From: Eric Biggers ebiggers@google.com
commit 9f480faec58cd6197a007ea1dcac6b7c3daf1139 upstream.
When chacha20_block() outputs the keystream block, it uses 'u32' stores directly. However, the callers (crypto/chacha20_generic.c and drivers/char/random.c) declare the keystream buffer as a 'u8' array, which is not guaranteed to have the needed alignment.
Fix it by having both callers declare the keystream as a 'u32' array. For now this is preferable to switching over to the unaligned access macros because chacha20_block() is only being used in cases where we can easily control the alignment (stack buffers).
Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- crypto/chacha20_generic.c | 6 +++--- drivers/char/random.c | 24 ++++++++++++------------ include/crypto/chacha20.h | 3 ++- lib/chacha20.c | 2 +- 4 files changed, 18 insertions(+), 17 deletions(-)
--- a/crypto/chacha20_generic.c +++ b/crypto/chacha20_generic.c @@ -22,20 +22,20 @@ static inline u32 le32_to_cpuvp(const vo static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src, unsigned int bytes) { - u8 stream[CHACHA20_BLOCK_SIZE]; + u32 stream[CHACHA20_BLOCK_WORDS];
if (dst != src) memcpy(dst, src, bytes);
while (bytes >= CHACHA20_BLOCK_SIZE) { chacha20_block(state, stream); - crypto_xor(dst, stream, CHACHA20_BLOCK_SIZE); + crypto_xor(dst, (const u8 *)stream, CHACHA20_BLOCK_SIZE); bytes -= CHACHA20_BLOCK_SIZE; dst += CHACHA20_BLOCK_SIZE; } if (bytes) { chacha20_block(state, stream); - crypto_xor(dst, stream, bytes); + crypto_xor(dst, (const u8 *)stream, bytes); } }
--- 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, - __u8 out[CHACHA20_BLOCK_SIZE]); + __u32 out[CHACHA20_BLOCK_WORDS]); static void _crng_backtrack_protect(struct crng_state *crng, - __u8 tmp[CHACHA20_BLOCK_SIZE], int used); + __u32 tmp[CHACHA20_BLOCK_WORDS], int used); static void process_random_ready_list(void); static void _get_random_bytes(void *buf, int nbytes);
@@ -929,7 +929,7 @@ static void crng_reseed(struct crng_stat unsigned long flags; int i, num; union { - __u8 block[CHACHA20_BLOCK_SIZE]; + __u32 block[CHACHA20_BLOCK_WORDS]; __u32 key[8]; } buf;
@@ -976,7 +976,7 @@ static void crng_reseed(struct crng_stat }
static void _extract_crng(struct crng_state *crng, - __u8 out[CHACHA20_BLOCK_SIZE]) + __u32 out[CHACHA20_BLOCK_WORDS]) { unsigned long v, flags, init_time;
@@ -996,7 +996,7 @@ static void _extract_crng(struct crng_st spin_unlock_irqrestore(&crng->lock, flags); }
-static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE]) +static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS]) { _extract_crng(select_crng(), out); } @@ -1006,7 +1006,7 @@ static void extract_crng(__u8 out[CHACHA * enough) to mutate the CRNG key to provide backtracking protection. */ static void _crng_backtrack_protect(struct crng_state *crng, - __u8 tmp[CHACHA20_BLOCK_SIZE], int used) + __u32 tmp[CHACHA20_BLOCK_WORDS], int used) { unsigned long flags; __u32 *s, *d; @@ -1018,14 +1018,14 @@ static void _crng_backtrack_protect(stru used = 0; } spin_lock_irqsave(&crng->lock, flags); - s = (__u32 *) &tmp[used]; + s = &tmp[used / sizeof(__u32)]; d = &crng->state[4]; for (i=0; i < 8; i++) *d++ ^= *s++; spin_unlock_irqrestore(&crng->lock, flags); }
-static void crng_backtrack_protect(__u8 tmp[CHACHA20_BLOCK_SIZE], int used) +static void crng_backtrack_protect(__u32 tmp[CHACHA20_BLOCK_WORDS], int used) { _crng_backtrack_protect(select_crng(), tmp, used); } @@ -1033,7 +1033,7 @@ static void crng_backtrack_protect(__u8 static ssize_t extract_crng_user(void __user *buf, size_t nbytes) { ssize_t ret = 0, i = CHACHA20_BLOCK_SIZE; - __u8 tmp[CHACHA20_BLOCK_SIZE]; + __u32 tmp[CHACHA20_BLOCK_WORDS]; int large_request = (nbytes > 256);
while (nbytes) { @@ -1619,7 +1619,7 @@ static void _warn_unseeded_randomness(co */ static void _get_random_bytes(void *buf, int nbytes) { - __u8 tmp[CHACHA20_BLOCK_SIZE]; + __u32 tmp[CHACHA20_BLOCK_WORDS];
trace_get_random_bytes(nbytes, _RET_IP_);
@@ -2220,7 +2220,7 @@ u64 get_random_u64(void) batch = raw_cpu_ptr(&batched_entropy_u64); spin_lock_irqsave(&batch->batch_lock, flags); if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) { - extract_crng((u8 *)batch->entropy_u64); + extract_crng((__u32 *)batch->entropy_u64); batch->position = 0; } ret = batch->entropy_u64[batch->position++]; @@ -2244,7 +2244,7 @@ u32 get_random_u32(void) batch = raw_cpu_ptr(&batched_entropy_u32); spin_lock_irqsave(&batch->batch_lock, flags); if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) { - extract_crng((u8 *)batch->entropy_u32); + extract_crng(batch->entropy_u32); batch->position = 0; } ret = batch->entropy_u32[batch->position++]; --- a/include/crypto/chacha20.h +++ b/include/crypto/chacha20.h @@ -13,12 +13,13 @@ #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, void *stream); +void chacha20_block(u32 *state, u32 *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); --- a/lib/chacha20.c +++ b/lib/chacha20.c @@ -21,7 +21,7 @@ static inline u32 rotl32(u32 v, u8 n) return (v << n) | (v >> (sizeof(v) * 8 - n)); }
-extern void chacha20_block(u32 *state, void *stream) +void chacha20_block(u32 *state, u32 *stream) { u32 x[16], *out = stream; int i;