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openssl/crypto/asn1/tasn_dec.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 <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/objects.h>
#include <openssl/buffer.h>
#include <openssl/err.h>
#include "internal/numbers.h"
#include "asn1_local.h"
/*
* Constructed types with a recursive definition (such as can be found in PKCS7)
* could eventually exceed the stack given malicious input with excessive
* recursion. Therefore we limit the stack depth. This is the maximum number of
* recursive invocations of asn1_item_embed_d2i().
*/
#define ASN1_MAX_CONSTRUCTED_NEST 30
static int asn1_item_embed_d2i(ASN1_VALUE **pval, const unsigned char **in,
long len, const ASN1_ITEM *it,
int tag, int aclass, char opt, ASN1_TLC *ctx,
int depth);
static int asn1_check_eoc(const unsigned char **in, long len);
static int asn1_find_end(const unsigned char **in, long len, char inf);
static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
char inf, int tag, int aclass, int depth);
static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen);
static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass,
char *inf, char *cst,
const unsigned char **in, long len,
int exptag, int expclass, char opt, ASN1_TLC *ctx);
static int asn1_template_ex_d2i(ASN1_VALUE **pval,
const unsigned char **in, long len,
const ASN1_TEMPLATE *tt, char opt,
ASN1_TLC *ctx, int depth);
static int asn1_template_noexp_d2i(ASN1_VALUE **val,
const unsigned char **in, long len,
const ASN1_TEMPLATE *tt, char opt,
ASN1_TLC *ctx, int depth);
static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
const unsigned char **in, long len,
const ASN1_ITEM *it,
int tag, int aclass, char opt,
ASN1_TLC *ctx);
static int asn1_ex_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it);
/* Table to convert tags to bit values, used for MSTRING type */
static const unsigned long tag2bit[32] = {
/* tags 0 - 3 */
0, 0, 0, B_ASN1_BIT_STRING,
/* tags 4- 7 */
B_ASN1_OCTET_STRING, 0, 0, B_ASN1_UNKNOWN,
/* tags 8-11 */
B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN,
/* tags 12-15 */
B_ASN1_UTF8STRING, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN, B_ASN1_UNKNOWN,
/* tags 16-19 */
B_ASN1_SEQUENCE, 0, B_ASN1_NUMERICSTRING, B_ASN1_PRINTABLESTRING,
/* tags 20-22 */
B_ASN1_T61STRING, B_ASN1_VIDEOTEXSTRING, B_ASN1_IA5STRING,
/* tags 23-24 */
B_ASN1_UTCTIME, B_ASN1_GENERALIZEDTIME,
/* tags 25-27 */
B_ASN1_GRAPHICSTRING, B_ASN1_ISO64STRING, B_ASN1_GENERALSTRING,
/* tags 28-31 */
B_ASN1_UNIVERSALSTRING, B_ASN1_UNKNOWN, B_ASN1_BMPSTRING, B_ASN1_UNKNOWN,
};
unsigned long ASN1_tag2bit(int tag)
{
if ((tag < 0) || (tag > 30))
return 0;
return tag2bit[tag];
}
/* Macro to initialize and invalidate the cache */
#define asn1_tlc_clear(c) if (c) (c)->valid = 0
/* Version to avoid compiler warning about 'c' always non-NULL */
#define asn1_tlc_clear_nc(c) (c)->valid = 0
/*
* Decode an ASN1 item, this currently behaves just like a standard 'd2i'
* function. 'in' points to a buffer to read the data from, in future we
* will have more advanced versions that can input data a piece at a time and
* this will simply be a special case.
