block: sed-opal: keystore access for SED Opal keys

Allow for permanent SED authentication keys by
reading/writing to the SED Opal non-volatile keystore.

Signed-off-by: Greg Joyce <gjoyce@linux.vnet.ibm.com>
Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
Link: https://lore.kernel.org/r/20231004201957.1451669-3-gjoyce@linux.vnet.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Greg Joyce

block/sed-opal.c

@@ -18,6 +18,7 @@
 #include <linux/uaccess.h>
 #include <uapi/linux/sed-opal.h>
 #include <linux/sed-opal.h>
+#include <linux/sed-opal-key.h>
 #include <linux/string.h>
 #include <linux/kdev_t.h>
 #include <linux/key.h>
@@ -3019,7 +3020,13 @@ static int opal_set_new_pw(struct opal_dev *dev, struct opal_new_pw *opal_pw)
 	if (ret)
 		return ret;
 
-	/* update keyring with new password */
+	/* update keyring and key store with new password */
+	ret = sed_write_key(OPAL_AUTH_KEY,
+			    opal_pw->new_user_pw.opal_key.key,
+			    opal_pw->new_user_pw.opal_key.key_len);
+	if (ret != -EOPNOTSUPP)
+		pr_warn("error updating SED key: %d\n", ret);
+
 	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);
@@ -3292,6 +3299,8 @@ EXPORT_SYMBOL_GPL(sed_ioctl);
 static int __init sed_opal_init(void)
 {
 	struct key *kr;
+	char init_sed_key[OPAL_KEY_MAX];
+	int keylen = OPAL_KEY_MAX - 1;
 
 	kr = keyring_alloc(".sed_opal",
 			   GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
@@ -3304,6 +3313,11 @@ static int __init sed_opal_init(void)
 
 	sed_opal_keyring = kr;
 
-	return 0;
+	if (sed_read_key(OPAL_AUTH_KEY, init_sed_key, &keylen) < 0) {
+		memset(init_sed_key, '\0', sizeof(init_sed_key));
+		keylen = OPAL_KEY_MAX - 1;
+	}
+
+	return update_sed_opal_key(OPAL_AUTH_KEY, init_sed_key, keylen);
 }
 late_initcall(sed_opal_init);