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/******************************************************
Copyright (c) 2011 Percona Ireland Ltd.
The xbcrypt format reader implementation.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*******************************************************/
#include "xbcrypt.h"
struct xb_rcrypt_struct {
void *userdata;
xb_crypt_read_callback *read;
void *buffer;
size_t bufsize;
ulonglong offset;
};
xb_rcrypt_t *
xb_crypt_read_open(void *userdata, xb_crypt_read_callback *onread)
{
xb_rcrypt_t *crypt;
xb_ad(onread);
crypt = (xb_rcrypt_t *) my_malloc(sizeof(xb_rcrypt_t), MYF(MY_FAE));
crypt->userdata = userdata;
crypt->read = onread;
crypt->buffer = NULL;
crypt->bufsize = 0;
crypt->offset = 0;
return crypt;
}
xb_rcrypt_result_t
xb_crypt_read_chunk(xb_rcrypt_t *crypt, void **buf, size_t *olen, size_t *elen)
{
uchar tmpbuf[XB_CRYPT_CHUNK_MAGIC_SIZE + 8 + 8 + 8 + 4];
uchar *ptr;
ulonglong tmp;
ulong checksum, checksum_exp;
ssize_t bytesread;
xb_rcrypt_result_t result = XB_CRYPT_READ_CHUNK;
if ((bytesread = crypt->read(crypt->userdata, tmpbuf, sizeof(tmpbuf)))
!= sizeof(tmpbuf)) {
if (bytesread == 0) {
result = XB_CRYPT_READ_EOF;
goto err;
} else {
msg("%s:%s: unable to read chunk header data at "
"offset 0x%llx.\n",
my_progname, __FUNCTION__, crypt->offset);
result = XB_CRYPT_READ_ERROR;
goto err;
}
}
ptr = tmpbuf;
if (memcmp(ptr, XB_CRYPT_CHUNK_MAGIC, XB_CRYPT_CHUNK_MAGIC_SIZE)
!= 0) {
msg("%s:%s: wrong chunk magic at offset 0x%llx.\n",
my_progname, __FUNCTION__, crypt->offset);
result = XB_CRYPT_READ_ERROR;
goto err;
}
ptr += XB_CRYPT_CHUNK_MAGIC_SIZE;
crypt->offset += XB_CRYPT_CHUNK_MAGIC_SIZE;
tmp = uint8korr(ptr); /* reserved */
ptr += 8;
crypt->offset += 8;
tmp = uint8korr(ptr); /* original size */
ptr += 8;
if (tmp > INT_MAX) {
msg("%s:%s: invalid original size at offset 0x%llx.\n",
my_progname, __FUNCTION__, crypt->offset);
result = XB_CRYPT_READ_ERROR;
goto err;
}
crypt->offset += 8;
*olen = (size_t)tmp;
tmp = uint8korr(ptr); /* encrypted size */
ptr += 8;
if (tmp > INT_MAX) {
msg("%s:%s: invalid encrypted size at offset 0x%llx.\n",
my_progname, __FUNCTION__, crypt->offset);
result = XB_CRYPT_READ_ERROR;
goto err;
}
crypt->offset += 8;
*elen = (size_t)tmp;
checksum_exp = uint4korr(ptr); /* checksum */
ptr += 4;
crypt->offset += 4;
if (*olen > crypt->bufsize) {
if (crypt->buffer) {
crypt->buffer = my_realloc(crypt->buffer, *olen,
MYF(MY_WME));
if (crypt->buffer == NULL) {
msg("%s:%s: failed to increase buffer to "
"%llu bytes.\n", my_progname, __FUNCTION__,
(ulonglong)*olen);
result = XB_CRYPT_READ_ERROR;
goto err;
}
} else {
crypt->buffer = my_malloc(*olen, MYF(MY_WME));
if (crypt->buffer == NULL) {
msg("%s:%s: failed to allocate buffer of "
"%llu bytes.\n", my_progname, __FUNCTION__,
(ulonglong)*olen);
result = XB_CRYPT_READ_ERROR;
goto err;
}
}
crypt->bufsize = *olen;
}
if (*elen > 0) {
if (crypt->read(crypt->userdata, crypt->buffer, *elen)
!= (ssize_t)*elen) {
msg("%s:%s: failed to read %lld bytes for chunk payload "
"at offset 0x%llx.\n", my_progname, __FUNCTION__,
(ulonglong)*elen, crypt->offset);
result = XB_CRYPT_READ_ERROR;
goto err;
}
}
checksum = crc32(0, crypt->buffer, *elen);
if (checksum != checksum_exp) {
msg("%s:%s invalid checksum at offset 0x%llx, "
"expected 0x%lx, actual 0x%lx.\n", my_progname, __FUNCTION__,
crypt->offset, checksum_exp, checksum);
result = XB_CRYPT_READ_ERROR;
goto err;
}
crypt->offset += *elen;
*buf = crypt->buffer;
goto exit;
err:
*buf = NULL;
*olen = 0;
*elen = 0;
exit:
return result;
}
int xb_crypt_read_close(xb_rcrypt_t *crypt)
{
if (crypt->buffer)
MY_FREE(crypt->buffer);
MY_FREE(crypt);
return 0;
}
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