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openssl/crypto/asn1/tasn_enc.c

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/*
* Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stddef.h>
#include <string.h>
#include "internal/cryptlib.h"
#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/objects.h>
#include "crypto/asn1.h"
#include "asn1_local.h"
static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
const ASN1_ITEM *it, int tag, int aclass);
static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
int skcontlen, const ASN1_ITEM *item,
int do_sort, int iclass);
static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
const ASN1_TEMPLATE *tt, int tag, int aclass);
static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
const ASN1_ITEM *it, int flags);
static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
const ASN1_ITEM *it);
/*
* Top level i2d equivalents: the 'ndef' variant instructs the encoder to use
* indefinite length constructed encoding, where appropriate
*/
int ASN1_item_ndef_i2d(ASN1_VALUE *val, unsigned char **out,
const ASN1_ITEM *it)
{
return asn1_item_flags_i2d(val, out, it, ASN1_TFLG_NDEF);
}
int ASN1_item_i2d(ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it)
{
return asn1_item_flags_i2d(val, out, it, 0);
}
/*
* Encode an ASN1 item, this is use by the standard 'i2d' function. 'out'
* points to a buffer to output the data to. The new i2d has one additional
* feature. If the output buffer is NULL (i.e. *out == NULL) then a buffer is
* allocated and populated with the encoding.
*/
static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
const ASN1_ITEM *it, int flags)
{
if (out && !*out) {
unsigned char *p, *buf;
int len;
len = ASN1_item_ex_i2d(&val, NULL, it, -1, flags);
if (len <= 0)
return len;
if ((buf = OPENSSL_malloc(len)) == NULL) {
ASN1err(ASN1_F_ASN1_ITEM_FLAGS_I2D, ERR_R_MALLOC_FAILURE);
return -1;
}
p = buf;
ASN1_item_ex_i2d(&val, &p, it, -1, flags);
*out = buf;
return len;
}
return ASN1_item_ex_i2d(&val, out, it, -1, flags);
}
/*
* Encode an item, taking care of IMPLICIT tagging (if any). This function
* performs the normal item handling: it can be used in external types.
*/
int ASN1_item_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
const ASN1_ITEM *it, int tag, int aclass)
{
const ASN1_TEMPLATE *tt = NULL;
int i, seqcontlen, seqlen, ndef = 1;
const ASN1_EXTERN_FUNCS *ef;
const ASN1_AUX *aux = it->funcs;
ASN1_aux_cb *asn1_cb = 0;
if ((it->itype != ASN1_ITYPE_PRIMITIVE) && !*pval)
return 0;
if (aux && aux->asn1_cb)
asn1_cb = aux->asn1_cb;
switch (it->itype) {
case ASN1_ITYPE_PRIMITIVE:
if (it->templates)
return asn1_template_ex_i2d(pval, out, it->templates,
tag, aclass);
return asn1_i2d_ex_primitive(pval, out, it, tag, aclass);
case ASN1_ITYPE_MSTRING:
/*
* It never makes sense for multi-strings to have implicit tagging, so
* if tag != -1, then this looks like an error in the template.
*/
if (tag != -1) {
ASN1err(ASN1_F_ASN1_ITEM_EX_I2D, ASN1_R_BAD_TEMPLATE);
return -1;
}
return asn1_i2d_ex_primitive(pval, out, it, -1, aclass);
case ASN1_ITYPE_CHOICE:
/*
* It never makes sense for CHOICE types to have implicit tagging, so
* if tag != -1, then this looks like an error in the template.
