OpenE2K
/
qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity
qemu-e2k/crypto/der.c

453 lines
14 KiB
C
Raw Blame History

/*
* QEMU Crypto ASN.1 DER decoder
*
* Copyright (c) 2022 Bytedance
* Author: lei he <helei.sig11@bytedance.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "crypto/der.h"
typedef struct QCryptoDerEncodeNode {
uint8_t tag;
struct QCryptoDerEncodeNode *parent;
struct QCryptoDerEncodeNode *next;
/* for constructed type, data is null */
const uint8_t *data;
size_t dlen;
} QCryptoDerEncodeNode;
typedef struct QCryptoEncodeContext {
QCryptoDerEncodeNode root;
QCryptoDerEncodeNode *current_parent;
QCryptoDerEncodeNode *tail;
} QCryptoEncodeContext;
enum QCryptoDERTypeTag {
QCRYPTO_DER_TYPE_TAG_BOOL = 0x1,
QCRYPTO_DER_TYPE_TAG_INT = 0x2,
QCRYPTO_DER_TYPE_TAG_BIT_STR = 0x3,
QCRYPTO_DER_TYPE_TAG_OCT_STR = 0x4,
QCRYPTO_DER_TYPE_TAG_NULL = 0x5,
QCRYPTO_DER_TYPE_TAG_OID = 0x6,
QCRYPTO_DER_TYPE_TAG_SEQ = 0x10,
QCRYPTO_DER_TYPE_TAG_SET = 0x11,
};
enum QCryptoDERTagClass {
QCRYPTO_DER_TAG_CLASS_UNIV = 0x0,
QCRYPTO_DER_TAG_CLASS_APPL = 0x1,
QCRYPTO_DER_TAG_CLASS_CONT = 0x2,
QCRYPTO_DER_TAG_CLASS_PRIV = 0x3,
};
enum QCryptoDERTagEnc {
QCRYPTO_DER_TAG_ENC_PRIM = 0x0,
QCRYPTO_DER_TAG_ENC_CONS = 0x1,
};
#define QCRYPTO_DER_TAG_ENC_MASK 0x20
#define QCRYPTO_DER_TAG_ENC_SHIFT 5
#define QCRYPTO_DER_TAG_CLASS_MASK 0xc0
#define QCRYPTO_DER_TAG_CLASS_SHIFT 6
#define QCRYPTO_DER_TAG_VAL_MASK 0x1f
#define QCRYPTO_DER_SHORT_LEN_MASK 0x80
#define QCRYPTO_DER_TAG(class, enc, val) \
(((class) << QCRYPTO_DER_TAG_CLASS_SHIFT) | \
((enc) << QCRYPTO_DER_TAG_ENC_SHIFT) | (val))
/**
* qcrypto_der_encode_length:
* @src_len: the length of source data
* @dst: distination to save the encoded 'length', if dst is NULL, only compute
* the expected buffer size in bytes.
* @dst_len: output parameter, indicates how many bytes wrote.
*
* Encode the 'length' part of TLV tuple.
