[mirror_qemu.git] / crypto / der.c

/*
 * 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);
}
Commit	Line	Data
99d423f1 LH	1	/*
	2	* QEMU Crypto ASN.1 DER decoder
	3	*
	4	* Copyright (c) 2022 Bytedance
	5	* Author: lei he <helei.sig11@bytedance.com>
	6	*
	7	* This library is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU Lesser General Public
	9	* License as published by the Free Software Foundation; either
	10	* version 2.1 of the License, or (at your option) any later version.
	11	*
	12	* This library is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* Lesser General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU Lesser General Public
	18	* License along with this library; if not, see <http://www.gnu.org/licenses/>.
	19	*
	20	*/
	21
	22	#include "qemu/osdep.h"
	23	#include "crypto/der.h"
	24
3b34ccad LH	25	typedef struct QCryptoDerEncodeNode {
	26	uint8_t tag;
	27	struct QCryptoDerEncodeNode *parent;
	28	struct QCryptoDerEncodeNode *next;
	29	/* for constructed type, data is null */
	30	const uint8_t *data;
	31	size_t dlen;
	32	} QCryptoDerEncodeNode;
	33
	34	typedef struct QCryptoEncodeContext {
	35	QCryptoDerEncodeNode root;
	36	QCryptoDerEncodeNode *current_parent;
	37	QCryptoDerEncodeNode *tail;
	38	} QCryptoEncodeContext;
	39
99d423f1 LH	40	enum QCryptoDERTypeTag {
	41	QCRYPTO_DER_TYPE_TAG_BOOL = 0x1,
	42	QCRYPTO_DER_TYPE_TAG_INT = 0x2,
	43	QCRYPTO_DER_TYPE_TAG_BIT_STR = 0x3,
	44	QCRYPTO_DER_TYPE_TAG_OCT_STR = 0x4,
3b34ccad LH	45	QCRYPTO_DER_TYPE_TAG_NULL = 0x5,
3b34ccad LH	46	QCRYPTO_DER_TYPE_TAG_OID = 0x6,
99d423f1 LH	47	QCRYPTO_DER_TYPE_TAG_SEQ = 0x10,
	48	QCRYPTO_DER_TYPE_TAG_SET = 0x11,
	49	};
	50
3b34ccad LH	51	enum QCryptoDERTagClass {
	52	QCRYPTO_DER_TAG_CLASS_UNIV = 0x0,
	53	QCRYPTO_DER_TAG_CLASS_APPL = 0x1,
	54	QCRYPTO_DER_TAG_CLASS_CONT = 0x2,
	55	QCRYPTO_DER_TAG_CLASS_PRIV = 0x3,
	56	};
	57
	58	enum QCryptoDERTagEnc {
	59	QCRYPTO_DER_TAG_ENC_PRIM = 0x0,
	60	QCRYPTO_DER_TAG_ENC_CONS = 0x1,
	61	};
	62
	63	#define QCRYPTO_DER_TAG_ENC_MASK 0x20
	64	#define QCRYPTO_DER_TAG_ENC_SHIFT 5
	65
	66	#define QCRYPTO_DER_TAG_CLASS_MASK 0xc0
	67	#define QCRYPTO_DER_TAG_CLASS_SHIFT 6
	68
	69	#define QCRYPTO_DER_TAG_VAL_MASK 0x1f
99d423f1 LH	70	#define QCRYPTO_DER_SHORT_LEN_MASK 0x80
99d423f1 LH	71
3b34ccad LH	72	#define QCRYPTO_DER_TAG(class, enc, val) \
	73	(((class) << QCRYPTO_DER_TAG_CLASS_SHIFT) \| \
	74	((enc) << QCRYPTO_DER_TAG_ENC_SHIFT) \| (val))
	75
	76	/**
	77	* qcrypto_der_encode_length:
	78	* @src_len: the length of source data
	79	* @dst: distination to save the encoded 'length', if dst is NULL, only compute
	80	* the expected buffer size in bytes.
	81	* @dst_len: output parameter, indicates how many bytes wrote.
	82	*
	83	* Encode the 'length' part of TLV tuple.
