9c9dac2b16
Heimdal's ASN.1 compiler generates code that allows specially crafted DER encodings of CHOICEs to invoke the wrong free function on the decoded structure upon decode error. This is known to impact the Heimdal KDC, leading to an invalid free() of an address partly or wholly under the control of the attacker, in turn leading to a potential remote code execution (RCE) vulnerability. This error affects the DER codec for all CHOICE types used in Heimdal, though not all cases will be exploitable. We have not completed a thorough analysis of all the Heimdal components affected, thus the Kerberos client, the X.509 library, and other parts, may be affected as well. This bug has been in Heimdal since 2005. It was first reported by Douglas Bagnall, though it had been found independently by the Heimdal maintainers via fuzzing a few weeks earlier.
241 lines
7.4 KiB
C
241 lines
7.4 KiB
C
/*
|
|
* Copyright (c) 1997 - 2005 Kungliga Tekniska Högskolan
|
|
* (Royal Institute of Technology, Stockholm, Sweden).
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
*
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* 3. Neither the name of the Institute nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "gen_locl.h"
|
|
|
|
RCSID("$Id$");
|
|
|
|
static void
|
|
free_primitive (const char *typename, const char *name)
|
|
{
|
|
fprintf (codefile, "der_free_%s(%s);\n", typename, name);
|
|
}
|
|
|
|
static void
|
|
free_type (const char *name, const Type *t, int preserve)
|
|
{
|
|
switch (t->type) {
|
|
case TType:
|
|
#if 0
|
|
free_type (name, t->symbol->type, preserve);
|
|
#endif
|
|
fprintf (codefile, "free_%s(%s);\n", t->symbol->gen_name, name);
|
|
break;
|
|
case TInteger:
|
|
if (t->range == NULL && t->members == NULL) {
|
|
free_primitive ("heim_integer", name);
|
|
break;
|
|
}
|
|
/* HEIM_FALLTHROUGH; */
|
|
case TBoolean:
|
|
case TEnumerated :
|
|
case TNull:
|
|
case TGeneralizedTime:
|
|
case TUTCTime:
|
|
/*
|
|
* This doesn't do much, but it leaves zeros where garbage might
|
|
* otherwise have been found. Gets us closer to having the equivalent
|
|
* of a memset()-to-zero data structure after calling the free
|
|
* functions.
|
|
*/
|
|
fprintf(codefile, "*%s = 0;\n", name);
|
|
break;
|
|
case TBitString:
|
|
if (HEIM_TAILQ_EMPTY(t->members))
|
|
free_primitive("bit_string", name);
|
|
break;
|
|
case TOctetString:
|
|
free_primitive ("octet_string", name);
|
|
break;
|
|
case TChoice:
|
|
case TSet:
|
|
case TSequence: {
|
|
Member *m, *have_ellipsis = NULL;
|
|
|
|
if (t->members == NULL)
|
|
break;
|
|
|
|
if ((t->type == TSequence || t->type == TChoice) && preserve)
|
|
fprintf(codefile, "der_free_octet_string(&data->_save);\n");
|
|
|
|
if(t->type == TChoice)
|
|
fprintf(codefile, "switch((%s)->element) {\n", name);
|
|
|
|
HEIM_TAILQ_FOREACH(m, t->members, members) {
|
|
char *s;
|
|
|
|
if (m->ellipsis){
|
|
have_ellipsis = m;
|
|
continue;
|
|
}
|
|
|
|
if(t->type == TChoice)
|
|
fprintf(codefile, "case %s:\n", m->label);
|
|
if (asprintf (&s, "%s(%s)->%s%s",
|
|
m->optional ? "" : "&", name,
|
|
t->type == TChoice ? "u." : "", m->gen_name) < 0 || s == NULL)
|
|
errx(1, "malloc");
|
|
if(m->optional)
|
|
fprintf(codefile, "if(%s) {\n", s);
|
|
free_type (s, m->type, FALSE);
|
|
if(m->optional)
|
|
fprintf(codefile,
|
|
"free(%s);\n"
|
|
"%s = NULL;\n"
|
|
"}\n",s, s);
|
|
free (s);
|
|
if(t->type == TChoice)
|
|
fprintf(codefile, "break;\n");
|
|
}
|
|
|
|
if(t->type == TChoice) {