*/
ASN1_VALUE *ASN1_item_d2i(ASN1_VALUE **pval,
const unsigned char **in, long len,
const ASN1_ITEM *it)
{
ASN1_TLC c;
ASN1_VALUE *ptmpval = NULL;
if (!pval)
pval = &ptmpval;
asn1_tlc_clear_nc(&c);
if (ASN1_item_ex_d2i(pval, in, len, it, -1, 0, 0, &c) > 0)
return *pval;
return NULL;
}
int ASN1_item_ex_d2i(ASN1_VALUE **pval, const unsigned char **in, long len,
const ASN1_ITEM *it,
int tag, int aclass, char opt, ASN1_TLC *ctx)
{
int rv;
rv = asn1_item_embed_d2i(pval, in, len, it, tag, aclass, opt, ctx, 0);
if (rv <= 0)
ASN1_item_ex_free(pval, it);
return rv;
}
/*
* Decode an item, taking care of IMPLICIT tagging, if any. If 'opt' set and
* tag mismatch return -1 to handle OPTIONAL
*/
static int asn1_item_embed_d2i(ASN1_VALUE **pval, const unsigned char **in,
long len, const ASN1_ITEM *it,
int tag, int aclass, char opt, ASN1_TLC *ctx,
int depth)
{
const ASN1_TEMPLATE *tt, *errtt = NULL;
const ASN1_EXTERN_FUNCS *ef;
const ASN1_AUX *aux = it->funcs;
ASN1_aux_cb *asn1_cb;
const unsigned char *p = NULL, *q;
unsigned char oclass;
char seq_eoc, seq_nolen, cst, isopt;
long tmplen;
int i;
int otag;
int ret = 0;
ASN1_VALUE **pchptr;
if (!pval)
return 0;
if (aux && aux->asn1_cb)
asn1_cb = aux->asn1_cb;
else
asn1_cb = 0;
if (++depth > ASN1_MAX_CONSTRUCTED_NEST) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_NESTED_TOO_DEEP);
goto err;
}
switch (it->itype) {
case ASN1_ITYPE_PRIMITIVE:
if (it->templates) {
/*
* tagging or OPTIONAL is currently illegal on an item template
* because the flags can't get passed down. In practice this
* isn't a problem: we include the relevant flags from the item
* template in the template itself.
*/
if ((tag != -1) || opt) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I,
ASN1_R_ILLEGAL_OPTIONS_ON_ITEM_TEMPLATE);
goto err;
}
return asn1_template_ex_d2i(pval, in, len,
it->templates, opt, ctx, depth);
}
return asn1_d2i_ex_primitive(pval, in, len, it,
tag, aclass, opt, ctx);
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_EMBED_D2I, ASN1_R_BAD_TEMPLATE);
goto err;
}
p = *in;
/* Just read in tag and class */
ret = asn1_check_tlen(NULL, &otag, &oclass, NULL, NULL,
&p, len, -1, 0, 1, ctx);
if (!ret) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
}
/* Must be UNIVERSAL class */
if (oclass != V_ASN1_UNIVERSAL) {
/* If OPTIONAL, assume this is OK */
if (opt)
return -1;
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_MSTRING_NOT_UNIVERSAL);
goto err;
}
/* Check tag matches bit map */
if (!(ASN1_tag2bit(otag) & it->utype)) {
/* If OPTIONAL, assume this is OK */
if (opt)
return -1;
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_MSTRING_WRONG_TAG);
goto err;
}
return asn1_d2i_ex_primitive(pval, in, len, it, otag, 0, 0, ctx);
case ASN1_ITYPE_EXTERN:
/* Use new style d2i */
ef = it->funcs;
return ef->asn1_ex_d2i(pval, in, len, it, tag, aclass, opt, ctx);
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_EMBED_D2I, ASN1_R_BAD_TEMPLATE);
goto err;
}
if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL))
goto auxerr;
if (*pval) {
/* Free up and zero CHOICE value if initialised */
i = asn1_get_choice_selector(pval, it);
if ((i >= 0) && (i < it->tcount)) {
tt = it->templates + i;
pchptr = asn1_get_field_ptr(pval, tt);
asn1_template_free(pchptr, tt);
asn1_set_choice_selector(pval, -1, it);
}
} else if (!ASN1_item_ex_new(pval, it)) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
}
/* CHOICE type, try each possibility in turn */
p = *in;
for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) {
pchptr = asn1_get_field_ptr(pval, tt);
/*
* We mark field as OPTIONAL so its absence can be recognised.
*/
ret = asn1_template_ex_d2i(pchptr, &p, len, tt, 1, ctx, depth);
/* If field not present, try the next one */
if (ret == -1)
continue;
/* If positive return, read OK, break loop */
if (ret > 0)
break;
/*
* Must be an ASN1 parsing error.