	84	*/
	85	static void qcrypto_der_encode_length(size_t src_len,
	86	uint8_t dst, size_t dst_len)
	87	{
	88	size_t max_length = 0xFF;
	89	uint8_t length_bytes = 0, header_byte;
	90
	91	if (src_len < QCRYPTO_DER_SHORT_LEN_MASK) {
	92	header_byte = src_len;
	93	*dst_len = 1;
	94	} else {
	95	for (length_bytes = 1; max_length < src_len; length_bytes++) {
	96	max_length = (max_length << 8) + max_length;
	97	}
	98	header_byte = length_bytes;
	99	header_byte \|= QCRYPTO_DER_SHORT_LEN_MASK;
	100	*dst_len = length_bytes + 1;
	101	}
	102	if (!dst) {
	103	return;
	104	}
	105	*dst++ = header_byte;
	106	/* Bigendian length bytes */
	107	for (; length_bytes > 0; length_bytes--) {
	108	dst++ = ((src_len >> (length_bytes - 1) 8) & 0xFF);
	109	}
	110	}
	111
99d423f1 LH	112	static uint8_t qcrypto_der_peek_byte(const uint8_t *data, size_t dlen)
	113	{
	114	return **data;
	115	}
	116
	117	static void qcrypto_der_cut_nbytes(const uint8_t **data,
	118	size_t *dlen,
	119	size_t nbytes)
	120	{
	121	*data += nbytes;
	122	*dlen -= nbytes;
	123	}
	124
	125	static uint8_t qcrypto_der_cut_byte(const uint8_t *data, size_t dlen)
	126	{
	127	uint8_t val = qcrypto_der_peek_byte(data, dlen);
	128
	129	qcrypto_der_cut_nbytes(data, dlen, 1);
	130
	131	return val;
	132	}
	133
	134	static int qcrypto_der_invoke_callback(QCryptoDERDecodeCb cb, void *ctx,
	135	const uint8_t *value, size_t vlen,
	136	Error **errp)
	137	{
	138	if (!cb) {
	139	return 0;
	140	}
	141
	142	return cb(ctx, value, vlen, errp);
	143	}
	144
	145	static int qcrypto_der_extract_definite_data(const uint8_t *data, size_t dlen,
	146	QCryptoDERDecodeCb cb, void *ctx,
	147	Error **errp)
	148	{
	149	const uint8_t *value;
	150	size_t vlen = 0;
	151	uint8_t byte_count = qcrypto_der_cut_byte(data, dlen);
	152
	153	/* short format of definite-length */
	154	if (!(byte_count & QCRYPTO_DER_SHORT_LEN_MASK)) {
	155	if (byte_count > *dlen) {
	156	error_setg(errp, "Invalid content length: %u", byte_count);
	157	return -1;
	158	}
	159
	160	value = *data;
	161	vlen = byte_count;
	162	qcrypto_der_cut_nbytes(data, dlen, vlen);
	163
	164	if (qcrypto_der_invoke_callback(cb, ctx, value, vlen, errp) != 0) {
	165	return -1;
	166	}
	167	return vlen;
	168	}
	169
	170	/* Ignore highest bit */
	171	byte_count &= ~QCRYPTO_DER_SHORT_LEN_MASK;
	172
	173	/*
	174	* size_t is enough to store the value of length, although the DER
	175	* encoding standard supports larger length.
176	*/
177	if (byte_count > sizeof(size_t)) {
178	error_setg(errp, "Invalid byte count of content length: %u",
179	byte_count);
180	return -1;
181	}
182
183	if (byte_count > *dlen) {
184	error_setg(errp, "Invalid content length: %u", byte_count);
185	return -1;
186	}
187	while (byte_count--) {
188	vlen <<= 8;
189	vlen += qcrypto_der_cut_byte(data, dlen);
190	}
191
192	if (vlen > *dlen) {
193	error_setg(errp, "Invalid content length: %zu", vlen);
194	return -1;
195	}
196
197	value = *data;
198	qcrypto_der_cut_nbytes(data, dlen, vlen);
199
200	if (qcrypto_der_invoke_callback(cb, ctx, value, vlen, errp) != 0) {
201	return -1;
202	}
203	return vlen;
204	}
205
206	static int qcrypto_der_extract_data(const uint8_t *data, size_t dlen,
207	QCryptoDERDecodeCb cb, void *ctx,
208	Error **errp)
209	{
210	uint8_t val;
211	if (*dlen < 1) {
212	error_setg(errp, "Need more data");
213	return -1;
214	}
215	val = qcrypto_der_peek_byte(data, dlen);
216
217	/* must use definite length format */
218	if (val == QCRYPTO_DER_SHORT_LEN_MASK) {
219	error_setg(errp, "Only definite length format is allowed");
220	return -1;
221	}
222
