diff options
Diffstat (limited to 'kernel/audit_tree.c')
| -rw-r--r-- | kernel/audit_tree.c | 738 |
1 files changed, 433 insertions, 305 deletions
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 43c307dc9453..fda6beb041e0 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -1,15 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0 #include "audit.h" #include <linux/fsnotify_backend.h> #include <linux/namei.h> #include <linux/mount.h> #include <linux/kthread.h> +#include <linux/refcount.h> #include <linux/slab.h> struct audit_tree; struct audit_chunk; struct audit_tree { - atomic_t count; + refcount_t count; int goner; struct audit_chunk *root; struct list_head chunks; @@ -22,25 +24,38 @@ struct audit_tree { struct audit_chunk { struct list_head hash; - struct fsnotify_mark mark; + unsigned long key; + struct fsnotify_mark *mark; struct list_head trees; /* with root here */ - int dead; int count; atomic_long_t refs; struct rcu_head head; - struct node { + struct audit_node { struct list_head list; struct audit_tree *owner; unsigned index; /* index; upper bit indicates 'will prune' */ - } owners[]; + } owners[] __counted_by(count); +}; + +struct audit_tree_mark { + struct fsnotify_mark mark; + struct audit_chunk *chunk; }; static LIST_HEAD(tree_list); static LIST_HEAD(prune_list); +static struct task_struct *prune_thread; /* - * One struct chunk is attached to each inode of interest. - * We replace struct chunk on tagging/untagging. + * One struct chunk is attached to each inode of interest through + * audit_tree_mark (fsnotify mark). We replace struct chunk on tagging / + * untagging, the mark is stable as long as there is chunk attached. The + * association between mark and chunk is protected by hash_lock and + * audit_tree_group->mark_mutex. Thus as long as we hold + * audit_tree_group->mark_mutex and check that the mark is alive by + * FSNOTIFY_MARK_FLAG_ATTACHED flag check, we are sure the mark points to + * the current chunk. + * * Rules have pointer to struct audit_tree. * Rules have struct list_head rlist forming a list of rules over * the same tree. @@ -59,8 +74,12 @@ static LIST_HEAD(prune_list); * 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 fsnotify_mark + .refs (non-zero refcount - * of watch contributes 1 to .refs). + * chunk is refcounted by embedded .refs. Mark associated with the chunk holds + * one chunk reference. This reference is dropped either when a mark is going + * to be freed (corresponding inode goes away) or when chunk attached to the + * mark gets replaced. This reference must be dropped using + * audit_mark_put_chunk() to make sure the reference is dropped only after RCU + * grace period as it protects RCU readers of the hash table. * * 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 @@ -68,34 +87,37 @@ static LIST_HEAD(prune_list); * that makes a difference. Some. */ -static struct fsnotify_group *audit_tree_group; +static struct fsnotify_group *audit_tree_group __ro_after_init; +static struct kmem_cache *audit_tree_mark_cachep __ro_after_init; static struct audit_tree *alloc_tree(const char *s) { struct audit_tree *tree; + size_t sz; - tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL); + sz = strlen(s) + 1; + tree = kmalloc(struct_size(tree, pathname, sz), GFP_KERNEL); if (tree) { - atomic_set(&tree->count, 1); + refcount_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); + strscpy(tree->pathname, s, sz); } return tree; } static inline void get_tree(struct audit_tree *tree) { - atomic_inc(&tree->count); + refcount_inc(&tree->count); } static inline void put_tree(struct audit_tree *tree) { - if (atomic_dec_and_test(&tree->count)) + if (refcount_dec_and_test(&tree->count)) kfree_rcu(tree, head); } @@ -128,20 +150,49 @@ static