* Free up any partial choice value
*/
asn1_template_free(pchptr, tt);
errtt = tt;
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
}
/* Did we fall off the end without reading anything? */
if (i == it->tcount) {
/* If OPTIONAL, this is OK */
if (opt) {
/* Free and zero it */
ASN1_item_ex_free(pval, it);
return -1;
}
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_NO_MATCHING_CHOICE_TYPE);
goto err;
}
asn1_set_choice_selector(pval, i, it);
if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL))
goto auxerr;
*in = p;
return 1;
case ASN1_ITYPE_NDEF_SEQUENCE:
case ASN1_ITYPE_SEQUENCE:
p = *in;
tmplen = len;
/* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
if (tag == -1) {
tag = V_ASN1_SEQUENCE;
aclass = V_ASN1_UNIVERSAL;
}
/* Get SEQUENCE length and update len, p */
ret = asn1_check_tlen(&len, NULL, NULL, &seq_eoc, &cst,
&p, len, tag, aclass, opt, ctx);
if (!ret) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
} else if (ret == -1)
return -1;
if (aux && (aux->flags & ASN1_AFLG_BROKEN)) {
len = tmplen - (p - *in);
seq_nolen = 1;
}
/* If indefinite we don't do a length check */
else
seq_nolen = seq_eoc;
if (!cst) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_SEQUENCE_NOT_CONSTRUCTED);
goto err;
}
if (!*pval && !ASN1_item_ex_new(pval, it)) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
}
if (asn1_cb && !asn1_cb(ASN1_OP_D2I_PRE, pval, it, NULL))
goto auxerr;
/* Free up and zero any ADB found */
for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) {
if (tt->flags & ASN1_TFLG_ADB_MASK) {
const ASN1_TEMPLATE *seqtt;
ASN1_VALUE **pseqval;
seqtt = asn1_do_adb(pval, tt, 0);
if (seqtt == NULL)
continue;
pseqval = asn1_get_field_ptr(pval, seqtt);
asn1_template_free(pseqval, seqtt);
}
}
/* Get each field entry */
for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) {
const ASN1_TEMPLATE *seqtt;
ASN1_VALUE **pseqval;
seqtt = asn1_do_adb(pval, tt, 1);
if (seqtt == NULL)
goto err;
pseqval = asn1_get_field_ptr(pval, seqtt);
/* Have we ran out of data? */
if (!len)
break;
q = p;
if (asn1_check_eoc(&p, len)) {
if (!seq_eoc) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_UNEXPECTED_EOC);
goto err;
}
len -= p - q;
seq_eoc = 0;
q = p;
break;
}
/*
* This determines the OPTIONAL flag value. The field cannot be
* omitted if it is the last of a SEQUENCE and there is still
* data to be read. This isn't strictly necessary but it
* increases efficiency in some cases.
*/
if (i == (it->tcount - 1))
isopt = 0;
else
isopt = (char)(seqtt->flags & ASN1_TFLG_OPTIONAL);
/*
* attempt to read in field, allowing each to be OPTIONAL
*/
ret = asn1_template_ex_d2i(pseqval, &p, len, seqtt, isopt, ctx,
depth);
if (!ret) {
errtt = seqtt;
goto err;
} else if (ret == -1) {
/*
* OPTIONAL component absent. Free and zero the field.
*/
asn1_template_free(pseqval, seqtt);
continue;
}
/* Update length */
len -= p - q;
}
/* Check for EOC if expecting one */
if (seq_eoc && !asn1_check_eoc(&p, len)) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_MISSING_EOC);
goto err;
}
/* Check all data read */
if (!seq_nolen && len) {
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_SEQUENCE_LENGTH_MISMATCH);
goto err;
}
/*
* If we get here we've got no more data in the SEQUENCE, however we
* may not have read all fields so check all remaining are OPTIONAL
* and clear any that are.
