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/*
Fuzz sddl decoding and encoding
Copyright (C) Catalyst IT 2023
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; either version 3 of the License, 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, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "libcli/security/security.h"
#include "librpc/gen_ndr/conditional_ace.h"
#include "fuzzing/fuzzing.h"
#include "util/charset/charset.h"
#define MAX_LENGTH (100 * 1024 - 1)
static char sddl_string[MAX_LENGTH + 1] = {0};
static struct dom_sid dom_sid = {0};
int LLVMFuzzerInitialize(int *argc, char ***argv)
{
string_to_sid(&dom_sid,
"S-1-5-21-2470180966-3899876309-2637894779");
return 0;
}
int LLVMFuzzerTestOneInput(const uint8_t *input, size_t len)
{
TALLOC_CTX *mem_ctx = NULL;
struct security_descriptor *sd1 = NULL;
struct security_descriptor *sd2 = NULL;
char *result = NULL;
bool ok;
if (len > MAX_LENGTH) {
return 0;
}
memcpy(sddl_string, input, len);
sddl_string[len] = '\0';
mem_ctx = talloc_new(NULL);
sd1 = sddl_decode(mem_ctx, sddl_string, &dom_sid);
if (sd1 == NULL) {
goto end;
}
result = sddl_encode(mem_ctx, sd1, &dom_sid);
if (result == NULL) {
/*
* Because Samba currently doesn't enforce strict
* utf-8 parsing, illegal utf-8 sequences in
* sddl_string could have ferried bad characters
* through into the security descriptor conditions
* that we then find we can't encode.
*
* The proper solution is strict UTF-8 enforcement in
* sddl_decode, but for now we forgive unencodable
* security descriptors made from bad utf-8.
*/
size_t byte_len, char_len, utf16_len;
ok = utf8_check(sddl_string, len,
&byte_len, &char_len, &utf16_len);
if (!ok) {
goto end;
}
/* utf-8 was fine, but we couldn't encode! */
abort();
}
sd2 = sddl_decode(mem_ctx, result, &dom_sid);
if (sd2 == NULL) {
if (strlen(result) > CONDITIONAL_ACE_MAX_LENGTH) {
/*
* This could fail if a unicode string or
* attribute name that contains escapable
* bytes (e.g '\x0b') in an unescaped form in
* the original string ends up with them in
* the escaped form ("%000b") in the result
* string, making the entire attribute name
* too long for the arbitrary limit we set for
* SDDL attribute names.
*
* We could increase that arbitrary limit (to,
* say, CONDITIONAL_ACE_MAX_LENGTH * 5), but
* that is getting very far from real world
* needs.
*/
goto end;
}
abort();
}
ok = security_descriptor_equal(sd1, sd2);
if (!ok) {
abort();
}
end:
talloc_free(mem_ctx);
return 0;
}
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