--- /dev/null
+#include "audit.h"
+#include <linux/inotify.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+
+struct audit_tree;
+struct audit_chunk;
+
+struct audit_tree {
+ atomic_t count;
+ int goner;
+ struct audit_chunk *root;
+ struct list_head chunks;
+ struct list_head rules;
+ struct list_head list;
+ struct list_head same_root;
+ struct rcu_head head;
+ char pathname[];
+};
+
+struct audit_chunk {
+ struct list_head hash;
+ struct inotify_watch watch;
+ struct list_head trees; /* with root here */
+ int dead;
+ int count;
+ struct rcu_head head;
+ struct node {
+ struct list_head list;
+ struct audit_tree *owner;
+ unsigned index; /* index; upper bit indicates 'will prune' */
+ } owners[];
+};
+
+static LIST_HEAD(tree_list);
+static LIST_HEAD(prune_list);
+
+/*
+ * One struct chunk is attached to each inode of interest.
+ * We replace struct chunk on tagging/untagging.
+ * Rules have pointer to struct audit_tree.
+ * Rules have struct list_head rlist forming a list of rules over
+ * the same tree.
+ * References to struct chunk are collected at audit_inode{,_child}()
+ * time and used in AUDIT_TREE rule matching.
+ * These references are dropped at the same time we are calling
+ * audit_free_names(), etc.
+ *
+ * Cyclic lists galore:
+ * tree.chunks anchors chunk.owners[].list hash_lock
+ * tree.rules anchors rule.rlist audit_filter_mutex
+ * chunk.trees anchors tree.same_root hash_lock
+ * chunk.hash is a hash with middle bits of watch.inode as
+ * a hash function. RCU, hash_lock
+ *
+ * tree is refcounted; one reference for "some rules on rules_list refer to
+ * it", one for each chunk with pointer to it.
+ *
+ * chunk is refcounted by embedded inotify_watch.
+ *
+ * node.index allows to get from node.list to containing chunk.
+ * MSB of that sucker is stolen to mark taggings that we might have to
+ * revert - several operations have very unpleasant cleanup logics and
+ * that makes a difference. Some.
+ */
+
+static struct inotify_handle *rtree_ih;
+
+static struct audit_tree *alloc_tree(const char *s)
+{
+ struct audit_tree *tree;
+
+ tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL);
+ if (tree) {
+ atomic_set(&tree->count, 1);
+ tree->goner = 0;
+ INIT_LIST_HEAD(&tree->chunks);
+ INIT_LIST_HEAD(&tree->rules);
+ INIT_LIST_HEAD(&tree->list);
+ INIT_LIST_HEAD(&tree->same_root);
+ tree->root = NULL;
+ strcpy(tree->pathname, s);
+ }
+ return tree;
+}
+
+static inline void get_tree(struct audit_tree *tree)
+{
+ atomic_inc(&tree->count);
+}
+
+static void __put_tree(struct rcu_head *rcu)
+{
+ struct audit_tree *tree = container_of(rcu, struct audit_tree, head);
+ kfree(tree);
+}
+
+static inline void put_tree(struct audit_tree *tree)
+{
+ if (atomic_dec_and_test(&tree->count))
+ call_rcu(&tree->head, __put_tree);
+}
+
+/* to avoid bringing the entire thing in audit.h */
+const char *audit_tree_path(struct audit_tree *tree)
+{
+ return tree->pathname;
+}
+
+static struct audit_chunk *alloc_chunk(int count)
+{
+ struct audit_chunk *chunk;
+ size_t size;
+ int i;
+
+ size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);
+ chunk = kzalloc(size, GFP_KERNEL);
+ if (!chunk)
+ return NULL;
+
+ INIT_LIST_HEAD(&chunk->hash);
+ INIT_LIST_HEAD(&chunk->trees);
+ chunk->count = count;
+ for (i = 0; i < count; i++) {
+ INIT_LIST_HEAD(&chunk->owners[i].list);
+ chunk->owners[i].index = i;
+ }
+ inotify_init_watch(&chunk->watch);
+ return chunk;
+}
+
+static void __free_chunk(struct rcu_head *rcu)
+{
+ struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
+ int i;
+
+ for (i = 0; i < chunk->count; i++) {
+ if (chunk->owners[i].owner)
+ put_tree(chunk->owners[i].owner);
+ }
+ kfree(chunk);
+}
+
+static inline void free_chunk(struct audit_chunk *chunk)
+{
+ call_rcu(&chunk->head, __free_chunk);
+}
+
+void audit_put_chunk(struct audit_chunk *chunk)
+{
