wpa_tkip.c File Reference

Backend for WPA using the TKIP encryption standard. More...

#include <string.h>
#include <ipxe/net80211.h>
#include <ipxe/crypto.h>
#include <ipxe/hmac.h>
#include <ipxe/sha1.h>
#include <ipxe/md5.h>
#include <ipxe/crc32.h>
#include <ipxe/arc4.h>
#include <ipxe/wpa.h>
#include <byteswap.h>
#include <errno.h>

Go to the source code of this file.

Data Structures
struct	tkip_dir_ctx
	Context for one direction of TKIP, either encryption or decryption. More...
struct	tkip_ctx
	Context for TKIP encryption and decryption. More...
struct	tkip_head
	Header structure at the beginning of TKIP frame data. More...

Macros
#define	TKIP_HEAD_LEN   8
	TKIP header overhead (IV + KID + ExtIV)
#define	TKIP_FOOT_LEN   12
	TKIP trailer overhead (MIC + ICV) [assumes unfragmented].
#define	TKIP_MIC_LEN   8
	TKIP MIC length.
#define	TKIP_ICV_LEN   4
	TKIP ICV length.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
	FILE_SECBOOT (FORBIDDEN)
static u16	S (u16 v)
	Perform S-box mapping on a 16-bit value.
static u16	ror16 (u16 v, int bits)
	Rotate 16-bit value right.
static u32	ror32 (u32 v, int bits)
	Rotate 32-bit value right.
static u32	rol32 (u32 v, int bits)
	Rotate 32-bit value left.
static int	tkip_init (struct net80211_crypto *crypto, const void *key, int keylen, const void *rsc)
	Initialise TKIP state and install key.
static void	tkip_mix_1 (struct tkip_dir_ctx *dctx, struct tkip_tk *tk, u8 *mac)
	Perform TKIP key mixing, phase 1.
static void	tkip_mix_2 (struct tkip_dir_ctx *dctx, struct tkip_tk *tk, void *key)
	Perform TKIP key mixing, phase 2.
static void	tkip_feed_michael (u32 *V, u32 word)
	Update Michael message integrity code based on next 32-bit word of data.
static void	tkip_michael (const void *key, const void *da, const void *sa, const void *data, size_t len, void *mic)
	Calculate Michael message integrity code.
static struct io_buffer *	tkip_encrypt (struct net80211_crypto *crypto, struct io_buffer *iob)
	Encrypt a packet using TKIP.
static struct io_buffer *	tkip_decrypt (struct net80211_crypto *crypto, struct io_buffer *eiob)
	Decrypt a packet using TKIP.
static void	tkip_kie_mic (const void *kck, const void *msg, size_t len, void *mic)
	Calculate HMAC-MD5 MIC for EAPOL-Key frame.
static int	tkip_kie_decrypt (const void *kek, const void *iv, void *msg, u16 *len)
	Decrypt key data in EAPOL-Key frame.

Variables
static const u16	Sbox [256]
	TKIP S-box.
struct net80211_crypto tkip_crypto	__net80211_crypto
	TKIP cryptosystem.
struct wpa_kie tkip_kie	__wpa_kie
	TKIP-style key integrity and encryption handler.

Detailed Description

Backend for WPA using the TKIP encryption standard.

Definition in file wpa_tkip.c.

Macro Definition Documentation

TKIP_HEAD_LEN

#define TKIP_HEAD_LEN   8

TKIP header overhead (IV + KID + ExtIV)

Definition at line 84 of file wpa_tkip.c.

Referenced by tkip_decrypt(), and tkip_encrypt().

TKIP_FOOT_LEN

#define TKIP_FOOT_LEN   12

TKIP trailer overhead (MIC + ICV) [assumes unfragmented].

Definition at line 87 of file wpa_tkip.c.

Referenced by tkip_decrypt(), and tkip_encrypt().

TKIP_MIC_LEN

#define TKIP_MIC_LEN   8

TKIP MIC length.

Definition at line 90 of file wpa_tkip.c.