*/
static void qcrypto_der_encode_length(size_t src_len,
uint8_t *dst, size_t *dst_len)
{
size_t max_length = 0xFF;
uint8_t length_bytes = 0, header_byte;
if (src_len < QCRYPTO_DER_SHORT_LEN_MASK) {
header_byte = src_len;
*dst_len = 1;
} else {
for (length_bytes = 1; max_length < src_len; length_bytes++) {
max_length = (max_length << 8) + max_length;
}
header_byte = length_bytes;
header_byte |= QCRYPTO_DER_SHORT_LEN_MASK;
*dst_len = length_bytes + 1;
}
if (!dst) {
return;
}
*dst++ = header_byte;
/* Bigendian length bytes */
for (; length_bytes > 0; length_bytes--) {
*dst++ = ((src_len >> (length_bytes - 1) * 8) & 0xFF);
}
}
static uint8_t qcrypto_der_peek_byte(const uint8_t **data, size_t *dlen)
{
return **data;
}
static void qcrypto_der_cut_nbytes(const uint8_t **data,
size_t *dlen,
size_t nbytes)
{
*data += nbytes;
*dlen -= nbytes;
}
static uint8_t qcrypto_der_cut_byte(const uint8_t **data, size_t *dlen)
{
uint8_t val = qcrypto_der_peek_byte(data, dlen);
qcrypto_der_cut_nbytes(data, dlen, 1);
return val;
}
static int qcrypto_der_invoke_callback(QCryptoDERDecodeCb cb, void *ctx,
const uint8_t *value, size_t vlen,
Error **errp)
{
if (!cb) {
return 0;
}
return cb(ctx, value, vlen, errp);
}
static int qcrypto_der_extract_definite_data(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx,
Error **errp)
{
const uint8_t *value;
size_t vlen = 0;
uint8_t byte_count = qcrypto_der_cut_byte(data, dlen);
/* short format of definite-length */
if (!(byte_count & QCRYPTO_DER_SHORT_LEN_MASK)) {
if (byte_count > *dlen) {
error_setg(errp, "Invalid content length: %u", byte_count);
return -1;
}
value = *data;
vlen = byte_count;
qcrypto_der_cut_nbytes(data, dlen, vlen);
if (qcrypto_der_invoke_callback(cb, ctx, value, vlen, errp) != 0) {
return -1;
}
return vlen;
}
/* Ignore highest bit */
byte_count &= ~QCRYPTO_DER_SHORT_LEN_MASK;
/*
* size_t is enough to store the value of length, although the DER
* encoding standard supports larger length.
*/
if (byte_count > sizeof(size_t)) {
error_setg(errp, "Invalid byte count of content length: %u",
byte_count);
return -1;
}
if (byte_count > *dlen) {
error_setg(errp, "Invalid content length: %u", byte_count);
return -1;
}
while (byte_count--) {
vlen <<= 8;
vlen += qcrypto_der_cut_byte(data, dlen);
}
if (vlen > *dlen) {
error_setg(errp, "Invalid content length: %zu", vlen);
return -1;
}
value = *data;
qcrypto_der_cut_nbytes(data, dlen, vlen);
if (qcrypto_der_invoke_callback(cb, ctx, value, vlen, errp) != 0) {
return -1;
}
return vlen;
}
static int qcrypto_der_extract_data(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx,
Error **errp)
{
uint8_t val;
if (*dlen < 1) {
error_setg(errp, "Need more data");
return -1;
}
val = qcrypto_der_peek_byte(data, dlen);
/* must use definite length format */
if (val == QCRYPTO_DER_SHORT_LEN_MASK) {
error_setg(errp, "Only definite length format is allowed");
return -1;
}
return qcrypto_der_extract_definite_data(data, dlen, cb, ctx, errp);
}
static int qcrypto_der_decode_tlv(const uint8_t expected_tag,
const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb,
void *ctx, Error **errp)
{
const uint8_t *saved_data = *data;
size_t saved_dlen = *dlen;
uint8_t tag;
int data_length;
if (*dlen < 1) {
error_setg(errp, "Need more data");
return -1;
}
tag = qcrypto_der_cut_byte(data, dlen);
if (tag != expected_tag) {
error_setg(errp, "Unexpected tag: expected: %u, actual: %u",
expected_tag, tag);
goto error;
}
data_length = qcrypto_der_extract_data(data, dlen, cb, ctx, errp);
if (data_length < 0) {
goto error;
}
return data_length;
error:
*data = saved_data;
*dlen = saved_dlen;
return -1;
}
int qcrypto_der_decode_int(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx, Error **errp)
{
const uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_INT);
return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
}
int qcrypto_der_decode_seq(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx, Error **errp)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_CONS,
QCRYPTO_DER_TYPE_TAG_SEQ);
return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
}
int qcrypto_der_decode_octet_str(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx, Error **errp)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_OCT_STR);
