From a5e9f557098e54af44ade5d501379be18435bfbf 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 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 --- lib/chacha20.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'lib/chacha20.c') 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]++; } -- cgit