+ put_inotify_watch(&chunk->watch);
+}
+
+enum {HASH_SIZE = 128};
+static struct list_head chunk_hash_heads[HASH_SIZE];
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
+
+static inline struct list_head *chunk_hash(const struct inode *inode)
+{
+ unsigned long n = (unsigned long)inode / L1_CACHE_BYTES;
+ return chunk_hash_heads + n % HASH_SIZE;
+}
+
+/* hash_lock is held by caller */
+static void insert_hash(struct audit_chunk *chunk)
+{
+ struct list_head *list = chunk_hash(chunk->watch.inode);
+ list_add_rcu(&chunk->hash, list);
+}
+
+/* called under rcu_read_lock */
+struct audit_chunk *audit_tree_lookup(const struct inode *inode)
+{
+ struct list_head *list = chunk_hash(inode);
+ struct list_head *pos;
+
+ list_for_each_rcu(pos, list) {
+ struct audit_chunk *p = container_of(pos, struct audit_chunk, hash);
+ if (p->watch.inode == inode) {
+ get_inotify_watch(&p->watch);
+ return p;
+ }
+ }
+ return NULL;
+}
+
+int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
+{
+ int n;
+ for (n = 0; n < chunk->count; n++)
+ if (chunk->owners[n].owner == tree)
+ return 1;
+ return 0;
+}
+
+/* tagging and untagging inodes with trees */
+
+static void untag_chunk(struct audit_chunk *chunk, struct node *p)
+{
+ struct audit_chunk *new;
+ struct audit_tree *owner;
+ int size = chunk->count - 1;
+ int i, j;
+
+ mutex_lock(&chunk->watch.inode->inotify_mutex);
+ if (chunk->dead) {
+ mutex_unlock(&chunk->watch.inode->inotify_mutex);
+ return;
+ }
+
+ owner = p->owner;
+
+ if (!size) {
+ chunk->dead = 1;
+ spin_lock(&hash_lock);
+ list_del_init(&chunk->trees);
+ if (owner->root == chunk)
+ owner->root = NULL;
+ list_del_init(&p->list);
+ list_del_rcu(&chunk->hash);
+ spin_unlock(&hash_lock);
+ inotify_evict_watch(&chunk->watch);
+ mutex_unlock(&chunk->watch.inode->inotify_mutex);
+ put_inotify_watch(&chunk->watch);
+ return;
+ }
+
+ new = alloc_chunk(size);
+ if (!new)
+ goto Fallback;
+ if (inotify_clone_watch(&chunk->watch, &new->watch) < 0) {
+ free_chunk(new);
+ goto Fallback;
+ }
+
+ chunk->dead = 1;
+ spin_lock(&hash_lock);
+ list_replace_init(&chunk->trees, &new->trees);
+ if (owner->root == chunk) {
+ list_del_init(&owner->same_root);
+ owner->root = NULL;
+ }
+
+ for (i = j = 0; i < size; i++, j++) {
+ struct audit_tree *s;
+ if (&chunk->owners[j] == p) {
+ list_del_init(&p->list);
+ i--;
+ continue;
+ }
+ s = chunk->owners[j].owner;
+ new->owners[i].owner = s;
+ new->owners[i].index = chunk->owners[j].index - j + i;
+ if (!s) /* result of earlier fallback */
+ continue;
+ get_tree(s);
+ list_replace_init(&chunk->owners[i].list, &new->owners[j].list);
+ }
+
+ list_replace_rcu(&chunk->hash, &new->hash);
+ list_for_each_entry(owner, &new->trees, same_root)
+ owner->root = new;
+ spin_unlock(&hash_lock);
+ inotify_evict_watch(&chunk->watch);
+ mutex_unlock(&chunk->watch.inode->inotify_mutex);
+ put_inotify_watch(&chunk->watch);
+ return;
+
+Fallback:
+ // do the best we can
+ spin_lock(&hash_lock);
+ if (owner->root == chunk) {
+ list_del_init(&owner->same_root);
+ owner->root = NULL;
+ }
+ list_del_init(&p->list);
+ p->owner = NULL;
+ put_tree(owner);
+ spin_unlock(&hash_lock);
+ mutex_unlock(&chunk->watch.inode->inotify_mutex);
+}
+
+static int create_chunk(struct inode *inode, struct audit_tree *tree)
+{
+ struct audit_chunk *chunk = alloc_chunk(1);
+ if (!chunk)
+ return -ENOMEM;
+
+ if (inotify_add_watch(rtree_ih, &chunk->watch, inode, IN_IGNORED | IN_DELETE_SELF) < 0) {
+ free_chunk(chunk);
+ return -ENOSPC;
+ }
+
+ mutex_lock(&inode->inotify_mutex);
+ spin_lock(&hash_lock);
+ if (tree->goner) {
+ spin_unlock(&hash_lock);
+ chunk->dead = 1;
+ inotify_evict_watch(&chunk->watch);
+ mutex_unlock(&inode->inotify_mutex);
+ put_inotify_watch(&chunk->watch);
+ return 0;
+ }
+ chunk->owners[0].index = (1U << 31);
+ chunk->owners[0].owner = tree;
+ get_tree(tree);
+ list_add(&chunk->owners[0].list, &tree->chunks);