*/
for (; i < it->tcount; tt++, i++) {
const ASN1_TEMPLATE *seqtt;
seqtt = asn1_do_adb(pval, tt, 1);
if (seqtt == NULL)
goto err;
if (seqtt->flags & ASN1_TFLG_OPTIONAL) {
ASN1_VALUE **pseqval;
pseqval = asn1_get_field_ptr(pval, seqtt);
asn1_template_free(pseqval, seqtt);
} else {
errtt = seqtt;
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_FIELD_MISSING);
goto err;
}
}
/* Save encoding */
if (!asn1_enc_save(pval, *in, p - *in, it))
goto auxerr;
if (asn1_cb && !asn1_cb(ASN1_OP_D2I_POST, pval, it, NULL))
goto auxerr;
*in = p;
return 1;
default:
return 0;
}
auxerr:
ASN1err(ASN1_F_ASN1_ITEM_EMBED_D2I, ASN1_R_AUX_ERROR);
err:
if (errtt)
ERR_add_error_data(4, "Field=", errtt->field_name,
", Type=", it->sname);
else
ERR_add_error_data(2, "Type=", it->sname);
return 0;
}
/*
* Templates are handled with two separate functions. One handles any
* EXPLICIT tag and the other handles the rest.
*/
static int asn1_template_ex_d2i(ASN1_VALUE **val,
const unsigned char **in, long inlen,
const ASN1_TEMPLATE *tt, char opt,
ASN1_TLC *ctx, int depth)
{
int flags, aclass;
int ret;
long len;
const unsigned char *p, *q;
char exp_eoc;
if (!val)
return 0;
flags = tt->flags;
aclass = flags & ASN1_TFLG_TAG_CLASS;
p = *in;
/* Check if EXPLICIT tag expected */
if (flags & ASN1_TFLG_EXPTAG) {
char cst;
/*
* Need to work out amount of data available to the inner content and
* where it starts: so read in EXPLICIT header to get the info.
*/
ret = asn1_check_tlen(&len, NULL, NULL, &exp_eoc, &cst,
&p, inlen, tt->tag, aclass, opt, ctx);
q = p;
if (!ret) {
ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
return 0;
} else if (ret == -1)
return -1;
if (!cst) {
ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
ASN1_R_EXPLICIT_TAG_NOT_CONSTRUCTED);
return 0;
}
/* We've found the field so it can't be OPTIONAL now */
ret = asn1_template_noexp_d2i(val, &p, len, tt, 0, ctx, depth);
if (!ret) {
ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I, ERR_R_NESTED_ASN1_ERROR);
return 0;
}
/* We read the field in OK so update length */
len -= p - q;
if (exp_eoc) {
/* If NDEF we must have an EOC here */
if (!asn1_check_eoc(&p, len)) {
ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I, ASN1_R_MISSING_EOC);
goto err;
}
} else {
/*
* Otherwise we must hit the EXPLICIT tag end or its an error
*/
if (len) {
ASN1err(ASN1_F_ASN1_TEMPLATE_EX_D2I,
ASN1_R_EXPLICIT_LENGTH_MISMATCH);
goto err;
}
}
} else
return asn1_template_noexp_d2i(val, in, inlen, tt, opt, ctx, depth);
*in = p;
return 1;
err:
return 0;
}
static int asn1_template_noexp_d2i(ASN1_VALUE **val,
const unsigned char **in, long len,
const ASN1_TEMPLATE *tt, char opt,
ASN1_TLC *ctx, int depth)
{
int flags, aclass;
int ret;
ASN1_VALUE *tval;
const unsigned char *p, *q;
if (!val)
return 0;
flags = tt->flags;
aclass = flags & ASN1_TFLG_TAG_CLASS;
p = *in;
q = p;
/*
* If field is embedded then val needs fixing so it is a pointer to
* a pointer to a field.
