Return-Path: From: Lukasz Rymanowski To: linux-bluetooth@vger.kernel.org Cc: szymon.janc@tieto.com, Lukasz Rymanowski Subject: [PATCH 01/12] shared/crypto: Extend bt_crypto_sign_att with sign counter Date: Wed, 21 May 2014 14:44:51 +0200 Message-Id: <1400676302-13626-2-git-send-email-lukasz.rymanowski@tieto.com> In-Reply-To: <1400676302-13626-1-git-send-email-lukasz.rymanowski@tieto.com> References: <1400676302-13626-1-git-send-email-lukasz.rymanowski@tieto.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Sign counter is use in two places during att signing: 1) Shall be concatenated with siging message before sigining: BT spec 4.1, Vol[3], Part H, chapter 2.4.5 2) Shall be a part of signature send in the att packet: BT spec 4.1 Vol[3], Part C, chapter 10.4.1 With this patch, bt_crypto_sign_att returns correct signature. Note: For testing purpose it is possible to provide sign counter less then 0. --- src/shared/crypto.c | 23 ++++++++++++++++++++--- src/shared/crypto.h | 1 + unit/test-crypto.c | 2 +- 3 files changed, 22 insertions(+), 4 deletions(-) diff --git a/src/shared/crypto.c b/src/shared/crypto.c index 0aec373..03b932a 100644 --- a/src/shared/crypto.c +++ b/src/shared/crypto.c @@ -258,23 +258,33 @@ static inline void swap128(const uint8_t src[16], uint8_t dst[16]) bool bt_crypto_sign_att(struct bt_crypto *crypto, const uint8_t key[16], const uint8_t *m, uint16_t m_len, + const int32_t sign_cnt, uint8_t signature[12]) { int fd; int len; uint8_t tmp[16], out[16]; + uint16_t msg_len = m_len + sizeof(uint32_t); + uint8_t msg[msg_len]; - if (!crypto) - return false; + memset(msg, 0, msg_len); + memcpy(msg, m, m_len); + + /* Add sign_counter to the message */ + if (sign_cnt >= 0) + put_le32(sign_cnt, msg + msg_len); + else + msg_len = m_len; /* The most significant octet of key corresponds to key[0] */ swap128(key, tmp); + memcpy(signature, tmp + 4, 12); fd = alg_new(crypto->cmac_aes, tmp, 16); if (fd < 0) return false; - len = send(fd, m, m_len, 0); + len = send(fd, msg, msg_len, 0); if (len < 0) return false; @@ -283,6 +293,13 @@ bool bt_crypto_sign_att(struct bt_crypto *crypto, const uint8_t key[16], return false; /* + * If there is sign counter available it should be placed in the + * signature as specified in BT spec. 4.1 Vol[3], Part C, + * chapter 10.4.1 + */ + if (sign_cnt >= 0) + put_le32(sign_cnt, out + 8); + /* * The most significant octet of hash corresponds to out[0] - swap it. * Then truncate in most significant bit first order to a length of * 12 octets diff --git a/src/shared/crypto.h b/src/shared/crypto.h index 64faed2..f15eac7 100644 --- a/src/shared/crypto.h +++ b/src/shared/crypto.h @@ -48,4 +48,5 @@ bool bt_crypto_s1(struct bt_crypto *crypto, const uint8_t k[16], uint8_t res[16]); bool bt_crypto_sign_att(struct bt_crypto *crypto, const uint8_t key[16], const uint8_t *m, uint16_t m_len, + const int32_t sign_cnt, uint8_t signature[12]); diff --git a/unit/test-crypto.c b/unit/test-crypto.c index 8b44f4e..34828e0 100644 --- a/unit/test-crypto.c +++ b/unit/test-crypto.c @@ -139,7 +139,7 @@ static void test_sign(gconstpointer data) const struct test_data *d = data; memset(t, 0, 12); - if (!bt_crypto_sign_att(crypto, key, d->msg, d->msg_len, t)) + if (!bt_crypto_sign_att(crypto, key, d->msg, d->msg_len, -1, t)) g_assert(true); if (g_test_verbose()) { -- 1.8.4