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/*
* Copyright (c) 2015-2016 Balabit
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation, or (at your option) any later version.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* As an additional exemption you are allowed to compile & link against the
* OpenSSL libraries as published by the OpenSSL project. See the file
* COPYING for details.
*/
#include "linux-audit-parser.h"
#include "scanner/kv-scanner/kv-scanner.h"
#include "utf8utils.h"
#include <string.h>
#include <ctype.h>
const gchar *hexcoded_fields[] =
{
"name",
"proctitle",
"path",
"dir",
"comm",
"ocomm",
"data",
"old",
"new",
NULL
};
static gint
_decode_xdigit(gchar xdigit)
{
if (xdigit >= '0' && xdigit <= '9')
return xdigit - '0';
xdigit = toupper(xdigit);
if (xdigit >= 'A' && xdigit <= 'F')
return xdigit - 'A' + 10;
return -1;
}
static gint
_decode_xbyte(gchar xdigit1, gchar xdigit2)
{
gint nibble_hi, nibble_lo;
nibble_hi = _decode_xdigit(xdigit1);
nibble_lo = _decode_xdigit(xdigit2);
if (nibble_hi < 0 || nibble_lo < 0)
return -1;
return (nibble_hi << 4) + nibble_lo;
}
static gboolean
_is_control_char(gint ch)
{
if (ch < 0x21 || ch > 0x7e)
return TRUE;
return FALSE;
}
static gboolean
_parse_linux_audit_hexstring(GString *decoded_value, const gchar *value, gsize len)
{
gint src;
gboolean kernel_would_have_encoded_this_as_hex = FALSE;
for (src = 0; src < len; src += 2)
{
gint v;
v = _decode_xbyte(value[src], value[src + 1]);
if (v < 0)
return FALSE;
if (_is_control_char(v) || v == '"')
kernel_would_have_encoded_this_as_hex = TRUE;
if (v == 0)
v = '\t';
g_string_append_c(decoded_value, v);
}
if (!kernel_would_have_encoded_this_as_hex)
return FALSE;
return TRUE;
}
static gboolean
_is_field_hex_encoded(const gchar *field)
{
gint i;
if (field[0] == 'a' && isdigit(field[1]))
return TRUE;
for (i = 0; hexcoded_fields[i]; i++)
{
if (strcmp(hexcoded_fields[i], field) == 0)
return TRUE;
}
return FALSE;
}
gboolean
parse_linux_audit_style_hexdump(KVScanner *self)
{
if (!self->value_was_quoted &&
(self->value->len % 2) == 0 &&
isxdigit(self->value->str[0]) &&
_is_field_hex_encoded(self->key->str))
{
if (!_parse_linux_audit_hexstring(self->decoded_value, self->value->str, self->value->len))
return FALSE;
if (!g_utf8_validate(self->decoded_value->str, self->decoded_value->len, NULL))
return FALSE;
return TRUE;
}
return FALSE;
}
static void
_init_scanner(KVParser *self, KVScanner *kv_scanner)
{
kv_parser_init_scanner_method(self, kv_scanner);
kv_scanner_set_transform_value(kv_scanner, parse_linux_audit_style_hexdump);
}
static LogPipe *
_clone(LogPipe *s)
{
KVParser *self = (KVParser *) s;
KVParser *cloned = (KVParser *) linux_audit_parser_new(s->cfg);
return kv_parser_clone_method(cloned, self);
}
LogParser *
linux_audit_parser_new(GlobalConfig *cfg)
{
KVParser *self = g_new0(KVParser, 1);
kv_parser_init_instance(self, cfg);
self->super.super.clone = _clone;
self->init_scanner = _init_scanner;
return &self->super;
}
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