void __put_chunk(struct rcu_head *rcu) audit_put_chunk(chunk); } -static void audit_tree_destroy_watch(struct fsnotify_mark *entry) +/* + * Drop reference to the chunk that was held by the mark. This is the reference + * that gets dropped after we've removed the chunk from the hash table and we + * use it to make sure chunk cannot be freed before RCU grace period expires. + */ +static void audit_mark_put_chunk(struct audit_chunk *chunk) { - struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); call_rcu(&chunk->head, __put_chunk); } +static inline struct audit_tree_mark *audit_mark(struct fsnotify_mark *mark) +{ + return container_of(mark, struct audit_tree_mark, mark); +} + +static struct audit_chunk *mark_chunk(struct fsnotify_mark *mark) +{ + return audit_mark(mark)->chunk; +} + +static void audit_tree_destroy_watch(struct fsnotify_mark *mark) +{ + kmem_cache_free(audit_tree_mark_cachep, audit_mark(mark)); +} + +static struct fsnotify_mark *alloc_mark(void) +{ + struct audit_tree_mark *amark; + + amark = kmem_cache_zalloc(audit_tree_mark_cachep, GFP_KERNEL); + if (!amark) + return NULL; + fsnotify_init_mark(&amark->mark, audit_tree_group); + amark->mark.mask = FS_IN_IGNORED; + return &amark->mark; +} + 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); + chunk = kzalloc(struct_size(chunk, owners, count), GFP_KERNEL); if (!chunk) return NULL; @@ -153,7 +204,6 @@ static struct audit_chunk *alloc_chunk(int count) INIT_LIST_HEAD(&chunk->owners[i].list); chunk->owners[i].index = i; } - fsnotify_init_mark(&chunk->mark, audit_tree_destroy_watch); return chunk; } @@ -161,33 +211,48 @@ 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) +/* Function to return search key in our hash from inode. */ +static unsigned long inode_to_key(const struct inode *inode) +{ + /* Use address pointed to by connector->obj as the key */ + return (unsigned long)&inode->i_fsnotify_marks; +} + +static inline struct list_head *chunk_hash(unsigned long key) { - unsigned long n = (unsigned long)inode / L1_CACHE_BYTES; + unsigned long n = key / L1_CACHE_BYTES; return chunk_hash_heads + n % HASH_SIZE; } -/* hash_lock & entry->lock is held by caller */ +/* hash_lock & mark->group->mark_mutex is held by caller */ static void insert_hash(struct audit_chunk *chunk) { - struct fsnotify_mark *entry = &chunk->mark; struct list_head *list; - if (!entry->i.inode) - return; - list = chunk_hash(entry->i.inode); + /* + * Make sure chunk is fully initialized before making it visible in the + * hash. Pairs with a data dependency barrier in READ_ONCE() in + * audit_tree_lookup(). + */ + smp_wmb(); + WARN_ON_ONCE(!chunk->key); + list = chunk_hash(chunk->key); 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); + unsigned long key = inode_to_key(inode); + struct list_head *list = chunk_hash(key); struct audit_chunk *p; list_for_each_entry_rcu(p, list, hash) { - /* mark.inode may have gone NULL, but who cares? */ - if (p->mark.i.inode == inode) { + /* + * We use a data dependency barrier in READ_ONCE() to make sure + * the chunk we see is fully initialized. + */ + if (READ_ONCE(p->key) == key) { atomic_long_inc(&p->refs); return p; } @@ -195,146 +260,177 @@ struct audit_chunk *audit_tree_lookup(const struct inode *inode) return NULL; } -int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree) +bool 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; + return true; + return false; } /* tagging and untagging inodes with trees */ -static struct audit_chunk *find_chunk(struct node *p) +static struct audit_chunk *find_chunk(struct audit_node *p) { int index = p->index & ~(1U<<31); p -= index; return container_of(p, struct audit_chunk, owners[0]); } -static void untag_chunk(struct node *p) +static void