+ if (!tree->root) {
+ tree->root = chunk;
+ list_add(&tree->same_root, &chunk->trees);
+ }
+ insert_hash(chunk);
+ spin_unlock(&hash_lock);
+ mutex_unlock(&inode->inotify_mutex);
+ return 0;
+}
+
+/* the first tagged inode becomes root of tree */
+static int tag_chunk(struct inode *inode, struct audit_tree *tree)
+{
+ struct inotify_watch *watch;
+ struct audit_tree *owner;
+ struct audit_chunk *chunk, *old;
+ struct node *p;
+ int n;
+
+ if (inotify_find_watch(rtree_ih, inode, &watch) < 0)
+ return create_chunk(inode, tree);
+
+ old = container_of(watch, struct audit_chunk, watch);
+
+ /* are we already there? */
+ spin_lock(&hash_lock);
+ for (n = 0; n < old->count; n++) {
+ if (old->owners[n].owner == tree) {
+ spin_unlock(&hash_lock);
+ put_inotify_watch(watch);
+ return 0;
+ }
+ }
+ spin_unlock(&hash_lock);
+
+ chunk = alloc_chunk(old->count + 1);
+ if (!chunk)
+ return -ENOMEM;
+
+ mutex_lock(&inode->inotify_mutex);
+ if (inotify_clone_watch(&old->watch, &chunk->watch) < 0) {
+ mutex_unlock(&inode->inotify_mutex);
+ free_chunk(chunk);
+ return -ENOSPC;
+ }
+ spin_lock(&hash_lock);
+ if (tree->goner) {
+ spin_unlock(&hash_lock);
+ chunk->dead = 1;
+ inotify_evict_watch(&chunk->watch);
+ mutex_unlock(&inode->inotify_mutex);
+ put_inotify_watch(&chunk->watch);
+ return 0;
+ }
+ list_replace_init(&old->trees, &chunk->trees);
+ for (n = 0, p = chunk->owners; n < old->count; n++, p++) {
+ struct audit_tree *s = old->owners[n].owner;
+ p->owner = s;
+ p->index = old->owners[n].index;
+ if (!s) /* result of fallback in untag */
+ continue;
+ get_tree(s);
+ list_replace_init(&old->owners[n].list, &p->list);
+ }
+ p->index = (chunk->count - 1) | (1U<<31);
+ p->owner = tree;
+ get_tree(tree);
+ list_add(&p->list, &tree->chunks);
+ list_replace_rcu(&old->hash, &chunk->hash);
+ list_for_each_entry(owner, &chunk->trees, same_root)
+ owner->root = chunk;
+ old->dead = 1;
+ if (!tree->root) {
+ tree->root = chunk;
+ list_add(&tree->same_root, &chunk->trees);
+ }
+ spin_unlock(&hash_lock);
+ inotify_evict_watch(&old->watch);
+ mutex_unlock(&inode->inotify_mutex);
+ put_inotify_watch(&old->watch);
+ return 0;
+}
+
+static struct audit_chunk *find_chunk(struct node *p)
+{
+ int index = p->index & ~(1U<<31);
+ p -= index;
+ return container_of(p, struct audit_chunk, owners[0]);
+}
+
+static void kill_rules(struct audit_tree *tree)
+{
+ struct audit_krule *rule, *next;
+ struct audit_entry *entry;
+ struct audit_buffer *ab;
+
+ list_for_each_entry_safe(rule, next, &tree->rules, rlist) {
+ entry = container_of(rule, struct audit_entry, rule);
+
+ list_del_init(&rule->rlist);
+ if (rule->tree) {
+ /* not a half-baked one */
+ ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+ audit_log_format(ab, "op=remove rule dir=");
+ audit_log_untrustedstring(ab, rule->tree->pathname);
+ if (rule->filterkey) {
+ audit_log_format(ab, " key=");
+ audit_log_untrustedstring(ab, rule->filterkey);
+ } else
+ audit_log_format(ab, " key=(null)");
+ audit_log_format(ab, " list=%d res=1", rule->listnr);
+ audit_log_end(ab);
+ rule->tree = NULL;
+ list_del_rcu(&entry->list);
+ call_rcu(&entry->rcu, audit_free_rule_rcu);
+ }
+ }
+}
+
+/*
+ * finish killing struct audit_tree
+ */
+static void prune_one(struct audit_tree *victim)
+{
+ spin_lock(&hash_lock);
+ while (!list_empty(&victim->chunks)) {
+ struct node *p;
+ struct audit_chunk *chunk;
+
+ p = list_entry(victim->chunks.next, struct node, list);
+ chunk = find_chunk(p);
+ get_inotify_watch(&chunk->watch);
+ spin_unlock(&hash_lock);
+
+ untag_chunk(chunk, p);
+
+ put_inotify_watch(&chunk->watch);
+ spin_lock(&hash_lock);
+ }
+ spin_unlock(&hash_lock);
+ put_tree(victim);
+}
+
+/* trim the uncommitted chunks from tree */
+
+static void trim_marked(struct audit_tree *tree)
+{
+ struct list_head *p, *q;
+ spin_lock(&hash_lock);
+ if (tree->goner) {
