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NetBSD/lib/libresolv/dst_api.c

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/* $NetBSD: dst_api.c,v 1.11 2024/02/05 21:46:05 andvar Exp $ */
/*
* Portions Copyright (c) 1995-1998 by Trusted Information Systems, Inc.
*
* Permission to use, copy modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND TRUSTED INFORMATION SYSTEMS
* DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
* TRUSTED INFORMATION SYSTEMS BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE USE OR PERFORMANCE OF THE SOFTWARE.
*/
/*
* This file contains the interface between the DST API and the crypto API.
* This is the only file that needs to be changed if the crypto system is
* changed. Exported functions are:
* void dst_init() Initialize the toolkit
* int dst_check_algorithm() Function to determines if alg is supported.
* int dst_compare_keys() Function to compare two keys for equality.
* int dst_sign_data() Incremental signing routine.
* int dst_verify_data() Incremental verify routine.
* int dst_generate_key() Function to generate new KEY
* DST_KEY *dst_read_key() Function to retrieve private/public KEY.
* void dst_write_key() Function to write out a key.
* DST_KEY *dst_dnskey_to_key() Function to convert DNS KEY RR to a DST
* KEY structure.
* int dst_key_to_dnskey() Function to return a public key in DNS
* format binary
* DST_KEY *dst_buffer_to_key() Converst a data in buffer to KEY
* int *dst_key_to_buffer() Writes out DST_KEY key matterial in buffer
* void dst_free_key() Releases all memory referenced by key structure
*/
#include <sys/cdefs.h>
#if 0
static const char rcsid[] = "Header: /proj/cvs/prod/libbind/dst/dst_api.c,v 1.17 2007/09/24 17:18:25 each Exp ";
#else
__RCSID("$NetBSD: dst_api.c,v 1.11 2024/02/05 21:46:05 andvar Exp $");
#endif
#include "port_before.h"
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <memory.h>
#include <ctype.h>
#include <time.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include "dst_internal.h"
#include "port_after.h"
/* static variables */
static int done_init = 0;
dst_func *dst_t_func[DST_MAX_ALGS];
const char *dst_path = "";
/* internal I/O functions */
static DST_KEY *dst_s_read_public_key(const char *in_name,
const u_int16_t in_id, int in_alg);
static int dst_s_read_private_key_file(char *name, DST_KEY *pk_key,
u_int16_t in_id, int in_alg);
static int dst_s_write_public_key(const DST_KEY *key);
static int dst_s_write_private_key(const DST_KEY *key);
/* internal function to set up data structure */
static DST_KEY *dst_s_get_key_struct(const char *name, const int alg,
const int flags, const int protocol,
const int bits);
/*%
* dst_init
* This function initializes the Digital Signature Toolkit.
* Right now, it just checks the DSTKEYPATH environment variable.
* Parameters
* none
* Returns
* none
*/
void
dst_init(void)
{
char *s;
size_t len;
if (done_init != 0)
return;
done_init = 1;
s = getenv("DSTKEYPATH");
len = 0;
if (s) {
struct stat statbuf;
len = strlen(s);
if (len > PATH_MAX) {
EREPORT(("%s: %s is longer than %d characters,"
" ignoring\n", __func__, s, PATH_MAX));
} else if (stat(s, &statbuf) != 0 ||
!S_ISDIR(statbuf.st_mode)) {
EREPORT(("%s: %s is not a valid directory\n",
__func__, s));
} else {
char *tmp;
tmp = (char *) malloc(len + 2);
memcpy(tmp, s, len + 1);
if (tmp[strlen(tmp) - 1] != '/') {
tmp[strlen(tmp) + 1] = 0;
tmp[strlen(tmp)] = '/';
}
dst_path = tmp;
}
}
memset(dst_t_func, 0, sizeof(dst_t_func));
/* first one is selected */
dst_hmac_md5_init();
}
/*%
* dst_check_algorithm
* This function determines if the crypto system for the specified
* algorithm is present.
* Parameters
* alg 1 KEY_RSA
* 3 KEY_DSA
* 157 KEY_HMAC_MD5
* future algorithms TBD and registered with IANA.
* Returns
* 1 - The algorithm is available.
* 0 - The algorithm is not available.
