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Subject[RFC PATCH 3/9] crypto: chacha20-generic - refactor to allow varying number of rounds
Date
From: Eric Biggers <ebiggers@google.com>

In preparation for adding XChaCha12 support, rename/refactor
chacha20-generic to support different numbers of rounds.

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.

To be as careful as possible, we whitelist the allowed round counts in
the low-level generic code. Currently only 20 is allowed, i.e. no
actual use of reduced-round ChaCha is introduced by this patch.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
arch/arm/crypto/chacha20-neon-glue.c | 44 +++----
arch/arm64/crypto/chacha20-neon-glue.c | 40 +++----
arch/x86/crypto/chacha20_glue.c | 52 ++++-----
crypto/Makefile | 2 +-
crypto/chacha20poly1305.c | 10 +-
.../{chacha20_generic.c => chacha_generic.c} | 110 ++++++++++--------
drivers/char/random.c | 50 ++++----
include/crypto/chacha.h | 47 ++++++++
include/crypto/chacha20.h | 42 -------
lib/Makefile | 2 +-
lib/{chacha20.c => chacha.c} | 43 ++++---
11 files changed, 230 insertions(+), 212 deletions(-)
rename crypto/{chacha20_generic.c => chacha_generic.c} (56%)
create mode 100644 include/crypto/chacha.h
delete mode 100644 include/crypto/chacha20.h
rename lib/{chacha20.c => chacha.c} (67%)

diff --git a/arch/arm/crypto/chacha20-neon-glue.c b/arch/arm/crypto/chacha20-neon-glue.c
index 59a7be08e80c..ed8dec0f1768 100644
--- a/arch/arm/crypto/chacha20-neon-glue.c
+++ b/arch/arm/crypto/chacha20-neon-glue.c
@@ -19,7 +19,7 @@
*/

#include <crypto/algapi.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -34,20 +34,20 @@ asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);
static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
- u8 buf[CHACHA20_BLOCK_SIZE];
+ u8 buf[CHACHA_BLOCK_SIZE];

- while (bytes >= CHACHA20_BLOCK_SIZE * 4) {
+ while (bytes >= CHACHA_BLOCK_SIZE * 4) {
chacha20_4block_xor_neon(state, dst, src);
- bytes -= CHACHA20_BLOCK_SIZE * 4;
- src += CHACHA20_BLOCK_SIZE * 4;
- dst += CHACHA20_BLOCK_SIZE * 4;
+ bytes -= CHACHA_BLOCK_SIZE * 4;
+ src += CHACHA_BLOCK_SIZE * 4;
+ dst += CHACHA_BLOCK_SIZE * 4;
state[12] += 4;
}
- while (bytes >= CHACHA20_BLOCK_SIZE) {
+ while (bytes >= CHACHA_BLOCK_SIZE) {
chacha20_block_xor_neon(state, dst, src);
- bytes -= CHACHA20_BLOCK_SIZE;
- src += CHACHA20_BLOCK_SIZE;
- dst += CHACHA20_BLOCK_SIZE;
+ bytes -= CHACHA_BLOCK_SIZE;
+ src += CHACHA_BLOCK_SIZE;
+ dst += CHACHA_BLOCK_SIZE;
state[12]++;
}
if (bytes) {
@@ -60,17 +60,17 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
static int chacha20_neon(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
u32 state[16];
int err;

- if (req->cryptlen <= CHACHA20_BLOCK_SIZE || !may_use_simd())
- return crypto_chacha20_crypt(req);
+ if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
+ return crypto_chacha_crypt(req);

err = skcipher_walk_virt(&walk, req, true);

- crypto_chacha20_init(state, ctx, walk.iv);
+ crypto_chacha_init(state, ctx, walk.iv);

kernel_neon_begin();
while (walk.nbytes > 0) {
@@ -93,17 +93,17 @@ static struct skcipher_alg alg = {
.base.cra_driver_name = "chacha20-neon",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct chacha20_ctx),
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,

