[PATCH v5] mmc: host: sdhci-msm: Add support for wrapped keys

[Neeraj Soni]

Add the wrapped key support for sdhci-msm by implementing the needed
methods in struct blk_crypto_ll_ops and setting the appropriate flag in
blk_crypto_profile::key_types_supported.

Tested on SC7280 eMMC variant.

How to test:

Use the "v1.3.0" tag from https://github.com/google/fscryptctl and build
fscryptctl that supports generating wrapped keys.

Enable the following config options:
CONFIG_BLK_INLINE_ENCRYPTION=y
CONFIG_QCOM_INLINE_CRYPTO_ENGINE=y
CONFIG_FS_ENCRYPTION_INLINE_CRYPT=y
CONFIG_MMC_CRYPTO=y

Enable "qcom_ice.use_wrapped_keys" via kernel command line.

$ mkfs.ext4 -F -O encrypt,stable_inodes /dev/disk/by-partlabel/vm-data
$ mount /dev/disk/by-partlabel/vm-data -o inlinecrypt /mnt
$ fscryptctl generate_hw_wrapped_key /dev/disk/by-partlabel/vm-data > /mnt/key.longterm
$ fscryptctl prepare_hw_wrapped_key /dev/disk/by-partlabel/vm-data < /mnt/key.longterm > /tmp/key.ephemeral
$ KEYID=$(fscryptctl add_key --hw-wrapped-key < /tmp/key.ephemeral /mnt)
$ rm -rf /mnt/dir
$ mkdir /mnt/dir
$ fscryptctl set_policy --iv-ino-lblk-32 "$KEYID" /mnt/dir
$ dmesg > /mnt/dir/test.txt
$ sync

Reboot the board

$ mount /dev/disk/by-partlabel/vm-data -o inlinecrypt /mnt
$ ls /mnt/dir # File should be encrypted
$ fscryptctl prepare_hw_wrapped_key /dev/disk/by-partlabel/vm-data < /mnt/key.longterm > /tmp/key.ephemeral
$ KEYID=$(fscryptctl add_key --hw-wrapped-key < /tmp/key.ephemeral /mnt)
$ fscryptctl set_policy --iv-ino-lblk-32 "$KEYID" /mnt/dir
$ cat /mnt/dir/test.txt # File should now be decrypted

Tested-by: Wenjia Zhang <wenjia.zhang@xxxxxxxxxxxxxxxx>
Signed-off-by: Neeraj Soni <neeraj.soni@xxxxxxxxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>

---
This is a reworked version of the patchset
https://lore.kernel.org/all/20241101031539.13285-1-quic_spuppala@xxxxxxxxxxx/
that was sent by Seshu Madhavi Puppala.

My changes rebase it to use the custom crypto profile support.

Changes in v5:
- Rebased on mmc-next.

Changes in v4:
- Updated the link for fscryptctl tool in commit message to "https://github.com/google/fscryptctl";.
- Aligned the indentation at few places.
- Unwrapped few lines of code.

Changes in v3:
- Updated commit message with test details and moved "Signed-off-by" above the
  scissors line.

Changes in v2:
- Updated commit message for clarity.

Changes in v1:
- Added initial support for wrapped keys.
---
 drivers/mmc/host/sdhci-msm.c | 42 +++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index da356627d9de..b4131b12df56 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -1944,7 +1944,7 @@ static int sdhci_msm_ice_init(struct sdhci_msm_host *msm_host,
 
 	profile->ll_ops = sdhci_msm_crypto_ops;
 	profile->max_dun_bytes_supported = 4;
-	profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW;
+	profile->key_types_supported = qcom_ice_get_supported_key_type(ice);
 	profile->dev = dev;
 
 	/*
@@ -2024,6 +2024,42 @@ static int sdhci_msm_ice_keyslot_evict(struct blk_crypto_profile *profile,
 	return qcom_ice_evict_key(msm_host->ice, slot);
 }
 
+static int sdhci_msm_ice_derive_sw_secret(struct blk_crypto_profile *profile,
+					  const u8 *eph_key, size_t eph_key_size,
+					  u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE])
+{
+	struct sdhci_msm_host *msm_host = sdhci_msm_host_from_crypto_profile(profile);
+
+	return qcom_ice_derive_sw_secret(msm_host->ice, eph_key, eph_key_size,
+					 sw_secret);
+}
+
+static int sdhci_msm_ice_import_key(struct blk_crypto_profile *profile,
+				    const u8 *raw_key, size_t raw_key_size,
+				    u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE])
+{
+	struct sdhci_msm_host *msm_host = sdhci_msm_host_from_crypto_profile(profile);
+
+	return qcom_ice_import_key(msm_host->ice, raw_key, raw_key_size, lt_key);
+}
+
+static int sdhci_msm_ice_generate_key(struct blk_crypto_profile *profile,
+				      u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE])
+{
+	struct sdhci_msm_host *msm_host = sdhci_msm_host_from_crypto_profile(profile);
+
+	return qcom_ice_generate_key(msm_host->ice, lt_key);
+}
+
+static int sdhci_msm_ice_prepare_key(struct blk_crypto_profile *profile,
+				     const u8 *lt_key, size_t lt_key_size,
+				     u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE])
+{
+	struct sdhci_msm_host *msm_host = sdhci_msm_host_from_crypto_profile(profile);
+
+	return qcom_ice_prepare_key(msm_host->ice, lt_key, lt_key_size, eph_key);
+}
+
 static void sdhci_msm_non_cqe_ice_init(struct sdhci_host *host)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -2089,6 +2125,10 @@ static void sdhci_msm_request(struct mmc_host *mmc, struct mmc_request *mrq)
 static const struct blk_crypto_ll_ops sdhci_msm_crypto_ops = {
 	.keyslot_program	= sdhci_msm_ice_keyslot_program,
 	.keyslot_evict		= sdhci_msm_ice_keyslot_evict,
+	.derive_sw_secret	= sdhci_msm_ice_derive_sw_secret,
+	.import_key		= sdhci_msm_ice_import_key,
+	.generate_key		= sdhci_msm_ice_generate_key,
+	.prepare_key		= sdhci_msm_ice_prepare_key,
 };
 
 #else /* CONFIG_MMC_CRYPTO */
-- 
2.34.1