*/
int
dst_check_algorithm(const int alg)
{
return (dst_t_func[alg] != NULL);
}
/*%
* dst_s_get_key_struct
* This function allocates key structure and fills in some of the
* fields of the structure.
* Parameters:
* name: the name of the key
* alg: the algorithm number
* flags: the dns flags of the key
* protocol: the dns protocol of the key
* bits: the size of the key
* Returns:
* NULL if error
* valid pointer otherwise
*/
static DST_KEY *
dst_s_get_key_struct(const char *name, const int alg, const int flags,
const int protocol, const int bits)
{
DST_KEY *new_key = NULL;
if (dst_check_algorithm(alg)) /*%< make sure alg is available */
new_key = (DST_KEY *) malloc(sizeof(*new_key));
if (new_key == NULL)
return (NULL);
memset(new_key, 0, sizeof(*new_key));
new_key->dk_key_name = strdup(name);
if (new_key->dk_key_name == NULL) {
free(new_key);
return (NULL);
}
new_key->dk_alg = alg;
new_key->dk_flags = flags;
new_key->dk_proto = protocol;
new_key->dk_KEY_struct = NULL;
new_key->dk_key_size = bits;
new_key->dk_func = dst_t_func[alg];
return (new_key);
}
/*%
* dst_compare_keys
* Compares two keys for equality.
* Parameters
* key1, key2 Two keys to be compared.
* Returns
* 0 The keys are equal.
* non-zero The keys are not equal.
*/
int
dst_compare_keys(const DST_KEY *key1, const DST_KEY *key2)
{
if (key1 == key2)
return (0);
if (key1 == NULL || key2 == NULL)
return (4);
if (key1->dk_alg != key2->dk_alg)
return (1);
if (key1->dk_key_size != key2->dk_key_size)
return (2);
if (key1->dk_id != key2->dk_id)
return (3);
return (key1->dk_func->compare(key1, key2));
}
/*%
* dst_sign_data
* An incremental signing function. Data is signed in steps.
* First the context must be initialized (SIG_MODE_INIT).
* Then data is hashed (SIG_MODE_UPDATE). Finally the signature
* itself is created (SIG_MODE_FINAL). This function can be called
* once with INIT, UPDATE and FINAL modes all set, or it can be
* called separately with a different mode set for each step. The
* UPDATE step can be repeated.
* Parameters
* mode A bit mask used to specify operation(s) to be performed.
* SIG_MODE_INIT 1 Initialize digest
* SIG_MODE_UPDATE 2 Add data to digest
* SIG_MODE_FINAL 4 Generate signature
* from signature
* SIG_MODE_ALL (SIG_MODE_INIT,SIG_MODE_UPDATE,SIG_MODE_FINAL
* data Data to be signed.
* len The length in bytes of data to be signed.
* in_key Contains a private key to sign with.
* KEY structures should be handled (created, converted,
* compared, stored, freed) by the DST.
* signature
* The location to which the signature will be written.
* sig_len Length of the signature field in bytes.
* Return
* 0 Successful INIT or Update operation
* &gt;0 success FINAL (sign) operation
* &lt;0 failure
*/
int
dst_sign_data(const int mode, DST_KEY *in_key, void **context,
const u_char *data, const int len,
u_char *signature, const int sig_len)
{
DUMP(data, mode, len, "dst_sign_data()");
if (mode & SIG_MODE_FINAL &&
(in_key->dk_KEY_struct == NULL || signature == NULL))
return (MISSING_KEY_OR_SIGNATURE);
if (in_key->dk_func && in_key->dk_func->sign)
return (in_key->dk_func->sign(mode, in_key, context, data, len,
signature, sig_len));
return (UNKNOWN_KEYALG);
}
/*%
* dst_verify_data
* An incremental verify function. Data is verified in steps.
* First the context must be initialized (SIG_MODE_INIT).
* Then data is hashed (SIG_MODE_UPDATE). Finally the signature
* is verified (SIG_MODE_FINAL). This function can be called
* once with INIT, UPDATE and FINAL modes all set, or it can be
* called separately with a different mode set for each step. The
* UPDATE step can be repeated.
* Parameters
* mode Operations to perform this time.
