ldap_key_seq.c   [plain text]

/* ... copyright ... */

/* Novell key-format scheme:

   KrbKeySet ::= SEQUENCE {
   attribute-major-vno       [0] UInt16,
   attribute-minor-vno       [1] UInt16,
   kvno                      [2] UInt32,
   mkvno                     [3] UInt32 OPTIONAL,
   keys                      [4] SEQUENCE OF KrbKey,
   ...
   }

   KrbKey ::= SEQUENCE {
   salt      [0] KrbSalt OPTIONAL,
   key       [1] EncryptionKey,
   s2kparams [2] OCTET STRING OPTIONAL,
    ...
   }

   KrbSalt ::= SEQUENCE {
   type      [0] Int32,
   salt      [1] OCTET STRING OPTIONAL
   }

   EncryptionKey ::= SEQUENCE {
   keytype   [0] Int32,
   keyvalue  [1] OCTET STRING
   }

 */

#include <k5-int.h>
#include <kdb.h>

#include "krbasn1.h"
#include "asn1_encode.h"
#include "asn1_decode.h"
#include "asn1_make.h"
#include "asn1_get.h"

#define asn1_encode_sequence_of_keys krb5int_ldap_encode_sequence_of_keys
#define asn1_decode_sequence_of_keys krb5int_ldap_decode_sequence_of_keys

#define cleanup(err)							\
	{								\
		ret = err;						\
		goto last;						\
	}

#define checkerr							\
		if (ret != 0)						\
			goto last

/************************************************************************/
/* Encode the Principal's keys						*/
/************************************************************************/

static asn1_error_code
asn1_encode_key(asn1buf *buf,
		krb5_key_data key_data,
		unsigned int *retlen)
{
    asn1_error_code ret = 0;
    unsigned int length, sum = 0;

    /* Encode the key type and value.  */
    {
	unsigned int key_len = 0;
	/* key value */
	ret = asn1_encode_octetstring (buf,
				       key_data.key_data_length[0],
				       key_data.key_data_contents[0],
				       &length); checkerr;
	key_len += length;
	ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 1, length, &length); checkerr;
	key_len += length;
	/* key type */
	ret = asn1_encode_integer (buf, key_data.key_data_type[0], &length);
	checkerr;
	key_len += length;
	ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 0, length, &length); checkerr;
	key_len += length;

	ret = asn1_make_sequence(buf, key_len, &length); checkerr;
	key_len += length;
	ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 1, key_len, &length); checkerr;
	key_len += length;

	sum += key_len;
    }
    /* Encode the salt type and value (optional) */
    if (key_data.key_data_ver > 1) {
	unsigned int salt_len = 0;
	/* salt value (optional) */
	if (key_data.key_data_length[1] > 0) {
	    ret = asn1_encode_octetstring (buf,
					   key_data.key_data_length[1],
					   key_data.key_data_contents[1],
					   &length); checkerr;
	    salt_len += length;
	    ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 1, length, &length);
	    checkerr;
	    salt_len += length;
	}
	/* salt type */
	ret = asn1_encode_integer (buf, key_data.key_data_type[1], &length);
	checkerr;
	salt_len += length;
	ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 0, length, &length); checkerr;
	salt_len += length;

	ret = asn1_make_sequence(buf, salt_len, &length); checkerr;
	salt_len += length;
	ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 0, salt_len, &length); checkerr;
	salt_len += length;

	sum += salt_len;
    }

    ret = asn1_make_sequence(buf, sum, &length); checkerr;
    sum += length;

    *retlen = sum;

last:
    return ret;
}

/* Major version and minor version are both '1' - first version */
/* asn1_error_code asn1_encode_sequence_of_keys (krb5_key_data *key_data, */
krb5_error_code
asn1_encode_sequence_of_keys (krb5_key_data *key_data,
			      krb5_int16 n_key_data,
			      krb5_int32 mkvno,	/* Master key version number */
			      krb5_data **code)
{
    asn1_error_code ret = 0;
    asn1buf *buf = NULL;
    unsigned int length, sum = 0;
    unsigned long tmp_ul;