+ spin_unlock(&hash_lock);
+ return;
+ }
+ /* reorder */
+ for (p = tree->chunks.next; p != &tree->chunks; p = q) {
+ struct node *node = list_entry(p, struct node, list);
+ q = p->next;
+ if (node->index & (1U<<31)) {
+ list_del_init(p);
+ list_add(p, &tree->chunks);
+ }
+ }
+
+ while (!list_empty(&tree->chunks)) {
+ struct node *node;
+ struct audit_chunk *chunk;
+
+ node = list_entry(tree->chunks.next, struct node, list);
+
+ /* have we run out of marked? */
+ if (!(node->index & (1U<<31)))
+ break;
+
+ chunk = find_chunk(node);
+ get_inotify_watch(&chunk->watch);
+ spin_unlock(&hash_lock);
+
+ untag_chunk(chunk, node);
+
+ put_inotify_watch(&chunk->watch);
+ spin_lock(&hash_lock);
+ }
+ if (!tree->root && !tree->goner) {
+ tree->goner = 1;
+ spin_unlock(&hash_lock);
+ mutex_lock(&audit_filter_mutex);
+ kill_rules(tree);
+ list_del_init(&tree->list);
+ mutex_unlock(&audit_filter_mutex);
+ prune_one(tree);
+ } else {
+ spin_unlock(&hash_lock);
+ }
+}
+
+/* called with audit_filter_mutex */
+int audit_remove_tree_rule(struct audit_krule *rule)
+{
+ struct audit_tree *tree;
+ tree = rule->tree;
+ if (tree) {
+ spin_lock(&hash_lock);
+ list_del_init(&rule->rlist);
+ if (list_empty(&tree->rules) && !tree->goner) {
+ tree->root = NULL;
+ list_del_init(&tree->same_root);
+ tree->goner = 1;
+ list_move(&tree->list, &prune_list);
+ rule->tree = NULL;
+ spin_unlock(&hash_lock);
+ audit_schedule_prune();
+ return 1;
+ }
+ rule->tree = NULL;
+ spin_unlock(&hash_lock);
+ return 1;
+ }
+ return 0;
+}
+
+void audit_trim_trees(void)
+{
+ struct list_head cursor;
+
+ mutex_lock(&audit_filter_mutex);
+ list_add(&cursor, &tree_list);
+ while (cursor.next != &tree_list) {
+ struct audit_tree *tree;
+ struct nameidata nd;
+ struct vfsmount *root_mnt;
+ struct node *node;
+ struct list_head list;
+ int err;
+
+ tree = container_of(cursor.next, struct audit_tree, list);
+ get_tree(tree);
+ list_del(&cursor);
+ list_add(&cursor, &tree->list);
+ mutex_unlock(&audit_filter_mutex);
+
+ err = path_lookup(tree->pathname, 0, &nd);
+ if (err)
+ goto skip_it;
+
+ root_mnt = collect_mounts(nd.mnt, nd.dentry);
+ path_release(&nd);
+ if (!root_mnt)
+ goto skip_it;
+
+ list_add_tail(&list, &root_mnt->mnt_list);
+ spin_lock(&hash_lock);
+ list_for_each_entry(node, &tree->chunks, list) {
+ struct audit_chunk *chunk = find_chunk(node);
+ struct inode *inode = chunk->watch.inode;
+ struct vfsmount *mnt;
+ node->index |= 1U<<31;
+ list_for_each_entry(mnt, &list, mnt_list) {
+ if (mnt->mnt_root->d_inode == inode) {
+ node->index &= ~(1U<<31);
+ break;
+ }
+ }
+ }
+ spin_unlock(&hash_lock);
+ trim_marked(tree);
+ put_tree(tree);
+ list_del_init(&list);
+ drop_collected_mounts(root_mnt);
+skip_it:
+ mutex_lock(&audit_filter_mutex);
+ }
+ list_del(&cursor);
+ mutex_unlock(&audit_filter_mutex);
+}
+
+static int is_under(struct vfsmount *mnt, struct dentry *dentry,
+ struct nameidata *nd)
+{
+ if (mnt != nd->mnt) {
+ for (;;) {
+ if (mnt->mnt_parent == mnt)
+ return 0;
+ if (mnt->mnt_parent == nd->mnt)
+ break;
+ mnt = mnt->mnt_parent;
+ }
+ dentry = mnt->mnt_mountpoint;
+ }
+ return is_subdir(dentry, nd->dentry);
+}
+
+int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
+{
+
+ if (pathname[0] != '/' ||
+ rule->listnr != AUDIT_FILTER_EXIT ||
+ op & ~AUDIT_EQUAL ||
+ rule->inode_f || rule->watch || rule->tree)
+ return -EINVAL;
+ rule->tree = alloc_tree(pathname);
+ if (!rule->tree)
+ return -ENOMEM;
+ return 0;
+}
+
+void audit_put_tree(struct audit_tree *tree)
+{
+ put_tree(tree);
+}
+
+/* called with audit_filter_mutex */
+int audit_add_tree_rule(struct audit_krule *rule)
+{
+ struct audit_tree *seed = rule->tree, *tree;
+ struct nameidata nd;
+ struct vfsmount *mnt, *p;
+ struct list_head list;
+ int err;
+
+ list_for_each_entry(tree, &tree_list, list) {
+ if (!strcmp(seed->pathname, tree->pathname)) {
+ put_tree(seed);