Referenced by tkip_decrypt().

TKIP_ICV_LEN

#define TKIP_ICV_LEN   4

TKIP ICV length.

Definition at line 93 of file wpa_tkip.c.

Referenced by tkip_encrypt().

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER

)

FILE_SECBOOT()

FILE_SECBOOT

(

FORBIDDEN

)

S()

u16 S ( u16 v )

inlinestatic

Perform S-box mapping on a 16-bit value.

Parameters

v	Value to perform S-box mapping on

Return values

Sv	S-box mapped value

Definition at line 138 of file wpa_tkip.c.

{
        return Sbox[v & 0xFF] ^ bswap_16 ( Sbox[v >> 8] );
}

References bswap_16, Sbox, and u16.

Referenced by arc4_setkey(), arc4_xor(), ccmp_ctr_xor(), tkip_mix_1(), and tkip_mix_2().

ror16()

u16 ror16 ( u16 v, int bits )

inlinestatic

Rotate 16-bit value right.

Parameters

v	Value to rotate
bits	Number of bits to rotate by

Return values

rotv	Rotated value

Definition at line 150 of file wpa_tkip.c.

{
        return ( v >> bits ) | ( v << ( 16 - bits ) );
}

References bits, and u16.

Referenced by tkip_mix_2().

ror32()

u32 ror32 ( u32 v, int bits )

inlinestatic

Rotate 32-bit value right.

Parameters

v	Value to rotate
bits	Number of bits to rotate by

Return values

rotv	Rotated value

Definition at line 162 of file wpa_tkip.c.

{
        return ( v >> bits ) | ( v << ( 32 - bits ) );
}

References bits, and u32.

Referenced by aes_key_rotate(), des_generate(), sha256_digest(), and tkip_feed_michael().

rol32()

u32 rol32 ( u32 v, int bits )

inlinestatic

Rotate 32-bit value left.

Parameters

v	Value to rotate
bits	Number of bits to rotate by

Return values

rotv	Rotated value

Definition at line 174 of file wpa_tkip.c.

{
        return ( v << bits ) | ( v >> ( 32 - bits ) );
}

References bits, and u32.

Referenced by aes_key_rotate(), aes_key_sbox(), des_rol28(), des_sbox(), md4_digest(), md5_digest(), sha1_digest(), and tkip_feed_michael().

tkip_init()

int tkip_init ( struct net80211_crypto * crypto, const void * key, int keylen, const void * rsc )

static

Initialise TKIP state and install key.

Parameters

crypto	TKIP cryptosystem structure
key	Pointer to tkip_tk to install
keylen	Length of key (32 bytes)
rsc	Initial receive sequence counter

Definition at line 188 of file wpa_tkip.c.

{
        struct tkip_ctx *ctx = crypto->priv;
        const u8 *rscb = rsc;
 
        if ( keylen != sizeof ( ctx->tk ) )
                return -EINVAL;
 
        if ( rscb ) {
                ctx->dec.tsc_lo =   ( rscb[1] <<  8 ) |   rscb[0];
                ctx->dec.tsc_hi = ( ( rscb[5] << 24 ) | ( rscb[4] << 16 ) |
                                    ( rscb[3] <<  8 ) |   rscb[2] );
        }
 
        memcpy ( &ctx->tk, key, sizeof ( ctx->tk ) );
 
        return 0;
}

References ctx, EINVAL, key, memcpy(), net80211_crypto::priv, rsc, and u8.

tkip_mix_1()

void tkip_mix_1 ( struct tkip_dir_ctx * dctx, struct tkip_tk * tk, u8 * mac )

static

Perform TKIP key mixing, phase 1.

Parameters

dctx	TKIP directional context
tk	TKIP temporal key
mac	MAC address of transmitter

This recomputes the TTAK in dctx if necessary, and sets dctx->ttak_ok.

Definition at line 218 of file wpa_tkip.c.

