Re: [PATCH 05/10] scsi: ufs: prepare to support wrapped keys
From: Eric Biggers <ebiggers@kernel.org>
Date: 2021-12-14 01:27:02
Also in:
linux-arm-msm, linux-fscrypt, linux-mmc, linux-scsi
On Mon, Dec 06, 2021 at 02:57:20PM -0800, Gaurav Kashyap wrote:
Adds support in ufshcd-core for wrapped keys. 1. Change program key vop to support wrapped key sizes by using blk_crypto_key directly instead of using ufs_crypto_cfg which is not suitable for wrapped keys. 2. Add derive_sw_secret vop and derive_sw_secret crypto_profile op. Signed-off-by: Gaurav Kashyap <redacted> --- drivers/scsi/ufs/ufshcd-crypto.c | 52 +++++++++++++++++++++++++------- drivers/scsi/ufs/ufshcd.h | 9 +++++- 2 files changed, 49 insertions(+), 12 deletions(-)
There will be a build error if the patch series is applied just up to here, since this patch changes the prototype of ufs_hba_variant_ops::program_key but doesn't update ufs_qcom which implements it. Every intermediate step needs to be buildable, and that's more important than keeping changes to different drivers separate. So I recommend having one patch that does the program_key change, in both ufshcd-crypto.c and ufs-qcom-ice.c. Adding derive_sw_secret should be a separate patch, and maybe should be combined with the other new methods.
quoted hunk ↗ jump to hunk
diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c index 0ed82741f981..9d68621a0eb4 100644 --- a/drivers/scsi/ufs/ufshcd-crypto.c +++ b/drivers/scsi/ufs/ufshcd-crypto.c@@ -18,16 +18,23 @@ static const struct ufs_crypto_alg_entry { }; static int ufshcd_program_key(struct ufs_hba *hba, + const struct blk_crypto_key *key, const union ufs_crypto_cfg_entry *cfg, int slot) { int i; u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg); int err = 0; + bool evict = false; ufshcd_hold(hba, false); if (hba->vops && hba->vops->program_key) { - err = hba->vops->program_key(hba, cfg, slot); + if (!(cfg->config_enable & UFS_CRYPTO_CONFIGURATION_ENABLE)) + evict = true; + err = hba->vops->program_key(hba, key, slot, + cfg->data_unit_size, + cfg->crypto_cap_idx, + evict); goto out; }
This is a little weird because here we've already gone through the trouble of creating a 'union ufs_crypto_cfg_entry', only to throw it away in the ->program_key case and just use the original blk_crypto_key instead. I think that this should be refactored a bit to make it so that a 'ufs_crypto_cfg_entry' is only be initialized if program_key is not implemented. Also, note that 'struct blk_crypto_key' includes the data unit size. So there's no need to pass the data unit size as a separate argument to program_key.
+static int ufshcd_crypto_derive_sw_secret(struct blk_crypto_profile *profile,
+ const u8 *wrapped_key,
+ unsigned int wrapped_key_size,
+ u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE])
+{
+ struct ufs_hba *hba =
+ container_of(profile, struct ufs_hba, crypto_profile);
+
+ if (hba->vops && hba->vops->derive_secret)
+ return hba->vops->derive_secret(hba, wrapped_key,
+ wrapped_key_size, sw_secret);There's a weird double space here.
quoted hunk ↗ jump to hunk
@@ -190,7 +215,12 @@ int ufshcd_hba_init_crypto_capabilities(struct ufs_hba *hba) hba->crypto_profile.ll_ops = ufshcd_crypto_ops; /* UFS only supports 8 bytes for any DUN */ hba->crypto_profile.max_dun_bytes_supported = 8; - hba->crypto_profile.key_types_supported = BLK_CRYPTO_KEY_TYPE_STANDARD; + if (hba->hw_wrapped_keys_supported) + hba->crypto_profile.key_types_supported = + BLK_CRYPTO_KEY_TYPE_HW_WRAPPED; + else + hba->crypto_profile.key_types_supported = + BLK_CRYPTO_KEY_TYPE_STANDARD;
"hw_wrapped_keys_supported" is confusing because it doesn't just mean that wrapped keys are supported, but also that standard keys are *not* supported. "use_hw_wrapped_keys" would be clearer. However, given that wrapped keys aren't specified by the UFS standard, I think this better belongs as a bit in hba->quirks, like UFSHCD_QUIRK_USES_WRAPPED_CRYPTO_KEYS.
+ int (*derive_secret)(struct ufs_hba *hba, const u8 *wrapped_key, + unsigned int wrapped_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]);
This probably should be called derive_sw_secret, not just derive_secret. - Eric