diff options
| -rw-r--r-- | security/selinux/Kconfig | 12 | ||||
| -rw-r--r-- | security/selinux/include/security.h | 1 | ||||
| -rw-r--r-- | security/selinux/selinuxfs.c | 65 | ||||
| -rw-r--r-- | security/selinux/ss/context.h | 11 | ||||
| -rw-r--r-- | security/selinux/ss/policydb.c | 5 | ||||
| -rw-r--r-- | security/selinux/ss/services.c | 96 | ||||
| -rw-r--r-- | security/selinux/ss/services.h | 4 | ||||
| -rw-r--r-- | security/selinux/ss/sidtab.c | 263 | ||||
| -rw-r--r-- | security/selinux/ss/sidtab.h | 16 |
9 files changed, 306 insertions, 167 deletions
diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig index 5711689deb6a..c9e576c430c2 100644 --- a/security/selinux/Kconfig +++ b/security/selinux/Kconfig @@ -85,3 +85,15 @@ config SECURITY_SELINUX_CHECKREQPROT_VALUE via /selinux/checkreqprot if authorized by policy. If you are unsure how to answer this question, answer 0. + +config SECURITY_SELINUX_SIDTAB_HASH_BITS + int "NSA SELinux sidtab hashtable size" + depends on SECURITY_SELINUX + range 8 13 + default 9 + help + This option sets the number of buckets used in the sidtab hashtable + to 2^SECURITY_SELINUX_SIDTAB_HASH_BITS buckets. The number of hash + collisions may be viewed at /sys/fs/selinux/ss/sidtab_hash_stats. If + chain lengths are high (e.g. > 20) then selecting a higher value here + will ensure that lookups times are short and stable. diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index ae840634e3c7..8c0dbbd076c6 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -395,5 +395,6 @@ extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm); extern void avtab_cache_init(void); extern void ebitmap_cache_init(void); extern void hashtab_cache_init(void); +extern int security_sidtab_hash_stats(struct selinux_state *state, char *page); #endif /* _SELINUX_SECURITY_H_ */ diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index ee94fa469c29..dd7bb1f1dc99 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -1482,6 +1482,32 @@ static ssize_t sel_read_avc_hash_stats(struct file *filp, char __user *buf, return length; } +static ssize_t sel_read_sidtab_hash_stats(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct selinux_fs_info *fsi = file_inode(filp)->i_sb->s_fs_info; + struct selinux_state *state = fsi->state; + char *page; + ssize_t length; + + page = (char *)__get_free_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + length = security_sidtab_hash_stats(state, page); + if (length >= 0) + length = simple_read_from_buffer(buf, count, ppos, page, + length); + free_page((unsigned long)page); + + return length; +} + +static const struct file_operations sel_sidtab_hash_stats_ops = { + .read = sel_read_sidtab_hash_stats, + .llseek = generic_file_llseek, +}; + static const struct file_operations sel_avc_cache_threshold_ops = { .read = sel_read_avc_cache_threshold, .write = sel_write_avc_cache_threshold, @@ -1599,6 +1625,37 @@ static int sel_make_avc_files(struct dentry *dir) return 0; } +static int sel_make_ss_files(struct dentry *dir) +{ + struct super_block *sb = dir->d_sb; + struct selinux_fs_info *fsi = sb->s_fs_info; + int i; + static struct tree_descr files[] = { + { "sidtab_hash_stats", &sel_sidtab_hash_stats_ops, S_IRUGO }, + }; + + for (i = 0; i < ARRAY_SIZE(files); i++) { + struct inode *inode; + struct dentry *dentry; + + dentry = d_alloc_name(dir, files[i].name); + if (!dentry) + return -ENOMEM; + + inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode); + if (!inode) { + dput(dentry); + return -ENOMEM; + } + + inode->i_fop = files[i].ops; + inode->i_ino = ++fsi->last_ino; + d_add(dentry, inode); + } + + return 0; +} + static ssize_t sel_read_initcon(struct file *file, char __user *buf, size_t count, loff_t *ppos) { @@ -1963,6 +2020,14 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc) } ret = sel_make_avc_files(dentry); + + dentry = sel_make_dir(sb->s_root, "ss", &fsi->last_ino); + if (IS_ERR(dentry)) { + ret = PTR_ERR(dentry); + goto err; + } + + ret = sel_make_ss_files(dentry); if (ret) goto err; diff --git a/security/selinux/ss/context.h b/security/selinux/ss/context.h index 513e67f48878..3ba044fe02ed 100644 --- a/security/selinux/ss/context.h +++ b/security/selinux/ss/context.h @@ -31,6 +31,7 @@ struct context { u32 len; /* length of string in bytes */ struct mls_range range; char *str; /* string representation if context cannot be mapped. */ + u32 hash; /* a hash of the string representation */ }; static inline void mls_context_init(struct context *c) @@ -168,12 +169,13 @@ static inline int context_cpy(struct context *dst, struct context *src) kfree(dst->str); return rc; } + dst->hash = src->hash; return 0; } static inline void context_destroy(struct context *c) { - c->user = c->role = c->type = 0; + c->user = c->role = c->type = c->hash = 0; kfree(c->str); c->str = NULL; c->len = 0; @@ -182,6 +184,8 @@ static inline void context_destroy(struct context *c) static inline int context_cmp(struct context *c1, struct context *c2) { + if (c1->hash && c2->hash && (c1->hash != c2->hash)) + return 0; if (c1->len && c2->len) return (c1->len == c2->len && !strcmp(c1->str, c2->str)); if (c1->len || c2->len) @@ -192,5 +196,10 @@ static inline int context_cmp(struct context *c1, struct context *c2) mls_context_cmp(c1, c2)); } +static inline unsigned int context_compute_hash(const char *s) +{ + return full_name_hash(NULL, s, strlen(s)); +} + #endif /* _SS_CONTEXT_H_ */ diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index e20624a68f5d..e369b0092cdf 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -878,6 +878,11 @@ int policydb_load_isids(struct policydb *p, struct sidtab *s) sidtab_destroy(s); goto out; } + rc = context_add_hash(p, &c->context[0]); + if (rc) { + sidtab_destroy(s); + goto out; + } rc = sidtab_set_initial(s, c->sid[0], &c->context[0]); if (rc) { diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index a5813c7629c1..38fb6fdd65ca 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -1257,6 +1257,17 @@ static int context_struct_to_string(struct policydb *p, #include "initial_sid_to_string.h" +int security_sidtab_hash_stats(struct selinux_state *state, char *page) +{ + int rc; + + read_lock(&state->ss->policy_rwlock); + rc = sidtab_hash_stats(state->ss->sidtab, page); + read_unlock(&state->ss->policy_rwlock); + + return rc; +} + const char *security_get_initial_sid_context(u32 sid) { if (unlikely(sid > SECINITSID_NUM)) @@ -1449,6 +1460,42 @@ out: return rc; } +int context_add_hash(struct policydb *policydb, + struct context *context) +{ + int rc; + char *str; + int len; + + if (context->str) { + context->hash = context_compute_hash(context->str); + } else { + rc = context_struct_to_string(policydb, context, + &str, &len); + if (rc) + return rc; + context->hash = context_compute_hash(str); + kfree(str); + } + return 0; +} + +static int context_struct_to_sid(struct selinux_state *state, + struct context *context, u32 *sid) +{ + int rc; + struct sidtab *sidtab = state->ss->sidtab; + struct policydb *policydb = &state->ss->policydb; + + if (!context->hash) { + rc = context_add_hash(policydb, context); + if (rc) + return rc; + } + + return sidtab_context_to_sid(sidtab, context, sid); +} + static int security_context_to_sid_core(struct selinux_state *state, const char *scontext, u32 scontext_len, u32 *sid, u32 def_sid, gfp_t gfp_flags, @@ -1501,7 +1548,7 @@ static int security_context_to_sid_core(struct selinux_state *state, str = NULL; } else if (rc) goto out_unlock; - rc = sidtab_context_to_sid(sidtab, &context, sid); + rc = context_struct_to_sid(state, &context, sid); context_destroy(&context); out_unlock: read_unlock(&state->ss->policy_rwlock); @@ -1805,7 +1852,7 @@ static int security_compute_sid(struct selinux_state *state, goto out_unlock; } /* Obtain the sid for the context. */ - rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid); + rc = context_struct_to_sid(state, &newcontext, out_sid); out_unlock: read_unlock(&state->ss->policy_rwlock); context_destroy(&newcontext); @@ -1957,6 +2004,7 @@ static int convert_context(struct context *oldc, struct context *newc, void *p) context_init(newc); newc->str = s; newc->len = oldc->len; + newc->hash = oldc->hash; return 0; } kfree(s); @@ -2033,6 +2081,10 @@ static int convert_context(struct context *oldc, struct context *newc, void *p) goto bad; } + rc = context_add_hash(args->newp, newc); + if (rc) + goto bad; + return 0; bad: /* Map old representation to string and save it. */ @@ -2042,6 +2094,7 @@ bad: context_destroy(newc); newc->str = s; newc->len = len; + newc->hash = context_compute_hash(s); pr_info("SELinux: Context %s became invalid (unmapped).\n", newc->str); return 0; @@ -2280,8 +2333,7 @@ int security_port_sid(struct selinux_state *state, if (c) { if (!c->sid[0]) { - rc = sidtab_context_to_sid(sidtab, - &c->context[0], + rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]); if (rc) goto out; @@ -2306,14 +2358,12 @@ int security_ib_pkey_sid(struct selinux_state *state, u64 subnet_prefix, u16 pkey_num, u32 *out_sid) { struct policydb *policydb; - struct sidtab *sidtab; struct ocontext *c; int rc = 0; read_lock(&state->ss->policy_rwlock); policydb = &state->ss->policydb; - sidtab = state->ss->sidtab; c = policydb->ocontexts[OCON_IBPKEY]; while (c) { @@ -2327,7 +2377,7 @@ int security_ib_pkey_sid(struct selinux_state *state, if (c) { if (!c->sid[0]) { - rc = sidtab_context_to_sid(sidtab, + rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]); if (rc) @@ -2374,8 +2424,7 @@ int security_ib_endport_sid(struct selinux_state *state, if (c) { if (!c->sid[0]) { - rc = sidtab_context_to_sid(sidtab, - &c->context[0], + rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]); if (rc) goto out; @@ -2416,13 +2465,11 @@ int security_netif_sid(struct selinux_state *state, if (c) { if (!c->sid[0] || !c->sid[1]) { - rc = sidtab_context_to_sid(sidtab, - &c->context[0], - &c->sid[0]); + rc = context_struct_to_sid(state, &c->context[0], + &c->sid[0]); if (rc) goto out; - rc = sidtab_context_to_sid(sidtab, - &c->context[1], + rc = context_struct_to_sid(state, &c->context[1], &c->sid[1]); if (rc) goto out; @@ -2463,14 +2510,12 @@ int security_node_sid(struct selinux_state *state, u32 *out_sid) { struct policydb *policydb; - struct sidtab *sidtab; int rc; struct ocontext *c; read_lock(&state->ss->policy_rwlock); policydb = &state->ss->policydb; - sidtab = state->ss->sidtab; switch (domain) { case AF_INET: { @@ -2512,7 +2557,7 @@ int security_node_sid(struct selinux_state *state, if (c) { if (!c->sid[0]) { - rc = sidtab_context_to_sid(sidtab, + rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]); if (rc) @@ -2596,12 +2641,17 @@ int security_get_user_sids(struct