aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--security/selinux/ss/mls.c24
-rw-r--r--security/selinux/ss/mls.h3
-rw-r--r--security/selinux/ss/services.c122
-rw-r--r--security/selinux/ss/sidtab.c563
-rw-r--r--security/selinux/ss/sidtab.h80
5 files changed, 468 insertions, 324 deletions
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 2fe459df3c85..18ba0c2328fb 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -436,16 +436,17 @@ int mls_setup_user_range(struct policydb *p,
/*
* Convert the MLS fields in the security context
- * structure `c' from the values specified in the
- * policy `oldp' to the values specified in the policy `newp'.
+ * structure `oldc' from the values specified in the
+ * policy `oldp' to the values specified in the policy `newp',
+ * storing the resulting context in `newc'.
*/
int mls_convert_context(struct policydb *oldp,
struct policydb *newp,
- struct context *c)
+ struct context *oldc,
+ struct context *newc)
{
struct level_datum *levdatum;
struct cat_datum *catdatum;
- struct ebitmap bitmap;
struct ebitmap_node *node;
int l, i;
@@ -455,28 +456,25 @@ int mls_convert_context(struct policydb *oldp,
for (l = 0; l < 2; l++) {
levdatum = hashtab_search(newp->p_levels.table,
sym_name(oldp, SYM_LEVELS,
- c->range.level[l].sens - 1));
+ oldc->range.level[l].sens - 1));
if (!levdatum)
return -EINVAL;
- c->range.level[l].sens = levdatum->level->sens;
+ newc->range.level[l].sens = levdatum->level->sens;
- ebitmap_init(&bitmap);
- ebitmap_for_each_positive_bit(&c->range.level[l].cat, node, i) {
+ ebitmap_for_each_positive_bit(&oldc->range.level[l].cat,
+ node, i) {
int rc;
catdatum = hashtab_search(newp->p_cats.table,
sym_name(oldp, SYM_CATS, i));
if (!catdatum)
return -EINVAL;
- rc = ebitmap_set_bit(&bitmap, catdatum->value - 1, 1);
+ rc = ebitmap_set_bit(&newc->range.level[l].cat,
+ catdatum->value - 1, 1);
if (rc)
return rc;
-
- cond_resched();
}
- ebitmap_destroy(&c->range.level[l].cat);
- c->range.level[l].cat = bitmap;
}
return 0;
diff --git a/security/selinux/ss/mls.h b/security/selinux/ss/mls.h
index 67093647576d..7954b1e60b64 100644
--- a/security/selinux/ss/mls.h
+++ b/security/selinux/ss/mls.h
@@ -46,7 +46,8 @@ int mls_range_set(struct context *context, struct mls_range *range);
int mls_convert_context(struct policydb *oldp,
struct policydb *newp,
- struct context *context);
+ struct context *oldc,
+ struct context *newc);
int mls_compute_sid(struct policydb *p,
struct context *scontext,
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 4ff4b0edbf6b..dd44126c8d14 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1907,19 +1907,16 @@ struct convert_context_args {
/*
* Convert the values in the security context
- * structure `c' from the values specified
+ * structure `oldc' from the values specified
* in the policy `p->oldp' to the values specified
- * in the policy `p->newp'. Verify that the
- * context is valid under the new policy.
+ * in the policy `p->newp', storing the new context
+ * in `newc'. Verify that the context is valid
+ * under the new policy.
