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Crypto build cleanup: remove CONFIG_NO_PBKDF2

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Instead of using a define and conditional building of sha1.c parts,
move the PBKDF2 implementation into a separate file.
This commit is contained in:
Johannes Berg 2009-08-11 20:31:39 +03:00 committed by Jouni Malinen
parent d9feab18fc
commit 18abe7acb0
4 changed files with 94 additions and 79 deletions
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2
hostapd/Makefile
View file

@ -38,7 +38,7 @@ CFLAGS += -DCONFIG_NATIVE_WINDOWS
LIBS += -lws2_32
endif
SHA1OBJS = ../src/crypto/sha1.o
SHA1OBJS = ../src/crypto/sha1.o ../src/crypto/sha1-pbkdf2.o
OBJS = hostapd.o main.o ieee802_1x.o eapol_sm.o \
config.o ieee802_11_auth.o \

91
src/crypto/sha1-pbkdf2.c Normal file
View file

@ -0,0 +1,91 @@
/*
* SHA1-based key derivation function (PBKDF2) for IEEE 802.11i
* Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "common.h"
#include "sha1.h"
#include "md5.h"
#include "crypto.h"
static void pbkdf2_sha1_f(const char *passphrase, const char *ssid,
size_t ssid_len, int iterations, unsigned int count,
u8 *digest)
{
unsigned char tmp[SHA1_MAC_LEN], tmp2[SHA1_MAC_LEN];
int i, j;
unsigned char count_buf[4];
const u8 *addr[2];
size_t len[2];
size_t passphrase_len = os_strlen(passphrase);
addr[0] = (u8 *) ssid;
len[0] = ssid_len;
addr[1] = count_buf;
len[1] = 4;
/* F(P, S, c, i) = U1 xor U2 xor ... Uc
* U1 = PRF(P, S || i)
* U2 = PRF(P, U1)
* Uc = PRF(P, Uc-1)
*/
count_buf[0] = (count >> 24) & 0xff;
count_buf[1] = (count >> 16) & 0xff;
count_buf[2] = (count >> 8) & 0xff;
count_buf[3] = count & 0xff;
hmac_sha1_vector((u8 *) passphrase, passphrase_len, 2, addr, len, tmp);
os_memcpy(digest, tmp, SHA1_MAC_LEN);
for (i = 1; i < iterations; i++) {
hmac_sha1((u8 *) passphrase, passphrase_len, tmp, SHA1_MAC_LEN,
tmp2);
os_memcpy(tmp, tmp2, SHA1_MAC_LEN);
for (j = 0; j < SHA1_MAC_LEN; j++)
digest[j] ^= tmp2[j];
}
}
/**
* pbkdf2_sha1 - SHA1-based key derivation function (PBKDF2) for IEEE 802.11i
* @passphrase: ASCII passphrase
* @ssid: SSID
* @ssid_len: SSID length in bytes
* @iterations: Number of iterations to run
* @buf: Buffer for the generated key
* @buflen: Length of the buffer in bytes
*
* This function is used to derive PSK for WPA-PSK. For this protocol,
* iterations is set to 4096 and buflen to 32. This function is described in
* IEEE Std 802.11-2004, Clause H.4. The main construction is from PKCS#5 v2.0.
*/
void pbkdf2_sha1(const char *passphrase, const char *ssid, size_t ssid_len,
int iterations, u8 *buf, size_t buflen)
{
unsigned int count = 0;
unsigned char *pos = buf;
size_t left = buflen, plen;
unsigned char digest[SHA1_MAC_LEN];
while (left > 0) {
count++;
pbkdf2_sha1_f(passphrase, ssid, ssid_len, iterations, count,
digest);
plen = left > SHA1_MAC_LEN ? SHA1_MAC_LEN : left;
os_memcpy(pos, digest, plen);
pos += plen;
left -= plen;
}
}

76
src/crypto/sha1.c
View file

@ -152,79 +152,3 @@ void sha1_prf(const u8 *key, size_t key_len, const char *label,
counter++;
}
}
#ifndef CONFIG_NO_PBKDF2
static void pbkdf2_sha1_f(const char *passphrase, const char *ssid,
size_t ssid_len, int iterations, unsigned int count,
u8 *digest)
{
unsigned char tmp[SHA1_MAC_LEN], tmp2[SHA1_MAC_LEN];
int i, j;
unsigned char count_buf[4];
const u8 *addr[2];
size_t len[2];
size_t passphrase_len = os_strlen(passphrase);
addr[0] = (u8 *) ssid;
len[0] = ssid_len;
addr[1] = count_buf;
len[1] = 4;
/* F(P, S, c, i) = U1 xor U2 xor ... Uc
* U1 = PRF(P, S || i)
* U2 = PRF(P, U1)
* Uc = PRF(P, Uc-1)
*/
count_buf[0] = (count >> 24) & 0xff;
count_buf[1] = (count >> 16) & 0xff;
count_buf[2] = (count >> 8) & 0xff;
count_buf[3] = count & 0xff;
hmac_sha1_vector((u8 *) passphrase, passphrase_len, 2, addr, len, tmp);
os_memcpy(digest, tmp, SHA1_MAC_LEN);
for (i = 1; i < iterations; i++) {
hmac_sha1((u8 *) passphrase, passphrase_len, tmp, SHA1_MAC_LEN,
tmp2);
os_memcpy(tmp, tmp2, SHA1_MAC_LEN);
for (j = 0; j < SHA1_MAC_LEN; j++)
digest[j] ^= tmp2[j];
}
}
/**
* pbkdf2_sha1 - SHA1-based key derivation function (PBKDF2) for IEEE 802.11i
* @passphrase: ASCII passphrase
* @ssid: SSID
* @ssid_len: SSID length in bytes
* @iterations: Number of iterations to run
* @buf: Buffer for the generated key
* @buflen: Length of the buffer in bytes
*
* This function is used to derive PSK for WPA-PSK. For this protocol,
* iterations is set to 4096 and buflen to 32. This function is described in
* IEEE Std 802.11-2004, Clause H.4. The main construction is from PKCS#5 v2.0.
*/
void pbkdf2_sha1(const char *passphrase, const char *ssid, size_t ssid_len,
int iterations, u8 *buf, size_t buflen)
{
unsigned int count = 0;
unsigned char *pos = buf;
size_t left = buflen, plen;
unsigned char digest[SHA1_MAC_LEN];
while (left > 0) {
count++;
pbkdf2_sha1_f(passphrase, ssid, ssid_len, iterations, count,
digest);
plen = left > SHA1_MAC_LEN ? SHA1_MAC_LEN : left;
os_memcpy(pos, digest, plen);
pos += plen;
left -= plen;
}
}
#endif /* CONFIG_NO_PBKDF2 */

4
wpa_supplicant/Makefile
View file

@ -1066,8 +1066,8 @@ ifdef CONFIG_NO_WPA2
CFLAGS += -DCONFIG_NO_WPA2
endif
ifdef CONFIG_NO_WPA_PASSPHRASE
CFLAGS += -DCONFIG_NO_PBKDF2
ifndef CONFIG_NO_WPA_PASSPHRASE
SHA1OBJS += ../src/crypto/sha1-pbkdf2.o
endif
ifdef CONFIG_NO_AES_EXTRAS