|
|
if (have_ellipsis)
|
|
fprintf(codefile,
|
|
"case %s:\n"
|
|
"der_free_octet_string(&(%s)->u.%s);\n"
|
|
"break;",
|
|
have_ellipsis->label,
|
|
name, have_ellipsis->gen_name);
|
|
fprintf(codefile, "}\n");
|
|
}
|
|
break;
|
|
}
|
|
case TSetOf:
|
|
case TSequenceOf: {
|
|
char *n;
|
|
|
|
fprintf (codefile, "if ((%s)->val)\nwhile((%s)->len){\n", name, name);
|
|
if (asprintf (&n, "&(%s)->val[(%s)->len-1]", name, name) < 0 || n == NULL)
|
|
errx(1, "malloc");
|
|
free_type(n, t->subtype, FALSE);
|
|
fprintf(codefile,
|
|
"(%s)->len--;\n"
|
|
"} else (%s)->len = 0;\n",
|
|
name, name);
|
|
fprintf(codefile,
|
|
"free((%s)->val);\n"
|
|
"(%s)->val = NULL;\n", name, name);
|
|
free(n);
|
|
break;
|
|
}
|
|
case TGeneralString:
|
|
free_primitive ("general_string", name);
|
|
break;
|
|
case TTeletexString:
|
|
free_primitive ("general_string", name);
|
|
break;
|
|
case TUTF8String:
|
|
free_primitive ("utf8string", name);
|
|
break;
|
|
case TPrintableString:
|
|
free_primitive ("printable_string", name);
|
|
break;
|
|
case TIA5String:
|
|
free_primitive ("ia5_string", name);
|
|
break;
|
|
case TBMPString:
|
|
free_primitive ("bmp_string", name);
|
|
break;
|
|
case TUniversalString:
|
|
free_primitive ("universal_string", name);
|
|
break;
|
|
case TVisibleString:
|
|
free_primitive ("visible_string", name);
|
|
break;
|
|
case TTag:
|
|
free_type (name, t->subtype, preserve);
|
|
break;
|
|
case TOID :
|
|
free_primitive ("oid", name);
|
|
break;
|
|
default :
|
|
abort ();
|
|
}
|
|
}
|
|
|
|
void
|
|
generate_type_free (const Symbol *s)
|
|
{
|
|
struct decoration deco;
|
|
ssize_t more_deco = -1;
|
|
int preserve = preserve_type(s->name) ? TRUE : FALSE;
|
|
|
|
fprintf (codefile, "void ASN1CALL\n"
|
|
"free_%s(%s *data)\n"
|
|
"{\n",
|
|
s->gen_name, s->gen_name);
|
|
|
|
free_type ("data", s->type, preserve);
|
|
while (decorate_type(s->gen_name, &deco, &more_deco)) {
|
|
if (deco.ext && deco.free_function_name == NULL) {
|
|
/* Decorated with field of external type but no free function */
|
|
if (deco.ptr)
|
|
fprintf(codefile, "(data)->%s = 0;\n", deco.field_name);
|
|
else
|
|
fprintf(codefile,
|
|
"memset(&(data)->%s, 0, sizeof((data)->%s));\n",
|
|
deco.field_name, deco.field_name);
|
|
} else if (deco.ext) {
|
|
/* Decorated with field of external type w/ free function */
|
|
if (deco.ptr) {
|
|
fprintf(codefile, "if ((data)->%s) {\n", deco.field_name);
|
|
fprintf(codefile, "%s((data)->%s);\n",
|
|
deco.free_function_name, deco.field_name);
|
|
fprintf(codefile, "(data)->%s = 0;\n", deco.field_name);
|
|
fprintf(codefile, "}\n");
|
|
} else {
|
|
fprintf(codefile, "%s(&(data)->%s);\n",
|
|
deco.free_function_name, deco.field_name);
|
|
fprintf(codefile,
|
|
"memset(&(data)->%s, 0, sizeof((data)->%s));\n",
|
|
deco.field_name, deco.field_name);
|
|
}
|
|
} else if (deco.opt) {
|
|
/* Decorated with optional field of ASN.1 type */
|
|
fprintf(codefile, "if ((data)->%s) {\n", deco.field_name);
|
|
fprintf(codefile, "free_%s((data)->%s);\n",
|
|
deco.field_type, deco.field_name);
|
|
fprintf(codefile, "free((data)->%s);\n", deco.field_name);
|
|
fprintf(codefile, "(data)->%s = NULL;\n", deco.field_name);
|
|
fprintf(codefile, "}\n");
|
|
} else {
|
|
/* Decorated with required field of ASN.1 type */
|
|
fprintf(codefile, "free_%s(&(data)->%s);\n",
|
|
deco.field_type, deco.field_name);
|
|
}
|
|
free(deco.field_type);
|
|
}
|
|
fprintf (codefile, "}\n\n");
|
|
}
|
|
|