/src/libzip/lib/zip_source_pkware_decode.c

Source
/*
  zip_source_pkware_decode.c -- Traditional PKWARE 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"

struct trad_pkware {
    char *password;
    zip_pkware_keys_t keys;
    zip_error_t error;
};


static int decrypt_header(zip_source_t *, struct trad_pkware *);
static zip_int64_t pkware_decrypt(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
static struct trad_pkware *trad_pkware_new(const char *password, zip_error_t *error);
static void trad_pkware_free(struct trad_pkware *);


zip_source_t *zip_source_pkware_decode(zip_t *za, zip_source_t *src, zip_uint16_t em, int flags, const char *password) {
    struct trad_pkware *ctx;
    zip_source_t *s2;
    zip_stat_t st;

    if (password == NULL || src == NULL || em != ZIP_EM_TRAD_PKWARE) {
        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;
    }

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

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

    if ((s2 = zip_source_layered(za, src, pkware_decrypt, ctx)) == NULL) {
        trad_pkware_free(ctx);
        return NULL;
    }

    return s2;
}


static int decrypt_header(zip_source_t *src, struct trad_pkware *ctx) {
    zip_uint8_t header[ZIP_CRYPTO_PKWARE_HEADERLEN];
    zip_stat_t st;
    zip_dostime_t dostime;
    zip_int64_t n;

    if ((n = zip_source_read(src, header, ZIP_CRYPTO_PKWARE_HEADERLEN)) < 0) {
        zip_error_set_from_source(&ctx->error, src);
        return -1;
    }

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

    _zip_pkware_decrypt(&ctx->keys, header, header, ZIP_CRYPTO_PKWARE_HEADERLEN);

    if (zip_source_stat(src, &st) < 0 || (st.valid & ZIP_STAT_CRC) == 0) {
        /* skip password validation */
        return 0;
    }

    if (zip_source_get_dos_time(src, &dostime) <= 0) {
        if ((st.valid & ZIP_STAT_MTIME) == 0) {
            /* no date available, skip password validation */
            return 0;
        }

        if (_zip_u2d_time(st.mtime, &dostime, &ctx->error) < 0) {
            return -1;
        }
    }

    /*
       password verification - two ways:
       - mtime - InfoZIP way, to avoid computing complete CRC before encrypting data
       - CRC - old PKWare way
    */
    if (header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == dostime.time >> 8 || header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == st.crc >> 24) {
        return 0;
    }
    else {
        zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
        return -1;
    }
}


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

    ctx = (struct trad_pkware *)ud;

    switch (cmd) {
    case ZIP_SOURCE_OPEN:
        _zip_pkware_keys_reset(&ctx->keys);
        _zip_pkware_decrypt(&ctx->keys, NULL, (const zip_uint8_t *)ctx->password, strlen(ctx->password));
        if (decrypt_header(src, ctx) < 0) {
            return -1;
        }
        return 0;

    case ZIP_SOURCE_READ:
        if ((n = zip_source_read(src, data, len)) < 0) {
            zip_error_set_from_source(&ctx->error, src);
            return -1;
        }

        _zip_pkware_decrypt(&ctx->keys, (zip_uint8_t *)data, (zip_uint8_t *)data, (zip_uint64_t)n);
        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) {
            if (st->comp_size < ZIP_CRYPTO_PKWARE_HEADERLEN) {
                zip_error_set(&ctx->error, ZIP_ER_DATA_LENGTH, 0);
                return -1;
            }
            st->comp_size -= ZIP_CRYPTO_PKWARE_HEADERLEN;
        }

        return 0;
    }

    case ZIP_SOURCE_SUPPORTS:
        return zip_source_make_command_bitmap(ZIP_SOURCE_AT_EOF, 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:
        trad_pkware_free(ctx);
        return 0;

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


static struct trad_pkware *trad_pkware_new(const char *password, zip_error_t *error) {
    struct trad_pkware *ctx;

    if ((ctx = (struct trad_pkware *)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;
    }

    zip_error_init(&ctx->error);

    return ctx;
}


static void trad_pkware_free(struct trad_pkware *ctx) {
    if (ctx == NULL) {
        return;
    }