* SIG_MODE_INIT 1 Initialize digest
* SIG_MODE_UPDATE 2 add data to digest
* SIG_MODE_FINAL 4 verify signature
* SIG_MODE_ALL
* (SIG_MODE_INIT,SIG_MODE_UPDATE,SIG_MODE_FINAL)
* data Data to pass through the hash function.
* len Length of the data in bytes.
* in_key Key for verification.
* signature Location of signature.
* sig_len Length of the signature in bytes.
* Returns
* 0 Verify success
* Non-Zero Verify Failure
*/
int
dst_verify_data(const int mode, DST_KEY *in_key, void **context,
const u_char *data, const int len,
const u_char *signature, const int sig_len)
{
DUMP(data, mode, len, "dst_verify_data()");
if (mode & SIG_MODE_FINAL &&
(in_key->dk_KEY_struct == NULL || signature == NULL))
return (MISSING_KEY_OR_SIGNATURE);
if (in_key->dk_func == NULL || in_key->dk_func->verify == NULL)
return (UNSUPPORTED_KEYALG);
return (in_key->dk_func->verify(mode, in_key, context, data, len,
signature, sig_len));
}
/*%
* dst_read_private_key
* Access a private key. First the list of private keys that have
* already been read in is searched, then the key accessed on disk.
* If the private key can be found, it is returned. If the key cannot
* be found, a null pointer is returned. The options specify required
* key characteristics. If the private key requested does not have
* these characteristics, it will not be read.
* Parameters
* in_keyname The private key name.
* in_id The id of the private key.
* options DST_FORCE_READ Read from disk - don't use a previously
* read key.
* DST_CAN_SIGN The key must be useable for signing.
* DST_NO_AUTHEN The key must be useable for authentication.
* DST_STANDARD Return any key
* Returns
* NULL If there is no key found in the current directory or
* this key has not been loaded before.
* !NULL Success - KEY structure returned.
*/
DST_KEY *
dst_read_key(const char *in_keyname, const u_int16_t in_id,
const int in_alg, const int type)
{
char keyname[PATH_MAX];
DST_KEY *dg_key = NULL, *pubkey = NULL;
if (!dst_check_algorithm(in_alg)) { /*%< make sure alg is available */
EREPORT(("%s: Algorithm %d not supported\n", __func__, in_alg));
return (NULL);
}
if ((type & (DST_PUBLIC | DST_PRIVATE)) == 0)
return (NULL);
if (in_keyname == NULL) {
EREPORT(("%s: Null key name passed in\n", __func__));
return (NULL);
} else if (strlen(in_keyname) >= sizeof(keyname)) {
EREPORT(("%s: keyname too big\n", __func__));
return (NULL);
} else
strcpy(keyname, in_keyname);
/* before I read in the public key, check if it is allowed to sign */
if ((pubkey = dst_s_read_public_key(keyname, in_id, in_alg)) == NULL)
return (NULL);
if (type == DST_PUBLIC)
return pubkey;
if (!(dg_key = dst_s_get_key_struct(keyname, pubkey->dk_alg,
(int)pubkey->dk_flags,
pubkey->dk_proto, 0)))
return (dg_key);
/* Fill in private key and some fields in the general key structure */
if (dst_s_read_private_key_file(keyname, dg_key, pubkey->dk_id,
pubkey->dk_alg) == 0)
dg_key = dst_free_key(dg_key);
(void)dst_free_key(pubkey);
return (dg_key);
}
int
dst_write_key(const DST_KEY *key, const int type)
{
int pub = 0, priv = 0;
if (key == NULL)
return (0);
if (!dst_check_algorithm(key->dk_alg)) { /*%< make sure alg is available */
EREPORT(("%s: Algorithm %d not supported\n", __func__,
key->dk_alg));
return (UNSUPPORTED_KEYALG);
}
if ((type & (DST_PRIVATE|DST_PUBLIC)) == 0)
return (0);
if (type & DST_PUBLIC)
if ((pub = dst_s_write_public_key(key)) < 0)
return (pub);
if (type & DST_PRIVATE)
if ((priv = dst_s_write_private_key(key)) < 0)
return (priv);
return (priv+pub);
}
/*%
* dst_write_private_key
* Write a private key to disk. The filename will be of the form:
* K&lt;key-&gt;dk_name&gt;+&lt;key-&gt;dk_alg+&gt;&lt;key-d&gt;k_id.&gt;&lt;private key suffix&gt;.
