zip_source_winzip_aes_decode.c File Reference

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

Go to the source code of this file.

Classes
struct	winzip_aes

Functions
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)
static bool	verify_hmac (zip_source_t *src, struct winzip_aes *ctx)

Function Documentation

decrypt_header()

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

static

Definition at line 102 of file zip_source_winzip_aes_decode.c.

                                                          {
    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;
}

References _zip_error_set_from_source(), _zip_winzip_aes_free(), _zip_winzip_aes_new(), ctx::error, header, n, NULL, SALT_LENGTH, src, WINZIP_AES_MAX_HEADER_LENGTH, WINZIP_AES_PASSWORD_VERIFY_LENGTH, ZIP_ER_EOF, ZIP_ER_WRONGPASSWD, zip_error_set(), and zip_source_read().

Referenced by winzip_aes_decrypt().

verify_hmac()

static bool verify_hmac ( zip_source_t *  src, struct winzip_aes *  ctx  )

static

Definition at line 133 of file zip_source_winzip_aes_decode.c.

                                                       {
    unsigned char computed[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;
}

References _zip_error_set_from_source(), _zip_winzip_aes_finish(), _zip_winzip_aes_free(), ctx::error, HMAC_LENGTH, NULL, SHA1_LENGTH, src, ZIP_ER_CRC, ZIP_ER_INTERNAL, zip_error_set(), and zip_source_read().

Referenced by winzip_aes_decrypt().

winzip_aes_decrypt()

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

Definition at line 157 of file zip_source_winzip_aes_decode.c.

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

References _zip_error_set_from_source(), _zip_winzip_aes_decrypt(), cmd, zip_stat::comp_size, winzip_aes::data, decrypt_header(), zip_stat::encryption_method, ctx::error, len, n, SALT_LENGTH, src, zip_stat::valid, verify_hmac(), winzip_aes_free(), ZIP_EM_NONE, ZIP_ER_INTERNAL, 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_winzip_aes_decode().

winzip_aes_free()

static void winzip_aes_free ( struct winzip_aes *  ctx )

static

Definition at line 231 of file zip_source_winzip_aes_decode.c.

                                        {
    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);
}

References _zip_crypto_clear, _zip_winzip_aes_free(), ctx::error, free(), NULL, and zip_error_fini().

Referenced by winzip_aes_decrypt(), and zip_source_winzip_aes_decode().

winzip_aes_new()

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

static

Definition at line 245 of file zip_source_winzip_aes_decode.c.

                                                                                         {
    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;
}

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

Referenced by zip_source_winzip_aes_decode().

zip_source_winzip_aes_decode()

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
	)

Definition at line 59 of file zip_source_winzip_aes_decode.c.

                                                                                                                            {
    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;
}

References _zip_error_set_from_source(), zip_stat::comp_size, winzip_aes::encryption_method, zip::error, flags, HMAC_LENGTH, NULL, winzip_aes::password, s2, SALT_LENGTH, src, zip_stat::valid, winzip_aes_decrypt(), winzip_aes_free(), winzip_aes_new(), WINZIP_AES_PASSWORD_VERIFY_LENGTH, za, ZIP_CODEC_ENCODE, ZIP_EM_AES_128, ZIP_EM_AES_192, ZIP_EM_AES_256, ZIP_ER_ENCRNOTSUPP, ZIP_ER_INVAL, ZIP_ER_OPNOTSUPP, zip_error_set(), zip_source_layered(), zip_source_stat(), and ZIP_STAT_COMP_SIZE.

Referenced by _zip_get_encryption_implementation().