- .min_keysize = CHACHA20_KEY_SIZE,
- .max_keysize = CHACHA20_KEY_SIZE,
- .ivsize = CHACHA20_IV_SIZE,
- .chunksize = CHACHA20_BLOCK_SIZE,
- .walksize = 4 * CHACHA20_BLOCK_SIZE,
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .walksize = 4 * CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
- .encrypt = chacha20_neon,
- .decrypt = chacha20_neon,
+ .encrypt = chacha_neon,
+ .decrypt = chacha_neon,
};

static int __init chacha20_simd_mod_init(void)
diff --git a/arch/arm64/crypto/chacha20-neon-glue.c b/arch/arm64/crypto/chacha20-neon-glue.c
index 727579c93ded..96e0cfb8c3f5 100644
--- a/arch/arm64/crypto/chacha20-neon-glue.c
+++ b/arch/arm64/crypto/chacha20-neon-glue.c
@@ -19,7 +19,7 @@
*/

#include <crypto/algapi.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -34,15 +34,15 @@ asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);
static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
- u8 buf[CHACHA20_BLOCK_SIZE];
+ u8 buf[CHACHA_BLOCK_SIZE];

- while (bytes >= CHACHA20_BLOCK_SIZE * 4) {
+ while (bytes >= CHACHA_BLOCK_SIZE * 4) {
kernel_neon_begin();
chacha20_4block_xor_neon(state, dst, src);
kernel_neon_end();
- bytes -= CHACHA20_BLOCK_SIZE * 4;
- src += CHACHA20_BLOCK_SIZE * 4;
- dst += CHACHA20_BLOCK_SIZE * 4;
+ bytes -= CHACHA_BLOCK_SIZE * 4;
+ src += CHACHA_BLOCK_SIZE * 4;
+ dst += CHACHA_BLOCK_SIZE * 4;
state[12] += 4;
}

@@ -50,11 +50,11 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
return;

kernel_neon_begin();
- while (bytes >= CHACHA20_BLOCK_SIZE) {
+ while (bytes >= CHACHA_BLOCK_SIZE) {
chacha20_block_xor_neon(state, dst, src);
- bytes -= CHACHA20_BLOCK_SIZE;
- src += CHACHA20_BLOCK_SIZE;
- dst += CHACHA20_BLOCK_SIZE;
+ bytes -= CHACHA_BLOCK_SIZE;
+ src += CHACHA_BLOCK_SIZE;
+ dst += CHACHA_BLOCK_SIZE;
state[12]++;
}
if (bytes) {
@@ -68,17 +68,17 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
static int chacha20_neon(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
u32 state[16];
int err;

- if (!may_use_simd() || req->cryptlen <= CHACHA20_BLOCK_SIZE)
- return crypto_chacha20_crypt(req);
+ if (!may_use_simd() || req->cryptlen <= CHACHA_BLOCK_SIZE)
+ return crypto_chacha_crypt(req);

err = skcipher_walk_virt(&walk, req, false);

- crypto_chacha20_init(state, ctx, walk.iv);
+ crypto_chacha_init(state, ctx, walk.iv);

while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
@@ -99,14 +99,14 @@ static struct skcipher_alg alg = {
.base.cra_driver_name = "chacha20-neon",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct chacha20_ctx),
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,

- .min_keysize = CHACHA20_KEY_SIZE,
- .max_keysize = CHACHA20_KEY_SIZE,
- .ivsize = CHACHA20_IV_SIZE,
- .chunksize = CHACHA20_BLOCK_SIZE,
- .walksize = 4 * CHACHA20_BLOCK_SIZE,
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .walksize = 4 * CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
.encrypt = chacha20_neon,
.decrypt = chacha20_neon,
diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c
index dce7c5d39c2f..bd249f0b29dc 100644
--- a/arch/x86/crypto/chacha20_glue.c
+++ b/arch/x86/crypto/chacha20_glue.c
@@ -10,7 +10,7 @@
*/

#include <crypto/algapi.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -29,31 +29,31 @@ static bool chacha20_use_avx2;
static void chacha20_dosimd(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
- u8 buf[CHACHA20_BLOCK_SIZE];
+ u8 buf[CHACHA_BLOCK_SIZE];

