Re: [PATCH v2 13/14] crypto: sun8i-ce: Add support for the PRNG

LABBE Corentin
2020-04-27T08:41:45Z

On Fri, Apr 24, 2020 at 04:38:31PM +0200, Stephan Mueller wrote:
> Am Freitag, 24. April 2020, 16:02:13 CEST schrieb Corentin Labbe:
>
> Hi Corentin,
>
> > This patch had support for the PRNG present in the CE.
> > The output was tested with rngtest without any failure.
> >
> > Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
> > ---
> > drivers/crypto/allwinner/Kconfig | 8 +
> > drivers/crypto/allwinner/sun8i-ce/Makefile | 1 +
> > .../crypto/allwinner/sun8i-ce/sun8i-ce-core.c | 58 +++++-
> > .../crypto/allwinner/sun8i-ce/sun8i-ce-prng.c | 189 ++++++++++++++++++
> > drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h | 31 +++
> > 5 files changed, 286 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/crypto/allwinner/sun8i-ce/sun8i-ce-prng.c
> >
> > diff --git a/drivers/crypto/allwinner/Kconfig
> > b/drivers/crypto/allwinner/Kconfig index 93cc67adb1ed..223a5823867c 100644
> > --- a/drivers/crypto/allwinner/Kconfig
> > +++ b/drivers/crypto/allwinner/Kconfig
> > @@ -79,6 +79,14 @@ config CRYPTO_DEV_SUN8I_CE_HASH
> > help
> > Say y to enable support for hash algorithms.
> >
> > +config CRYPTO_DEV_SUN8I_CE_PRNG
> > + bool "Support for Allwinner Crypto Engine PRNG"
> > + depends on CRYPTO_DEV_SUN8I_CE
> > + select CRYPTO_RNG
> > + help
> > + Select this option if you want to provide kernel-side support for
> > + the Pseudo-Random Number Generator found in the Crypto Engine.
> > +
> > config CRYPTO_DEV_SUN8I_SS
> > tristate "Support for Allwinner Security System cryptographic
> offloader"
> > select CRYPTO_SKCIPHER
> > diff --git a/drivers/crypto/allwinner/sun8i-ce/Makefile
> > b/drivers/crypto/allwinner/sun8i-ce/Makefile index
> > d1b1f0e86c79..c0ea81da2c7d 100644
> > --- a/drivers/crypto/allwinner/sun8i-ce/Makefile
> > +++ b/drivers/crypto/allwinner/sun8i-ce/Makefile
> > @@ -1,3 +1,4 @@
> > obj-$(CONFIG_CRYPTO_DEV_SUN8I_CE) += sun8i-ce.o
> > sun8i-ce-y += sun8i-ce-core.o sun8i-ce-cipher.o
> > sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_HASH) += sun8i-ce-hash.o
> > +sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_PRNG) += sun8i-ce-prng.o
> > diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
> > b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c index
> > 8c94ffe1efd0..23b9fc67d7ea 100644
> > --- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
> > +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
> > @@ -22,6 +22,7 @@
> > #include <linux/platform_device.h>
> > #include <linux/pm_runtime.h>
> > #include <linux/reset.h>
> > +#include <crypto/internal/rng.h>
> > #include <crypto/internal/skcipher.h>
> >
> > #include "sun8i-ce.h"
> > @@ -45,6 +46,7 @@ static const struct ce_variant ce_h3_variant = {
> > { "mod", 50000000, 0 },
> > },
> > .esr = ESR_H3,
> > + .prng = CE_ALG_PRNG,
> > };
> >
> > static const struct ce_variant ce_h5_variant = {
> > @@ -60,6 +62,7 @@ static const struct ce_variant ce_h5_variant = {
> > { "mod", 300000000, 0 },
> > },
> > .esr = ESR_H5,
> > + .prng = CE_ALG_PRNG,
> > };
> >
> > static const struct ce_variant ce_h6_variant = {
> > @@ -72,12 +75,14 @@ static const struct ce_variant ce_h6_variant = {
> > },
> > .cipher_t_dlen_in_bytes = true,
> > .hash_t_dlen_in_bits = true,
> > + .prng_t_dlen_in_bytes = true,
> > .ce_clks = {
> > { "bus", 0, 200000000 },
> > { "mod", 300000000, 0 },
> > { "ram", 0, 400000000 },
> > },
> > .esr = ESR_H6,
> > + .prng = CE_ALG_PRNG_V2,
> > };
> >
> > static const struct ce_variant ce_a64_variant = {
> > @@ -93,6 +98,7 @@ static const struct ce_variant ce_a64_variant = {
> > { "mod", 300000000, 0 },
> > },
> > .esr = ESR_A64,
> > + .prng = CE_ALG_PRNG,
> > };
> >
> > static const struct ce_variant ce_r40_variant = {
> > @@ -108,15 +114,17 @@ static const struct ce_variant ce_r40_variant = {
> > { "mod", 300000000, 0 },
> > },
> > .esr = ESR_R40,
> > + .prng = CE_ALG_PRNG,
> > };
> >
> > /*
> > * sun8i_ce_get_engine_number() get the next channel slot
> > * This is a simple round-robin way of getting the next channel
> > + * The flow 3 is reserve for xRNG operations
> > */
> > int sun8i_ce_get_engine_number(struct sun8i_ce_dev *ce)
> > {
