s390/pkey: Introduce pkey kernel module

This patch introcudes a new kernel module pkey which is providing
protected key handling and management functions. The pkey API is
available within the kernel for other s390 specific code to create
and manage protected keys. Additionally the functions are exported
to user space via IOCTL calls. The implementation makes extensive
use of functions provided by the zcrypt device driver. For
generating protected keys from secure keys there is also a CEX
coprocessor card needed.
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/configs/default_defconfig

@@ -678,6 +678,7 @@ CONFIG_CRYPTO_USER_API_SKCIPHER=m
 CONFIG_CRYPTO_USER_API_RNG=m
 CONFIG_CRYPTO_USER_API_AEAD=m
 CONFIG_ZCRYPT=m
+CONFIG_PKEY=m
 CONFIG_CRYPTO_SHA1_S390=m
 CONFIG_CRYPTO_SHA256_S390=m
 CONFIG_CRYPTO_SHA512_S390=m

arch/s390/configs/performance_defconfig

@@ -628,6 +628,7 @@ CONFIG_CRYPTO_USER_API_SKCIPHER=m
 CONFIG_CRYPTO_USER_API_RNG=m
 CONFIG_CRYPTO_USER_API_AEAD=m
 CONFIG_ZCRYPT=m
+CONFIG_PKEY=m
 CONFIG_CRYPTO_SHA1_S390=m
 CONFIG_CRYPTO_SHA256_S390=m
 CONFIG_CRYPTO_SHA512_S390=m

arch/s390/defconfig

@@ -229,6 +229,7 @@ CONFIG_CRYPTO_USER_API_HASH=m
 CONFIG_CRYPTO_USER_API_SKCIPHER=m
 CONFIG_CRYPTO_USER_API_RNG=m
 CONFIG_ZCRYPT=m
+CONFIG_PKEY=m
 CONFIG_CRYPTO_SHA1_S390=m
 CONFIG_CRYPTO_SHA256_S390=m
 CONFIG_CRYPTO_SHA512_S390=m

arch/s390/include/asm/pkey.h

+/*
+ * Kernelspace interface to the pkey device driver
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author: Harald Freudenberger <freude@de.ibm.com>
+ *
+ */
+
+#ifndef _KAPI_PKEY_H
+#define _KAPI_PKEY_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+#include <uapi/asm/pkey.h>
+
+/*
+ * Generate (AES) random secure key.
+ * @param cardnr may be -1 (use default card)
+ * @param domain may be -1 (use default domain)
+ * @param keytype one of the PKEY_KEYTYPE values
+ * @param seckey pointer to buffer receiving the secure key
+ * @return 0 on success, negative errno value on failure
+ */
+int pkey_genseckey(__u16 cardnr, __u16 domain,
+		   __u32 keytype, struct pkey_seckey *seckey);
+
+/*
+ * Generate (AES) secure key with given key value.
+ * @param cardnr may be -1 (use default card)
+ * @param domain may be -1 (use default domain)
+ * @param keytype one of the PKEY_KEYTYPE values
+ * @param clrkey pointer to buffer with clear key data
+ * @param seckey pointer to buffer receiving the secure key
+ * @return 0 on success, negative errno value on failure
+ */
+int pkey_clr2seckey(__u16 cardnr, __u16 domain, __u32 keytype,
+		    const struct pkey_clrkey *clrkey,
+		    struct pkey_seckey *seckey);
+
+/*
+ * Derive (AES) proteced key from the (AES) secure key blob.
+ * @param cardnr may be -1 (use default card)
+ * @param domain may be -1 (use default domain)
+ * @param seckey pointer to buffer with the input secure key
+ * @param protkey pointer to buffer receiving the protected key and
+ *	  additional info (type, length)
+ * @return 0 on success, negative errno value on failure
+ */
+int pkey_sec2protkey(__u16 cardnr, __u16 domain,
+		     const struct pkey_seckey *seckey,
+		     struct pkey_protkey *protkey);
+
+/*
+ * Derive (AES) protected key from a given clear key value.
+ * @param keytype one of the PKEY_KEYTYPE values
+ * @param clrkey pointer to buffer with clear key data
+ * @param protkey pointer to buffer receiving the protected key and
+ *	  additional info (type, length)
+ * @return 0 on success, negative errno value on failure
+ */
+int pkey_clr2protkey(__u32 keytype,
+		     const struct pkey_clrkey *clrkey,
+		     struct pkey_protkey *protkey);
+
+/*
+ * Search for a matching crypto card based on the Master Key
+ * Verification Pattern provided inside a secure key.
+ * @param seckey pointer to buffer with the input secure key
+ * @param cardnr pointer to cardnr, receives the card number on success
+ * @param domain pointer to domain, receives the domain number on success
+ * @param verify if set, always verify by fetching verification pattern
+ *	  from card
+ * @return 0 on success, negative errno value on failure. If no card could be
+ *	   found, -ENODEV is returned.
+ */
+int pkey_findcard(const struct pkey_seckey *seckey,
+		  __u16 *cardnr, __u16 *domain, int verify);
+
+/*
+ * Find card and transform secure key to protected key.
+ * @param seckey pointer to buffer with the input secure key
+ * @param protkey pointer to buffer receiving the protected key and
+ *	  additional info (type, length)
+ * @return 0 on success, negative errno value on failure
+ */
+int pkey_skey2pkey(const struct pkey_seckey *seckey,
+		   struct pkey_protkey *protkey);
+
+#endif /* _KAPI_PKEY_H */

