"Fossies" - the Fresh Open Source Software Archive 
1 /*
2 zip_source_zip_new.c -- prepare data structures for zip_fopen/zip_source_zip
3 Copyright (C) 2012-2017 Dieter Baron and Thomas Klausner
4
5 This file is part of libzip, a library to manipulate ZIP archives.
6 The authors can be contacted at <libzip@nih.at>
7
8 Redistribution and use in source and binary forms, with or without
9 modification, are permitted provided that the following conditions
10 are met:
11 1. Redistributions of source code must retain the above copyright
12 notice, this list of conditions and the following disclaimer.
13 2. Redistributions in binary form must reproduce the above copyright
14 notice, this list of conditions and the following disclaimer in
15 the documentation and/or other materials provided with the
16 distribution.
17 3. The names of the authors may not be used to endorse or promote
18 products derived from this software without specific prior
19 written permission.
20
21 THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
22 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
29 IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
31 IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34
35 #include <stdlib.h>
36
37 #include "zipint.h"
38
39
40 zip_source_t *
41 _zip_source_zip_new(zip_t *za, zip_t *srcza, zip_uint64_t srcidx, zip_flags_t flags, zip_uint64_t start, zip_uint64_t len, const char *password) {
42 zip_source_t *src, *s2;
43 struct zip_stat st;
44 bool partial_data, needs_crc, needs_decrypt, needs_decompress;
45
46 if (za == NULL)
47 return NULL;
48
49 if (srcza == NULL || srcidx >= srcza->nentry) {
50 zip_error_set(&za->error, ZIP_ER_INVAL, 0);
51 return NULL;
52 }
53
54 if ((flags & ZIP_FL_UNCHANGED) == 0 && (ZIP_ENTRY_DATA_CHANGED(srcza->entry + srcidx) || srcza->entry[srcidx].deleted)) {
55 zip_error_set(&za->error, ZIP_ER_CHANGED, 0);
56 return NULL;
57 }
58
59 if (zip_stat_index(srcza, srcidx, flags | ZIP_FL_UNCHANGED, &st) < 0) {
60 zip_error_set(&za->error, ZIP_ER_INTERNAL, 0);
61 return NULL;
62 }
63
64 if (flags & ZIP_FL_ENCRYPTED)
65 flags |= ZIP_FL_COMPRESSED;
66
67 if ((start > 0 || len > 0) && (flags & ZIP_FL_COMPRESSED)) {
68 zip_error_set(&za->error, ZIP_ER_INVAL, 0);
69 return NULL;
70 }
71
72 /* overflow or past end of file */
73 if ((start > 0 || len > 0) && (start + len < start || start + len > st.size)) {
74 zip_error_set(&za->error, ZIP_ER_INVAL, 0);
75 return NULL;
76 }
77
78 if (len == 0) {
79 len = st.size - start;
80 }
81
82 partial_data = len < st.size;
83 needs_decrypt = ((flags & ZIP_FL_ENCRYPTED) == 0) && (st.encryption_method != ZIP_EM_NONE);
84 needs_decompress = ((flags & ZIP_FL_COMPRESSED) == 0) && (st.comp_method != ZIP_CM_STORE);
85 /* when reading the whole file, check for CRC errors */
86 needs_crc = ((flags & ZIP_FL_COMPRESSED) == 0 || st.comp_method == ZIP_CM_STORE) && !partial_data;
87
88 if (needs_decrypt) {
89 if (password == NULL) {
90 password = za->default_password;
91 }
92 if (password == NULL) {
93 zip_error_set(&za->error, ZIP_ER_NOPASSWD, 0);
94 return NULL;
95 }
96 }
97
98 if (st.comp_size == 0) {
99 return zip_source_buffer(za, NULL, 0, 0);
100 }
101
102 if (partial_data && !needs_decrypt && !needs_decompress) {
103 struct zip_stat st2;
104
105 st2.size = len;
106 st2.comp_size = len;
107 st2.comp_method = ZIP_CM_STORE;
108 st2.mtime = st.mtime;
109 st2.valid = ZIP_STAT_SIZE | ZIP_STAT_COMP_SIZE | ZIP_STAT_COMP_METHOD | ZIP_STAT_MTIME;
110
111 if ((src = _zip_source_window_new(srcza->src, start, len, &st2, 0, srcza, srcidx, &za->error)) == NULL) {
112 return NULL;
113 }
114 }
115 else {
116 zip_dirent_t *de;
117
118 if ((de = _zip_get_dirent(srcza, srcidx, flags, &za->error)) == NULL) {
119 return NULL;
120 }
121 if ((src = _zip_source_window_new(srcza->src, 0, st.comp_size, &st, (de->bitflags >> 1) & 3, srcza, srcidx, &za->error)) == NULL) {
122 return NULL;
123 }
124 }
125
126 if (_zip_source_set_source_archive(src, srcza) < 0) {
127 zip_source_free(src);
128 return NULL;
129 }
130
131 /* creating a layered source calls zip_keep() on the lower layer, so we free it */
132
133 if (needs_decrypt) {
134 zip_encryption_implementation enc_impl;
135
136 if ((enc_impl = _zip_get_encryption_implementation(st.encryption_method, ZIP_CODEC_DECODE)) == NULL) {
137 zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
138 return NULL;
139 }
140
141 s2 = enc_impl(za, src, st.encryption_method, 0, password);
142 zip_source_free(src);
143 if (s2 == NULL) {
144 return NULL;
145 }
146 src = s2;
147 }
148 if (needs_decompress) {
149 s2 = zip_source_decompress(za, src, st.comp_method);
150 zip_source_free(src);
151 if (s2 == NULL) {
152 return NULL;
153 }
154 src = s2;
155 }
156 if (needs_crc) {
157 s2 = zip_source_crc(za, src, 1);
158 zip_source_free(src);
159 if (s2 == NULL) {
160 return NULL;
161 }
162 src = s2;
163 }
164
165 if (partial_data && (needs_decrypt || needs_decompress)) {
166 s2 = zip_source_window(za, src, start, len);
167 zip_source_free(src);
168 if (s2 == NULL) {
169 return NULL;
170 }
171 src = s2;
172 }
173
174 return src;
175 }
1.21_Source_vs_1.22_Source.