[PATCH v3 3/3] block: sed-opal: keyring support for SED keys
Hannes Reinecke
hare at suse.de
Wed Nov 30 18:00:43 AEDT 2022
On 11/30/22 00:25, gjoyce at linux.vnet.ibm.com wrote:
> From: Greg Joyce <gjoyce at linux.vnet.ibm.com>
>
> Extend the SED block driver so it can alternatively
> obtain a key from a sed-opal kernel keyring. The SED
> ioctls will indicate the source of the key, either
> directly in the ioctl data or from the keyring.
>
> This allows the use of SED commands in scripts such as
> udev scripts so that drives may be automatically unlocked
> as they become available.
>
> Signed-off-by: Greg Joyce <gjoyce at linux.vnet.ibm.com>
> Reviewed-by: Jonathan Derrick <jonathan.derrick at linux.dev>
> ---
> block/Kconfig | 1 +
> block/sed-opal.c | 174 +++++++++++++++++++++++++++++++++-
> include/linux/sed-opal.h | 3 +
> include/uapi/linux/sed-opal.h | 8 +-
> 4 files changed, 183 insertions(+), 3 deletions(-)
>
> diff --git a/block/Kconfig b/block/Kconfig
> index 444c5ab3b67e..b46f93ac8405 100644
> --- a/block/Kconfig
> +++ b/block/Kconfig
> @@ -181,6 +181,7 @@ config BLK_DEBUG_FS_ZONED
>
> config BLK_SED_OPAL
> bool "Logic for interfacing with Opal enabled SEDs"
> + depends on KEYS
> help
> Builds Logic for interfacing with Opal enabled controllers.
> Enabling this option enables users to setup/unlock/lock
> diff --git a/block/sed-opal.c b/block/sed-opal.c
> index 993b2b7cc4c2..a8729892178b 100644
> --- a/block/sed-opal.c
> +++ b/block/sed-opal.c
> @@ -20,6 +20,9 @@
> #include <linux/sed-opal.h>
> #include <linux/string.h>
> #include <linux/kdev_t.h>
> +#include <linux/key.h>
> +#include <linux/key-type.h>
> +#include <keys/user-type.h>
>
> #include "opal_proto.h"
>
> @@ -29,6 +32,8 @@
> /* Number of bytes needed by cmd_finalize. */
> #define CMD_FINALIZE_BYTES_NEEDED 7
>
> +static struct key *sed_opal_keyring;
> +
> struct opal_step {
> int (*fn)(struct opal_dev *dev, void *data);
> void *data;
> @@ -265,6 +270,101 @@ static void print_buffer(const u8 *ptr, u32 length)
> #endif
> }
>
> +/*
> + * Allocate/update a SED Opal key and add it to the SED Opal keyring.
> + */
> +static int update_sed_opal_key(const char *desc, u_char *key_data, int keylen)
> +{
> + key_ref_t kr;
> +
> + if (!sed_opal_keyring)
> + return -ENOKEY;
> +
> + kr = key_create_or_update(make_key_ref(sed_opal_keyring, true), "user",
> + desc, (const void *)key_data, keylen,
> + KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_WRITE,
> + KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN |
> + KEY_ALLOC_BYPASS_RESTRICTION);
> + if (IS_ERR(kr)) {
> + pr_err("Error adding SED key (%ld)\n", PTR_ERR(kr));
> + return PTR_ERR(kr);
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Read a SED Opal key from the SED Opal keyring.
> + */
> +static int read_sed_opal_key(const char *key_name, u_char *buffer, int buflen)
> +{
> + int ret;
> + key_ref_t kref;
> + struct key *key;
> +
> + if (!sed_opal_keyring)
> + return -ENOKEY;
> +
> + kref = keyring_search(make_key_ref(sed_opal_keyring, true),
> + &key_type_user, key_name, true);
> +
> + if (IS_ERR(kref))
> + ret = PTR_ERR(kref);
> +
> + key = key_ref_to_ptr(kref);
> + down_read(&key->sem);
> + ret = key_validate(key);
> + if (ret == 0) {
> + if (buflen > key->datalen)
> + buflen = key->datalen;
> +
> + ret = key->type->read(key, (char *)buffer, buflen);
> + }
> + up_read(&key->sem);
> +
> + key_ref_put(kref);
> +
> + return ret;
> +}
> +
> +static int opal_get_key(struct opal_dev *dev, struct opal_key *key)
> +{
> + int ret = 0;
> +
> + switch (key->key_type) {
> + case OPAL_INCLUDED:
> + /* the key is ready to use */
> + break;
> + case OPAL_KEYRING:
> + /* the key is in the keyring */
> + ret = read_sed_opal_key(OPAL_AUTH_KEY, key->key, OPAL_KEY_MAX);
> + if (ret > 0) {
> + if (ret > 255) {
Why is a key longer than 255 an error?