* If there is already a file with this name, an error is returned.
*
* Parameters
* key A DST managed key structure that contains
* all information needed about a key.
* Return
* &gt;= 0 Correct behavior. Returns length of encoded key value
* written to disk.
* &lt; 0 error.
*/
static int
dst_s_write_private_key(const DST_KEY *key)
{
u_char encoded_block[RAW_KEY_SIZE];
char file[PATH_MAX];
int len;
FILE *fp;
/* First encode the key into the portable key format */
if (key == NULL)
return (-1);
if (key->dk_KEY_struct == NULL)
return (0); /*%< null key has no private key */
if (key->dk_func == NULL || key->dk_func->to_file_fmt == NULL) {
EREPORT(("%s: Unsupported operation %d\n", __func__,
key->dk_alg));
return (-5);
} else if ((len = key->dk_func->to_file_fmt(key, (char *)encoded_block,
(int)sizeof(encoded_block))) <= 0) {
EREPORT(("%s: Failed encoding private RSA bsafe key %d\n",
__func__, len));
return (-8);
}
/* Now I can create the file I want to use */
dst_s_build_filename(file, key->dk_key_name, key->dk_id, key->dk_alg,
PRIVATE_KEY, PATH_MAX);
/* Do not overwrite an existing file */
if ((fp = dst_s_fopen(file, "w", 0600)) != NULL) {
ssize_t nn;
nn = fwrite(encoded_block, 1, len, fp);
if (nn != len) {
EREPORT(("%s: Write failure on %s %d != %zd"
" errno=%d\n", __func__, file, len, nn, errno));
fclose(fp);
return (-5);
}
fclose(fp);
} else {
EREPORT(("%s: Can not create file %s\n", __func__,
file));
return (-6);
}
memset(encoded_block, 0, len);
return (len);
}
/*%
*
* dst_read_public_key
* Read a public key from disk and store in a DST key structure.
* Parameters
* in_name K&lt;in_name&gt;&lt;in_id&gt;.&lt;public key suffix&gt; is the
* filename of the key file to be read.
* Returns
* NULL If the key does not exist or no name is supplied.
* NON-NULL Initialized key structure if the key exists.
*/
static DST_KEY *
dst_s_read_public_key(const char *in_name, const u_int16_t in_id, int in_alg)
{
int flags, proto, alg, dlen;
size_t len;
int c;
char name[PATH_MAX], enckey[RAW_KEY_SIZE], *notspace;
u_char deckey[RAW_KEY_SIZE];
FILE *fp;
if (in_name == NULL) {
EREPORT(("%s: No key name given\n", __func__));
return (NULL);
}
if (dst_s_build_filename(name, in_name, in_id, in_alg, PUBLIC_KEY,
PATH_MAX) == -1) {
EREPORT(("%s: Cannot make filename from %s, %d, and %s\n",
__func__, in_name, in_id, PUBLIC_KEY));
return (NULL);
}
/*
* Open the file and read it's formatted contents up to key
* File format:
* domain.name [ttl] [IN] KEY &lt;flags&gt; &lt;protocol&gt; &lt;algorithm&gt; &lt;key&gt;
* flags, proto, alg stored as decimal (or hex numbers FIXME).
* (FIXME: handle parentheses for line continuation.)