*/
if (tag != -1) {
ASN1err(ASN1_F_ASN1_ITEM_EX_I2D, ASN1_R_BAD_TEMPLATE);
return -1;
}
if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
return 0;
i = asn1_get_choice_selector(pval, it);
if ((i >= 0) && (i < it->tcount)) {
ASN1_VALUE **pchval;
const ASN1_TEMPLATE *chtt;
chtt = it->templates + i;
pchval = asn1_get_field_ptr(pval, chtt);
return asn1_template_ex_i2d(pchval, out, chtt, -1, aclass);
}
/* Fixme: error condition if selector out of range */
if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
return 0;
break;
case ASN1_ITYPE_EXTERN:
/* If new style i2d it does all the work */
ef = it->funcs;
return ef->asn1_ex_i2d(pval, out, it, tag, aclass);
case ASN1_ITYPE_NDEF_SEQUENCE:
/* Use indefinite length constructed if requested */
if (aclass & ASN1_TFLG_NDEF)
ndef = 2;
/* fall through */
case ASN1_ITYPE_SEQUENCE:
i = asn1_enc_restore(&seqcontlen, out, pval, it);
/* An error occurred */
if (i < 0)
return 0;
/* We have a valid cached encoding... */
if (i > 0)
return seqcontlen;
/* Otherwise carry on */
seqcontlen = 0;
/* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
if (tag == -1) {
tag = V_ASN1_SEQUENCE;
/* Retain any other flags in aclass */
aclass = (aclass & ~ASN1_TFLG_TAG_CLASS)
| V_ASN1_UNIVERSAL;
}
if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
return 0;
/* First work out sequence content length */
for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
const ASN1_TEMPLATE *seqtt;
ASN1_VALUE **pseqval;
int tmplen;
seqtt = asn1_do_adb(pval, tt, 1);
if (!seqtt)
return 0;
pseqval = asn1_get_field_ptr(pval, seqtt);
tmplen = asn1_template_ex_i2d(pseqval, NULL, seqtt, -1, aclass);
if (tmplen == -1 || (tmplen > INT_MAX - seqcontlen))
return -1;
seqcontlen += tmplen;
}
seqlen = ASN1_object_size(ndef, seqcontlen, tag);
if (!out || seqlen == -1)
return seqlen;
/* Output SEQUENCE header */
ASN1_put_object(out, ndef, seqcontlen, tag, aclass);
for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
const ASN1_TEMPLATE *seqtt;
ASN1_VALUE **pseqval;
seqtt = asn1_do_adb(pval, tt, 1);
if (!seqtt)
return 0;
pseqval = asn1_get_field_ptr(pval, seqtt);
/* FIXME: check for errors in enhanced version */
asn1_template_ex_i2d(pseqval, out, seqtt, -1, aclass);
}
if (ndef == 2)
ASN1_put_eoc(out);
if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
return 0;
return seqlen;
default:
return 0;
}
return 0;
}
static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
const ASN1_TEMPLATE *tt, int tag, int iclass)
{
int i, ret, flags, ttag, tclass, ndef;
ASN1_VALUE *tval;
flags = tt->flags;
/*
* If field is embedded then val needs fixing so it is a pointer to
* a pointer to a field.
*/
if (flags & ASN1_TFLG_EMBED) {
tval = (ASN1_VALUE *)pval;
pval = &tval;
}
/*
* Work out tag and class to use: tagging may come either from the
* template or the arguments, not both because this would create
* ambiguity. Additionally the iclass argument may contain some
* additional flags which should be noted and passed down to other
* levels.
*/
if (flags & ASN1_TFLG_TAG_MASK) {
/* Error if argument and template tagging */
if (tag != -1)
/* FIXME: error code here */
return -1;
/* Get tagging from template */
ttag = tt->tag;
tclass = flags & ASN1_TFLG_TAG_CLASS;
} else if (tag != -1) {
/* No template tagging, get from arguments */
ttag = tag;
tclass = iclass & ASN1_TFLG_TAG_CLASS;
} else {
ttag = -1;
tclass = 0;
}
/*
* Remove any class mask from iflag.
*/
iclass &= ~ASN1_TFLG_TAG_CLASS;
/*
* At this point 'ttag' contains the outer tag to use, 'tclass' is the
* class and iclass is any flags passed to this function.
*/
/* if template and arguments require ndef, use it */
if ((flags & ASN1_TFLG_NDEF) && (iclass & ASN1_TFLG_NDEF))
ndef = 2;
else
ndef = 1;
if (flags & ASN1_TFLG_SK_MASK) {
/* SET OF, SEQUENCE OF */
STACK_OF(ASN1_VALUE) *sk = (STACK_OF(ASN1_VALUE) *)*pval;
int isset, sktag, skaclass;
int skcontlen, sklen;
ASN1_VALUE *skitem;
if (!*pval)
return 0;
if (flags & ASN1_TFLG_SET_OF) {
isset = 1;
/* 2 means we reorder */
if (flags & ASN1_TFLG_SEQUENCE_OF)
isset = 2;
} else
isset = 0;
/*
* Work out inner tag value: if EXPLICIT or no tagging use underlying
* type.
