof(buf));
139 fclose(f);
140 return password;
141 }
142
143
144 const struct ext_password_backend ext_password_file = {
145 .name = "file",
146 .init = ext_password_file_init,
147 .deinit = ext_password_file_deinit,
148 .get = ext_password_file_get,
149 };
150