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samba-mirror/lib/util/asn1.c
Jeremy Allison b9d3fd4cc5 lib: util: Check *every* asn1 return call and early return.
Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Volker Lendecke <Volker.Lendecke@SerNet.DE>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Fri Sep 19 01:29:00 CEST 2014 on sn-devel-104
2014-09-19 01:29:00 +02:00

1048 lines
24 KiB
C

/*
Unix SMB/CIFS implementation.
simple ASN1 routines
Copyright (C) Andrew Tridgell 2001
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 "../lib/util/asn1.h"
/* allocate an asn1 structure */
struct asn1_data *asn1_init(TALLOC_CTX *mem_ctx)
{
struct asn1_data *ret = talloc_zero(mem_ctx, struct asn1_data);
if (ret == NULL) {
DEBUG(0,("asn1_init failed! out of memory\n"));
}
return ret;
}
/* free an asn1 structure */
void asn1_free(struct asn1_data *data)
{
talloc_free(data);
}
/* write to the ASN1 buffer, advancing the buffer pointer */
bool asn1_write(struct asn1_data *data, const void *p, int len)
{
if (data->has_error) return false;
if (data->length < data->ofs+len) {
uint8_t *newp;
newp = talloc_realloc(data, data->data, uint8_t, data->ofs+len);
if (!newp) {
data->has_error = true;
return false;
}
data->data = newp;
data->length = data->ofs+len;
}
memcpy(data->data + data->ofs, p, len);
data->ofs += len;
return true;
}
/* useful fn for writing a uint8_t */
bool asn1_write_uint8(struct asn1_data *data, uint8_t v)
{
return asn1_write(data, &v, 1);
}
/* push a tag onto the asn1 data buffer. Used for nested structures */
bool asn1_push_tag(struct asn1_data *data, uint8_t tag)
{
struct nesting *nesting;
asn1_write_uint8(data, tag);
nesting = talloc(data, struct nesting);
if (!nesting) {
data->has_error = true;
return false;
}
nesting->start = data->ofs;
nesting->next = data->nesting;
data->nesting = nesting;
return asn1_write_uint8(data, 0xff);
}
/* pop a tag */
bool asn1_pop_tag(struct asn1_data *data)
{
struct nesting *nesting;
size_t len;
nesting = data->nesting;
if (!nesting) {
data->has_error = true;
return false;
}
len = data->ofs - (nesting->start+1);
/* yes, this is ugly. We don't know in advance how many bytes the length
of a tag will take, so we assumed 1 byte. If we were wrong then we
need to correct our mistake */
if (len > 0xFFFFFF) {
data->data[nesting->start] = 0x84;
if (!asn1_write_uint8(data, 0)) return false;
if (!asn1_write_uint8(data, 0)) return false;
if (!asn1_write_uint8(data, 0)) return false;
if (!asn1_write_uint8(data, 0)) return false;
memmove(data->data+nesting->start+5, data->data+nesting->start+1, len);
data->data[nesting->start+1] = (len>>24) & 0xFF;
data->data[nesting->start+2] = (len>>16) & 0xFF;
data->data[nesting->start+3] = (len>>8) & 0xFF;
data->data[nesting->start+4] = len&0xff;
} else if (len > 0xFFFF) {
data->data[nesting->start] = 0x83;
if (!asn1_write_uint8(data, 0)) return false;
if (!asn1_write_uint8(data, 0)) return false;
if (!asn1_write_uint8(data, 0)) return false;
memmove(data->data+nesting->start+4, data->data+nesting->start+1, len);
data->data[nesting->start+1] = (len>>16) & 0xFF;
data->data[nesting->start+2] = (len>>8) & 0xFF;
data->data[nesting->start+3] = len&0xff;
} else if (len > 255) {
data->data[nesting->start] = 0x82;
if (!asn1_write_uint8(data, 0)) return false;
if (!asn1_write_uint8(data, 0)) return false;
memmove(data->data+nesting->start+3, data->data+nesting->start+1, len);
data->data[nesting->start+1] = len>>8;
data->data[nesting->start+2] = len&0xff;
