author | Eric Biggers <ebiggers@google.com> | 2018-09-12 03:05:10 (GMT) |
---|---|---|
committer | Eric Biggers <ebiggers@google.com> | 2018-12-13 17:34:58 (GMT) |
commit | ede5c83359740b5c8158b0c2736d7386472fb757 (patch) | |
tree | bda4fcc91487ef07e8072e88fdc6471dbf6e02f6 | |
parent | 3e5e2bc81a68c417320329837684d98374f11d9c (diff) | |
download | common-ede5c83359740b5c8158b0c2736d7386472fb757.zip common-ede5c83359740b5c8158b0c2736d7386472fb757.tar.gz common-ede5c83359740b5c8158b0c2736d7386472fb757.tar.bz2 |
BACKPORT: 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>
(cherry picked from commit a5e9f557098e54af44ade5d501379be18435bfbf)
Conflicts:
drivers/char/random.c
Bug: 112008522
Test: As series, see Ic61c13b53facfd2173065be715a7ee5f3af8760b
Change-Id: Ic355d2416330ae2f4a50cb7064633810e35a93bf
Signed-off-by: Eric Biggers <ebiggers@google.com>
-rw-r--r-- | crypto/chacha20_generic.c | 7 | ||||
-rw-r--r-- | drivers/char/random.c | 24 | ||||
-rw-r--r-- | include/crypto/chacha20.h | 3 | ||||
-rw-r--r-- | lib/chacha20.c | 6 |
4 files changed, 20 insertions, 20 deletions
diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c index 1a48d3a..94a2048 100644 --- a/crypto/chacha20_generic.c +++ b/crypto/chacha20_generic.c @@ -19,20 +19,21 @@ 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 4fc600d..d2ff213 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -440,9 +440,9 @@ 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 struct ratelimit_state unseeded_warning = @@ -868,7 +868,7 @@ 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; @@ -926,7 +926,7 @@ static inline void crng_wait_ready(void) } static void _extract_crng(struct crng_state *crng, - __u32 out[CHACHA20_BLOCK_WORDS]) + __u8 out[CHACHA20_BLOCK_SIZE]) { unsigned long v, flags; @@ -943,7 +943,7 @@ 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; @@ -961,7 +961,7 @@ 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; @@ -973,14 +973,14 @@ 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; @@ -996,7 +996,7 @@ 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) { @@ -1564,7 +1564,7 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, */ void get_random_bytes(void *buf, int nbytes) { - __u32 tmp[CHACHA20_BLOCK_WORDS]; + __u8 tmp[CHACHA20_BLOCK_SIZE] __aligned(4); #if DEBUG_RANDOM_BOOT > 0 if (!crng_ready()) @@ -2132,7 +2132,7 @@ unsigned long get_random_long(void) batch = &get_cpu_var(batched_entropy_long); if (batch->position % ARRAY_SIZE(batch->entropy_long) == 0) { - extract_crng((__u32 *)batch->entropy_long); + extract_crng((u8 *)batch->entropy_long); batch->position = 0; } ret = batch->entropy_long[batch->position++]; @@ -2158,7 +2158,7 @@ unsigned int get_random_int(void) batch = &get_cpu_var(batched_entropy_int); if (batch->position % ARRAY_SIZE(batch->entropy_int) == 0) { - extract_crng((__u32 *)batch->entropy_int); + extract_crng((u8 *)batch->entropy_int); batch->position = 0; } ret = batch->entropy_int[batch->position++]; diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h index 254298b..01543a9 100644 --- a/include/crypto/chacha20.h +++ b/include/crypto/chacha20.h @@ -11,13 +11,12 @@ #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_tfm *tfm, const u8 *key, unsigned int keysize); diff --git a/lib/chacha20.c b/lib/chacha20.c index c1cc50f..d907fec 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]++; } |