s390/pkey: add support for ecc clear key

Add support for a new 'non CCA clear key token' with these
ECC clear keys supported:

- ECC P256
- ECC P384
- ECC P521
- ECC ED25519
- ECC ED448

This makes it possible to derive a protected key from this
ECC clear key input via PKEY_KBLOB2PROTK3 ioctl. As of now
the only way to derive protected keys from these clear key
tokens is via PCKMO instruction. For AES keys an alternate
path via creating a secure key from the clear key and then
derive a protected key from the secure key exists. This
alternate path is not implemented for ECC keys as it would
require to rearrange and maybe recalculate the clear key
material for input to derive an CCA or EP11 ECC secure key.

Signed-off-by: Harald Freudenberger <[e-mail]>
Reviewed-by: Holger Dengler <[e-mail]>
Signed-off-by: Alexander Gordeev <[e-mail]>

arch/s390/include/asm/cpacf.h

···
 /*
  * CP Assist for Cryptographic Functions (CPACF)
  *
- * Copyright IBM Corp. 2003, 2017
+ * Copyright IBM Corp. 2003, 2023
  * Author(s): Thomas Spatzier
  *	      Jan Glauber
  *	      Harald Freudenberger ([e-mail])
···
 #define CPACF_PCKMO_ENC_AES_128_KEY	0x12
 #define CPACF_PCKMO_ENC_AES_192_KEY	0x13
 #define CPACF_PCKMO_ENC_AES_256_KEY	0x14
+#define CPACF_PCKMO_ENC_ECC_P256_KEY	0x20
+#define CPACF_PCKMO_ENC_ECC_P384_KEY	0x21
+#define CPACF_PCKMO_ENC_ECC_P521_KEY	0x22
+#define CPACF_PCKMO_ENC_ECC_ED25519_KEY	0x28
+#define CPACF_PCKMO_ENC_ECC_ED448_KEY	0x29
 
 /*
  * Function codes for the PRNO (PERFORM RANDOM NUMBER OPERATION)

arch/s390/include/uapi/asm/pkey.h

···
 /*
  * Userspace interface to the pkey device driver
  *
- * Copyright IBM Corp. 2017, 2019
+ * Copyright IBM Corp. 2017, 2023
  *
  * Author: Harald Freudenberger <[e-mail]>
  *
···
 #define MINKEYBLOBSIZE	SECKEYBLOBSIZE
 
 /* defines for the type field within the pkey_protkey struct */
-#define PKEY_KEYTYPE_AES_128		      1
-#define PKEY_KEYTYPE_AES_192		      2
-#define PKEY_KEYTYPE_AES_256		      3
-#define PKEY_KEYTYPE_ECC		      4
+#define PKEY_KEYTYPE_AES_128		1
+#define PKEY_KEYTYPE_AES_192		2
+#define PKEY_KEYTYPE_AES_256		3
+#define PKEY_KEYTYPE_ECC		4
+#define PKEY_KEYTYPE_ECC_P256		5
+#define PKEY_KEYTYPE_ECC_P384		6
+#define PKEY_KEYTYPE_ECC_P521		7
+#define PKEY_KEYTYPE_ECC_ED25519	8
+#define PKEY_KEYTYPE_ECC_ED448		9
 
 /* the newer ioctls use a pkey_key_type enum for type information */
 enum pkey_key_type {

drivers/s390/crypto/pkey_api.c

···
 /*
  *  pkey device driver
  *
- *  Copyright IBM Corp. 2017,2019
+ *  Copyright IBM Corp. 2017, 2023
+ *
  *  Author(s): Harald Freudenberger
  */
 
···
 MODULE_DESCRIPTION("s390 protected key interface");
 
 #define KEYBLOBBUFSIZE 8192	/* key buffer size used for internal processing */
+#define MINKEYBLOBBUFSIZE (sizeof(struct keytoken_header))
 #define PROTKEYBLOBBUFSIZE 256	/* protected key buffer size used internal */
 #define MAXAPQNSINLIST 64	/* max 64 apqns within a apqn list */
 #define AES_WK_VP_SIZE 32	/* Size of WK VP block appended to a prot key */
···
 } __packed;
 