+ rule->tree = tree;
+ list_add(&rule->rlist, &tree->rules);
+ return 0;
+ }
+ }
+ tree = seed;
+ list_add(&tree->list, &tree_list);
+ list_add(&rule->rlist, &tree->rules);
+ /* do not set rule->tree yet */
+ mutex_unlock(&audit_filter_mutex);
+
+ err = path_lookup(tree->pathname, 0, &nd);
+ if (err)
+ goto Err;
+ mnt = collect_mounts(nd.mnt, nd.dentry);
+ path_release(&nd);
+ if (!mnt) {
+ err = -ENOMEM;
+ goto Err;
+ }
+ list_add_tail(&list, &mnt->mnt_list);
+
+ get_tree(tree);
+ list_for_each_entry(p, &list, mnt_list) {
+ err = tag_chunk(p->mnt_root->d_inode, tree);
+ if (err)
+ break;
+ }
+
+ list_del(&list);
+ drop_collected_mounts(mnt);
+
+ if (!err) {
+ struct node *node;
+ spin_lock(&hash_lock);
+ list_for_each_entry(node, &tree->chunks, list)
+ node->index &= ~(1U<<31);
+ spin_unlock(&hash_lock);
+ } else {
+ trim_marked(tree);
+ goto Err;
+ }
+
+ mutex_lock(&audit_filter_mutex);
+ if (list_empty(&rule->rlist)) {
+ put_tree(tree);
+ return -ENOENT;
+ }
+ rule->tree = tree;
+ put_tree(tree);
+
+ return 0;
+Err:
+ mutex_lock(&audit_filter_mutex);
+ list_del_init(&tree->list);
+ list_del_init(&tree->rules);
+ put_tree(tree);
+ return err;
+}
+
+int audit_tag_tree(char *old, char *new)
+{
+ struct list_head cursor, barrier;
+ int failed = 0;
+ struct nameidata nd;
+ struct vfsmount *tagged;
+ struct list_head list;
+ struct vfsmount *mnt;
+ struct dentry *dentry;
+ int err;
+
+ err = path_lookup(new, 0, &nd);
+ if (err)
+ return err;
+ tagged = collect_mounts(nd.mnt, nd.dentry);
+ path_release(&nd);
+ if (!tagged)
+ return -ENOMEM;
+
+ err = path_lookup(old, 0, &nd);
+ if (err) {
+ drop_collected_mounts(tagged);
+ return err;
+ }
+ mnt = mntget(nd.mnt);
+ dentry = dget(nd.dentry);
+ path_release(&nd);
+
+ if (dentry == tagged->mnt_root && dentry == mnt->mnt_root)
+ follow_up(&mnt, &dentry);
+
+ list_add_tail(&list, &tagged->mnt_list);
+
+ mutex_lock(&audit_filter_mutex);
+ list_add(&barrier, &tree_list);
+ list_add(&cursor, &barrier);
+
+ while (cursor.next != &tree_list) {
+ struct audit_tree *tree;
+ struct vfsmount *p;
+
+ tree = container_of(cursor.next, struct audit_tree, list);
+ get_tree(tree);
+ list_del(&cursor);
+ list_add(&cursor, &tree->list);
+ mutex_unlock(&audit_filter_mutex);
+
+ err = path_lookup(tree->pathname, 0, &nd);
+ if (err) {
+ put_tree(tree);
+ mutex_lock(&audit_filter_mutex);
+ continue;
+ }
+
+ spin_lock(&vfsmount_lock);
+ if (!is_under(mnt, dentry, &nd)) {
+ spin_unlock(&vfsmount_lock);
+ path_release(&nd);
+ put_tree(tree);
+ mutex_lock(&audit_filter_mutex);
+ continue;
+ }
+ spin_unlock(&vfsmount_lock);
+ path_release(&nd);
+
+ list_for_each_entry(p, &list, mnt_list) {
+ failed = tag_chunk(p->mnt_root->d_inode, tree);
+ if (failed)
+ break;
+ }
+
+ if (failed) {
+ put_tree(tree);
+ mutex_lock(&audit_filter_mutex);
+ break;
+ }
+
+ mutex_lock(&audit_filter_mutex);
+ spin_lock(&hash_lock);
+ if (!tree->goner) {
+ list_del(&tree->list);
+ list_add(&tree->list, &tree_list);
+ }
+ spin_unlock(&hash_lock);
+ put_tree(tree);
+ }
+
+ while (barrier.prev != &tree_list) {
+ struct audit_tree *tree;
+
+ tree = container_of(barrier.prev, struct audit_tree, list);
+ get_tree(tree);
+ list_del(&tree->list);
+ list_add(&tree->list, &barrier);
+ mutex_unlock(&audit_filter_mutex);
+
+ if (!failed) {
+ struct node *node;
+ spin_lock(&hash_lock);
+ list_for_each_entry(node, &tree->chunks, list)
+ node->index &= ~(1U<<31);
+ spin_unlock(&hash_lock);
+ } else {
+ trim_marked(tree);
+ }
+
+ put_tree(tree);
+ mutex_lock(&audit_filter_mutex);
+ }
+ list_del(&barrier);
+ list_del(&cursor);
+ list_del(&list);
+ mutex_unlock(&audit_filter_mutex);
+ dput(dentry);
+ mntput(mnt);
+ drop_collected_mounts(tagged);
+ return failed;
+}
+
+/*
+ * That gets run when evict_chunk() ends up needing to kill audit_tree.
+ * Runs from a separate thread, with audit_cmd_mutex held.