    *code = NULL;

    if (n_key_data == 0) cleanup (ASN1_MISSING_FIELD);

    /* Allocate the buffer */
    ret = asn1buf_create(&buf);
    checkerr;

    /* Sequence of keys */
    {
	int i;
	unsigned int seq_len = 0;

	for (i = n_key_data - 1; i >= 0; i--) {
	    ret = asn1_encode_key (buf, key_data[i], &length); checkerr;
	    seq_len += length;
	}
	ret = asn1_make_sequence(buf, seq_len, &length); checkerr;
	seq_len += length;
	ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 4, seq_len, &length); checkerr;
	seq_len += length;

	sum += seq_len;
    }

    /* mkvno */
    if (mkvno < 0)
	cleanup (ASN1_BAD_FORMAT);
    tmp_ul = (unsigned long)mkvno;
    ret = asn1_encode_unsigned_integer (buf, tmp_ul, &length); checkerr;
    sum += length;
    ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 3, length, &length); checkerr;
    sum += length;

    /* kvno (assuming all keys in array have same version) */
    if (key_data[0].key_data_kvno < 0)
	cleanup (ASN1_BAD_FORMAT);
    tmp_ul = (unsigned long)key_data[0].key_data_kvno;
    ret = asn1_encode_unsigned_integer (buf, tmp_ul, &length);
    checkerr;
    sum += length;
    ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 2, length, &length); checkerr;
    sum += length;

    /* attribute-minor-vno == 1 */
    ret = asn1_encode_unsigned_integer (buf, 1, &length); checkerr;
    sum += length;
    ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 1, length, &length); checkerr;
    sum += length;

    /* attribute-major-vno == 1 */
    ret = asn1_encode_unsigned_integer (buf, 1, &length); checkerr;
    sum += length;
    ret = asn1_make_etag(buf, CONTEXT_SPECIFIC, 0, length, &length); checkerr;
    sum += length;

    ret = asn1_make_sequence(buf, sum, &length); checkerr;
    sum += length;

    /* The reverse encoding is straightened out here */
    ret = asn12krb5_buf (buf, code); checkerr;

last:
    asn1buf_destroy (&buf);

    if (ret != 0 && *code != NULL) {
        if ((*code)->data != NULL)
            free ((*code)->data);
        free (*code);
    }

    return ret;
}

/************************************************************************/
/* Decode the Principal's keys						*/
/************************************************************************/

#define safe_syncbuf(outer,inner)					\
	if (! ((inner)->next == (inner)->bound + 1 &&			\
	       (inner)->next == (outer)->next + buflen))		\
	    cleanup (ASN1_BAD_LENGTH);					\
	asn1buf_sync((outer), (inner), 0, 0, 0, 0, 0);

static asn1_error_code
decode_tagged_integer (asn1buf *buf, asn1_tagnum expectedtag, long *val)
{
    int buflen;
    asn1_error_code ret = 0;
    asn1buf tmp, subbuf;
    taginfo t;

    /* Work on a copy of 'buf' */
    ret = asn1buf_imbed(&tmp, buf, 0, 1); checkerr;
    ret = asn1_get_tag_2(&tmp, &t); checkerr;
    if (t.tagnum != expectedtag)
	cleanup (ASN1_MISSING_FIELD);

    buflen = t.length;
    ret = asn1buf_imbed(&subbuf, &tmp, t.length, 0); checkerr;
    ret = asn1_decode_integer(&subbuf, val); checkerr;

    safe_syncbuf(&tmp, &subbuf);
    *buf = tmp;

last:
    return ret;
}

#if 0 /* not currently used */
static asn1_error_code
decode_tagged_unsigned_integer (asn1buf *buf, int expectedtag, unsigned long *val)
{
    int buflen;
    asn1_error_code ret = 0;
    asn1buf tmp, subbuf;
    taginfo t;

