2 zip_source_winzip_aes.c -- Winzip AES de/encryption routines
3 Copyright (C) 2009-2016 Dieter Baron and Thomas Klausner
5 This file is part of libzip, a library to manipulate ZIP archives.
6 The authors can be contacted at <libzip@nih.at>
8 Redistribution and use in source and binary forms, with or without
9 modification, are permitted provided that the following conditions
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
17 3. The names of the authors may not be used to endorse or promote
18 products derived from this software without specific prior
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.
40 #include "gladman-fcrypt.h"
42 #define MAX_HEADER_LENGTH (16+PWD_VER_LENGTH)
43 #define HMAC_LENGTH 10
45 static unsigned int salt_length[] = { 0, 8, 12, 16 };
51 zip_uint64_t data_length;
52 zip_uint64_t current_position;
54 fcrypt_ctx fcrypt_ctx;
59 static int decrypt_header(zip_source_t *src, struct winzip_aes *ctx);
60 static void winzip_aes_free(struct winzip_aes *);
61 static zip_int64_t winzip_aes_decrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd);
62 static struct winzip_aes * winzip_aes_new(unsigned int mode, const char *password);
66 zip_source_winzip_aes_decode(zip_t *za, zip_source_t *src, zip_uint16_t em, int flags, const char *password)
69 unsigned int mode = 0;
71 zip_uint64_t aux_length;
72 struct winzip_aes *ctx;
86 if (password == NULL || src == NULL || mode == 0) {
87 zip_error_set(&za->error, ZIP_ER_INVAL, 0);
90 if (flags & ZIP_CODEC_ENCODE) {
91 zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
95 if (strlen(password) > UINT_MAX) {
96 zip_error_set(&za->error, ZIP_ER_INVAL, 0); /* TODO: better error code? (password too long) */
100 if (zip_source_stat(src, &st) != 0) {
101 _zip_error_set_from_source(&za->error, src);
105 aux_length = PWD_VER_LENGTH + salt_length[mode] + HMAC_LENGTH;
107 if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 || st.comp_size < aux_length) {
108 zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
112 if ((ctx = winzip_aes_new(mode, password)) == NULL) {
113 zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
117 ctx->data_length = st.comp_size - aux_length;
119 if ((s2 = zip_source_layered(za, src, winzip_aes_decrypt, ctx)) == NULL) {
120 winzip_aes_free(ctx);
129 decrypt_header(zip_source_t *src, struct winzip_aes *ctx)
131 zip_uint8_t header[MAX_HEADER_LENGTH];
132 zip_uint8_t password_verification[PWD_VER_LENGTH];
133 unsigned int headerlen;
136 headerlen = PWD_VER_LENGTH + salt_length[ctx->mode];
137 if ((n=zip_source_read(src, header, headerlen)) < 0) {
138 _zip_error_set_from_source(&ctx->error, src);
142 if (n != headerlen) {
143 zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
147 if (_zip_fcrypt_init(ctx->mode, (unsigned char *)ctx->password, (unsigned int)strlen(ctx->password), header, password_verification, &ctx->fcrypt_ctx) != 0) {
148 zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
151 if (memcmp(password_verification, header + salt_length[ctx->mode], PWD_VER_LENGTH) != 0) {
152 zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
160 verify_hmac(zip_source_t *src, struct winzip_aes *ctx)
162 unsigned char computed[HMAC_LENGTH], from_file[HMAC_LENGTH];
163 if (zip_source_read(src, from_file, HMAC_LENGTH) < HMAC_LENGTH) {
164 _zip_error_set_from_source(&ctx->error, src);
168 _zip_fcrypt_end(computed, &ctx->fcrypt_ctx);
170 if (memcmp(from_file, computed, HMAC_LENGTH) != 0) {
171 zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
180 winzip_aes_decrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
182 struct winzip_aes *ctx;
184 zip_uint64_t total, offset;
186 ctx = (struct winzip_aes *)ud;
189 case ZIP_SOURCE_OPEN:
190 if (decrypt_header(src, ctx) < 0) {
193 ctx->current_position = 0;
196 case ZIP_SOURCE_READ:
197 if (len > ctx->data_length - ctx->current_position) {
198 len = ctx->data_length - ctx->current_position;
202 if (!verify_hmac(src, ctx)) {
208 if ((n=zip_source_read(src, data, len)) < 0) {
209 _zip_error_set_from_source(&ctx->error, src);
212 ctx->current_position += (zip_uint64_t)n;
214 total = (zip_uint64_t)n;
215 for (offset = 0; offset < total; offset += ZIP_MIN(total - offset, UINT_MAX)) {
216 _zip_fcrypt_decrypt((zip_uint8_t *)data + offset, (unsigned int)ZIP_MIN(total - offset, UINT_MAX), &ctx->fcrypt_ctx);
221 case ZIP_SOURCE_CLOSE:
224 case ZIP_SOURCE_STAT:
228 st = (zip_stat_t *)data;
230 st->encryption_method = ZIP_EM_NONE;
231 st->valid |= ZIP_STAT_ENCRYPTION_METHOD;
232 if (st->valid & ZIP_STAT_COMP_SIZE) {
233 st->comp_size -= 12 + salt_length[ctx->mode];
239 case ZIP_SOURCE_SUPPORTS:
240 return zip_source_make_command_bitmap(ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, -1);
242 case ZIP_SOURCE_ERROR:
243 return zip_error_to_data(&ctx->error, data, len);
245 case ZIP_SOURCE_FREE:
246 winzip_aes_free(ctx);
250 zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
257 winzip_aes_free(struct winzip_aes *ctx)
263 _zip_crypto_clear(&ctx->fcrypt_ctx, sizeof(ctx->fcrypt_ctx));
264 _zip_crypto_clear(ctx->password, strlen(ctx->password));
266 zip_error_fini(&ctx->error);
271 static struct winzip_aes *
272 winzip_aes_new(unsigned int mode, const char *password) {
273 struct winzip_aes *ctx;
275 if ((ctx = (struct winzip_aes *)malloc(sizeof(*ctx))) == NULL) {
279 if ((ctx->password = strdup(password)) == NULL) {
286 zip_error_init(&ctx->error);