From patchwork Wed Sep 12 03:05:10 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 10596681 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 487BE920 for ; Wed, 12 Sep 2018 03:08:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3316A297B2 for ; Wed, 12 Sep 2018 03:08:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2400F297C3; Wed, 12 Sep 2018 03:08:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 488CA297B2 for ; Wed, 12 Sep 2018 03:08:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726082AbeILIK1 (ORCPT ); Wed, 12 Sep 2018 04:10:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:60868 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726027AbeILIK1 (ORCPT ); Wed, 12 Sep 2018 04:10:27 -0400 Received: from sol.hsd1.wa.comcast.net (c-67-185-97-198.hsd1.wa.comcast.net [67.185.97.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5934720839; Wed, 12 Sep 2018 03:08:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1536721687; bh=4mCyA0lTVn87N3HRPWHJsYGW3cE+1nZioh8EpViLIoI=; h=From:To:Cc:Subject:Date:From; b=vyRdpW7QhwtO0FLriNrHuNZVbsY9x6jHiGLRS35y2ho2VX8lckcbMHI64pOhPTt7+ 5KYQ9mKws92hOWRIlc1Vq+uzONBjoQVHARqA/rx82yJQZI6Y5Tb9CUUrEKte7xs15a jhthj+HoJ9+PvFudfCjYJXql1UJ750nOBKZC55Iw= From: Eric Biggers To: linux-crypto@vger.kernel.org, Herbert Xu Cc: Theodore Ts'o , Yann Droneaud , =?utf-8?q?Stephan_M=C3=BCller?= Subject: [PATCH] crypto: chacha20 - Fix chacha20_block() keystream alignment (again) Date: Tue, 11 Sep 2018 20:05:10 -0700 Message-Id: <20180912030510.27025-1-ebiggers@kernel.org> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Eric Biggers In commit 9f480faec58c ("crypto: chacha20 - Fix keystream alignment for chacha20_block()"), I had missed that chacha20_block() can be called directly on the buffer passed to get_random_bytes(), which can have any alignment. So, while my commit didn't break anything, it didn't fully solve the alignment problems. Revert my solution and just update chacha20_block() to use put_unaligned_le32(), so the output buffer need not be aligned. This is simpler, and on many CPUs it's the same speed. But, I kept the 'tmp' buffers in extract_crng_user() and _get_random_bytes() 4-byte aligned, since that alignment is actually needed for _crng_backtrack_protect() too. Reported-by: Stephan Müller Cc: Theodore Ts'o Signed-off-by: Eric Biggers --- crypto/chacha20_generic.c | 7 ++++--- drivers/char/random.c | 24 ++++++++++++------------ include/crypto/chacha20.h | 3 +-- lib/chacha20.c | 6 +++--- 4 files changed, 20 insertions(+), 20 deletions(-) diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c index e451c3cb6a56..3ae96587caf9 100644 --- a/crypto/chacha20_generic.c +++ b/crypto/chacha20_generic.c @@ -18,20 +18,21 @@ static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src, unsigned int bytes) { - u32 stream[CHACHA20_BLOCK_WORDS]; + /* aligned to potentially speed up crypto_xor() */ + u8 stream[CHACHA20_BLOCK_SIZE] __aligned(sizeof(long)); if (dst != src) memcpy(dst, src, bytes); while (bytes >= CHACHA20_BLOCK_SIZE) { chacha20_block(state, stream); - crypto_xor(dst, (const u8 *)stream, CHACHA20_BLOCK_SIZE); + crypto_xor(dst, stream, CHACHA20_BLOCK_SIZE); bytes -= CHACHA20_BLOCK_SIZE; dst += CHACHA20_BLOCK_SIZE; } if (bytes) { chacha20_block(state, stream); - crypto_xor(dst, (const u8 *)stream, bytes); + crypto_xor(dst, stream, bytes); } } diff --git a/drivers/char/random.c b/drivers/char/random.c index bf5f99fc36f1..d22d967c50f0 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -433,9 +433,9 @@ static int crng_init_cnt = 0; static unsigned long crng_global_init_time = 0; #define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE) static void _extract_crng(struct crng_state *crng, - __u32 out[CHACHA20_BLOCK_WORDS]); + __u8 out[CHACHA20_BLOCK_SIZE]); static void _crng_backtrack_protect(struct crng_state *crng, - __u32 tmp[CHACHA20_BLOCK_WORDS], int used); + __u8 tmp[CHACHA20_BLOCK_SIZE], int used); static void process_random_ready_list(void); static void _get_random_bytes(void *buf, int nbytes); @@ -921,7 +921,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r) unsigned long flags; int i, num; union { - __u32 block[CHACHA20_BLOCK_WORDS]; + __u8 block[CHACHA20_BLOCK_SIZE]; __u32 key[8]; } buf; @@ -968,7 +968,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r) } static void _extract_crng(struct crng_state *crng, - __u32 out[CHACHA20_BLOCK_WORDS]) + __u8 out[CHACHA20_BLOCK_SIZE]) { unsigned long v, flags; @@ -985,7 +985,7 @@ static void _extract_crng(struct crng_state *crng, spin_unlock_irqrestore(&crng->lock, flags); } -static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS]) +static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE]) { struct crng_state *crng = NULL; @@ -1003,7 +1003,7 @@ static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS]) * enough) to mutate the CRNG key to provide backtracking protection. */ static void _crng_backtrack_protect(struct crng_state *crng, - __u32 tmp[CHACHA20_BLOCK_WORDS], int used) + __u8 tmp[CHACHA20_BLOCK_SIZE], int used) { unsigned long flags; __u32 *s, *d; @@ -1015,14 +1015,14 @@ static void _crng_backtrack_protect(struct crng_state *crng, used = 0; } spin_lock_irqsave(&crng->lock, flags); - s = &tmp[used / sizeof(__u32)]; + s = (__u32 *) &tmp[used]; d = &crng->state[4]; for (i=0; i < 8; i++) *d++ ^= *s++; spin_unlock_irqrestore(&crng->lock, flags); } -static void crng_backtrack_protect(__u32 tmp[CHACHA20_BLOCK_WORDS], int used) +static void crng_backtrack_protect(__u8 tmp[CHACHA20_BLOCK_SIZE], int used) { struct crng_state *crng = NULL; @@ -1038,7 +1038,7 @@ static void crng_backtrack_protect(__u32 tmp[CHACHA20_BLOCK_WORDS], int used) static ssize_t extract_crng_user(void __user *buf, size_t nbytes) { ssize_t ret = 0, i = CHACHA20_BLOCK_SIZE; - __u32 tmp[CHACHA20_BLOCK_WORDS]; + __u8 tmp[CHACHA20_BLOCK_SIZE] __aligned(4); int large_request = (nbytes > 256); while (nbytes) { @@ -1617,7 +1617,7 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller, */ static void _get_random_bytes(void *buf, int nbytes) { - __u32 tmp[CHACHA20_BLOCK_WORDS]; + __u8 tmp[CHACHA20_BLOCK_SIZE] __aligned(4); trace_get_random_bytes(nbytes, _RET_IP_); @@ -2243,7 +2243,7 @@ u64 get_random_u64(void) if (use_lock) read_lock_irqsave(&batched_entropy_reset_lock, flags); if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) { - extract_crng((__u32 *)batch->entropy_u64); + extract_crng((u8 *)batch->entropy_u64); batch->position = 0; } ret = batch->entropy_u64[batch->position++]; @@ -2273,7 +2273,7 @@ u32 get_random_u32(void) if (use_lock) read_lock_irqsave(&batched_entropy_reset_lock, flags); if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) { - extract_crng(batch->entropy_u32); + extract_crng((u8 *)batch->entropy_u32); batch->position = 0; } ret = batch->entropy_u32[batch->position++]; diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h index b83d66073db0..f76302d99e2b 100644 --- a/include/crypto/chacha20.h +++ b/include/crypto/chacha20.h @@ -13,13 +13,12 @@ #define CHACHA20_IV_SIZE 16 #define CHACHA20_KEY_SIZE 32 #define CHACHA20_BLOCK_SIZE 64 -#define CHACHA20_BLOCK_WORDS (CHACHA20_BLOCK_SIZE / sizeof(u32)) struct chacha20_ctx { u32 key[8]; }; -void chacha20_block(u32 *state, u32 *stream); +void chacha20_block(u32 *state, u8 *stream); void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv); int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key, unsigned int keysize); diff --git a/lib/chacha20.c b/lib/chacha20.c index c1cc50fb68c9..d907fec6a9ed 100644 --- a/lib/chacha20.c +++ b/lib/chacha20.c @@ -16,9 +16,9 @@ #include #include -void chacha20_block(u32 *state, u32 *stream) +void chacha20_block(u32 *state, u8 *stream) { - u32 x[16], *out = stream; + u32 x[16]; int i; for (i = 0; i < ARRAY_SIZE(x); i++) @@ -67,7 +67,7 @@ void chacha20_block(u32 *state, u32 *stream) } for (i = 0; i < ARRAY_SIZE(x); i++) - out[i] = cpu_to_le32(x[i] + state[i]); + put_unaligned_le32(x[i] + state[i], &stream[i * sizeof(u32)]); state[12]++; }