*/
if ((ttag != -1) && !(flags & ASN1_TFLG_EXPTAG)) {
sktag = ttag;
skaclass = tclass;
} else {
skaclass = V_ASN1_UNIVERSAL;
if (isset)
sktag = V_ASN1_SET;
else
sktag = V_ASN1_SEQUENCE;
}
/* Determine total length of items */
skcontlen = 0;
for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
int tmplen;
skitem = sk_ASN1_VALUE_value(sk, i);
tmplen = ASN1_item_ex_i2d(&skitem, NULL, ASN1_ITEM_ptr(tt->item),
-1, iclass);
if (tmplen == -1 || (skcontlen > INT_MAX - tmplen))
return -1;
skcontlen += tmplen;
}
sklen = ASN1_object_size(ndef, skcontlen, sktag);
if (sklen == -1)
return -1;
/* If EXPLICIT need length of surrounding tag */
if (flags & ASN1_TFLG_EXPTAG)
ret = ASN1_object_size(ndef, sklen, ttag);
else
ret = sklen;
if (!out || ret == -1)
return ret;
/* Now encode this lot... */
/* EXPLICIT tag */
if (flags & ASN1_TFLG_EXPTAG)
ASN1_put_object(out, ndef, sklen, ttag, tclass);
/* SET or SEQUENCE and IMPLICIT tag */
ASN1_put_object(out, ndef, skcontlen, sktag, skaclass);
/* And the stuff itself */
asn1_set_seq_out(sk, out, skcontlen, ASN1_ITEM_ptr(tt->item),
isset, iclass);
if (ndef == 2) {
ASN1_put_eoc(out);
if (flags & ASN1_TFLG_EXPTAG)
ASN1_put_eoc(out);
}
return ret;
}
if (flags & ASN1_TFLG_EXPTAG) {
/* EXPLICIT tagging */
/* Find length of tagged item */
i = ASN1_item_ex_i2d(pval, NULL, ASN1_ITEM_ptr(tt->item), -1, iclass);
if (!i)
return 0;
/* Find length of EXPLICIT tag */
ret = ASN1_object_size(ndef, i, ttag);
if (out && ret != -1) {
/* Output tag and item */
ASN1_put_object(out, ndef, i, ttag, tclass);
ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item), -1, iclass);
if (ndef == 2)
ASN1_put_eoc(out);
}
return ret;
}
/* Either normal or IMPLICIT tagging: combine class and flags */
return ASN1_item_ex_i2d(pval, out, ASN1_ITEM_ptr(tt->item),
ttag, tclass | iclass);
}
/* Temporary structure used to hold DER encoding of items for SET OF */
typedef struct {
unsigned char *data;
int length;
ASN1_VALUE *field;
} DER_ENC;
static int der_cmp(const void *a, const void *b)
{
const DER_ENC *d1 = a, *d2 = b;
int cmplen, i;
cmplen = (d1->length < d2->length) ? d1->length : d2->length;
i = memcmp(d1->data, d2->data, cmplen);
if (i)
return i;
return d1->length - d2->length;
}
/* Output the content octets of SET OF or SEQUENCE OF */
static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
int skcontlen, const ASN1_ITEM *item,
int do_sort, int iclass)
{
int i;
ASN1_VALUE *skitem;
unsigned char *tmpdat = NULL, *p = NULL;
DER_ENC *derlst = NULL, *tder;
if (do_sort) {
/* Don't need to sort less than 2 items */
if (sk_ASN1_VALUE_num(sk) < 2)
do_sort = 0;
else {
derlst = OPENSSL_malloc(sk_ASN1_VALUE_num(sk)
* sizeof(*derlst));
if (derlst == NULL)
return 0;
tmpdat = OPENSSL_malloc(skcontlen);
if (tmpdat == NULL) {
OPENSSL_free(derlst);
return 0;
}
}
}
/* If not sorting just output each item */
if (!do_sort) {
for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
skitem = sk_ASN1_VALUE_value(sk, i);
ASN1_item_ex_i2d(&skitem, out, item, -1, iclass);
}
return 1;
}
p = tmpdat;
/* Doing sort: build up a list of each member's DER encoding */
for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
skitem = sk_ASN1_VALUE_value(sk, i);
tder->data = p;
tder->length = ASN1_item_ex_i2d(&skitem, &p, item, -1, iclass);
tder->field = skitem;
}
/* Now sort them */
qsort(derlst, sk_ASN1_VALUE_num(sk), sizeof(*derlst), der_cmp);
/* Output sorted DER encoding */
p = *out;
for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
memcpy(p, tder->data, tder->length);
p += tder->length;
}
*out = p;
/* If do_sort is 2 then reorder the STACK */
if (do_sort == 2) {
for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++)
(void)sk_ASN1_VALUE_set(sk, i, tder->field);
}
OPENSSL_free(derlst);
OPENSSL_free(tmpdat);
return 1;
}
static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
const ASN1_ITEM *it, int tag, int aclass)
{
int len;
int utype;
int usetag;
int ndef = 0;
utype = it->utype;
/*
* Get length of content octets and maybe find out the underlying type.