{
        int i, j;
 
        if ( dctx->ttak_ok && ! memcmp ( mac, dctx->mac, ETH_ALEN ) )
                return;
 
        memcpy ( dctx->mac, mac, ETH_ALEN );
 
        dctx->ttak[0] = dctx->tsc_hi & 0xFFFF;
        dctx->ttak[1] = dctx->tsc_hi >> 16;
        dctx->ttak[2] = ( mac[1] << 8 ) | mac[0];
        dctx->ttak[3] = ( mac[3] << 8 ) | mac[2];
        dctx->ttak[4] = ( mac[5] << 8 ) | mac[4];
 
        for ( i = 0; i < 8; i++ ) {
                j = 2 * ( i & 1 );
 
                dctx->ttak[0] += S ( dctx->ttak[4] ^ ( ( tk->key[1 + j] << 8 ) |
                                                         tk->key[0 + j] ) );
                dctx->ttak[1] += S ( dctx->ttak[0] ^ ( ( tk->key[5 + j] << 8 ) |
                                                         tk->key[4 + j] ) );
                dctx->ttak[2] += S ( dctx->ttak[1] ^ ( ( tk->key[9 + j] << 8 ) |
                                                         tk->key[8 + j] ) );
                dctx->ttak[3] += S ( dctx->ttak[2] ^ ( ( tk->key[13+ j] << 8 ) |
                                                         tk->key[12+ j] ) );
                dctx->ttak[4] += S ( dctx->ttak[3] ^ ( ( tk->key[1 + j] << 8 ) |
                                                         tk->key[0 + j] ) ) + i;
        }
 
        dctx->ttak_ok = 1;
}

References ETH_ALEN, mac, tkip_dir_ctx::mac, memcmp(), memcpy(), S(), tk, tkip_dir_ctx::tsc_hi, tkip_dir_ctx::ttak, tkip_dir_ctx::ttak_ok, and u8.

Referenced by tkip_decrypt(), and tkip_encrypt().

tkip_mix_2()

void tkip_mix_2 ( struct tkip_dir_ctx * dctx, struct tkip_tk * tk, void * key )

static

Perform TKIP key mixing, phase 2.

Parameters

dctx	TKIP directional context
tk	TKIP temporal key

Return values

key	ARC4 key, 16 bytes long

Definition at line 258 of file wpa_tkip.c.

{
        u8 *kb = key;
        u16 ppk[6];
        int i;
 
        memcpy ( ppk, dctx->ttak, sizeof ( dctx->ttak ) );
        ppk[5] = dctx->ttak[4] + dctx->tsc_lo;
 
        ppk[0] += S ( ppk[5] ^ ( ( tk->key[1] << 8 ) | tk->key[0] ) );
        ppk[1] += S ( ppk[0] ^ ( ( tk->key[3] << 8 ) | tk->key[2] ) );
        ppk[2] += S ( ppk[1] ^ ( ( tk->key[5] << 8 ) | tk->key[4] ) );
        ppk[3] += S ( ppk[2] ^ ( ( tk->key[7] << 8 ) | tk->key[6] ) );
        ppk[4] += S ( ppk[3] ^ ( ( tk->key[9] << 8 ) | tk->key[8] ) );
        ppk[5] += S ( ppk[4] ^ ( ( tk->key[11] << 8 ) | tk->key[10] ) );
 
        ppk[0] += ror16 ( ppk[5] ^ ( ( tk->key[13] << 8 ) | tk->key[12] ), 1 );
        ppk[1] += ror16 ( ppk[0] ^ ( ( tk->key[15] << 8 ) | tk->key[14] ), 1 );
        ppk[2] += ror16 ( ppk[1], 1 );
        ppk[3] += ror16 ( ppk[2], 1 );
        ppk[4] += ror16 ( ppk[3], 1 );
        ppk[5] += ror16 ( ppk[4], 1 );
 
        kb[0] = dctx->tsc_lo >> 8;
        kb[1] = ( ( dctx->tsc_lo >> 8 ) | 0x20 ) & 0x7F;
        kb[2] = dctx->tsc_lo & 0xFF;
        kb[3] = ( ( ppk[5] ^ ( ( tk->key[1] << 8 ) | tk->key[0] ) ) >> 1 )
                & 0xFF;
 
        for ( i = 0; i < 6; i++ ) {
                kb[4 + 2*i] = ppk[i] & 0xFF;
                kb[5 + 2*i] = ppk[i] >> 8;
        }
}

References key, memcpy(), ror16(), S(), tk, tkip_dir_ctx::tsc_lo, tkip_dir_ctx::ttak, u16, and u8.

