Instead of reimplementing ext4_match_ci, use the new libfs helper.
It should be fine to drop the fname->cf_name in the encrypted directory
case for the hash verification optimization because the only two ways
for fname->cf_name to be NULL on a case-insensitive lookup is
(1) if name under lookup has an invalid encoding and the FS is not in
strict mode; or
(2) if the directory is encrypted and we don't have the
key.
For case (1), it doesn't matter, because the lookup hash will be
generated with fname->usr_name, the same as the disk (fallback to
invalid encoding behavior on !strict mode). Case (2) is caught by the
previous check (!IS_ENCRYPTED(parent) ||
fscrypt_has_encryption_key(parent)), so we never reach this code.
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
fs/ext4/namei.c | 81 +++++++++++--------------------------------------
1 file changed, 17 insertions(+), 64 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 206fcf8fdc16..98295b03a57c 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1318,58 +1318,6 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
}
#if IS_ENABLED(CONFIG_UNICODE)
-/*
- * Test whether a case-insensitive directory entry matches the filename
- * being searched for. If quick is set, assume the name being looked up
- * is already in the casefolded form.
- *
- * Returns: 0 if the directory entry matches, more than 0 if it
- * doesn't match or less than zero on error.
- */
-static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
- u8 *de_name, size_t de_name_len, bool quick)
-{
- const struct super_block *sb = parent->i_sb;
- const struct unicode_map *um = sb->s_encoding;
- struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
- struct qstr entry = QSTR_INIT(de_name, de_name_len);
- int ret;
-
- if (IS_ENCRYPTED(parent)) {
- const struct fscrypt_str encrypted_name =
- FSTR_INIT(de_name, de_name_len);
-
- decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
- if (!decrypted_name.name)
- return -ENOMEM;
- ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
- &decrypted_name);
- if (ret < 0)
- goto out;
- entry.name = decrypted_name.name;
- entry.len = decrypted_name.len;
- }
-
- if (quick)
- ret = utf8_strncasecmp_folded(um, name, &entry);
- else
- ret = utf8_strncasecmp(um, name, &entry);
- if (ret < 0) {
- /* Handle invalid character sequence as either an error
- * or as an opaque byte sequence.
- */
- if (sb_has_strict_encoding(sb))
- ret = -EINVAL;
- else if (name->len != entry.len)
- ret = 1;
- else
- ret = !!memcmp(name->name, entry.name, entry.len);
- }
-out:
- kfree(decrypted_name.name);
- return ret;
-}
-
int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
struct ext4_filename *name)
{
@@ -1432,20 +1380,25 @@ static bool ext4_match(struct inode *parent,
#if IS_ENABLED(CONFIG_UNICODE)
if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
(!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
- if (fname->cf_name.name) {
- if (IS_ENCRYPTED(parent)) {
- if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
- fname->hinfo.minor_hash !=
- EXT4_DIRENT_MINOR_HASH(de)) {
+ int ret;
- return false;
- }
- }
- return !ext4_ci_compare(parent, &fname->cf_name,
- de->name, de->name_len, true);
+ if (IS_ENCRYPTED(parent) &&
+ (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
+ fname->hinfo.minor_hash != EXT4_DIRENT_MINOR_HASH(de)))
+ return false;
+
+ ret = generic_ci_match(parent, fname->usr_fname,
+ &fname->cf_name, de->name,
+ de->name_len);
+ if (ret < 0) {
+ /*
+ * Treat comparison errors as not a match. The
+ * only case where it happens is on a disk
+ * corruption or ENOMEM.
+ */
+ return false;
}
- return !ext4_ci_compare(parent, fname->usr_fname, de->name,
- de->name_len, false);
+ return ret;
}
#endif
--
2.36.1