    _zip_crypto_clear(ctx->password, strlen(ctx->password));
    free(ctx->password);
    free(ctx);
}

Coverage Report

Created: 2026-08-31 06:55

Line	Count	Source
1		/*
2		zip_source_pkware_decode.c -- Traditional PKWARE 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		struct trad_pkware {
41		char *password;
42		zip_pkware_keys_t keys;
43		zip_error_t error;
44		};
45
46
47		static int decrypt_header(zip_source_t , struct trad_pkware );
48		static zip_int64_t pkware_decrypt(zip_source_t , void , void *, zip_uint64_t, zip_source_cmd_t);
49		static struct trad_pkware trad_pkware_new(const char password, zip_error_t *error);
50		static void trad_pkware_free(struct trad_pkware *);
51
52
53	9.68k	zip_source_t zip_source_pkware_decode(zip_t za, zip_source_t src, zip_uint16_t em, int flags, const char password) {
54	9.68k	struct trad_pkware *ctx;
55	9.68k	zip_source_t *s2;
56	9.68k	zip_stat_t st;
57
58	9.68k	if (password == NULL \|\| src == NULL \|\| em != ZIP_EM_TRAD_PKWARE) {
59	0	zip_error_set(&za->error, ZIP_ER_INVAL, 0);
60	0	return NULL;
61	0	}
62	9.68k	if (flags & ZIP_CODEC_ENCODE) {
63	0	zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
64	0	return NULL;
65	0	}
66
67	9.68k	if (zip_source_stat(src, &st) != 0) {
68	0	zip_error_set_from_source(&za->error, src);
69	0	return NULL;
70	0	}
71
72	9.68k	if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 \|\| st.comp_size < ZIP_CRYPTO_PKWARE_HEADERLEN) {
73	757	zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
74	757	return NULL;
75	757	}
76
77	8.92k	if ((ctx = trad_pkware_new(password, &za->error)) == NULL) {
78	0	return NULL;
79	0	}
80
81	8.92k	if ((s2 = zip_source_layered(za, src, pkware_decrypt, ctx)) == NULL) {
82	0	trad_pkware_free(ctx);
83	0	return NULL;
84	0	}
85
86	8.92k	return s2;
87	8.92k	}
88
89
90	5.65k	static int decrypt_header(zip_source_t src, struct trad_pkware ctx) {
91	5.65k	zip_uint8_t header[ZIP_CRYPTO_PKWARE_HEADERLEN];
92	5.65k	zip_stat_t st;
93	5.65k	zip_dostime_t dostime;
94	5.65k	zip_int64_t n;
95
96	5.65k	if ((n = zip_source_read(src, header, ZIP_CRYPTO_PKWARE_HEADERLEN)) < 0) {
97	414	zip_error_set_from_source(&ctx->error, src);
98	414	return -1;
99	414	}
100
101	5.23k	if (n != ZIP_CRYPTO_PKWARE_HEADERLEN) {
102	276	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
103	276	return -1;
104	276	}
105
106	4.96k	_zip_pkware_decrypt(&ctx->keys, header, header, ZIP_CRYPTO_PKWARE_HEADERLEN);
107
108	4.96k	if (zip_source_stat(src, &st) < 0 \|\| (st.valid & ZIP_STAT_CRC) == 0) {
109		/* skip password validation */
110	0	return 0;
111	0	}
112
113	4.96k	if (zip_source_get_dos_time(src, &dostime) <= 0) {
114	0	if ((st.valid & ZIP_STAT_MTIME) == 0) {
115		/* no date available, skip password validation */
116	0	return 0;
117	0	}
118
119	0	if (_zip_u2d_time(st.mtime, &dostime, &ctx->error) < 0) {
120	0	return -1;
121	0	}
122	0	}
123
124		/*
125		password verification - two ways:
126		- mtime - InfoZIP way, to avoid computing complete CRC before encrypting data
127		- CRC - old PKWare way