} else if (len > 127) {
data->data[nesting->start] = 0x81;
if (!asn1_write_uint8(data, 0)) return false;
memmove(data->data+nesting->start+2, data->data+nesting->start+1, len);
data->data[nesting->start+1] = len;
} else {
data->data[nesting->start] = len;
}
data->nesting = nesting->next;
talloc_free(nesting);
return true;
}
/* "i" is the one's complement representation, as is the normal result of an
* implicit signed->unsigned conversion */
static bool push_int_bigendian(struct asn1_data *data, unsigned int i, bool negative)
{
uint8_t lowest = i & 0xFF;
i = i >> 8;
if (i != 0)
if (!push_int_bigendian(data, i, negative))
return false;
if (data->nesting->start+1 == data->ofs) {
/* We did not write anything yet, looking at the highest
* valued byte */
if (negative) {
/* Don't write leading 0xff's */
if (lowest == 0xFF)
return true;
if ((lowest & 0x80) == 0) {
/* The only exception for a leading 0xff is if
* the highest bit is 0, which would indicate
* a positive value */
if (!asn1_write_uint8(data, 0xff))
return false;
}
} else {
if (lowest & 0x80) {
/* The highest bit of a positive integer is 1,
* this would indicate a negative number. Push
* a 0 to indicate a positive one */
if (!asn1_write_uint8(data, 0))
return false;
}
}
}
return asn1_write_uint8(data, lowest);
}
/* write an Integer without the tag framing. Needed for example for the LDAP
* Abandon Operation */
bool asn1_write_implicit_Integer(struct asn1_data *data, int i)
{
if (i == -1) {
/* -1 is special as it consists of all-0xff bytes. In
push_int_bigendian this is the only case that is not
properly handled, as all 0xff bytes would be handled as
leading ones to be ignored. */
return asn1_write_uint8(data, 0xff);
} else {
return push_int_bigendian(data, i, i<0);
}
}
/* write an integer */
bool asn1_write_Integer(struct asn1_data *data, int i)
{
if (!asn1_push_tag(data, ASN1_INTEGER)) return false;
if (!asn1_write_implicit_Integer(data, i)) return false;
return asn1_pop_tag(data);
}
/* write a BIT STRING */
bool asn1_write_BitString(struct asn1_data *data, const void *p, size_t length, uint8_t padding)
{
if (!asn1_push_tag(data, ASN1_BIT_STRING)) return false;
if (!asn1_write_uint8(data, padding)) return false;
if (!asn1_write(data, p, length)) return false;
return asn1_pop_tag(data);
}
bool ber_write_OID_String(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, const char *OID)
{
unsigned int v, v2;
const char *p = (const char *)OID;
char *newp;
int i;
if (!isdigit(*p)) return false;
v = strtoul(p, &newp, 10);
if (newp[0] != '.') return false;
p = newp + 1;
if (!isdigit(*p)) return false;
v2 = strtoul(p, &newp, 10);
if (newp[0] != '.') return false;
p = newp + 1;
/*the ber representation can't use more space then the string one */
*blob = data_blob_talloc(mem_ctx, NULL, strlen(OID));
if (!blob->data) return false;
blob->data[0] = 40*v + v2;
i = 1;
while (*p) {
if (!isdigit(*p)) return false;
v = strtoul(p, &newp, 10);
if (newp[0] == '.') {
p = newp + 1;
/* check for empty last component */
if (!*p) return false;
} else if (newp[0] == '\0') {
p = newp;
} else {
data_blob_free(blob);
return false;
}
if (v >= (1<<28)) blob->data[i++] = (0x80 | ((v>>28)&0x7f));
if (v >= (1<<21)) blob->data[i++] = (0x80 | ((v>>21)&0x7f));
if (v >= (1<<14)) blob->data[i++] = (0x80 | ((v>>14)&0x7f));
if (v >= (1<<7)) blob->data[i++] = (0x80 | ((v>>7)&0x7f));
blob->data[i++] = (v&0x7f);
}
blob->length = i;
return true;
}
/**
* Serialize partial OID string.
