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| author | Eric Biggers <ebiggers@google.com> | 2022-05-14 20:59:29 +0300 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2022-05-17 21:19:23 +0300 |
| commit | b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d (patch) | |
| tree | 01e37a83ad3acc9d6115d49787eb63927056c787 /fs/f2fs/hash.c | |
| parent | c81d5bae404abc6b257667e84d39b9b50c7063d4 (diff) | |
| download | linux-b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d.tar.xz | |
f2fs: don't use casefolded comparison for "." and ".."
Tryng to rename a directory that has all following properties fails with
EINVAL and triggers the 'WARN_ON_ONCE(!fscrypt_has_encryption_key(dir))'
in f2fs_match_ci_name():
- The directory is casefolded
- The directory is encrypted
- The directory's encryption key is not yet set up
- The parent directory is *not* encrypted
The problem is incorrect handling of the lookup of ".." to get the
parent reference to update. fscrypt_setup_filename() treats ".." (and
".") specially, as it's never encrypted. It's passed through as-is, and
setting up the directory's key is not attempted. As the name isn't a
no-key name, f2fs treats it as a "normal" name and attempts a casefolded
comparison. That breaks the assumption of the WARN_ON_ONCE() in
f2fs_match_ci_name() which assumes that for encrypted directories,
casefolded comparisons only happen when the directory's key is set up.
We could just remove this WARN_ON_ONCE(). However, since casefolding is
always a no-op on "." and ".." anyway, let's instead just not casefold
these names. This results in the standard bytewise comparison.
Fixes: 7ad08a58bf67 ("f2fs: Handle casefolding with Encryption")
Cc: <stable@vger.kernel.org> # v5.11+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.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, 6 insertions, 5 deletions
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c index 3cb1e7a24740..049ce50cec9b 100644 --- a/fs/f2fs/hash.c +++ b/fs/f2fs/hash.c @@ -91,7 +91,7 @@ static u32 TEA_hash_name(const u8 *p, size_t len) /* * Compute @fname->hash. For all directories, @fname->disk_name must be set. * For casefolded directories, @fname->usr_fname must be set, and also - * @fname->cf_name if the filename is valid Unicode. + * @fname->cf_name if the filename is valid Unicode and is not "." or "..". */ void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) { @@ -110,10 +110,11 @@ 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. Note - * that to handle encrypted directories, the fallback must use - * usr_fname (plaintext) rather than disk_name (ciphertext). + * should only be because the name wasn't valid Unicode or was + * "." or "..", so fall 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) { |