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https://github.com/vanhoefm/fragattacks.git
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44ec48ebfd
Commitc9e08af24fremoved the only user of the special case MD5 use that would be allowed in FIPS mode in tls_prf_sha1_md5(). Commit271dbf1594removed the file from the build, but left the implementation into the repository. To clean things up even further, remove this functionality completely since it is not expected to be needed for FIPS mode anymore. Signed-hostap: Jouni Malinen <j@w1.fi>
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/*
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* TLS PRF (SHA1 + MD5)
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* Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "sha1.h"
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#include "md5.h"
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/**
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* tls_prf_sha1_md5 - Pseudo-Random Function for TLS (TLS-PRF, RFC 2246)
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* @secret: Key for PRF
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* @secret_len: Length of the key in bytes
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* @label: A unique label for each purpose of the PRF
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* @seed: Seed value to bind into the key
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* @seed_len: Length of the seed
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* @out: Buffer for the generated pseudo-random key
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* @outlen: Number of bytes of key to generate
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* Returns: 0 on success, -1 on failure.
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*
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* This function is used to derive new, cryptographically separate keys from a
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* given key in TLS. This PRF is defined in RFC 2246, Chapter 5.
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*/
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int tls_prf_sha1_md5(const u8 *secret, size_t secret_len, const char *label,
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const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
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{
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size_t L_S1, L_S2, i;
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const u8 *S1, *S2;
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u8 A_MD5[MD5_MAC_LEN], A_SHA1[SHA1_MAC_LEN];
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u8 P_MD5[MD5_MAC_LEN], P_SHA1[SHA1_MAC_LEN];
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int MD5_pos, SHA1_pos;
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const u8 *MD5_addr[3];
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size_t MD5_len[3];
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const unsigned char *SHA1_addr[3];
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size_t SHA1_len[3];
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if (secret_len & 1)
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return -1;
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MD5_addr[0] = A_MD5;
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MD5_len[0] = MD5_MAC_LEN;
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MD5_addr[1] = (unsigned char *) label;
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MD5_len[1] = os_strlen(label);
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MD5_addr[2] = seed;
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MD5_len[2] = seed_len;
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SHA1_addr[0] = A_SHA1;
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SHA1_len[0] = SHA1_MAC_LEN;
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SHA1_addr[1] = (unsigned char *) label;
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SHA1_len[1] = os_strlen(label);
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SHA1_addr[2] = seed;
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SHA1_len[2] = seed_len;
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/* RFC 2246, Chapter 5
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* A(0) = seed, A(i) = HMAC(secret, A(i-1))
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* P_hash = HMAC(secret, A(1) + seed) + HMAC(secret, A(2) + seed) + ..
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* PRF = P_MD5(S1, label + seed) XOR P_SHA-1(S2, label + seed)
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*/
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L_S1 = L_S2 = (secret_len + 1) / 2;
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S1 = secret;
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S2 = secret + L_S1;
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if (secret_len & 1) {
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/* The last byte of S1 will be shared with S2 */
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S2--;
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}
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hmac_md5_vector(S1, L_S1, 2, &MD5_addr[1], &MD5_len[1], A_MD5);
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hmac_sha1_vector(S2, L_S2, 2, &SHA1_addr[1], &SHA1_len[1], A_SHA1);
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MD5_pos = MD5_MAC_LEN;
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SHA1_pos = SHA1_MAC_LEN;
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for (i = 0; i < outlen; i++) {
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if (MD5_pos == MD5_MAC_LEN) {
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hmac_md5_vector(S1, L_S1, 3, MD5_addr, MD5_len, P_MD5);
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MD5_pos = 0;
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hmac_md5(S1, L_S1, A_MD5, MD5_MAC_LEN, A_MD5);
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}
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if (SHA1_pos == SHA1_MAC_LEN) {
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hmac_sha1_vector(S2, L_S2, 3, SHA1_addr, SHA1_len,
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P_SHA1);
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SHA1_pos = 0;
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hmac_sha1(S2, L_S2, A_SHA1, SHA1_MAC_LEN, A_SHA1);
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}
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out[i] = P_MD5[MD5_pos] ^ P_SHA1[SHA1_pos];
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MD5_pos++;
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SHA1_pos++;
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}
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return 0;
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}
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