zip_source_pkware_decode.c File Reference

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

Go to the source code of this file.

Classes
struct	trad_pkware

Functions
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)

Function Documentation

decrypt_header()

static int decrypt_header ( zip_source_t *  src, struct trad_pkware *  ctx  )

static

Definition at line 81 of file zip_source_pkware_decode.c.

                                                           {
    zip_uint8_t header[ZIP_CRYPTO_PKWARE_HEADERLEN];
    struct zip_stat st;
    zip_int64_t n;
    bool ok = false;
 
    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)) {
        /* stat failed, skip password validation */
        return 0;
    }
 
    /* password verification - two ways:
     *  mtime - InfoZIP way, to avoid computing complete CRC before encrypting data
     *  CRC - old PKWare way
     */
 
    if (st.valid & ZIP_STAT_MTIME) {
        unsigned short dostime, dosdate;
        _zip_u2d_time(st.mtime, &dostime, &dosdate);
        if (header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == dostime >> 8) {
            ok = true;
        }
    }
 
    if (st.valid & ZIP_STAT_CRC) {
        if (header[ZIP_CRYPTO_PKWARE_HEADERLEN - 1] == st.crc >> 24) {
            ok = true;
        }
    }
 
    if (!ok && ((st.valid & (ZIP_STAT_MTIME | ZIP_STAT_CRC)) != 0)) {
        zip_error_set(&ctx->error, ZIP_ER_WRONGPASSWD, 0);
        return -1;
    }
 
    return 0;
}

References _zip_error_set_from_source(), _zip_pkware_decrypt(), _zip_u2d_time(), zip_stat::crc, ctx::error, header, zip_stat::mtime, n, ok, src, zip_stat::valid, ZIP_CRYPTO_PKWARE_HEADERLEN, ZIP_ER_EOF, ZIP_ER_WRONGPASSWD, zip_error_set(), zip_source_read(), zip_source_stat(), ZIP_STAT_CRC, and ZIP_STAT_MTIME.

Referenced by pkware_decrypt().

pkware_decrypt()

static zip_int64_t pkware_decrypt ( zip_source_t *  src, void *  ud, void *  data, zip_uint64_t  len, zip_source_cmd_t  cmd  )

static

Definition at line 133 of file zip_source_pkware_decode.c.

                                                                                                {
    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, -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:
        zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
        return -1;
    }
}

References _zip_error_set_from_source(), _zip_pkware_decrypt(), _zip_pkware_keys_reset(), cmd, zip_stat::comp_size, decrypt_header(), zip_stat::encryption_method, ctx::error, len, n, NULL, src, trad_pkware_free(), zip_stat::valid, ZIP_CRYPTO_PKWARE_HEADERLEN, ZIP_EM_NONE, ZIP_ER_INVAL, zip_error_set(), zip_error_to_data(), ZIP_SOURCE_CLOSE, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, zip_source_make_command_bitmap(), ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, zip_source_read(), ZIP_SOURCE_STAT, ZIP_SOURCE_SUPPORTS, ZIP_STAT_COMP_SIZE, and ZIP_STAT_ENCRYPTION_METHOD.

Referenced by zip_source_pkware_decode().

trad_pkware_free()

static void trad_pkware_free ( struct trad_pkware *  ctx )

static

Definition at line 213 of file zip_source_pkware_decode.c.

                                          {
    if (ctx == NULL) {
        return;
    }
 
    free(ctx->password);
    free(ctx);
}

References free(), and NULL.

Referenced by pkware_decrypt(), and zip_source_pkware_decode().

trad_pkware_new()

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

static

Definition at line 192 of file zip_source_pkware_decode.c.

                                                          {
    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;
}

References ctx::error, error(), free(), malloc(), NULL, trad_pkware::password, strdup(), ZIP_ER_MEMORY, zip_error_init(), and zip_error_set().

Referenced by zip_source_pkware_decode().

zip_source_pkware_decode()

zip_source_t* zip_source_pkware_decode	(	zip_t *	za,
		zip_source_t *	src,
		zip_uint16_t	em,
		int	flags,
		const char *	password
	)

Definition at line 54 of file zip_source_pkware_decode.c.

                                                                                                         {
    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;
}

References zip::error, flags, NULL, trad_pkware::password, pkware_decrypt(), s2, src, trad_pkware_free(), trad_pkware_new(), za, ZIP_CODEC_ENCODE, ZIP_EM_TRAD_PKWARE, ZIP_ER_ENCRNOTSUPP, ZIP_ER_INVAL, zip_error_set(), and zip_source_layered().

Referenced by _zip_get_encryption_implementation().