Re: [PATCH v4] mmc: host: sdhci-msm: Add support for wrapped keys

[Eric Biggers <ebiggers@kernel.org>]

On Fri, Jan 02, 2026 at 06:10:18PM +0530, Neeraj Soni wrote:
> 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@oss.qualcomm.com>
> Signed-off-by: Neeraj Soni <neeraj.soni@oss.qualcomm.com>

Reviewed-by: Eric Biggers <ebiggers@kernel.org>

- Eric