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Commit f51dcd0f authored by Al Viro's avatar Al Viro
Browse files

apparmorfs: fix use-after-free on symlink traversal 



symlink body shouldn't be freed without an RCU delay.  Switch apparmorfs
to ->destroy_inode() and use of call_rcu(); free both the inode and symlink
body in the callback.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 46c87441

security/apparmor/apparmorfs.c

+9 −4
Original line number Diff line number Diff line
@@ -123,17 +123,22 @@ static int aafs_show_path(struct seq_file *seq, struct dentry *dentry) 
	return 0;

}



static void aafs_evict_inode(struct inode *inode)

static void aafs_i_callback(struct rcu_head *head)

{

	truncate_inode_pages_final(&inode->i_data);

	clear_inode(inode);

	struct inode *inode = container_of(head, struct inode, i_rcu);

	if (S_ISLNK(inode->i_mode))

		kfree(inode->i_link);

	free_inode_nonrcu(inode);

}



static void aafs_destroy_inode(struct inode *inode)

{

	call_rcu(&inode->i_rcu, aafs_i_callback);

}



static const struct super_operations aafs_super_ops = {

	.statfs = simple_statfs,

	.evict_inode = aafs_evict_inode,

	.destroy_inode = aafs_destroy_inode,

	.show_path = aafs_show_path,

};