> > - return atomic_inc_return(&ce->flow) % MAXFLOW;
> > + return atomic_inc_return(&ce->flow) % (MAXFLOW - 1);
> > }
> >
> > int sun8i_ce_run_task(struct sun8i_ce_dev *ce, int flow, const char *name)
> > @@ -130,6 +138,7 @@ int sun8i_ce_run_task(struct sun8i_ce_dev *ce, int flow,
> > const char *name) #endif
> >
> > mutex_lock(&ce->mlock);
> > + mutex_init(&ce->rnglock);
> >
> > v = readl(ce->base + CE_ICR);
> > v |= 1 << flow;
> > @@ -516,6 +525,25 @@ static struct sun8i_ce_alg_template ce_algs[] = {
> > }
> > },
> > #endif
> > +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_PRNG
> > +{
> > + .type = CRYPTO_ALG_TYPE_RNG,
> > + .alg.rng = {
> > + .base = {
> > + .cra_name = "stdrng",
> > + .cra_driver_name = "sun8i-ce-prng",
> > + .cra_priority = 300,
> > + .cra_ctxsize = sizeof(struct
> sun8i_ce_rng_tfm_ctx),
> > + .cra_module = THIS_MODULE,
> > + .cra_init = sun8i_ce_prng_init,
> > + .cra_exit = sun8i_ce_prng_exit,
> > + },
> > + .generate = sun8i_ce_prng_generate,
> > + .seed = sun8i_ce_prng_seed,
> > + .seedsize = PRNG_SEED_SIZE,
> > + }
> > +},
> > +#endif
> > };
> >
> > #ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
> > @@ -543,6 +571,12 @@ static int sun8i_ce_dbgfs_read(struct seq_file *seq,
> > void *v) ce_algs[i].alg.hash.halg.base.cra_name,
> > ce_algs[i].stat_req, ce_algs[i].stat_fb);
> > break;
> > + case CRYPTO_ALG_TYPE_RNG:
> > + seq_printf(seq, "%s %s %lu %lu\n",
> > + ce_algs[i].alg.rng.base.cra_driver_name,
> > + ce_algs[i].alg.rng.base.cra_name,
> > + ce_algs[i].stat_req,
> ce_algs[i].stat_bytes);
> > + break;
> > }
> > }
> > return 0;
> > @@ -777,6 +811,23 @@ static int sun8i_ce_register_algs(struct sun8i_ce_dev
> > *ce) return err;
> > }
> > break;
> > + case CRYPTO_ALG_TYPE_RNG:
> > + if (ce->variant->prng == CE_ID_NOTSUPP) {
> > + dev_info(ce->dev,
> > + "DEBUG: Algo of %s not supported\n",
> > + ce_algs[i].alg.rng.base.cra_name);
> > + ce_algs[i].ce = NULL;
> > + break;
> > + }
> > + dev_info(ce->dev, "Register %s\n",
> > + ce_algs[i].alg.rng.base.cra_name);
> > + err = crypto_register_rng(&ce_algs[i].alg.rng);
> > + if (err) {
> > + dev_err(ce->dev, "Fail to register %s\n",
> > + ce_algs[i].alg.rng.base.cra_name);
> > + ce_algs[i].ce = NULL;
> > + }
> > + break;
> > default:
> > ce_algs[i].ce = NULL;
> > dev_err(ce->dev, "ERROR: tried to register an unknown
> algo\n");
> > @@ -803,6 +854,11 @@ static void sun8i_ce_unregister_algs(struct
> > sun8i_ce_dev *ce) ce_algs[i].alg.hash.halg.base.cra_name);
> > crypto_unregister_ahash(&ce_algs[i].alg.hash);
> > break;
> > + case CRYPTO_ALG_TYPE_RNG:
> > + dev_info(ce->dev, "Unregister %d %s\n", i,
> > + ce_algs[i].alg.rng.base.cra_name);
> > + crypto_unregister_rng(&ce_algs[i].alg.rng);
> > + break;
> > }
> > }
> > }
> > diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-prng.c
> > b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-prng.c new file mode 100644
> > index 000000000000..8f82bfc2c54c
> > --- /dev/null
> > +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-prng.c
> > @@ -0,0 +1,189 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * sun8i-ce-prng.c - hardware cryptographic offloader for
> > + * Allwinner H3/A64/H5/H2+/H6/R40 SoC
> > + *
> > + * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
> > + *
> > + * This file handle the PRNG
> > + *
> > + * You could find a link for the datasheet in
> > Documentation/arm/sunxi/README + */
> > +#include "sun8i-ce.h"
> > +#include <linux/pm_runtime.h>
> > +#include <crypto/internal/rng.h>
> > +
> > +int sun8i_ce_prng_init(struct crypto_tfm *tfm)
> > +{
> > + struct sun8i_ce_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
> > +
> > + memset(ctx, 0, sizeof(struct sun8i_ce_rng_tfm_ctx));
> > + return 0;
> > +}
> > +
> > +void sun8i_ce_prng_exit(struct crypto_tfm *tfm)
> > +{
> > + struct sun8i_ce_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
> > +
> > + kfree(ctx->seed);
> > + ctx->seed = NULL;
> > + ctx->slen = 0;
> > +}
> > +
> > +int sun8i_ce_prng_seed(struct crypto_rng *tfm, const u8 *seed,
> > + unsigned int slen)
> > +{
> > + struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
> > +
> > + if (ctx->seed && ctx->slen != slen) {
> > + ctx->slen = 0;
> > + kfree(ctx->seed);
>
> kzfree?
>

