keys, trusted: select hash algorithm for TPM2 chips

Added 'hash=' option for selecting the hash algorithm for add_key()
syscall and documentation for it.

Added entry for sm3-256 to the following tables in order to support
TPM_ALG_SM3_256:

* hash_algo_name
* hash_digest_size

Includes support for the following hash algorithms:

* sha1
* sha256
* sha384
* sha512
* sm3-256
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>

Documentation/security/keys-trusted-encrypted.txt

@@ -38,6 +38,9 @@ Usage:
        pcrlock=	  pcr number to be extended to "lock" blob
        migratable= 0|1 indicating permission to reseal to new PCR values,
                    default 1 (resealing allowed)
+       hash=      hash algorithm name as a string. For TPM 1.x the only
+                  allowed value is sha1. For TPM 2.x the allowed values
+		  are sha1, sha256, sha384, sha512 and sm3-256.
 
 "keyctl print" returns an ascii hex copy of the sealed key, which is in standard
 TPM_STORED_DATA format.  The key length for new keys are always in bytes.

crypto/hash_info.c

@@ -31,6 +31,7 @@ const char *const hash_algo_name[HASH_ALGO__LAST] = {
 	[HASH_ALGO_TGR_128]	= "tgr128",
 	[HASH_ALGO_TGR_160]	= "tgr160",
 	[HASH_ALGO_TGR_192]	= "tgr192",
+	[HASH_ALGO_SM3_256]	= "sm3-256",
 };
 EXPORT_SYMBOL_GPL(hash_algo_name);
 
@@ -52,5 +53,6 @@ const int hash_digest_size[HASH_ALGO__LAST] = {
 	[HASH_ALGO_TGR_128]	= TGR128_DIGEST_SIZE,
 	[HASH_ALGO_TGR_160]	= TGR160_DIGEST_SIZE,
 	[HASH_ALGO_TGR_192]	= TGR192_DIGEST_SIZE,
+	[HASH_ALGO_SM3_256]	= SM3256_DIGEST_SIZE,
 };
 EXPORT_SYMBOL_GPL(hash_digest_size);

drivers/char/tpm/tpm.h

@@ -83,16 +83,20 @@ enum tpm2_structures {
 };
 
 enum tpm2_return_codes {
-	TPM2_RC_INITIALIZE	= 0x0100,
-	TPM2_RC_TESTING		= 0x090A,
+	TPM2_RC_HASH		= 0x0083, /* RC_FMT1 */
+	TPM2_RC_INITIALIZE	= 0x0100, /* RC_VER1 */
 	TPM2_RC_DISABLED	= 0x0120,
+	TPM2_RC_TESTING		= 0x090A, /* RC_WARN */
 };
 
 enum tpm2_algorithms {
 	TPM2_ALG_SHA1		= 0x0004,
 	TPM2_ALG_KEYEDHASH	= 0x0008,
 	TPM2_ALG_SHA256		= 0x000B,
-	TPM2_ALG_NULL		= 0x0010
+	TPM2_ALG_SHA384		= 0x000C,
+	TPM2_ALG_SHA512		= 0x000D,
+	TPM2_ALG_NULL		= 0x0010,
+	TPM2_ALG_SM3_256	= 0x0012,
 };
 
 enum tpm2_command_codes {

drivers/char/tpm/tpm2-cmd.c

@@ -16,6 +16,7 @@
  */
 
 #include "tpm.h"
+#include <crypto/hash_info.h>
 #include <keys/trusted-type.h>
 
 enum tpm2_object_attributes {
@@ -104,6 +105,19 @@ struct tpm2_cmd {
 	union tpm2_cmd_params	params;
 } __packed;
 
+struct tpm2_hash {
+	unsigned int crypto_id;
+	unsigned int tpm_id;
+};
+
+static struct tpm2_hash tpm2_hash_map[] = {
+	{HASH_ALGO_SHA1, TPM2_ALG_SHA1},
+	{HASH_ALGO_SHA256, TPM2_ALG_SHA256},
+	{HASH_ALGO_SHA384, TPM2_ALG_SHA384},
+	{HASH_ALGO_SHA512, TPM2_ALG_SHA512},
+	{HASH_ALGO_SM3_256, TPM2_ALG_SM3_256},
+};
+
 /*
  * Array with one entry per ordinal defining the maximum amount
  * of time the chip could take to return the result. The values
@@ -429,8 +443,20 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 {
 	unsigned int blob_len;
 	struct tpm_buf buf;
+	u32 hash;
+	int i;
 	int rc;
 