replace_mark_chunk(struct fsnotify_mark *mark, + struct audit_chunk *chunk) +{ + struct audit_chunk *old; + + assert_spin_locked(&hash_lock); + old = mark_chunk(mark); + audit_mark(mark)->chunk = chunk; + if (chunk) + chunk->mark = mark; + if (old) + old->mark = NULL; +} + +static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old) { - struct audit_chunk *chunk = find_chunk(p); - struct fsnotify_mark *entry = &chunk->mark; - struct audit_chunk *new = NULL; struct audit_tree *owner; - int size = chunk->count - 1; int i, j; - fsnotify_get_mark(entry); - - spin_unlock(&hash_lock); + new->key = old->key; + list_splice_init(&old->trees, &new->trees); + list_for_each_entry(owner, &new->trees, same_root) + owner->root = new; + for (i = j = 0; j < old->count; i++, j++) { + if (!old->owners[j].owner) { + i--; + continue; + } + owner = old->owners[j].owner; + new->owners[i].owner = owner; + new->owners[i].index = old->owners[j].index - j + i; + if (!owner) /* result of earlier fallback */ + continue; + get_tree(owner); + list_replace_init(&old->owners[j].list, &new->owners[i].list); + } + replace_mark_chunk(old->mark, new); + /* + * Make sure chunk is fully initialized before making it visible in the + * hash. Pairs with a data dependency barrier in READ_ONCE() in + * audit_tree_lookup(). + */ + smp_wmb(); + list_replace_rcu(&old->hash, &new->hash); +} - if (size) - new = alloc_chunk(size); +static void remove_chunk_node(struct audit_chunk *chunk, struct audit_node *p) +{ + struct audit_tree *owner = p->owner; - spin_lock(&entry->lock); - if (chunk->dead || !entry->i.inode) { - spin_unlock(&entry->lock); - if (new) - free_chunk(new); - goto out; + if (owner->root == chunk) { + list_del_init(&owner->same_root); + owner->root = NULL; } + list_del_init(&p->list); + p->owner = NULL; + put_tree(owner); +} - owner = p->owner; +static int chunk_count_trees(struct audit_chunk *chunk) +{ + int i; + int ret = 0; + for (i = 0; i < chunk->count; i++) + if (chunk->owners[i].owner) + ret++; + return ret; +} + +static void untag_chunk(struct audit_chunk *chunk, struct fsnotify_mark *mark) +{ + struct audit_chunk *new; + int size; + + fsnotify_group_lock(audit_tree_group); + /* + * mark_mutex stabilizes chunk attached to the mark so we can check + * whether it didn't change while we've dropped hash_lock. + */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) || + mark_chunk(mark) != chunk) + goto out_mutex; + + size = chunk_count_trees(chunk); 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); + replace_mark_chunk(mark, NULL); spin_unlock(&hash_lock); - spin_unlock(&entry->lock); - fsnotify_destroy_mark(entry, audit_tree_group); - goto out; + fsnotify_detach_mark(mark); + fsnotify_group_unlock(audit_tree_group); + audit_mark_put_chunk(chunk); + fsnotify_free_mark(mark); + return; } + new = alloc_chunk(size); if (!new) - goto Fallback; - - fsnotify_duplicate_mark(&new->mark, entry); - if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.i.inode, NULL, 1)) { - fsnotify_put_mark(&new->mark); - goto Fallback; - } + goto out_mutex; - 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; j <= 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[j].list, &new->owners[i].list); - } - - list_replace_rcu(&chunk->hash, &new->hash); - list_for_each_entry(owner, &new->trees, same_root) - owner->root = new; + /* + * This has to go last when updating chunk as once replace_chunk() is + * called, new RCU readers can see the new chunk. + */ + replace_chunk(new, chunk); spin_unlock(&hash_lock); - spin_unlock(&entry->lock); - fsnotify_destroy_mark(entry, audit_tree_group); - fsnotify_put_mark(&new->mark); /* drop initial reference */ - goto out; + fsnotify_group_unlock(audit_tree_group); + audit_mark_put_chunk(chunk); + 