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    Subject[RFC PATCH v2 03/12] 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
    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.

    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 other variants is introduced by this patch.

    Signed-off-by: Eric Biggers <ebiggers@google.com>
    ---
    arch/arm/crypto/chacha20-neon-glue.c | 40 +++----
    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 | 51 ++++----
    include/crypto/chacha.h | 46 ++++++++
    include/crypto/chacha20.h | 41 -------
    lib/Makefile | 2 +-
    lib/{chacha20.c => chacha.c} | 43 ++++---
    11 files changed, 227 insertions(+), 210 deletions(-)
    rename crypto/{chacha20_generic.c => chacha_generic.c} (57%)
    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 59a7be08e80ce..7386eb1c1889d 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) {
    @@ -93,14 +93,14 @@ 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/arm64/crypto/chacha20-neon-glue.c b/arch/arm64/crypto/chacha20-neon-glue.c
    index 727579c93dedb..96e0cfb8c3f5b 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 dce7c5d39c2f2..bd249f0b29dc2 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 5c207c76abf7e..7e673f7c71107 100644
    --- a/crypto/Makefile
    +++ b/crypto/Makefile
    @@ -116,7 +116,7 @@ obj-$(CONFIG_CRYPTO_KHAZAD) += khazad.o
    obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o
    obj-$(CONFIG_CRYPTO_SEED) += seed.o
    obj-$(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 600afa99941fe..573c07e6f189e 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 57%
    rename from crypto/chacha20_generic.c
    rename to crypto/chacha_generic.c
    index 07902fe37aeb8..8e25e9930c549 100644
    --- a/crypto/chacha20_generic.c
    +++ b/crypto/chacha_generic.c
    @@ -12,33 +12,33 @@

    #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)
    {
    /* aligned to potentially speed up crypto_xor() */
    - u8 stream[CHACHA20_BLOCK_SIZE] __aligned(sizeof(long));
    + u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));

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

    - while (bytes >= CHACHA20_BLOCK_SIZE) {
    - chacha20_block(state, stream);
    - crypto_xor(dst, 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, 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, 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];
    @@ -46,7 +46,7 @@ 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;
    @@ -54,15 +54,15 @@ 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" */
    @@ -81,53 +81,61 @@ 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[] = {
    {
    @@ -135,50 +143,50 @@ 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 d22d967c50f0a..5f47c4c8b9b15 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 +431,10 @@ 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);

    @@ -858,7 +857,7 @@ 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);
    @@ -890,7 +889,7 @@ 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];

    @@ -908,8 +907,8 @@ 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);
    @@ -921,7 +920,7 @@ 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;

    @@ -932,7 +931,7 @@ 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++) {
    @@ -968,7 +967,7 @@ 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;

    @@ -985,7 +984,7 @@ 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;

    @@ -1003,14 +1002,14 @@ 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;
    }
    @@ -1022,7 +1021,7 @@ 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;

    @@ -1037,8 +1036,8 @@ 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) {
    @@ -1052,7 +1051,7 @@ 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;
    @@ -1617,14 +1616,14 @@ 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) {
    @@ -1632,7 +1631,7 @@ 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));
    }

    @@ -2203,8 +2202,8 @@ 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 0000000000000..ae79e9983c72f
    --- /dev/null
    +++ b/include/crypto/chacha.h
    @@ -0,0 +1,46 @@
    +/* SPDX-License-Identifier: GPL-2.0 */
    +/*
    + * Common values and helper functions for the ChaCha and XChaCha stream ciphers.
    + *
    + * 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
    +
    +/* 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, u8 *stream, int nrounds);
    +static inline void chacha20_block(u32 *state, u8 *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 6290d997060ec..0000000000000
    --- a/include/crypto/chacha20.h
    +++ /dev/null
    @@ -1,41 +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
    -
    -/* 192-bit nonce, then 64-bit stream position */
    -#define XCHACHA20_IV_SIZE 32
    -
    -struct chacha20_ctx {
    - u32 key[8];
    -};
    -
    -void chacha20_block(u32 *state, u8 *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 ca3f7ebb900d8..9a5f0b7a48891 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 6a484e16171d1..0a2c2e5b7b84d 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, u8 *stream)
    +void chacha_block(u32 *state, u8 *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++)
    put_unaligned_le32(x[i] + state[i], &stream[i * sizeof(u32)]);

    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);
    --
    2.19.1.331.ge82ca0e54c-goog
    \
     
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