[PATCH 4.1 41/84] crypto: nx - Fix reentrancy bugs

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@gondor.apana.org.au>

commit 030f4e968741d65aea9cd5f7814d1164967801ef upstream.

This patch fixes a host of reentrancy bugs in the nx driver.  The
following algorithms are affected:

* CCM
* GCM
* CTR
* XCBC
* SHA256
* SHA512

The crypto API allows a single transform to be used by multiple
threads simultaneously.  For example, IPsec will use a single tfm
to process packets for a given SA.  As packets may arrive on
multiple CPUs that tfm must be reentrant.

The nx driver does try to deal with this by using a spin lock.
Unfortunately only the basic AES/CBC/ECB algorithms do this in
the correct way.

The symptom of these bugs may range from the generation of incorrect
output to memory corruption.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/crypto/nx/nx-aes-ccm.c  |    6 ++-
 drivers/crypto/nx/nx-aes-ctr.c  |    7 ++--
 drivers/crypto/nx/nx-aes-gcm.c  |   17 +++++----
 drivers/crypto/nx/nx-aes-xcbc.c |   70 +++++++++++++++++++++++++---------------
 drivers/crypto/nx/nx-sha256.c   |   43 +++++++++++++-----------
 drivers/crypto/nx/nx-sha512.c   |   44 ++++++++++++++-----------
 drivers/crypto/nx/nx.c          |    2 +
 drivers/crypto/nx/nx.h          |   14 ++++++--
 8 files changed, 124 insertions(+), 79 deletions(-)

--- a/drivers/crypto/nx/nx-aes-ccm.c
+++ b/drivers/crypto/nx/nx-aes-ccm.c
@@ -494,8 +494,9 @@ out:
 static int ccm4309_aes_nx_encrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
 	struct blkcipher_desc desc;
-	u8 *iv = nx_ctx->priv.ccm.iv;
+	u8 *iv = rctx->iv;
 
 	iv[0] = 3;
 	memcpy(iv + 1, nx_ctx->priv.ccm.nonce, 3);
@@ -525,8 +526,9 @@ static int ccm_aes_nx_encrypt(struct aea
 static int ccm4309_aes_nx_decrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
 	struct blkcipher_desc desc;
-	u8 *iv = nx_ctx->priv.ccm.iv;
+	u8 *iv = rctx->iv;
 
 	iv[0] = 3;
 	memcpy(iv + 1, nx_ctx->priv.ccm.nonce, 3);
--- a/drivers/crypto/nx/nx-aes-ctr.c
+++ b/drivers/crypto/nx/nx-aes-ctr.c
@@ -72,7 +72,7 @@ static int ctr3686_aes_nx_set_key(struct
 	if (key_len < CTR_RFC3686_NONCE_SIZE)
 		return -EINVAL;
 
-	memcpy(nx_ctx->priv.ctr.iv,
+	memcpy(nx_ctx->priv.ctr.nonce,
 	       in_key + key_len - CTR_RFC3686_NONCE_SIZE,
 	       CTR_RFC3686_NONCE_SIZE);
 
@@ -131,14 +131,15 @@ static int ctr3686_aes_nx_crypt(struct b
 				unsigned int           nbytes)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_blkcipher_ctx(desc->tfm);
-	u8 *iv = nx_ctx->priv.ctr.iv;
+	u8 iv[16];
 
+	memcpy(iv, nx_ctx->priv.ctr.nonce, CTR_RFC3686_IV_SIZE);
 	memcpy(iv + CTR_RFC3686_NONCE_SIZE,
 	       desc->info, CTR_RFC3686_IV_SIZE);
 	iv[12] = iv[13] = iv[14] = 0;
 	iv[15] = 1;
 
-	desc->info = nx_ctx->priv.ctr.iv;
+	desc->info = iv;
 
 	return ctr_aes_nx_crypt(desc, dst, src, nbytes);
 }
--- a/drivers/crypto/nx/nx-aes-gcm.c
+++ b/drivers/crypto/nx/nx-aes-gcm.c
@@ -330,6 +330,7 @@ out:
 static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
 	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
 	struct blkcipher_desc desc;
 	unsigned int nbytes = req->cryptlen;
@@ -339,7 +340,7 @@ static int gcm_aes_nx_crypt(struct aead_
 
 	spin_lock_irqsave(&nx_ctx->lock, irq_flags);
 