*/
-static int convert_context(u32 key,
- struct context *c,
- void *p)
+static int convert_context(struct context *oldc, struct context *newc, void *p)
{
struct convert_context_args *args;
- struct context oldc;
struct ocontext *oc;
- struct mls_range *range;
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
@@ -1929,76 +1926,65 @@ static int convert_context(u32 key,
args = p;
- if (c->str) {
- struct context ctx;
-
- rc = -ENOMEM;
- s = kstrdup(c->str, GFP_KERNEL);
+ if (oldc->str) {
+ s = kstrdup(oldc->str, GFP_KERNEL);
if (!s)
- goto out;
+ return -ENOMEM;
rc = string_to_context_struct(args->newp, NULL, s,
- &ctx, SECSID_NULL);
- kfree(s);
- if (!rc) {
- pr_info("SELinux: Context %s became valid (mapped).\n",
- c->str);
- /* Replace string with mapped representation. */
- kfree(c->str);
- memcpy(c, &ctx, sizeof(*c));
- goto out;
- } else if (rc == -EINVAL) {
+ newc, SECSID_NULL);
+ if (rc == -EINVAL) {
/* Retain string representation for later mapping. */
- rc = 0;
- goto out;
- } else {
+ context_init(newc);
+ newc->str = s;
+ newc->len = oldc->len;
+ return 0;
+ }
+ kfree(s);
+ if (rc) {
/* Other error condition, e.g. ENOMEM. */
pr_err("SELinux: Unable to map context %s, rc = %d.\n",
- c->str, -rc);
- goto out;
+ oldc->str, -rc);
+ return rc;
}
+ pr_info("SELinux: Context %s became valid (mapped).\n",
+ oldc->str);
+ return 0;
}
- rc = context_cpy(&oldc, c);
- if (rc)
- goto out;
+ context_init(newc);
/* Convert the user. */
rc = -EINVAL;
usrdatum = hashtab_search(args->newp->p_users.table,
- sym_name(args->oldp, SYM_USERS, c->user - 1));
+ sym_name(args->oldp,
+ SYM_USERS, oldc->user - 1));
if (!usrdatum)
goto bad;
- c->user = usrdatum->value;
+ newc->user = usrdatum->value;
/* Convert the role. */
rc = -EINVAL;
role = hashtab_search(args->newp->p_roles.table,
- sym_name(args->oldp, SYM_ROLES, c->role - 1));
+ sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
if (!role)
goto bad;
- c->role = role->value;
+ newc->role = role->value;
/* Convert the type. */
rc = -EINVAL;
typdatum = hashtab_search(args->newp->p_types.table,
- sym_name(args->oldp, SYM_TYPES, c->type - 1));
+ sym_name(args->oldp,
+ SYM_TYPES, oldc->type - 1));
if (!typdatum)
goto bad;
- c->type = typdatum->value;
+ newc->type = typdatum->value;
/* Convert the MLS fields if dealing with MLS policies */
if (args->oldp->mls_enabled && args->newp->mls_enabled) {
- rc = mls_convert_context(args->oldp, args->newp, c);
+ rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
if (rc)
goto bad;
- } else if (args->oldp->mls_enabled && !args->newp->mls_enabled) {
- /*
- * Switching between MLS and non-MLS policy:
- * free any storage used by the MLS fields in the
- * context for all existing entries in the sidtab.
- */
- mls_context_destroy(c);
} else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
/*
* Switching between non-MLS and MLS policy:
@@ -2016,38 +2002,30 @@ static int convert_context(u32 key,
" the initial SIDs list\n");
goto bad;
}
- range = &oc->context[0].range;
- rc = mls_range_set(c, range);
+ rc = mls_range_set(newc, &oc->context[0].range);
if (rc)
goto bad;
}
/* Check the validity of the new context. */
- if (!policydb_context_isvalid(args->newp, c)) {
- rc = convert_context_handle_invalid_context(args->state,
- &oldc);
+ if (!policydb_context_isvalid(args->newp, newc)) {
+ rc = convert_context_handle_invalid_context(args->state, oldc);
if (rc)
goto bad;
}
- context_destroy(&oldc);
-
- rc = 0;
-out:
- return rc;
+ return 0;
bad:
/* Map old representation to string and save it. */
- rc = context_struct_to_string(args->oldp, &oldc, &s, &len);
+ rc = context_struct_to_string(args->oldp, oldc, &s, &len);
if (rc)
return rc;
- context_destroy(&oldc);
- context_destroy(c);
- c->str = s;
- c->len = len;
+ context_destroy(newc);
+ newc->str = s;
+ newc->len = len;
pr_info("SELinux: Context %s became invalid (unmapped).\n",
- c->str);
- rc = 0;
- goto out;
+ newc->str);
+ return 0;
}
static void security_load_policycaps(struct selinux_state *state)
@@ -2091,6 +2069,7 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
struct policydb *oldpolicydb, *newpolicydb;
struct selinux_mapping *oldmapping;
struct selinux_map newmap;
+ struct sidtab_convert_params convert_params;
struct convert_context_args args;
u32 seqno;
int rc = 0;
@@ -2147,12 +2126,6 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
goto out;
}
- oldsidtab = state->ss->sidtab;
-
-#if 0
- sidtab_hash_eval(oldsidtab, "sids");
-#endif
-
rc = policydb_read(newpolicydb, fp);
if (rc) {
kfree(newsidtab);
@@ -2184,6 +2157,8 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
goto err;
}
+ oldsidtab = state->ss->sidtab;
+
/*
* Convert the internal representations of contexts
* in the new SID table.