#ifdef CONFIG_AS_AVX2
if (chacha20_use_avx2) {
- while (bytes >= CHACHA20_BLOCK_SIZE * 8) {
+ while (bytes >= CHACHA_BLOCK_SIZE * 8) {
chacha20_8block_xor_avx2(state, dst, src);
- bytes -= CHACHA20_BLOCK_SIZE * 8;
- src += CHACHA20_BLOCK_SIZE * 8;
- dst += CHACHA20_BLOCK_SIZE * 8;
+ bytes -= CHACHA_BLOCK_SIZE * 8;
+ src += CHACHA_BLOCK_SIZE * 8;
+ dst += CHACHA_BLOCK_SIZE * 8;
state[12] += 8;
}
}
#endif
- while (bytes >= CHACHA20_BLOCK_SIZE * 4) {
+ while (bytes >= CHACHA_BLOCK_SIZE * 4) {
chacha20_4block_xor_ssse3(state, dst, src);
- bytes -= CHACHA20_BLOCK_SIZE * 4;
- src += CHACHA20_BLOCK_SIZE * 4;
- dst += CHACHA20_BLOCK_SIZE * 4;
+ bytes -= CHACHA_BLOCK_SIZE * 4;
+ src += CHACHA_BLOCK_SIZE * 4;
+ dst += CHACHA_BLOCK_SIZE * 4;
state[12] += 4;
}
- while (bytes >= CHACHA20_BLOCK_SIZE) {
+ while (bytes >= CHACHA_BLOCK_SIZE) {
chacha20_block_xor_ssse3(state, dst, src);
- bytes -= CHACHA20_BLOCK_SIZE;
- src += CHACHA20_BLOCK_SIZE;
- dst += CHACHA20_BLOCK_SIZE;
+ bytes -= CHACHA_BLOCK_SIZE;
+ src += CHACHA_BLOCK_SIZE;
+ dst += CHACHA_BLOCK_SIZE;
state[12]++;
}
if (bytes) {
@@ -66,7 +66,7 @@ static void chacha20_dosimd(u32 *state, u8 *dst, const u8 *src,
static int chacha20_simd(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
u32 *state, state_buf[16 + 2] __aligned(8);
struct skcipher_walk walk;
int err;
@@ -74,20 +74,20 @@ static int chacha20_simd(struct skcipher_request *req)
BUILD_BUG_ON(CHACHA20_STATE_ALIGN != 16);
state = PTR_ALIGN(state_buf + 0, CHACHA20_STATE_ALIGN);

- if (req->cryptlen <= CHACHA20_BLOCK_SIZE || !may_use_simd())
- return crypto_chacha20_crypt(req);
+ if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd())
+ return crypto_chacha_crypt(req);

err = skcipher_walk_virt(&walk, req, true);

- crypto_chacha20_init(state, ctx, walk.iv);
+ crypto_chacha_init(state, ctx, walk.iv);

kernel_fpu_begin();

- while (walk.nbytes >= CHACHA20_BLOCK_SIZE) {
+ while (walk.nbytes >= CHACHA_BLOCK_SIZE) {
chacha20_dosimd(state, walk.dst.virt.addr, walk.src.virt.addr,
- rounddown(walk.nbytes, CHACHA20_BLOCK_SIZE));
+ rounddown(walk.nbytes, CHACHA_BLOCK_SIZE));
err = skcipher_walk_done(&walk,
- walk.nbytes % CHACHA20_BLOCK_SIZE);
+ walk.nbytes % CHACHA_BLOCK_SIZE);
}

if (walk.nbytes) {
@@ -106,13 +106,13 @@ static struct skcipher_alg alg = {
.base.cra_driver_name = "chacha20-simd",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct chacha20_ctx),
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,

