sha1-tlsprf.c
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00001 /*
00002  * TLS PRF (SHA1 + MD5)
00003  * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License version 2 as
00007  * published by the Free Software Foundation.
00008  *
00009  * Alternatively, this software may be distributed under the terms of BSD
00010  * license.
00011  *
00012  * See README and COPYING for more details.
00013  */
00014 
00015 #include "includes.h"
00016 
00017 #include "common.h"
00018 #include "sha1.h"
00019 #include "md5.h"
00020 #include "crypto.h"
00021 
00022 
00037 int tls_prf(const u8 *secret, size_t secret_len, const char *label,
00038             const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
00039 {
00040         size_t L_S1, L_S2, i;
00041         const u8 *S1, *S2;
00042         u8 A_MD5[MD5_MAC_LEN], A_SHA1[SHA1_MAC_LEN];
00043         u8 P_MD5[MD5_MAC_LEN], P_SHA1[SHA1_MAC_LEN];
00044         int MD5_pos, SHA1_pos;
00045         const u8 *MD5_addr[3];
00046         size_t MD5_len[3];
00047         const unsigned char *SHA1_addr[3];
00048         size_t SHA1_len[3];
00049 
00050         if (secret_len & 1)
00051                 return -1;
00052 
00053         MD5_addr[0] = A_MD5;
00054         MD5_len[0] = MD5_MAC_LEN;
00055         MD5_addr[1] = (unsigned char *) label;
00056         MD5_len[1] = os_strlen(label);
00057         MD5_addr[2] = seed;
00058         MD5_len[2] = seed_len;
00059 
00060         SHA1_addr[0] = A_SHA1;
00061         SHA1_len[0] = SHA1_MAC_LEN;
00062         SHA1_addr[1] = (unsigned char *) label;
00063         SHA1_len[1] = os_strlen(label);
00064         SHA1_addr[2] = seed;
00065         SHA1_len[2] = seed_len;
00066 
00067         /* RFC 2246, Chapter 5
00068          * A(0) = seed, A(i) = HMAC(secret, A(i-1))
00069          * P_hash = HMAC(secret, A(1) + seed) + HMAC(secret, A(2) + seed) + ..
00070          * PRF = P_MD5(S1, label + seed) XOR P_SHA-1(S2, label + seed)
00071          */
00072 
00073         L_S1 = L_S2 = (secret_len + 1) / 2;
00074         S1 = secret;
00075         S2 = secret + L_S1;
00076         if (secret_len & 1) {
00077                 /* The last byte of S1 will be shared with S2 */
00078                 S2--;
00079         }
00080 
00081         hmac_md5_vector_non_fips_allow(S1, L_S1, 2, &MD5_addr[1], &MD5_len[1],
00082                                        A_MD5);
00083         hmac_sha1_vector(S2, L_S2, 2, &SHA1_addr[1], &SHA1_len[1], A_SHA1);
00084 
00085         MD5_pos = MD5_MAC_LEN;
00086         SHA1_pos = SHA1_MAC_LEN;
00087         for (i = 0; i < outlen; i++) {
00088                 if (MD5_pos == MD5_MAC_LEN) {
00089                         hmac_md5_vector_non_fips_allow(S1, L_S1, 3, MD5_addr,
00090                                                        MD5_len, P_MD5);
00091                         MD5_pos = 0;
00092                         hmac_md5_non_fips_allow(S1, L_S1, A_MD5, MD5_MAC_LEN,
00093                                                 A_MD5);
00094                 }
00095                 if (SHA1_pos == SHA1_MAC_LEN) {
00096                         hmac_sha1_vector(S2, L_S2, 3, SHA1_addr, SHA1_len,
00097                                          P_SHA1);
00098                         SHA1_pos = 0;
00099                         hmac_sha1(S2, L_S2, A_SHA1, SHA1_MAC_LEN, A_SHA1);
00100                 }
00101 
00102                 out[i] = P_MD5[MD5_pos] ^ P_SHA1[SHA1_pos];
00103 
00104                 MD5_pos++;
00105                 SHA1_pos++;
00106         }
00107 
00108         return 0;
00109 }


wpa_supplicant
Author(s): Package maintained by Blaise Gassend
autogenerated on Thu Apr 24 2014 15:34:35