@@ -2191,7 +2166,12 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len)
args.state = state;
args.oldp = policydb;
args.newp = newpolicydb;
- rc = sidtab_convert(oldsidtab, newsidtab, convert_context, &args);
+
+ convert_params.func = convert_context;
+ convert_params.args = &args;
+ convert_params.target = newsidtab;
+
+ rc = sidtab_convert(oldsidtab, &convert_params);
if (rc) {
pr_err("SELinux: unable to convert the internal"
" representation of contexts in the new SID"
diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index e44e7cec630c..e63a90ff2728 100644
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -2,88 +2,41 @@
/*
* Implementation of the SID table type.
*
- * Author : Stephen Smalley, <sds@tycho.nsa.gov>
+ * Original author: Stephen Smalley, <sds@tycho.nsa.gov>
+ * Author: Ondrej Mosnacek, <omosnacek@gmail.com>
+ *
+ * Copyright (C) 2018 Red Hat, Inc.
*/
+#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
+#include <linux/sched.h>
#include <linux/spinlock.h>
-#include <linux/errno.h>
+#include <linux/atomic.h>
#include "flask.h"
#include "security.h"
#include "sidtab.h"
-#define SIDTAB_HASH(sid) \
-(sid & SIDTAB_HASH_MASK)
-
int sidtab_init(struct sidtab *s)
{
- int i;
+ u32 i;
- s->htable = kmalloc_array(SIDTAB_SIZE, sizeof(*s->htable), GFP_ATOMIC);
- if (!s->htable)
- return -ENOMEM;
+ memset(s->roots, 0, sizeof(s->roots));
+
+ for (i = 0; i < SIDTAB_RCACHE_SIZE; i++)
+ atomic_set(&s->rcache[i], -1);
for (i = 0; i < SECINITSID_NUM; i++)
s->isids[i].set = 0;
- for (i = 0; i < SIDTAB_SIZE; i++)
- s->htable[i] = NULL;
+ atomic_set(&s->count, 0);
- for (i = 0; i < SIDTAB_CACHE_LEN; i++)
- s->cache[i] = NULL;
+ s->convert = NULL;
- s->nel = 0;
- s->next_sid = 0;
- s->shutdown = 0;
spin_lock_init(&s->lock);
return 0;
}
-static int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
-{
- int hvalue;
- struct sidtab_node *prev, *cur, *newnode;
-
- if (!s)
- return -ENOMEM;
-
- hvalue = SIDTAB_HASH(sid);
- prev = NULL;
- cur = s->htable[hvalue];
- while (cur && sid > cur->sid) {
- prev = cur;
- cur = cur->next;
- }
-
- if (cur && sid == cur->sid)
- return -EEXIST;
-
- newnode = kmalloc(sizeof(*newnode), GFP_ATOMIC);
- if (!newnode)
- return -ENOMEM;
-
- newnode->sid = sid;
- if (context_cpy(&newnode->context, context)) {
- kfree(newnode);
- return -ENOMEM;
- }
-
- if (prev) {
- newnode->next = prev->next;
- wmb();
- prev->next = newnode;
- } else {
- newnode->next = s->htable[hvalue];
- wmb();
- s->htable[hvalue] = newnode;
- }
-
- s->nel++;
- if (sid >= s->next_sid)
- s->next_sid = sid + 1;
- return 0;
-}
-
int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)
{
struct sidtab_isid_entry *entry;
@@ -102,20 +55,90 @@ int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)
return 0;
}
-static struct context *sidtab_lookup(struct sidtab *s, u32 sid)
+static u32 sidtab_level_from_count(u32 count)
{
- int hvalue;
- struct sidtab_node *cur;
+ u32 capacity = SIDTAB_LEAF_ENTRIES;
+ u32 level = 0;