+ */
+void audit_prune_trees(void)
+{
+ mutex_lock(&audit_filter_mutex);
+
+ while (!list_empty(&prune_list)) {
+ struct audit_tree *victim;
+
+ victim = list_entry(prune_list.next, struct audit_tree, list);
+ list_del_init(&victim->list);
+
+ mutex_unlock(&audit_filter_mutex);
+
+ prune_one(victim);
+
+ mutex_lock(&audit_filter_mutex);
+ }
+
+ mutex_unlock(&audit_filter_mutex);
+}
+
+/*
+ * Here comes the stuff asynchronous to auditctl operations
+ */
+
+/* inode->inotify_mutex is locked */
+static void evict_chunk(struct audit_chunk *chunk)
+{
+ struct audit_tree *owner;
+ int n;
+
+ if (chunk->dead)
+ return;
+
+ chunk->dead = 1;
+ mutex_lock(&audit_filter_mutex);
+ spin_lock(&hash_lock);
+ while (!list_empty(&chunk->trees)) {
+ owner = list_entry(chunk->trees.next,
+ struct audit_tree, same_root);
+ owner->goner = 1;
+ owner->root = NULL;
+ list_del_init(&owner->same_root);
+ spin_unlock(&hash_lock);
+ kill_rules(owner);
+ list_move(&owner->list, &prune_list);
+ audit_schedule_prune();
+ spin_lock(&hash_lock);
+ }
+ list_del_rcu(&chunk->hash);
+ for (n = 0; n < chunk->count; n++)
+ list_del_init(&chunk->owners[n].list);
+ spin_unlock(&hash_lock);
+ mutex_unlock(&audit_filter_mutex);
+}
+
+static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
+ u32 cookie, const char *dname, struct inode *inode)
+{
+ struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
+
+ if (mask & IN_IGNORED) {
+ evict_chunk(chunk);
+ put_inotify_watch(watch);
+ }
+}
+
+static void destroy_watch(struct inotify_watch *watch)
+{
+ struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
+ free_chunk(chunk);
+}
+
+static const struct inotify_operations rtree_inotify_ops = {
+ .handle_event = handle_event,
+ .destroy_watch = destroy_watch,
+};
+
+static int __init audit_tree_init(void)
+{
+ int i;
+
+ rtree_ih = inotify_init(&rtree_inotify_ops);
+ if (IS_ERR(rtree_ih))
+ audit_panic("cannot initialize inotify handle for rectree watches");
+
+ for (i = 0; i < HASH_SIZE; i++)
+ INIT_LIST_HEAD(&chunk_hash_heads[i]);
+
+ return 0;
+}
+__initcall(audit_tree_init);
#endif
};
-static DEFINE_MUTEX(audit_filter_mutex);
+DEFINE_MUTEX(audit_filter_mutex);
/* Inotify handle */
extern struct inotify_handle *audit_ih;
kfree(e);
}
-static inline void audit_free_rule_rcu(struct rcu_head *head)
+void audit_free_rule_rcu(struct rcu_head *head)
{
struct audit_entry *e = container_of(head, struct audit_entry, rcu);
audit_free_rule(e);
/* Unpack a filter field's string representation from user-space
* buffer. */
-static char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
+char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
{
char *str;
struct audit_field *f)
{
if (krule->listnr != AUDIT_FILTER_EXIT ||
- krule->watch || krule->inode_f)
+ krule->watch || krule->inode_f || krule->tree)
return -EINVAL;
krule->inode_f = f;
if (path[0] != '/' || path[len-1] == '/' ||
krule->listnr != AUDIT_FILTER_EXIT ||
op & ~AUDIT_EQUAL ||
- krule->inode_f || krule->watch) /* 1 inode # per rule, for hash */
+ krule->inode_f || krule->watch || krule->tree)
return -EINVAL;
watch = audit_init_watch(path);
goto exit_free;
}
break;
+ case AUDIT_DIR:
+ str = audit_unpack_string(&bufp, &remain, f->val);
+ if (IS_ERR(str))
+ goto exit_free;
+ entry->rule.buflen += f->val;
+
+ err = audit_make_tree(&entry->rule, str, f->op);
+ kfree(str);
+ if (err)
+ goto exit_free;
+ break;
case AUDIT_INODE:
err = audit_to_inode(&entry->rule, f);
if (err)
}
/* Pack a filter field's string representation into data block. */
-static inline size_t audit_pack_string(void **bufp, char *str)
+static inline size_t audit_pack_string(void **bufp, const char *str)
{
size_t len = strlen(str);
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->watch->path);
break;
+ case AUDIT_DIR:
+ data->buflen += data->values[i] =
+ audit_pack_string(&bufp,
+ audit_tree_path(krule->tree));
+ break;
case AUDIT_FILTERKEY:
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->filterkey);
if (strcmp(a->watch->path, b->watch->path))
return 1;
break;
+ case AUDIT_DIR:
+ if (strcmp(audit_tree_path(a->tree),
+ audit_tree_path(b->tree)))
+ return 1;
+ break;
case AUDIT_FILTERKEY:
/* both filterkeys exist based on above type compare */
if (strcmp(a->filterkey, b->filterkey))
new->inode_f = old->inode_f;
new->watch = NULL;
new->field_count = old->field_count;
+ /*
+ * note that we are OK with not refcounting here; audit_match_tree()
+ * never dereferences tree and we can't get false positives there
+ * since we'd have to have rule gone from the list *and* removed
+ * before the chunks found by lookup had been allocated, i.e. before
+ * the beginning of list scan.
