[v2 PATCH 1/4] crypto: chacha20 - Export chacha20 functions without crypto API

From: Herbert Xu
Date: Tue Nov 20 2018 - 01:04:54 EST

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This patch exports the raw chacha20 functions, including the generic
as well as x86/arm accelerated versions. This allows them to be
used without going through the crypto API.

This patch also renames struct chacha20_ctx to crypto_chacha20_ctx
to avoid naming conflicts with zinc.

In order to ensure that zinc can link to the requisite functions,
this function removes the failure mode from the x86/arm accelerated
glue code so that the modules will always load, even if the hardware
is not available. In that case, the crypto API functions would not
be registered.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---

arch/arm/crypto/chacha20-neon-glue.c | 16 ++++++++++------
arch/x86/crypto/chacha20_glue.c | 16 ++++++++++------
crypto/chacha20_generic.c | 15 ++++++++-------
include/crypto/chacha20.h | 10 ++++++++--
4 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/arch/arm/crypto/chacha20-neon-glue.c b/arch/arm/crypto/chacha20-neon-glue.c
index 59a7be08e80c..fb198e11af08 100644
--- a/arch/arm/crypto/chacha20-neon-glue.c
+++ b/arch/arm/crypto/chacha20-neon-glue.c
@@ -31,7 +31,7 @@
asmlinkage void chacha20_block_xor_neon(u32 *state, u8 *dst, const u8 *src);
asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src);

-static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
+void crypto_chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
u8 buf[CHACHA20_BLOCK_SIZE];
@@ -56,11 +56,12 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
memcpy(dst, buf, bytes);
}
}
+EXPORT_SYMBOL_GPL(crypto_chacha20_doneon);

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 crypto_chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
u32 state[16];
int err;
@@ -79,8 +80,8 @@ static int chacha20_neon(struct skcipher_request *req)
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);

- chacha20_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
- nbytes);
+ crypto_chacha20_doneon(state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
kernel_neon_end();
@@ -93,7 +94,7 @@ 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 crypto_chacha20_ctx),
.base.cra_module = THIS_MODULE,

.min_keysize = CHACHA20_KEY_SIZE,
@@ -109,13 +110,16 @@ static struct skcipher_alg alg = {
static int __init chacha20_simd_mod_init(void)
{
if (!(elf_hwcap & HWCAP_NEON))
- return -ENODEV;
+ return 0;

return crypto_register_skcipher(&alg);
}

static void __exit chacha20_simd_mod_fini(void)
{
+ if (!(elf_hwcap & HWCAP_NEON))
+ return;
+
crypto_unregister_skcipher(&alg);
}

diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c
index 9fd84fe6ec09..ba66e23cd752 100644
--- a/arch/x86/crypto/chacha20_glue.c
+++ b/arch/x86/crypto/chacha20_glue.c
@@ -39,7 +39,7 @@ static unsigned int chacha20_advance(unsigned int len, unsigned int maxblocks)
return round_up(len, CHACHA20_BLOCK_SIZE) / CHACHA20_BLOCK_SIZE;
}

-static void chacha20_dosimd(u32 *state, u8 *dst, const u8 *src,
+void crypto_chacha20_dosimd(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
#ifdef CONFIG_AS_AVX2
@@ -85,11 +85,12 @@ static void chacha20_dosimd(u32 *state, u8 *dst, const u8 *src,
state[12]++;
}
}
+EXPORT_SYMBOL_GPL(crypto_chacha20_dosimd);

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 crypto_chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
u32 *state, state_buf[16 + 2] __aligned(8);
struct skcipher_walk walk;
int err;
@@ -112,8 +113,8 @@ static int chacha20_simd(struct skcipher_request *req)
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);

- chacha20_dosimd(state, walk.dst.virt.addr, walk.src.virt.addr,
- nbytes);
+ crypto_chacha20_dosimd(state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes);

err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
@@ -128,7 +129,7 @@ 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 crypto_chacha20_ctx),
.base.cra_module = THIS_MODULE,

.min_keysize = CHACHA20_KEY_SIZE,
@@ -143,7 +144,7 @@ static struct skcipher_alg alg = {
static int __init chacha20_simd_mod_init(void)
{
if (!boot_cpu_has(X86_FEATURE_SSSE3))
- return -ENODEV;
+ return 0;

#ifdef CONFIG_AS_AVX2
chacha20_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
@@ -155,6 +156,9 @@ static int __init chacha20_simd_mod_init(void)

static void __exit chacha20_simd_mod_fini(void)
{
+ if (!boot_cpu_has(X86_FEATURE_SSSE3))
+ return;
+
crypto_unregister_skcipher(&alg);
}

diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c
index 3ae96587caf9..405179c310b9 100644
--- a/crypto/chacha20_generic.c
+++ b/crypto/chacha20_generic.c
@@ -15,7 +15,7 @@
#include <crypto/internal/skcipher.h>
#include <linux/module.h>

-static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
+void crypto_chacha20_generic(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
/* aligned to potentially speed up crypto_xor() */
@@ -35,8 +35,9 @@ static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
crypto_xor(dst, stream, bytes);
}
}
+EXPORT_SYMBOL_GPL(crypto_chacha20_generic);

-void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv)
+void crypto_chacha20_init(u32 *state, struct crypto_chacha20_ctx *ctx, u8 *iv)
{
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
@@ -60,7 +61,7 @@ EXPORT_SYMBOL_GPL(crypto_chacha20_init);
int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize)
{
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct crypto_chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
int i;

if (keysize != CHACHA20_KEY_SIZE)
@@ -76,7 +77,7 @@ EXPORT_SYMBOL_GPL(crypto_chacha20_setkey);
int crypto_chacha20_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
- struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
+ struct crypto_chacha20_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
u32 state[16];
int err;
@@ -91,8 +92,8 @@ int crypto_chacha20_crypt(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);
+ crypto_chacha20_generic(state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}

@@ -105,7 +106,7 @@ static struct skcipher_alg alg = {
.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 crypto_chacha20_ctx),
.base.cra_module = THIS_MODULE,

.min_keysize = CHACHA20_KEY_SIZE,
diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h
index 2d3129442a52..0dd99c928123 100644
--- a/include/crypto/chacha20.h
+++ b/include/crypto/chacha20.h
@@ -15,14 +15,20 @@
#define CHACHA20_BLOCK_SIZE 64
#define CHACHAPOLY_IV_SIZE 12

-struct chacha20_ctx {
+struct crypto_chacha20_ctx {
u32 key[8];
};

void chacha20_block(u32 *state, u8 *stream);
-void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv);
+void crypto_chacha20_generic(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes);
+void crypto_chacha20_init(u32 *state, struct crypto_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);
+void crypto_chacha20_dosimd(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes);
+void crypto_chacha20_doneon(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes);

#endif

Next message: Herbert Xu: "[v2 PATCH 3/4] zinc: Add x86 accelerated ChaCha20"
Previous message: Dominique Martinet: "Re: [PATCH] 9p/net: put a lower bound on msize"
In reply to: Herbert Xu: "[RFC PATCH v2 0/4] Exporting existing crypto API code through zinc"
Next in thread: Herbert Xu: "[v2 PATCH 3/4] zinc: Add x86 accelerated ChaCha20"
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