+
+ while (count > capacity) {
+ capacity <<= SIDTAB_INNER_SHIFT;
+ ++level;
+ }
+ return level;
+}
+
+static int sidtab_alloc_roots(struct sidtab *s, u32 level)
+{
+ u32 l;
+
+ if (!s->roots[0].ptr_leaf) {
+ s->roots[0].ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
+ GFP_ATOMIC);
+ if (!s->roots[0].ptr_leaf)
+ return -ENOMEM;
+ }
+ for (l = 1; l <= level; ++l)
+ if (!s->roots[l].ptr_inner) {
+ s->roots[l].ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
+ GFP_ATOMIC);
+ if (!s->roots[l].ptr_inner)
+ return -ENOMEM;
+ s->roots[l].ptr_inner->entries[0] = s->roots[l - 1];
+ }
+ return 0;
+}
+
+static struct context *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;
+
+ /* find the level of the subtree we need */
+ level = sidtab_level_from_count(index + 1);
+ capacity_shift = level * SIDTAB_INNER_SHIFT;
+
+ /* allocate roots if needed */
+ if (alloc && sidtab_alloc_roots(s, level) != 0)
+ return NULL;
+
+ /* lookup inside the subtree */
+ entry = &s->roots[level];
+ while (level != 0) {
+ capacity_shift -= SIDTAB_INNER_SHIFT;
+ --level;
+
+ entry = &entry->ptr_inner->entries[leaf_index >> capacity_shift];
+ leaf_index &= ((u32)1 << capacity_shift) - 1;
+
+ if (!entry->ptr_inner) {
+ if (alloc)
+ entry->ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
+ GFP_ATOMIC);
+ if (!entry->ptr_inner)
+ return NULL;
+ }
+ }
+ if (!entry->ptr_leaf) {
+ if (alloc)
+ entry->ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
+ GFP_ATOMIC);
+ if (!entry->ptr_leaf)
+ return NULL;
+ }
+ return &entry->ptr_leaf->entries[index % SIDTAB_LEAF_ENTRIES].context;
+}
- hvalue = SIDTAB_HASH(sid);
- cur = s->htable[hvalue];
- while (cur && sid > cur->sid)
- cur = cur->next;
+static struct context *sidtab_lookup(struct sidtab *s, u32 index)
+{
+ u32 count = (u32)atomic_read(&s->count);
- if (!cur || sid != cur->sid)
+ if (index >= count)
return NULL;
- return &cur->context;
+ /* read entries after reading count */
+ smp_rmb();
+
+ return sidtab_do_lookup(s, index, 0);
}
static struct context *sidtab_lookup_initial(struct sidtab *s, u32 sid)
@@ -127,9 +150,6 @@ static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
{
struct context *context;
- if (!s)
- return NULL;
-
if (sid != 0) {
if (sid > SECINITSID_NUM)
context = sidtab_lookup(s, sid - (SECINITSID_NUM + 1));
@@ -152,102 +172,69 @@ struct context *sidtab_search_force(struct sidtab *s, u32 sid)
return sidtab_search_core(s, sid, 1);
}
-static int sidtab_map(struct sidtab *s,
- int (*apply)(u32 sid,
- struct context *context,
- void *args),
- void *args)
+static int sidtab_find_context(union sidtab_entry_inner entry,
+ u32 *pos, u32 count, u32 level,
+ struct context *context, u32 *index)
{
- int i, rc = 0;
- struct sidtab_node *cur;
+ int rc;
+ u32 i;
- if (!s)
- goto out;
+ if (level != 0) {
+ struct sidtab_node_inner *node = entry.ptr_inner;
- for (i = 0; i < SIDTAB_SIZE; i++) {
- cur = s->htable[i];
- while (cur) {
- rc = apply(cur->sid, &cur->context, args);
