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Subject[PATCH v3 01/10] crypto: caam/jr - add fallback for XTS with more than 8B IV
Date
From: Andrei Botila <andrei.botila@nxp.com>

A hardware limitation exists for CAAM until Era 9 which restricts
the accelerator to IVs with only 8 bytes. When CAAM has a lower era
a fallback is necessary to process 16 bytes IV.

Fixes: c6415a6016bf ("crypto: caam - add support for acipher xts(aes)")
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Andrei Botila <andrei.botila@nxp.com>
---
drivers/crypto/caam/Kconfig | 1 +
drivers/crypto/caam/caamalg.c | 72 +++++++++++++++++++++++++++++++----
2 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/caam/Kconfig b/drivers/crypto/caam/Kconfig
index bc35aa0ec07a..dfeaad8dfe81 100644
--- a/drivers/crypto/caam/Kconfig
+++ b/drivers/crypto/caam/Kconfig
@@ -101,6 +101,7 @@ config CRYPTO_DEV_FSL_CAAM_CRYPTO_API
select CRYPTO_AUTHENC
select CRYPTO_SKCIPHER
select CRYPTO_LIB_DES
+ select CRYPTO_XTS
help
Selecting this will offload crypto for users of the
scatterlist crypto API (such as the linux native IPSec
diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index 91feda5b63f6..adb2c05a8bde 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -57,6 +57,7 @@
#include "key_gen.h"
#include "caamalg_desc.h"
#include <crypto/engine.h>
+#include <asm/unaligned.h>

/*
* crypto alg
@@ -114,10 +115,12 @@ struct caam_ctx {
struct alginfo adata;
struct alginfo cdata;
unsigned int authsize;
+ struct crypto_skcipher *fallback;
};

struct caam_skcipher_req_ctx {
struct skcipher_edesc *edesc;
+ struct skcipher_request fallback_req;
};

struct caam_aead_req_ctx {
@@ -830,12 +833,17 @@ static int xts_skcipher_setkey(struct crypto_skcipher *skcipher, const u8 *key,
struct caam_ctx *ctx = crypto_skcipher_ctx(skcipher);
struct device *jrdev = ctx->jrdev;
u32 *desc;
+ int err;

if (keylen != 2 * AES_MIN_KEY_SIZE && keylen != 2 * AES_MAX_KEY_SIZE) {
dev_dbg(jrdev, "key size mismatch\n");
return -EINVAL;
}

+ err = crypto_skcipher_setkey(ctx->fallback, key, keylen);
+ if (err)
+ return err;
+
ctx->cdata.keylen = keylen;
ctx->cdata.key_virt = key;
ctx->cdata.key_inline = true;
@@ -1755,6 +1763,14 @@ static int skcipher_do_one_req(struct crypto_engine *engine, void *areq)
return ret;
}

+static inline bool xts_skcipher_ivsize(struct skcipher_request *req)
+{
+ struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
+ unsigned int ivsize = crypto_skcipher_ivsize(skcipher);
+
+ return !!get_unaligned((u64 *)(req->iv + (ivsize / 2)));
+}
+
static inline int skcipher_crypt(struct skcipher_request *req, bool encrypt)
{
struct skcipher_edesc *edesc;
@@ -1768,6 +1784,21 @@ static inline int skcipher_crypt(struct skcipher_request *req, bool encrypt)
if (!req->cryptlen)
return 0;

+ if (ctx->fallback && xts_skcipher_ivsize(req)) {
+ struct caam_skcipher_req_ctx *rctx = skcipher_request_ctx(req);
+
+ skcipher_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+ skcipher_request_set_callback(&rctx->fallback_req,
+ req->base.flags,
+ req->base.complete,
+ req->base.data);
+ skcipher_request_set_crypt(&rctx->fallback_req, req->src,
+ req->dst, req->cryptlen, req->iv);
+
+ return encrypt ? crypto_skcipher_encrypt(&rctx->fallback_req) :
+ crypto_skcipher_decrypt(&rctx->fallback_req);
+ }
+
/* allocate extended descriptor */
edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
if (IS_ERR(edesc))
@@ -1905,6 +1936,7 @@ static struct caam_skcipher_alg driver_algs[] = {
.base = {
.cra_name = "xts(aes)",
.cra_driver_name = "xts-aes-caam",
+ .cra_flags = CRYPTO_ALG_NEED_FALLBACK,
.cra_blocksize = AES_BLOCK_SIZE,
},
.setkey = xts_skcipher_setkey,
@@ -3344,13 +3376,35 @@ static int caam_cra_init(struct crypto_skcipher *tfm)
struct caam_skcipher_alg *caam_alg =
container_of(alg, typeof(*caam_alg), skcipher);
struct caam_ctx *ctx = crypto_skcipher_ctx(tfm);
-
- crypto_skcipher_set_reqsize(tfm, sizeof(struct caam_skcipher_req_ctx));
+ u32 alg_aai = caam_alg->caam.class1_alg_type & OP_ALG_AAI_MASK;
+ int ret = 0;

ctx->enginectx.op.do_one_request = skcipher_do_one_req;

- return caam_init_common(crypto_skcipher_ctx(tfm), &caam_alg->caam,
- false);
+ if (alg_aai == OP_ALG_AAI_XTS) {
+ const char *tfm_name = crypto_tfm_alg_name(&tfm->base);
+ struct crypto_skcipher *fallback;
+
+ fallback = crypto_alloc_skcipher(tfm_name, 0,
+ CRYPTO_ALG_NEED_FALLBACK);
+ if (IS_ERR(fallback)) {
+ dev_err(ctx->jrdev, "Failed to allocate %s fallback: %ld\n",
+ tfm_name, PTR_ERR(fallback));
+ return PTR_ERR(fallback);
+ }
+
+ ctx->fallback = fallback;
+ crypto_skcipher_set_reqsize(tfm, sizeof(struct caam_skcipher_req_ctx) +
+ crypto_skcipher_reqsize(fallback));
+ } else {
+ crypto_skcipher_set_reqsize(tfm, sizeof(struct caam_skcipher_req_ctx));
+ }
+
+ ret = caam_init_common(ctx, &caam_alg->caam, false);
+ if (ret && ctx->fallback)
+ crypto_free_skcipher(ctx->fallback);
+
+ return ret;
}

static int caam_aead_init(struct crypto_aead *tfm)
@@ -3378,7 +3432,11 @@ static void caam_exit_common(struct caam_ctx *ctx)

static void caam_cra_exit(struct crypto_skcipher *tfm)
{
- caam_exit_common(crypto_skcipher_ctx(tfm));
+ struct caam_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ if (ctx->fallback)
+ crypto_free_skcipher(ctx->fallback);
+ caam_exit_common(ctx);
}

static void caam_aead_exit(struct crypto_aead *tfm)
@@ -3412,8 +3470,8 @@ static void caam_skcipher_alg_init(struct caam_skcipher_alg *t_alg)
alg->base.cra_module = THIS_MODULE;
alg->base.cra_priority = CAAM_CRA_PRIORITY;
alg->base.cra_ctxsize = sizeof(struct caam_ctx);
- alg->base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY |
- CRYPTO_ALG_KERN_DRIVER_ONLY;
+ alg->base.cra_flags |= (CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY |
+ CRYPTO_ALG_KERN_DRIVER_ONLY);

alg->init = caam_cra_init;
alg->exit = caam_cra_exit;
--
2.17.1
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