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| author | Daniel Rosenberg <drosen@google.com> | 2020-01-20 23:31:56 +0100 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2020-01-22 23:47:15 +0100 |
| commit | 6e1918cfb263acacd3fc9239127732b69de64695 (patch) | |
| tree | f568fcd5fbed7df8ff441c664f18be933593ebd7 /Documentation/filesystems/fscrypt.rst | |
| parent | fscrypt: add "fscrypt_" prefix to fname_encrypt() (diff) | |
| download | linux-6e1918cfb263acacd3fc9239127732b69de64695.tar.xz linux-6e1918cfb263acacd3fc9239127732b69de64695.zip | |
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/filesystems/fscrypt.rst')
| -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 9c53336d06a4..380a1be9550e 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 |