- if (rc)
- goto out;
- cur = cur->next;
+ 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++;
}
}
-out:
- return rc;
+ return -ENOENT;
}
-/* Clone the SID into the new SID table. */
-static int clone_sid(u32 sid, struct context *context, void *arg)
+static void sidtab_rcache_update(struct sidtab *s, u32 index, u32 pos)
{
- struct sidtab *s = arg;
- return sidtab_insert(s, sid, context);
+ while (pos > 0) {
+ atomic_set(&s->rcache[pos], atomic_read(&s->rcache[pos - 1]));
+ --pos;
+ }
+ atomic_set(&s->rcache[0], (int)index);
}
-int sidtab_convert(struct sidtab *s, struct sidtab *news,
- int (*convert)(u32 sid,
- struct context *context,
- void *args),
- void *args)
+static void sidtab_rcache_push(struct sidtab *s, u32 index)
{
- unsigned long flags;
- int rc;
-
- spin_lock_irqsave(&s->lock, flags);
- s->shutdown = 1;
- spin_unlock_irqrestore(&s->lock, flags);
-
- rc = sidtab_map(s, clone_sid, news);
- if (rc)
- return rc;
-
- return sidtab_map(news, convert, args);
+ sidtab_rcache_update(s, index, SIDTAB_RCACHE_SIZE - 1);
}
-static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc)
+static int sidtab_rcache_search(struct sidtab *s, struct context *context,
+ u32 *index)
{
- BUG_ON(loc >= SIDTAB_CACHE_LEN);
+ u32 i;
- while (loc > 0) {
- s->cache[loc] = s->cache[loc - 1];
- loc--;
- }
- s->cache[0] = n;
-}
+ for (i = 0; i < SIDTAB_RCACHE_SIZE; i++) {
+ int v = atomic_read(&s->rcache[i]);
-static inline int sidtab_search_context(struct sidtab *s,
- struct context *context, u32 *sid)
-{
- int i;
- struct sidtab_node *cur;
-
- for (i = 0; i < SIDTAB_SIZE; i++) {
- cur = s->htable[i];
- while (cur) {
- if (context_cmp(&cur->context, context)) {
- sidtab_update_cache(s, cur, SIDTAB_CACHE_LEN - 1);
- *sid = cur->sid;
- return 0;
- }
- cur = cur->next;
- }
- }
- return -ENOENT;
-}
+ if (v < 0)
+ continue;
-static inline int sidtab_search_cache(struct sidtab *s, struct context *context,
- u32 *sid)
-{
- int i;
- struct sidtab_node *node;
-
- for (i = 0; i < SIDTAB_CACHE_LEN; i++) {
- node = s->cache[i];
- if (unlikely(!node))
- return -ENOENT;
- if (context_cmp(&node->context, context)) {
- sidtab_update_cache(s, node, i);
- *sid = node->sid;
+ if (context_cmp(sidtab_do_lookup(s, (u32)v, 0), context)) {
+ sidtab_rcache_update(s, (u32)v, i);
+ *index = (u32)v;
return 0;
}
}
@@ -255,38 +242,98 @@ static inline int sidtab_search_cache(struct sidtab *s, struct context *context,
}
static int sidtab_reverse_lookup(struct sidtab *s, struct context *context,
- u32 *sid)
+ u32 *index)
{
- int ret;
unsigned long flags;
+ u32 count = (u32)atomic_read(&s->count);
+ u32 count_locked, level, pos;
+ struct sidtab_convert_params *convert;
+ struct context *dst, *dst_convert;
+ int rc;
- ret = sidtab_search_cache(s, context, sid);
- if (ret)
- ret = sidtab_search_context(s, context, sid);
- if (ret) {
- spin_lock_irqsave(&s->lock, flags);
- /* Rescan now that we hold the lock. */
- ret = sidtab_search_context(s, context, sid);
- if (!ret)
