Re: [PATCH v4 05/15] soc: qcom: ice: support for hardware wrapped keys

Om Prakash Singh <quic_omprsing@xxxxxxxxxxx> · Tue, 6 Feb 2024 00:08:28 +0530

On 1/28/2024 4:44 AM, Gaurav Kashyap wrote:
Now that HWKM support is added to ICE, extend the ICE
driver to support hardware wrapped keys programming coming
in from the storage controllers (ufs and emmc). This is
similar to standard keys where the call is forwarded to
Trustzone, however certain wrapped key and HWKM specific
actions has to be performed around the SCM calls.

Derive software secret support is also added by forwarding the
call to the corresponding scm api.

Signed-off-by: Gaurav Kashyap <quic_gaurkash@xxxxxxxxxxx>
Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
Reviewed-by: Om Prakash Singh <quic_omprsing@xxxxxxxxxxx>

  drivers/soc/qcom/ice.c | 119 +++++++++++++++++++++++++++++++++++++----
  include/soc/qcom/ice.h |   4 ++
  2 files changed, 112 insertions(+), 11 deletions(-)

diff --git a/drivers/soc/qcom/ice.c b/drivers/soc/qcom/ice.c
index c718e8153b23..c3b852269dca 100644
--- a/drivers/soc/qcom/ice.c
+++ b/drivers/soc/qcom/ice.c
@@ -27,6 +27,8 @@
  #define QCOM_ICE_REG_BIST_STATUS		0x0070
  #define QCOM_ICE_REG_ADVANCED_CONTROL		0x1000
  #define QCOM_ICE_REG_CONTROL			0x0
+#define QCOM_ICE_LUT_KEYS_CRYPTOCFG_R16		0x4040
+
  /* QCOM ICE HWKM registers */
  #define QCOM_ICE_REG_HWKM_TZ_KM_CTL			0x1000
  #define QCOM_ICE_REG_HWKM_TZ_KM_STATUS			0x1004
@@ -48,6 +50,8 @@
  #define QCOM_ICE_FORCE_HW_KEY0_SETTING_MASK	0x2
  #define QCOM_ICE_FORCE_HW_KEY1_SETTING_MASK	0x4
  
+#define QCOM_ICE_LUT_KEYS_CRYPTOCFG_OFFSET	0x80
+
  #define QCOM_ICE_HWKM_REG_OFFSET	0x8000
  #define HWKM_OFFSET(reg)		((reg) + QCOM_ICE_HWKM_REG_OFFSET)
  
@@ -68,6 +72,16 @@ struct qcom_ice {
  	bool hwkm_init_complete;
  };
  
+union crypto_cfg {
+	__le32 regval;
+	struct {
+		u8 dusize;
+		u8 capidx;
+		u8 reserved;
+		u8 cfge;
+	};
+};
+
  static bool qcom_ice_check_supported(struct qcom_ice *ice)
  {
  	u32 regval = qcom_ice_readl(ice, QCOM_ICE_REG_VERSION);
@@ -273,6 +287,51 @@ int qcom_ice_suspend(struct qcom_ice *ice)
  }
  EXPORT_SYMBOL_GPL(qcom_ice_suspend);
  
+/*
+ * HW dictates the internal mapping between the ICE and HWKM slots,
+ * which are different for different versions, make the translation
+ * here. For v1 however, the translation is done in trustzone.
+ */
+static int translate_hwkm_slot(struct qcom_ice *ice, int slot)
+{
+	return (ice->hwkm_version == 1) ? slot : (slot * 2);
+}
+
+static int qcom_ice_program_wrapped_key(struct qcom_ice *ice,
+					const struct blk_crypto_key *key,
+					u8 data_unit_size, int slot)
+{
+	union crypto_cfg cfg;
+	int hwkm_slot;
+	int err;
+
+	hwkm_slot = translate_hwkm_slot(ice, slot);
+
+	memset(&cfg, 0, sizeof(cfg));
+	cfg.dusize = data_unit_size;
+	cfg.capidx = QCOM_SCM_ICE_CIPHER_AES_256_XTS;
+	cfg.cfge = 0x80;
+
+	/* Clear CFGE */
+	qcom_ice_writel(ice, 0x0, QCOM_ICE_LUT_KEYS_CRYPTOCFG_R16 +
+				  QCOM_ICE_LUT_KEYS_CRYPTOCFG_OFFSET * slot);
+
+	/* Call trustzone to program the wrapped key using hwkm */
+	err = qcom_scm_ice_set_key(hwkm_slot, key->raw, key->size,
+				   QCOM_SCM_ICE_CIPHER_AES_256_XTS, data_unit_size);
+	if (err) {
+		pr_err("%s:SCM call Error: 0x%x slot %d\n", __func__, err,
+		       slot);
+		return err;
+	}
+
+	/* Enable CFGE after programming key */
+	qcom_ice_writel(ice, cfg.regval, QCOM_ICE_LUT_KEYS_CRYPTOCFG_R16 +
+					 QCOM_ICE_LUT_KEYS_CRYPTOCFG_OFFSET * slot);
+
+	return err;
+}
+
  int qcom_ice_program_key(struct qcom_ice *ice,
  			 u8 algorithm_id, u8 key_size,
  			 const struct blk_crypto_key *bkey,
@@ -288,24 +347,39 @@ int qcom_ice_program_key(struct qcom_ice *ice,
  