Yes

> > + ctx->seed = NULL;
> > + }
> > + if (!ctx->seed)
> > + ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA);
> > + if (!ctx->seed)
> > + return -ENOMEM;
> > +
> > + memcpy(ctx->seed, seed, slen);
> > + ctx->slen = slen;
> > +
> > + return 0;
> > +}
> > +
> > +int sun8i_ce_prng_generate(struct crypto_rng *tfm, const u8 *src,
> > + unsigned int slen, u8 *dst, unsigned int dlen)
> > +{
> > + struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
> > + struct rng_alg *alg = crypto_rng_alg(tfm);
> > + struct sun8i_ce_alg_template *algt;
> > + struct sun8i_ce_dev *ce;
> > + dma_addr_t dma_iv, dma_dst;
> > + int err = 0;
> > + int flow = 3;
> > + unsigned int todo;
> > + struct sun8i_ce_flow *chan;
> > + struct ce_task *cet;
> > + u32 common, sym;
> > + dma_addr_t dma_next, dma_key;
> > + void *next, *key;
> > + void *d;
> > +
> > + algt = container_of(alg, struct sun8i_ce_alg_template, alg.rng);
> > + ce = algt->ce;
> > +
> > + if (ctx->slen == 0) {
> > + dev_err(ce->dev, "not seeded\n");
> > + return -EINVAL;
> > + }
> > +
> > + next = kzalloc(256, GFP_KERNEL | GFP_DMA);
> > + if (!next)
> > + return -ENOMEM;
> > +
> > + key = kzalloc(256, GFP_KERNEL | GFP_DMA);
> > + if (!key)
> > + return -ENOMEM;
>
> You leak memory here.
>

Thanks will fix.
Furthermore, I just saw that key is unused, I forgot to clean it.
And thoses hardcoded 256 are bad.