If this is a requirement, why not move the check into
read_sed_opal_key() such that one only has to check for
ret < 0 on errors?
> + ret = -ENOSPC;
> + goto error;
> + }
> + key->key_len = ret;
> + key->key_type = OPAL_INCLUDED;
> + }
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> + if (ret < 0)
> + goto error;
> +
> + /* must have a PEK by now or it's an error */
> + if (key->key_type != OPAL_INCLUDED || key->key_len == 0) {
> + ret = -EINVAL;
> + goto error;
> + }
> + return 0;
> +error:
> + pr_debug("Error getting password: %d\n", ret);
> + return ret;
> +}
> +
> static bool check_tper(const void *data)
> {
> const struct d0_tper_features *tper = data;
> @@ -2269,6 +2369,9 @@ static int opal_secure_erase_locking_range(struct opal_dev *dev,
> };
> int ret;
>
> + ret = opal_get_key(dev, &opal_session->opal_key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, erase_steps, ARRAY_SIZE(erase_steps));
> @@ -2302,6 +2405,9 @@ static int opal_revertlsp(struct opal_dev *dev, struct opal_revert_lsp *rev)
> };
> int ret;
>
> + ret = opal_get_key(dev, &rev->key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, steps, ARRAY_SIZE(steps));
> @@ -2320,6 +2426,9 @@ static int opal_erase_locking_range(struct opal_dev *dev,
> };
> int ret;
>
> + ret = opal_get_key(dev, &opal_session->opal_key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, erase_steps, ARRAY_SIZE(erase_steps));
> @@ -2348,6 +2457,9 @@ static int opal_enable_disable_shadow_mbr(struct opal_dev *dev,
> opal_mbr->enable_disable != OPAL_MBR_DISABLE)
> return -EINVAL;
>
> + ret = opal_get_key(dev, &opal_mbr->key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, mbr_steps, ARRAY_SIZE(mbr_steps));
> @@ -2373,6 +2485,9 @@ static int opal_set_mbr_done(struct opal_dev *dev,
> mbr_done->done_flag != OPAL_MBR_NOT_DONE)
> return -EINVAL;
>
> + ret = opal_get_key(dev, &mbr_done->key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, mbr_steps, ARRAY_SIZE(mbr_steps));
> @@ -2394,6 +2509,9 @@ static int opal_write_shadow_mbr(struct opal_dev *dev,
> if (info->size == 0)
> return 0;
>
> + ret = opal_get_key(dev, &info->key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, mbr_steps, ARRAY_SIZE(mbr_steps));
> @@ -2450,6 +2568,9 @@ static int opal_add_user_to_lr(struct opal_dev *dev,
> return -EINVAL;
> }
>
> + ret = opal_get_key(dev, &lk_unlk->session.opal_key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, steps, ARRAY_SIZE(steps));
> @@ -2472,6 +2593,10 @@ static int opal_reverttper(struct opal_dev *dev, struct opal_key *opal, bool psi
>
> int ret;
>
> + ret = opal_get_key(dev, opal);
> +
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> if (psid)
> @@ -2534,6 +2659,9 @@ static int opal_lock_unlock(struct opal_dev *dev,
> if (lk_unlk->session.who > OPAL_USER9)
> return -EINVAL;
>
> + ret = opal_get_key(dev, &lk_unlk->session.opal_key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> ret = __opal_lock_unlock(dev, lk_unlk);
> mutex_unlock(&dev->dev_lock);
> @@ -2556,6 +2684,9 @@ static int opal_take_ownership(struct opal_dev *dev, struct opal_key *opal)
> if (!dev)
> return -ENODEV;
>
> + ret = opal_get_key(dev, opal);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, owner_steps, ARRAY_SIZE(owner_steps));
> @@ -2578,6 +2709,9 @@ static int opal_activate_lsp(struct opal_dev *dev,
> if (!opal_lr_act->num_lrs || opal_lr_act->num_lrs > OPAL_MAX_LRS)
> return -EINVAL;
>
> + ret = opal_get_key(dev, &opal_lr_act->key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, active_steps, ARRAY_SIZE(active_steps));
> @@ -2596,6 +2730,9 @@ static int opal_setup_locking_range(struct opal_dev *dev,
> };
> int ret;
>
> + ret = opal_get_key(dev, &opal_lrs->session.opal_key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, lr_steps, ARRAY_SIZE(lr_steps));
> @@ -2622,6 +2759,14 @@ static int opal_set_new_pw(struct opal_dev *dev, struct opal_new_pw *opal_pw)
> ret = execute_steps(dev, pw_steps, ARRAY_SIZE(pw_steps));
> mutex_unlock(&dev->dev_lock);
>
> + if (ret)
> + return ret;
> +
> + /* update keyring with new password */
> + ret = update_sed_opal_key(OPAL_AUTH_KEY,
> + opal_pw->new_user_pw.opal_key.key,
> + opal_pw->new_user_pw.opal_key.key_len);
> +
> return ret;
> }
>
What about key revocation?