- goto unlock_out;
- /* No SID exists for the context. Allocate a new one. */
- if (s->next_sid == (UINT_MAX - SECINITSID_NUM - 1) ||
- s->shutdown) {
- ret = -ENOMEM;
- goto unlock_out;
+ rc = sidtab_rcache_search(s, context, index);
+ if (rc == 0)
+ return 0;
+
+ level = sidtab_level_from_count(count);
+
+ /* read entries after reading count */
+ smp_rmb();
+
+ pos = 0;
+ rc = sidtab_find_context(s->roots[level], &pos, count, level,
+ context, index);
+ if (rc == 0) {
+ sidtab_rcache_push(s, *index);
+ return 0;
+ }
+
+ /* lock-free search failed: lock, re-search, and insert if not found */
+ spin_lock_irqsave(&s->lock, flags);
+
+ convert = s->convert;
+ count_locked = (u32)atomic_read(&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;
}
- *sid = s->next_sid++;
- if (context->len)
- pr_info("SELinux: Context %s is not valid (left unmapped).\n",
- context->str);
- ret = sidtab_insert(s, *sid, context);
- if (ret)
- s->next_sid--;
-unlock_out:
- spin_unlock_irqrestore(&s->lock, flags);
+ ++count;
+ }
+
+ /* insert context into new entry */
+ rc = -ENOMEM;
+ dst = sidtab_do_lookup(s, count, 1);
+ if (!dst)
+ goto out_unlock;
+
+ rc = context_cpy(dst, context);
+ if (rc)
+ goto out_unlock;
+
+ /*
+ * if we are building a new sidtab, we need to convert the context
+ * and insert it there as well
+ */
+ if (convert) {
+ rc = -ENOMEM;
+ dst_convert = sidtab_do_lookup(convert->target, count, 1);
+ if (!dst_convert) {
+ context_destroy(dst);
+ goto out_unlock;
+ }
+
+ rc = convert->func(context, dst_convert, convert->args);
+ if (rc) {
+ context_destroy(dst);
+ goto out_unlock;
+ }
+
+ /* at this point we know the insert won't fail */
+ atomic_set(&convert->target->count, count + 1);
}
- return ret;
+ if (context->len)
+ pr_info("SELinux: Context %s is not valid (left unmapped).\n",
+ context->str);
+
+ sidtab_rcache_push(s, count);
+ *index = count;
+
+ /* write entries before writing new count */
+ smp_wmb();
+
+ atomic_set(&s->count, count + 1);
+
+ rc = 0;
+out_unlock:
+ spin_unlock_irqrestore(&s->lock, flags);
+ return rc;
}
int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid)
@@ -310,57 +357,139 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid)
return 0;
}
-void sidtab_hash_eval(struct sidtab *h, char *tag)
+static int sidtab_convert_tree(union sidtab_entry_inner *edst,
+ union sidtab_entry_inner *esrc,
+ u32 *pos, u32 count, u32 level,
+ struct sidtab_convert_params *convert)
{
- int i, chain_len, slots_used, max_chain_len;
- struct sidtab_node *cur;
-
- slots_used = 0;
- max_chain_len = 0;
- for (i = 0; i < SIDTAB_SIZE; i++) {
- cur = h->htable[i];
- if (cur) {
- slots_used++;
- chain_len = 0;
- while (cur) {
- chain_len++;
- cur = cur->next;
- }
+ int rc;
+ u32 i;
- if (chain_len > max_chain_len)
- max_chain_len = chain_len;
+ if (level != 0) {
+ if (!edst->ptr_inner) {
+ edst->ptr_inner = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
+ GFP_KERNEL);
+ if (!edst->ptr_inner)
+ return -ENOMEM;
