diff options
| author | Daniel Rosenberg <drosen@google.com> | 2020-01-20 14:31:56 -0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@google.com> | 2020-02-13 15:12:08 -0800 |
| commit | e16d8494ecc69348badaaef8631040d40ef1e91d (patch) | |
| tree | e616e04c6af629e235e58c5b4fd30d75892dbe95 /Documentation | |
| parent | 0bc68c180e8e56afe74a5c9ae455165414d61373 (diff) | |
fscrypt: don't allow v1 policies with casefolding
Casefolded encrypted directories will use a new dirhash method that
requires a secret key. If the directory uses a v2 encryption policy,
it's easy to derive this key from the master key using HKDF. However,
v1 encryption policies don't provide a way to derive additional keys.
Therefore, don't allow casefolding on directories that use a v1 policy.
Specifically, make it so that trying to enable casefolding on a
directory that has a v1 policy fails, trying to set a v1 policy on a
casefolded directory fails, and trying to open a casefolded directory
that has a v1 policy (if one somehow exists on-disk) fails.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
[EB: improved commit message, updated fscrypt.rst, and other cleanups]
Link: https://lore.kernel.org/r/20200120223201.241390-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 4ed9d58ea0ab..9514bef7e99e 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -513,7 +513,9 @@ FS_IOC_SET_ENCRYPTION_POLICY can fail with the following errors: - ``EEXIST``: the file is already encrypted with an encryption policy different from the one specified - ``EINVAL``: an invalid encryption policy was specified (invalid - version, mode(s), or flags; or reserved bits were set) + version, mode(s), or flags; or reserved bits were set); or a v1 + encryption policy was specified but the directory has the casefold + flag enabled (casefolding is incompatible with v1 policies). - ``ENOKEY``: a v2 encryption policy was specified, but the key with the specified ``master_key_identifier`` has not been added, nor does the process have the CAP_FOWNER capability in the initial user |