* Partial OIDs are in the form:
* 1:2.5.6:0x81
* 1:2.5.6:0x8182
*/
bool ber_write_partial_OID_String(TALLOC_CTX *mem_ctx, DATA_BLOB *blob, const char *partial_oid)
{
TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
char *oid = talloc_strdup(tmp_ctx, partial_oid);
char *p;
/* truncate partial part so ber_write_OID_String() works */
p = strchr(oid, ':');
if (p) {
*p = '\0';
p++;
}
if (!ber_write_OID_String(mem_ctx, blob, oid)) {
talloc_free(tmp_ctx);
return false;
}
/* Add partially encoded sub-identifier */
if (p) {
DATA_BLOB tmp_blob = strhex_to_data_blob(tmp_ctx, p);
if (!data_blob_append(mem_ctx, blob, tmp_blob.data,
tmp_blob.length)) {
talloc_free(tmp_ctx);
return false;
}
}
talloc_free(tmp_ctx);
return true;
}
/* write an object ID to a ASN1 buffer */
bool asn1_write_OID(struct asn1_data *data, const char *OID)
{
DATA_BLOB blob;
if (!asn1_push_tag(data, ASN1_OID)) return false;
if (!ber_write_OID_String(NULL, &blob, OID)) {
data->has_error = true;
return false;
}
if (!asn1_write(data, blob.data, blob.length)) {
data_blob_free(&blob);
data->has_error = true;
return false;
}
data_blob_free(&blob);
return asn1_pop_tag(data);
}
/* write an octet string */
bool asn1_write_OctetString(struct asn1_data *data, const void *p, size_t length)
{
if (!asn1_push_tag(data, ASN1_OCTET_STRING)) return false;
if (!asn1_write(data, p, length)) return false;
return asn1_pop_tag(data);
}
/* write a LDAP string */
bool asn1_write_LDAPString(struct asn1_data *data, const char *s)
{
return asn1_write(data, s, strlen(s));
}
/* write a LDAP string from a DATA_BLOB */
bool asn1_write_DATA_BLOB_LDAPString(struct asn1_data *data, const DATA_BLOB *s)
{
return asn1_write(data, s->data, s->length);
}
/* write a general string */
bool asn1_write_GeneralString(struct asn1_data *data, const char *s)
{
if (!asn1_push_tag(data, ASN1_GENERAL_STRING)) return false;
if (!asn1_write_LDAPString(data, s)) return false;
return asn1_pop_tag(data);
}
bool asn1_write_ContextSimple(struct asn1_data *data, uint8_t num, DATA_BLOB *blob)
{
if (!asn1_push_tag(data, ASN1_CONTEXT_SIMPLE(num))) return false;
if (!asn1_write(data, blob->data, blob->length)) return false;
return asn1_pop_tag(data);
}
/* write a BOOLEAN */
bool asn1_write_BOOLEAN(struct asn1_data *data, bool v)
{
if (!asn1_push_tag(data, ASN1_BOOLEAN)) return false;
if (!asn1_write_uint8(data, v ? 0xFF : 0)) return false;
return asn1_pop_tag(data);
}
bool asn1_read_BOOLEAN(struct asn1_data *data, bool *v)
{
uint8_t tmp = 0;
if (!asn1_start_tag(data, ASN1_BOOLEAN)) return false;
*v = false;
if (!asn1_read_uint8(data, &tmp)) return false;
if (tmp == 0xFF) {
*v = true;
}
return asn1_end_tag(data);
}
/* write a BOOLEAN in a simple context */
bool asn1_write_BOOLEAN_context(struct asn1_data *data, bool v, int context)
{
if (!asn1_push_tag(data, ASN1_CONTEXT_SIMPLE(context))) return false;
if (!asn1_write_uint8(data, v ? 0xFF : 0)) return false;