-	desc.info = nx_ctx->priv.gcm.iv;
+	desc.info = rctx->iv;
 	/* initialize the counter */
 	*(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;
 
@@ -434,8 +435,8 @@ out:
 
 static int gcm_aes_nx_encrypt(struct aead_request *req)
 {
-	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
-	char *iv = nx_ctx->priv.gcm.iv;
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
+	char *iv = rctx->iv;
 
 	memcpy(iv, req->iv, 12);
 
@@ -444,8 +445,8 @@ static int gcm_aes_nx_encrypt(struct aea
 
 static int gcm_aes_nx_decrypt(struct aead_request *req)
 {
-	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
-	char *iv = nx_ctx->priv.gcm.iv;
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
+	char *iv = rctx->iv;
 
 	memcpy(iv, req->iv, 12);
 
@@ -455,7 +456,8 @@ static int gcm_aes_nx_decrypt(struct aea
 static int gcm4106_aes_nx_encrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
-	char *iv = nx_ctx->priv.gcm.iv;
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
+	char *iv = rctx->iv;
 	char *nonce = nx_ctx->priv.gcm.nonce;
 
 	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
@@ -467,7 +469,8 @@ static int gcm4106_aes_nx_encrypt(struct
 static int gcm4106_aes_nx_decrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
-	char *iv = nx_ctx->priv.gcm.iv;
+	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
+	char *iv = rctx->iv;
 	char *nonce = nx_ctx->priv.gcm.nonce;
 
 	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
--- a/drivers/crypto/nx/nx-aes-xcbc.c
+++ b/drivers/crypto/nx/nx-aes-xcbc.c
@@ -42,6 +42,7 @@ static int nx_xcbc_set_key(struct crypto
 			   unsigned int         key_len)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_shash_ctx(desc);
+	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
 
 	switch (key_len) {
 	case AES_KEYSIZE_128:
@@ -51,7 +52,7 @@ static int nx_xcbc_set_key(struct crypto
 		return -EINVAL;
 	}
 
-	memcpy(nx_ctx->priv.xcbc.key, in_key, key_len);
+	memcpy(csbcpb->cpb.aes_xcbc.key, in_key, key_len);
 
 	return 0;
 }
@@ -148,32 +149,29 @@ out:
 	return rc;
 }
 
-static int nx_xcbc_init(struct shash_desc *desc)
+static int nx_crypto_ctx_aes_xcbc_init2(struct crypto_tfm *tfm)
 {
-	struct xcbc_state *sctx = shash_desc_ctx(desc);
-	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(tfm);
 	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
-	struct nx_sg *out_sg;
-	int len;
+	int err;
 
-	nx_ctx_init(nx_ctx, HCOP_FC_AES);
+	err = nx_crypto_ctx_aes_xcbc_init(tfm);
+	if (err)
+		return err;
 
-	memset(sctx, 0, sizeof *sctx);
+	nx_ctx_init(nx_ctx, HCOP_FC_AES);
 
 	NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
 	csbcpb->cpb.hdr.mode = NX_MODE_AES_XCBC_MAC;
 
-	memcpy(csbcpb->cpb.aes_xcbc.key, nx_ctx->priv.xcbc.key, AES_BLOCK_SIZE);
-	memset(nx_ctx->priv.xcbc.key, 0, sizeof *nx_ctx->priv.xcbc.key);
-
-	len = AES_BLOCK_SIZE;
-	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
-				  &len, nx_ctx->ap->sglen);
+	return 0;
+}
 
-	if (len != AES_BLOCK_SIZE)
-		return -EINVAL;
+static int nx_xcbc_init(struct shash_desc *desc)
+{
+	struct xcbc_state *sctx = shash_desc_ctx(desc);
 