+	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
+		if (options->hash == tpm2_hash_map[i].crypto_id) {
+			hash = tpm2_hash_map[i].tpm_id;
+			break;
+		}
+	}
+
+	if (i == ARRAY_SIZE(tpm2_hash_map))
+		return -EINVAL;
+
 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
 	if (rc)
 		return rc;
@@ -455,7 +481,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	tpm_buf_append_u16(&buf, 14);
 
 	tpm_buf_append_u16(&buf, TPM2_ALG_KEYEDHASH);
-	tpm_buf_append_u16(&buf, TPM2_ALG_SHA256);
+	tpm_buf_append_u16(&buf, hash);
 	tpm_buf_append_u32(&buf, TPM2_ATTR_USER_WITH_AUTH);
 	tpm_buf_append_u16(&buf, 0); /* policy digest size */
 	tpm_buf_append_u16(&buf, TPM2_ALG_NULL);
@@ -488,8 +514,12 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 out:
 	tpm_buf_destroy(&buf);
 
-	if (rc > 0)
-		rc = -EPERM;
+	if (rc > 0) {
+		if ((rc & TPM2_RC_HASH) == TPM2_RC_HASH)
+			rc = -EINVAL;
+		else
+			rc = -EPERM;
+	}
 
 	return rc;
 }

include/crypto/hash_info.h

@@ -34,6 +34,9 @@
 #define TGR160_DIGEST_SIZE 20
 #define TGR192_DIGEST_SIZE 24
 
+/* not defined in include/crypto/ */
+#define SM3256_DIGEST_SIZE 32
+
 extern const char *const hash_algo_name[HASH_ALGO__LAST];
 extern const int hash_digest_size[HASH_ALGO__LAST];
 

include/keys/trusted-type.h

@@ -36,6 +36,7 @@ struct trusted_key_options {
 	uint32_t pcrinfo_len;
 	unsigned char pcrinfo[MAX_PCRINFO_SIZE];
 	int pcrlock;
+	uint32_t hash;
 };
 
 extern struct key_type key_type_trusted;

include/uapi/linux/hash_info.h

@@ -31,6 +31,7 @@ enum hash_algo {
 	HASH_ALGO_TGR_128,
 	HASH_ALGO_TGR_160,
 	HASH_ALGO_TGR_192,
+	HASH_ALGO_SM3_256,
 	HASH_ALGO__LAST
 };
 

security/keys/Kconfig

@@ -54,6 +54,7 @@ config TRUSTED_KEYS
 	select CRYPTO
 	select CRYPTO_HMAC
 	select CRYPTO_SHA1
+	select CRYPTO_HASH_INFO
 	help
 	  This option provides support for creating, sealing, and unsealing
 	  keys in the kernel. Trusted keys are random number symmetric keys,

security/keys/trusted.c

@@ -11,6 +11,7 @@
  * See Documentation/security/keys-trusted-encrypted.txt
  */
 
+#include <crypto/hash_info.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -710,7 +711,8 @@ enum {
 	Opt_err = -1,
 	Opt_new, Opt_load, Opt_update,
 	Opt_keyhandle, Opt_keyauth, Opt_blobauth,
-	Opt_pcrinfo, Opt_pcrlock, Opt_migratable
+	Opt_pcrinfo, Opt_pcrlock, Opt_migratable,
+	Opt_hash,
 };
 
 static const match_table_t key_tokens = {
@@ -723,6 +725,7 @@ static const match_table_t key_tokens = {
 	{Opt_pcrinfo, "pcrinfo=%s"},
 	{Opt_pcrlock, "pcrlock=%s"},
 	{Opt_migratable, "migratable=%s"},
+	{Opt_hash, "hash=%s"},
 	{Opt_err, NULL}
 };
 
@@ -737,6 +740,14 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
 	unsigned long handle;
 	unsigned long lock;
 	unsigned long token_mask = 0;
+	int i;
+	int tpm2;
+
+	tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
+	if (tpm2 < 0)
+		return tpm2;
+
+	opt->hash = tpm2 ? HASH_ALGO_SHA256 : HASH_ALGO_SHA1;
 
 	while ((p = strsep(&c, " \t"))) {
 		if (*p == '\0' || *p == ' ' || *p == '\t')
@@ -790,6 +801,20 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
 				return -EINVAL;
 			opt->pcrlock = lock;
 			break;
+		case Opt_hash:
+			for (i = 0; i < HASH_ALGO__LAST; i++) {
+				if (!strcmp(args[0].from, hash_algo_name[i])) {
+					opt->hash = i;
+					break;
+				}
+			}
+			if (i == HASH_ALGO__LAST)
+				return -EINVAL;
+			if  (!tpm2 && i != HASH_ALGO_SHA1) {
+				pr_info("trusted_key: TPM 1.x only supports SHA-1.\n");
+				return -EINVAL;
+			}
+			break;
 		default:
 			return -EINVAL;
 		}