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Move SHA256-based PRF function into a separate C file

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This makes it easier to conditionally build in SHA256 functions based
on which TLS/crypto library is used.

Signed-hostap: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2012-08-16 22:24:11 +03:00
parent 0b5e98557e
commit ab637dcb37
6 changed files with 68 additions and 51 deletions
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1
hostapd/Android.mk
View file

@ -721,6 +721,7 @@ endif
ifdef NEED_SHA256
OBJS += src/crypto/sha256.c
OBJS += src/crypto/sha256-prf.c
ifdef CONFIG_INTERNAL_SHA256
OBJS += src/crypto/sha256-internal.c
endif

1
hostapd/Makefile
View file

@ -713,6 +713,7 @@ endif
ifdef NEED_SHA256
CFLAGS += -DCONFIG_SHA256
OBJS += ../src/crypto/sha256.o
OBJS += ../src/crypto/sha256-prf.o
ifdef CONFIG_INTERNAL_SHA256
OBJS += ../src/crypto/sha256-internal.o
endif

64
src/crypto/sha256-prf.c Normal file
View file

@ -0,0 +1,64 @@
/*
* SHA256-based PRF (IEEE 802.11r)
* Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "sha256.h"
#include "crypto.h"
/**
* sha256_prf - SHA256-based Pseudo-Random Function (IEEE 802.11r, 8.5.1.5.2)
* @key: Key for PRF
* @key_len: Length of the key in bytes
* @label: A unique label for each purpose of the PRF
* @data: Extra data to bind into the key
* @data_len: Length of the data
* @buf: Buffer for the generated pseudo-random key
* @buf_len: Number of bytes of key to generate
*
* This function is used to derive new, cryptographically separate keys from a
* given key.
*/
void sha256_prf(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
{
u16 counter = 1;
size_t pos, plen;
u8 hash[SHA256_MAC_LEN];
const u8 *addr[4];
size_t len[4];
u8 counter_le[2], length_le[2];
addr[0] = counter_le;
len[0] = 2;
addr[1] = (u8 *) label;
len[1] = os_strlen(label);
addr[2] = data;
len[2] = data_len;
addr[3] = length_le;
len[3] = sizeof(length_le);
WPA_PUT_LE16(length_le, buf_len * 8);
pos = 0;
while (pos < buf_len) {
plen = buf_len - pos;
WPA_PUT_LE16(counter_le, counter);
if (plen >= SHA256_MAC_LEN) {
hmac_sha256_vector(key, key_len, 4, addr, len,
&buf[pos]);
pos += SHA256_MAC_LEN;
} else {
hmac_sha256_vector(key, key_len, 4, addr, len, hash);
os_memcpy(&buf[pos], hash, plen);
break;
}
counter++;
}
}

51
src/crypto/sha256.c
View file

@ -98,54 +98,3 @@ void hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
{
hmac_sha256_vector(key, key_len, 1, &data, &data_len, mac);
}
/**
* sha256_prf - SHA256-based Pseudo-Random Function (IEEE 802.11r, 8.5.1.5.2)
* @key: Key for PRF
* @key_len: Length of the key in bytes
* @label: A unique label for each purpose of the PRF
* @data: Extra data to bind into the key
* @data_len: Length of the data
* @buf: Buffer for the generated pseudo-random key
* @buf_len: Number of bytes of key to generate
*
* This function is used to derive new, cryptographically separate keys from a
* given key.
*/
void sha256_prf(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
{
u16 counter = 1;
size_t pos, plen;
u8 hash[SHA256_MAC_LEN];
const u8 *addr[4];
size_t len[4];
u8 counter_le[2], length_le[2];
addr[0] = counter_le;
len[0] = 2;
addr[1] = (u8 *) label;
len[1] = os_strlen(label);
addr[2] = data;
len[2] = data_len;
addr[3] = length_le;
len[3] = sizeof(length_le);
WPA_PUT_LE16(length_le, buf_len * 8);
pos = 0;
while (pos < buf_len) {
plen = buf_len - pos;
WPA_PUT_LE16(counter_le, counter);
if (plen >= SHA256_MAC_LEN) {
hmac_sha256_vector(key, key_len, 4, addr, len,
&buf[pos]);
pos += SHA256_MAC_LEN;
} else {
hmac_sha256_vector(key, key_len, 4, addr, len, hash);
os_memcpy(&buf[pos], hash, plen);
break;
}
counter++;
}
}

1
wpa_supplicant/Android.mk
View file

@ -1123,6 +1123,7 @@ SHA256OBJS = # none by default
ifdef NEED_SHA256
L_CFLAGS += -DCONFIG_SHA256
SHA256OBJS += src/crypto/sha256.c
SHA256OBJS += src/crypto/sha256-prf.c
ifdef CONFIG_INTERNAL_SHA256
SHA256OBJS += src/crypto/sha256-internal.c
endif

1
wpa_supplicant/Makefile
View file

@ -1154,6 +1154,7 @@ SHA256OBJS = # none by default
ifdef NEED_SHA256
CFLAGS += -DCONFIG_SHA256
SHA256OBJS += ../src/crypto/sha256.o
SHA256OBJS += ../src/crypto/sha256-prf.o
ifdef CONFIG_INTERNAL_SHA256
SHA256OBJS += ../src/crypto/sha256-internal.o
endif