111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
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* digest support for NTP, MD5 and with OpenSSL more
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include "ntp_fp.h"
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#include "ntp_string.h"
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#include "ntp_stdlib.h"
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#include "ntp.h"
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#ifdef OPENSSL
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# include "openssl/evp.h"
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#else
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# include "ntp_md5.h" /* provides clone of OpenSSL MD5 API */
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#endif
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/*
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* MD5authencrypt - generate message digest
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*
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* Returns length of MAC including key ID and digest.
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*/
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int
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MD5authencrypt(
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int type, /* hash algorithm */
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u_char *key, /* key pointer */
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u_int32 *pkt, /* packet pointer */
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int length /* packet length */
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)
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{
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u_char digest[EVP_MAX_MD_SIZE];
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u_int len;
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EVP_MD_CTX ctx;
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/*
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* Compute digest of key concatenated with packet. Note: the
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* key type and digest type have been verified when the key
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* was creaded.
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*/
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INIT_SSL();
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EVP_DigestInit(&ctx, EVP_get_digestbynid(type));
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EVP_DigestUpdate(&ctx, key, (u_int)cache_keylen);
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EVP_DigestUpdate(&ctx, (u_char *)pkt, (u_int)length);
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EVP_DigestFinal(&ctx, digest, &len);
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memmove((u_char *)pkt + length + 4, digest, len);
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return (len + 4);
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}
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/*
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* MD5authdecrypt - verify MD5 message authenticator
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*
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* Returns one if digest valid, zero if invalid.
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*/
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int
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MD5authdecrypt(
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int type, /* hash algorithm */
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u_char *key, /* key pointer */
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u_int32 *pkt, /* packet pointer */
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int length, /* packet length */
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int size /* MAC size */
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)
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{
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u_char digest[EVP_MAX_MD_SIZE];
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u_int len;
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EVP_MD_CTX ctx;
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/*
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* Compute digest of key concatenated with packet. Note: the
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* key type and digest type have been verified when the key
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* was created.
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*/
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INIT_SSL();
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EVP_DigestInit(&ctx, EVP_get_digestbynid(type));
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EVP_DigestUpdate(&ctx, key, (u_int)cache_keylen);
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EVP_DigestUpdate(&ctx, (u_char *)pkt, (u_int)length);
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EVP_DigestFinal(&ctx, digest, &len);
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if ((u_int)size != len + 4) {
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msyslog(LOG_ERR,
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"MAC decrypt: MAC length error");
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return (0);
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}
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return (!memcmp(digest, (char *)pkt + length + 4, len));
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}
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/*
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* Calculate the reference id from the address. If it is an IPv4
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* address, use it as is. If it is an IPv6 address, do a md5 on
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* it and use the bottom 4 bytes.
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* The result is in network byte order.
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*/
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u_int32
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addr2refid(sockaddr_u *addr)
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{
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u_char digest[20];
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u_int32 addr_refid;
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EVP_MD_CTX ctx;
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u_int len;
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if (IS_IPV4(addr))
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return (NSRCADR(addr));
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INIT_SSL();
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EVP_DigestInit(&ctx, EVP_get_digestbynid(NID_md5));
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EVP_DigestUpdate(&ctx, (u_char *)PSOCK_ADDR6(addr),
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sizeof(struct in6_addr));
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EVP_DigestFinal(&ctx, digest, &len);
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memcpy(&addr_refid, digest, 4);
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return (addr_refid);
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}
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