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crypto: chacha20-generic - refactor to allow varying number of rounds

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In preparation for adding XChaCha12 support, rename/refactor
chacha20-generic to support different numbers of rounds.  The
justification for needing XChaCha12 support is explained in more detail
in the patch "crypto: chacha - add XChaCha12 support".

The only difference between ChaCha{8,12,20} are the number of rounds
itself; all other parts of the algorithm are the same.  Therefore,
remove the "20" from all definitions, structures, functions, files, etc.
that will be shared by all ChaCha versions.

Also make ->setkey() store the round count in the chacha_ctx (previously
chacha20_ctx).  The generic code then passes the round count through to
chacha_block().  There will be a ->setkey() function for each explicitly
allowed round count; the encrypt/decrypt functions will be the same.  I
decided not to do it the opposite way (same ->setkey() function for all
round counts, with different encrypt/decrypt functions) because that
would have required more boilerplate code in architecture-specific
implementations of ChaCha and XChaCha.

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
2018-11-16 17:26:21 -08:00
committed by Herbert Xu
parent de61d7ae5d
commit 1ca1b91794
14 changed files with 232 additions and 215 deletions
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51
drivers/char/random.c
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@@ -265,7 +265,7 @@
#include <linux/syscalls.h>
#include <linux/completion.h>
#include <linux/uuid.h>
#include <crypto/chacha20.h>
#include <crypto/chacha.h>
#include <asm/processor.h>
#include <linux/uaccess.h>
@@ -431,11 +431,10 @@ static int crng_init = 0;
#define crng_ready() (likely(crng_init > 1))
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]);
#define CRNG_INIT_CNT_THRESH (2*CHACHA_KEY_SIZE)
static void _extract_crng(struct crng_state *crng, __u8 out[CHACHA_BLOCK_SIZE]);
static void _crng_backtrack_protect(struct crng_state *crng,
__u8 tmp[CHACHA20_BLOCK_SIZE], int used);
__u8 tmp[CHACHA_BLOCK_SIZE], int used);
static void process_random_ready_list(void);
static void _get_random_bytes(void *buf, int nbytes);
@@ -863,7 +862,7 @@ static int crng_fast_load(const char *cp, size_t len)
}
p = (unsigned char *) &primary_crng.state[4];
while (len > 0 && crng_init_cnt < CRNG_INIT_CNT_THRESH) {
p[crng_init_cnt % CHACHA20_KEY_SIZE] ^= *cp;
p[crng_init_cnt % CHACHA_KEY_SIZE] ^= *cp;
cp++; crng_init_cnt++; len--;
}
spin_unlock_irqrestore(&primary_crng.lock, flags);
@@ -895,7 +894,7 @@ static int crng_slow_load(const char *cp, size_t len)
unsigned long flags;
static unsigned char lfsr = 1;
unsigned char tmp;
unsigned i, max = CHACHA20_KEY_SIZE;
unsigned i, max = CHACHA_KEY_SIZE;
const char * src_buf = cp;
char * dest_buf = (char *) &primary_crng.state[4];
@@ -913,8 +912,8 @@ static int crng_slow_load(const char *cp, size_t len)
lfsr >>= 1;
if (tmp & 1)
lfsr ^= 0xE1;
tmp = dest_buf[i % CHACHA20_KEY_SIZE];