}
+ i = 0;
+ while (i < SIDTAB_INNER_ENTRIES && *pos < count) {
+ rc = sidtab_convert_tree(&edst->ptr_inner->entries[i],
+ &esrc->ptr_inner->entries[i],
+ pos, count, level - 1,
+ convert);
+ if (rc)
+ return rc;
+ i++;
+ }
+ } else {
+ if (!edst->ptr_leaf) {
+ edst->ptr_leaf = kzalloc(SIDTAB_NODE_ALLOC_SIZE,
+ GFP_KERNEL);
+ if (!edst->ptr_leaf)
+ return -ENOMEM;
+ }
+ i = 0;
+ while (i < SIDTAB_LEAF_ENTRIES && *pos < count) {
+ rc = convert->func(&esrc->ptr_leaf->entries[i].context,
+ &edst->ptr_leaf->entries[i].context,
+ convert->args);
+ if (rc)
+ return rc;
+ (*pos)++;
+ i++;
+ }
+ cond_resched();
+ }
+ return 0;
+}
+
+int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params)
+{
+ unsigned long flags;
+ u32 count, level, pos;
+ int rc;
+
+ spin_lock_irqsave(&s->lock, flags);
+
+ /* concurrent policy loads are not allowed */
+ if (s->convert) {
+ spin_unlock_irqrestore(&s->lock, flags);
+ return -EBUSY;
}
- pr_debug("%s: %d entries and %d/%d buckets used, longest "
- "chain length %d\n", tag, h->nel, slots_used, SIDTAB_SIZE,
- max_chain_len);
+ count = (u32)atomic_read(&s->count);
+ level = sidtab_level_from_count(count);
+
+ /* allocate last leaf in the new sidtab (to avoid race with
+ * live convert)
+ */
+ rc = sidtab_do_lookup(params->target, count - 1, 1) ? 0 : -ENOMEM;
+ if (rc) {
+ spin_unlock_irqrestore(&s->lock, flags);
+ return rc;
+ }
+
+ /* set count in case no new entries are added during conversion */
+ atomic_set(&params->target->count, count);
+
+ /* enable live convert of new entries */
+ s->convert = params;
+
+ /* we can safely do the rest of the conversion outside the lock */
+ spin_unlock_irqrestore(&s->lock, flags);
+
+ pr_info("SELinux: Converting %u SID table entries...\n", count);
+
+ /* convert all entries not covered by live convert */
+ pos = 0;
+ rc = sidtab_convert_tree(&params->target->roots[level],
+ &s->roots[level], &pos, count, level, params);
+ if (rc) {
+ /* we need to keep the old table - disable live convert */
+ spin_lock_irqsave(&s->lock, flags);
+ s->convert = NULL;
+ spin_unlock_irqrestore(&s->lock, flags);
+ }
+ return rc;
}
-void sidtab_destroy(struct sidtab *s)
+static void sidtab_destroy_tree(union sidtab_entry_inner entry, u32 level)
{
- int i;
- struct sidtab_node *cur, *temp;
+ u32 i;
+
+ if (level != 0) {
+ struct sidtab_node_inner *node = entry.ptr_inner;
+
+ if (!node)
+ return;
+
+ for (i = 0; i < SIDTAB_INNER_ENTRIES; i++)
+ sidtab_destroy_tree(node->entries[i], level - 1);
+ kfree(node);
+ } else {
+ struct sidtab_node_leaf *node = entry.ptr_leaf;
- if (!s)
- return;
+ if (!node)
+ return;
+
+ for (i = 0; i < SIDTAB_LEAF_ENTRIES; i++)
+ context_destroy(&node->entries[i].context);
+ kfree(node);
+ }
+}
+
+void sidtab_destroy(struct sidtab *s)
+{
+ u32 i, level;
for (i = 0; i < SECINITSID_NUM; i++)
if (s->isids[i].set)
context_destroy(&s->isids[i].context);
- for (i = 0; i < SIDTAB_SIZE; i++) {
- cur = s->htable[i];
- while (cur) {
- temp = cur;
