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mka: Support for 256-bit SAK generation

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There is already partial support of GCM-AES-256. It is possible to
enable this mode by setting 'kay->macsec_csindex = 1;' in
ieee802_1x_kay_init() function, but the generated key contained only 128
bits of data while other 128 bits are in 0.

Enables KaY to generate full 256-bit SAK from the same 128-bit CAK. Note
that this does not support 256-bit CAK or AES-CMAC-256 -based KDF.

Signed-off-by: Andrey Kartashev <andrey.kartashev@afconsult.com>
This commit is contained in:
Andrey Kartashev 2018-11-02 19:02:18 +01:00 committed by Jouni Malinen
parent c9c93e7a24
commit c1576d44a8
3 changed files with 12 additions and 9 deletions
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13
src/pae/ieee802_1x_kay.c
View file

@ -2073,12 +2073,13 @@ ieee802_1x_kay_generate_new_sak(struct ieee802_1x_mka_participant *participant)
ctx_offset += sizeof(participant->mi);
os_memcpy(context + ctx_offset, &kay->dist_kn, sizeof(kay->dist_kn));
if (key_len == 16) {
ieee802_1x_sak_128bits_aes_cmac(participant->cak.key,
context, ctx_len, key);
} else if (key_len == 32) {
ieee802_1x_sak_128bits_aes_cmac(participant->cak.key,
context, ctx_len, key);
if (key_len == 16 || key_len == 32) {
if (ieee802_1x_sak_128bits_aes_cmac(participant->cak.key,
context, ctx_len,
key, key_len)) {
wpa_printf(MSG_ERROR, "KaY: Failed to generate SAK");
goto fail;
}
} else {
wpa_printf(MSG_ERROR, "KaY: SAK Length not support");
goto fail;

5
src/pae/ieee802_1x_key.c
View file

@ -183,7 +183,8 @@ int ieee802_1x_icv_128bits_aes_cmac(const u8 *ick, const u8 *msg,
* SAK = KDF(Key, Label, KS-nonce | MI-value list | KN, SAKLength)
*/
int ieee802_1x_sak_128bits_aes_cmac(const u8 *cak, const u8 *ctx,
size_t ctx_bytes, u8 *sak)
size_t ctx_bytes, u8 *sak, size_t sak_bytes)
{
return aes_kdf_128(cak, "IEEE8021 SAK", ctx, ctx_bytes * 8, 128, sak);
return aes_kdf_128(cak, "IEEE8021 SAK", ctx, ctx_bytes * 8,
sak_bytes * 8, sak);
}

3
src/pae/ieee802_1x_key.h
View file

@ -21,6 +21,7 @@ int ieee802_1x_ick_128bits_aes_cmac(const u8 *cak, const u8 *ckn,
int ieee802_1x_icv_128bits_aes_cmac(const u8 *ick, const u8 *msg,
size_t msg_bytes, u8 *icv);
int ieee802_1x_sak_128bits_aes_cmac(const u8 *cak, const u8 *ctx,
size_t ctx_bytes, u8 *sak);
size_t ctx_bytes, u8 *sak,
size_t sak_bytes);
#endif /* IEEE802_1X_KEY_H */