return asn1_pop_tag(data);
}
bool asn1_read_BOOLEAN_context(struct asn1_data *data, bool *v, int context)
{
uint8_t tmp = 0;
if (!asn1_start_tag(data, ASN1_CONTEXT_SIMPLE(context))) return false;
*v = false;
if (!asn1_read_uint8(data, &tmp)) return false;
if (tmp == 0xFF) {
*v = true;
}
return asn1_end_tag(data);
}
/* check a BOOLEAN */
bool asn1_check_BOOLEAN(struct asn1_data *data, bool v)
{
uint8_t b = 0;
if (!asn1_read_uint8(data, &b)) return false;
if (b != ASN1_BOOLEAN) {
data->has_error = true;
return false;
}
if (!asn1_read_uint8(data, &b)) return false;
if (b != v) {
data->has_error = true;
return false;
}
return !data->has_error;
}
/* load a struct asn1_data structure with a lump of data, ready to be parsed */
bool asn1_load(struct asn1_data *data, DATA_BLOB blob)
{
ZERO_STRUCTP(data);
data->data = (uint8_t *)talloc_memdup(data, blob.data, blob.length);
if (!data->data) {
data->has_error = true;
return false;
}
data->length = blob.length;
return true;
}
/* Peek into an ASN1 buffer, not advancing the pointer */
bool asn1_peek(struct asn1_data *data, void *p, int len)
{
if (data->has_error)
return false;
if (len < 0 || data->ofs + len < data->ofs || data->ofs + len < len)
return false;
if (data->ofs + len > data->length) {
/* we need to mark the buffer as consumed, so the caller knows
this was an out of data error, and not a decode error */
data->ofs = data->length;
return false;
}
memcpy(p, data->data + data->ofs, len);
return true;
}
/* read from a ASN1 buffer, advancing the buffer pointer */
bool asn1_read(struct asn1_data *data, void *p, int len)
{
if (!asn1_peek(data, p, len)) {
data->has_error = true;
return false;
}
data->ofs += len;
return true;
}
/* read a uint8_t from a ASN1 buffer */
bool asn1_read_uint8(struct asn1_data *data, uint8_t *v)
{
return asn1_read(data, v, 1);
}
bool asn1_peek_uint8(struct asn1_data *data, uint8_t *v)
{
return asn1_peek(data, v, 1);
}
bool asn1_peek_tag(struct asn1_data *data, uint8_t tag)
{
uint8_t b;
if (asn1_tag_remaining(data) <= 0) {
return false;
}
if (!asn1_peek_uint8(data, &b))
return false;
return (b == tag);
}
/*
* just get the needed size the tag would consume
*/
bool asn1_peek_tag_needed_size(struct asn1_data *data, uint8_t tag, size_t *size)
{
off_t start_ofs = data->ofs;
uint8_t b;
size_t taglen = 0;
if (data->has_error) {
return false;
}
if (!asn1_read_uint8(data, &b)) {
data->ofs = start_ofs;
data->has_error = false;
return false;
}
if (b != tag) {
data->ofs = start_ofs;
data->has_error = false;
return false;
}
if (!asn1_read_uint8(data, &b)) {
data->ofs = start_ofs;
data->has_error = false;
return false;
}
if (b & 0x80) {
int n = b & 0x7f;
if (!asn1_read_uint8(data, &b)) {
data->ofs = start_ofs;
data->has_error = false;
return false;
}
if (n > 4) {
/*
* We should not allow more than 4 bytes
* for the encoding of the tag length.
*
* Otherwise we'd overflow the taglen
* variable on 32 bit systems.