- cur = cur->next;
- context_destroy(&temp->context);
- kfree(temp);
- }
- s->htable[i] = NULL;
- }
- kfree(s->htable);
- s->htable = NULL;
- s->nel = 0;
- s->next_sid = 1;
+ level = SIDTAB_MAX_LEVEL;
+ while (level && !s->roots[level].ptr_inner)
+ --level;
+
+ sidtab_destroy_tree(s->roots[level], level);
}
diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
index e657ae6bf996..bbd5c0d1f3bd 100644
--- a/security/selinux/ss/sidtab.h
+++ b/security/selinux/ss/sidtab.h
@@ -1,41 +1,82 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
- * A security identifier table (sidtab) is a hash table
+ * A security identifier table (sidtab) is a lookup table
* of security context structures indexed by SID value.
*
- * Author : Stephen Smalley, <sds@tycho.nsa.gov>
+ * 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 "context.h"
-struct sidtab_node {
- u32 sid; /* security identifier */
- struct context context; /* security context structure */
- struct sidtab_node *next;
+struct sidtab_entry_leaf {
+ struct context context;
+};
+
+struct sidtab_node_inner;
+struct sidtab_node_leaf;
+
+union sidtab_entry_inner {
+ struct sidtab_node_inner *ptr_inner;
+ struct sidtab_node_leaf *ptr_leaf;
};
-#define SIDTAB_HASH_BITS 7
-#define SIDTAB_HASH_BUCKETS (1 << SIDTAB_HASH_BITS)
-#define SIDTAB_HASH_MASK (SIDTAB_HASH_BUCKETS-1)
+/* 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_leaf))
-#define SIDTAB_SIZE SIDTAB_HASH_BUCKETS
+#define SIDTAB_MAX_BITS 31 /* limited to INT_MAX due to atomic_t range */
+#define SIDTAB_MAX (((u32)1 << SIDTAB_MAX_BITS) - 1)
+/* 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_leaf entries[SIDTAB_LEAF_ENTRIES];
+};
+
+struct sidtab_node_inner {
+ union sidtab_entry_inner entries[SIDTAB_INNER_ENTRIES];
+};
struct sidtab_isid_entry {
int set;
struct context context;
};
+struct sidtab_convert_params {
+ int (*func)(struct context *oldc, struct context *newc, void *args);
+ void *args;
+ struct sidtab *target;
+};
+
+#define SIDTAB_RCACHE_SIZE 3
+
struct sidtab {
- struct sidtab_node **htable;
- unsigned int nel; /* number of elements */
- unsigned int next_sid; /* next SID to allocate */
- unsigned char shutdown;
-#define SIDTAB_CACHE_LEN 3
- struct sidtab_node *cache[SIDTAB_CACHE_LEN];
+ union sidtab_entry_inner roots[SIDTAB_MAX_LEVEL + 1];
+ atomic_t count;
+ struct sidtab_convert_params *convert;
spinlock_t lock;
+ /* reverse lookup cache */
+ atomic_t rcache[SIDTAB_RCACHE_SIZE];
+
/* index == SID - 1 (no entry for SECSID_NULL) */
struct sidtab_isid_entry isids[SECINITSID_NUM];
};
@@ -45,15 +86,10 @@ 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);
-int sidtab_convert(struct sidtab *s, struct sidtab *news,
- int (*apply)(u32 sid,
- struct context *context,
- void *args),
- void *args);
+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_hash_eval(struct sidtab *h, char *tag);
void sidtab_destroy(struct sidtab *s);
#endif /* _SS_SIDTAB_H_ */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.