- .min_keysize = CHACHA20_KEY_SIZE,
- .max_keysize = CHACHA20_KEY_SIZE,
- .ivsize = CHACHA20_IV_SIZE,
- .chunksize = CHACHA20_BLOCK_SIZE,
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
.encrypt = chacha20_simd,
.decrypt = chacha20_simd,
diff --git a/crypto/Makefile b/crypto/Makefile
index 6d1d40eeb964..0701c4577dc6 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -117,7 +117,7 @@ obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o
obj-$(CONFIG_CRYPTO_SEED) += seed.o
obj-$(CONFIG_CRYPTO_SPECK) += speck.o
obj-$(CONFIG_CRYPTO_SALSA20) += salsa20_generic.o
-obj-$(CONFIG_CRYPTO_CHACHA20) += chacha20_generic.o
+obj-$(CONFIG_CRYPTO_CHACHA20) += chacha_generic.o
obj-$(CONFIG_CRYPTO_POLY1305) += poly1305_generic.o
obj-$(CONFIG_CRYPTO_DEFLATE) += deflate.o
obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
diff --git a/crypto/chacha20poly1305.c b/crypto/chacha20poly1305.c
index 600afa99941f..573c07e6f189 100644
--- a/crypto/chacha20poly1305.c
+++ b/crypto/chacha20poly1305.c
@@ -13,7 +13,7 @@
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>
#include <crypto/poly1305.h>
#include <linux/err.h>
#include <linux/init.h>
@@ -51,7 +51,7 @@ struct poly_req {
};

struct chacha_req {
- u8 iv[CHACHA20_IV_SIZE];
+ u8 iv[CHACHA_IV_SIZE];
struct scatterlist src[1];
struct skcipher_request req; /* must be last member */
};
@@ -91,7 +91,7 @@ static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
memcpy(iv, &leicb, sizeof(leicb));
memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
- CHACHA20_IV_SIZE - sizeof(leicb) - ctx->saltlen);
+ CHACHA_IV_SIZE - sizeof(leicb) - ctx->saltlen);
}

static int poly_verify_tag(struct aead_request *req)
@@ -494,7 +494,7 @@ static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
int err;

- if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
+ if (keylen != ctx->saltlen + CHACHA_KEY_SIZE)
return -EINVAL;

keylen -= ctx->saltlen;
@@ -639,7 +639,7 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,

err = -EINVAL;
/* Need 16-byte IV size, including Initial Block Counter value */
- if (crypto_skcipher_alg_ivsize(chacha) != CHACHA20_IV_SIZE)
+ if (crypto_skcipher_alg_ivsize(chacha) != CHACHA_IV_SIZE)
goto out_drop_chacha;
/* Not a stream cipher? */
if (chacha->base.cra_blocksize != 1)
diff --git a/crypto/chacha20_generic.c b/crypto/chacha_generic.c
similarity index 56%
rename from crypto/chacha20_generic.c
rename to crypto/chacha_generic.c
index ba97aac93912..46496997847a 100644
--- a/crypto/chacha20_generic.c
+++ b/crypto/chacha_generic.c
@@ -12,32 +12,32 @@

#include <asm/unaligned.h>
#include <crypto/algapi.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/module.h>

-static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
- unsigned int bytes)
+static void chacha_docrypt(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes, int nrounds)
{
- u32 stream[CHACHA20_BLOCK_WORDS];
+ u32 stream[CHACHA_BLOCK_WORDS];

if (dst != src)
memcpy(dst, src, bytes);

- while (bytes >= CHACHA20_BLOCK_SIZE) {
- chacha20_block(state, stream);
- crypto_xor(dst, (const u8 *)stream, CHACHA20_BLOCK_SIZE);
- bytes -= CHACHA20_BLOCK_SIZE;
- dst += CHACHA20_BLOCK_SIZE;
+ while (bytes >= CHACHA_BLOCK_SIZE) {
+ chacha_block(state, stream, nrounds);
+ crypto_xor(dst, (const u8 *)stream, CHACHA_BLOCK_SIZE);
+ bytes -= CHACHA_BLOCK_SIZE;
+ dst += CHACHA_BLOCK_SIZE;
}
if (bytes) {
- chacha20_block(state, stream);
+ chacha_block(state, stream, nrounds);
crypto_xor(dst, (const u8 *)stream, bytes);
}
}

