From ad28c2ba4318e9c882647c57edd5a435edf57907 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 11 Sep 2018 20:05:10 -0700 Subject: crypto: chacha20 - Fix chacha20_block() keystream alignment (again) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit a5e9f557098e54af44ade5d501379be18435bfbf ] 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 Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- crypto/chacha20_generic.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'crypto') 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); } } -- cgit v1.2.3