*/
if ((fp = dst_s_fopen(name, "r", 0)) == NULL) {
EREPORT(("%s: Public Key not found %s\n", __func__, name));
return (NULL);
}
/* Skip domain name, which ends at first blank */
while ((c = getc(fp)) != EOF)
if (isspace(c))
break;
/* Skip blank to get to next field */
while ((c = getc(fp)) != EOF)
if (!isspace(c))
break;
/* Skip optional TTL -- if initial digit, skip whole word. */
if (isdigit(c)) {
while ((c = getc(fp)) != EOF)
if (isspace(c))
break;
while ((c = getc(fp)) != EOF)
if (!isspace(c))
break;
}
/* Skip optional "IN" */
if (c == 'I' || c == 'i') {
while ((c = getc(fp)) != EOF)
if (isspace(c))
break;
while ((c = getc(fp)) != EOF)
if (!isspace(c))
break;
}
/* Locate and skip "KEY" */
if (c != 'K' && c != 'k') {
EREPORT(("%s: \"KEY\" doesn't appear in file: %s", __func__,
name));
return NULL;
}
while ((c = getc(fp)) != EOF)
if (isspace(c))
break;
while ((c = getc(fp)) != EOF)
if (!isspace(c))
break;
ungetc(c, fp); /*%< return the character to the input field */
/* Handle hex!! FIXME. */
if (fscanf(fp, "%d %d %d", &flags, &proto, &alg) != 3) {
EREPORT(("%s: Can not read flag/proto/alg field from %s\n",
__func__, name));
return (NULL);
}
/* read in the key string */
fgets(enckey, (int)sizeof(enckey), fp);
/* If we aren't at end-of-file, something is wrong. */
while ((c = getc(fp)) != EOF)
if (!isspace(c))
break;
if (!feof(fp)) {
EREPORT(("%s: Key too long in file: %s", __func__, name));
return NULL;
}
fclose(fp);
if ((len = strlen(enckey)) == 0)
return (NULL);
/* discard \n */
enckey[--len] = '\0';
/* remove leading spaces */
for (notspace = (char *) enckey; isspace((*notspace)&0xff); len--)
notspace++;
dlen = b64_pton(notspace, deckey, sizeof(deckey));
if (dlen < 0) {
EREPORT(("%s: bad return from b64_pton = %d", __func__, dlen));
return (NULL);
}
/* store key and info in a key structure that is returned */
/* return dst_store_public_key(in_name, alg, proto, 666, flags, deckey,
dlen);*/
return dst_buffer_to_key(in_name, alg, flags, proto, deckey, dlen);
}
/*%
* dst_write_public_key
* Write a key to disk in DNS format.
* Parameters
* key Pointer to a DST key structure.
* Returns
* 0 Failure
* 1 Success
*/
static int
dst_s_write_public_key(const DST_KEY *key)
{
FILE *fp;
char filename[PATH_MAX];
u_char out_key[RAW_KEY_SIZE];
char enc_key[RAW_KEY_SIZE];
int len = 0;
int mode;
memset(out_key, 0, sizeof(out_key));
if (key == NULL) {
EREPORT(("%s: No key specified \n", __func__));
return (0);
} else if ((len = dst_key_to_dnskey(key, out_key,
(int)sizeof(out_key)))< 0)
return (0);
/* Make the filename */
if (dst_s_build_filename(filename, key->dk_key_name, key->dk_id,
key->dk_alg, PUBLIC_KEY, PATH_MAX) == -1) {
EREPORT(("%s: Cannot make filename from %s, %d, and %s\n",
__func__, key->dk_key_name, key->dk_id, PUBLIC_KEY));
return (0);
}
/* XXX in general this should be a check for symmetric keys */
mode = (key->dk_alg == KEY_HMAC_MD5) ? 0600 : 0644;
/* create public key file */
if ((fp = dst_s_fopen(filename, "w+", mode)) == NULL) {
EREPORT(("%s: open of file:%s failed (errno=%d)\n",
__func__, filename, errno));
return (0);
}
/*write out key first base64 the key data */
if (key->dk_flags & DST_EXTEND_FLAG)
b64_ntop(&out_key[6], len - 6, enc_key, sizeof(enc_key));
else
b64_ntop(&out_key[4], len - 4, enc_key, sizeof(enc_key));
fprintf(fp, "%s IN KEY %d %d %d %s\n",
key->dk_key_name,
key->dk_flags, key->dk_proto, key->dk_alg, enc_key);
fclose(fp);
return (1);
}
/*%
* dst_dnskey_to_public_key
* This function converts the contents of a DNS KEY RR into a DST
* key structure.
* Parameters
* len Length of the RDATA of the KEY RR RDATA
* rdata A pointer to the KEY RR RDATA.
* in_name Key name to be stored in key structure.
* Returns
* NULL Failure
* NON-NULL Success. Pointer to key structure.
* Caller's responsibility to free() it.
