Add reading SATA encryption information

Functionality reads information about SATA disk encryption. Technical
documentation used is given in the implementation.

The implementation is able to recognized two encryption standards for SATA
drives, OPAL and ATA security.

If the SATA drive supports OPAL, encryption status and ability are
determined based on Opal Level 0 discovery response, for ATA security,
based on ATA identify response. If SATA supports OPAL, ability is set to
"SED", for ATA security to "Other".

SED(Self-Encrypting Drive) is commonly used to describe drive which using
OPAL or Enterprise standards developed by Trusted Computing Group. Ability
"Other" is used for ATA security because we rely only on information from
ATA identify which describe the overall state of encryption.

It is allowed to mix disks with different encryption ability such as "SED"
and "Other" and it is not security gap.

Motivation for adding this functionality is to block mixing of disks in
IMSM arrays with encryption enabled and disabled. The main goal is to not
allow stealing data by rebuilding array to not encrypted drive which can be
read elsewhere.

For SATA Opal drives, libata allow_tmp parameter enabled is required, which
is necessary for Opal Security commands to work, therefore, if the
parameter is not enabled, SATA Opal disk cannot be used in case the
encryption will be checked by metadata.

Implemented functions will be used in one of the next patches. In one of
the next patches, a flag will be added to enable disabling SATA Opal
encryption checking due to allow_tpm kernel setting dependency.

Signed-off-by: Blazej Kucman <blazej.kucman@intel.com>
Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>

1 files changed, 318 insertions, 0 deletions

diff --git a/drive_encryption.c b/drive_encryption.c
index b44585a7..d520f0c7 100644
--- a/drive_encryption.c
+++ b/drive_encryption.c
@@ -10,8 +10,12 @@
 
 #include <asm/types.h>
 #include <linux/nvme_ioctl.h>
+#include <scsi/sg.h>
+#include <scsi/scsi.h>
 #include "drive_encryption.h"
 
+#define DEFAULT_SECTOR_SIZE (512)
+
 /*
  * Opal defines
  * TCG Storage Opal SSC 2.01 chapter 3.3.3
@@ -34,6 +38,35 @@
 #define NVME_OACS_BYTE_POSITION (256)
 #define NVME_IDENTIFY_CONTROLLER_DATA (1)
 
+/*
+ * ATA defines
+ * ATA/ATAPI Command Set ATA8-ACS
+ * SCSI / ATA Translation - 3 (SAT-3)
+ * SCSI Primary Commands - 4 (SPC-4)
+ * AT Attachment-8 - ATA Serial Transport (ATA8-AST)
+ * ATA Command Pass-Through
+ */
+#define ATA_IDENTIFY (0xec)
+#define ATA_TRUSTED_RECEIVE (0x5c)
+#define ATA_SECURITY_WORD_POSITION (128)
+#define HDIO_DRIVE_CMD (0x031f)
+#define ATA_TRUSTED_COMPUTING_POS (48)
+#define ATA_PASS_THROUGH_12 (0xa1)
+#define ATA_IDENTIFY_RESPONSE_LEN (512)
+#define ATA_PIO_DATA_IN (4)
+#define SG_CHECK_CONDITION (0x02)
+#define ATA_STATUS_RETURN_DESCRIPTOR (0x09)
+#define ATA_PT_INFORMATION_AVAILABLE_ASCQ (0x1d)
+#define ATA_PT_INFORMATION_AVAILABLE_ASC (0x00)
+#define ATA_INQUIRY_LENGTH (0x0c)
+#define SG_INTERFACE_ID 'S'
+#define SG_IO_TIMEOUT (60000)
+#define SG_SENSE_SIZE (32)
+#define SENSE_DATA_CURRENT_FIXED (0x70)
+#define SENSE_DATA_CURRENT_DESC (0x72)
+#define SENSE_CURRENT_RES_DESC_POS (8)
+#define SG_DRIVER_SENSE	(0x08)
+
 typedef enum drive_feature_support_status {
 	/* Drive feature is supported. */
 	DRIVE_FEAT_SUP_ST = 0,
@@ -87,6 +120,27 @@ typedef struct supported_security_protocols {
 	__u8  list[504];
 } supported_security_protocols_t;
 