223	return qcrypto_der_extract_definite_data(data, dlen, cb, ctx, errp);
224	}
225
3b34ccad LH	226	static int qcrypto_der_decode_tlv(const uint8_t expected_tag,
	227	const uint8_t *data, size_t dlen,
	228	QCryptoDERDecodeCb cb,
	229	void ctx, Error *errp)
99d423f1	230	{
3b34ccad LH	231	const uint8_t saved_data = data;
3b34ccad LH	232	size_t saved_dlen = *dlen;
99d423f1	233	uint8_t tag;
3b34ccad LH	234	int data_length;
3b34ccad LH	235
99d423f1 LH	236	if (*dlen < 1) {
	237	error_setg(errp, "Need more data");
	238	return -1;
	239	}
	240	tag = qcrypto_der_cut_byte(data, dlen);
3b34ccad LH	241	if (tag != expected_tag) {
	242	error_setg(errp, "Unexpected tag: expected: %u, actual: %u",
	243	expected_tag, tag);
	244	goto error;
	245	}
99d423f1	246
3b34ccad LH	247	data_length = qcrypto_der_extract_data(data, dlen, cb, ctx, errp);
	248	if (data_length < 0) {
	249	goto error;
99d423f1	250	}
3b34ccad	251	return data_length;
99d423f1	252
3b34ccad LH	253	error:
	254	*data = saved_data;
	255	*dlen = saved_dlen;
	256	return -1;
	257	}
	258
	259	int qcrypto_der_decode_int(const uint8_t *data, size_t dlen,
	260	QCryptoDERDecodeCb cb, void ctx, Error *errp)
	261	{
	262	const uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
	263	QCRYPTO_DER_TAG_ENC_PRIM,
	264	QCRYPTO_DER_TYPE_TAG_INT);
	265	return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
99d423f1 LH	266	}
	267
	268	int qcrypto_der_decode_seq(const uint8_t *data, size_t dlen,
	269	QCryptoDERDecodeCb cb, void ctx, Error *errp)
	270	{
3b34ccad LH	271	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
	272	QCRYPTO_DER_TAG_ENC_CONS,
	273	QCRYPTO_DER_TYPE_TAG_SEQ);
	274	return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
	275	}
99d423f1	276
3b34ccad LH	277	int qcrypto_der_decode_octet_str(const uint8_t *data, size_t dlen,
	278	QCryptoDERDecodeCb cb, void ctx, Error *errp)
	279	{
	280	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
	281	QCRYPTO_DER_TAG_ENC_PRIM,
	282	QCRYPTO_DER_TYPE_TAG_OCT_STR);
	283	return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
	284	}
	285
	286	int qcrypto_der_decode_bit_str(const uint8_t *data, size_t dlen,
	287	QCryptoDERDecodeCb cb, void ctx, Error *errp)
	288	{
	289	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
	290	QCRYPTO_DER_TAG_ENC_PRIM,
	291	QCRYPTO_DER_TYPE_TAG_BIT_STR);
	292	return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
	293	}
	294
	295	int qcrypto_der_decode_oid(const uint8_t *data, size_t dlen,
	296	QCryptoDERDecodeCb cb, void ctx, Error *errp)
	297	{
	298	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
	299	QCRYPTO_DER_TAG_ENC_PRIM,
	300	QCRYPTO_DER_TYPE_TAG_OID);
	301	return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
	302	}
	303
	304	int qcrypto_der_decode_ctx_tag(const uint8_t *data, size_t dlen, int tag_id,
	305	QCryptoDERDecodeCb cb, void ctx, Error *errp)
	306	{
	307	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_CONT,
	308	QCRYPTO_DER_TAG_ENC_CONS,
	309	tag_id);
	310	return qcrypto_der_decode_tlv(tag, data, dlen, cb, ctx, errp);
	311	}
99d423f1	312
3b34ccad LH	313	static void qcrypto_der_encode_prim(QCryptoEncodeContext *ctx, uint8_t tag,
	314	const uint8_t *data, size_t dlen)
	315	{
	316	QCryptoDerEncodeNode *node = g_new0(QCryptoDerEncodeNode, 1);
	317	size_t nbytes_len;
	318
	319	node->tag = tag;
	320	node->data = data;
	321	node->dlen = dlen;
	322	node->parent = ctx->current_parent;
	323
	324	qcrypto_der_encode_length(dlen, NULL, &nbytes_len);
	325	/* 1 byte for Tag, nbyte_len for Length, and dlen for Value */
	326	node->parent->dlen += 1 + nbytes_len + dlen;
	327