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); - spin_unlock(&entry->lock); -out: - fsnotify_put_mark(entry); - spin_lock(&hash_lock); +out_mutex: + fsnotify_group_unlock(audit_tree_group); } +/* Call with group->mark_mutex held, releases it */ static int create_chunk(struct inode *inode, struct audit_tree *tree) { - struct fsnotify_mark *entry; + struct fsnotify_mark *mark; struct audit_chunk *chunk = alloc_chunk(1); - if (!chunk) + + if (!chunk) { + fsnotify_group_unlock(audit_tree_group); return -ENOMEM; + } - entry = &chunk->mark; - if (fsnotify_add_mark(entry, audit_tree_group, inode, NULL, 0)) { - fsnotify_put_mark(entry); + mark = alloc_mark(); + if (!mark) { + fsnotify_group_unlock(audit_tree_group); + kfree(chunk); + return -ENOMEM; + } + + if (fsnotify_add_inode_mark_locked(mark, inode, 0)) { + fsnotify_group_unlock(audit_tree_group); + fsnotify_put_mark(mark); + kfree(chunk); return -ENOSPC; } - spin_lock(&entry->lock); spin_lock(&hash_lock); if (tree->goner) { spin_unlock(&hash_lock); - chunk->dead = 1; - spin_unlock(&entry->lock); - fsnotify_destroy_mark(entry, audit_tree_group); - fsnotify_put_mark(entry); + fsnotify_detach_mark(mark); + fsnotify_group_unlock(audit_tree_group); + fsnotify_free_mark(mark); + fsnotify_put_mark(mark); + kfree(chunk); return 0; } + replace_mark_chunk(mark, chunk); chunk->owners[0].index = (1U << 31); chunk->owners[0].owner = tree; get_tree(tree); @@ -343,34 +439,49 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) tree->root = chunk; list_add(&tree->same_root, &chunk->trees); } + chunk->key = inode_to_key(inode); + /* + * Inserting into the hash table has to go last as once we do that RCU + * readers can see the chunk. + */ insert_hash(chunk); spin_unlock(&hash_lock); - spin_unlock(&entry->lock); - fsnotify_put_mark(entry); /* drop initial reference */ + fsnotify_group_unlock(audit_tree_group); + /* + * Drop our initial reference. When mark we point to is getting freed, + * we get notification through ->freeing_mark callback and cleanup + * chunk pointing to this mark. + */ + fsnotify_put_mark(mark); return 0; } /* the first tagged inode becomes root of tree */ static int tag_chunk(struct inode *inode, struct audit_tree *tree) { - struct fsnotify_mark *old_entry, *chunk_entry; - struct audit_tree *owner; + struct fsnotify_mark *mark; struct audit_chunk *chunk, *old; - struct node *p; + struct audit_node *p; int n; - old_entry = fsnotify_find_inode_mark(audit_tree_group, inode); - if (!old_entry) + fsnotify_group_lock(audit_tree_group); + mark = fsnotify_find_inode_mark(inode, audit_tree_group); + if (!mark) return create_chunk(inode, tree); - old = container_of(old_entry, struct audit_chunk, mark); - + /* + * Found mark is guaranteed to be attached and mark_mutex protects mark + * from getting detached and thus it makes sure there is chunk attached + * to the mark. + */ /* are we already there? */ spin_lock(&hash_lock); + old = mark_chunk(mark); for (n = 0; n < old->count; n++) { if (old->owners[n].owner == tree) { spin_unlock(&hash_lock); - fsnotify_put_mark(old_entry); + fsnotify_group_unlock(audit_tree_group); + fsnotify_put_mark(mark); return 0; } } @@ -378,94 +489,59 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) chunk = alloc_chunk(old->count + 1); if (!chunk) { - fsnotify_put_mark(old_entry); + fsnotify_group_unlock(audit_tree_group); + fsnotify_put_mark(mark); return -ENOMEM; } - chunk_entry = &chunk->mark; - - spin_lock(&old_entry->lock); - if (!old_entry->i.inode) { - /* old_entry is being shot, lets just lie */ - spin_unlock(&old_entry->lock); - fsnotify_put_mark(old_entry); - free_chunk(chunk); - return -ENOENT; - } - - fsnotify_duplicate_mark(chunk_entry, old_entry); - if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->i.inode, NULL, 