+/* ATA/ATAPI Command Set - 3 (ACS-3), Table 45 */
+typedef struct ata_security_status {
+	__u16 security_supported : 1;
+	__u16 security_enabled : 1;
+	__u16 security_locked : 1;
+	__u16 security_frozen : 1;
+	__u16 security_count_expired : 1;
+	__u16 enhanced_security_erase_supported : 1;
+	__u16 reserved1 : 2;
+	__u16 security_level : 1;
+	__u16 reserved2 : 7;
+} __attribute__((__packed__)) ata_security_status_t;
+
+/* ATA/ATAPI Command Set - 3 (ACS-3), Table 45 */
+typedef struct ata_trusted_computing {
+	__u16 tc_feature :1;
+	__u16 reserved : 13;
+	__u16 var1 : 1;
+	__u16 var2 : 1;
+} __attribute__((__packed__)) ata_trusted_computing_t;
+
 /**
  * get_opal_locking_feature_description() - get opal locking feature description.
  * @response: response from Opal Discovery Level 0.
@@ -360,3 +414,267 @@ get_nvme_opal_encryption_information(int disk_fd, encryption_information_t *info
 
 	return status;
 }
+
+/**
+ * ata_pass_through12_ioctl() - ata pass through12 ioctl.
+ * @disk_fd: a disk file descriptor.
+ * @ata_command: ata command.
+ * @sec_protocol: security protocol.
+ * @comm_id: additional command id.
+ * @response_buffer: response buffer to fill out.
+ * @buf_size: response buffer size.
+ * @verbose: verbose flag.
+ *
+ * Based on the documentations ATA Command Pass-Through, chapter 13.2.2 and
+ * ATA Translation - 3 (SAT-3), send read ata pass through 12 command via ioctl().
+ * On success, @response_buffer will be completed.
+ *
+ * Return: %MDADM_STATUS_SUCCESS on success, %MDADM_STATUS_ERROR on fail.
+ */
+static mdadm_status_t
+ata_pass_through12_ioctl(int disk_fd, __u8 ata_command,  __u8 sec_protocol, __u16 comm_id,
+			 void *response_buffer, size_t buf_size, const int verbose)
+{
+	__u8 cdb[ATA_INQUIRY_LENGTH] = {0};
+	__u8 sense[SG_SENSE_SIZE] = {0};
+	__u8 *sense_desc = NULL;
+	sg_io_hdr_t sg = {0};
+
+	/*
+	 * ATA Command Pass-Through, chapter 13.2.2
+	 * SCSI Primary Commands - 4 (SPC-4)
+	 * ATA Translation - 3 (SAT-3)
+	 */
+	cdb[0] = ATA_PASS_THROUGH_12;
+	/* protocol, bits 1-4 */
+	cdb[1] = ATA_PIO_DATA_IN << 1;
+	/* Bytes: CK_COND=1, T_DIR = 1, BYTE_BLOCK = 1, Length in Sector Count = 2 */
+	cdb[2] = 0x2E;
+	cdb[3] = sec_protocol;
+	/* Sector count */
+	cdb[4] = buf_size / DEFAULT_SECTOR_SIZE;
+	cdb[6] = (comm_id) & 0xFF;
+	cdb[7] = (comm_id >> 8) & 0xFF;
+	cdb[9] = ata_command;
+
+	sg.interface_id = SG_INTERFACE_ID;
+	sg.cmd_len = sizeof(cdb);
+	sg.mx_sb_len = sizeof(sense);
+	sg.dxfer_direction = SG_DXFER_FROM_DEV;
+	sg.dxfer_len = buf_size;
+	sg.dxferp = response_buffer;
+	sg.cmdp = cdb;
+	sg.sbp = sense;
+	sg.timeout = SG_IO_TIMEOUT;
+	sg.usr_ptr = NULL;
+
+	if (ioctl(disk_fd, SG_IO, &sg) < 0) {
+		pr_vrb("Failed ata passthrough12 ioctl. Device: /dev/%s.\n", fd2kname(disk_fd));
+		return MDADM_STATUS_ERROR;
+	}
+
+	if ((sg.status && sg.status != SG_CHECK_CONDITION) || sg.host_status ||
+	    (sg.driver_status && sg.driver_status != SG_DRIVER_SENSE)) {
+		pr_vrb("Failed ata passthrough12 ioctl. Device: /dev/%s.\n", fd2kname(disk_fd));
+		pr_vrb("SG_IO error: ATA_12 Status: %d Host Status: %d, Driver Status: %d\n",
+		       sg.status, sg.host_status, sg.driver_status);
+		return MDADM_STATUS_ERROR;
+	}
+
+	/* verify expected sense response code */
+	if (!(sense[0] == SENSE_DATA_CURRENT_DESC || sense[0] == SENSE_DATA_CURRENT_FIXED)) {
+		pr_vrb("Failed ata passthrough12 ioctl. Device: /dev/%s.\n", fd2kname(disk_fd));
+		return MDADM_STATUS_ERROR;
+	}
+
+	sense_desc = sense + SENSE_CURRENT_RES_DESC_POS;