arch/s390/include/uapi/asm/Kbuild

@@ -24,6 +24,7 @@ header-y += mman.h
 header-y += monwriter.h
 header-y += msgbuf.h
 header-y += param.h
+header-y += pkey.h
 header-y += poll.h
 header-y += posix_types.h
 header-y += ptrace.h

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

+/*
+ * Userspace interface to the pkey device driver
+ *
+ * Copyright IBM Corp. 2017
+ *
+ * Author: Harald Freudenberger <freude@de.ibm.com>
+ *
+ */
+
+#ifndef _UAPI_PKEY_H
+#define _UAPI_PKEY_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/*
+ * Ioctl calls supported by the pkey device driver
+ */
+
+#define PKEY_IOCTL_MAGIC 'p'
+
+#define SECKEYBLOBSIZE	64     /* secure key blob size is always 64 bytes */
+#define MAXPROTKEYSIZE	64  /* a protected key blob may be up to 64 bytes */
+#define MAXCLRKEYSIZE	32     /* a clear key value may be up to 32 bytes */
+
+/* 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
+
+/* Struct to hold a secure key blob */
+struct pkey_seckey {
+	__u8  seckey[SECKEYBLOBSIZE];		  /* the secure key blob */
+};
+
+/* Struct to hold protected key and length info */
+struct pkey_protkey {
+	__u32 type;	     /* key type, one of the PKEY_KEYTYPE values */
+	__u32 len;		/* bytes actually stored in protkey[]	 */
+	__u8  protkey[MAXPROTKEYSIZE];	       /* the protected key blob */
+};
+
+/* Struct to hold a clear key value */
+struct pkey_clrkey {
+	__u8  clrkey[MAXCLRKEYSIZE]; /* 16, 24, or 32 byte clear key value */
+};
+
+/*
+ * Generate secure key
+ */
+struct pkey_genseck {
+	__u16 cardnr;		    /* in: card to use or FFFF for any	 */
+	__u16 domain;		    /* in: domain or FFFF for any	 */
+	__u32 keytype;		    /* in: key type to generate		 */
+	struct pkey_seckey seckey;  /* out: the secure key blob		 */
+};
+#define PKEY_GENSECK _IOWR(PKEY_IOCTL_MAGIC, 0x01, struct pkey_genseck)
+
+/*
+ * Construct secure key from clear key value
+ */
+struct pkey_clr2seck {
+	__u16 cardnr;		    /* in: card to use or FFFF for any	 */
+	__u16 domain;		    /* in: domain or FFFF for any	 */
+	__u32 keytype;		    /* in: key type to generate		 */
+	struct pkey_clrkey clrkey;  /* in: the clear key value		 */
+	struct pkey_seckey seckey;  /* out: the secure key blob		 */
+};
+#define PKEY_CLR2SECK _IOWR(PKEY_IOCTL_MAGIC, 0x02, struct pkey_clr2seck)
+
+/*
+ * Fabricate protected key from a secure key
+ */
+struct pkey_sec2protk {
+	__u16 cardnr;		     /* in: card to use or FFFF for any   */
