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Member "libzip-1.5.2/lib/zip_source_crc.c" (12 Mar 2019, 5837 Bytes) of package /linux/misc/libzip-1.5.2.tar.xz:


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    1 /*
    2   zip_source_crc.c -- pass-through source that calculates CRC32 and size
    3   Copyright (C) 2009-2018 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 <libzip@nih.at>
    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 <limits.h>
   36 #include <stdlib.h>
   37 #include <string.h>
   38 
   39 #include "zipint.h"
   40 
   41 struct crc_context {
   42     int validate;     /* whether to check CRC on EOF and return error on mismatch */
   43     int crc_complete; /* whether CRC was computed for complete file */
   44     zip_error_t error;
   45     zip_uint64_t size;
   46     zip_uint64_t position;     /* current reading position */
   47     zip_uint64_t crc_position; /* how far we've computed the CRC */
   48     zip_uint32_t crc;
   49 };
   50 
   51 static zip_int64_t crc_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
   52 
   53 
   54 zip_source_t *
   55 zip_source_crc(zip_t *za, zip_source_t *src, int validate) {
   56     struct crc_context *ctx;
   57 
   58     if (src == NULL) {
   59     zip_error_set(&za->error, ZIP_ER_INVAL, 0);
   60     return NULL;
   61     }
   62 
   63     if ((ctx = (struct crc_context *)malloc(sizeof(*ctx))) == NULL) {
   64     zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
   65     return NULL;
   66     }
   67 
   68     zip_error_init(&ctx->error);
   69     ctx->validate = validate;
   70     ctx->crc_complete = 0;
   71     ctx->crc_position = 0;
   72     ctx->crc = (zip_uint32_t)crc32(0, NULL, 0);
   73     ctx->size = 0;
   74 
   75     return zip_source_layered(za, src, crc_read, ctx);
   76 }
   77 
   78 
   79 static zip_int64_t
   80 crc_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
   81     struct crc_context *ctx;
   82     zip_int64_t n;
   83 
   84     ctx = (struct crc_context *)_ctx;
   85 
   86     switch (cmd) {
   87     case ZIP_SOURCE_OPEN:
   88     ctx->position = 0;
   89     return 0;
   90 
   91     case ZIP_SOURCE_READ:
   92     if ((n = zip_source_read(src, data, len)) < 0) {
   93         _zip_error_set_from_source(&ctx->error, src);
   94         return -1;
   95     }
   96 
   97     if (n == 0) {
   98         if (ctx->crc_position == ctx->position) {
   99         ctx->crc_complete = 1;
  100         ctx->size = ctx->position;
  101 
  102         if (ctx->validate) {
  103             struct zip_stat st;
  104 
  105             if (zip_source_stat(src, &st) < 0) {
  106             _zip_error_set_from_source(&ctx->error, src);
  107             return -1;
  108             }
  109 
  110             if ((st.valid & ZIP_STAT_CRC) && st.crc != ctx->crc) {
  111             zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
  112             return -1;
  113             }
  114             if ((st.valid & ZIP_STAT_SIZE) && st.size != ctx->size) {
  115             zip_error_set(&ctx->error, ZIP_ER_INCONS, 0);
  116             return -1;
  117             }
  118         }
  119         }
  120     }
  121     else if (!ctx->crc_complete && ctx->position <= ctx->crc_position) {
  122         zip_uint64_t i, nn;
  123 
  124         for (i = ctx->crc_position - ctx->position; i < (zip_uint64_t)n; i += nn) {
  125         nn = ZIP_MIN(UINT_MAX, (zip_uint64_t)n - i);
  126 
  127         ctx->crc = (zip_uint32_t)crc32(ctx->crc, (const Bytef *)data + i, (uInt)nn);
  128         ctx->crc_position += nn;
  129         }
  130     }
  131     ctx->position += (zip_uint64_t)n;
  132     return n;
  133 
  134     case ZIP_SOURCE_CLOSE:
  135     return 0;
  136 
  137     case ZIP_SOURCE_STAT: {
  138     zip_stat_t *st;
  139 
  140     st = (zip_stat_t *)data;
  141 
  142     if (ctx->crc_complete) {
  143         /* TODO: Set comp_size, comp_method, encryption_method?
  144             After all, this only works for uncompressed data. */
  145         st->size = ctx->size;
  146         st->crc = ctx->crc;
  147         st->comp_size = ctx->size;
  148         st->comp_method = ZIP_CM_STORE;
  149         st->encryption_method = ZIP_EM_NONE;
  150         st->valid |= ZIP_STAT_SIZE | ZIP_STAT_CRC | ZIP_STAT_COMP_SIZE | ZIP_STAT_COMP_METHOD | ZIP_STAT_ENCRYPTION_METHOD;
  151     }
  152     return 0;
  153     }
  154 
  155     case ZIP_SOURCE_ERROR:
  156     return zip_error_to_data(&ctx->error, data, len);
  157 
  158     case ZIP_SOURCE_FREE:
  159     free(ctx);
  160     return 0;
  161 
  162     case ZIP_SOURCE_SUPPORTS: {
  163     zip_int64_t mask = zip_source_supports(src);
  164 
  165     if (mask < 0) {
  166         _zip_error_set_from_source(&ctx->error, src);
  167         return -1;
  168     }
  169 
  170     return mask & ~zip_source_make_command_bitmap(ZIP_SOURCE_BEGIN_WRITE, ZIP_SOURCE_COMMIT_WRITE, ZIP_SOURCE_ROLLBACK_WRITE, ZIP_SOURCE_SEEK_WRITE, ZIP_SOURCE_TELL_WRITE, ZIP_SOURCE_REMOVE, ZIP_SOURCE_GET_COMPRESSION_FLAGS, -1);
  171     }
  172 
  173     case ZIP_SOURCE_SEEK: {
  174     zip_int64_t new_position;
  175     zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);
  176 
  177     if (args == NULL) {
  178         return -1;
  179     }
  180     if (zip_source_seek(src, args->offset, args->whence) < 0 || (new_position = zip_source_tell(src)) < 0) {
  181         _zip_error_set_from_source(&ctx->error, src);
  182         return -1;
  183     }
  184 
  185     ctx->position = (zip_uint64_t)new_position;
  186 
  187     return 0;
  188     }
  189 
  190     case ZIP_SOURCE_TELL:
  191     return (zip_int64_t)ctx->position;
  192 
  193     default:
  194     zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
  195     return -1;
  196     }
  197 }