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author | Eric Biggers <ebiggers@google.com> | 2022-05-14 10:59:29 -0700 |
---|---|---|
committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2022-05-17 11:19:23 -0700 |
commit | b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d (patch) | |
tree | 01e37a83ad3acc9d6115d49787eb63927056c787 /fs | |
parent | c81d5bae404abc6b257667e84d39b9b50c7063d4 (diff) | |
download | linux-stable-b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d.tar.gz linux-stable-b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d.tar.bz2 linux-stable-b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d.zip |
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')
-rw-r--r-- | fs/f2fs/dir.c | 3 | ||||
-rw-r--r-- | fs/f2fs/f2fs.h | 10 | ||||
-rw-r--r-- | fs/f2fs/hash.c | 11 |
3 files changed, 13 insertions, 11 deletions
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index a0e51937d92e..d5bd7932fb64 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -82,7 +82,8 @@ int f2fs_init_casefolded_name(const struct inode *dir, #if IS_ENABLED(CONFIG_UNICODE) struct super_block *sb = dir->i_sb; - if (IS_CASEFOLDED(dir)) { + if (IS_CASEFOLDED(dir) && + !is_dot_dotdot(fname->usr_fname->name, fname->usr_fname->len)) { fname->cf_name.name = f2fs_kmem_cache_alloc(f2fs_cf_name_slab, GFP_NOFS, false, F2FS_SB(sb)); if (!fname->cf_name.name) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 492af5b96de1..e9e32bc814df 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -508,11 +508,11 @@ struct f2fs_filename { #if IS_ENABLED(CONFIG_UNICODE) /* * For casefolded directories: the casefolded name, but it's left NULL - * if the original name is not valid Unicode, if the directory is both - * casefolded and encrypted and its encryption key is unavailable, or if - * the filesystem is doing an internal operation where usr_fname is also - * NULL. In all these cases we fall back to treating the name as an - * opaque byte sequence. + * if the original name is not valid Unicode, if the original name is + * "." or "..", if the directory is both casefolded and encrypted and + * its encryption key is unavailable, or if the filesystem is doing an + * internal operation where usr_fname is also NULL. In all these cases + * we fall back to treating the name as an opaque byte sequence. */ struct fscrypt_str cf_name; #endif 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) { |