/src/libzip/lib/zip_source_winzip_aes_decode.c

Source
/*
  zip_source_winzip_aes_decode.c -- Winzip AES decryption routines
  Copyright (C) 2009-2024 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.
  The authors can be contacted at <info@libzip.org>

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  1. Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in
  the documentation and/or other materials provided with the
  distribution.
  3. The names of the authors may not be used to endorse or promote
  products derived from this software without specific prior
  written permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#include <stdlib.h>
#include <string.h>

#include "zipint.h"

#include "zip_crypto.h"

struct winzip_aes {
    char *password;
    zip_uint16_t encryption_method;

    zip_uint64_t data_length;
    zip_uint64_t current_position;

    zip_winzip_aes_t *aes_ctx;
    zip_error_t error;
};


static int decrypt_header(zip_source_t *src, struct winzip_aes *ctx);
static void winzip_aes_free(struct winzip_aes *);
static zip_int64_t winzip_aes_decrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd);
static struct winzip_aes *winzip_aes_new(zip_uint16_t encryption_method, const char *password, zip_error_t *error);


zip_source_t *zip_source_winzip_aes_decode(zip_t *za, zip_source_t *src, zip_uint16_t encryption_method, int flags, const char *password) {
    zip_source_t *s2;
    zip_stat_t st;
    zip_uint64_t aux_length;
    struct winzip_aes *ctx;

    if ((encryption_method != ZIP_EM_AES_128 && encryption_method != ZIP_EM_AES_192 && encryption_method != ZIP_EM_AES_256) || password == NULL || src == NULL) {
        zip_error_set(&za->error, ZIP_ER_INVAL, 0);
        return NULL;
    }
    if (flags & ZIP_CODEC_ENCODE) {
        zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
        return NULL;
    }

    if (zip_source_stat(src, &st) != 0) {
        zip_error_set_from_source(&za->error, src);
        return NULL;
    }

    aux_length = WINZIP_AES_PASSWORD_VERIFY_LENGTH + SALT_LENGTH(encryption_method) + HMAC_LENGTH;

    if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 || st.comp_size < aux_length) {
        zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
        return NULL;
    }

    if ((ctx = winzip_aes_new(encryption_method, password, &za->error)) == NULL) {
        return NULL;
    }

    ctx->data_length = st.comp_size - aux_length;

    if ((s2 = zip_source_layered(za, src, winzip_aes_decrypt, ctx)) == NULL) {
        winzip_aes_free(ctx);
        return NULL;
    }

    return s2;
}


static int decrypt_header(zip_source_t *src, struct winzip_aes *ctx) {
    zip_uint8_t header[WINZIP_AES_MAX_HEADER_LENGTH];
    zip_uint8_t password_verification[WINZIP_AES_PASSWORD_VERIFY_LENGTH];
    unsigned int headerlen;
    zip_int64_t n;

    headerlen = WINZIP_AES_PASSWORD_VERIFY_LENGTH + SALT_LENGTH(ctx->encryption_method);
    if ((n = zip_source_read(src, header, headerlen)) < 0) {
        zip_error_set_from_source(&ctx->error, src);
        return -1;
    }

    if (n != headerlen) {
        zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
        return -1;
    }

    if ((ctx->aes_ctx = _zip_winzip_aes_new((zip_uint8_t *)ctx->password, strlen(ctx->password), header, ctx->encryption_method, password_verification, &ctx->error)) == NULL) {
        return -1;
    }
    if (memcmp(password_verification, header + SALT_LENGTH(ctx->encryption_method), WINZIP_AES_PASSWORD_VERIFY_LENGTH) != 0) {
        _zip_winzip_aes_free(ctx->aes_ctx);
        ctx->aes_ctx = NULL;
        zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
        return -1;
    }
    return 0;
}


static bool verify_hmac(zip_source_t *src, struct winzip_aes *ctx) {
    unsigned char computed[ZIP_CRYPTO_SHA1_LENGTH], from_file[HMAC_LENGTH];
    if (zip_source_read(src, from_file, HMAC_LENGTH) < HMAC_LENGTH) {
        zip_error_set_from_source(&ctx->error, src);
        return false;
    }