1)) { - spin_unlock(&old_entry->lock); - fsnotify_put_mark(chunk_entry); - fsnotify_put_mark(old_entry); - return -ENOSPC; - } - - /* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */ - spin_lock(&chunk_entry->lock); spin_lock(&hash_lock); - - /* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */ if (tree->goner) { spin_unlock(&hash_lock); - chunk->dead = 1; - spin_unlock(&chunk_entry->lock); - spin_unlock(&old_entry->lock); - - fsnotify_destroy_mark(chunk_entry, audit_tree_group); - - fsnotify_put_mark(chunk_entry); - fsnotify_put_mark(old_entry); + fsnotify_group_unlock(audit_tree_group); + fsnotify_put_mark(mark); + kfree(chunk); 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 = &chunk->owners[chunk->count - 1]; 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); } + /* + * This has to go last when updating chunk as once replace_chunk() is + * called, new RCU readers can see the new chunk. + */ + replace_chunk(chunk, old); spin_unlock(&hash_lock); - spin_unlock(&chunk_entry->lock); - spin_unlock(&old_entry->lock); - fsnotify_destroy_mark(old_entry, audit_tree_group); - fsnotify_put_mark(chunk_entry); /* drop initial reference */ - fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */ + fsnotify_group_unlock(audit_tree_group); + fsnotify_put_mark(mark); /* pair to fsnotify_find_mark */ + audit_mark_put_chunk(old); + return 0; } -static void audit_log_remove_rule(struct audit_krule *rule) +static void audit_tree_log_remove_rule(struct audit_context *context, + struct audit_krule *rule) { struct audit_buffer *ab; - ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); + if (!audit_enabled) + return; + ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (unlikely(!ab)) return; - audit_log_format(ab, "op="); - audit_log_string(ab, "remove rule"); - audit_log_format(ab, " dir="); + audit_log_format(ab, "op=remove_rule dir="); audit_log_untrustedstring(ab, rule->tree->pathname); audit_log_key(ab, rule->filterkey); audit_log_format(ab, " list=%d res=1", rule->listnr); audit_log_end(ab); } -static void kill_rules(struct audit_tree *tree) +static void kill_rules(struct audit_context *context, struct audit_tree *tree) { struct audit_krule *rule, *next; struct audit_entry *entry; @@ -476,7 +552,9 @@ static void kill_rules(struct audit_tree *tree) list_del_init(&rule->rlist); if (rule->tree) { /* not a half-baked one */ - audit_log_remove_rule(rule); + audit_tree_log_remove_rule(context, rule); + if (entry->rule.exe) + audit_remove_mark(entry->rule.exe); rule->tree = NULL; list_del_rcu(&entry->list); list_del(&entry->rule.list); @@ -486,19 +564,45 @@ static void kill_rules(struct audit_tree *tree) } /* - * finish killing struct audit_tree + * Remove tree from chunks. If 'tagged' is set, remove tree only from tagged + * chunks. The function expects tagged chunks are all at the beginning of the + * chunks list. */ -static void prune_one(struct audit_tree *victim) +static void prune_tree_chunks(struct audit_tree *victim, bool tagged) { spin_lock(&hash_lock); while (!list_empty(&victim->chunks)) { - struct node *p; + struct audit_node *p; + struct audit_chunk *chunk; + struct fsnotify_mark *mark; - p = list_entry(victim->chunks.next, struct node, list); + p = list_first_entry(&victim->chunks, struct audit_node, list); + /* have we run out of marked? */ + if (tagged && !