-static int chacha20_stream_xor(struct skcipher_request *req,
- struct chacha20_ctx *ctx, u8 *iv)
+static int chacha_stream_xor(struct skcipher_request *req,
+ struct chacha_ctx *ctx, u8 *iv)
{
struct skcipher_walk walk;
u32 state[16];
@@ -45,7 +45,7 @@ static int chacha20_stream_xor(struct skcipher_request *req,

err = skcipher_walk_virt(&walk, req, true);

- crypto_chacha20_init(state, ctx, iv);
+ crypto_chacha_init(state, ctx, iv);

while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
@@ -53,15 +53,15 @@ static int chacha20_stream_xor(struct skcipher_request *req,
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);

- chacha20_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
- nbytes);
+ chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
+ nbytes, ctx->nrounds);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}

return err;
}

-void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv)
+void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv)
{
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
@@ -80,53 +80,61 @@ void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv)
state[14] = get_unaligned_le32(iv + 8);
state[15] = get_unaligned_le32(iv + 12);
}
-EXPORT_SYMBOL_GPL(crypto_chacha20_init);
+EXPORT_SYMBOL_GPL(crypto_chacha_init);

-int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
- unsigned int keysize)
+static int chacha_setkey(struct crypto_skcipher *tfm, const u8 *key,
+ unsigned int keysize, int nrounds)
{
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
int i;

- if (keysize != CHACHA20_KEY_SIZE)
+ if (keysize != CHACHA_KEY_SIZE)
return -EINVAL;

for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));

+ ctx->nrounds = nrounds;
return 0;
}
+
+int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+ unsigned int keysize)
+{
+ return chacha_setkey(tfm, key, keysize, 20);
+}
EXPORT_SYMBOL_GPL(crypto_chacha20_setkey);

-int crypto_chacha20_crypt(struct skcipher_request *req)
+int crypto_chacha_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);

- return chacha20_stream_xor(req, ctx, req->iv);
+ return chacha_stream_xor(req, ctx, req->iv);
}
-EXPORT_SYMBOL_GPL(crypto_chacha20_crypt);
+EXPORT_SYMBOL_GPL(crypto_chacha_crypt);

-int crypto_xchacha20_crypt(struct skcipher_request *req)
+int crypto_xchacha_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
- struct chacha20_ctx subctx;
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct chacha_ctx subctx;
u32 state[16];
u8 real_iv[16];

/* Compute the subkey given the original key and first 128 nonce bits */
- crypto_chacha20_init(state, ctx, req->iv);
- hchacha20_block(state, subctx.key);
+ crypto_chacha_init(state, ctx, req->iv);
+ hchacha_block(state, subctx.key, ctx->nrounds);
+ subctx.nrounds = ctx->nrounds;

/* Build the real IV */
memcpy(&real_iv[0], req->iv + 24, 8); /* stream position */
memcpy(&real_iv[8], req->iv + 16, 8); /* remaining 64 nonce bits */

/* Generate the stream and XOR it with the data */
- return chacha20_stream_xor(req, &subctx, real_iv);
+ return chacha_stream_xor(req, &subctx, real_iv);
}
-EXPORT_SYMBOL_GPL(crypto_xchacha20_crypt);
+EXPORT_SYMBOL_GPL(crypto_xchacha_crypt);

static struct skcipher_alg algs[] = {
{
@@ -134,50 +142,50 @@ static struct skcipher_alg algs[] = {
.base.cra_driver_name = "chacha20-generic",
.base.cra_priority = 100,
.base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct chacha20_ctx),
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,

- .min_keysize = CHACHA20_KEY_SIZE,
- .max_keysize = CHACHA20_KEY_SIZE,
- .ivsize = CHACHA20_IV_SIZE,
- .chunksize = CHACHA20_BLOCK_SIZE,
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
- .encrypt = crypto_chacha20_crypt,
- .decrypt = crypto_chacha20_crypt,
+ .encrypt = crypto_chacha_crypt,
+ .decrypt = crypto_chacha_crypt,
}, {
.base.cra_name = "xchacha20",
.base.cra_driver_name = "xchacha20-generic",
.base.cra_priority = 100,
.base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct chacha20_ctx),
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,