Referenced by tkip_decrypt(), and tkip_encrypt().

tkip_feed_michael()

void tkip_feed_michael ( u32 * V, u32 word )

static

Update Michael message integrity code based on next 32-bit word of data.

Parameters

V	Michael code state (two 32-bit words)
word	Next 32-bit word of data

Definition at line 300 of file wpa_tkip.c.

{
        V[0] ^= word;
        V[1] ^= rol32 ( V[0], 17 );
        V[0] += V[1];
        V[1] ^= ( ( V[0] & 0xFF00FF00 ) >> 8 ) | ( ( V[0] & 0x00FF00FF ) << 8 );
        V[0] += V[1];
        V[1] ^= rol32 ( V[0], 3 );
        V[0] += V[1];
        V[1] ^= ror32 ( V[0], 2 );
        V[0] += V[1];
}

References rol32(), ror32(), and u32.

Referenced by tkip_michael().

tkip_michael()

void tkip_michael ( const void * key, const void * da, const void * sa, const void * data, size_t len, void * mic )

static

Calculate Michael message integrity code.

Parameters

key	MIC key to use (8 bytes)
da	Destination link-layer address
sa	Source link-layer address
data	Start of data to calculate over
len	Length of header + data

Return values

mic	Calculated Michael MIC (8 bytes)

Definition at line 323 of file wpa_tkip.c.

{
        u32 V[2];            /* V[0] = "l", V[1] = "r" in 802.11 */
        union {
                u8 byte[12];
                u32 word[3];
        } cap;
        const u8 *ptr = data;
        const u8 *end = ptr + len;
        int i;
 
        memcpy ( V, key, sizeof ( V ) );
        V[0] = le32_to_cpu ( V[0] );
        V[1] = le32_to_cpu ( V[1] );
 
        /* Feed in header (we assume non-QoS, so Priority = 0) */
        memcpy ( &cap.byte[0], da, ETH_ALEN );
        memcpy ( &cap.byte[6], sa, ETH_ALEN );
        tkip_feed_michael ( V, le32_to_cpu ( cap.word[0] ) );
        tkip_feed_michael ( V, le32_to_cpu ( cap.word[1] ) );
        tkip_feed_michael ( V, le32_to_cpu ( cap.word[2] ) );
        tkip_feed_michael ( V, 0 );
 
        /* Feed in data */
        while ( ptr + 4 <= end ) {
                tkip_feed_michael ( V, le32_to_cpu ( *( u32 * ) ptr ) );
                ptr += 4;
        }
 
        /* Add unaligned part and padding */
        for ( i = 0; ptr < end; i++ )
                cap.byte[i] = *ptr++;
        cap.byte[i++] = 0x5a;
        for ( ; i < 8; i++ )
                cap.byte[i] = 0;
 
        /* Feed in padding */
        tkip_feed_michael ( V, le32_to_cpu ( cap.word[0] ) );
        tkip_feed_michael ( V, le32_to_cpu ( cap.word[1] ) );
 
        /* Output MIC */
        V[0] = cpu_to_le32 ( V[0] );
        V[1] = cpu_to_le32 ( V[1] );
        memcpy ( mic, V, sizeof ( V ) );
}

References cpu_to_le32, data, end, ETH_ALEN, key, le32_to_cpu, len, memcpy(), mic, sa, tkip_feed_michael(), u32, and u8.

Referenced by tkip_decrypt(), and tkip_encrypt().

tkip_encrypt()

struct io_buffer * tkip_encrypt ( struct net80211_crypto * crypto, struct io_buffer * iob )

static

Encrypt a packet using TKIP.