(p->index & (1U<<31))) + break; + chunk = find_chunk(p); + mark = chunk->mark; + remove_chunk_node(chunk, p); + /* Racing with audit_tree_freeing_mark()? */ + if (!mark) + continue; + fsnotify_get_mark(mark); + spin_unlock(&hash_lock); + + untag_chunk(chunk, mark); + fsnotify_put_mark(mark); - untag_chunk(p); + spin_lock(&hash_lock); } spin_unlock(&hash_lock); +} + +/* + * finish killing struct audit_tree + */ +static void prune_one(struct audit_tree *victim) +{ + prune_tree_chunks(victim, false); put_tree(victim); } @@ -514,30 +618,23 @@ static void trim_marked(struct audit_tree *tree) } /* reorder */ for (p = tree->chunks.next; p != &tree->chunks; p = q) { - struct node *node = list_entry(p, struct node, list); + struct audit_node *node = list_entry(p, struct audit_node, list); q = p->next; if (node->index & (1U<<31)) { list_del_init(p); list_add(p, &tree->chunks); } } + spin_unlock(&hash_lock); - while (!list_empty(&tree->chunks)) { - struct node *node; - - node = list_entry(tree->chunks.next, struct node, list); + prune_tree_chunks(tree, true); - /* have we run out of marked? */ - if (!(node->index & (1U<<31))) - break; - - untag_chunk(node); - } + spin_lock(&hash_lock); if (!tree->root && !tree->goner) { tree->goner = 1; spin_unlock(&hash_lock); mutex_lock(&audit_filter_mutex); - kill_rules(tree); + kill_rules(audit_context(), tree); list_del_init(&tree->list); mutex_unlock(&audit_filter_mutex); prune_one(tree); @@ -573,11 +670,6 @@ int audit_remove_tree_rule(struct audit_krule *rule) return 0; } -static int compare_root(struct vfsmount *mnt, void *arg) -{ - return mnt->mnt_root->d_inode == arg; -} - void audit_trim_trees(void) { struct list_head cursor; @@ -587,37 +679,41 @@ void audit_trim_trees(void) while (cursor.next != &tree_list) { struct audit_tree *tree; struct path path; - struct vfsmount *root_mnt; - struct node *node; + struct audit_node *node; + const struct path *paths; + struct path array[16]; int err; tree = container_of(cursor.next, struct audit_tree, list); get_tree(tree); - list_del(&cursor); - list_add(&cursor, &tree->list); + list_move(&cursor, &tree->list); mutex_unlock(&audit_filter_mutex); err = kern_path(tree->pathname, 0, &path); if (err) goto skip_it; - root_mnt = collect_mounts(&path); + paths = collect_paths(&path, array, 16); path_put(&path); - if (IS_ERR(root_mnt)) + if (IS_ERR(paths)) goto skip_it; spin_lock(&hash_lock); list_for_each_entry(node, &tree->chunks, list) { struct audit_chunk *chunk = find_chunk(node); /* this could be NULL if the watch is dying else where... */ - struct inode *inode = chunk->mark.i.inode; node->index |= 1U<<31; - if (iterate_mounts(compare_root, inode, root_mnt)) - node->index &= ~(1U<<31); + for (const struct path *p = paths; p->dentry; p++) { + struct inode *inode = p->dentry->d_inode; + if (inode_to_key(inode) == chunk->key) { + node->index &= ~(1U<<31); + break; + } + } } spin_unlock(&hash_lock); trim_marked(tree); - drop_collected_mounts(root_mnt); + drop_collected_paths(paths, array); skip_it: put_tree(tree); mutex_lock(&audit_filter_mutex); @@ -630,7 +726,8 @@ int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op) { if (pathname[0] != '/' || - rule->listnr != AUDIT_FILTER_EXIT || + (rule->listnr != AUDIT_FILTER_EXIT && + rule->listnr != AUDIT_FILTER_URING_EXIT) || op != Audit_equal || rule->inode_f || rule->watch || rule->tree) return -EINVAL; @@ -645,9 +742,63 @@ void audit_put_tree(struct audit_tree *tree) put_tree(tree); } -static int tag_mount(struct vfsmount *mnt, void *arg) +static int tag_mounts(const struct path *paths, struct audit_tree *tree) { - return tag_chunk(mnt->mnt_root->d_inode, arg); + for (const struct path *p = paths; p->dentry; p++) { + int err = tag_chunk(p->dentry->d_inode, tree); + if (err) + return err; + } + return 0; +} + +/* + * That gets run when evict_chunk() ends up needing to kill audit_tree. + * Runs from a separate thread. + */ +static int prune_tree_thread(void *unused) +{ + for (;;) { + if (list_empty(&prune_list)) { + set_current_state(TASK_INTERRUPTIBLE); + schedule(); + } + + audit_ctl_lock(); + 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); + audit_ctl_unlock(); + } + return 