diff options
Diffstat (limited to 'security/selinux/ss/sidtab.h')
| -rw-r--r-- | security/selinux/ss/sidtab.h | 117 |
1 files changed, 90 insertions, 27 deletions
diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h index bbd5c0d1f3bd..832c85c70d83 100644 --- a/security/selinux/ss/sidtab.h +++ b/security/selinux/ss/sidtab.h @@ -3,52 +3,58 @@ * 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> + * Original author: Stephen Smalley, <stephen.smalley.work@gmail.com> * 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_leaf { +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; }; -struct sidtab_node_inner; -struct sidtab_node_leaf; - union sidtab_entry_inner { struct sidtab_node_inner *ptr_inner; - struct sidtab_node_leaf *ptr_leaf; + 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 SIDTAB_NODE_ALLOC_SIZE PAGE_SIZE -#define size_to_shift(size) ((size) == 1 ? 1 : (const_ilog2((size) - 1) + 1)) +#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_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_leaf)) + (SIDTAB_NODE_ALLOC_SIZE / sizeof(struct sidtab_entry)) -#define SIDTAB_MAX_BITS 31 /* limited to INT_MAX due to atomic_t range */ -#define SIDTAB_MAX (((u32)1 << SIDTAB_MAX_BITS) - 1) +#define SIDTAB_MAX_BITS 32 +#define SIDTAB_MAX U32_MAX /* ensure enough tree levels for SIDTAB_MAX entries */ -#define SIDTAB_MAX_LEVEL \ +#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_leaf entries[SIDTAB_LEAF_ENTRIES]; + struct sidtab_entry entries[SIDTAB_LEAF_ENTRIES]; }; struct sidtab_node_inner { @@ -57,41 +63,98 @@ struct sidtab_node_inner { struct sidtab_isid_entry { int set; - struct context context; + struct sidtab_entry entry; }; struct sidtab_convert_params { - int (*func)(struct context *oldc, struct context *newc, void *args); - void *args; + struct convert_context_args *args; struct sidtab *target; }; -#define SIDTAB_RCACHE_SIZE 3 +#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]; - atomic_t count; + /* + * 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; - /* reverse lookup cache */ - atomic_t rcache[SIDTAB_RCACHE_SIZE]; +#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 context *sidtab_search(struct sidtab *s, u32 sid); -struct context *sidtab_search_force(struct sidtab *s, u32 sid); +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); -int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid); +void sidtab_cancel_convert(struct sidtab *s); -void sidtab_destroy(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); -#endif /* _SS_SIDTAB_H_ */ +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_ */ |