    if (!_zip_winzip_aes_finish(ctx->aes_ctx, computed)) {
        zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);
        return false;
    }
    _zip_winzip_aes_free(ctx->aes_ctx);
    ctx->aes_ctx = NULL;

    if (memcmp(from_file, computed, HMAC_LENGTH) != 0) {
        zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
        return false;
    }

    return true;
}


static zip_int64_t winzip_aes_decrypt(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
    struct winzip_aes *ctx;
    zip_int64_t n;

    ctx = (struct winzip_aes *)ud;

    switch (cmd) {
    case ZIP_SOURCE_OPEN:
        if (decrypt_header(src, ctx) < 0) {
            return -1;
        }
        ctx->current_position = 0;
        return 0;

    case ZIP_SOURCE_READ:
        if (len > ctx->data_length - ctx->current_position) {
            len = ctx->data_length - ctx->current_position;
        }

        if (len == 0) {
            if (!verify_hmac(src, ctx)) {
                return -1;
            }
            return 0;
        }

        if ((n = zip_source_read(src, data, len)) < 0) {
            zip_error_set_from_source(&ctx->error, src);
            return -1;
        }
        ctx->current_position += (zip_uint64_t)n;

        if (!_zip_winzip_aes_decrypt(ctx->aes_ctx, (zip_uint8_t *)data, (zip_uint64_t)n)) {
            zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);
            return -1;
        }

        return n;

    case ZIP_SOURCE_CLOSE:
        return 0;

    case ZIP_SOURCE_STAT: {
        zip_stat_t *st;

        st = (zip_stat_t *)data;

        st->encryption_method = ZIP_EM_NONE;
        st->valid |= ZIP_STAT_ENCRYPTION_METHOD;
        if (st->valid & ZIP_STAT_COMP_SIZE) {
            st->comp_size -= 12 + SALT_LENGTH(ctx->encryption_method);
        }

        return 0;
    }

    case ZIP_SOURCE_SUPPORTS:
        return zip_source_make_command_bitmap(ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, ZIP_SOURCE_SUPPORTS_REOPEN, -1);

    case ZIP_SOURCE_ERROR:
        return zip_error_to_data(&ctx->error, data, len);

    case ZIP_SOURCE_FREE:
        winzip_aes_free(ctx);
        return 0;

    default:
        return zip_source_pass_to_lower_layer(src, data, len, cmd);
    }
}


static void winzip_aes_free(struct winzip_aes *ctx) {
    if (ctx == NULL) {
        return;
    }

    _zip_crypto_clear(ctx->password, strlen(ctx->password));
    free(ctx->password);
    zip_error_fini(&ctx->error);
    _zip_winzip_aes_free(ctx->aes_ctx);
    free(ctx);
}


static struct winzip_aes *winzip_aes_new(zip_uint16_t encryption_method, const char *password, zip_error_t *error) {
    struct winzip_aes *ctx;

    if ((ctx = (struct winzip_aes *)malloc(sizeof(*ctx))) == NULL) {
        zip_error_set(error, ZIP_ER_MEMORY, 0);
        return NULL;
    }

    if ((ctx->password = strdup(password)) == NULL) {
        zip_error_set(error, ZIP_ER_MEMORY, 0);
        free(ctx);
        return NULL;
    }

    ctx->encryption_method = encryption_method;
    ctx->aes_ctx = NULL;

    zip_error_init(&ctx->error);