You only allow to set a new key, but what happens with the old ones?
> @@ -2642,6 +2787,9 @@ static int opal_activate_user(struct opal_dev *dev,
> return -EINVAL;
> }
>
> + ret = opal_get_key(dev, &opal_session->opal_key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
> ret = execute_steps(dev, act_steps, ARRAY_SIZE(act_steps));
> @@ -2728,6 +2876,9 @@ static int opal_generic_read_write_table(struct opal_dev *dev,
> {
> int ret, bit_set;
>
> + ret = opal_get_key(dev, &rw_tbl->key);
> + if (ret)
> + return ret;
> mutex_lock(&dev->dev_lock);
> setup_opal_dev(dev);
>
> @@ -2776,9 +2927,9 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
> if (!capable(CAP_SYS_ADMIN))
> return -EACCES;
> if (!dev)
> - return -ENOTSUPP;
> + return -EOPNOTSUPP;
> if (!(dev->flags & OPAL_FL_SUPPORTED))
> - return -ENOTSUPP;
> + return -EOPNOTSUPP;
>
> if (cmd & IOC_IN) {
> p = memdup_user(arg, _IOC_SIZE(cmd));
> @@ -2854,3 +3005,22 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
> return ret;
> }
> EXPORT_SYMBOL_GPL(sed_ioctl);
> +
> +static int __init sed_opal_init(void)
> +{
> + struct key *kr;
> +
> + kr = keyring_alloc(".sed_opal",
> + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
> + (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW |
> + KEY_USR_READ | KEY_USR_SEARCH | KEY_USR_WRITE,
> + KEY_ALLOC_NOT_IN_QUOTA,
> + NULL, NULL);
> + if (IS_ERR(kr))
> + return PTR_ERR(kr);
> +
> + sed_opal_keyring = kr;
> +
> + return 0;
> +}
> +late_initcall(sed_opal_init);
Shouldn't you free the keyring on exit?
> diff --git a/include/linux/sed-opal.h b/include/linux/sed-opal.h
> index 7131d7f0eec2..57d483506b4a 100644
> --- a/include/linux/sed-opal.h
> +++ b/include/linux/sed-opal.h
> @@ -24,6 +24,9 @@ bool opal_unlock_from_suspend(struct opal_dev *dev);
> struct opal_dev *init_opal_dev(void *data, sec_send_recv *send_recv);
> int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *ioctl_ptr);
>
> +#define OPAL_AUTH_KEY "opal-boot-pin"
> +#define OPAL_AUTH_KEY_PREV "opal-boot-pin-prev"
> +
> static inline bool is_sed_ioctl(unsigned int cmd)
> {
> switch (cmd) {
> diff --git a/include/uapi/linux/sed-opal.h b/include/uapi/linux/sed-opal.h
> index fccde168e90c..6b79cdcf9518 100644
> --- a/include/uapi/linux/sed-opal.h
> +++ b/include/uapi/linux/sed-opal.h
> @@ -44,10 +44,16 @@ enum opal_lock_state {
> OPAL_LK = 0x04, /* 0100 */
> };
>
> +enum opal_key_type {
> + OPAL_INCLUDED = 0, /* key[] is the key */
> + OPAL_KEYRING, /* key is in keyring */
> +};
> +
> struct opal_key {
> __u8 lr;
> __u8 key_len;
> - __u8 __align[6];
> + __u8 key_type;
> + __u8 __align[5];
> __u8 key[OPAL_KEY_MAX];
> };
>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare at suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman
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