selinux_state *state, usercon.role = i + 1; ebitmap_for_each_positive_bit(&role->types, tnode, j) { usercon.type = j + 1; + /* + * The same context struct is reused here so the hash + * must be reset. + */ + usercon.hash = 0; if (mls_setup_user_range(policydb, fromcon, user, &usercon)) continue; - rc = sidtab_context_to_sid(sidtab, &usercon, &sid); + rc = context_struct_to_sid(state, &usercon, &sid); if (rc) goto out_unlock; if (mynel < maxnel) { @@ -2672,7 +2722,6 @@ static inline int __security_genfs_sid(struct selinux_state *state, u32 *sid) { struct policydb *policydb = &state->ss->policydb; - struct sidtab *sidtab = state->ss->sidtab; int len; u16 sclass; struct genfs *genfs; @@ -2707,7 +2756,7 @@ static inline int __security_genfs_sid(struct selinux_state *state, goto out; if (!c->sid[0]) { - rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]); if (rc) goto out; } @@ -2770,7 +2819,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb) if (c) { sbsec->behavior = c->v.behavior; if (!c->sid[0]) { - rc = sidtab_context_to_sid(sidtab, &c->context[0], + rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]); if (rc) goto out; @@ -3026,8 +3075,7 @@ int security_sid_mls_copy(struct selinux_state *state, goto out_unlock; } } - - rc = sidtab_context_to_sid(sidtab, &newcon, new_sid); + rc = context_struct_to_sid(state, &newcon, new_sid); out_unlock: read_unlock(&state->ss->policy_rwlock); context_destroy(&newcon); @@ -3620,7 +3668,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state, if (!mls_context_isvalid(policydb, &ctx_new)) goto out_free; - rc = sidtab_context_to_sid(sidtab, &ctx_new, sid); + rc = context_struct_to_sid(state, &ctx_new, sid); if (rc) goto out_free; diff --git a/security/selinux/ss/services.h b/security/selinux/ss/services.h index 9a36de860368..fc40640a9725 100644 --- a/security/selinux/ss/services.h +++ b/security/selinux/ss/services.h @@ -8,7 +8,7 @@ #define _SS_SERVICES_H_ #include "policydb.h" -#include "sidtab.h" +#include "context.h" /* Mapping for a single class */ struct selinux_mapping { @@ -39,4 +39,6 @@ void services_compute_xperms_drivers(struct extended_perms *xperms, void services_compute_xperms_decision(struct extended_perms_decision *xpermd, struct avtab_node *node); +int context_add_hash(struct policydb *policydb, struct context *context); + #endif /* _SS_SERVICES_H_ */ diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c index 7d49994e8d5f..d9d8599e8e63 100644 --- a/security/selinux/ss/sidtab.c +++ b/security/selinux/ss/sidtab.c @@ -17,26 +17,43 @@ #include "security.h" #include "sidtab.h" +#define index_to_sid(index) (index + SECINITSID_NUM + 1) +#define sid_to_index(sid) (sid - (SECINITSID_NUM + 1)) + int sidtab_init(struct sidtab *s) { u32 i; memset(s->roots, 0, sizeof(s->roots)); - /* max count is SIDTAB_MAX so valid index is always < SIDTAB_MAX */ - for (i = 0; i < SIDTAB_RCACHE_SIZE; i++) - s->rcache[i] = SIDTAB_MAX; - for (i = 0; i < SECINITSID_NUM; i++) s->isids[i].set = 0; s->count = 0; s->convert = NULL; + hash_init(s->context_to_sid); spin_lock_init(&s->lock); return 0; } +static u32 context_to_sid(struct sidtab *s, struct context *context) +{ + struct sidtab_entry_leaf *entry; + u32 sid = 0; + + rcu_read_lock(); + hash_for_each_possible_rcu(s->context_to_sid, entry, list, + context->hash) { + if (context_cmp(&entry->context, context)) { + sid = entry->sid; + break; + } + } + rcu_read_unlock(); + return sid; +} + int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context) { struct sidtab_isid_entry *entry; @@ -47,14 +64,60 @@ int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context) entry = &s->isids[sid - 1]; - rc = context_cpy(&entry->context, context); + rc = context_cpy(&entry->leaf.context, context); if (rc) return rc; entry->set = 1; + + /* + * Multiple initial sids may map to the same context. Check that this + * context is not already represented in the context_to_sid hashtable + * to avoid duplicate entries and long linked lists upon hash + * collision. + */ + if (!context_to_sid(s, context)) { + entry->leaf.sid = sid; + hash_add(s->context_to_sid, &entry->leaf.list, context->hash); + } + return 0; } +int sidtab_hash_stats(struct sidtab *sidtab, char *page) +{ + int i; + int chain_len = 0; + int slots_used = 0; + int entries = 0; + int max_chain_len = 0; + int cur_bucket = 0; + struct sidtab_entry_leaf *entry; + + rcu_read_lock(); + hash_for_each_rcu(sidtab->context_to_sid, i, entry, list) { + entries++; + if (i == cur_bucket) { + chain_len++; + if (chain_len == 1) + slots_used++; + } else { + cur_bucket = i; + if (chain_len > max_chain_len) + max_chain_len = chain_len; + chain_len = 0; + } + } + rcu_read_unlock(); + + if (chain_len > max_chain_len) + max_chain_len = chain_len; + + return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n" + "longest chain: %d\n", entries, + slots_used, SIDTAB_HASH_BUCKETS, max_chain_len); +} + static u32 sidtab_level_from_count(u32 count) { u32 capacity = SIDTAB_LEAF_ENTRIES; @@ -88,7 +151,8 @@ static int sidtab_alloc_roots(struct sidtab *s, u32 level) return 0; } -static struct context *sidtab_do_lookup(struct sidtab *s, u32 index, int alloc) +static struct sidtab_entry_leaf *sidtab_do_lookup(struct sidtab *s, u32 index, + int alloc) { union sidtab_entry_inner *entry; u32 level, capacity_shift, leaf_index = index / SIDTAB_LEAF_ENTRIES; @@ -125,7 +189,7 @@ static struct context *sidtab_do_lookup(struct sidtab *s, u32 index, int alloc) if (!entry->ptr_leaf) return NULL; } - return &entry->ptr_leaf->entries[index % SIDTAB_LEAF_ENTRIES].context; + return &entry->ptr_leaf->entries[index % SIDTAB_LEAF_ENTRIES]; } static struct context *sidtab_lookup(struct sidtab *s, u32 index) @@ -136,12 +200,12 @@ static struct context *sidtab_lookup(struct sidtab *s, u32 index) if (index >= count) return NULL; - return sidtab_do_lookup(s, index, 0); + return &sidtab_do_lookup(s, index, 0)->context; } static struct context *sidtab_lookup_initial(struct sidtab *s, u32 sid) { - return s->isids[sid - 1].set ? &s->isids[sid - 1].context : NULL; + return s->isids[sid - 1].set ? &s->isids[sid - 1].leaf.context : NULL; } static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force) @@ -150,7 +214,7 @@ static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force) if (sid != 0) { if (sid > SECINITSID_NUM) - context = sidtab_lookup(s, sid - (SECINITSID_NUM + 1)); + context = sidtab_lookup(s, sid_to_index(sid)); else context = sidtab_lookup_initial(s, sid); if (context && (!context->len || force)) @@ -170,117 +234,30 @@ struct context *sidtab_search_force(struct sidtab *s, u32 sid) return sidtab_search_core(s, sid, 1); } -static int sidtab_find_context(union sidtab_entry_inner entry, - u32 *pos, u32 count, u32 level, - struct context *context, u32 *index) -{ - int rc; - u32 i; - - if (level != 0) { - struct sidtab_node_inner *node = entry.ptr_inner; - - i = 0; - while (i < SIDTAB_INNER_ENTRIES && *pos < count) { - rc = sidtab_find_context(node->entries[i], - pos, count, level - 1, - context, index); - if (rc == 0) - return 0; - i++; - } - } else { - struct sidtab_node_leaf *node = entry.ptr_leaf; - - i = 0; - while (i < SIDTAB_LEAF_ENTRIES && *pos < count) { - if (context_cmp(&node->entries[i].context, context)) { - *index = *pos; - return 0; - } - (*pos)++; - i++; - } - } - return -ENOENT; -} - -static void sidtab_rcache_update(struct sidtab *s, u32 index, u32 pos) -{ - while (pos > 0) { - WRITE_ONCE(s->rcache[pos], READ_ONCE(s->rcache[pos - 1])); - --pos; - } - WRITE_ONCE(s->rcache[0], index); -} - -static void sidtab_rcache_push(struct sidtab *s, u32 index) -{ - sidtab_rcache_update(s, index, SIDTAB_RCACHE_SIZE - 1); -} - -static int sidtab_rcache_search(struct sidtab *s, struct context *context, - u32 *index) -{ - u32 i; - - for (i = 0; i < SIDTAB_RCACHE_SIZE; i++) { - u32 v = READ_ONCE(s->rcache[i]); - - if (v >= SIDTAB_MAX) - continue; - - if (context_cmp(sidtab_do_lookup(s, v, 0), context)) { - sidtab_rcache_update(s, v, i); - *index = v; - return 0; - } - } - return -ENOENT; -} - -static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, - u32 *index) +int sidtab_context_to_sid(struct sidtab *s, struct context *context, + u32 *sid) { unsigned long flags; - u32 count, count_locked, level, pos; + u32 count; struct sidtab_convert_params *convert; - struct context *dst, *dst_convert; + struct sidtab_entry_leaf *dst, *dst_convert; int rc; - rc = sidtab_rcache_search(s, context, index); - if (rc == 0) - return 0; - - /* read entries only after reading count */ - count = smp_load_acquire(&s->count); - level = sidtab_level_from_count(count); - - pos = 0; - rc = sidtab_find_context(s->roots[level], &pos, count, level, - context, index); - if (rc == 0) { - sidtab_rcache_push(s, *index); + *sid = context_to_sid(s, context); + if (*sid) return 0; - } /* lock-free search failed: lock, re-search, and insert if not found */ spin_lock_irqsave(&s->lock, flags); + rc = 0; + *sid = context_to_sid(s, context); + if (*sid) + goto out_unlock; + + /* read entries only after reading count */ + count = smp_load_acquire(&s->count); convert = s->convert; - count_locked = s->count; - level = sidtab_level_from_count(count_locked); - - /* if count has changed before we acquired the lock, then catch up */ - while (count < count_locked) { - if (context_cmp(sidtab_do_lookup(s, count, 0), context)) { - sidtab_rcache_push(s, count); - *index = count; - rc = 0; - goto out_unlock; - } - ++count; - } /* bail out if we already reached max entries */ rc = -EOVERFLOW; @@ -293,7 +270,9 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, if (!dst) goto out_unlock; - rc = context_cpy(dst, context); + dst->sid = index_to_sid(count); + + rc = context_cpy(&dst->context, context); if (rc) goto out_unlock; @@ -305,29 +284,32 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context, rc = -ENOMEM; dst_convert = sidtab_do_lookup(convert->target, count, 1); if (!dst_convert) { - context_destroy(dst); + context_destroy(&dst->context); goto out_unlock; } - rc = convert->func(context, dst_convert, convert->args); + rc = convert->func(context, &dst_convert->context, + convert->args); if (rc) { - context_destroy(dst); + context_destroy(&dst->context); goto out_unlock; } - - /* at this point we know the insert won't fail */ + dst_convert->sid = index_to_sid(count); convert->target->count = count + 1; + + hash_add_rcu(convert->target->context_to_sid, + &dst_convert->list, dst_convert->context.hash); } if (context->len) pr_info("SELinux: Context %s is not valid (left unmapped).