    return ctx;
}

Coverage Report

Created: 2026-03-31 07:05

Line	Count	Source
1		/*
2		zip_source_winzip_aes_decode.c -- Winzip AES decryption routines
3		Copyright (C) 2009-2024 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 <info@libzip.org>
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
38		#include "zipint.h"
39
40		#include "zip_crypto.h"
41
42		struct winzip_aes {
43		char *password;
44		zip_uint16_t encryption_method;
45
46		zip_uint64_t data_length;
47		zip_uint64_t current_position;
48
49		zip_winzip_aes_t *aes_ctx;
50		zip_error_t error;
51		};
52
53
54		static int decrypt_header(zip_source_t src, struct winzip_aes ctx);
55		static void winzip_aes_free(struct winzip_aes *);
56		static zip_int64_t winzip_aes_decrypt(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd);
57		static struct winzip_aes winzip_aes_new(zip_uint16_t encryption_method, const char password, zip_error_t *error);
58
59
60	559	zip_source_t zip_source_winzip_aes_decode(zip_t za, zip_source_t src, zip_uint16_t encryption_method, int flags, const char password) {
61	559	zip_source_t *s2;
62	559	zip_stat_t st;
63	559	zip_uint64_t aux_length;
64	559	struct winzip_aes *ctx;
65
66	559	if ((encryption_method != ZIP_EM_AES_128 && encryption_method != ZIP_EM_AES_192 && encryption_method != ZIP_EM_AES_256) \|\| password == NULL \|\| src == NULL) {
67	0	zip_error_set(&za->error, ZIP_ER_INVAL, 0);
68	0	return NULL;
69	0	}
70	559	if (flags & ZIP_CODEC_ENCODE) {
71	0	zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
72	0	return NULL;
73	0	}
74
75	559	if (zip_source_stat(src, &st) != 0) {
76	0	zip_error_set_from_source(&za->error, src);
77	0	return NULL;
78	0	}
79
80	559	aux_length = WINZIP_AES_PASSWORD_VERIFY_LENGTH + SALT_LENGTH(encryption_method) + HMAC_LENGTH;
81
82	559	if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 \|\| st.comp_size < aux_length) {
83	15	zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
84	15	return NULL;
85	15	}
86
87	544	if ((ctx = winzip_aes_new(encryption_method, password, &za->error)) == NULL) {
88	0	return NULL;
89	0	}
90
91	544	ctx->data_length = st.comp_size - aux_length;
92
93	544	if ((s2 = zip_source_layered(za, src, winzip_aes_decrypt, ctx)) == NULL) {
94	0	winzip_aes_free(ctx);
95	0	return NULL;
96	0	}
97
98	544	return s2;
99	544	}
100
101
102	484	static int decrypt_header(zip_source_t src, struct winzip_aes ctx) {
103	484	zip_uint8_t header[WINZIP_AES_MAX_HEADER_LENGTH];
104	484	zip_uint8_t password_verification[WINZIP_AES_PASSWORD_VERIFY_LENGTH];
105	484	unsigned int headerlen;
106	484	zip_int64_t n;
107
108	484	headerlen = WINZIP_AES_PASSWORD_VERIFY_LENGTH + SALT_LENGTH(ctx->encryption_method);
109	484	if ((n = zip_source_read(src, header, headerlen)) < 0) {
110	29	zip_error_set_from_source(&ctx->error, src);
111	29	return -1;
112	29	}
113
114	455	if (n != headerlen) {
115	25	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
116	25	return -1;
117	25	}
118
119	430	if ((ctx->aes_ctx = _zip_winzip_aes_new((zip_uint8_t *)ctx->password, strlen(ctx->password), header, ctx->encryption_method, password_verification, &ctx->error)) == NULL) {
120	0	return -1;
121	0	}
122	430	if (memcmp(password_verification, header + SALT_LENGTH(ctx->encryption_method), WINZIP_AES_PASSWORD_VERIFY_LENGTH) != 0) {
123	90	_zip_winzip_aes_free(ctx->aes_ctx);
124	90	ctx->aes_ctx = NULL;
125	90	zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
126	90	return -1;
127	90	}
128	340	return 0;
129	430	}
130
131
132	124	static bool verify_hmac(zip_source_t src, struct winzip_aes ctx) {
