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-rw-r--r--security/selinux/ss/sidtab.h159
1 files changed, 159 insertions, 0 deletions
diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
new file mode 100644
index 000000000..9fce0d553
--- /dev/null
+++ b/security/selinux/ss/sidtab.h
@@ -0,0 +1,159 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * A security identifier table (sidtab) is a lookup table
+ * of security context structures indexed by SID value.
+ *
+ * Original author: Stephen Smalley, <sds@tycho.nsa.gov>
+ * Author: Ondrej Mosnacek, <omosnacek@gmail.com>
+ *
+ * Copyright (C) 2018 Red Hat, Inc.
+ */
+#ifndef _SS_SIDTAB_H_
+#define _SS_SIDTAB_H_
+
+#include <linux/spinlock_types.h>
+#include <linux/log2.h>
+#include <linux/hashtable.h>
+
+#include "context.h"
+
+struct sidtab_entry {
+ u32 sid;
+ u32 hash;
+ struct context context;
+#if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0
+ struct sidtab_str_cache __rcu *cache;
+#endif
+ struct hlist_node list;
+};
+
+union sidtab_entry_inner {
+ struct sidtab_node_inner *ptr_inner;
+ struct sidtab_node_leaf *ptr_leaf;
+};
+
+/* align node size to page boundary */
+#define SIDTAB_NODE_ALLOC_SHIFT PAGE_SHIFT
+#define SIDTAB_NODE_ALLOC_SIZE PAGE_SIZE
+
+#define size_to_shift(size) ((size) == 1 ? 1 : (const_ilog2((size) - 1) + 1))
+
+#define SIDTAB_INNER_SHIFT \
+ (SIDTAB_NODE_ALLOC_SHIFT - size_to_shift(sizeof(union sidtab_entry_inner)))
+#define SIDTAB_INNER_ENTRIES ((size_t)1 << SIDTAB_INNER_SHIFT)
+#define SIDTAB_LEAF_ENTRIES \
+ (SIDTAB_NODE_ALLOC_SIZE / sizeof(struct sidtab_entry))
+
+#define SIDTAB_MAX_BITS 32
+#define SIDTAB_MAX U32_MAX
+/* ensure enough tree levels for SIDTAB_MAX entries */
+#define SIDTAB_MAX_LEVEL \
+ DIV_ROUND_UP(SIDTAB_MAX_BITS - size_to_shift(SIDTAB_LEAF_ENTRIES), \
+ SIDTAB_INNER_SHIFT)
+
+struct sidtab_node_leaf {
+ struct sidtab_entry entries[SIDTAB_LEAF_ENTRIES];
+};
+
+struct sidtab_node_inner {
+ union sidtab_entry_inner entries[SIDTAB_INNER_ENTRIES];
+};
+
+struct sidtab_isid_entry {
+ int set;
+ struct sidtab_entry entry;
+};
+
+struct sidtab_convert_params {
+ int (*func)(struct context *oldc, struct context *newc, void *args, gfp_t gfp_flags);
+ void *args;
+ struct sidtab *target;
+};
+
+#define SIDTAB_HASH_BITS CONFIG_SECURITY_SELINUX_SIDTAB_HASH_BITS
+#define SIDTAB_HASH_BUCKETS (1 << SIDTAB_HASH_BITS)
+
+struct sidtab {
+ /*
+ * lock-free read access only for as many items as a prior read of
+ * 'count'
+ */
+ union sidtab_entry_inner roots[SIDTAB_MAX_LEVEL + 1];
+ /*
+ * access atomically via {READ|WRITE}_ONCE(); only increment under
+ * spinlock
+ */
+ u32 count;
+ /* access only under spinlock */
+ struct sidtab_convert_params *convert;
+ bool frozen;
+ spinlock_t lock;
+
+#if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0
+ /* SID -> context string cache */
+ u32 cache_free_slots;
+ struct list_head cache_lru_list;
+ spinlock_t cache_lock;
+#endif
+
+ /* index == SID - 1 (no entry for SECSID_NULL) */
+ struct sidtab_isid_entry isids[SECINITSID_NUM];
+
+ /* Hash table for fast reverse context-to-sid lookups. */
+ DECLARE_HASHTABLE(context_to_sid, SIDTAB_HASH_BITS);
+};
+
+int sidtab_init(struct sidtab *s);
+int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context);
+struct sidtab_entry *sidtab_search_entry(struct sidtab *s, u32 sid);
+struct sidtab_entry *sidtab_search_entry_force(struct sidtab *s, u32 sid);
+
+static inline struct context *sidtab_search(struct sidtab *s, u32 sid)
+{
+ struct sidtab_entry *entry = sidtab_search_entry(s, sid);
+
+ return entry ? &entry->context : NULL;
+}
+
+static inline struct context *sidtab_search_force(struct sidtab *s, u32 sid)
+{
+ struct sidtab_entry *entry = sidtab_search_entry_force(s, sid);
+
+ return entry ? &entry->context : NULL;
+}
+
+int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params);
+
+void sidtab_cancel_convert(struct sidtab *s);
+
+void sidtab_freeze_begin(struct sidtab *s, unsigned long *flags) __acquires(&s->lock);
+void sidtab_freeze_end(struct sidtab *s, unsigned long *flags) __releases(&s->lock);
+
+int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid);
+
+void sidtab_destroy(struct sidtab *s);
+
+int sidtab_hash_stats(struct sidtab *sidtab, char *page);
+
+#if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0
+void sidtab_sid2str_put(struct sidtab *s, struct sidtab_entry *entry,
+ const char *str, u32 str_len);
+int sidtab_sid2str_get(struct sidtab *s, struct sidtab_entry *entry,
+ char **out, u32 *out_len);
+#else
+static inline void sidtab_sid2str_put(struct sidtab *s,
+ struct sidtab_entry *entry,
+ const char *str, u32 str_len)
+{
+}
+static inline int sidtab_sid2str_get(struct sidtab *s,
+ struct sidtab_entry *entry,
+ char **out, u32 *out_len)
+{
+ return -ENOENT;
+}
+#endif /* CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0 */
+
+#endif /* _SS_SIDTAB_H_ */
+
+