    /* Work on a copy of 'buf' */
    ret = asn1buf_imbed(&tmp, buf, 0, 1); checkerr;
    ret = asn1_get_tag_2(&tmp, &t); checkerr;
    if (t.tagnum != expectedtag)
	cleanup (ASN1_MISSING_FIELD);

    buflen = t.length;
    ret = asn1buf_imbed(&subbuf, &tmp, t.length, 0); checkerr;
    ret = asn1_decode_unsigned_integer(&subbuf, val); checkerr;

    safe_syncbuf(&tmp, &subbuf);
    *buf = tmp;

last:
    return ret;
}
#endif

static asn1_error_code
decode_tagged_octetstring (asn1buf *buf, asn1_tagnum expectedtag, int *len,
			   asn1_octet **val)
{
    int buflen;
    asn1_error_code ret = 0;
    asn1buf tmp, subbuf;
    taginfo t;

    *val = NULL;

    /* Work on a copy of 'buf' */
    ret = asn1buf_imbed(&tmp, buf, 0, 1); checkerr;
    ret = asn1_get_tag_2(&tmp, &t); checkerr;
    if (t.tagnum != expectedtag)
	cleanup (ASN1_MISSING_FIELD);

    buflen = t.length;
    ret = asn1buf_imbed(&subbuf, &tmp, t.length, 0); checkerr;
    ret = asn1_decode_octetstring (&subbuf, len, val); checkerr;

    safe_syncbuf(&tmp, &subbuf);
    *buf = tmp;

last:
    if (ret != 0 && *val != NULL)
	free (*val);
    return ret;
}

static asn1_error_code asn1_decode_key(asn1buf *buf, krb5_key_data *key)
{
    int buflen, seqindef;
    unsigned int length;
    asn1_error_code ret;
    asn1buf subbuf;
    taginfo t;

    key->key_data_contents[0] = NULL;
    key->key_data_contents[1] = NULL;

    ret = asn1_get_sequence(buf, &length, &seqindef); checkerr;
    buflen = length;
    ret = asn1buf_imbed(&subbuf, buf, length, seqindef); checkerr;

    asn1_get_tag_2(&subbuf, &t);
    /* Salt */
    if (t.tagnum == 0) {
	int buflen;
	asn1buf slt;
	unsigned long keytype;
	int keylen;

	key->key_data_ver = 2;
	asn1_get_sequence(&subbuf, &length, &seqindef);
	buflen = length;
	asn1buf_imbed(&slt, &subbuf, length, seqindef);

	ret = decode_tagged_integer (&slt, 0, &keytype);
	key->key_data_type[1] = keytype; /* XXX range check?? */
	checkerr;

	if (asn1buf_remains(&slt, 0) != 0) { /* Salt value is optional */
	    ret = decode_tagged_octetstring (&slt, 1, &keylen,
		    &key->key_data_contents[1]); checkerr;
	}
	safe_syncbuf (&subbuf, &slt);
	key->key_data_length[1] = keylen; /* XXX range check?? */

	ret = asn1_get_tag_2(&subbuf, &t); checkerr;
    } else
	key->key_data_ver = 1;

    /* Key */
    {
	int buflen;
	asn1buf kbuf;
	long lval;
	int ival;

	if (t.tagnum != 1)
	    cleanup (ASN1_MISSING_FIELD);

	ret = asn1_get_sequence(&subbuf, &length, &seqindef); checkerr;
	buflen = length;
	ret = asn1buf_imbed(&kbuf, &subbuf, length, seqindef); checkerr;

	ret = decode_tagged_integer (&kbuf, 0, &lval);
	checkerr;
	key->key_data_type[0] = lval; /* XXX range check? */