*/
data->ofs = start_ofs;
data->has_error = false;
return false;
}
taglen = b;
while (n > 1) {
if (!asn1_read_uint8(data, &b)) {
data->ofs = start_ofs;
data->has_error = false;
return false;
}
taglen = (taglen << 8) | b;
n--;
}
} else {
taglen = b;
}
*size = (data->ofs - start_ofs) + taglen;
data->ofs = start_ofs;
data->has_error = false;
return true;
}
/* start reading a nested asn1 structure */
bool asn1_start_tag(struct asn1_data *data, uint8_t tag)
{
uint8_t b;
struct nesting *nesting;
if (!asn1_read_uint8(data, &b))
return false;
if (b != tag) {
data->has_error = true;
return false;
}
nesting = talloc(data, struct nesting);
if (!nesting) {
data->has_error = true;
return false;
}
if (!asn1_read_uint8(data, &b)) {
return false;
}
if (b & 0x80) {
int n = b & 0x7f;
if (!asn1_read_uint8(data, &b))
return false;
nesting->taglen = b;
while (n > 1) {
if (!asn1_read_uint8(data, &b))
return false;
nesting->taglen = (nesting->taglen << 8) | b;
n--;
}
} else {
nesting->taglen = b;
}
nesting->start = data->ofs;
nesting->next = data->nesting;
data->nesting = nesting;
if (asn1_tag_remaining(data) == -1) {
return false;
}
return !data->has_error;
}
/* stop reading a tag */
bool asn1_end_tag(struct asn1_data *data)
{
struct nesting *nesting;
/* make sure we read it all */
if (asn1_tag_remaining(data) != 0) {
data->has_error = true;
return false;
}
nesting = data->nesting;
if (!nesting) {
data->has_error = true;
return false;
}
data->nesting = nesting->next;
talloc_free(nesting);
return true;
}
/* work out how many bytes are left in this nested tag */
int asn1_tag_remaining(struct asn1_data *data)
{
int remaining;
if (data->has_error) {
return -1;
}
if (!data->nesting) {
data->has_error = true;
return -1;
}
remaining = data->nesting->taglen - (data->ofs - data->nesting->start);
if (remaining > (data->length - data->ofs)) {
data->has_error = true;
return -1;
}
return remaining;
}
/**
* Internal implementation for reading binary OIDs
* Reading is done as far in the buffer as valid OID
* till buffer ends or not valid sub-identifier is found.
*/
static bool _ber_read_OID_String_impl(TALLOC_CTX *mem_ctx, DATA_BLOB blob,
char **OID, size_t *bytes_eaten)
{
int i;
uint8_t *b;
unsigned int v;
char *tmp_oid = NULL;
if (blob.length < 2) return false;
b = blob.data;
tmp_oid = talloc_asprintf(mem_ctx, "%u", b[0]/40);
if (!tmp_oid) goto nomem;
tmp_oid = talloc_asprintf_append_buffer(tmp_oid, ".%u", b[0]%40);
if (!tmp_oid) goto nomem;
if (bytes_eaten != NULL) {
*bytes_eaten = 0;
}
for(i = 1, v = 0; i < blob.length; i++) {
v = (v<<7) | (b[i]&0x7f);
if ( ! (b[i] & 0x80)) {
tmp_oid = talloc_asprintf_append_buffer(tmp_oid, ".%u", v);
v = 0;
if (bytes_eaten)
*bytes_eaten = i+1;
}
if (!tmp_oid) goto nomem;
}
*OID = tmp_oid;
return true;
nomem:
return false;
}
/* read an object ID from a data blob */
bool ber_read_OID_String(TALLOC_CTX *mem_ctx, DATA_BLOB blob, char **OID)
{
size_t bytes_eaten;
if (!_ber_read_OID_String_impl(mem_ctx, blob, OID, &bytes_eaten))
return false;
return (bytes_eaten == blob.length);
}
/**
* Deserialize partial OID string.