*/
if (tt->flags & ASN1_TFLG_EMBED) {
tval = (ASN1_VALUE *)val;
val = &tval;
}
if (flags & ASN1_TFLG_SK_MASK) {
/* SET OF, SEQUENCE OF */
int sktag, skaclass;
char sk_eoc;
/* First work out expected inner tag value */
if (flags & ASN1_TFLG_IMPTAG) {
sktag = tt->tag;
skaclass = aclass;
} else {
skaclass = V_ASN1_UNIVERSAL;
if (flags & ASN1_TFLG_SET_OF)
sktag = V_ASN1_SET;
else
sktag = V_ASN1_SEQUENCE;
}
/* Get the tag */
ret = asn1_check_tlen(&len, NULL, NULL, &sk_eoc, NULL,
&p, len, sktag, skaclass, opt, ctx);
if (!ret) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_NESTED_ASN1_ERROR);
return 0;
} else if (ret == -1)
return -1;
if (!*val)
*val = (ASN1_VALUE *)sk_ASN1_VALUE_new_null();
else {
/*
* We've got a valid STACK: free up any items present
*/
STACK_OF(ASN1_VALUE) *sktmp = (STACK_OF(ASN1_VALUE) *)*val;
ASN1_VALUE *vtmp;
while (sk_ASN1_VALUE_num(sktmp) > 0) {
vtmp = sk_ASN1_VALUE_pop(sktmp);
ASN1_item_ex_free(&vtmp, ASN1_ITEM_ptr(tt->item));
}
}
if (!*val) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_MALLOC_FAILURE);
goto err;
}
/* Read as many items as we can */
while (len > 0) {
ASN1_VALUE *skfield;
q = p;
/* See if EOC found */
if (asn1_check_eoc(&p, len)) {
if (!sk_eoc) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
ASN1_R_UNEXPECTED_EOC);
goto err;
}
len -= p - q;
sk_eoc = 0;
break;
}
skfield = NULL;
if (!asn1_item_embed_d2i(&skfield, &p, len,
ASN1_ITEM_ptr(tt->item), -1, 0, 0, ctx,
depth)) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I,
ERR_R_NESTED_ASN1_ERROR);
/* |skfield| may be partially allocated despite failure. */
ASN1_item_free(skfield, ASN1_ITEM_ptr(tt->item));
goto err;
}
len -= p - q;
if (!sk_ASN1_VALUE_push((STACK_OF(ASN1_VALUE) *)*val, skfield)) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_MALLOC_FAILURE);
ASN1_item_free(skfield, ASN1_ITEM_ptr(tt->item));
goto err;
}
}
if (sk_eoc) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ASN1_R_MISSING_EOC);
goto err;
}
} else if (flags & ASN1_TFLG_IMPTAG) {
/* IMPLICIT tagging */
ret = asn1_item_embed_d2i(val, &p, len,
ASN1_ITEM_ptr(tt->item), tt->tag, aclass, opt,
ctx, depth);
if (!ret) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
} else if (ret == -1)
return -1;
} else {
/* Nothing special */
ret = asn1_item_embed_d2i(val, &p, len, ASN1_ITEM_ptr(tt->item),
-1, 0, opt, ctx, depth);
if (!ret) {
ASN1err(ASN1_F_ASN1_TEMPLATE_NOEXP_D2I, ERR_R_NESTED_ASN1_ERROR);
goto err;
} else if (ret == -1)
return -1;
}
*in = p;
return 1;
err:
return 0;
}
static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
const unsigned char **in, long inlen,
const ASN1_ITEM *it,
int tag, int aclass, char opt, ASN1_TLC *ctx)
{
int ret = 0, utype;
long plen;
char cst, inf, free_cont = 0;
const unsigned char *p;
BUF_MEM buf = { 0, NULL, 0, 0 };
const unsigned char *cont = NULL;
long len;
if (!pval) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_ILLEGAL_NULL);
return 0; /* Should never happen */
}
if (it->itype == ASN1_ITYPE_MSTRING) {
utype = tag;
tag = -1;
} else
utype = it->utype;
if (utype == V_ASN1_ANY) {
/* If type is ANY need to figure out type from tag */
unsigned char oclass;
if (tag >= 0) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_ILLEGAL_TAGGED_ANY);
return 0;
}
if (opt) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
ASN1_R_ILLEGAL_OPTIONAL_ANY);
return 0;
}
p = *in;
ret = asn1_check_tlen(NULL, &utype, &oclass, NULL, NULL,
&p, inlen, -1, 0, 0, ctx);
if (!ret) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR);
return 0;
}
if (oclass != V_ASN1_UNIVERSAL)
utype = V_ASN1_OTHER;
}
if (tag == -1) {
tag = utype;
aclass = V_ASN1_UNIVERSAL;
}
p = *in;
/* Check header */
ret = asn1_check_tlen(&plen, NULL, NULL, &inf, &cst,
&p, inlen, tag, aclass, opt, ctx);
if (!ret) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR);
return 0;
} else if (ret == -1)
return -1;
ret = 0;
/* SEQUENCE, SET and "OTHER" are left in encoded form */
if ((utype == V_ASN1_SEQUENCE)
|| (utype == V_ASN1_SET) || (utype == V_ASN1_OTHER)) {
/*
* Clear context cache for type OTHER because the auto clear when we
* have a exact match won't work
*/
if (utype == V_ASN1_OTHER) {
asn1_tlc_clear(ctx);
}
/* SEQUENCE and SET must be constructed */
else if (!cst) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE,
ASN1_R_TYPE_NOT_CONSTRUCTED);
return 0;
}
cont = *in;
/* If indefinite length constructed find the real end */
if (inf) {
if (!asn1_find_end(&p, plen, inf))
goto err;
len = p - cont;
} else {
len = p - cont + plen;
p += plen;
}
} else if (cst) {
if (utype == V_ASN1_NULL || utype == V_ASN1_BOOLEAN
|| utype == V_ASN1_OBJECT || utype == V_ASN1_INTEGER
|| utype == V_ASN1_ENUMERATED) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ASN1_R_TYPE_NOT_PRIMITIVE);
return 0;
}
/* Free any returned 'buf' content */
free_cont = 1;
/*
* Should really check the internal tags are correct but some things
* may get this wrong. The relevant specs say that constructed string
* types should be OCTET STRINGs internally irrespective of the type.