0; +} + +static int audit_launch_prune(void) +{ + if (prune_thread) + return 0; + prune_thread = kthread_run(prune_tree_thread, NULL, + "audit_prune_tree"); + if (IS_ERR(prune_thread)) { + pr_err("cannot start thread audit_prune_tree"); + prune_thread = NULL; + return -ENOMEM; + } + return 0; } /* called with audit_filter_mutex */ @@ -655,7 +806,8 @@ int audit_add_tree_rule(struct audit_krule *rule) { struct audit_tree *seed = rule->tree, *tree; struct path path; - struct vfsmount *mnt; + struct path array[16]; + const struct path *paths; int err; rule->tree = NULL; @@ -673,22 +825,28 @@ int audit_add_tree_rule(struct audit_krule *rule) /* do not set rule->tree yet */ mutex_unlock(&audit_filter_mutex); + if (unlikely(!prune_thread)) { + err = audit_launch_prune(); + if (err) + goto Err; + } + err = kern_path(tree->pathname, 0, &path); if (err) goto Err; - mnt = collect_mounts(&path); + paths = collect_paths(&path, array, 16); path_put(&path); - if (IS_ERR(mnt)) { - err = PTR_ERR(mnt); + if (IS_ERR(paths)) { + err = PTR_ERR(paths); goto Err; } get_tree(tree); - err = iterate_mounts(tag_mount, tree, mnt); - drop_collected_mounts(mnt); + err = tag_mounts(paths, tree); + drop_collected_paths(paths, array); if (!err) { - struct node *node; + struct audit_node *node; spin_lock(&hash_lock); list_for_each_entry(node, &tree->chunks, list) node->index &= ~(1U<<31); @@ -720,20 +878,21 @@ int audit_tag_tree(char *old, char *new) struct list_head cursor, barrier; int failed = 0; struct path path1, path2; - struct vfsmount *tagged; + struct path array[16]; + const struct path *paths; int err; err = kern_path(new, 0, &path2); if (err) return err; - tagged = collect_mounts(&path2); + paths = collect_paths(&path2, array, 16); path_put(&path2); - if (IS_ERR(tagged)) - return PTR_ERR(tagged); + if (IS_ERR(paths)) + return PTR_ERR(paths); err = kern_path(old, 0, &path1); if (err) { - drop_collected_mounts(tagged); + drop_collected_paths(paths, array); return err; } @@ -747,8 +906,7 @@ int audit_tag_tree(char *old, char *new) tree = container_of(cursor.next, struct audit_tree, list); get_tree(tree); - list_del(&cursor); - list_add(&cursor, &tree->list); + list_move(&cursor, &tree->list); mutex_unlock(&audit_filter_mutex); err = kern_path(tree->pathname, 0, &path2); @@ -763,7 +921,7 @@ int audit_tag_tree(char *old, char *new) continue; } - failed = iterate_mounts(tag_mount, tree, tagged); + failed = tag_mounts(paths, tree); if (failed) { put_tree(tree); mutex_lock(&audit_filter_mutex); @@ -773,8 +931,7 @@ int audit_tag_tree(char *old, char *new) mutex_lock(&audit_filter_mutex); spin_lock(&hash_lock); if (!tree->goner) { - list_del(&tree->list); - list_add(&tree->list, &tree_list); + list_move(&tree->list, &tree_list); } spin_unlock(&hash_lock); put_tree(tree); @@ -785,12 +942,11 @@ int audit_tag_tree(char *old, char *new) tree = container_of(barrier.prev, struct audit_tree, list); get_tree(tree); - list_del(&tree->list); - list_add(&tree->list, &barrier); + list_move(&tree->list, &barrier); mutex_unlock(&audit_filter_mutex); if (!failed) { - struct node *node; + struct audit_node *node; spin_lock(&hash_lock); list_for_each_entry(node, &tree->chunks, list) node->index &= ~(1U<<31); @@ -806,56 +962,32 @@ int audit_tag_tree(char *old, char *new) list_del(&cursor); mutex_unlock(&audit_filter_mutex); path_put(&path1); - drop_collected_mounts(tagged); + drop_collected_paths(paths, array); return failed; } -/* - * That gets run when evict_chunk() ends up needing to kill audit_tree. - * Runs from a separate thread. - */ -static int prune_tree_thread(void *unused) -{ - mutex_lock(&audit_cmd_mutex); - 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); - mutex_unlock(&audit_cmd_mutex); - return 