Parameters

crypto	TKIP cryptosystem
iob	I/O buffer containing cleartext packet

Return values

eiob	I/O buffer containing encrypted packet

Definition at line 377 of file wpa_tkip.c.

{
        struct tkip_ctx *ctx = crypto->priv;
        struct ieee80211_frame *hdr = iob->data;
        struct io_buffer *eiob;
        struct arc4_ctx arc4;
        u8 key[16];
        struct tkip_head head;
        u8 mic[8];
        u32 icv;
        const int hdrlen = IEEE80211_TYP_FRAME_HEADER_LEN;
        int datalen = iob_len ( iob ) - hdrlen;
 
        ctx->enc.tsc_lo++;
        if ( ctx->enc.tsc_lo == 0 ) {
                ctx->enc.tsc_hi++;
                ctx->enc.ttak_ok = 0;
        }
 
        tkip_mix_1 ( &ctx->enc, &ctx->tk, hdr->addr2 );
        tkip_mix_2 ( &ctx->enc, &ctx->tk, key );
 
        eiob = alloc_iob ( iob_len ( iob ) + TKIP_HEAD_LEN + TKIP_FOOT_LEN );
        if ( ! eiob )
                return NULL;
 
        /* Copy frame header */
        memcpy ( iob_put ( eiob, hdrlen ), iob->data, hdrlen );
        hdr = eiob->data;
        hdr->fc |= IEEE80211_FC_PROTECTED;
 
        /* Fill in IV and key ID byte, and extended IV */
        memcpy ( &head, key, 3 );
        head.kid = 0x20;            /* have Extended IV, key ID 0 */
        head.tsc_hi = cpu_to_le32 ( ctx->enc.tsc_hi );
        memcpy ( iob_put ( eiob, sizeof ( head ) ), &head, sizeof ( head ) );
 
        /* Copy and encrypt the data */
        cipher_setkey ( &arc4_algorithm, &arc4, key, 16 );
        cipher_encrypt ( &arc4_algorithm, &arc4, iob->data + hdrlen,
                         iob_put ( eiob, datalen ), datalen );
 
        /* Add MIC */
        hdr = iob->data;
        tkip_michael ( &ctx->tk.mic.tx, hdr->addr3, hdr->addr2,
                       iob->data + hdrlen, datalen, mic );
        cipher_encrypt ( &arc4_algorithm, &arc4, mic,
                         iob_put ( eiob, sizeof ( mic ) ), sizeof ( mic ) );
 
        /* Add ICV */
        icv = crc32_le ( ~0, iob->data + hdrlen, datalen );
        icv = crc32_le ( icv, mic, sizeof ( mic ) );
        icv = cpu_to_le32 ( ~icv );
        cipher_encrypt ( &arc4_algorithm, &arc4, &icv,
                         iob_put ( eiob, TKIP_ICV_LEN ), TKIP_ICV_LEN );
 
        DBGC2 ( ctx, "WPA-TKIP %p: encrypted packet %p -> %p\n", ctx,
                iob, eiob );
 
        return eiob;
}

References alloc_iob(), arc4_algorithm, cipher_encrypt, cipher_setkey(), cpu_to_le32, crc32_le(), ctx, io_buffer::data, datalen, DBGC2, hdr, head, IEEE80211_FC_PROTECTED, IEEE80211_TYP_FRAME_HEADER_LEN, iob_len(), iob_put, key, memcpy(), mic, NULL, net80211_crypto::priv, TKIP_FOOT_LEN, TKIP_HEAD_LEN, TKIP_ICV_LEN, tkip_michael(), tkip_mix_1(), tkip_mix_2(), u32, and u8.

tkip_decrypt()

struct io_buffer * tkip_decrypt ( struct net80211_crypto * crypto, struct io_buffer * eiob )

static

Decrypt a packet using TKIP.