133	124	unsigned char computed[ZIP_CRYPTO_SHA1_LENGTH], from_file[HMAC_LENGTH];
134	124	if (zip_source_read(src, from_file, HMAC_LENGTH) < HMAC_LENGTH) {
135	19	zip_error_set_from_source(&ctx->error, src);
136	19	return false;
137	19	}
138
139	105	if (!_zip_winzip_aes_finish(ctx->aes_ctx, computed)) {
140	0	zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);
141	0	return false;
142	0	}
143	105	_zip_winzip_aes_free(ctx->aes_ctx);
144	105	ctx->aes_ctx = NULL;
145
146	105	if (memcmp(from_file, computed, HMAC_LENGTH) != 0) {
147	90	zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
148	90	return false;
149	90	}
150
151	15	return true;
152	105	}
153
154
155	4.48k	static zip_int64_t winzip_aes_decrypt(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
156	4.48k	struct winzip_aes *ctx;
157	4.48k	zip_int64_t n;
158
159	4.48k	ctx = (struct winzip_aes *)ud;
160
161	4.48k	switch (cmd) {
162	484	case ZIP_SOURCE_OPEN:
163	484	if (decrypt_header(src, ctx) < 0) {
164	144	return -1;
165	144	}
166	340	ctx->current_position = 0;
167	340	return 0;
168
169	1.82k	case ZIP_SOURCE_READ:
170	1.82k	if (len > ctx->data_length - ctx->current_position) {
171	284	len = ctx->data_length - ctx->current_position;
172	284	}
173
174	1.82k	if (len == 0) {
175	124	if (!verify_hmac(src, ctx)) {
176	109	return -1;
177	109	}
178	15	return 0;
179	124	}
180
181	1.70k	if ((n = zip_source_read(src, data, len)) < 0) {
182	209	zip_error_set_from_source(&ctx->error, src);
183	209	return -1;
184	209	}
185	1.49k	ctx->current_position += (zip_uint64_t)n;
186
187	1.49k	if (!_zip_winzip_aes_decrypt(ctx->aes_ctx, (zip_uint8_t *)data, (zip_uint64_t)n)) {
188	0	zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);
189	0	return -1;
190	0	}
191
192	1.49k	return n;
193
194	340	case ZIP_SOURCE_CLOSE:
195	340	return 0;
196
197	280	case ZIP_SOURCE_STAT: {
198	280	zip_stat_t *st;
199
200	280	st = (zip_stat_t *)data;
201
202	280	st->encryption_method = ZIP_EM_NONE;
203	280	st->valid \|= ZIP_STAT_ENCRYPTION_METHOD;
204	280	if (st->valid & ZIP_STAT_COMP_SIZE) {
205	280	st->comp_size -= 12 + SALT_LENGTH(ctx->encryption_method);
206	280	}
207
208	280	return 0;
209	1.49k	}
210
211	544	case ZIP_SOURCE_SUPPORTS:
212	544	return zip_source_make_command_bitmap(ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, ZIP_SOURCE_SUPPORTS_REOPEN, -1);
213
214	462	case ZIP_SOURCE_ERROR:
215	462	return zip_error_to_data(&ctx->error, data, len);
216
217	544	case ZIP_SOURCE_FREE:
218	544	winzip_aes_free(ctx);
219	544	return 0;
220
221	0	default:
222	0	return zip_source_pass_to_lower_layer(src, data, len, cmd);
223	4.48k	}
224	4.48k	}
225
226
227	544	static void winzip_aes_free(struct winzip_aes *ctx) {
228	544	if (ctx == NULL) {
229	0	return;
230	0	}
231
232	544	_zip_crypto_clear(ctx->password, strlen(ctx->password));
233	544	free(ctx->password);
234	544	zip_error_fini(&ctx->error);
235	544	_zip_winzip_aes_free(ctx->aes_ctx);
236	544	free(ctx);
237	544	}
238
239
240	544	static struct winzip_aes winzip_aes_new(zip_uint16_t encryption_method, const char password, zip_error_t *error) {
241	544	struct winzip_aes *ctx;
242
243	544	if ((ctx = (struct winzip_aes )malloc(sizeof(ctx))) == NULL) {
244	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
245	0	return NULL;
246	0	}
247
248	544	if ((ctx->password = strdup(password)) == NULL) {
249	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
250	0	free(ctx);
251	0	return NULL;
252	0	}
253
254	544	ctx->encryption_method = encryption_method;
255	544	ctx->aes_ctx = NULL;
256
257	544	zip_error_init(&ctx->error);
258
259	544	return ctx;
260	544	}