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authorEric Biggers <ebiggers@google.com>2018-09-12 06:05:10 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2018-09-21 08:24:50 +0300
commita5e9f557098e54af44ade5d501379be18435bfbf (patch)
tree4410647aaa269fd9a4e304851b06f83251b12853 /lib
parent78105c7e769b8cfa4a4d59027807882b560a2634 (diff)
downloadlinux-a5e9f557098e54af44ade5d501379be18435bfbf.tar.xz
crypto: chacha20 - Fix chacha20_block() keystream alignment (again)
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 <smueller@chronox.de> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'lib')
-rw-r--r--lib/chacha20.c6
1 files changed, 3 insertions, 3 deletions
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 <asm/unaligned.h>
#include <crypto/chacha20.h>
-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]++;
}