crypto: chacha20 - Fix keystream alignment for chacha20_block()
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>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index ec42c8b..11304bb 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -431,9 +431,9 @@ static int crng_init = 0;
static int crng_init_cnt = 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);
@@ -817,7 +817,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
unsigned long flags;
int i, num;
union {
- __u8 block[CHACHA20_BLOCK_SIZE];
+ __u32 block[CHACHA20_BLOCK_WORDS];
__u32 key[8];
} buf;
@@ -851,7 +851,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
}
static void _extract_crng(struct crng_state *crng,
- __u8 out[CHACHA20_BLOCK_SIZE])
+ __u32 out[CHACHA20_BLOCK_WORDS])
{
unsigned long v, flags;
@@ -867,7 +867,7 @@ static void _extract_crng(struct crng_state *crng,
spin_unlock_irqrestore(&crng->lock, flags);
}
-static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE])
+static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS])
{
struct crng_state *crng = NULL;
@@ -885,7 +885,7 @@ static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE])
* 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;
@@ -897,14 +897,14 @@ static void _crng_backtrack_protect(struct crng_state *crng,
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)
{
struct crng_state *crng = NULL;
@@ -920,7 +920,7 @@ static void crng_backtrack_protect(__u8 tmp[CHACHA20_BLOCK_SIZE], int used)
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) {
@@ -1507,7 +1507,7 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller,
*/
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_);
@@ -2114,7 +2114,7 @@ u64 get_random_u64(void)
if (use_lock)
read_lock_irqsave(&batched_entropy_reset_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++];
@@ -2144,7 +2144,7 @@ u32 get_random_u32(void)
if (use_lock)
read_lock_irqsave(&batched_entropy_reset_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++];