/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;

    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 ((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) {
            st->comp_size -= ZIP_CRYPTO_PKWARE_HEADERLEN;
        }

        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:
        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;
    }

    free(ctx->password);
    free(ctx);
}

Coverage Report

Created: 2026-02-14 06:48

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		zip_source_t *
54	5.48k	zip_source_pkware_decode(zip_t za, zip_source_t src, zip_uint16_t em, int flags, const char *password) {
55	5.48k	struct trad_pkware *ctx;
56	5.48k	zip_source_t *s2;
57
58	5.48k	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	5.48k	if (flags & ZIP_CODEC_ENCODE) {
63	0	zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
64	0	return NULL;
65	0	}
66
67	5.48k	if ((ctx = trad_pkware_new(password, &za->error)) == NULL) {
68	0	return NULL;
69	0	}
70
71	5.48k	if ((s2 = zip_source_layered(za, src, pkware_decrypt, ctx)) == NULL) {
72	0	trad_pkware_free(ctx);
73	0	return NULL;
74	0	}
75
76	5.48k	return s2;
77	5.48k	}
78
79
80		static int
81	4.27k	decrypt_header(zip_source_t src, struct trad_pkware ctx) {
82	4.27k	zip_uint8_t header[ZIP_CRYPTO_PKWARE_HEADERLEN];
83	4.27k	zip_stat_t st;
84	4.27k	zip_dostime_t dostime;
85	4.27k	zip_int64_t n;
86
87	4.27k	if ((n = zip_source_read(src, header, ZIP_CRYPTO_PKWARE_HEADERLEN)) < 0) {
88	721	zip_error_set_from_source(&ctx->error, src);
89	721	return -1;
90	721	}
91
92	3.55k	if (n != ZIP_CRYPTO_PKWARE_HEADERLEN) {
93	500	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
94	500	return -1;
95	500	}
96
97	3.05k	_zip_pkware_decrypt(&ctx->keys, header, header, ZIP_CRYPTO_PKWARE_HEADERLEN);
98
99	3.05k	if (zip_source_stat(src, &st) < 0 \|\| (st.valid & ZIP_STAT_CRC) == 0) {
100		/* skip password validation */
101	0	return 0;
102	0	}
103
104	3.05k	if (zip_source_get_dos_time(src, &dostime) <= 0) {
105	0	if ((st.valid & ZIP_STAT_MTIME) == 0) {
106		/* no date available, skip password validation */
107	0	return 0;
108	0	}
109
110	0	if (_zip_u2d_time(st.mtime, &dostime, &ctx->error) < 0) {
111	0	return -1;
112	0	}
113	0	}
114
115		/*
116		password verification - two ways:
117		- mtime - InfoZIP way, to avoid computing complete CRC before encrypting data
118		- CRC - old PKWare way
119		*/
120	3.05k	if (header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == dostime.time >> 8
121	2.16k	\|\| header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == st.crc >> 24) {
122	2.03k	return 0;
123	2.03k	}
124	1.02k	else {
125	1.02k	zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
126	1.02k	return -1;
127	1.02k	}
128	3.05k	}
129
130
131		static zip_int64_t
132	27.3k	pkware_decrypt(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
133	27.3k	struct trad_pkware *ctx;
134	27.3k	zip_int64_t n;
135
136	27.3k	ctx = (struct trad_pkware *)ud;
137
138	27.3k	switch (cmd) {
139	4.27k	case ZIP_SOURCE_OPEN:
140	4.27k	_zip_pkware_keys_reset(&ctx->keys);
141	4.27k	_zip_pkware_decrypt(&ctx->keys, NULL, (const zip_uint8_t *)ctx->password, strlen(ctx->password));
142	4.27k	if (decrypt_header(src, ctx) < 0) {
143	2.24k	return -1;
144	2.24k	}
145	2.03k	return 0;
146
147	4.47k	case ZIP_SOURCE_READ:
148	4.47k	if ((n = zip_source_read(src, data, len)) < 0) {
149	865	zip_error_set_from_source(&ctx->error, src);
150	865	return -1;
151	865	}
152
153	3.60k	_zip_pkware_decrypt(&ctx->keys, (zip_uint8_t )data, (zip_uint8_t )data, (zip_uint64_t)n);
154	3.60k	return n;
155
156	2.03k	case ZIP_SOURCE_CLOSE:
157	2.03k	return 0;
158
159	2.46k	case ZIP_SOURCE_STAT: {
160	2.46k	zip_stat_t *st;
161
162	2.46k	st = (zip_stat_t *)data;
163
164	2.46k	st->encryption_method = ZIP_EM_NONE;
165	2.46k	st->valid \|= ZIP_STAT_ENCRYPTION_METHOD;
166	2.46k	if (st->valid & ZIP_STAT_COMP_SIZE) {
167	2.46k	st->comp_size -= ZIP_CRYPTO_PKWARE_HEADERLEN;
168	2.46k	}
169
170	2.46k	return 0;
171	4.47k	}
172
173	5.48k	case ZIP_SOURCE_SUPPORTS:
174	5.48k	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);
175
176	3.10k	case ZIP_SOURCE_ERROR:
177	3.10k	return zip_error_to_data(&ctx->error, data, len);
178
179	5.48k	case ZIP_SOURCE_FREE:
180	5.48k	trad_pkware_free(ctx);
181	5.48k	return 0;
182
183	0	default:
184	0	return zip_source_pass_to_lower_layer(src, data, len, cmd);
185	27.3k	}
186	27.3k	}
187
188
189		static struct trad_pkware *
190	5.48k	trad_pkware_new(const char password, zip_error_t error) {
191	5.48k	struct trad_pkware *ctx;
192
193	5.48k	if ((ctx = (struct trad_pkware )malloc(sizeof(ctx))) == NULL) {
194	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
195	0	return NULL;
196	0	}
197
198	5.48k	if ((ctx->password = strdup(password)) == NULL) {
199	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
200	0	free(ctx);
201	0	return NULL;
202	0	}
203
204	5.48k	zip_error_init(&ctx->error);
205
206	5.48k	return ctx;
207	5.48k	}
208
209
210		static void
211	5.48k	trad_pkware_free(struct trad_pkware *ctx) {
212	5.48k	if (ctx == NULL) {
213	0	return;
214	0	}
215
216	5.48k	free(ctx->password);
217	5.48k	free(ctx);
218	5.48k	}