1 /*-
2 * Copyright (c) 2014 Michihiro NAKAJIMA
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "archive_platform.h"
27
28 #ifdef HAVE_ERRNO_H
29 #include <errno.h>
30 #endif
31 #include "archive_read_private.h"
32
33 static void
add_passphrase_to_tail(struct archive_read * a,struct archive_read_passphrase * p)34 add_passphrase_to_tail(struct archive_read *a,
35 struct archive_read_passphrase *p)
36 {
37 *a->passphrases.last = p;
38 a->passphrases.last = &p->next;
39 p->next = NULL;
40 }
41
42 static struct archive_read_passphrase *
remove_passphrases_from_head(struct archive_read * a)43 remove_passphrases_from_head(struct archive_read *a)
44 {
45 struct archive_read_passphrase *p;
46
47 p = a->passphrases.first;
48 if (p != NULL)
49 a->passphrases.first = p->next;
50 return (p);
51 }
52
53 static void
insert_passphrase_to_head(struct archive_read * a,struct archive_read_passphrase * p)54 insert_passphrase_to_head(struct archive_read *a,
55 struct archive_read_passphrase *p)
56 {
57 p->next = a->passphrases.first;
58 a->passphrases.first = p;
59 if (&a->passphrases.first == a->passphrases.last) {
60 a->passphrases.last = &p->next;
61 p->next = NULL;
62 }
63 }
64
65 static struct archive_read_passphrase *
new_read_passphrase(struct archive_read * a,const char * passphrase)66 new_read_passphrase(struct archive_read *a, const char *passphrase)
67 {
68 struct archive_read_passphrase *p;
69
70 p = malloc(sizeof(*p));
71 if (p == NULL) {
72 archive_set_error(&a->archive, ENOMEM,
73 "Can't allocate memory");
74 return (NULL);
75 }
76 p->passphrase = strdup(passphrase);
77 if (p->passphrase == NULL) {
78 free(p);
79 archive_set_error(&a->archive, ENOMEM,
80 "Can't allocate memory");
81 return (NULL);
82 }
83 return (p);
84 }
85
86 int
archive_read_add_passphrase(struct archive * _a,const char * passphrase)87 archive_read_add_passphrase(struct archive *_a, const char *passphrase)
88 {
89 struct archive_read *a = (struct archive_read *)_a;
90 struct archive_read_passphrase *p;
91
92 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
93 "archive_read_add_passphrase");
94
95 if (passphrase == NULL || passphrase[0] == '\0') {
96 archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
97 "Empty passphrase is unacceptable");
98 return (ARCHIVE_FAILED);
99 }
100
101 p = new_read_passphrase(a, passphrase);
102 if (p == NULL)
103 return (ARCHIVE_FATAL);
104 add_passphrase_to_tail(a, p);
105
106 return (ARCHIVE_OK);
107 }
108
109 int
archive_read_set_passphrase_callback(struct archive * _a,void * client_data,archive_passphrase_callback * cb)110 archive_read_set_passphrase_callback(struct archive *_a, void *client_data,
111 archive_passphrase_callback *cb)
112 {
113 struct archive_read *a = (struct archive_read *)_a;
114
115 archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
116 "archive_read_set_passphrase_callback");
117
118 a->passphrases.callback = cb;
119 a->passphrases.client_data = client_data;
120 return (ARCHIVE_OK);
121 }
122
123 /*
124 * Call this in advance when you start to get a passphrase for decryption
125 * for a entry.
126 */
127 void
__archive_read_reset_passphrase(struct archive_read * a)128 __archive_read_reset_passphrase(struct archive_read *a)
129 {
130
131 a->passphrases.candidate = -1;
132 }
133
134 /*
135 * Get a passphrase for decryption.
136 */
137 const char *
__archive_read_next_passphrase(struct archive_read * a)138 __archive_read_next_passphrase(struct archive_read *a)
139 {
140 struct archive_read_passphrase *p;
141 const char *passphrase;
142
143 if (a->passphrases.candidate < 0) {
144 /* Count out how many passphrases we have. */
145 int cnt = 0;
146
147 for (p = a->passphrases.first; p != NULL; p = p->next)
148 cnt++;
149 a->passphrases.candidate = cnt;
150 p = a->passphrases.first;
151 } else if (a->passphrases.candidate > 1) {
152 /* Rotate a passphrase list. */
153 a->passphrases.candidate--;
154 p = remove_passphrases_from_head(a);
155 add_passphrase_to_tail(a, p);
156 /* Pick a new passphrase candidate up. */
157 p = a->passphrases.first;
158 } else if (a->passphrases.candidate == 1) {
159 /* This case is that all candidates failed to decrypt. */
160 a->passphrases.candidate = 0;
161 if (a->passphrases.first->next != NULL) {
162 /* Rotate a passphrase list. */
163 p = remove_passphrases_from_head(a);
164 add_passphrase_to_tail(a, p);
165 }
166 p = NULL;
167 } else /* There is no passphrase candidate. */
168 p = NULL;
169
170 if (p != NULL)
171 passphrase = p->passphrase;
172 else if (a->passphrases.callback != NULL) {
173 /* Get a passphrase through a call-back function
174 * since we tried all passphrases out or we don't
175 * have it. */
176 passphrase = a->passphrases.callback(&a->archive,
177 a->passphrases.client_data);
178 if (passphrase != NULL) {
179 p = new_read_passphrase(a, passphrase);
180 if (p == NULL)
181 return (NULL);
182 insert_passphrase_to_head(a, p);
183 a->passphrases.candidate = 1;
184 }
185 } else
186 passphrase = NULL;
187
188 return (passphrase);
189 }
190