* Partial OIDs are in the form:
* 1:2.5.6:0x81
* 1:2.5.6:0x8182
*/
bool ber_read_partial_OID_String(TALLOC_CTX *mem_ctx, DATA_BLOB blob,
char **partial_oid)
{
size_t bytes_left;
size_t bytes_eaten;
char *identifier = NULL;
char *tmp_oid = NULL;
if (!_ber_read_OID_String_impl(mem_ctx, blob, &tmp_oid, &bytes_eaten))
return false;
if (bytes_eaten < blob.length) {
bytes_left = blob.length - bytes_eaten;
identifier = hex_encode_talloc(mem_ctx, &blob.data[bytes_eaten], bytes_left);
if (!identifier) goto nomem;
*partial_oid = talloc_asprintf_append_buffer(tmp_oid, ":0x%s", identifier);
if (!*partial_oid) goto nomem;
TALLOC_FREE(identifier);
} else {
*partial_oid = tmp_oid;
}
return true;
nomem:
TALLOC_FREE(identifier);
TALLOC_FREE(tmp_oid);
return false;
}
/* read an object ID from a ASN1 buffer */
bool asn1_read_OID(struct asn1_data *data, TALLOC_CTX *mem_ctx, char **OID)
{
DATA_BLOB blob;
int len;
if (!asn1_start_tag(data, ASN1_OID)) return false;
len = asn1_tag_remaining(data);
if (len < 0) {
data->has_error = true;
return false;
}
blob = data_blob(NULL, len);
if (!blob.data) {
data->has_error = true;
return false;
}
if (!asn1_read(data, blob.data, len)) return false;
if (!asn1_end_tag(data)) {
data_blob_free(&blob);
return false;
}
if (!ber_read_OID_String(mem_ctx, blob, OID)) {
data->has_error = true;
data_blob_free(&blob);
return false;
}
data_blob_free(&blob);
return true;
}
/* check that the next object ID is correct */
bool asn1_check_OID(struct asn1_data *data, const char *OID)
{
char *id;
if (!asn1_read_OID(data, data, &id)) return false;
if (strcmp(id, OID) != 0) {
talloc_free(id);
data->has_error = true;
return false;
}
talloc_free(id);
return true;
}
/* read a LDAPString from a ASN1 buffer */
bool asn1_read_LDAPString(struct asn1_data *data, TALLOC_CTX *mem_ctx, char **s)
{
int len;
len = asn1_tag_remaining(data);
if (len < 0) {
data->has_error = true;
return false;
}
*s = talloc_array(mem_ctx, char, len+1);
if (! *s) {
data->has_error = true;
return false;
}
(*s)[len] = 0;
return asn1_read(data, *s, len);
}
/* read a GeneralString from a ASN1 buffer */
bool asn1_read_GeneralString(struct asn1_data *data, TALLOC_CTX *mem_ctx, char **s)
{
if (!asn1_start_tag(data, ASN1_GENERAL_STRING)) return false;
if (!asn1_read_LDAPString(data, mem_ctx, s)) return false;
return asn1_end_tag(data);
}
/* read a octet string blob */
bool asn1_read_OctetString(struct asn1_data *data, TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
{
int len;
ZERO_STRUCTP(blob);
if (!asn1_start_tag(data, ASN1_OCTET_STRING)) return false;
len = asn1_tag_remaining(data);
if (len < 0) {
data->has_error = true;
return false;
}
*blob = data_blob_talloc(mem_ctx, NULL, len+1);
if (!blob->data || blob->length < len) {
data->has_error = true;
return false;
}
if (!asn1_read(data, blob->data, len)) goto err;
if (!asn1_end_tag(data)) goto err;
blob->length--;
blob->data[len] = 0;
return true;
err:
data_blob_free(blob);
*blob = data_blob_null;
return false;
}
bool asn1_read_ContextSimple(struct asn1_data *data, uint8_t num, DATA_BLOB *blob)
{
int len;
ZERO_STRUCTP(blob);
if (!asn1_start_tag(data, ASN1_CONTEXT_SIMPLE(num))) return false;
len = asn1_tag_remaining(data);
if (len < 0) {
data->has_error = true;
return false;
}
*blob = data_blob(NULL, len);
if ((len != 0) && (!blob->data)) {
data->has_error = true;
return false;
}
if (!asn1_read(data, blob->data, len)) return false;
return asn1_end_tag(data);
}
/* read an integer without tag*/
bool asn1_read_implicit_Integer(struct asn1_data *data, int *i)
{
uint8_t b;
bool first_byte = true;
*i = 0;
while (!data->has_error && asn1_tag_remaining(data)>0) {
if (!asn1_read_uint8(data, &b)) return false;
if (first_byte) {
if (b & 0x80) {
/* Number is negative.