+	/* verify sense data current response with descriptor format */
+	if (sense[0] == SENSE_DATA_CURRENT_DESC &&
+	    !(sense_desc[0] == ATA_STATUS_RETURN_DESCRIPTOR &&
+	    sense_desc[1] == ATA_INQUIRY_LENGTH)) {
+		pr_vrb("Failed ata passthrough12 ioctl. Device: /dev/%s. Sense data ASC: %d, ASCQ: %d.\n",
+		       fd2kname(disk_fd), sense[2], sense[3]);
+		return MDADM_STATUS_ERROR;
+	}
+
+	/* verify sense data current response with fixed format */
+	if (sense[0] == SENSE_DATA_CURRENT_FIXED &&
+	    !(sense[12] == ATA_PT_INFORMATION_AVAILABLE_ASC &&
+	    sense[13] == ATA_PT_INFORMATION_AVAILABLE_ASCQ)) {
+		pr_vrb("Failed ata passthrough12 ioctl. Device: /dev/%s. Sense data ASC: %d, ASCQ: %d.\n",
+		       fd2kname(disk_fd), sense[12], sense[13]);
+		return MDADM_STATUS_ERROR;
+	}
+
+	return MDADM_STATUS_SUCCESS;
+}
+
+/**
+ * is_sec_prot_01h_supported_ata() - check if security protocol 01h supported for given SATA disk.
+ * @disk_fd: a disk file descriptor.
+ * @verbose: verbose flag.
+ *
+ * Return: %DRIVE_FEAT_SUP_ST if TCG_SECP_01 supported, %DRIVE_FEAT_NOT_SUP_ST if not supported,
+ * %DRIVE_FEAT_CHECK_FAILED_ST if failed.
+ */
+static drive_feat_sup_st is_sec_prot_01h_supported_ata(int disk_fd, const int verbose)
+{
+	supported_security_protocols_t security_protocols;
+
+	mdadm_status_t result = ata_pass_through12_ioctl(disk_fd, ATA_TRUSTED_RECEIVE, TCG_SECP_00,
+							 0x0, &security_protocols,
+							 sizeof(security_protocols), verbose);
+	if (result)
+		return DRIVE_FEAT_CHECK_FAILED_ST;
+
+	if (is_sec_prot_01h_supported(&security_protocols))
+		return DRIVE_FEAT_SUP_ST;
+
+	return DRIVE_FEAT_NOT_SUP_ST;
+}
+
+/**
+ * is_ata_trusted_computing_supported() - check if ata trusted computing supported.
+ * @buffer: buffer with ATA identify response, not NULL.
+ *
+ * Return: true if trusted computing bit set, false otherwise.
+ */
+bool is_ata_trusted_computing_supported(__u16 *buffer)
+{
+	/* Added due to warnings from the compiler about a possible uninitialized variable below. */
+	assert(buffer);
+
+	__u16 security_tc_frame = __le16_to_cpu(buffer[ATA_TRUSTED_COMPUTING_POS]);
+	ata_trusted_computing_t *security_tc = (ata_trusted_computing_t *)&security_tc_frame;
+
+	if (security_tc->tc_feature == 1)
+		return true;
+
+	return false;
+}
+
+/**
+ * get_ata_standard_security_status() - get ATA disk encryption information from ATA identify.
+ * @buffer: buffer with response from ATA identify, not NULL.
+ * @information: struct to fill out, describing encryption status of disk.
+ *
+ * The function based on the Security status frame from ATA identify,
+ * completed encryption information.
+ * For possible encryption statuses and abilities,
+ * please refer to enums &encryption_status and &encryption_ability.
+ *
+ * Return: %MDADM_STATUS_SUCCESS on success, %MDADM_STATUS_ERROR on fail.
+ */
+static mdadm_status_t get_ata_standard_security_status(__u16 *buffer,
+						       struct encryption_information *information)
+{
+	/* Added due to warnings from the compiler about a possible uninitialized variable below. */
+	assert(buffer);
+
+	__u16 security_status_frame = __le16_to_cpu(buffer[ATA_SECURITY_WORD_POSITION]);
+	ata_security_status_t *security_status = (ata_security_status_t *)&security_status_frame;
+
+	if (!security_status->security_supported) {
+		information->ability = ENC_ABILITY_NONE;
+		information->status = ENC_STATUS_UNENCRYPTED;
+
+		return MDADM_STATUS_SUCCESS;
+	}
+
+	information->ability = ENC_ABILITY_OTHER;
+
