1 files changed, 43 insertions, 46 deletions

diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index 5bc4dcd8fc03..049ce50cec9b 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -12,7 +12,6 @@
 #include <linux/types.h>
 #include <linux/fs.h>
 #include <linux/f2fs_fs.h>
-#include <linux/cryptohash.h>
 #include <linux/pagemap.h>
 #include <linux/unicode.h>
 
@@ -68,22 +67,9 @@ static void str2hashbuf(const unsigned char *msg, size_t len,
 		*buf++ = pad;
 }
 
-static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
-				struct fscrypt_name *fname)
+static u32 TEA_hash_name(const u8 *p, size_t len)
 {
-	__u32 hash;
-	f2fs_hash_t f2fs_hash;
-	const unsigned char *p;
 	__u32 in[8], buf[4];
-	const unsigned char *name = name_info->name;
-	size_t len = name_info->len;
-
-	/* encrypted bigname case */
-	if (fname && !fname->disk_name.name)
-		return cpu_to_le32(fname->hash);
-
-	if (is_dot_dotdot(name_info))
-		return 0;
 
 	/* Initialize the default seed for the hash checksum functions */
 	buf[0] = 0x67452301;
@@ -91,7 +77,6 @@ static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
 	buf[2] = 0x98badcfe;
 	buf[3] = 0x10325476;
 
-	p = name;
 	while (1) {
 		str2hashbuf(p, len, in, 4);
 		TEA_transform(buf, in);
@@ -100,41 +85,53 @@ static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
 			break;
 		len -= 16;
 	}
-	hash = buf[0];
-	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
-	return f2fs_hash;
+	return buf[0] & ~F2FS_HASH_COL_BIT;
 }
 
-f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
-		const struct qstr *name_info, struct fscrypt_name *fname)
+/*
+ * 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 and is not "." or "..".
+ */
+void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname)
 {
-#ifdef CONFIG_UNICODE
-	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
-	const struct unicode_map *um = sbi->s_encoding;
-	int r, dlen;
-	unsigned char *buff;
-	struct qstr folded;
-
-	if (!name_info->len || !IS_CASEFOLDED(dir))
-		goto opaque_seq;
-
-	buff = f2fs_kzalloc(sbi, sizeof(char) * PATH_MAX, GFP_KERNEL);
-	if (!buff)
-		return -ENOMEM;
-
-	dlen = utf8_casefold(um, name_info, buff, PATH_MAX);
-	if (dlen < 0) {
-		kvfree(buff);
-		goto opaque_seq;
+	const u8 *name = fname->disk_name.name;
+	size_t len = fname->disk_name.len;
+
+	WARN_ON_ONCE(!name);
+
+	if (is_dot_dotdot(name, len)) {
+		fname->hash = 0;
+		return;
 	}
-	folded.name = buff;
-	folded.len = dlen;
-	r = __f2fs_dentry_hash(&folded, fname);
 
-	kvfree(buff);
-	return r;
+#if IS_ENABLED(CONFIG_UNICODE)
+	if (IS_CASEFOLDED(dir)) {
+		/*
+		 * 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 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) {
+			name = fname->cf_name.name;
+			len = fname->cf_name.len;
+		} else {
+			name = fname->usr_fname->name;
+			len = fname->usr_fname->len;
+		}
+		if (IS_ENCRYPTED(dir)) {
+			struct qstr tmp = QSTR_INIT(name, len);
 
-opaque_seq:
+			fname->hash =
+				cpu_to_le32(fscrypt_fname_siphash(dir, &tmp));
+			return;
+		}
+	}
 #endif
-	return __f2fs_dentry_hash(name_info, fname);
+	fname->hash = cpu_to_le32(TEA_hash_name(name, len));
 }