*/
len = asn1_ex_i2c(pval, NULL, &utype, it);
/*
* If SEQUENCE, SET or OTHER then header is included in pseudo content
* octets so don't include tag+length. We need to check here because the
* call to asn1_ex_i2c() could change utype.
*/
if ((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) ||
(utype == V_ASN1_OTHER))
usetag = 0;
else
usetag = 1;
/* -1 means omit type */
if (len == -1)
return 0;
/* -2 return is special meaning use ndef */
if (len == -2) {
ndef = 2;
len = 0;
}
/* If not implicitly tagged get tag from underlying type */
if (tag == -1)
tag = utype;
/* Output tag+length followed by content octets */
if (out) {
if (usetag)
ASN1_put_object(out, ndef, len, tag, aclass);
asn1_ex_i2c(pval, *out, &utype, it);
if (ndef)
ASN1_put_eoc(out);
else
*out += len;
}
if (usetag)
return ASN1_object_size(ndef, len, tag);
return len;
}
/* Produce content octets from a structure */
static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
const ASN1_ITEM *it)
{
ASN1_BOOLEAN *tbool = NULL;
ASN1_STRING *strtmp;
ASN1_OBJECT *otmp;
int utype;
const unsigned char *cont;
unsigned char c;
int len;
const ASN1_PRIMITIVE_FUNCS *pf;
pf = it->funcs;
if (pf && pf->prim_i2c)
return pf->prim_i2c(pval, cout, putype, it);
/* Should type be omitted? */
if ((it->itype != ASN1_ITYPE_PRIMITIVE)
|| (it->utype != V_ASN1_BOOLEAN)) {
if (!*pval)
return -1;
}
if (it->itype == ASN1_ITYPE_MSTRING) {
/* If MSTRING type set the underlying type */
strtmp = (ASN1_STRING *)*pval;
utype = strtmp->type;
*putype = utype;
} else if (it->utype == V_ASN1_ANY) {
/* If ANY set type and pointer to value */
ASN1_TYPE *typ;
typ = (ASN1_TYPE *)*pval;
utype = typ->type;
*putype = utype;
pval = &typ->value.asn1_value;
} else
utype = *putype;
switch (utype) {
case V_ASN1_OBJECT:
otmp = (ASN1_OBJECT *)*pval;
cont = otmp->data;
len = otmp->length;
if (cont == NULL || len == 0)
return -1;
break;
case V_ASN1_NULL:
cont = NULL;
len = 0;
break;
case V_ASN1_BOOLEAN:
tbool = (ASN1_BOOLEAN *)pval;
if (*tbool == -1)
return -1;
if (it->utype != V_ASN1_ANY) {
/*
* Default handling if value == size field then omit
*/
if (*tbool && (it->size > 0))
return -1;
if (!*tbool && !it->size)
return -1;
}
c = (unsigned char)*tbool;
cont = &c;
len = 1;
break;
case V_ASN1_BIT_STRING:
return i2c_ASN1_BIT_STRING((ASN1_BIT_STRING *)*pval,
cout ? &cout : NULL);
case V_ASN1_INTEGER:
case V_ASN1_ENUMERATED:
/*
* These are all have the same content format as ASN1_INTEGER
*/
return i2c_ASN1_INTEGER((ASN1_INTEGER *)*pval, cout ? &cout : NULL);
case V_ASN1_OCTET_STRING:
case V_ASN1_NUMERICSTRING:
case V_ASN1_PRINTABLESTRING:
case V_ASN1_T61STRING:
case V_ASN1_VIDEOTEXSTRING:
case V_ASN1_IA5STRING:
case V_ASN1_UTCTIME:
case V_ASN1_GENERALIZEDTIME:
case V_ASN1_GRAPHICSTRING:
case V_ASN1_VISIBLESTRING:
case V_ASN1_GENERALSTRING:
case V_ASN1_UNIVERSALSTRING:
case V_ASN1_BMPSTRING:
case V_ASN1_UTF8STRING:
case V_ASN1_SEQUENCE:
case V_ASN1_SET:
default:
/* All based on ASN1_STRING and handled the same */
strtmp = (ASN1_STRING *)*pval;
/* Special handling for NDEF */
if ((it->size == ASN1_TFLG_NDEF)
&& (strtmp->flags & ASN1_STRING_FLAG_NDEF)) {
if (cout) {
strtmp->data = cout;
strtmp->length = 0;
}
/* Special return code */
return -2;
}
cont = strtmp->data;
len = strtmp->length;
break;
}
if (cout && len)
memcpy(cout, cont, len);
return len;
}
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