archive_read_add_passphrase.c revision 305188 
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__FBSDID("$FreeBSD: stable/11/contrib/libarchive/libarchive/archive_read_add_passphrase.c 305188 2016-09-01 07:53:59Z mm $");
28
29#ifdef HAVE_ERRNO_H
30#include <errno.h>
31#endif
32#include "archive_read_private.h"
33
34static void
35add_passphrase_to_tail(struct archive_read *a,
36    struct archive_read_passphrase *p)
37{
38	*a->passphrases.last = p;
39	a->passphrases.last = &p->next;
40	p->next = NULL;
41}
42
43static struct archive_read_passphrase *
44remove_passphrases_from_head(struct archive_read *a)
45{
46	struct archive_read_passphrase *p;
47
48	p = a->passphrases.first;
49	if (p != NULL)
50		a->passphrases.first = p->next;
51	return (p);
52}
53
54static void
55insert_passphrase_to_head(struct archive_read *a,
56    struct archive_read_passphrase *p)
57{
58	p->next = a->passphrases.first;
59	a->passphrases.first = p;
60}
61
62static struct archive_read_passphrase *
63new_read_passphrase(struct archive_read *a, const char *passphrase)
64{
65	struct archive_read_passphrase *p;
66
67	p = malloc(sizeof(*p));
68	if (p == NULL) {
69		archive_set_error(&a->archive, ENOMEM,
70		    "Can't allocate memory");
71		return (NULL);
72	}
73	p->passphrase = strdup(passphrase);
74	if (p->passphrase == NULL) {
75		free(p);
76		archive_set_error(&a->archive, ENOMEM,
77		    "Can't allocate memory");
78		return (NULL);
79	}
80	return (p);
81}
82
83int
84archive_read_add_passphrase(struct archive *_a, const char *passphrase)
85{
86	struct archive_read *a = (struct archive_read *)_a;
87	struct archive_read_passphrase *p;
88
89	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
90		"archive_read_add_passphrase");
91
92	if (passphrase == NULL || passphrase[0] == '\0') {
93		archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
94		    "Empty passphrase is unacceptable");
95		return (ARCHIVE_FAILED);
96	}
97
98	p = new_read_passphrase(a, passphrase);
99	if (p == NULL)
100		return (ARCHIVE_FATAL);
101	add_passphrase_to_tail(a, p);
102
103	return (ARCHIVE_OK);
104}
105
106int
107archive_read_set_passphrase_callback(struct archive *_a, void *client_data,
108    archive_passphrase_callback *cb)
109{
110	struct archive_read *a = (struct archive_read *)_a;
111
112	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
113		"archive_read_set_passphrase_callback");
114
115	a->passphrases.callback = cb;
116	a->passphrases.client_data = client_data;
117	return (ARCHIVE_OK);
118}
119
120/*
121 * Call this in advance when you start to get a passphrase for decryption
122 * for a entry.
123 */
124void
125__archive_read_reset_passphrase(struct archive_read *a)
126{
127
128	a->passphrases.candidate = -1;
129}
130
131/*
132 * Get a passphrase for decryption.
133 */
134const char *
135__archive_read_next_passphrase(struct archive_read *a)
136{
137	struct archive_read_passphrase *p;
138	const char *passphrase;
139
140	if (a->passphrases.candidate < 0) {
141		/* Count out how many passphrases we have. */
142		int cnt = 0;
143
144		for (p = a->passphrases.first; p != NULL; p = p->next)
145			cnt++;
146		a->passphrases.candidate = cnt;
147		p = a->passphrases.first;
148	} else if (a->passphrases.candidate > 1) {
149		/* Rotate a passphrase list. */
150		a->passphrases.candidate--;
151		p = remove_passphrases_from_head(a);
152		add_passphrase_to_tail(a, p);
153		/* Pick a new passphrase candidate up. */
154		p = a->passphrases.first;
155	} else if (a->passphrases.candidate == 1) {
156		/* This case is that all candidates failed to decrypt. */
157		a->passphrases.candidate = 0;
158		if (a->passphrases.first->next != NULL) {
159			/* Rotate a passphrase list. */
160			p = remove_passphrases_from_head(a);
161			add_passphrase_to_tail(a, p);
162		}
163		p = NULL;
164	} else  /* There is no passphrase candidate. */
165		p = NULL;
166
167	if (p != NULL)
168		passphrase = p->passphrase;
169	else if (a->passphrases.callback != NULL) {
170		/* Get a passphrase through a call-back function
171		 * since we tried all passphrases out or we don't
172		 * have it. */
173		passphrase = a->passphrases.callback(&a->archive,
174		    a->passphrases.client_data);
175		if (passphrase != NULL) {
176			p = new_read_passphrase(a, passphrase);
177			if (p == NULL)
178				return (NULL);
179			insert_passphrase_to_head(a, p);
180			a->passphrases.candidate = 1;
181		}
182	} else
183		passphrase = NULL;
184
185	return (passphrase);
186}
187