*/
DST_KEY *
dst_dnskey_to_key(const char *in_name, const u_char *rdata, const int len)
{
DST_KEY *key_st;
int alg ;
int start = DST_KEY_START;
if (rdata == NULL || len <= DST_KEY_ALG) /*%< no data */
return (NULL);
alg = (u_int8_t) rdata[DST_KEY_ALG];
if (!dst_check_algorithm(alg)) { /*%< make sure alg is available */
EREPORT(("%s: Algorithm %d not supported\n", __func__,
alg));
return (NULL);
}
if (in_name == NULL)
return (NULL);
if ((key_st = dst_s_get_key_struct(in_name, alg, 0, 0, 0)) == NULL)
return (NULL);
key_st->dk_id = dst_s_dns_key_id(rdata, len);
key_st->dk_flags = dst_s_get_int16(rdata);
key_st->dk_proto = (u_int16_t) rdata[DST_KEY_PROT];
if (key_st->dk_flags & DST_EXTEND_FLAG) {
u_int32_t ext_flags;
ext_flags = (u_int32_t) dst_s_get_int16(&rdata[DST_EXT_FLAG]);
key_st->dk_flags = key_st->dk_flags | (ext_flags << 16);
start += 2;
}
/*
* now point to the beginning of the data representing the encoding
* of the key
*/
if (key_st->dk_func && key_st->dk_func->from_dns_key) {
if (key_st->dk_func->from_dns_key(key_st, &rdata[start],
len - start) > 0)
return (key_st);
} else
EREPORT(("%s: unsupported alg %d\n", __func__,
alg));
SAFE_FREE(key_st);
return (NULL);
}
/*%
* dst_public_key_to_dnskey
* Function to encode a public key into DNS KEY wire format
* Parameters
* key Key structure to encode.
* out_storage Location to write the encoded key to.
* out_len Size of the output array.
* Returns
* <0 Failure
* >=0 Number of bytes written to out_storage
*/
int
dst_key_to_dnskey(const DST_KEY *key, u_char *out_storage,
const int out_len)
{
u_int16_t val;
int loc = 0;
int enc_len = 0;
if (key == NULL)
return (-1);
if (!dst_check_algorithm(key->dk_alg)) { /*%< make sure alg is available */
EREPORT(("%s: Algorithm %d not supported\n", __func__,
key->dk_alg));
return (UNSUPPORTED_KEYALG);
}
memset(out_storage, 0, out_len);
val = (u_int16_t)(key->dk_flags & 0xffff);
dst_s_put_int16(out_storage, val);
loc += 2;
out_storage[loc++] = (u_char) key->dk_proto;
out_storage[loc++] = (u_char) key->dk_alg;
if (key->dk_flags > 0xffff) { /*%< Extended flags */
val = (u_int16_t)((key->dk_flags >> 16) & 0xffff);
dst_s_put_int16(&out_storage[loc], val);
loc += 2;
}
if (key->dk_KEY_struct == NULL)
return (loc);
if (key->dk_func && key->dk_func->to_dns_key) {
enc_len = key->dk_func->to_dns_key(key,
(u_char *) &out_storage[loc],
out_len - loc);
if (enc_len > 0)
return (enc_len + loc);
else
return (-1);
} else
EREPORT(("%s: Unsupported ALG %d\n", __func__, key->dk_alg));
return (-1);
}
/*%
* dst_buffer_to_key
* Function to encode a string of raw data into a DST key
* Parameters
* alg The algorithm (HMAC only)
* key A pointer to the data
* keylen The length of the data
* Returns
* NULL an error occurred
* NON-NULL the DST key
*/
DST_KEY *
dst_buffer_to_key(const char *key_name, /*!< name of the key */
const int alg, /*!< algorithm */
const int flags, /*!< dns flags */
const int protocol, /*!< dns protocol */
const u_char *key_buf, /*!< key in dns wire fmt */
const int key_len) /*!< size of key */
{
DST_KEY *dkey = NULL;
int dnslen;
u_char dns[2048];
if (!dst_check_algorithm(alg)) { /*%< make sure alg is available */
EREPORT(("%s: Algorithm %d not supported\n", __func__, alg));
return (NULL);
}
dkey = dst_s_get_key_struct(key_name, alg, flags, protocol, -1);
if (dkey == NULL || dkey->dk_func == NULL ||
dkey->dk_func->from_dns_key == NULL)
return (dst_free_key(dkey));
if (dkey->dk_func->from_dns_key(dkey, key_buf, key_len) < 0) {
EREPORT(("%s: dst_buffer_to_hmac failed\n", __func__));
return (dst_free_key(dkey));
}
dnslen = dst_key_to_dnskey(dkey, dns, (int)sizeof(dns));
dkey->dk_id = dst_s_dns_key_id(dns, dnslen);
return (dkey);
}
int
dst_key_to_buffer(DST_KEY *key, u_char *out_buff, int buf_len)
{
int len;
/* this function will extrac the secret of HMAC into a buffer */
if (key == NULL)
return (0);
if (key->dk_func != NULL && key->dk_func->to_dns_key != NULL) {
len = key->dk_func->to_dns_key(key, out_buff, buf_len);
if (len < 0)
return (0);
return (len);
}
return (0);
}
/*%
* dst_s_read_private_key_file
* Function reads in private key from a file.