+ */
+ new->tree = old->tree;
memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
/* deep copy this information, updating the se_rule fields, because
struct audit_entry *e;
struct audit_field *inode_f = entry->rule.inode_f;
struct audit_watch *watch = entry->rule.watch;
+ struct audit_tree *tree = entry->rule.tree;
struct nameidata *ndp = NULL, *ndw = NULL;
int h, err;
#ifdef CONFIG_AUDITSYSCALL
mutex_unlock(&audit_filter_mutex);
if (e) {
err = -EEXIST;
+ /* normally audit_add_tree_rule() will free it on failure */
+ if (tree)
+ audit_put_tree(tree);
goto error;
}
h = audit_hash_ino((u32)watch->ino);
list = &audit_inode_hash[h];
}
+ if (tree) {
+ err = audit_add_tree_rule(&entry->rule);
+ if (err) {
+ mutex_unlock(&audit_filter_mutex);
+ goto error;
+ }
+ }
if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
list_add_rcu(&entry->list, list);
struct audit_entry *e;
struct audit_field *inode_f = entry->rule.inode_f;
struct audit_watch *watch, *tmp_watch = entry->rule.watch;
+ struct audit_tree *tree = entry->rule.tree;
LIST_HEAD(inotify_list);
int h, ret = 0;
#ifdef CONFIG_AUDITSYSCALL
}
}
+ if (e->rule.tree)
+ audit_remove_tree_rule(&e->rule);
+
list_del_rcu(&e->list);
call_rcu(&e->rcu, audit_free_rule_rcu);
out:
if (tmp_watch)
audit_put_watch(tmp_watch); /* match initial get */
+ if (tree)
+ audit_put_tree(tree); /* that's the temporary one */
return ret;
}
{
struct audit_entry *entry, *n, *nentry;
struct audit_watch *watch;
+ struct audit_tree *tree;
int i, err = 0;
/* audit_filter_mutex synchronizes the writers */
continue;
watch = entry->rule.watch;
+ tree = entry->rule.tree;
nentry = audit_dupe_rule(&entry->rule, watch);
if (unlikely(IS_ERR(nentry))) {
/* save the first error encountered for the
list_add(&nentry->rule.rlist,
&watch->rules);
list_del(&entry->rule.rlist);
- }
+ } else if (tree)
+ list_replace_init(&entry->rule.rlist,
+ &nentry->rule.rlist);
list_replace_rcu(&entry->list, &nentry->list);
}
call_rcu(&entry->rcu, audit_free_rule_rcu);
#include <linux/binfmts.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
+#include <linux/inotify.h>
#include "audit.h"
int pid_count;
};
+struct audit_tree_refs {
+ struct audit_tree_refs *next;
+ struct audit_chunk *c[31];
+};
+
/* The per-task audit context. */
struct audit_context {
int dummy; /* must be the first element */
pid_t target_pid;
u32 target_sid;
+ struct audit_tree_refs *trees, *first_trees;
+ int tree_count;
+
#if AUDIT_DEBUG
int put_count;
int ino_count;
}
}
+/*
+ * We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
+ * ->first_trees points to its beginning, ->trees - to the current end of data.
+ * ->tree_count is the number of free entries in array pointed to by ->trees.
+ * Original condition is (NULL, NULL, 0); as soon as it grows we never revert to NULL,
+ * "empty" becomes (p, p, 31) afterwards. We don't shrink the list (and seriously,
+ * it's going to remain 1-element for almost any setup) until we free context itself.
+ * References in it _are_ dropped - at the same time we free/drop aux stuff.
+ */
+
+#ifdef CONFIG_AUDIT_TREE
+static int put_tree_ref(struct audit_context *ctx, struct audit_chunk *chunk)
+{
+ struct audit_tree_refs *p = ctx->trees;
+ int left = ctx->tree_count;
+ if (likely(left)) {
+ p->c[--left] = chunk;
+ ctx->tree_count = left;
+ return 1;
+ }
+ if (!p)
+ return 0;
+ p = p->next;
+ if (p) {
+ p->c[30] = chunk;
+ ctx->trees = p;
+ ctx->tree_count = 30;
+ return 1;
+ }
+ return 0;
+}
+
+static int grow_tree_refs(struct audit_context *ctx)
+{
+ struct audit_tree_refs *p = ctx->trees;
+ ctx->trees = kzalloc(sizeof(struct audit_tree_refs), GFP_KERNEL);
+ if (!ctx->trees) {
+ ctx->trees = p;
+ return 0;
+ }
+ if (p)
+ p->next = ctx->trees;
+ else
+ ctx->first_trees = ctx->trees;
+ ctx->tree_count = 31;
+ return 1;
+}
+#endif
+
+static void unroll_tree_refs(struct audit_context *ctx,
+ struct audit_tree_refs *p, int count)
+{
+#ifdef CONFIG_AUDIT_TREE
+ struct audit_tree_refs *q;
+ int n;
+ if (!p) {
+ /* we started with empty chain */
+ p = ctx->first_trees;
+ count = 31;
+ /* if the very first allocation has failed, nothing to do */
+ if (!p)
+ return;
+ }
+ n = count;
+ for (q = p; q != ctx->trees; q = q->next, n = 31) {
+ while (n--) {