 /* inside view of a clear key token (type 0x00 version 0x02) */
-struct clearaeskeytoken {
-	u8  type;	 /* 0x00 for PAES specific key tokens */
+struct clearkeytoken {
+	u8  type;	/* 0x00 for PAES specific key tokens */
 	u8  res0[3];
-	u8  version;	 /* 0x02 for clear AES key token */
+	u8  version;	/* 0x02 for clear key token */
 	u8  res1[3];
-	u32 keytype;	 /* key type, one of the PKEY_KEYTYPE values */
-	u32 len;	 /* bytes actually stored in clearkey[] */
+	u32 keytype;	/* key type, one of the PKEY_KEYTYPE_* values */
+	u32 len;	/* bytes actually stored in clearkey[] */
 	u8  clearkey[]; /* clear key value */
 } __packed;
+
+/* helper function which translates the PKEY_KEYTYPE_AES_* to their keysize */
+static inline u32 pkey_keytype_aes_to_size(u32 keytype)
+{
+	switch (keytype) {
+	case PKEY_KEYTYPE_AES_128:
+		return 16;
+	case PKEY_KEYTYPE_AES_192:
+		return 24;
+	case PKEY_KEYTYPE_AES_256:
+		return 32;
+	default:
+		return 0;
+	}
+}
 
 /*
  * Create a protected key from a clear key value via PCKMO instruction.
···
 	/* mask of available pckmo subfunctions */
 	static cpacf_mask_t pckmo_functions;
 
-	u8 paramblock[64];
+	u8 paramblock[112];
+	u32 pkeytype;
 	int keysize;
 	long fc;
 
 	switch (keytype) {
 	case PKEY_KEYTYPE_AES_128:
+		/* 16 byte key, 32 byte aes wkvp, total 48 bytes */
 		keysize = 16;
+		pkeytype = keytype;
 		fc = CPACF_PCKMO_ENC_AES_128_KEY;
 		break;
 	case PKEY_KEYTYPE_AES_192:
+		/* 24 byte key, 32 byte aes wkvp, total 56 bytes */
 		keysize = 24;
+		pkeytype = keytype;
 		fc = CPACF_PCKMO_ENC_AES_192_KEY;
 		break;
 	case PKEY_KEYTYPE_AES_256:
+		/* 32 byte key, 32 byte aes wkvp, total 64 bytes */
 		keysize = 32;
+		pkeytype = keytype;
 		fc = CPACF_PCKMO_ENC_AES_256_KEY;
+		break;
+	case PKEY_KEYTYPE_ECC_P256:
+		/* 32 byte key, 32 byte aes wkvp, total 64 bytes */
+		keysize = 32;
+		pkeytype = PKEY_KEYTYPE_ECC;
+		fc = CPACF_PCKMO_ENC_ECC_P256_KEY;
+		break;
+	case PKEY_KEYTYPE_ECC_P384:
+		/* 48 byte key, 32 byte aes wkvp, total 80 bytes */
+		keysize = 48;
+		pkeytype = PKEY_KEYTYPE_ECC;
+		fc = CPACF_PCKMO_ENC_ECC_P384_KEY;
+		break;
+	case PKEY_KEYTYPE_ECC_P521:
+		/* 80 byte key, 32 byte aes wkvp, total 112 bytes */
+		keysize = 80;
+		pkeytype = PKEY_KEYTYPE_ECC;
+		fc = CPACF_PCKMO_ENC_ECC_P521_KEY;
+		break;
+	case PKEY_KEYTYPE_ECC_ED25519:
+		/* 32 byte key, 32 byte aes wkvp, total 64 bytes */
+		keysize = 32;
+		pkeytype = PKEY_KEYTYPE_ECC;
+		fc = CPACF_PCKMO_ENC_ECC_ED25519_KEY;
+		break;
+	case PKEY_KEYTYPE_ECC_ED448:
+		/* 64 byte key, 32 byte aes wkvp, total 96 bytes */
+		keysize = 64;
+		pkeytype = PKEY_KEYTYPE_ECC;
+		fc = CPACF_PCKMO_ENC_ECC_ED448_KEY;
 		break;
 	default:
 		DEBUG_ERR("%s unknown/unsupported keytype %u\n",
···
 	/* copy created protected key to key buffer including the wkvp block */
 	*protkeylen = keysize + AES_WK_VP_SIZE;
 	memcpy(protkey, paramblock, *protkeylen);
-	*protkeytype = keytype;
+	*protkeytype = pkeytype;
 
 	return 0;
 }
···
 	int keysize;
 	int rc;
 