+	__u16 domain;		     /* in: domain or FFFF for any	  */
+	struct pkey_seckey seckey;   /* in: the secure key blob		  */
+	struct pkey_protkey protkey; /* out: the protected key		  */
+};
+#define PKEY_SEC2PROTK _IOWR(PKEY_IOCTL_MAGIC, 0x03, struct pkey_sec2protk)
+
+/*
+ * Fabricate protected key from an clear key value
+ */
+struct pkey_clr2protk {
+	__u32 keytype;		     /* in: key type to generate	  */
+	struct pkey_clrkey clrkey;   /* in: the clear key value		  */
+	struct pkey_protkey protkey; /* out: the protected key		  */
+};
+#define PKEY_CLR2PROTK _IOWR(PKEY_IOCTL_MAGIC, 0x04, struct pkey_clr2protk)
+
+/*
+ * Search for matching crypto card based on the Master Key
+ * Verification Pattern provided inside a secure key.
+ */
+struct pkey_findcard {
+	struct pkey_seckey seckey;	       /* in: the secure key blob */
+	__u16  cardnr;			       /* out: card number	  */
+	__u16  domain;			       /* out: domain number	  */
+};
+#define PKEY_FINDCARD _IOWR(PKEY_IOCTL_MAGIC, 0x05, struct pkey_findcard)
+
+/*
+ * Combined together: findcard + sec2prot
+ */
+struct pkey_skey2pkey {
+	struct pkey_seckey seckey;   /* in: the secure key blob		  */
+	struct pkey_protkey protkey; /* out: the protected key		  */
+};
+#define PKEY_SKEY2PKEY _IOWR(PKEY_IOCTL_MAGIC, 0x06, struct pkey_skey2pkey)
+
+#endif /* _UAPI_PKEY_H */

drivers/crypto/Kconfig

@@ -73,6 +73,22 @@ config ZCRYPT
 	  + Crypto Express 2,3,4 or 5 Accelerator (CEXxA)
 	  + Crypto Express 4 or 5 EP11 Coprocessor (CEXxP)
 
+config PKEY
+	tristate "Kernel API for protected key handling"
+	depends on S390
+	depends on ZCRYPT
+	help
+	  With this option enabled the pkey kernel module provides an API
+	  for creation and handling of protected keys. Other parts of the
+	  kernel or userspace applications may use these functions.
+
+	  Select this option if you want to enable the kernel and userspace
+	  API for proteced key handling.
+
+	  Please note that creation of protected keys from secure keys
+	  requires to have at least one CEX card in coprocessor mode
+	  available at runtime.
+
 config CRYPTO_SHA1_S390
 	tristate "SHA1 digest algorithm"
 	depends on S390

drivers/s390/crypto/Makefile

@@ -10,3 +10,7 @@ zcrypt-objs += zcrypt_msgtype6.o zcrypt_msgtype50.o
 obj-$(CONFIG_ZCRYPT) += zcrypt.o
 # adapter drivers depend on ap.o and zcrypt.o
 obj-$(CONFIG_ZCRYPT) += zcrypt_pcixcc.o zcrypt_cex2a.o zcrypt_cex4.o
+
+# pkey kernel module
+pkey-objs := pkey_api.o
+obj-$(CONFIG_PKEY) += pkey.o