- .min_keysize = CHACHA20_KEY_SIZE,
- .max_keysize = CHACHA20_KEY_SIZE,
- .ivsize = XCHACHA20_IV_SIZE,
- .chunksize = CHACHA20_BLOCK_SIZE,
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = XCHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
- .encrypt = crypto_xchacha20_crypt,
- .decrypt = crypto_xchacha20_crypt,
+ .encrypt = crypto_xchacha_crypt,
+ .decrypt = crypto_xchacha_crypt,
}
};

-static int __init chacha20_generic_mod_init(void)
+static int __init chacha_generic_mod_init(void)
{
return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
}

-static void __exit chacha20_generic_mod_fini(void)
+static void __exit chacha_generic_mod_fini(void)
{
crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
}

-module_init(chacha20_generic_mod_init);
-module_exit(chacha20_generic_mod_fini);
+module_init(chacha_generic_mod_init);
+module_exit(chacha_generic_mod_fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
-MODULE_DESCRIPTION("ChaCha20 and XChaCha20 stream ciphers (generic)");
+MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (generic)");
MODULE_ALIAS_CRYPTO("chacha20");
MODULE_ALIAS_CRYPTO("chacha20-generic");
MODULE_ALIAS_CRYPTO("xchacha20");
diff --git a/drivers/char/random.c b/drivers/char/random.c
index bd449ad52442..edf956084179 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -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 +431,11 @@ 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)
+#define CRNG_INIT_CNT_THRESH (2*CHACHA_KEY_SIZE)
static void _extract_crng(struct crng_state *crng,
- __u32 out[CHACHA20_BLOCK_WORDS]);
+ __u32 out[CHACHA_BLOCK_WORDS]);
static void _crng_backtrack_protect(struct crng_state *crng,
- __u32 tmp[CHACHA20_BLOCK_WORDS], int used);
+ __u32 tmp[CHACHA_BLOCK_WORDS], int used);
static void process_random_ready_list(void);
static void _get_random_bytes(void *buf, int nbytes);

@@ -849,7 +849,7 @@ 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);
@@ -881,7 +881,7 @@ 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];

@@ -899,8 +899,8 @@ 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);
@@ -912,7 +912,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
unsigned long flags;
int i, num;
union {
- __u32 block[CHACHA20_BLOCK_WORDS];
+ __u32 block[CHACHA_BLOCK_WORDS];
__u32 key[8];
} buf;

@@ -923,7 +923,7 @@ 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++) {
@@ -959,7 +959,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
}

static void _extract_crng(struct crng_state *crng,
- __u32 out[CHACHA20_BLOCK_WORDS])
+ __u32 out[CHACHA_BLOCK_WORDS])
{
unsigned long v, flags;

@@ -976,7 +976,7 @@ static void _extract_crng(struct crng_state *crng,
spin_unlock_irqrestore(&crng->lock, flags);
}

-static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS])
+static void extract_crng(__u32 out[CHACHA_BLOCK_WORDS])
{
struct crng_state *crng = NULL;

@@ -994,14 +994,14 @@ static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS])
* enough) to mutate the CRNG key to provide backtracking protection.
*/
static void _crng_backtrack_protect(struct crng_state *crng,
- __u32 tmp[CHACHA20_BLOCK_WORDS], int used)
+ __u32 tmp[CHACHA_BLOCK_WORDS], 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;
}
@@ -1013,7 +1013,7 @@ static void _crng_backtrack_protect(struct crng_state *crng,
spin_unlock_irqrestore(&crng->lock, flags);
}

-static void crng_backtrack_protect(__u32 tmp[CHACHA20_BLOCK_WORDS], int used)
+static void crng_backtrack_protect(__u32 tmp[CHACHA_BLOCK_WORDS], int used)
{
struct crng_state *crng = NULL;

