[v3,3/5] libstb/secvar: add secvar api implementation
diff mbox series

Message ID 20190903213416.16535-4-erichte@linux.ibm.com
State New
Headers show
Series
  • Add Secure Variable Support
Related show

Checks

Context Check Description
snowpatch_ozlabs/snowpatch_job_snowpatch-skiboot-dco success Signed-off-by present
snowpatch_ozlabs/snowpatch_job_snowpatch-skiboot success Test snowpatch/job/snowpatch-skiboot on branch master
snowpatch_ozlabs/apply_patch success Successfully applied on branch master (7b12d5489fcfd73ef7ec0cb27eff7f8a5f13b238)

Commit Message

Eric Richter Sept. 3, 2019, 9:34 p.m. UTC
This patch provides the OPAL runtime service frontend for the host OS to
retrieve secure variables, and append new ones for processing on the
next reboot. These calls operate on the internal abstraction or utilize
the platform-provided driver hooks, and therefore this API should not
need to be updated to support changes in storage or backend drivers.

Included are the following functions:
 - opal_secvar_get()
 - opal_secvar_get_next()
 - opal_secvar_enqueue_update()

opal_secvar_get() retrieves the data blob associated with a given key.
The data buffer may be set to NULL to only query for variable size. This
runtime service only operates on the variable bank.

opal_secvar_get_next() can be used to iterate through the list of
variable keys in the variable bank. Supplying an empty key (or zero key
length) returns the key of the first variable in the variable bank.
Supplying a valid key returns the key of the next variable in sequence.

opal_secvar_enqueue_update() provides a method for the host OS to submit
a new variable for processing on next boot, by appending it to the
update bank. As this does not affect the variable bank, appending a
variable via this runtime service will not affect the output of the
previous set of functions. The update queue is only processed during
secvar initialization.

V2:
 - removed opal_secvar_backend, replaced by DT node
 - removed unnecessary argument casting
 - all calls return OPAL_RESOURCE if secvar failed to init

V3:
 - remove metadata from API parameters
 - remove opal_secvar_get_size
 - change enqueue to replace an update with a repeat name, rather
    than enqueueing the duplicate
 - change enqueue to unstage an update matching a key if size is zero
 - make all key parameters const where possible
 - rename key_size to key_buf_size in _get_next
 - fix leaking node when enqueue could not allocate the secvar

Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
 ccan/list/list.h           |  38 +++++++++
 include/opal-api.h         |   5 +-
 libstb/secvar/Makefile.inc |   2 +-
 libstb/secvar/secvar_api.c | 158 +++++++++++++++++++++++++++++++++++++
 4 files changed, 201 insertions(+), 2 deletions(-)
 create mode 100644 libstb/secvar/secvar_api.c

Patch
diff mbox series

diff --git a/ccan/list/list.h b/ccan/list/list.h
index 7cd3a83e..fdeddeb4 100644
--- a/ccan/list/list.h
+++ b/ccan/list/list.h
@@ -523,4 +523,42 @@  static inline struct list_node *list_node_from_off_(void *ptr, size_t off)
 	(container_off_var(var, member) +		\
 	 check_type(var->member, struct list_node))
 
+
+#if HAVE_TYPEOF
+#define list_typeof(var) typeof(var)
+#else
+#define list_typeof(var) void *
+#endif
+
+
+/* Returns member, or NULL if at end of list. */
+static inline void *list_entry_or_null(const struct list_head *h,
+                                      const struct list_node *n,
+                                      size_t off)
+{
+       if (n == &h->n)
+               return NULL;
+       return (char *)n - off;
+}
+
+/**
+ * list_next - get the next entry in a list
+ * @h: the list_head
+ * @i: a pointer to an entry in the list.
+ * @member: the list_node member of the structure
+ *
+ * If @i was the last entry in the list, returns NULL.
+ *
+ * Example:
+ *     struct child *second;
+ *     second = list_next(&parent->children, first, list);
+ *     if (!second)
+ *             printf("No second child!\n");
+ */
+#define list_next(h, i, member)                                                \
+       ((list_typeof(i))list_entry_or_null(list_debug(h),              \
+                                           (i)->member.next,           \
+                                           list_off_var_((i), member)))
+
+
 #endif /* CCAN_LIST_H */
diff --git a/include/opal-api.h b/include/opal-api.h
index ee66bbbb..a7746789 100644
--- a/include/opal-api.h
+++ b/include/opal-api.h
@@ -222,7 +222,10 @@ 
 #define OPAL_MPIPL_UPDATE			173
 #define OPAL_MPIPL_REGISTER_TAG			174
 #define OPAL_MPIPL_QUERY_TAG			175
-#define OPAL_LAST				175
+#define OPAL_SECVAR_GET				176
+#define OPAL_SECVAR_GET_NEXT			177
+#define OPAL_SECVAR_ENQUEUE_UPDATE		178
+#define OPAL_LAST				178
 
 #define QUIESCE_HOLD			1 /* Spin all calls at entry */
 #define QUIESCE_REJECT			2 /* Fail all calls with OPAL_BUSY */
diff --git a/libstb/secvar/Makefile.inc b/libstb/secvar/Makefile.inc
index 75870910..50316b48 100644
--- a/libstb/secvar/Makefile.inc
+++ b/libstb/secvar/Makefile.inc
@@ -7,7 +7,7 @@  SUBDIRS += $(SECVAR_DIR)
 include $(SECVAR_DIR)/storage/Makefile.inc
 include $(SECVAR_DIR)/backend/Makefile.inc
 