* Fills out the KEY structure.
* Parameters
* name Name of the key to be read.
* pk_key Structure that the key is returned in.
* in_id Key identifier (tag)
* Return
* 1 if everything works
* 0 if there is any problem
*/
static int
dst_s_read_private_key_file(char *name, DST_KEY *pk_key, u_int16_t in_id,
int in_alg)
{
int alg, major, minor, file_major, file_minor;
ssize_t cnt;
size_t len;
int ret, id;
char filename[PATH_MAX];
u_char in_buff[RAW_KEY_SIZE], *p;
FILE *fp;
int dnslen;
u_char dns[2048];
if (name == NULL || pk_key == NULL) {
EREPORT(("%s: No key name given\n", __func__));
return (0);
}
/* Make the filename */
if (dst_s_build_filename(filename, name, in_id, in_alg, PRIVATE_KEY,
PATH_MAX) == -1) {
EREPORT(("%s: Cannot make filename from %s, %d, and %s\n",
__func__, name, in_id, PRIVATE_KEY));
return (0);
}
/* first check if we can find the key file */
if ((fp = dst_s_fopen(filename, "r", 0)) == NULL) {
EREPORT(("%s: Could not open file %s in directory %s\n",
__func__, filename, dst_path[0] ? dst_path :
getcwd(NULL, PATH_MAX - 1)));
return (0);
}
/* now read the header info from the file */
if ((cnt = fread(in_buff, 1, sizeof(in_buff), fp)) < 5) {
fclose(fp);
EREPORT(("%s: error reading file %s (empty file)\n",
__func__, filename));
return (0);
}
len = cnt;
/* decrypt key */
fclose(fp);
if (memcmp(in_buff, "Private-key-format: v", 20) != 0)
goto fail;
p = in_buff;
if (!dst_s_verify_str((const char **) (void *)&p,
"Private-key-format: v")) {
EREPORT(("%s: Not a Key file/Decrypt failed %s\n", __func__,
name));
goto fail;
}
/* read in file format */
sscanf((char *)p, "%d.%d", &file_major, &file_minor);
sscanf(KEY_FILE_FORMAT, "%d.%d", &major, &minor);
if (file_major < 1) {
EREPORT(("%s: Unknown keyfile %d.%d version for %s\n",
__func__, file_major, file_minor, name));
goto fail;
} else if (file_major > major || file_minor > minor)
EREPORT(("%s: Keyfile %s version higher than mine %d.%d MAY"
" FAIL\n", __func__, name, file_major, file_minor));
while (*p++ != '\n') ; /*%< skip to end of line */
if (!dst_s_verify_str((const char **) (void *)&p, "Algorithm: "))
goto fail;
if (sscanf((char *)p, "%d", &alg) != 1)
goto fail;
while (*p++ != '\n') ; /*%< skip to end of line */
if (pk_key->dk_key_name && !strcmp(pk_key->dk_key_name, name))
SAFE_FREE2(pk_key->dk_key_name, strlen(pk_key->dk_key_name));
pk_key->dk_key_name = strdup(name);
/* allocate and fill in key structure */
if (pk_key->dk_func == NULL || pk_key->dk_func->from_file_fmt == NULL)
goto fail;
ret = pk_key->dk_func->from_file_fmt(pk_key, (char *)p,
(int)(&in_buff[len] - p));
if (ret < 0)
goto fail;
dnslen = dst_key_to_dnskey(pk_key, dns, (int)sizeof(dns));
id = dst_s_dns_key_id(dns, dnslen);
/* Make sure the actual key tag matches the input tag used in the
* filename */
if (id != in_id) {
EREPORT(("%s: actual tag of key read %d != input tag used to"
"build filename %d.\n", __func__, id, in_id));
goto fail;
}
pk_key->dk_id = (u_int16_t) id;
pk_key->dk_alg = alg;
memset(in_buff, 0, len);
return (1);
fail:
memset(in_buff, 0, len);
return (0);
}
/*%
* Generate and store a public/private keypair.
