[RFC PATCH HBK: 1/8] keys-trusted: new cmd line option added

[Pankaj Gupta <pankaj.gupta@xxxxxxx>]

Two changes are done:
- new cmd line option "hw" needs to be suffix, to generate the
  hw bound key.
  for ex:
   $:> keyctl add trusted <KEYNAME> 'new 32 hw' @s
   $:> keyctl add trusted <KEYNAME> 'load $(cat <KEY_BLOB_FILE_NAME>) hw' @s

- For "new", generating the hw bounded trusted key, updating the input key
  length as part of seal operation as well.

Signed-off-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
---
 include/keys/trusted-type.h               |  2 ++
 security/keys/trusted-keys/trusted_caam.c |  6 ++++++
 security/keys/trusted-keys/trusted_core.c | 14 ++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index 4eb64548a74f..064266b936c7 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -22,6 +22,7 @@
 #define MAX_BLOB_SIZE			512
 #define MAX_PCRINFO_SIZE		64
 #define MAX_DIGEST_SIZE			64
+#define HW_BOUND_KEY                    1
 
 struct trusted_key_payload {
 	struct rcu_head rcu;
@@ -29,6 +30,7 @@ struct trusted_key_payload {
 	unsigned int blob_len;
 	unsigned char migratable;
 	unsigned char old_format;
+	unsigned char is_hw_bound;
 	unsigned char key[MAX_KEY_SIZE + 1];
 	unsigned char blob[MAX_BLOB_SIZE];
 };
diff --git a/security/keys/trusted-keys/trusted_caam.c b/security/keys/trusted-keys/trusted_caam.c
index e3415c520c0a..fceb9a271c4d 100644
--- a/security/keys/trusted-keys/trusted_caam.c
+++ b/security/keys/trusted-keys/trusted_caam.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@xxxxxxxxxxxxxx>
+ * Copyright 2022 NXP, Pankaj Gupta <pankaj.gupta@xxxxxxx>
  */
 
 #include <keys/trusted_caam.h>
@@ -23,6 +24,7 @@ static int trusted_caam_seal(struct trusted_key_payload *p, char *datablob)
 		.input  = p->key,  .input_len   = p->key_len,
 		.output = p->blob, .output_len  = MAX_BLOB_SIZE,
 		.key_mod = KEYMOD, .key_mod_len = sizeof(KEYMOD) - 1,
+		.is_hw_bound = p->is_hw_bound,
 	};
 
 	ret = caam_encap_blob(blobifier, &info);
@@ -30,6 +32,9 @@ static int trusted_caam_seal(struct trusted_key_payload *p, char *datablob)
 		return ret;
 
 	p->blob_len = info.output_len;
+	if (p->is_hw_bound)
+		p->key_len = info.input_len;
+
 	return 0;
 }
 
@@ -40,6 +45,7 @@ static int trusted_caam_unseal(struct trusted_key_payload *p, char *datablob)
 		.input   = p->blob,  .input_len  = p->blob_len,
 		.output  = p->key,   .output_len = MAX_KEY_SIZE,
 		.key_mod = KEYMOD,  .key_mod_len = sizeof(KEYMOD) - 1,
+		.is_hw_bound = p->is_hw_bound,
 	};
 
 	ret = caam_decap_blob(blobifier, &info);
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
index c6fc50d67214..7f7cc2551b92 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -79,6 +79,8 @@ static int datablob_parse(char **datablob, struct trusted_key_payload *p)
 	int key_cmd;
 	char *c;
 
+	p->is_hw_bound = !HW_BOUND_KEY;
+
 	/* main command */
 	c = strsep(datablob, " \t");
 	if (!c)
@@ -94,6 +96,12 @@ static int datablob_parse(char **datablob, struct trusted_key_payload *p)
 		if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
 			return -EINVAL;
 		p->key_len = keylen;
+		/* second argument is to determine if tied to HW */
+		c = strsep(datablob, " \t");
+		if (c) {
+			if (strcmp(c, "hw") == 0)
+				p->is_hw_bound = HW_BOUND_KEY;
+		}
 		ret = Opt_new;
 		break;
 	case Opt_load:
@@ -107,6 +115,12 @@ static int datablob_parse(char **datablob, struct trusted_key_payload *p)
 		ret = hex2bin(p->blob, c, p->blob_len);
 		if (ret < 0)
 			return -EINVAL;
+		/* second argument is to determine if tied to HW */
+		c = strsep(datablob, " \t");
+		if (c) {
+			if (strcmp(c, "hw") == 0)
+				p->is_hw_bound = HW_BOUND_KEY;
+		}
 		ret = Opt_load;
 		break;
 	case Opt_update:
-- 
2.17.1