+ audit_put_chunk(q->c[n]);
+ q->c[n] = NULL;
+ }
+ }
+ while (n-- > ctx->tree_count) {
+ audit_put_chunk(q->c[n]);
+ q->c[n] = NULL;
+ }
+ ctx->trees = p;
+ ctx->tree_count = count;
+#endif
+}
+
+static void free_tree_refs(struct audit_context *ctx)
+{
+ struct audit_tree_refs *p, *q;
+ for (p = ctx->first_trees; p; p = q) {
+ q = p->next;
+ kfree(p);
+ }
+}
+
+static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
+{
+#ifdef CONFIG_AUDIT_TREE
+ struct audit_tree_refs *p;
+ int n;
+ if (!tree)
+ return 0;
+ /* full ones */
+ for (p = ctx->first_trees; p != ctx->trees; p = p->next) {
+ for (n = 0; n < 31; n++)
+ if (audit_tree_match(p->c[n], tree))
+ return 1;
+ }
+ /* partial */
+ if (p) {
+ for (n = ctx->tree_count; n < 31; n++)
+ if (audit_tree_match(p->c[n], tree))
+ return 1;
+ }
+#endif
+ return 0;
+}
+
/* Determine if any context name data matches a rule's watch data */
/* Compare a task_struct with an audit_rule. Return 1 on match, 0
* otherwise. */
result = (name->dev == rule->watch->dev &&
name->ino == rule->watch->ino);
break;
+ case AUDIT_DIR:
+ if (ctx)
+ result = match_tree_refs(ctx, rule->tree);
+ break;
case AUDIT_LOGINUID:
result = 0;
if (ctx)
context->name_count, count);
}
audit_free_names(context);
+ unroll_tree_refs(context, NULL, 0);
+ free_tree_refs(context);
audit_free_aux(context);
kfree(context->filterkey);
kfree(context);
tsk->audit_context = new_context;
} else {
audit_free_names(context);
+ unroll_tree_refs(context, NULL, 0);
audit_free_aux(context);
context->aux = NULL;
context->aux_pids = NULL;
}
}
+static inline void handle_one(const struct inode *inode)
+{
+#ifdef CONFIG_AUDIT_TREE
+ struct audit_context *context;
+ struct audit_tree_refs *p;
+ struct audit_chunk *chunk;
+ int count;
+ if (likely(list_empty(&inode->inotify_watches)))
+ return;
+ context = current->audit_context;
+ p = context->trees;
+ count = context->tree_count;
+ rcu_read_lock();
+ chunk = audit_tree_lookup(inode);
+ rcu_read_unlock();
+ if (!chunk)
+ return;
+ if (likely(put_tree_ref(context, chunk)))
+ return;
+ if (unlikely(!grow_tree_refs(context))) {
+ printk(KERN_WARNING "out of memory, audit has lost a tree reference");
+ audit_set_auditable(context);
+ audit_put_chunk(chunk);
+ unroll_tree_refs(context, p, count);
+ return;
+ }
+ put_tree_ref(context, chunk);
+#endif
+}
+
+static void handle_path(const struct dentry *dentry)
+{
+#ifdef CONFIG_AUDIT_TREE
+ struct audit_context *context;
+ struct audit_tree_refs *p;
+ const struct dentry *d, *parent;
+ struct audit_chunk *drop;
+ unsigned long seq;
+ int count;
+
+ context = current->audit_context;
+ p = context->trees;
+ count = context->tree_count;
+retry:
+ drop = NULL;
+ d = dentry;
+ rcu_read_lock();
+ seq = read_seqbegin(&rename_lock);
+ for(;;) {
+ struct inode *inode = d->d_inode;
+ if (inode && unlikely(!list_empty(&inode->inotify_watches))) {
+ struct audit_chunk *chunk;
+ chunk = audit_tree_lookup(inode);
+ if (chunk) {
+ if (unlikely(!put_tree_ref(context, chunk))) {
+ drop = chunk;
+ break;
+ }
+ }
+ }
+ parent = d->d_parent;
+ if (parent == d)
+ break;
+ d = parent;
+ }
+ if (unlikely(read_seqretry(&rename_lock, seq) || drop)) { /* in this order */
+ rcu_read_unlock();
+ if (!drop) {
+ /* just a race with rename */
+ unroll_tree_refs(context, p, count);
+ goto retry;
+ }
+ audit_put_chunk(drop);
+ if (grow_tree_refs(context)) {
+ /* OK, got more space */
+ unroll_tree_refs(context, p, count);
+ goto retry;
+ }
+ /* too bad */
+ printk(KERN_WARNING
+ "out of memory, audit has lost a tree reference");
+ unroll_tree_refs(context, p, count);
+ audit_set_auditable(context);
+ return;
+ }
+ rcu_read_unlock();
+#endif
+}
+
/**
* audit_getname - add a name to the list
* @name: name to add
{
int idx;
struct audit_context *context = current->audit_context;
- const struct inode *inode = inode = dentry->d_inode;
+ const struct inode *inode = dentry->d_inode;
if (!context->in_syscall)
return;
idx = context->name_count - 1;
context->names[idx].name = NULL;
}
+ handle_path(dentry);
audit_copy_inode(&context->names[idx], inode);
}
if (!context->in_syscall)
return;
+ if (inode)
+ handle_one(inode);
/* determine matching parent */
if (!dname)
goto add_names;
projects / openwrt / staging / blogic.git / commitdiff