From 2b25de6d445faefc28629603dd754aec9f744e60 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 15 Dec 2019 19:31:39 -0800 Subject: Metadata support for v2 encryption policies Linux v5.4 and later supports v2 encryption policies. These have several advantages over v1 encryption policies: - Their encryption keys can be added/removed to/from the filesystem by non-root users, thus gaining the benefits of the filesystem keyring while also retaining support for non-root use. - They use a more standard, secure, and flexible key derivation function. Because of this, some future kernel-level fscrypt features will be implemented for v2 policies only. - They prevent a denial-of-service attack where a user could associate the wrong key with another user's encrypted files. Prepare the fscrypt tool to support v2 encryption policies by: - Adding a policy_version field to the EncryptionOptions, i.e. to the config file and to the policy metadata files. - Using the kernel-specified algorithm to compute the key descriptor for v2 policies. - Handling setting and getting v2 policies. Actually adding/removing the keys for v2 policies to/from the kernel is left for the next patch. --- actions/config.go | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'actions/config.go') diff --git a/actions/config.go b/actions/config.go index 7fdaf5b..6b019df 100644 --- a/actions/config.go +++ b/actions/config.go @@ -133,6 +133,10 @@ func getConfig() (*metadata.Config, error) { config.Options.Filenames = metadata.DefaultOptions.Filenames log.Printf("Falling back to filenames mode of %q", config.Options.Filenames) } + if config.Options.PolicyVersion == 0 { + config.Options.PolicyVersion = metadata.DefaultOptions.PolicyVersion + log.Printf("Falling back to policy version of %d", config.Options.PolicyVersion) + } if err := config.CheckValidity(); err != nil { return nil, errors.Wrap(ErrBadConfigFile, err.Error()) -- cgit v1.2.3