  	/* Only AES-256-XTS has been tested so far. */
  	if (algorithm_id != QCOM_ICE_CRYPTO_ALG_AES_XTS ||
-	    key_size != QCOM_ICE_CRYPTO_KEY_SIZE_256) {
+	    (key_size != QCOM_ICE_CRYPTO_KEY_SIZE_256 &&
+	    key_size != QCOM_ICE_CRYPTO_KEY_SIZE_WRAPPED)) {
  		dev_err_ratelimited(dev,
  				    "Unhandled crypto capability; algorithm_id=%d, key_size=%d\n",
  				    algorithm_id, key_size);
  		return -EINVAL;
  	}
  
-	memcpy(key.bytes, bkey->raw, AES_256_XTS_KEY_SIZE);
-
-	/* The SCM call requires that the key words are encoded in big endian */
-	for (i = 0; i < ARRAY_SIZE(key.words); i++)
-		__cpu_to_be32s(&key.words[i]);
+	if (bkey->crypto_cfg.key_type == BLK_CRYPTO_KEY_TYPE_HW_WRAPPED) {
+		/* It is expected that HWKM init has completed before programming wrapped keys */
+		if (!ice->use_hwkm || !ice->hwkm_init_complete) {
+			dev_err_ratelimited(dev, "HWKM not currently used or initialized\n");
+			return -EINVAL;
+		}
+		err = qcom_ice_program_wrapped_key(ice, bkey, data_unit_size,
+						   slot);
+	} else {
+		if (bkey->size != QCOM_ICE_CRYPTO_KEY_SIZE_256)
+			dev_err_ratelimited(dev,
+					    "Incorrect key size; bkey->size=%d\n",
+					    algorithm_id);
+		return -EINVAL;
+		memcpy(key.bytes, bkey->raw, AES_256_XTS_KEY_SIZE);
  
-	err = qcom_scm_ice_set_key(slot, key.bytes, AES_256_XTS_KEY_SIZE,
-				   QCOM_SCM_ICE_CIPHER_AES_256_XTS,
-				   data_unit_size);
+		/* The SCM call requires that the key words are encoded in big endian */
+		for (i = 0; i < ARRAY_SIZE(key.words); i++)
+			__cpu_to_be32s(&key.words[i]);
  
-	memzero_explicit(&key, sizeof(key));
+		err = qcom_scm_ice_set_key(slot, key.bytes, AES_256_XTS_KEY_SIZE,
+					   QCOM_SCM_ICE_CIPHER_AES_256_XTS,
+					   data_unit_size);
+		memzero_explicit(&key, sizeof(key));
+	}
  
  	return err;
  }
@@ -313,7 +387,21 @@ EXPORT_SYMBOL_GPL(qcom_ice_program_key);
  
  int qcom_ice_evict_key(struct qcom_ice *ice, int slot)
  {
-	return qcom_scm_ice_invalidate_key(slot);
+	int hwkm_slot = slot;
+
+	if (ice->use_hwkm) {
+		hwkm_slot = translate_hwkm_slot(ice, slot);
+	/*
+	 * Ignore calls to evict key when HWKM is supported and hwkm init
+	 * is not yet done. This is to avoid the clearing all slots call
+	 * during a storage reset when ICE is still in legacy mode. HWKM slave
+	 * in ICE takes care of zeroing out the keytable on reset.
+	 */
+		if (!ice->hwkm_init_complete)
+			return 0;
+	}
+
+	return qcom_scm_ice_invalidate_key(hwkm_slot);
  }
  EXPORT_SYMBOL_GPL(qcom_ice_evict_key);
  
@@ -323,6 +411,15 @@ bool qcom_ice_hwkm_supported(struct qcom_ice *ice)
  }
  EXPORT_SYMBOL_GPL(qcom_ice_hwkm_supported);
  
+int qcom_ice_derive_sw_secret(struct qcom_ice *ice, const u8 wkey[],
+			      unsigned int wkey_size,
+			      u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE])
+{
+	return qcom_scm_derive_sw_secret(wkey, wkey_size,
+					 sw_secret, BLK_CRYPTO_SW_SECRET_SIZE);
+}
+EXPORT_SYMBOL_GPL(qcom_ice_derive_sw_secret);
+
  static struct qcom_ice *qcom_ice_create(struct device *dev,
  					void __iomem *base)
  {
diff --git a/include/soc/qcom/ice.h b/include/soc/qcom/ice.h
index 1f52e82e3e1c..dabe0d3a1fd0 100644
--- a/include/soc/qcom/ice.h
+++ b/include/soc/qcom/ice.h
@@ -17,6 +17,7 @@ enum qcom_ice_crypto_key_size {
  	QCOM_ICE_CRYPTO_KEY_SIZE_192		= 0x2,
  	QCOM_ICE_CRYPTO_KEY_SIZE_256		= 0x3,
  	QCOM_ICE_CRYPTO_KEY_SIZE_512		= 0x4,
+	QCOM_ICE_CRYPTO_KEY_SIZE_WRAPPED	= 0x5,
  };
  
  enum qcom_ice_crypto_alg {
@@ -35,5 +36,8 @@ int qcom_ice_program_key(struct qcom_ice *ice,
  			 u8 data_unit_size, int slot);
  int qcom_ice_evict_key(struct qcom_ice *ice, int slot);
  bool qcom_ice_hwkm_supported(struct qcom_ice *ice);
+int qcom_ice_derive_sw_secret(struct qcom_ice *ice, const u8 wkey[],
+			      unsigned int wkey_size,
+			      u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]);
  struct qcom_ice *of_qcom_ice_get(struct device *dev);
  #endif /* __QCOM_ICE_H__ */