-	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
+	memset(sctx, 0, sizeof *sctx);
 
 	return 0;
 }
@@ -186,6 +184,7 @@ static int nx_xcbc_update(struct shash_d
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
 	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
 	struct nx_sg *in_sg;
+	struct nx_sg *out_sg;
 	u32 to_process = 0, leftover, total;
 	unsigned int max_sg_len;
 	unsigned long irq_flags;
@@ -213,6 +212,17 @@ static int nx_xcbc_update(struct shash_d
 	max_sg_len = min_t(u64, max_sg_len,
 				nx_ctx->ap->databytelen/NX_PAGE_SIZE);
 
+	data_len = AES_BLOCK_SIZE;
+	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
+				  &len, nx_ctx->ap->sglen);
+
+	if (data_len != AES_BLOCK_SIZE) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
+
 	do {
 		to_process = total - to_process;
 		to_process = to_process & ~(AES_BLOCK_SIZE - 1);
@@ -235,8 +245,10 @@ static int nx_xcbc_update(struct shash_d
 						(u8 *) sctx->buffer,
 						&data_len,
 						max_sg_len);
-			if (data_len != sctx->count)
-				return -EINVAL;
+			if (data_len != sctx->count) {
+				rc = -EINVAL;
+				goto out;
+			}
 		}
 
 		data_len = to_process - sctx->count;
@@ -245,8 +257,10 @@ static int nx_xcbc_update(struct shash_d
 					&data_len,
 					max_sg_len);
 
-		if (data_len != to_process - sctx->count)
-			return -EINVAL;
+		if (data_len != to_process - sctx->count) {
+			rc = -EINVAL;
+			goto out;
+		}
 
 		nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) *
 					sizeof(struct nx_sg);
@@ -325,15 +339,19 @@ static int nx_xcbc_final(struct shash_de
 	in_sg = nx_build_sg_list(nx_ctx->in_sg, (u8 *)sctx->buffer,
 				 &len, nx_ctx->ap->sglen);
 
-	if (len != sctx->count)
-		return -EINVAL;
+	if (len != sctx->count) {
+		rc = -EINVAL;
+		goto out;
+	}
 
 	len = AES_BLOCK_SIZE;
 	out_sg = nx_build_sg_list(nx_ctx->out_sg, out, &len,
 				  nx_ctx->ap->sglen);
 
-	if (len != AES_BLOCK_SIZE)
-		return -EINVAL;
+	if (len != AES_BLOCK_SIZE) {
+		rc = -EINVAL;
+		goto out;
+	}
 
 	nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) * sizeof(struct nx_sg);
 	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
@@ -372,7 +390,7 @@ struct shash_alg nx_shash_aes_xcbc_alg =
 		.cra_blocksize   = AES_BLOCK_SIZE,
 		.cra_module      = THIS_MODULE,
 		.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
-		.cra_init        = nx_crypto_ctx_aes_xcbc_init,
+		.cra_init        = nx_crypto_ctx_aes_xcbc_init2,
 		.cra_exit        = nx_crypto_ctx_exit,
 	}
 };
--- a/drivers/crypto/nx/nx-sha256.c
+++ b/drivers/crypto/nx/nx-sha256.c
@@ -29,34 +29,28 @@
 #include "nx.h"
 
 
-static int nx_sha256_init(struct shash_desc *desc)
+static int nx_crypto_ctx_sha256_init(struct crypto_tfm *tfm)
 {
-	struct sha256_state *sctx = shash_desc_ctx(desc);
-	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
-	struct nx_sg *out_sg;
-	int len;
-	u32 max_sg_len;
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(tfm);
+	int err;
 
-	nx_ctx_init(nx_ctx, HCOP_FC_SHA);
+	err = nx_crypto_ctx_sha_init(tfm);
+	if (err)
+		return err;
 
-	memset(sctx, 0, sizeof *sctx);
+	nx_ctx_init(nx_ctx, HCOP_FC_SHA);
 
 	nx_ctx->ap = &nx_ctx->props[NX_PROPS_SHA256];
 
 	NX_CPB_SET_DIGEST_SIZE(nx_ctx->csbcpb, NX_DS_SHA256);
 