	328	ctx->tail->next = node;
	329	ctx->tail = node;
	330	}
	331
	332	QCryptoEncodeContext *qcrypto_der_encode_ctx_new(void)
	333	{
	334	QCryptoEncodeContext *ctx = g_new0(QCryptoEncodeContext, 1);
	335	ctx->current_parent = &ctx->root;
	336	ctx->tail = &ctx->root;
	337	return ctx;
	338	}
	339
	340	static void qcrypto_der_encode_cons_begin(QCryptoEncodeContext *ctx,
	341	uint8_t tag)
	342	{
	343	QCryptoDerEncodeNode *node = g_new0(QCryptoDerEncodeNode, 1);
	344
	345	node->tag = tag;
	346	node->parent = ctx->current_parent;
	347	ctx->current_parent = node;
	348	ctx->tail->next = node;
	349	ctx->tail = node;
	350	}
	351
	352	static void qcrypto_der_encode_cons_end(QCryptoEncodeContext *ctx)
	353	{
	354	QCryptoDerEncodeNode *cons_node = ctx->current_parent;
	355	size_t nbytes_len;
	356
	357	qcrypto_der_encode_length(cons_node->dlen, NULL, &nbytes_len);
	358	/* 1 byte for Tag, nbyte_len for Length, and dlen for Value */
	359	cons_node->parent->dlen += 1 + nbytes_len + cons_node->dlen;
	360	ctx->current_parent = cons_node->parent;
	361	}
	362
	363	void qcrypto_der_encode_seq_begin(QCryptoEncodeContext *ctx)
	364	{
	365	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
	366	QCRYPTO_DER_TAG_ENC_CONS,
	367	QCRYPTO_DER_TYPE_TAG_SEQ);
	368	qcrypto_der_encode_cons_begin(ctx, tag);
	369	}
	370
	371	void qcrypto_der_encode_seq_end(QCryptoEncodeContext *ctx)
	372	{
	373	qcrypto_der_encode_cons_end(ctx);
	374	}
	375
	376	void qcrypto_der_encode_oid(QCryptoEncodeContext *ctx,
377	const uint8_t *src, size_t src_len)
378	{
379	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
380	QCRYPTO_DER_TAG_ENC_PRIM,
381	QCRYPTO_DER_TYPE_TAG_OID);
382	qcrypto_der_encode_prim(ctx, tag, src, src_len);
383	}
384
385	void qcrypto_der_encode_int(QCryptoEncodeContext *ctx,
386	const uint8_t *src, size_t src_len)
387	{
388	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
389	QCRYPTO_DER_TAG_ENC_PRIM,
390	QCRYPTO_DER_TYPE_TAG_INT);
391	qcrypto_der_encode_prim(ctx, tag, src, src_len);
392	}
393
394	void qcrypto_der_encode_null(QCryptoEncodeContext *ctx)
395	{
396	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
397	QCRYPTO_DER_TAG_ENC_PRIM,
398	QCRYPTO_DER_TYPE_TAG_NULL);
399	qcrypto_der_encode_prim(ctx, tag, NULL, 0);
400	}
401
402	void qcrypto_der_encode_octet_str(QCryptoEncodeContext *ctx,
403	const uint8_t *src, size_t src_len)
404	{
405	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
406	QCRYPTO_DER_TAG_ENC_PRIM,
407	QCRYPTO_DER_TYPE_TAG_OCT_STR);
408	qcrypto_der_encode_prim(ctx, tag, src, src_len);
409	}
410
411	void qcrypto_der_encode_octet_str_begin(QCryptoEncodeContext *ctx)
412	{
413	uint8_t tag = QCRYPTO_DER_TAG(QCRYPTO_DER_TAG_CLASS_UNIV,
414	QCRYPTO_DER_TAG_ENC_PRIM,
415	QCRYPTO_DER_TYPE_TAG_OCT_STR);
416	qcrypto_der_encode_cons_begin(ctx, tag);
417	}
418
419	void qcrypto_der_encode_octet_str_end(QCryptoEncodeContext *ctx)
420	{
421	qcrypto_der_encode_cons_end(ctx);
422	}
423
424	size_t qcrypto_der_encode_ctx_buffer_len(QCryptoEncodeContext *ctx)
425	{
426	return ctx->root.dlen;
427	}
428
429	void qcrypto_der_encode_ctx_flush_and_free(QCryptoEncodeContext *ctx,
430	uint8_t *dst)
431	{
432	QCryptoDerEncodeNode node, prev;
433	size_t len;
434
435	for (prev = &ctx->root;
436	(node = prev->next) && (prev->next = node->next, 1);) {
437	/* Tag */
438	*dst++ = node->tag;
439
440	/* Length */
441	qcrypto_der_encode_length(node->dlen, dst, &len);
442	dst += len;
443
444	/* Value */
445	if (node->data) {
446	memcpy(dst, node->data, node->dlen);
447	dst += node->dlen;
448	}
449	g_free(node);
450	}
451	g_free(ctx);
99d423f1	452	}