-	switch (keytype) {
-	case PKEY_KEYTYPE_AES_128:
-		keysize = 16;
-		break;
-	case PKEY_KEYTYPE_AES_192:
-		keysize = 24;
-		break;
-	case PKEY_KEYTYPE_AES_256:
-		keysize = 32;
-		break;
-	default:
+	keysize = pkey_keytype_aes_to_size(keytype);
+	if (!keysize) {
 		DEBUG_ERR("%s unknown/unsupported keytype %d\n", __func__,
 			  keytype);
 		return -EINVAL;
···
 	return 0;
 }
 
+/* Helper for pkey_nonccatok2pkey, handles aes clear key token */
+static int nonccatokaes2pkey(const struct clearkeytoken *t,
+			     u8 *protkey, u32 *protkeylen, u32 *protkeytype)
+{
+	size_t tmpbuflen = max_t(size_t, SECKEYBLOBSIZE, MAXEP11AESKEYBLOBSIZE);
+	u8 *tmpbuf = NULL;
+	u32 keysize;
+	int rc;
+
+	keysize = pkey_keytype_aes_to_size(t->keytype);
+	if (!keysize) {
+		DEBUG_ERR("%s unknown/unsupported keytype %u\n",
+			  __func__, t->keytype);
+		return -EINVAL;
+	}
+	if (t->len != keysize) {
+		DEBUG_ERR("%s non clear key aes token: invalid key len %u\n",
+			  __func__, t->len);
+		return -EINVAL;
+	}
+
+	/* try direct way with the PCKMO instruction */
+	rc = pkey_clr2protkey(t->keytype, t->clearkey,
+			      protkey, protkeylen, protkeytype);
+	if (!rc)
+		goto out;
+
+	/* PCKMO failed, so try the CCA secure key way */
+	tmpbuf = kmalloc(tmpbuflen, GFP_ATOMIC);
+	if (!tmpbuf)
+		return -ENOMEM;
+	zcrypt_wait_api_operational();
+	rc = cca_clr2seckey(0xFFFF, 0xFFFF, t->keytype, t->clearkey, tmpbuf);
+	if (rc)
+		goto try_via_ep11;
+	rc = pkey_skey2pkey(tmpbuf,
+			    protkey, protkeylen, protkeytype);
+	if (!rc)
+		goto out;
+
+try_via_ep11:
+	/* if the CCA way also failed, let's try via EP11 */
+	rc = pkey_clr2ep11key(t->clearkey, t->len,
+			      tmpbuf, &tmpbuflen);
+	if (rc)
+		goto failure;
+	rc = pkey_ep11key2pkey(tmpbuf,
+			       protkey, protkeylen, protkeytype);
+	if (!rc)
+		goto out;
+
+failure:
+	DEBUG_ERR("%s unable to build protected key from clear", __func__);
+
+out:
+	kfree(tmpbuf);
+	return rc;
+}
+
+/* Helper for pkey_nonccatok2pkey, handles ecc clear key token */
+static int nonccatokecc2pkey(const struct clearkeytoken *t,
+			     u8 *protkey, u32 *protkeylen, u32 *protkeytype)
+{
+	u32 keylen;
+	int rc;
+
+	switch (t->keytype) {
+	case PKEY_KEYTYPE_ECC_P256:
+		keylen = 32;
+		break;
+	case PKEY_KEYTYPE_ECC_P384:
+		keylen = 48;
+		break;
+	case PKEY_KEYTYPE_ECC_P521:
+		keylen = 80;
+		break;
+	case PKEY_KEYTYPE_ECC_ED25519:
+		keylen = 32;
+		break;
+	case PKEY_KEYTYPE_ECC_ED448:
+		keylen = 64;
+		break;
+	default:
+		DEBUG_ERR("%s unknown/unsupported keytype %u\n",
+			  __func__, t->keytype);
+		return -EINVAL;
+	}
+
+	if (t->len != keylen) {
+		DEBUG_ERR("%s non clear key ecc token: invalid key len %u\n",
+			  __func__, t->len);
+		return -EINVAL;
+	}
+
+	/* only one path possible: via PCKMO instruction */
+	rc = pkey_clr2protkey(t->keytype, t->clearkey,
+			      protkey, protkeylen, protkeytype);
+	if (rc) {
+		DEBUG_ERR("%s unable to build protected key from clear",
+			  __func__);
+	}
+
+	return rc;
+}
+
 /*
  * Transform a non-CCA key token into a protected key
  */
···
 			       u8 *protkey, u32 *protkeylen, u32 *protkeytype)
 {
 	struct keytoken_header *hdr = (struct keytoken_header *)key;
-	u8 *tmpbuf = NULL;
 	int rc = -EINVAL;
 
