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random: early initialization of ChaCha constants

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commit 96562f2868 upstream.

Previously, the ChaCha constants for the primary pool were only
initialized in crng_initialize_primary(), called by rand_initialize().
However, some randomness is actually extracted from the primary pool
beforehand, e.g. by kmem_cache_create(). Therefore, statically
initialize the ChaCha constants for the primary pool.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <linux-crypto@vger.kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dominik Brodowski
2021-12-31 09:26:08 +01:00
committed by Chris
parent 79a2d3c173
commit bb96d3fb5d
2 changed files with 15 additions and 5 deletions
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5
drivers/char/random.c
View File

@@ -459,6 +459,10 @@ struct crng_state {
static struct crng_state primary_crng = {
.lock = __SPIN_LOCK_UNLOCKED(primary_crng.lock),
.state[0] = CHACHA_CONSTANT_EXPA,
.state[1] = CHACHA_CONSTANT_ND_3,
.state[2] = CHACHA_CONSTANT_2_BY,
.state[3] = CHACHA_CONSTANT_TE_K,
};
/*
@@ -827,7 +831,6 @@ static void numa_crng_init(void);
static void __init crng_initialize_primary(struct crng_state *crng)
{
chacha_init_consts(crng->state);
_extract_entropy(&input_pool, &crng->state[4], sizeof(__u32) * 12, 0);
if (crng_init_try_arch_early(crng) && trust_cpu && crng_init < 2) {
invalidate_batched_entropy();

15
include/crypto/chacha20.h
View File

@@ -24,12 +24,19 @@ int crypto_chacha20_setkey(struct crypto_tfm *tfm, const u8 *key,
int crypto_chacha20_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes);
enum chacha_constants { /* expand 32-byte k */
CHACHA_CONSTANT_EXPA = 0x61707865U,
CHACHA_CONSTANT_ND_3 = 0x3320646eU,
CHACHA_CONSTANT_2_BY = 0x79622d32U,
CHACHA_CONSTANT_TE_K = 0x6b206574U
};
static inline void chacha_init_consts(u32 *state)
{
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
state[2] = 0x79622d32; /* "2-by" */
state[3] = 0x6b206574; /* "te k" */
state[0] = CHACHA_CONSTANT_EXPA;
state[1] = CHACHA_CONSTANT_ND_3;
state[2] = CHACHA_CONSTANT_2_BY;
state[3] = CHACHA_CONSTANT_TE_K;
}
#endif