128		*/
129	4.96k	if (header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == dostime.time >> 8 \|\| header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == st.crc >> 24) {
130	4.23k	return 0;
131	4.23k	}
132	731	else {
133	731	zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
134	731	return -1;
135	731	}
136	4.96k	}
137
138
139	46.1k	static zip_int64_t pkware_decrypt(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
140	46.1k	struct trad_pkware *ctx;
141	46.1k	zip_int64_t n;
142
143	46.1k	ctx = (struct trad_pkware *)ud;
144
145	46.1k	switch (cmd) {
146	5.65k	case ZIP_SOURCE_OPEN:
147	5.65k	_zip_pkware_keys_reset(&ctx->keys);
148	5.65k	_zip_pkware_decrypt(&ctx->keys, NULL, (const zip_uint8_t *)ctx->password, strlen(ctx->password));
149	5.65k	if (decrypt_header(src, ctx) < 0) {
150	1.42k	return -1;
151	1.42k	}
152	4.23k	return 0;
153
154	8.30k	case ZIP_SOURCE_READ:
155	8.30k	if ((n = zip_source_read(src, data, len)) < 0) {
156	1.01k	zip_error_set_from_source(&ctx->error, src);
157	1.01k	return -1;
158	1.01k	}
159
160	7.29k	_zip_pkware_decrypt(&ctx->keys, (zip_uint8_t )data, (zip_uint8_t )data, (zip_uint64_t)n);
161	7.29k	return n;
162
163	4.23k	case ZIP_SOURCE_CLOSE:
164	4.23k	return 0;
165
166	7.47k	case ZIP_SOURCE_STAT: {
167	7.47k	zip_stat_t *st;
168
169	7.47k	st = (zip_stat_t *)data;
170
171	7.47k	st->encryption_method = ZIP_EM_NONE;
172	7.47k	st->valid \|= ZIP_STAT_ENCRYPTION_METHOD;
173	7.47k	if (st->valid & ZIP_STAT_COMP_SIZE) {
174	7.47k	if (st->comp_size < ZIP_CRYPTO_PKWARE_HEADERLEN) {
175	0	zip_error_set(&ctx->error, ZIP_ER_DATA_LENGTH, 0);
176	0	return -1;
177	0	}
178	7.47k	st->comp_size -= ZIP_CRYPTO_PKWARE_HEADERLEN;
179	7.47k	}
180
181	7.47k	return 0;
182	7.47k	}
183
184	8.92k	case ZIP_SOURCE_SUPPORTS:
185	8.92k	return zip_source_make_command_bitmap(ZIP_SOURCE_AT_EOF, ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, ZIP_SOURCE_SUPPORTS_REOPEN, -1);
186
187	2.43k	case ZIP_SOURCE_ERROR:
188	2.43k	return zip_error_to_data(&ctx->error, data, len);
189
190	8.92k	case ZIP_SOURCE_FREE:
191	8.92k	trad_pkware_free(ctx);
192	8.92k	return 0;
193
194	222	default:
195	222	return zip_source_pass_to_lower_layer(src, data, len, cmd);
196	46.1k	}
197	46.1k	}
198
199
200	8.92k	static struct trad_pkware trad_pkware_new(const char password, zip_error_t *error) {
201	8.92k	struct trad_pkware *ctx;
202
203	8.92k	if ((ctx = (struct trad_pkware )malloc(sizeof(ctx))) == NULL) {
204	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
205	0	return NULL;
206	0	}
207
208	8.92k	if ((ctx->password = strdup(password)) == NULL) {
209	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
210	0	free(ctx);
211	0	return NULL;
212	0	}
213
214	8.92k	zip_error_init(&ctx->error);
215
216	8.92k	return ctx;
217	8.92k	}
218
219
220	8.92k	static void trad_pkware_free(struct trad_pkware *ctx) {
221	8.92k	if (ctx == NULL) {
222	0	return;
223	0	}
224
225	8.92k	_zip_crypto_clear(ctx->password, strlen(ctx->password));
226	8.92k	free(ctx->password);
227	8.92k	free(ctx);
228	8.92k	}