dest_buf[i % CHACHA20_KEY_SIZE] ^= src_buf[i % len] ^ lfsr;
tmp = dest_buf[i % CHACHA_KEY_SIZE];
dest_buf[i % CHACHA_KEY_SIZE] ^= src_buf[i % len] ^ lfsr;
lfsr += (tmp << 3) | (tmp >> 5);
}
spin_unlock_irqrestore(&primary_crng.lock, flags);
@@ -926,7 +925,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
unsigned long flags;
int i, num;
union {
__u8 block[CHACHA20_BLOCK_SIZE];
__u8 block[CHACHA_BLOCK_SIZE];
__u32 key[8];
} buf;
@@ -937,7 +936,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
} else {
_extract_crng(&primary_crng, buf.block);
_crng_backtrack_protect(&primary_crng, buf.block,
CHACHA20_KEY_SIZE);
CHACHA_KEY_SIZE);
}
spin_lock_irqsave(&crng->lock, flags);
for (i = 0; i < 8; i++) {
@@ -973,7 +972,7 @@ 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])
__u8 out[CHACHA_BLOCK_SIZE])
{
unsigned long v, flags;
@@ -990,7 +989,7 @@ 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(__u8 out[CHACHA_BLOCK_SIZE])
{
struct crng_state *crng = NULL;
@@ -1008,14 +1007,14 @@ 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)
__u8 tmp[CHACHA_BLOCK_SIZE], int used)
{
unsigned long flags;
__u32 *s, *d;
int i;
used = round_up(used, sizeof(__u32));
if (used + CHACHA20_KEY_SIZE > CHACHA20_BLOCK_SIZE) {
if (used + CHACHA_KEY_SIZE > CHACHA_BLOCK_SIZE) {
extract_crng(tmp);
used = 0;
}
@@ -1027,7 +1026,7 @@ static void _crng_backtrack_protect(struct crng_state *crng,
spin_unlock_irqrestore(&crng->lock, flags);
}
static void crng_backtrack_protect(__u8 tmp[CHACHA20_BLOCK_SIZE], int used)
static void crng_backtrack_protect(__u8 tmp[CHACHA_BLOCK_SIZE], int used)
{
struct crng_state *crng = NULL;
@@ -1042,8 +1041,8 @@ 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] __aligned(4);
ssize_t ret = 0, i = CHACHA_BLOCK_SIZE;
__u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4);
int large_request = (nbytes > 256);
while (nbytes) {
@@ -1057,7 +1056,7 @@ static ssize_t extract_crng_user(void __user *buf, size_t nbytes)
}
extract_crng(tmp);
i = min_t(int, nbytes, CHACHA20_BLOCK_SIZE);
i = min_t(int, nbytes, CHACHA_BLOCK_SIZE);
if (copy_to_user(buf, tmp, i)) {
ret = -EFAULT;
break;
@@ -1622,14 +1621,14 @@ 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] __aligned(4);
__u8 tmp[CHACHA_BLOCK_SIZE] __aligned(4);
trace_get_random_bytes(nbytes, _RET_IP_);
while (nbytes >= CHACHA20_BLOCK_SIZE) {
while (nbytes >= CHACHA_BLOCK_SIZE) {
extract_crng(buf);
buf += CHACHA20_BLOCK_SIZE;
nbytes -= CHACHA20_BLOCK_SIZE;
buf += CHACHA_BLOCK_SIZE;
nbytes -= CHACHA_BLOCK_SIZE;
}
if (nbytes > 0) {
@@ -1637,7 +1636,7 @@ static void _get_random_bytes(void *buf, int nbytes)
memcpy(buf, tmp, nbytes);
crng_backtrack_protect(tmp, nbytes);
} else
crng_backtrack_protect(tmp, CHACHA20_BLOCK_SIZE);
crng_backtrack_protect(tmp, CHACHA_BLOCK_SIZE);
memzero_explicit(tmp, sizeof(tmp));
}
@@ -2208,8 +2207,8 @@ struct ctl_table random_table[] = {
struct batched_entropy {
union {
u64 entropy_u64[CHACHA20_BLOCK_SIZE / sizeof(u64)];
u32 entropy_u32[CHACHA20_BLOCK_SIZE / sizeof(u32)];
u64 entropy_u64[CHACHA_BLOCK_SIZE / sizeof(u64)];
u32 entropy_u32[CHACHA_BLOCK_SIZE / sizeof(u32)];
};
unsigned int position;
};