* Keys will be stored in formatted files.
*
* Parameters
&
*\par name Name of the new key. Used to create key files
*\li K&lt;name&gt;+&lt;alg&gt;+&lt;id&gt;.public and K&lt;name&gt;+&lt;alg&gt;+&lt;id&gt;.private.
*\par bits Size of the new key in bits.
*\par exp What exponent to use:
*\li 0 use exponent 3
*\li non-zero use Fermant4
*\par flags The default value of the DNS Key flags.
*\li The DNS Key RR Flag field is defined in RFC2065,
* section 3.3. The field has 16 bits.
*\par protocol
*\li Default value of the DNS Key protocol field.
*\li The DNS Key protocol field is defined in RFC2065,
* section 3.4. The field has 8 bits.
*\par alg What algorithm to use. Currently defined:
*\li KEY_RSA 1
*\li KEY_DSA 3
*\li KEY_HMAC 157
*\par out_id The key tag is returned.
*
* Return
*\li NULL Failure
*\li non-NULL the generated key pair
* Caller frees the result, and its dk_name pointer.
*/
DST_KEY *
dst_generate_key(const char *name, const int bits, const int exp,
const int flags, const int protocol, const int alg)
{
DST_KEY *new_key = NULL;
int dnslen;
u_char dns[2048];
if (name == NULL)
return (NULL);
if (!dst_check_algorithm(alg)) { /*%< make sure alg is available */
EREPORT(("%s: Algorithm %d not supported\n", __func__, alg));
return (NULL);
}
new_key = dst_s_get_key_struct(name, alg, flags, protocol, bits);
if (new_key == NULL)
return (NULL);
if (bits == 0) /*%< null key we are done */
return (new_key);
if (new_key->dk_func == NULL || new_key->dk_func->generate == NULL) {
EREPORT(("%s: Unsupported algorithm %d\n", __func__, alg));
return (dst_free_key(new_key));
}
if (new_key->dk_func->generate(new_key, exp) <= 0) {
EREPORT(("%s: Key generation failure %s %d %d %d\n", __func__,
new_key->dk_key_name, new_key->dk_alg,
new_key->dk_key_size, exp));
return (dst_free_key(new_key));
}
dnslen = dst_key_to_dnskey(new_key, dns, (int)sizeof(dns));
if (dnslen != UNSUPPORTED_KEYALG)
new_key->dk_id = dst_s_dns_key_id(dns, dnslen);
else
new_key->dk_id = 0;
return (new_key);
}
/*%
* Release all data structures pointed to by a key structure.
*
* Parameters
*\li f_key Key structure to be freed.
*/
DST_KEY *
dst_free_key(DST_KEY *f_key)
{
if (f_key == NULL)
return (f_key);
if (f_key->dk_func && f_key->dk_func->destroy)
f_key->dk_KEY_struct =
f_key->dk_func->destroy(f_key->dk_KEY_struct);
else {
EREPORT(("%s: Unknown key alg %d\n", __func__, f_key->dk_alg));
}
if (f_key->dk_KEY_struct) {
free(f_key->dk_KEY_struct);
f_key->dk_KEY_struct = NULL;
}
if (f_key->dk_key_name)
SAFE_FREE(f_key->dk_key_name);
SAFE_FREE(f_key);
return (NULL);
}
/*%
* Return the maximum size of signature from the key specified in bytes
*
* Parameters
*\li key
*
* Returns
* \li bytes
*/
int
dst_sig_size(DST_KEY *key) {
switch (key->dk_alg) {
case KEY_HMAC_MD5:
return (16);
case KEY_HMAC_SHA1:
return (20);
case KEY_RSA:
return (key->dk_key_size + 7) / 8;
case KEY_DSA:
return (40);
default:
EREPORT(("%s: Unknown key alg %d\n", __func__, key->dk_alg));
return -1;
}
}
/*! \file */
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