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authorEric Biggers <ebiggers@google.com>2022-05-14 10:59:29 -0700
committerJaegeuk Kim <jaegeuk@kernel.org>2022-05-17 11:19:23 -0700
commitb5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d (patch)
tree01e37a83ad3acc9d6115d49787eb63927056c787 /fs/f2fs
parentc81d5bae404abc6b257667e84d39b9b50c7063d4 (diff)
downloadlinux-b5639bb4313b9d455fc9fc4768d23a5e4ca8cb9d.tar.bz2
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')
-rw-r--r--fs/f2fs/dir.c3
-rw-r--r--fs/f2fs/f2fs.h10
-rw-r--r--fs/f2fs/hash.c11
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) {