Set i to -1 for sign extend. */
*i = -1;
}
first_byte = false;
}
*i = (*i << 8) + b;
}
return !data->has_error;
}
/* read an integer */
bool asn1_read_Integer(struct asn1_data *data, int *i)
{
*i = 0;
if (!asn1_start_tag(data, ASN1_INTEGER)) return false;
if (!asn1_read_implicit_Integer(data, i)) return false;
return asn1_end_tag(data);
}
/* read a BIT STRING */
bool asn1_read_BitString(struct asn1_data *data, TALLOC_CTX *mem_ctx, DATA_BLOB *blob, uint8_t *padding)
{
int len;
ZERO_STRUCTP(blob);
if (!asn1_start_tag(data, ASN1_BIT_STRING)) return false;
len = asn1_tag_remaining(data);
if (len < 0) {
data->has_error = true;
return false;
}
if (!asn1_read_uint8(data, padding)) return false;
*blob = data_blob_talloc(mem_ctx, NULL, len+1);
if (!blob->data || blob->length < len) {
data->has_error = true;
return false;
}
if (asn1_read(data, blob->data, len - 1)) {
blob->length--;
blob->data[len] = 0;
asn1_end_tag(data);
}
if (data->has_error) {
data_blob_free(blob);
*blob = data_blob_null;
*padding = 0;
return false;
}
return true;
}
/* read an integer */
bool asn1_read_enumerated(struct asn1_data *data, int *v)
{
*v = 0;
if (!asn1_start_tag(data, ASN1_ENUMERATED)) return false;
while (!data->has_error && asn1_tag_remaining(data)>0) {
uint8_t b;
asn1_read_uint8(data, &b);
*v = (*v << 8) + b;
}
return asn1_end_tag(data);
}
/* check a enumerated value is correct */
bool asn1_check_enumerated(struct asn1_data *data, int v)
{
uint8_t b;
if (!asn1_start_tag(data, ASN1_ENUMERATED)) return false;
if (!asn1_read_uint8(data, &b)) return false;
if (!asn1_end_tag(data)) return false;
if (v != b)
data->has_error = false;
return !data->has_error;
}
/* write an enumerated value to the stream */
bool asn1_write_enumerated(struct asn1_data *data, uint8_t v)
{
if (!asn1_push_tag(data, ASN1_ENUMERATED)) return false;
if (!asn1_write_uint8(data, v)) return false;
return asn1_pop_tag(data);
}
/*
Get us the data just written without copying
*/
bool asn1_blob(const struct asn1_data *asn1, DATA_BLOB *blob)
{
if (asn1->has_error) {
return false;
}
if (asn1->nesting != NULL) {
return false;
}
blob->data = asn1->data;
blob->length = asn1->length;
return true;
}
/*
Fill in an asn1 struct without making a copy
*/
void asn1_load_nocopy(struct asn1_data *data, uint8_t *buf, size_t len)
{
ZERO_STRUCTP(data);
data->data = buf;
data->length = len;
}
/*
check if a ASN.1 blob is a full tag
*/
NTSTATUS asn1_full_tag(DATA_BLOB blob, uint8_t tag, size_t *packet_size)
{
struct asn1_data *asn1 = asn1_init(NULL);
int size;
NT_STATUS_HAVE_NO_MEMORY(asn1);
asn1->data = blob.data;
asn1->length = blob.length;
if (!asn1_start_tag(asn1, tag)) {
talloc_free(asn1);
return STATUS_MORE_ENTRIES;
}
size = asn1_tag_remaining(asn1) + asn1->ofs;
talloc_free(asn1);
if (size > blob.length) {
return STATUS_MORE_ENTRIES;
}
*packet_size = size;
return NT_STATUS_OK;
}
NTSTATUS asn1_peek_full_tag(DATA_BLOB blob, uint8_t tag, size_t *packet_size)
{
struct asn1_data asn1;
size_t size;
bool ok;
ZERO_STRUCT(asn1);
asn1.data = blob.data;
asn1.length = blob.length;
ok = asn1_peek_tag_needed_size(&asn1, tag, &size);
if (!ok) {
return NT_STATUS_INVALID_BUFFER_SIZE;
}
if (size > blob.length) {
*packet_size = size;
return STATUS_MORE_ENTRIES;
}
*packet_size = size;
return NT_STATUS_OK;
}