\n", context->str); - sidtab_rcache_push(s, count); - *index = count; + *sid = index_to_sid(count); - /* write entries before writing new count */ + /* write entries before updating count */ smp_store_release(&s->count, count + 1); + hash_add_rcu(s->context_to_sid, &dst->list, dst->context.hash); rc = 0; out_unlock: @@ -335,25 +317,19 @@ out_unlock: return rc; } -int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid) +static void sidtab_convert_hashtable(struct sidtab *s, u32 count) { - int rc; + struct sidtab_entry_leaf *entry; u32 i; - for (i = 0; i < SECINITSID_NUM; i++) { - struct sidtab_isid_entry *entry = &s->isids[i]; + for (i = 0; i < count; i++) { + entry = sidtab_do_lookup(s, i, 0); + entry->sid = index_to_sid(i); - if (entry->set && context_cmp(context, &entry->context)) { - *sid = i + 1; - return 0; - } - } + hash_add_rcu(s->context_to_sid, &entry->list, + entry->context.hash); - rc = sidtab_reverse_lookup(s, context, sid); - if (rc) - return rc; - *sid += SECINITSID_NUM + 1; - return 0; + } } static int sidtab_convert_tree(union sidtab_entry_inner *edst, @@ -400,6 +376,7 @@ static int sidtab_convert_tree(union sidtab_entry_inner *edst, } cond_resched(); } + return 0; } @@ -435,7 +412,7 @@ int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params) /* enable live convert of new entries */ s->convert = params; - /* we can safely do the rest of the conversion outside the lock */ + /* we can safely convert the tree outside the lock */ spin_unlock_irqrestore(&s->lock, flags); pr_info("SELinux: Converting %u SID table entries...\n", count); @@ -449,8 +426,17 @@ int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params) spin_lock_irqsave(&s->lock, flags); s->convert = NULL; spin_unlock_irqrestore(&s->lock, flags); + return rc; } - return rc; + /* + * The hashtable can also be modified in sidtab_context_to_sid() + * so we must re-acquire the lock here. + */ + spin_lock_irqsave(&s->lock, flags); + sidtab_convert_hashtable(params->target, count); + spin_unlock_irqrestore(&s->lock, flags); + + return 0; } static void sidtab_destroy_tree(union sidtab_entry_inner entry, u32 level) @@ -484,11 +470,16 @@ void sidtab_destroy(struct sidtab *s) for (i = 0; i < SECINITSID_NUM; i++) if (s->isids[i].set) - context_destroy(&s->isids[i].context); + context_destroy(&s->isids[i].leaf.context); level = SIDTAB_MAX_LEVEL; while (level && !s->roots[level].ptr_inner) --level; sidtab_destroy_tree(s->roots[level], level); + /* + * The context_to_sid hashtable's objects are all shared + * with the isids array and context tree, and so don't need + * to be cleaned up here. + */ } diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h index 1f4763141aa1..e2809401c417 100644 --- a/security/selinux/ss/sidtab.h +++ b/security/selinux/ss/sidtab.h @@ -13,11 +13,14 @@ #include <linux/spinlock_types.h> #include <linux/log2.h> +#include <linux/hashtable.h> #include "context.h" struct sidtab_entry_leaf { + u32 sid; struct context context; + struct hlist_node list; }; struct sidtab_node_inner; @@ -57,7 +60,7 @@ struct sidtab_node_inner { struct sidtab_isid_entry { int set; - struct context context; + struct sidtab_entry_leaf leaf; }; struct sidtab_convert_params { @@ -66,7 +69,8 @@ struct sidtab_convert_params { 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 { /* @@ -83,11 +87,11 @@ struct sidtab { struct sidtab_convert_params *convert; spinlock_t lock; - /* reverse lookup cache - access atomically via {READ|WRITE}_ONCE() */ - u32 rcache[SIDTAB_RCACHE_SIZE]; - /* 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); @@ -101,6 +105,8 @@ 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); + #endif /* _SS_SIDTAB_H_ */ |