From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
commit 6c0eace6e1499712583b6ee62d95161e8b3449f5 upstream.
This gets rid of another abstraction we no longer need. It would be nice
if we could instead make pool an array rather than a pointer, but the
latent entropy plugin won't be able to do its magic in that case. So
instead we put all accesses to the input pool's actual data through the
input_pool_data array directly.
Reviewed-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/random.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -496,17 +496,12 @@ MODULE_PARM_DESC(ratelimit_disable, "Dis
static u32 input_pool_data[POOL_WORDS] __latent_entropy;
static struct {
- /* read-only data: */
- u32 *pool;
-
- /* read-write data: */
spinlock_t lock;
u16 add_ptr;
u16 input_rotate;
int entropy_count;
} input_pool = {
.lock = __SPIN_LOCK_UNLOCKED(input_pool.lock),
- .pool = input_pool_data
};
static ssize_t extract_entropy(void *buf, size_t nbytes, int min);
@@ -544,15 +539,15 @@ static void _mix_pool_bytes(const void *
i = (i - 1) & POOL_WORDMASK;
/* XOR in the various taps */
- w ^= input_pool.pool[i];
- w ^= input_pool.pool[(i + POOL_TAP1) & POOL_WORDMASK];
- w ^= input_pool.pool[(i + POOL_TAP2) & POOL_WORDMASK];
- w ^= input_pool.pool[(i + POOL_TAP3) & POOL_WORDMASK];
- w ^= input_pool.pool[(i + POOL_TAP4) & POOL_WORDMASK];
- w ^= input_pool.pool[(i + POOL_TAP5) & POOL_WORDMASK];
+ w ^= input_pool_data[i];
+ w ^= input_pool_data[(i + POOL_TAP1) & POOL_WORDMASK];
+ w ^= input_pool_data[(i + POOL_TAP2) & POOL_WORDMASK];
+ w ^= input_pool_data[(i + POOL_TAP3) & POOL_WORDMASK];
+ w ^= input_pool_data[(i + POOL_TAP4) & POOL_WORDMASK];
+ w ^= input_pool_data[(i + POOL_TAP5) & POOL_WORDMASK];
/* Mix the result back in with a twist */
- input_pool.pool[i] = (w >> 3) ^ twist_table[w & 7];
+ input_pool_data[i] = (w >> 3) ^ twist_table[w & 7];
/*
* Normally, we add 7 bits of rotation to the pool.
@@ -1369,7 +1364,7 @@ static void extract_buf(u8 *out)
/* Generate a hash across the pool */
spin_lock_irqsave(&input_pool.lock, flags);
- blake2s_update(&state, (const u8 *)input_pool.pool, POOL_BYTES);
+ blake2s_update(&state, (const u8 *)input_pool_data, POOL_BYTES);
blake2s_final(&state, hash); /* final zeros out state */
/*