@@ -1028,8 +1028,8 @@ static void crng_backtrack_protect(__u32 tmp[CHACHA20_BLOCK_WORDS], int used)

static ssize_t extract_crng_user(void __user *buf, size_t nbytes)
{
- ssize_t ret = 0, i = CHACHA20_BLOCK_SIZE;
- __u32 tmp[CHACHA20_BLOCK_WORDS];
+ ssize_t ret = 0, i = CHACHA_BLOCK_SIZE;
+ __u32 tmp[CHACHA_BLOCK_WORDS];
int large_request = (nbytes > 256);

while (nbytes) {
@@ -1043,7 +1043,7 @@ 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;
@@ -1612,14 +1612,14 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller,
*/
static void _get_random_bytes(void *buf, int nbytes)
{
- __u32 tmp[CHACHA20_BLOCK_WORDS];
+ __u32 tmp[CHACHA_BLOCK_WORDS];

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) {
@@ -1627,7 +1627,7 @@ 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));
}

@@ -2182,8 +2182,8 @@ 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;
};
diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h
new file mode 100644
index 000000000000..a504350f54df
--- /dev/null
+++ b/include/crypto/chacha.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common values and helper functions for the ChaCha and XChaCha algorithms.
+ *
+ * XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's
+ * security. Here they share the same key size, tfm context, and setkey
+ * function; only their IV size and encrypt/decrypt function differ.
+ */
+
+#ifndef _CRYPTO_CHACHA_H
+#define _CRYPTO_CHACHA_H
+
+#include <crypto/skcipher.h>
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
+#define CHACHA_IV_SIZE 16
+
+#define CHACHA_KEY_SIZE 32
+#define CHACHA_BLOCK_SIZE 64
+#define CHACHA_BLOCK_WORDS (CHACHA_BLOCK_SIZE / sizeof(u32))
+
+/* 192-bit nonce, then 64-bit stream position */
+#define XCHACHA_IV_SIZE 32
+
+struct chacha_ctx {
+ u32 key[8];
+ int nrounds;
+};
+
+void chacha_block(u32 *state, u32 *stream, int nrounds);
+static inline void chacha20_block(u32 *state, u32 *stream)
+{
+ chacha_block(state, stream, 20);
+}
+void hchacha_block(const u32 *in, u32 *out, int nrounds);
+
+void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv);
+
+int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+ unsigned int keysize);
+
+int crypto_chacha_crypt(struct skcipher_request *req);
+int crypto_xchacha_crypt(struct skcipher_request *req);
+
+#endif /* _CRYPTO_CHACHA_H */
diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h
deleted file mode 100644
index f977e685925d..000000000000
--- a/include/crypto/chacha20.h
+++ /dev/null
@@ -1,42 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Common values and helper functions for the ChaCha20 and XChaCha20 algorithms.
- *
- * XChaCha20 extends ChaCha20's nonce to 192 bits, while provably retaining
- * ChaCha20's security. Here they share the same key size, tfm context, and
- * setkey function; only their IV size and encrypt/decrypt function differ.
- */
-
-#ifndef _CRYPTO_CHACHA20_H
-#define _CRYPTO_CHACHA20_H
-
-#include <crypto/skcipher.h>
-#include <linux/types.h>
-#include <linux/crypto.h>
-
-/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
-#define CHACHA20_IV_SIZE 16
-
-#define CHACHA20_KEY_SIZE 32
-#define CHACHA20_BLOCK_SIZE 64
-#define CHACHA20_BLOCK_WORDS (CHACHA20_BLOCK_SIZE / sizeof(u32))
-
-/* 192-bit nonce, then 64-bit stream position */
-#define XCHACHA20_IV_SIZE 32
-
-struct chacha20_ctx {
- u32 key[8];
-};
-
-void chacha20_block(u32 *state, u32 *stream);
-void hchacha20_block(const u32 *in, u32 *out);
-
-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);
-
-int crypto_chacha20_crypt(struct skcipher_request *req);
-int crypto_xchacha20_crypt(struct skcipher_request *req);
-
-#endif
diff --git a/lib/Makefile b/lib/Makefile
index 90dc5520b784..e37f0f922185 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -20,7 +20,7 @@ KCOV_INSTRUMENT_dynamic_debug.o := n
lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o timerqueue.o\
idr.o int_sqrt.o extable.o \
- sha1.o chacha20.o irq_regs.o argv_split.o \
+ sha1.o chacha.o irq_regs.o argv_split.o \
flex_proportions.o ratelimit.o show_mem.o \
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
diff --git a/lib/chacha20.c b/lib/chacha.c
similarity index 67%
rename from lib/chacha20.c
rename to lib/chacha.c
index 13a0bdcb1604..b0fd1e0882e3 100644
--- a/lib/chacha20.c
+++ b/lib/chacha.c
@@ -1,5 +1,5 @@
/*
- * The "hash function" used as the core of the ChaCha20 stream cipher (RFC7539)
+ * The "hash function" used as the core of the ChaCha stream cipher (RFC7539)
*
* Copyright (C) 2015 Martin Willi
*
@@ -14,13 +14,16 @@
#include <linux/bitops.h>
#include <linux/cryptohash.h>
#include <asm/unaligned.h>
-#include <crypto/chacha20.h>
+#include <crypto/chacha.h>