 	switch (hdr->version) {
···
 		break;
 	}
 	case TOKVER_CLEAR_KEY: {
-		struct clearaeskeytoken *t;
-		struct pkey_clrkey ckey;
-		union u_tmpbuf {
-			u8 skey[SECKEYBLOBSIZE];
-			u8 ep11key[MAXEP11AESKEYBLOBSIZE];
-		};
-		size_t tmpbuflen = sizeof(union u_tmpbuf);
+		struct clearkeytoken *t = (struct clearkeytoken *)key;
 
-		if (keylen < sizeof(struct clearaeskeytoken))
+		if (keylen < sizeof(struct clearkeytoken) ||
+		    keylen != sizeof(*t) + t->len)
 			goto out;
-		t = (struct clearaeskeytoken *)key;
-		if (keylen != sizeof(*t) + t->len)
-			goto out;
-		if ((t->keytype == PKEY_KEYTYPE_AES_128 && t->len == 16) ||
-		    (t->keytype == PKEY_KEYTYPE_AES_192 && t->len == 24) ||
-		    (t->keytype == PKEY_KEYTYPE_AES_256 && t->len == 32))
-			memcpy(ckey.clrkey, t->clearkey, t->len);
-		else
-			goto out;
-		/* alloc temp key buffer space */
-		tmpbuf = kmalloc(tmpbuflen, GFP_ATOMIC);
-		if (!tmpbuf) {
-			rc = -ENOMEM;
-			goto out;
+		switch (t->keytype) {
+		case PKEY_KEYTYPE_AES_128:
+		case PKEY_KEYTYPE_AES_192:
+		case PKEY_KEYTYPE_AES_256:
+			rc = nonccatokaes2pkey(t, protkey,
+					       protkeylen, protkeytype);
+			break;
+		case PKEY_KEYTYPE_ECC_P256:
+		case PKEY_KEYTYPE_ECC_P384:
+		case PKEY_KEYTYPE_ECC_P521:
+		case PKEY_KEYTYPE_ECC_ED25519:
+		case PKEY_KEYTYPE_ECC_ED448:
+			rc = nonccatokecc2pkey(t, protkey,
+					       protkeylen, protkeytype);
+			break;
+		default:
+			DEBUG_ERR("%s unknown/unsupported non cca clear key type %u\n",
+				  __func__, t->keytype);
+			return -EINVAL;
 		}
-		/* try direct way with the PCKMO instruction */
-		rc = pkey_clr2protkey(t->keytype, ckey.clrkey,
-				      protkey, protkeylen, protkeytype);
-		if (rc == 0)
-			break;
-		/* PCKMO failed, so try the CCA secure key way */
-		zcrypt_wait_api_operational();
-		rc = cca_clr2seckey(0xFFFF, 0xFFFF, t->keytype,
-				    ckey.clrkey, tmpbuf);
-		if (rc == 0)
-			rc = pkey_skey2pkey(tmpbuf,
-					    protkey, protkeylen, protkeytype);
-		if (rc == 0)
-			break;
-		/* if the CCA way also failed, let's try via EP11 */
-		rc = pkey_clr2ep11key(ckey.clrkey, t->len,
-				      tmpbuf, &tmpbuflen);
-		if (rc == 0)
-			rc = pkey_ep11key2pkey(tmpbuf,
-					       protkey, protkeylen, protkeytype);
-		/* now we should really have an protected key */
-		DEBUG_ERR("%s unable to build protected key from clear",
-			  __func__);
 		break;
 	}
 	case TOKVER_EP11_AES: {
···
 	default:
 		DEBUG_ERR("%s unknown/unsupported non-CCA token version %d\n",
 			  __func__, hdr->version);
-		rc = -EINVAL;
 	}
 
 out:
-	kfree(tmpbuf);
 	return rc;
 }
 
···
 
 static void *_copy_key_from_user(void __user *ukey, size_t keylen)
 {
-	if (!ukey || keylen < MINKEYBLOBSIZE || keylen > KEYBLOBBUFSIZE)
+	if (!ukey || keylen < MINKEYBLOBBUFSIZE || keylen > KEYBLOBBUFSIZE)
 		return ERR_PTR(-EINVAL);
 
 	return memdup_user(ukey, keylen);