Re: [PATCH 1/3] audit: don't free_chunk() after fsnotify_add_mark()

From: Eric Paris
Date: Fri Jul 06 2012 - 14:13:30 EST


On Mon, 2012-06-25 at 19:46 +0200, Miklos Szeredi wrote:
> From: Miklos Szeredi <mszeredi@xxxxxxx>
>
> Don't do free_chunk() after fsnotify_add_mark(). That one does a delayed unref
> via the destroy list and this results in use-after-free.
>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
> CC: stable@xxxxxxxxxxxxxxx

Al, can you send these along? I am not going to see a computer again
for a month. Hurray!

Acked-by: Eric Paris <eparis@xxxxxxxxxx>

> ---
> kernel/audit_tree.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
> index 5bf0790..d52d247 100644
> --- a/kernel/audit_tree.c
> +++ b/kernel/audit_tree.c
> @@ -259,7 +259,7 @@ static void untag_chunk(struct node *p)
>
> fsnotify_duplicate_mark(&new->mark, entry);
> if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.i.inode, NULL, 1)) {
> - free_chunk(new);
> + fsnotify_put_mark(&new->mark);
> goto Fallback;
> }
>
> @@ -322,7 +322,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
>
> entry = &chunk->mark;
> if (fsnotify_add_mark(entry, audit_tree_group, inode, NULL, 0)) {
> - free_chunk(chunk);
> + fsnotify_put_mark(entry);
> return -ENOSPC;
> }
>
> @@ -396,7 +396,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
> 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);
> - free_chunk(chunk);
> + fsnotify_put_mark(chunk_entry);
> fsnotify_put_mark(old_entry);
> return -ENOSPC;
> }


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