* So instead just check for UNIVERSAL class and ignore the tag.
*/
if (!asn1_collect(&buf, &p, plen, inf, -1, V_ASN1_UNIVERSAL, 0)) {
goto err;
}
len = buf.length;
/* Append a final null to string */
if (!BUF_MEM_grow_clean(&buf, len + 1)) {
ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_MALLOC_FAILURE);
goto err;
}
buf.data[len] = 0;
cont = (const unsigned char *)buf.data;
} else {
cont = p;
len = plen;
p += plen;
}
/* We now have content length and type: translate into a structure */
/* asn1_ex_c2i may reuse allocated buffer, and so sets free_cont to 0 */
if (!asn1_ex_c2i(pval, cont, len, utype, &free_cont, it))
goto err;
*in = p;
ret = 1;
err:
if (free_cont)
OPENSSL_free(buf.data);
return ret;
}
/* Translate ASN1 content octets into a structure */
static int asn1_ex_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it)
{
ASN1_VALUE **opval = NULL;
ASN1_STRING *stmp;
ASN1_TYPE *typ = NULL;
int ret = 0;
const ASN1_PRIMITIVE_FUNCS *pf;
ASN1_INTEGER **tint;
pf = it->funcs;
if (pf && pf->prim_c2i)
return pf->prim_c2i(pval, cont, len, utype, free_cont, it);
/* If ANY type clear type and set pointer to internal value */
if (it->utype == V_ASN1_ANY) {
if (!*pval) {
typ = ASN1_TYPE_new();
if (typ == NULL)
goto err;
*pval = (ASN1_VALUE *)typ;
} else
typ = (ASN1_TYPE *)*pval;
if (utype != typ->type)
ASN1_TYPE_set(typ, utype, NULL);
opval = pval;
pval = &typ->value.asn1_value;
}
switch (utype) {
case V_ASN1_OBJECT:
if (!c2i_ASN1_OBJECT((ASN1_OBJECT **)pval, &cont, len))
goto err;
break;
case V_ASN1_NULL:
if (len) {
ASN1err(ASN1_F_ASN1_EX_C2I, ASN1_R_NULL_IS_WRONG_LENGTH);
goto err;
}
*pval = (ASN1_VALUE *)1;
break;
case V_ASN1_BOOLEAN:
if (len != 1) {
ASN1err(ASN1_F_ASN1_EX_C2I, ASN1_R_BOOLEAN_IS_WRONG_LENGTH);
goto err;
} else {
ASN1_BOOLEAN *tbool;
tbool = (ASN1_BOOLEAN *)pval;
*tbool = *cont;
}
break;
case V_ASN1_BIT_STRING:
if (!c2i_ASN1_BIT_STRING((ASN1_BIT_STRING **)pval, &cont, len))
goto err;
break;
case V_ASN1_INTEGER:
case V_ASN1_ENUMERATED:
tint = (ASN1_INTEGER **)pval;
if (!c2i_ASN1_INTEGER(tint, &cont, len))
goto err;
/* Fixup type to match the expected form */
(*tint)->type = utype | ((*tint)->type & V_ASN1_NEG);
break;
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_OTHER:
case V_ASN1_SET:
case V_ASN1_SEQUENCE:
default:
if (utype == V_ASN1_BMPSTRING && (len & 1)) {
ASN1err(ASN1_F_ASN1_EX_C2I, ASN1_R_BMPSTRING_IS_WRONG_LENGTH);
goto err;
}
if (utype == V_ASN1_UNIVERSALSTRING && (len & 3)) {
ASN1err(ASN1_F_ASN1_EX_C2I,
ASN1_R_UNIVERSALSTRING_IS_WRONG_LENGTH);
goto err;
}
/* All based on ASN1_STRING and handled the same */
if (!*pval) {
stmp = ASN1_STRING_type_new(utype);