0; -} static void audit_schedule_prune(void) { - kthread_run(prune_tree_thread, NULL, "audit_prune_tree"); + wake_up_process(prune_thread); } /* * ... and that one is done if evict_chunk() decides to delay until the end * of syscall. Runs synchronously. */ -void audit_kill_trees(struct list_head *list) +void audit_kill_trees(struct audit_context *context) { - mutex_lock(&audit_cmd_mutex); + struct list_head *list = &context->killed_trees; + + audit_ctl_lock(); mutex_lock(&audit_filter_mutex); while (!list_empty(list)) { struct audit_tree *victim; victim = list_entry(list->next, struct audit_tree, list); - kill_rules(victim); + kill_rules(context, victim); list_del_init(&victim->list); mutex_unlock(&audit_filter_mutex); @@ -866,7 +998,7 @@ void audit_kill_trees(struct list_head *list) } mutex_unlock(&audit_filter_mutex); - mutex_unlock(&audit_cmd_mutex); + audit_ctl_unlock(); } /* @@ -880,10 +1012,6 @@ static void evict_chunk(struct audit_chunk *chunk) int need_prune = 0; int n; - if (chunk->dead) - return; - - chunk->dead = 1; mutex_lock(&audit_filter_mutex); spin_lock(&hash_lock); while (!list_empty(&chunk->trees)) { @@ -894,7 +1022,7 @@ static void evict_chunk(struct audit_chunk *chunk) list_del_init(&owner->same_root); spin_unlock(&hash_lock); if (!postponed) { - kill_rules(owner); + kill_rules(audit_context(), owner); list_move(&owner->list, &prune_list); need_prune = 1; } else { @@ -906,54 +1034,54 @@ static void evict_chunk(struct audit_chunk *chunk) for (n = 0; n < chunk->count; n++) list_del_init(&chunk->owners[n].list); spin_unlock(&hash_lock); + mutex_unlock(&audit_filter_mutex); if (need_prune) audit_schedule_prune(); - mutex_unlock(&audit_filter_mutex); } -static int audit_tree_handle_event(struct fsnotify_group *group, - struct fsnotify_mark *inode_mark, - struct fsnotify_mark *vfsmonut_mark, - struct fsnotify_event *event) +static int audit_tree_handle_event(struct fsnotify_mark *mark, u32 mask, + struct inode *inode, struct inode *dir, + const struct qstr *file_name, u32 cookie) { - BUG(); - return -EOPNOTSUPP; + return 0; } -static void audit_tree_freeing_mark(struct fsnotify_mark *entry, struct fsnotify_group *group) +static void audit_tree_freeing_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group) { - struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); + struct audit_chunk *chunk; - evict_chunk(chunk); + fsnotify_group_lock(mark->group); + spin_lock(&hash_lock); + chunk = mark_chunk(mark); + replace_mark_chunk(mark, NULL); + spin_unlock(&hash_lock); + fsnotify_group_unlock(mark->group); + if (chunk) { + evict_chunk(chunk); + audit_mark_put_chunk(chunk); + } /* * We are guaranteed to have at least one reference to the mark from * either the inode or the caller of fsnotify_destroy_mark(). */ - BUG_ON(atomic_read(&entry->refcnt) < 1); -} - -static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode, - struct fsnotify_mark *inode_mark, - struct fsnotify_mark *vfsmount_mark, - __u32 mask, void *data, int data_type) -{ - return false; + BUG_ON(refcount_read(&mark->refcnt) < 1); } static const struct fsnotify_ops audit_tree_ops = { - .handle_event = audit_tree_handle_event, - .should_send_event = audit_tree_send_event, - .free_group_priv = NULL, - .free_event_priv = NULL, + .handle_inode_event = audit_tree_handle_event, .freeing_mark = audit_tree_freeing_mark, + .free_mark = audit_tree_destroy_watch, }; static int __init audit_tree_init(void) { int i; - audit_tree_group = fsnotify_alloc_group(&audit_tree_ops); + audit_tree_mark_cachep = KMEM_CACHE(audit_tree_mark, SLAB_PANIC); + + audit_tree_group = fsnotify_alloc_group(&audit_tree_ops, 0); if (IS_ERR(audit_tree_group)) audit_panic("cannot initialize fsnotify group for rectree watches"); |