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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: 7ad08a58bf
("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>
This commit is contained in:
parent
c81d5bae40
commit
b5639bb431
@ -82,7 +82,8 @@ int f2fs_init_casefolded_name(const struct inode *dir,
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#if IS_ENABLED(CONFIG_UNICODE)
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struct super_block *sb = dir->i_sb;
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if (IS_CASEFOLDED(dir)) {
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if (IS_CASEFOLDED(dir) &&
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!is_dot_dotdot(fname->usr_fname->name, fname->usr_fname->len)) {
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fname->cf_name.name = f2fs_kmem_cache_alloc(f2fs_cf_name_slab,
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GFP_NOFS, false, F2FS_SB(sb));
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if (!fname->cf_name.name)
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@ -508,11 +508,11 @@ struct f2fs_filename {
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#if IS_ENABLED(CONFIG_UNICODE)
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/*
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* For casefolded directories: the casefolded name, but it's left NULL
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* if the original name is not valid Unicode, if the directory is both
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* casefolded and encrypted and its encryption key is unavailable, or if
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* the filesystem is doing an internal operation where usr_fname is also
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* NULL. In all these cases we fall back to treating the name as an
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* opaque byte sequence.
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* if the original name is not valid Unicode, if the original name is
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* "." or "..", if the directory is both casefolded and encrypted and
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* its encryption key is unavailable, or if the filesystem is doing an
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* internal operation where usr_fname is also NULL. In all these cases
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* we fall back to treating the name as an opaque byte sequence.
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*/
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struct fscrypt_str cf_name;
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#endif
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@ -91,7 +91,7 @@ static u32 TEA_hash_name(const u8 *p, size_t len)
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/*
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* Compute @fname->hash. For all directories, @fname->disk_name must be set.
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* For casefolded directories, @fname->usr_fname must be set, and also
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* @fname->cf_name if the filename is valid Unicode.
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* @fname->cf_name if the filename is valid Unicode and is not "." or "..".
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*/
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void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname)
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{
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@ -110,10 +110,11 @@ void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname)
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/*
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* If the casefolded name is provided, hash it instead of the
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* on-disk name. If the casefolded name is *not* provided, that
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* should only be because the name wasn't valid Unicode, so fall
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* back to treating the name as an opaque byte sequence. Note
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* that to handle encrypted directories, the fallback must use
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* usr_fname (plaintext) rather than disk_name (ciphertext).
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* should only be because the name wasn't valid Unicode or was
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* "." or "..", so fall back to treating the name as an opaque
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* byte sequence. Note that to handle encrypted directories,
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* the fallback must use usr_fname (plaintext) rather than
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* disk_name (ciphertext).
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*/
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WARN_ON_ONCE(!fname->usr_fname->name);
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if (fname->cf_name.name) {
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