if (stmp == NULL) {
ASN1err(ASN1_F_ASN1_EX_C2I, ERR_R_MALLOC_FAILURE);
goto err;
}
*pval = (ASN1_VALUE *)stmp;
} else {
stmp = (ASN1_STRING *)*pval;
stmp->type = utype;
}
/* If we've already allocated a buffer use it */
if (*free_cont) {
OPENSSL_free(stmp->data);
stmp->data = (unsigned char *)cont; /* UGLY CAST! RL */
stmp->length = len;
*free_cont = 0;
} else {
if (!ASN1_STRING_set(stmp, cont, len)) {
ASN1err(ASN1_F_ASN1_EX_C2I, ERR_R_MALLOC_FAILURE);
ASN1_STRING_free(stmp);
*pval = NULL;
goto err;
}
}
break;
}
/* If ASN1_ANY and NULL type fix up value */
if (typ && (utype == V_ASN1_NULL))
typ->value.ptr = NULL;
ret = 1;
err:
if (!ret) {
ASN1_TYPE_free(typ);
if (opval)
*opval = NULL;
}
return ret;
}
/*
* This function finds the end of an ASN1 structure when passed its maximum
* length, whether it is indefinite length and a pointer to the content. This
* is more efficient than calling asn1_collect because it does not recurse on
* each indefinite length header.
*/
static int asn1_find_end(const unsigned char **in, long len, char inf)
{
uint32_t expected_eoc;
long plen;
const unsigned char *p = *in, *q;
/* If not indefinite length constructed just add length */
if (inf == 0) {
*in += len;
return 1;
}
expected_eoc = 1;
/*
* Indefinite length constructed form. Find the end when enough EOCs are
* found. If more indefinite length constructed headers are encountered
* increment the expected eoc count otherwise just skip to the end of the
* data.
*/
while (len > 0) {
if (asn1_check_eoc(&p, len)) {
expected_eoc--;
if (expected_eoc == 0)
break;
len -= 2;
continue;
}
q = p;
/* Just read in a header: only care about the length */
if (!asn1_check_tlen(&plen, NULL, NULL, &inf, NULL, &p, len,
-1, 0, 0, NULL)) {
ASN1err(ASN1_F_ASN1_FIND_END, ERR_R_NESTED_ASN1_ERROR);
return 0;
}
if (inf) {
if (expected_eoc == UINT32_MAX) {
ASN1err(ASN1_F_ASN1_FIND_END, ERR_R_NESTED_ASN1_ERROR);
return 0;
}
expected_eoc++;
} else {
p += plen;
}
len -= p - q;
}
if (expected_eoc) {
ASN1err(ASN1_F_ASN1_FIND_END, ASN1_R_MISSING_EOC);
return 0;
}
*in = p;
return 1;
}
/*
* This function collects the asn1 data from a constructed string type into
* a buffer. The values of 'in' and 'len' should refer to the contents of the
* constructed type and 'inf' should be set if it is indefinite length.
*/
#ifndef ASN1_MAX_STRING_NEST
/*
* This determines how many levels of recursion are permitted in ASN1 string
* types. If it is not limited stack overflows can occur. If set to zero no
* recursion is allowed at all. Although zero should be adequate examples
* exist that require a value of 1. So 5 should be more than enough.
