diff options
author | Daniel Rosenberg <drosen@google.com> | 2020-11-19 06:09:04 +0000 |
---|---|---|
committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2020-12-02 22:00:21 -0800 |
commit | 7ad08a58bf67594057362e45cbddd3e27e53e557 (patch) | |
tree | cc8f281ee95421efe8cb34564938b466141ee506 /fs/f2fs/hash.c | |
parent | bb9cd9106b22b4fc5ff8d78a752be8a4ba2cbba5 (diff) |
f2fs: Handle casefolding with Encryption
Expand f2fs's casefolding support to include encrypted directories. To
index casefolded+encrypted directories, we use the SipHash of the
casefolded name, keyed by a key derived from the directory's fscrypt
master key. This ensures that the dirhash doesn't leak information
about the plaintext filenames.
Encryption keys are unavailable during roll-forward recovery, so we
can't compute the dirhash when recovering a new dentry in an encrypted +
casefolded directory. To avoid having to force a checkpoint when a new
file is fsync'ed, store the dirhash on-disk appended to i_name.
This patch incorporates work by Eric Biggers <ebiggers@google.com>
and Jaegeuk Kim <jaegeuk@kernel.org>.
Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/hash.c')
-rw-r--r-- | fs/f2fs/hash.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c index de841aaf3c43..e3beac546c63 100644 --- a/fs/f2fs/hash.c +++ b/fs/f2fs/hash.c @@ -111,7 +111,9 @@ void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) * If the casefolded name is provided, hash it instead of the * on-disk name. If the casefolded name is *not* provided, that * should only be because the name wasn't valid Unicode, so fall - * back to treating the name as an opaque byte sequence. + * back to treating the name as an opaque byte sequence. Note + * that to handle encrypted directories, the fallback must use + * usr_fname (plaintext) rather than disk_name (ciphertext). */ WARN_ON_ONCE(!fname->usr_fname->name); if (fname->cf_name.name) { @@ -121,6 +123,13 @@ void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) name = fname->usr_fname->name; len = fname->usr_fname->len; } + if (IS_ENCRYPTED(dir)) { + struct qstr tmp = QSTR_INIT(name, len); + + fname->hash = + cpu_to_le32(fscrypt_fname_siphash(dir, &tmp)); + return; + } } #endif fname->hash = cpu_to_le32(TEA_hash_name(name, len)); |