+	if (security_status->security_enabled == 0)
+		information->status = ENC_STATUS_UNENCRYPTED;
+	else if (security_status->security_locked == 1)
+		information->status = ENC_STATUS_LOCKED;
+	else
+		information->status = ENC_STATUS_UNLOCKED;
+
+	return MDADM_STATUS_SUCCESS;
+}
+
+/**
+ * is_ata_opal() - check if SATA disk support Opal.
+ * @disk_fd: a disk file descriptor.
+ * @buffer: buffer with ATA identify response.
+ * @verbose: verbose flag.
+ *
+ * Return: %DRIVE_FEAT_SUP_ST if TCG_SECP_01 supported, %DRIVE_FEAT_NOT_SUP_ST if not supported,
+ * %DRIVE_FEAT_CHECK_FAILED_ST if failed to check.
+ */
+static drive_feat_sup_st is_ata_opal(int disk_fd, __u16 *buffer_identify, const int verbose)
+{
+	bool tc_status = is_ata_trusted_computing_supported(buffer_identify);
+	drive_feat_sup_st tcg_sec_prot_status;
+
+	if (!tc_status)
+		return DRIVE_FEAT_NOT_SUP_ST;
+
+	tcg_sec_prot_status = is_sec_prot_01h_supported_ata(disk_fd, verbose);
+
+	if (tcg_sec_prot_status == DRIVE_FEAT_CHECK_FAILED_ST) {
+		pr_vrb("Failed to verify if security protocol 01h supported. Device /dev/%s.\n",
+		       fd2kname(disk_fd));
+		return DRIVE_FEAT_CHECK_FAILED_ST;
+	}
+
+	if (tc_status && tcg_sec_prot_status == DRIVE_FEAT_SUP_ST)
+		return DRIVE_FEAT_SUP_ST;
+
+	return DRIVE_FEAT_NOT_SUP_ST;
+}
+
+/**
+ * get_ata_encryption_information() - get ATA disk encryption information.
+ * @disk_fd: a disk file descriptor.
+ * @information: struct to fill out, describing encryption status of disk.
+ * @verbose: verbose flag.
+ *
+ * The function reads information about encryption, if the disk supports Opal,
+ * the information is completed based on Opal Level 0 discovery, otherwise,
+ * based on ATA security status frame from ATA identification response.
+ * For possible encryption statuses and abilities,
+ * please refer to enums &encryption_status and &encryption_ability.
+ *
+ * Based on the documentations ATA/ATAPI Command Set ATA8-ACS and
+ * AT Attachment-8 - ATA Serial Transport (ATA8-AST).
+ *
+ * Return: %MDADM_STATUS_SUCCESS on success, %MDADM_STATUS_ERROR on fail.
+ */
+mdadm_status_t
+get_ata_encryption_information(int disk_fd, struct encryption_information *information,
+			       const int verbose)
+{
+	__u8 buffer_opal_level0_discovery[OPAL_IO_BUFFER_LEN] = {0};
+	__u16 buffer_identify[ATA_IDENTIFY_RESPONSE_LEN] = {0};
+	drive_feat_sup_st ata_opal_status;
+	mdadm_status_t status;
+
+	/* Get disk ATA identification */
+	status = ata_pass_through12_ioctl(disk_fd, ATA_IDENTIFY, 0x0, 0x0, buffer_identify,
+					  sizeof(buffer_identify), verbose);
+	if (status == MDADM_STATUS_ERROR)
+		return MDADM_STATUS_ERROR;
+
+	if (is_ata_trusted_computing_supported(buffer_identify) &&
+	    !sysfs_is_libata_allow_tpm_enabled(verbose)) {
+		pr_vrb("For SATA with Trusted Computing support, required libata.tpm_enabled=1.\n");
+		return MDADM_STATUS_ERROR;
+	}
+
+	ata_opal_status = is_ata_opal(disk_fd, buffer_identify, verbose);
+	if (ata_opal_status == DRIVE_FEAT_CHECK_FAILED_ST)
+		return MDADM_STATUS_ERROR;
+
+	if (ata_opal_status == DRIVE_FEAT_NOT_SUP_ST)
+		return get_ata_standard_security_status(buffer_identify, information);
+
+	/* SATA Opal */
+	status = ata_pass_through12_ioctl(disk_fd, ATA_TRUSTED_RECEIVE, TCG_SECP_01,
+					  OPAL_DISCOVERY_COMID, buffer_opal_level0_discovery,
+					  OPAL_IO_BUFFER_LEN, verbose);
+	if (status != MDADM_STATUS_SUCCESS)
+		return MDADM_STATUS_ERROR;
+
+	return get_opal_encryption_information(buffer_opal_level0_discovery, information);
+}