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authorJan Kara <jack@suse.cz>2018-11-12 15:54:49 +0100
committerPaul Moore <paul@paul-moore.com>2018-11-12 15:54:49 +0100
commitc22fcde775dcc9f46d73d694061441efdc7bdaad (patch)
treeb95b570ed053de37ac4e0aaa353749e317a8bea7 /kernel/audit_tree.c
parentaudit: Guarantee forward progress of chunk untagging (diff)
downloadlinux-c22fcde775dcc9f46d73d694061441efdc7bdaad.tar.xz
linux-c22fcde775dcc9f46d73d694061441efdc7bdaad.zip
audit: Drop all unused chunk nodes during deletion
When deleting chunk from a tree, drop all unused nodes in a chunk instead of just the one used by the tree. This gets rid of possibly lingering unused nodes (created due to fallback path in untag_chunk()) and also removes some special cases and will allow us to simplify locking in untag_chunk(). Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'kernel/audit_tree.c')
-rw-r--r--kernel/audit_tree.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index ca2b6baff7aa..145e8c92dd31 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -277,8 +277,7 @@ static struct audit_chunk *find_chunk(struct node *p)
return container_of(p, struct audit_chunk, owners[0]);
}
-static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old,
- struct node *skip)
+static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old)
{
struct audit_tree *owner;
int i, j;
@@ -288,7 +287,7 @@ static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old,
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] == skip) {
+ if (!old->owners[j].owner) {
i--;
continue;
}
@@ -322,20 +321,28 @@ static void remove_chunk_node(struct audit_chunk *chunk, struct node *p)
put_tree(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 node *p)
{
struct audit_chunk *chunk = find_chunk(p);
struct fsnotify_mark *entry = chunk->mark;
struct audit_chunk *new = NULL;
- int size = chunk->count - 1;
+ int size;
remove_chunk_node(chunk, p);
fsnotify_get_mark(entry);
spin_unlock(&hash_lock);
- if (size)
- new = alloc_chunk(size);
-
mutex_lock(&entry->group->mark_mutex);
/*
* mark_mutex protects mark from getting detached and thus also from
@@ -348,6 +355,7 @@ static void untag_chunk(struct node *p)
goto out;
}
+ size = chunk_count_trees(chunk);
if (!size) {
chunk->dead = 1;
spin_lock(&hash_lock);
@@ -360,6 +368,7 @@ static void untag_chunk(struct node *p)
goto out;
}
+ new = alloc_chunk(size);
if (!new)
goto out_mutex;
@@ -375,7 +384,7 @@ static void untag_chunk(struct node *p)
* 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, p);
+ replace_chunk(new, chunk);
spin_unlock(&hash_lock);
fsnotify_detach_mark(entry);
mutex_unlock(&entry->group->mark_mutex);
@@ -520,7 +529,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
* 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, NULL);
+ replace_chunk(chunk, old);
spin_unlock(&hash_lock);
fsnotify_detach_mark(old_entry);
mutex_unlock(&audit_tree_group->mark_mutex);