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Annotation of embedaddon/ntp/libntp/a_md5encrypt.c, revision 1.1

1.1     ! misho       1: /*
        !             2:  *     digest support for NTP, MD5 and with OpenSSL more
        !             3:  */
        !             4: #ifdef HAVE_CONFIG_H
        !             5: #include <config.h>
        !             6: #endif
        !             7: 
        !             8: #include "ntp_fp.h"
        !             9: #include "ntp_string.h"
        !            10: #include "ntp_stdlib.h"
        !            11: #include "ntp.h"
        !            12: #ifdef OPENSSL
        !            13: # include "openssl/evp.h"
        !            14: #else
        !            15: # include "ntp_md5.h"  /* provides clone of OpenSSL MD5 API */
        !            16: #endif
        !            17: 
        !            18: /*
        !            19:  * MD5authencrypt - generate message digest
        !            20:  *
        !            21:  * Returns length of MAC including key ID and digest.
        !            22:  */
        !            23: int
        !            24: MD5authencrypt(
        !            25:        int     type,           /* hash algorithm */
        !            26:        u_char  *key,           /* key pointer */
        !            27:        u_int32 *pkt,           /* packet pointer */
        !            28:        int     length          /* packet length */
        !            29:        )
        !            30: {
        !            31:        u_char  digest[EVP_MAX_MD_SIZE];
        !            32:        u_int   len;
        !            33:        EVP_MD_CTX ctx;
        !            34: 
        !            35:        /*
        !            36:         * Compute digest of key concatenated with packet. Note: the
        !            37:         * key type and digest type have been verified when the key
        !            38:         * was creaded.
        !            39:         */
        !            40:        INIT_SSL();
        !            41:        EVP_DigestInit(&ctx, EVP_get_digestbynid(type));
        !            42:        EVP_DigestUpdate(&ctx, key, (u_int)cache_keylen);
        !            43:        EVP_DigestUpdate(&ctx, (u_char *)pkt, (u_int)length);
        !            44:        EVP_DigestFinal(&ctx, digest, &len);
        !            45:        memmove((u_char *)pkt + length + 4, digest, len);
        !            46:        return (len + 4);
        !            47: }
        !            48: 
        !            49: 
        !            50: /*
        !            51:  * MD5authdecrypt - verify MD5 message authenticator
        !            52:  *
        !            53:  * Returns one if digest valid, zero if invalid.
        !            54:  */
        !            55: int
        !            56: MD5authdecrypt(
        !            57:        int     type,           /* hash algorithm */
        !            58:        u_char  *key,           /* key pointer */
        !            59:        u_int32 *pkt,           /* packet pointer */
        !            60:        int     length,         /* packet length */
        !            61:        int     size            /* MAC size */
        !            62:        )
        !            63: {
        !            64:        u_char  digest[EVP_MAX_MD_SIZE];
        !            65:        u_int   len;
        !            66:        EVP_MD_CTX ctx;
        !            67: 
        !            68:        /*
        !            69:         * Compute digest of key concatenated with packet. Note: the
        !            70:         * key type and digest type have been verified when the key
        !            71:         * was created.
        !            72:         */
        !            73:        INIT_SSL();
        !            74:        EVP_DigestInit(&ctx, EVP_get_digestbynid(type));
        !            75:        EVP_DigestUpdate(&ctx, key, (u_int)cache_keylen);
        !            76:        EVP_DigestUpdate(&ctx, (u_char *)pkt, (u_int)length);
        !            77:        EVP_DigestFinal(&ctx, digest, &len);
        !            78:        if ((u_int)size != len + 4) {
        !            79:                msyslog(LOG_ERR,
        !            80:                    "MAC decrypt: MAC length error");
        !            81:                return (0);
        !            82:        }
        !            83:        return (!memcmp(digest, (char *)pkt + length + 4, len));
        !            84: }
        !            85: 
        !            86: /*
        !            87:  * Calculate the reference id from the address. If it is an IPv4
        !            88:  * address, use it as is. If it is an IPv6 address, do a md5 on
        !            89:  * it and use the bottom 4 bytes.
        !            90:  * The result is in network byte order.
        !            91:  */
        !            92: u_int32
        !            93: addr2refid(sockaddr_u *addr)
        !            94: {
        !            95:        u_char          digest[20];
        !            96:        u_int32         addr_refid;
        !            97:        EVP_MD_CTX      ctx;
        !            98:        u_int           len;
        !            99: 
        !           100:        if (IS_IPV4(addr))
        !           101:                return (NSRCADR(addr));
        !           102: 
        !           103:        INIT_SSL();
        !           104:        EVP_DigestInit(&ctx, EVP_get_digestbynid(NID_md5));
        !           105:        EVP_DigestUpdate(&ctx, (u_char *)PSOCK_ADDR6(addr),
        !           106:            sizeof(struct in6_addr));
        !           107:        EVP_DigestFinal(&ctx, digest, &len);
        !           108:        memcpy(&addr_refid, digest, 4);
        !           109:        return (addr_refid);
        !           110: }