-static void chacha20_permute(u32 *x)
+static void chacha_permute(u32 *x, int nrounds)
{
int i;

- for (i = 0; i < 20; i += 2) {
+ /* whitelist the allowed round counts */
+ BUG_ON(nrounds != 20);
+
+ for (i = 0; i < nrounds; i += 2) {
x[0] += x[4]; x[12] = rol32(x[12] ^ x[0], 16);
x[1] += x[5]; x[13] = rol32(x[13] ^ x[1], 16);
x[2] += x[6]; x[14] = rol32(x[14] ^ x[2], 16);
@@ -64,49 +67,51 @@ static void chacha20_permute(u32 *x)
}

/**
- * chacha20_block - generate one keystream block and increment block counter
+ * chacha_block - generate one keystream block and increment block counter
* @state: input state matrix (16 32-bit words)
* @stream: output keystream block (64 bytes)
+ * @nrounds: number of rounds (currently must be 20)
*
- * This is the ChaCha20 core, a function from 64-byte strings to 64-byte
- * strings. The caller has already converted the endianness of the input. This
- * function also handles incrementing the block counter in the input matrix.
+ * This is the ChaCha core, a function from 64-byte strings to 64-byte strings.
+ * The caller has already converted the endianness of the input. This function
+ * also handles incrementing the block counter in the input matrix.
*/
-void chacha20_block(u32 *state, u32 *stream)
+void chacha_block(u32 *state, u32 *stream, int nrounds)
{
u32 x[16];
int i;

memcpy(x, state, 64);

- chacha20_permute(x);
+ chacha_permute(x, nrounds);

for (i = 0; i < ARRAY_SIZE(x); i++)
stream[i] = cpu_to_le32(x[i] + state[i]);

state[12]++;
}
-EXPORT_SYMBOL(chacha20_block);
+EXPORT_SYMBOL(chacha_block);

/**
- * hchacha20_block - abbreviated ChaCha20 core, for XChaCha20
+ * hchacha_block - abbreviated ChaCha core, for XChaCha
* @in: input state matrix (16 32-bit words)
* @out: output (8 32-bit words)
+ * @nrounds: number of rounds (currently must be 20)
*
- * HChaCha20 is the ChaCha equivalent of HSalsa20 and is an intermediate step
- * towards XChaCha20 (see https://cr.yp.to/snuffle/xsalsa-20081128.pdf).
- * HChaCha20 skips the final addition of the initial state, and outputs only
- * certain words of the state. It should not be used for streaming directly.
+ * HChaCha is the ChaCha equivalent of HSalsa and is an intermediate step
+ * towards XChaCha (see https://cr.yp.to/snuffle/xsalsa-20081128.pdf). HChaCha
+ * skips the final addition of the initial state, and outputs only certain words
+ * of the state. It should not be used for streaming directly.
*/
-void hchacha20_block(const u32 *in, u32 *out)
+void hchacha_block(const u32 *in, u32 *out, int nrounds)
{
u32 x[16];

memcpy(x, in, 64);

- chacha20_permute(x);
+ chacha_permute(x, nrounds);

memcpy(&out[0], &x[0], 16);
memcpy(&out[4], &x[12], 16);
}
-EXPORT_SYMBOL(hchacha20_block);
+EXPORT_SYMBOL(hchacha_block);
--
2.18.0.597.ga71716f1ad-goog
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