-	max_sg_len = min_t(u64, nx_ctx->ap->sglen,
-			nx_driver.of.max_sg_len/sizeof(struct nx_sg));
-	max_sg_len = min_t(u64, max_sg_len,
-			nx_ctx->ap->databytelen/NX_PAGE_SIZE);
+	return 0;
+}
 
-	len = SHA256_DIGEST_SIZE;
-	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
-				  &len, max_sg_len);
-	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
+static int nx_sha256_init(struct shash_desc *desc) {
+	struct sha256_state *sctx = shash_desc_ctx(desc);
 
-	if (len != SHA256_DIGEST_SIZE)
-		return -EINVAL;
+	memset(sctx, 0, sizeof *sctx);
 
 	sctx->state[0] = __cpu_to_be32(SHA256_H0);
 	sctx->state[1] = __cpu_to_be32(SHA256_H1);
@@ -78,6 +72,7 @@ static int nx_sha256_update(struct shash
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
 	struct nx_csbcpb *csbcpb = (struct nx_csbcpb *)nx_ctx->csbcpb;
 	struct nx_sg *in_sg;
+	struct nx_sg *out_sg;
 	u64 to_process = 0, leftover, total;
 	unsigned long irq_flags;
 	int rc = 0;
@@ -108,6 +103,16 @@ static int nx_sha256_update(struct shash
 	max_sg_len = min_t(u64, max_sg_len,
 			nx_ctx->ap->databytelen/NX_PAGE_SIZE);
 
+	data_len = SHA256_DIGEST_SIZE;
+	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
+				  &data_len, max_sg_len);
+	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
+
+	if (data_len != SHA256_DIGEST_SIZE) {
+		rc = -EINVAL;
+		goto out;
+	}
+
 	do {
 		/*
 		 * to_process: the SHA256_BLOCK_SIZE data chunk to process in
@@ -282,7 +287,7 @@ struct shash_alg nx_shash_sha256_alg = {
 		.cra_blocksize   = SHA256_BLOCK_SIZE,
 		.cra_module      = THIS_MODULE,
 		.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
-		.cra_init        = nx_crypto_ctx_sha_init,
+		.cra_init        = nx_crypto_ctx_sha256_init,
 		.cra_exit        = nx_crypto_ctx_exit,
 	}
 };
--- a/drivers/crypto/nx/nx-sha512.c
+++ b/drivers/crypto/nx/nx-sha512.c
@@ -28,34 +28,29 @@
 #include "nx.h"
 
 
-static int nx_sha512_init(struct shash_desc *desc)
+static int nx_crypto_ctx_sha512_init(struct crypto_tfm *tfm)
 {
-	struct sha512_state *sctx = shash_desc_ctx(desc);
-	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
-	struct nx_sg *out_sg;
-	int len;
-	u32 max_sg_len;
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(tfm);
+	int err;
 
-	nx_ctx_init(nx_ctx, HCOP_FC_SHA);
+	err = nx_crypto_ctx_sha_init(tfm);
+	if (err)
+		return err;
 
-	memset(sctx, 0, sizeof *sctx);
+	nx_ctx_init(nx_ctx, HCOP_FC_SHA);
 
 	nx_ctx->ap = &nx_ctx->props[NX_PROPS_SHA512];
 
 	NX_CPB_SET_DIGEST_SIZE(nx_ctx->csbcpb, NX_DS_SHA512);
 
-	max_sg_len = min_t(u64, nx_ctx->ap->sglen,
-			nx_driver.of.max_sg_len/sizeof(struct nx_sg));
-	max_sg_len = min_t(u64, max_sg_len,
-			nx_ctx->ap->databytelen/NX_PAGE_SIZE);
+	return 0;
+}
 
-	len = SHA512_DIGEST_SIZE;
-	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
-				  &len, max_sg_len);
-	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
+static int nx_sha512_init(struct shash_desc *desc)
+{
+	struct sha512_state *sctx = shash_desc_ctx(desc);
 