Parameters

crypto	TKIP cryptosystem
eiob	I/O buffer containing encrypted packet

Return values

iob	I/O buffer containing cleartext packet

Definition at line 447 of file wpa_tkip.c.

{
        struct tkip_ctx *ctx = crypto->priv;
        struct ieee80211_frame *hdr;
        struct io_buffer *iob;
        const int hdrlen = IEEE80211_TYP_FRAME_HEADER_LEN;
        int datalen = iob_len ( eiob ) - hdrlen - TKIP_HEAD_LEN - TKIP_FOOT_LEN;
        struct tkip_head *head;
        struct arc4_ctx arc4;
        u16 rx_tsc_lo;
        u8 key[16];
        u8 mic[8];
        u32 icv, crc;
 
        iob = alloc_iob ( hdrlen + datalen + TKIP_FOOT_LEN );
        if ( ! iob )
                return NULL;
 
        /* Copy frame header */
        memcpy ( iob_put ( iob, hdrlen ), eiob->data, hdrlen );
        hdr = iob->data;
        hdr->fc &= ~IEEE80211_FC_PROTECTED;
 
        /* Check and update TSC */
        head = eiob->data + hdrlen;
        rx_tsc_lo = ( head->tsc1 << 8 ) | head->tsc0;
 
        if ( head->tsc_hi < ctx->dec.tsc_hi ||
             ( head->tsc_hi == ctx->dec.tsc_hi &&
               rx_tsc_lo <= ctx->dec.tsc_lo ) ) {
                DBGC ( ctx, "WPA-TKIP %p: packet received out of order "
                       "(%08x:%04x <= %08x:%04x)\n", ctx, head->tsc_hi,
                       rx_tsc_lo, ctx->dec.tsc_hi, ctx->dec.tsc_lo );
                free_iob ( iob );
                return NULL;
        }
        ctx->dec.tsc_lo = rx_tsc_lo;
        if ( ctx->dec.tsc_hi != head->tsc_hi ) {
                ctx->dec.ttak_ok = 0;
                ctx->dec.tsc_hi = head->tsc_hi;
        }
 
        /* Calculate key */
        tkip_mix_1 ( &ctx->dec, &ctx->tk, hdr->addr2 );
        tkip_mix_2 ( &ctx->dec, &ctx->tk, key );
 
        /* Copy-decrypt data, MIC, ICV */
        cipher_setkey ( &arc4_algorithm, &arc4, key, 16 );
        cipher_decrypt ( &arc4_algorithm, &arc4,
                         eiob->data + hdrlen + TKIP_HEAD_LEN,
                         iob_put ( iob, datalen ), datalen + TKIP_FOOT_LEN );
 
        /* Check ICV */
        icv = le32_to_cpu ( *( u32 * ) ( iob->tail + TKIP_MIC_LEN ) );
        crc = ~crc32_le ( ~0, iob->data + hdrlen, datalen + TKIP_MIC_LEN );
        if ( crc != icv ) {
                DBGC ( ctx, "WPA-TKIP %p CRC mismatch: expect %08x, get %08x\n",
                       ctx, icv, crc );
                free_iob ( iob );
                return NULL;
        }
 
        /* Check MIC */
        tkip_michael ( &ctx->tk.mic.rx, hdr->addr1, hdr->addr3,
                       iob->data + hdrlen, datalen, mic );
        if ( memcmp ( mic, iob->tail, TKIP_MIC_LEN ) != 0 ) {
                DBGC ( ctx, "WPA-TKIP %p ALERT! MIC failure\n", ctx );
                /* XXX we should do the countermeasures here */
                free_iob ( iob );
                return NULL;
        }
 
        DBGC2 ( ctx, "WPA-TKIP %p: decrypted packet %p -> %p\n", ctx,
                eiob, iob );
 
        return iob;
}

References alloc_iob(), arc4_algorithm, cipher_decrypt, cipher_setkey(), crc32_le(), ctx, io_buffer::data, datalen, DBGC, DBGC2, free_iob(), hdr, head, IEEE80211_FC_PROTECTED, IEEE80211_TYP_FRAME_HEADER_LEN, iob_len(), iob_put, key, le32_to_cpu, memcmp(), memcpy(), mic, NULL, net80211_crypto::priv, io_buffer::tail, TKIP_FOOT_LEN, TKIP_HEAD_LEN, TKIP_MIC_LEN, tkip_michael(), tkip_mix_1(), tkip_mix_2(), u16, u32, and u8.

tkip_kie_mic()

void tkip_kie_mic ( const void * kck, const void * msg, size_t len, void * mic )

static

Calculate HMAC-MD5 MIC for EAPOL-Key frame.