-SECVAR_SRCS = secvar_main.c secvar_util.c
+SECVAR_SRCS = secvar_main.c secvar_util.c secvar_api.c
 SECVAR_OBJS = $(SECVAR_SRCS:%.c=%.o)
 SECVAR = $(SECVAR_DIR)/built-in.a
 
diff --git a/libstb/secvar/secvar_api.c b/libstb/secvar/secvar_api.c
new file mode 100644
index 00000000..3483837a
--- /dev/null
+++ b/libstb/secvar/secvar_api.c
@@ -0,0 +1,158 @@ 
+// SPDX-License-Identifier: Apache-2.0
+/* Copyright 2019 IBM Corp. */
+
+#ifndef pr_fmt
+#define pr_fmt(fmt) "SECVAR_API: " fmt
+#endif
+
+#include <opal.h>
+#include "secvar.h"
+
+
+static int64_t opal_secvar_get(const char *key, uint64_t key_len, void *data, uint64_t *data_size)
+{
+	struct secvar_node *node;
+	int64_t rc = OPAL_SUCCESS;
+
+	if (!secvar_enabled)
+		return OPAL_UNSUPPORTED;
+	if (!secvar_ready)
+		return OPAL_RESOURCE;
+	if (!key)
+		return OPAL_PARAMETER;
+	if (key_len == 0)
+		return OPAL_PARAMETER;
+	// Data size must be set, data is optional for size query
+	if (!data_size)
+		return OPAL_PARAMETER;
+
+	node = find_secvar(key, key_len, &variable_bank);
+
+	if (!node)
+		return OPAL_EMPTY; // Variable not found, bail early
+
+	if (!data)
+		rc = OPAL_SUCCESS;
+	else if (*data_size < node->var->data_size)
+		rc = OPAL_PARTIAL;
+	else
+		memcpy(data, node->var->data, node->var->data_size);
+
+	*data_size = node->var->data_size;
+
+	return rc;
+}
+opal_call(OPAL_SECVAR_GET, opal_secvar_get, 4);
+
+
+static int64_t opal_secvar_get_next(char *key, uint64_t *key_len, uint64_t key_buf_size)
+{
+	struct secvar_node *node;
+
+	if (!secvar_enabled)
+		return OPAL_UNSUPPORTED;
+	if (!secvar_ready)
+		return OPAL_RESOURCE;
+	if (!key_len)
+		return OPAL_PARAMETER;
+	if (key_buf_size == 0)
+		return OPAL_PARAMETER;
+	if (*key_len > SECVAR_MAX_KEY_LEN)
+		return OPAL_PARAMETER;
+	if (*key_len > key_buf_size)
+		return OPAL_PARAMETER;
+	if (!key)
+		return OPAL_PARAMETER;
+
+	if (!is_key_empty(key, *key_len)) {
+		node = find_secvar(key, *key_len, &variable_bank);
+		if (!node)
+			return OPAL_PARAMETER;
+
+		node = list_next(&variable_bank, node, link);
+	} else
+		node = list_top(&variable_bank, struct secvar_node, link);
+
+	if (!node)
+		return OPAL_EMPTY;
+
+	if (key_buf_size < node->var->key_len) {
+		*key_len = node->var->key_len;
+		return OPAL_PARTIAL;
+	}
+
+	*key_len = node->var->key_len;
+	memcpy(key, node->var->key, node->var->key_len);
+
+	return OPAL_SUCCESS;
+}
+opal_call(OPAL_SECVAR_GET_NEXT, opal_secvar_get_next, 3);
+
+
+static int64_t opal_secvar_enqueue_update(const char *key, uint64_t key_len, void *data, uint64_t data_size)
+{
+	struct secvar_node *node;
+
+	if (!secvar_enabled)
+		return OPAL_UNSUPPORTED;
+	if (!secvar_ready)
+		return OPAL_RESOURCE;
+	if (!secvar_storage.write_bank)
+		return OPAL_HARDWARE;
+	if (!key)
+		return OPAL_PARAMETER;
+	if (key_len == 0)
+		return OPAL_PARAMETER;
+	if (key_len > SECVAR_MAX_KEY_LEN)
+		return OPAL_PARAMETER;
+	if ((!data) && (data_size != 0))
+		return OPAL_PARAMETER;
+	if (data_size > SECVAR_MAX_DATA_SIZE)
+		return OPAL_PARAMETER;
+
+	// Key should not be empty
+	if (is_key_empty(key, key_len))
+		return OPAL_PARAMETER;
+
+	node = find_secvar(key, key_len, &update_bank);
+
+	// Unstage an update
+	if (data_size == 0) {
+		if (!node)
+			return OPAL_EMPTY;
+
+		if (node->var)
+			free(node->var);
+		list_del(&node->link);
+		free(node);
+		goto out;
+	}
+
+	if (node) {
+		list_del(&node->link);
+		memset(node->var, 0x00, sizeof(struct secvar) + node->var->data_size);
+	} else {
+		node = zalloc(sizeof(struct secvar_node));
+		if (!node)
+			return OPAL_NO_MEM;
+		node->var = zalloc(sizeof(struct secvar) + data_size);
+	}
+
+	if (!node->var) {
+		free(node);
+		return OPAL_NO_MEM;
+	}
+
+	memcpy(node->var->key, key, key_len);
+	node->var->key_len = key_len;
+	memcpy(node->var->data, data, data_size);
+	node->var->data_size = data_size;
+
+	list_add_tail(&update_bank, &node->link);
+
+out:
+	secvar_storage.write_bank(&update_bank, SECVAR_UPDATE_BANK);
+
+	return OPAL_SUCCESS;
+}
+opal_call(OPAL_SECVAR_ENQUEUE_UPDATE, opal_secvar_enqueue_update, 4);