return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
}
int qcrypto_der_decode_bit_str(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx, Error **errp)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_BIT_STR);
return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
}
int qcrypto_der_decode_oid(const uint8_t **data, size_t *dlen,
QCryptoDERDecodeCb cb, void *ctx, Error **errp)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_OID);
return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
}
int qcrypto_der_decode_ctx_tag(const uint8_t **data, size_t *dlen, int tag_id,
QCryptoDERDecodeCb cb, void *ctx, Error **errp)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_CONT,
QCRYPTO_DER_TAG_ENC_CONS,
tag_id);
return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
}
static void qcrypto_der_encode_prim(QCryptoEncodeContext *ctx, uint8_t tag,
const uint8_t *data, size_t dlen)
{
QCryptoDerEncodeNode *node = g_new0(QCryptoDerEncodeNode, 1);
size_t nbytes_len;
node->tag = tag;
node->data = data;
node->dlen = dlen;
node->parent = ctx->current_parent;
qcrypto_der_encode_length(dlen, NULL, &nbytes_len);
/* 1 byte for Tag, nbyte_len for Length, and dlen for Value */
node->parent->dlen += 1 + nbytes_len + dlen;
ctx->tail->next = node;
ctx->tail = node;
}
QCryptoEncodeContext *qcrypto_der_encode_ctx_new(void)
{
QCryptoEncodeContext *ctx = g_new0(QCryptoEncodeContext, 1);
ctx->current_parent = &ctx->root;
ctx->tail = &ctx->root;
return ctx;
}
static void qcrypto_der_encode_cons_begin(QCryptoEncodeContext *ctx,
uint8_t tag)
{
QCryptoDerEncodeNode *node = g_new0(QCryptoDerEncodeNode, 1);
node->tag = tag;
node->parent = ctx->current_parent;
ctx->current_parent = node;
ctx->tail->next = node;
ctx->tail = node;
}
static void qcrypto_der_encode_cons_end(QCryptoEncodeContext *ctx)
{
QCryptoDerEncodeNode *cons_node = ctx->current_parent;
size_t nbytes_len;
qcrypto_der_encode_length(cons_node->dlen, NULL, &nbytes_len);
/* 1 byte for Tag, nbyte_len for Length, and dlen for Value */
cons_node->parent->dlen += 1 + nbytes_len + cons_node->dlen;
ctx->current_parent = cons_node->parent;
}
void qcrypto_der_encode_seq_begin(QCryptoEncodeContext *ctx)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_CONS,
QCRYPTO_DER_TYPE_TAG_SEQ);
qcrypto_der_encode_cons_begin(ctx, tag);
}
void qcrypto_der_encode_seq_end(QCryptoEncodeContext *ctx)
{
qcrypto_der_encode_cons_end(ctx);
}
void qcrypto_der_encode_oid(QCryptoEncodeContext *ctx,
const uint8_t *src, size_t src_len)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_OID);
qcrypto_der_encode_prim(ctx, tag, src, src_len);
}
void qcrypto_der_encode_int(QCryptoEncodeContext *ctx,
const uint8_t *src, size_t src_len)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_INT);
qcrypto_der_encode_prim(ctx, tag, src, src_len);
}
void qcrypto_der_encode_null(QCryptoEncodeContext *ctx)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_NULL);
qcrypto_der_encode_prim(ctx, tag, NULL, 0);
}
void qcrypto_der_encode_octet_str(QCryptoEncodeContext *ctx,
const uint8_t *src, size_t src_len)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_OCT_STR);
qcrypto_der_encode_prim(ctx, tag, src, src_len);
}
void qcrypto_der_encode_octet_str_begin(QCryptoEncodeContext *ctx)
{
uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
QCRYPTO_DER_TAG_ENC_PRIM,
QCRYPTO_DER_TYPE_TAG_OCT_STR);
qcrypto_der_encode_cons_begin(ctx, tag);
}
void qcrypto_der_encode_octet_str_end(QCryptoEncodeContext *ctx)
{
qcrypto_der_encode_cons_end(ctx);
}
size_t qcrypto_der_encode_ctx_buffer_len(QCryptoEncodeContext *ctx)
{
return ctx->root.dlen;
}
void qcrypto_der_encode_ctx_flush_and_free(QCryptoEncodeContext *ctx,
uint8_t *dst)
{
QCryptoDerEncodeNode *node, *prev;
size_t len;
for (prev = &ctx->root;
(node = prev->next) && (prev->next = node->next, 1);) {
/* Tag */
*dst++ = node->tag;
/* Length */
qcrypto_der_encode_length(node->dlen, dst, &len);
dst += len;
/* Value */
if (node->data) {
memcpy(dst, node->data, node->dlen);
dst += node->dlen;
}
g_free(node);
}
g_free(ctx);
}
Reference in New Issue View Git Blame Copy Permalink