xref: /PHP-7.0/ext/zip/lib/zip_source_crc.c (revision 478f119a)
1 /*
2   zip_source_crc.c -- pass-through source that calculates CRC32 and size
3   Copyright (c) 2009-2017 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 #include <string.h>
37 #include <limits.h>
38 
39 #include "zipint.h"
40 
41 struct crc_context {
42     int validate; /* whether to check CRC on EOF and return error on mismatch */
43     int crc_complete; /* whether CRC was computed for complete file */
44     zip_error_t error;
45     zip_uint64_t size;
46     zip_uint64_t position; /* current reading position */
47     zip_uint64_t crc_position; /* how far we've computed the CRC */
48     zip_uint32_t crc;
49 };
50 
51 static zip_int64_t crc_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
52 
53 
54 zip_source_t *
zip_source_crc(zip_t * za,zip_source_t * src,int validate)55 zip_source_crc(zip_t *za, zip_source_t *src, int validate)
56 {
57     struct crc_context *ctx;
58 
59     if (src == NULL) {
60 	zip_error_set(&za->error, ZIP_ER_INVAL, 0);
61 	return NULL;
62     }
63 
64     if ((ctx=(struct crc_context *)malloc(sizeof(*ctx))) == NULL) {
65 	zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
66 	return NULL;
67     }
68 
69     zip_error_init(&ctx->error);
70     ctx->validate = validate;
71     ctx->crc_complete = 0;
72     ctx->crc_position = 0;
73     ctx->crc = (zip_uint32_t)crc32(0, NULL, 0);
74     ctx->size = 0;
75 
76     return zip_source_layered(za, src, crc_read, ctx);
77 }
78 
79 
80 static zip_int64_t
crc_read(zip_source_t * src,void * _ctx,void * data,zip_uint64_t len,zip_source_cmd_t cmd)81 crc_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
82 {
83     struct crc_context *ctx;
84     zip_int64_t n;
85 
86     ctx = (struct crc_context *)_ctx;
87 
88     switch (cmd) {
89         case ZIP_SOURCE_OPEN:
90             ctx->position = 0;
91             return 0;
92 
93         case ZIP_SOURCE_READ:
94             if ((n = zip_source_read(src, data, len)) < 0) {
95                 _zip_error_set_from_source(&ctx->error, src);
96                 return -1;
97             }
98 
99             if (n == 0) {
100                 if (ctx->crc_position == ctx->position) {
101                     ctx->crc_complete = 1;
102                     ctx->size = ctx->position;
103 
104                     if (ctx->validate) {
105                         struct zip_stat st;
106 
107                         if (zip_source_stat(src, &st) < 0) {
108                             _zip_error_set_from_source(&ctx->error, src);
109                             return -1;
110                         }
111 
112                         if ((st.valid & ZIP_STAT_CRC) && st.crc != ctx->crc) {
113                             zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
114                             return -1;
115                         }
116                         if ((st.valid & ZIP_STAT_SIZE) && st.size != ctx->size) {
117                             zip_error_set(&ctx->error, ZIP_ER_INCONS, 0);
118                             return -1;
119                         }
120                     }
121                 }
122             }
123             else if (!ctx->crc_complete && ctx->position <= ctx->crc_position) {
124 		zip_uint64_t i, nn;
125 
126 		for (i = ctx->crc_position - ctx->position; i < (zip_uint64_t)n; i += nn) {
127 		    nn = ZIP_MIN(UINT_MAX, (zip_uint64_t)n-i);
128 
129 		    ctx->crc = (zip_uint32_t)crc32(ctx->crc, (const Bytef *)data+i, (uInt)nn);
130                     ctx->crc_position += nn;
131 		}
132             }
133             ctx->position += (zip_uint64_t)n;
134             return n;
135 
136         case ZIP_SOURCE_CLOSE:
137             return 0;
138 
139         case ZIP_SOURCE_STAT:
140         {
141             zip_stat_t *st;
142 
143 	    st = (zip_stat_t *)data;
144 
145 	    if (ctx->crc_complete) {
146 		/* TODO: Set comp_size, comp_method, encryption_method?
147 		        After all, this only works for uncompressed data. */
148 		st->size = ctx->size;
149 		st->crc = ctx->crc;
150 		st->comp_size = ctx->size;
151 		st->comp_method = ZIP_CM_STORE;
152 		st->encryption_method = ZIP_EM_NONE;
153 		st->valid |= ZIP_STAT_SIZE|ZIP_STAT_CRC|ZIP_STAT_COMP_SIZE|ZIP_STAT_COMP_METHOD|ZIP_STAT_ENCRYPTION_METHOD;;
154 	    }
155             return 0;
156         }
157 
158         case ZIP_SOURCE_ERROR:
159             return zip_error_to_data(&ctx->error, data, len);
160 
161         case ZIP_SOURCE_FREE:
162             free(ctx);
163             return 0;
164 
165         case ZIP_SOURCE_SUPPORTS:
166         {
167             zip_int64_t mask = zip_source_supports(src);
168 
169             if (mask < 0) {
170                 _zip_error_set_from_source(&ctx->error, src);
171                 return -1;
172             }
173 
174             return mask & ~zip_source_make_command_bitmap(ZIP_SOURCE_BEGIN_WRITE, ZIP_SOURCE_COMMIT_WRITE, ZIP_SOURCE_ROLLBACK_WRITE, ZIP_SOURCE_SEEK_WRITE, ZIP_SOURCE_TELL_WRITE, ZIP_SOURCE_REMOVE, -1);
175         }
176 
177         case ZIP_SOURCE_SEEK:
178         {
179             zip_int64_t new_position;
180             zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);
181 
182 	    if (args == NULL) {
183 		return -1;
184 	    }
185             if (zip_source_seek(src, args->offset, args->whence) < 0 || (new_position = zip_source_tell(src)) < 0) {
186                 _zip_error_set_from_source(&ctx->error, src);
187                 return -1;
188             }
189 
190             ctx->position = (zip_uint64_t)new_position;
191 
192             return 0;
193         }
194 
195         case ZIP_SOURCE_TELL:
196             return (zip_int64_t)ctx->position;
197 
198         default:
199             zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
200             return -1;
201     }
202 }
203