Parameters

kck	Key Confirmation Key, 16 bytes
msg	Message to calculate MIC over
len	Number of bytes to calculate MIC over

Return values

mic	Calculated MIC, 16 bytes long

Definition at line 546 of file wpa_tkip.c.

{
        uint8_t ctx[MD5_CTX_SIZE + MD5_BLOCK_SIZE];
        u8 kckb[16];
 
        memcpy ( kckb, kck, sizeof ( kckb ) );
 
        hmac_init ( &md5_algorithm, ctx, kckb, sizeof ( kckb ) );
        hmac_update ( &md5_algorithm, ctx, msg, len );
        hmac_final ( &md5_algorithm, ctx, mic );
}

References ctx, hmac_final(), hmac_init(), hmac_update(), kck, len, md5_algorithm, MD5_BLOCK_SIZE, MD5_CTX_SIZE, memcpy(), mic, msg(), and u8.

tkip_kie_decrypt()

int tkip_kie_decrypt ( const void * kek, const void * iv, void * msg, u16 * len )

static

Decrypt key data in EAPOL-Key frame.

Parameters

kek	Key Encryption Key, 16 bytes
iv	Initialisation vector, 16 bytes
msg	Message to decrypt
len	Length of message

Return values

msg	Decrypted message in place of original
len	Unchanged
rc	Always 0 for success

Definition at line 570 of file wpa_tkip.c.

{
        u8 key[32];
        memcpy ( key, iv, 16 );
        memcpy ( key + 16, kek, 16 );
 
        arc4_skip ( key, 32, 256, msg, msg, *len );
 
        return 0;
}

References arc4_skip(), iv, kek, key, len, memcpy(), msg(), u16, and u8.

Variable Documentation

Sbox

const u16 Sbox[256]

static

TKIP S-box.

Definition at line 97 of file wpa_tkip.c.

                             {
        0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
        0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
        0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
        0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
        0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
        0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
        0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
        0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
        0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
        0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
        0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
        0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
        0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
        0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
        0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
        0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
        0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
        0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
        0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
        0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
        0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
        0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
        0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
        0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
        0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
        0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
        0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
        0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
        0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
        0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
        0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
        0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
};

Referenced by S().

__net80211_crypto

struct net80211_crypto tkip_crypto __net80211_crypto

Initial value:

= {
        .algorithm = NET80211_CRYPT_TKIP,
        .init = tkip_init,
        .encrypt = tkip_encrypt,
        .decrypt = tkip_decrypt,
        .priv_len = sizeof ( struct tkip_ctx ),
}

TKIP cryptosystem.

Definition at line 527 of file wpa_tkip.c.

                                                       {
        .algorithm = NET80211_CRYPT_TKIP,
        .init = tkip_init,
        .encrypt = tkip_encrypt,
        .decrypt = tkip_decrypt,
        .priv_len = sizeof ( struct tkip_ctx ),
};

__wpa_kie

struct wpa_kie tkip_kie __wpa_kie

Initial value:

= {
        .version = EAPOL_KEY_VERSION_WPA,
        .mic = tkip_kie_mic,
        .decrypt = tkip_kie_decrypt,
}

TKIP-style key integrity and encryption handler.

Definition at line 584 of file wpa_tkip.c.

                                    {
        .version = EAPOL_KEY_VERSION_WPA,
        .mic = tkip_kie_mic,
        .decrypt = tkip_kie_decrypt,
};