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scsi: ufs: rpmb: Use a fixed-length RPMB dev_id

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The RPMB authentication key is derived from the dev_id handed to the RPMB
subsystem. OP-TEE implements the eMMC RPMB flow, where the dev_id is the
eMMC CID: a fixed 16-byte value the key derivation depends on.

The UFS RPMB id is "<device_id>-R<region>", which is variable length and
longer than 16 bytes. Handing it to the RPMB subsystem as-is would tie the
derived key to a length OP-TEE does not expect and diverge from the
fixed-CID eMMC ABI, forcing OP-TEE to be taught about variable-length UFS
ids.

A fixed 16-byte dev_id is needed so the derived key stays stable and unique
per region while matching the eMMC CID layout OP-TEE relies on, keeping the
key-derivation ABI identical with no OP-TEE change. The reduction to a
fixed 16 bytes must also be reproducible by the bootloaders (such as
U-Boot) that derive the same dev_id.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Stanley Jhu <stanleyjhu@google.com>
Link: https://patch.msgid.link/20260831154804.719528-3-jorge.ramirez@oss.qualcomm.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>
This commit is contained in:
Jorge Ramirez-Ortiz 2026-08-31 17:48:01 +02:00 committed by Martin K. Petersen (Oracle)
parent a8a34238e5
commit 657eff806d
2 changed files with 8 additions and 2 deletions
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1
drivers/ufs/Kconfig
View File

@ -7,6 +7,7 @@ menuconfig SCSI_UFSHCD
tristate "Universal Flash Storage Controller"
depends on SCSI && SCSI_DMA
depends on RPMB || !RPMB
select CRYPTO_LIB_BLAKE2B if RPMB
select PM_DEVFREQ
select DEVFREQ_GOV_SIMPLE_ONDEMAND
select NLS

9
drivers/ufs/core/ufs-rpmb.c
View File

@ -10,6 +10,7 @@
* Can Guo <can.guo@oss.qualcomm.com>
*/
#include <crypto/blake2b.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
@ -21,6 +22,7 @@
#include <linux/unaligned.h>
#include "ufshcd-priv.h"
#define UFS_RPMB_ID_LEN 16 /* Match eMMC CID Length */
#define UFS_RPMB_UA_RETRIES 3 /* Retries for the power-on UNIT ATTENTION */
#define UFS_RPMB_SEC_PROTOCOL 0xEC /* JEDEC UFS application */
#define UFS_RPMB_SEC_PROTOCOL_ID 0x01 /* JEDEC UFS RPMB protocol ID, CDB byte3 */
@ -157,6 +159,7 @@ static void ufs_rpmb_device_release(struct device *dev)
int ufs_rpmb_probe(struct ufs_hba *hba)
{
struct ufs_rpmb_dev *ufs_rpmb, *it, *tmp;
u8 dev_id[UFS_RPMB_ID_LEN];
struct rpmb_dev *rdev;
char *cid = NULL;
int region;
@ -215,8 +218,10 @@ int ufs_rpmb_probe(struct ufs_hba *hba)
goto err_out;
}
descr.dev_id = cid;
descr.dev_id_len = strlen(cid);
blake2b(NULL, 0, cid, strlen(cid), dev_id, UFS_RPMB_ID_LEN);
descr.dev_id = dev_id;
descr.dev_id_len = UFS_RPMB_ID_LEN;
descr.capacity = cap;
/* Register RPMB device */