> > +
> > + /* we want dlen + seedsize rounded up to a multiple of PRNG_DATA_SIZE
> */
> > + todo = dlen + ctx->slen + PRNG_DATA_SIZE * 2;
> > + todo -= todo % PRNG_DATA_SIZE;
> > +
> > + d = kzalloc(todo + 20, GFP_KERNEL | GFP_DMA);
> > + if (!d)
> > + return -ENOMEM;
> > +
> > + dev_dbg(ce->dev, "%s PRNG slen=%u dlen=%u todo=%u multi=%u\n",
> __func__,
> > + slen, dlen, todo, todo / PRNG_DATA_SIZE);
> > +
> > + if (ctx->slen == 0) {
> > + dev_err(ce->dev, "not seeded\n");
> > + return -EINVAL;
> > + }
> > +
> > +#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
> > + algt->stat_req++;
> > + algt->stat_bytes += todo;
> > +#endif
> > +
> > + dma_iv = dma_map_single(ce->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE);
> > + if (dma_mapping_error(ce->dev, dma_iv)) {
> > + dev_err(ce->dev, "Cannot DMA MAP IV\n");
> > + return -EFAULT;
> > + }
> > +
> > + dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
> > + if (dma_mapping_error(ce->dev, dma_dst)) {
> > + dev_err(ce->dev, "Cannot DMA MAP DST\n");
> > + err = -EFAULT;
> > + goto err_iv;
> > + }
> > +
> > + dma_next = dma_map_single(ce->dev, next, 256, DMA_FROM_DEVICE);
> > + if (dma_mapping_error(ce->dev, dma_next)) {
> > + dev_err(ce->dev, "Cannot DMA MAP NEXT\n");
> > + err = -EFAULT;
> > + goto err_iv;
> > + }
> > +
> > + dma_key = dma_map_single(ce->dev, key, 256, DMA_FROM_DEVICE);
> > + if (dma_mapping_error(ce->dev, dma_key)) {
> > + dev_err(ce->dev, "Cannot DMA MAP NEXT\n");
> > + err = -EFAULT;
> > + goto err_iv;
> > + }
> > +
> > + err = pm_runtime_get_sync(ce->dev);
> > + if (err < 0)
> > + goto err_pm;
> > +
> > + mutex_lock(&ce->rnglock);
> > + chan = &ce->chanlist[flow];
> > +
> > + cet = &chan->tl[0];
> > + memset(cet, 0, sizeof(struct ce_task));
> > +
> > + cet->t_id = cpu_to_le32(flow);
> > + common = ce->variant->prng | CE_COMM_INT;
> > + cet->t_common_ctl = cpu_to_le32(common);
> > +
> > + /* recent CE (H6) need length in bytes, in word otherwise */
> > + if (ce->variant->prng_t_dlen_in_bytes)
> > + cet->t_dlen = cpu_to_le32(todo);
> > + else
> > + cet->t_dlen = cpu_to_le32(todo / 4);
> > +
> > + sym = PRNG_LD;
> > + cet->t_sym_ctl = cpu_to_le32(sym);
> > + cet->t_asym_ctl = 0;
> > +
> > + cet->t_key = cpu_to_le32(dma_key);
> > + cet->t_key = cpu_to_le32(dma_iv);
> > + cet->t_iv = cpu_to_le32(dma_iv);
> > + cet->t_ctr = cpu_to_le32(dma_next);
> > +
> > + cet->t_dst[0].addr = cpu_to_le32(dma_dst);
> > + cet->t_dst[0].len = cpu_to_le32(todo / 4);
> > + ce->chanlist[flow].timeout = 2000;
> > +
> > + err = sun8i_ce_run_task(ce, 3, "PRNG");
> > + mutex_unlock(&ce->rnglock);
> > +
> > + pm_runtime_put(ce->dev);
> > +
> > + dma_unmap_single(ce->dev, dma_key, 256, DMA_FROM_DEVICE);
> > + dma_unmap_single(ce->dev, dma_next, 256, DMA_FROM_DEVICE);
> > +err_pm:
> > + dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
> > +err_iv:
> > + dma_unmap_single(ce->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
> > +
> > + if (!err) {
> > + memcpy(dst, d, dlen);
> > + memcpy(ctx->seed, d + dlen, ctx->slen);
> > + }
> > + kfree(next);
> > + kfree(key);
> > + kfree(d);
>
> Shouldn't they all be kzfree?
>

Yes
Probably it miss also a memzero_explicit, I think that seeds/data are sensitive

Thanks