-	if (len != SHA512_DIGEST_SIZE)
-		return -EINVAL;
+	memset(sctx, 0, sizeof *sctx);
 
 	sctx->state[0] = __cpu_to_be64(SHA512_H0);
 	sctx->state[1] = __cpu_to_be64(SHA512_H1);
@@ -77,6 +72,7 @@ static int nx_sha512_update(struct shash
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&desc->tfm->base);
 	struct nx_csbcpb *csbcpb = (struct nx_csbcpb *)nx_ctx->csbcpb;
 	struct nx_sg *in_sg;
+	struct nx_sg *out_sg;
 	u64 to_process, leftover = 0, total;
 	unsigned long irq_flags;
 	int rc = 0;
@@ -107,6 +103,16 @@ static int nx_sha512_update(struct shash
 	max_sg_len = min_t(u64, max_sg_len,
 			nx_ctx->ap->databytelen/NX_PAGE_SIZE);
 
+	data_len = SHA512_DIGEST_SIZE;
+	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *)sctx->state,
+				  &data_len, max_sg_len);
+	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
+
+	if (data_len != SHA512_DIGEST_SIZE) {
+		rc = -EINVAL;
+		goto out;
+	}
+
 	do {
 		/*
 		 * to_process: the SHA512_BLOCK_SIZE data chunk to process in
@@ -288,7 +294,7 @@ struct shash_alg nx_shash_sha512_alg = {
 		.cra_blocksize   = SHA512_BLOCK_SIZE,
 		.cra_module      = THIS_MODULE,
 		.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
-		.cra_init        = nx_crypto_ctx_sha_init,
+		.cra_init        = nx_crypto_ctx_sha512_init,
 		.cra_exit        = nx_crypto_ctx_exit,
 	}
 };
--- a/drivers/crypto/nx/nx.c
+++ b/drivers/crypto/nx/nx.c
@@ -635,12 +635,14 @@ static int nx_crypto_ctx_init(struct nx_
 /* entry points from the crypto tfm initializers */
 int nx_crypto_ctx_aes_ccm_init(struct crypto_tfm *tfm)
 {
+	tfm->crt_aead.reqsize = sizeof(struct nx_ccm_rctx);
 	return nx_crypto_ctx_init(crypto_tfm_ctx(tfm), NX_FC_AES,
 				  NX_MODE_AES_CCM);
 }
 
 int nx_crypto_ctx_aes_gcm_init(struct crypto_tfm *tfm)
 {
+	tfm->crt_aead.reqsize = sizeof(struct nx_gcm_rctx);
 	return nx_crypto_ctx_init(crypto_tfm_ctx(tfm), NX_FC_AES,
 				  NX_MODE_AES_GCM);
 }
--- a/drivers/crypto/nx/nx.h
+++ b/drivers/crypto/nx/nx.h
@@ -2,6 +2,8 @@
 #ifndef __NX_H__
 #define __NX_H__
 
+#include <crypto/ctr.h>
+
 #define NX_NAME		"nx-crypto"
 #define NX_STRING	"IBM Power7+ Nest Accelerator Crypto Driver"
 #define NX_VERSION	"1.0"
@@ -91,8 +93,11 @@ struct nx_crypto_driver {
 
 #define NX_GCM4106_NONCE_LEN		(4)
 #define NX_GCM_CTR_OFFSET		(12)
-struct nx_gcm_priv {
+struct nx_gcm_rctx {
 	u8 iv[16];
+};
+
+struct nx_gcm_priv {
 	u8 iauth_tag[16];
 	u8 nonce[NX_GCM4106_NONCE_LEN];
 };
@@ -100,8 +105,11 @@ struct nx_gcm_priv {
 #define NX_CCM_AES_KEY_LEN		(16)
 #define NX_CCM4309_AES_KEY_LEN		(19)
 #define NX_CCM4309_NONCE_LEN		(3)
-struct nx_ccm_priv {
+struct nx_ccm_rctx {
 	u8 iv[16];
+};
+
+struct nx_ccm_priv {
 	u8 b0[16];
 	u8 iauth_tag[16];
 	u8 oauth_tag[16];
@@ -113,7 +121,7 @@ struct nx_xcbc_priv {
 };
 
 struct nx_ctr_priv {
-	u8 iv[16];
+	u8 nonce[CTR_RFC3686_NONCE_SIZE];
 };
 
 struct nx_crypto_ctx {