*/
# define ASN1_MAX_STRING_NEST 5
#endif
static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
char inf, int tag, int aclass, int depth)
{
const unsigned char *p, *q;
long plen;
char cst, ininf;
p = *in;
inf &= 1;
/*
* If no buffer and not indefinite length constructed just pass over the
* encoded data
*/
if (!buf && !inf) {
*in += len;
return 1;
}
while (len > 0) {
q = p;
/* Check for EOC */
if (asn1_check_eoc(&p, len)) {
/*
* EOC is illegal outside indefinite length constructed form
*/
if (!inf) {
ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_UNEXPECTED_EOC);
return 0;
}
inf = 0;
break;
}
if (!asn1_check_tlen(&plen, NULL, NULL, &ininf, &cst, &p,
len, tag, aclass, 0, NULL)) {
ASN1err(ASN1_F_ASN1_COLLECT, ERR_R_NESTED_ASN1_ERROR);
return 0;
}
/* If indefinite length constructed update max length */
if (cst) {
if (depth >= ASN1_MAX_STRING_NEST) {
ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_NESTED_ASN1_STRING);
return 0;
}
if (!asn1_collect(buf, &p, plen, ininf, tag, aclass, depth + 1))
return 0;
} else if (plen && !collect_data(buf, &p, plen))
return 0;
len -= p - q;
}
if (inf) {
ASN1err(ASN1_F_ASN1_COLLECT, ASN1_R_MISSING_EOC);
return 0;
}
*in = p;
return 1;
}
static int collect_data(BUF_MEM *buf, const unsigned char **p, long plen)
{
int len;
if (buf) {
len = buf->length;
if (!BUF_MEM_grow_clean(buf, len + plen)) {
ASN1err(ASN1_F_COLLECT_DATA, ERR_R_MALLOC_FAILURE);
return 0;
}
memcpy(buf->data + len, *p, plen);
}
*p += plen;
return 1;
}
/* Check for ASN1 EOC and swallow it if found */
static int asn1_check_eoc(const unsigned char **in, long len)
{
const unsigned char *p;
if (len < 2)
return 0;
p = *in;
if (!p[0] && !p[1]) {
*in += 2;
return 1;
}
return 0;
}
/*
* Check an ASN1 tag and length: a bit like ASN1_get_object but it sets the
* length for indefinite length constructed form, we don't know the exact
* length but we can set an upper bound to the amount of data available minus
* the header length just read.
*/
static int asn1_check_tlen(long *olen, int *otag, unsigned char *oclass,
char *inf, char *cst,
const unsigned char **in, long len,
int exptag, int expclass, char opt, ASN1_TLC *ctx)
{
int i;
int ptag, pclass;
long plen;
const unsigned char *p, *q;
p = *in;
q = p;
if (ctx && ctx->valid) {
i = ctx->ret;
plen = ctx->plen;
pclass = ctx->pclass;
ptag = ctx->ptag;
p += ctx->hdrlen;
} else {
i = ASN1_get_object(&p, &plen, &ptag, &pclass, len);
if (ctx) {
ctx->ret = i;
ctx->plen = plen;
ctx->pclass = pclass;
ctx->ptag = ptag;
ctx->hdrlen = p - q;
ctx->valid = 1;
/*
* If definite length, and no error, length + header can't exceed
* total amount of data available.
*/
if (!(i & 0x81) && ((plen + ctx->hdrlen) > len)) {
ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_TOO_LONG);
asn1_tlc_clear(ctx);
return 0;
}
}
}
if (i & 0x80) {
ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_BAD_OBJECT_HEADER);
asn1_tlc_clear(ctx);
return 0;
}
if (exptag >= 0) {
if ((exptag != ptag) || (expclass != pclass)) {
/*
* If type is OPTIONAL, not an error: indicate missing type.
*/
if (opt)
return -1;
asn1_tlc_clear(ctx);
ASN1err(ASN1_F_ASN1_CHECK_TLEN, ASN1_R_WRONG_TAG);
return 0;
}
/*
* We have a tag and class match: assume we are going to do something
* with it
*/
asn1_tlc_clear(ctx);
}
if (i & 1)
plen = len - (p - q);
if (inf)
*inf = i & 1;
if (cst)
*cst = i & V_ASN1_CONSTRUCTED;
if (olen)
*olen = plen;
if (oclass)
*oclass = pclass;
if (otag)
*otag = ptag;
*in = p;
return 1;
}
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