	ret = decode_tagged_octetstring (&kbuf, 1, &ival,
					 &key->key_data_contents[0]); checkerr;
	key->key_data_length[0] = ival;	/* XXX range check? */

	safe_syncbuf (&subbuf, &kbuf);
    }

    safe_syncbuf (buf, &subbuf);

last:
    if (ret != 0) {
	if (key->key_data_contents[0] != NULL) {
	    free (key->key_data_contents[0]);
	    key->key_data_contents[0] = NULL;
	}
	if (key->key_data_contents[1] != NULL) {
	    free (key->key_data_contents[1]);
	    key->key_data_contents[1] = NULL;
	}
    }
    return ret;
}

/* asn1_error_code asn1_decode_sequence_of_keys (krb5_data *in, */
krb5_error_code asn1_decode_sequence_of_keys (krb5_data *in,
					      krb5_key_data **out,
					      krb5_int16 *n_key_data,
					      int *mkvno)
{
    asn1_error_code ret;
    asn1buf buf, subbuf;
    int seqindef;
    unsigned int length;
    taginfo t;
    int kvno, maj, min;
    long lval;

    *n_key_data = 0;
    *out = NULL;

    ret = asn1buf_wrap_data(&buf, in); checkerr;

    ret = asn1_get_sequence(&buf, &length, &seqindef); checkerr;
    ret = asn1buf_imbed(&subbuf, &buf, length, seqindef); checkerr;

    /* attribute-major-vno */
    ret = decode_tagged_integer (&subbuf, 0, &lval); checkerr;
    maj = lval;			/* XXX range check? */

    /* attribute-minor-vno */
    ret = decode_tagged_integer (&subbuf, 1, &lval); checkerr;
    min = lval;			/* XXX range check? */

    if (maj != 1 || min != 1)
	cleanup (ASN1_BAD_FORMAT);

    /* kvno (assuming all keys in array have same version) */
    ret = decode_tagged_integer (&subbuf, 2, &lval); checkerr;
    kvno = lval;		/* XXX range check? */

    /* mkvno (optional) */
    ret = decode_tagged_integer (&subbuf, 3, &lval); checkerr;
    *mkvno = lval;		/* XXX range check? */

    ret = asn1_get_tag_2(&subbuf, &t); checkerr;

    /* Sequence of keys */
    {
	int i, buflen;
	asn1buf keyseq;
	if (t.tagnum != 4)
	    cleanup (ASN1_MISSING_FIELD);
	ret = asn1_get_sequence(&subbuf, &length, &seqindef); checkerr;
	buflen = length;
	ret = asn1buf_imbed(&keyseq, &subbuf, length, seqindef); checkerr;
	for (i = 1, *out = NULL; ; i++) {
	    krb5_key_data *tmp;
	    tmp = (krb5_key_data *) realloc (*out, i * sizeof (krb5_key_data));
	    if (tmp == NULL)
		cleanup (ENOMEM);
	    *out = tmp;
	    (*out)[i - 1].key_data_kvno = kvno;
	    ret = asn1_decode_key(&keyseq, &(*out)[i - 1]); checkerr;
	    (*n_key_data)++;
	    if (asn1buf_remains(&keyseq, 0) == 0)
		break; /* Not freeing the last key structure */
	}
	safe_syncbuf (&subbuf, &keyseq);
    }

    /*
     * There could be other data inside the outermost sequence ... tags we don't
     * know about. So, not invoking "safe_syncbuf(&buf,&subbuf)"
     */

last:
    if (ret != 0) {
	int i;
	for (i = 0; i < *n_key_data; i++) {
	    if ((*out)[i].key_data_contents[0] != NULL)
		free ((*out)[i].key_data_contents[0]);
	    if ((*out)[i].key_data_contents[1] != NULL)
		free ((*out)[i].key_data_contents[1]);
	}
	free (*out);
	*out = NULL;
    }

    return ret;
}