--- /dev/null
+/*
+ * Implementation of the SID table type.
+ *
+ * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
+ */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/errno.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;
+
+ s->htable = kmalloc(sizeof(*(s->htable)) * SIDTAB_SIZE, GFP_ATOMIC);
+ if (!s->htable)
+ return -ENOMEM;
+ for (i = 0; i < SIDTAB_SIZE; i++)
+ s->htable[i] = NULL;
+ s->nel = 0;
+ s->next_sid = 1;
+ s->shutdown = 0;
+ spin_lock_init(&s->lock);
+ return 0;
+}
+
+int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
+{
+ int hvalue, rc = 0;
+ struct sidtab_node *prev, *cur, *newnode;
+
+ if (!s) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ 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) {
+ rc = -EEXIST;
+ goto out;
+ }
+
+ newnode = kmalloc(sizeof(*newnode), GFP_ATOMIC);
+ if (newnode == NULL) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ newnode->sid = sid;
+ if (context_cpy(&newnode->context, context)) {
+ kfree(newnode);
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ 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;
+out:
+ return rc;
+}
+
+static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)
+{
+ int hvalue;
+ struct sidtab_node *cur;
+
+ if (!s)
+ return NULL;
+
+ hvalue = SIDTAB_HASH(sid);
+ cur = s->htable[hvalue];
+ while (cur && sid > cur->sid)
+ cur = cur->next;
+
+ if (force && cur && sid == cur->sid && cur->context.len)
+ return &cur->context;
+
+ if (cur == NULL || sid != cur->sid || cur->context.len) {
+ /* Remap invalid SIDs to the unlabeled SID. */
+ sid = SECINITSID_UNLABELED;
+ hvalue = SIDTAB_HASH(sid);
+ cur = s->htable[hvalue];
+ while (cur && sid > cur->sid)
+ cur = cur->next;
+ if (!cur || sid != cur->sid)
+ return NULL;
+ }
+
+ return &cur->context;
+}
+
+struct context *sidtab_search(struct sidtab *s, u32 sid)
+{
+ return sidtab_search_core(s, sid, 0);
+}
+
+struct context *sidtab_search_force(struct sidtab *s, u32 sid)
+{
+ return sidtab_search_core(s, sid, 1);
+}
+
+int sidtab_map(struct sidtab *s,
+ int (*apply) (u32 sid,
+ struct context *context,
+ void *args),
+ void *args)
+{
+ int i, rc = 0;
+ struct sidtab_node *cur;
+
+ if (!s)
+ goto out;
+
+ 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;
+ }
+ }
+out:
+ return rc;
+}
+
+static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc)
+{
+ BUG_ON(loc >= SIDTAB_CACHE_LEN);
+
+ while (loc > 0) {
+ s->cache[loc] = s->cache[loc - 1];
+ loc--;
+ }
+ s->cache[0] = n;
+}
+
+static inline u32 sidtab_search_context(struct sidtab *s,
+ struct context *context)
+{
+ 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);
+ return cur->sid;
+ }
+ cur = cur->next;
+ }
+ }
+ return 0;
+}
+
+static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context)
+{
+ int i;
+ struct sidtab_node *node;
+
+ for (i = 0; i < SIDTAB_CACHE_LEN; i++) {
+ node = s->cache[i];
+ if (unlikely(!node))
+ return 0;
+ if (context_cmp(&node->context, context)) {
+ sidtab_update_cache(s, node, i);
+ return node->sid;
+ }
+ }
+ return 0;
+}
+
+int sidtab_context_to_sid(struct sidtab *s,
+ struct context *context,
+ u32 *out_sid)
+{
+ u32 sid;
+ int ret = 0;
+ unsigned long flags;
+
+ *out_sid = SECSID_NULL;
+
+ sid = sidtab_search_cache(s, context);
+ if (!sid)
+ sid = sidtab_search_context(s, context);
+ if (!sid) {
+ spin_lock_irqsave(&s->lock, flags);
+ /* Rescan now that we hold the lock. */
+ sid = sidtab_search_context(s, context);
+ if (sid)
+ goto unlock_out;
+ /* No SID exists for the context. Allocate a new one. */
+ if (s->next_sid == UINT_MAX || s->shutdown) {
+ ret = -ENOMEM;
+ goto unlock_out;
+ }
+ sid = s->next_sid++;
+ if (context->len)
+ printk(KERN_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);
+ }
+
+ if (ret)
+ return ret;
+
+ *out_sid = sid;
+ return 0;
+}
+
+void sidtab_hash_eval(struct sidtab *h, char *tag)
+{
+ 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;
+ }
+
+ if (chain_len > max_chain_len)
+ max_chain_len = chain_len;
+ }
+ }
+
+ printk(KERN_DEBUG "%s: %d entries and %d/%d buckets used, longest "
+ "chain length %d\n", tag, h->nel, slots_used, SIDTAB_SIZE,
+ max_chain_len);
+}
+
+void sidtab_destroy(struct sidtab *s)
+{
+ int i;
+ struct sidtab_node *cur, *temp;
+
+ if (!s)
+ return;
+
+ 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;
+}
+
+void sidtab_set(struct sidtab *dst, struct sidtab *src)
+{
+ unsigned long flags;
+ int i;
+
+ spin_lock_irqsave(&src->lock, flags);
+ dst->htable = src->htable;
+ dst->nel = src->nel;
+ dst->next_sid = src->next_sid;
+ dst->shutdown = 0;
+ for (i = 0; i < SIDTAB_CACHE_LEN; i++)
+ dst->cache[i] = NULL;
+ spin_unlock_irqrestore(&src->lock, flags);
+}
+
+void sidtab_shutdown(struct sidtab *s)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&s->lock, flags);
+ s->shutdown = 1;
+ spin_unlock_irqrestore(&s->lock, flags);
+}
Code Review / kvmfornfv.git / blobdiff