exfat: handle unreconized benign secondary entries

Sony PXW-Z280 camera add vendor allocation entries to directory of
pictures. Currently, linux exfat does not support it and the file is
not visible. This patch handle vendor extension and allocation entries
as unreconized benign secondary entries. As described in the specification,
it is recognized but ignored, and when deleting directory entry set,
the associated clusters allocation are removed as well as benign secondary
directory entries.

Reported-by: Barócsi Dénes <[e-mail]>
Reviewed-by: Sungjong Seo <[e-mail]>
Reviewed-by: Yuezhang Mo <[e-mail]>
Signed-off-by: Namjae Jeon <[e-mail]>

fs/exfat/dir.c

···
 
 }
 
-static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
+static int exfat_get_uniname_from_ext_entry(struct super_block *sb,
 		struct exfat_chain *p_dir, int entry, unsigned short *uniname)
 {
-	int i;
+	int i, err;
 	struct exfat_entry_set_cache es;
 
-	if (exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES))
-		return;
+	err = exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES);
+	if (err)
+		return err;
 
 	/*
 	 * First entry  : file entry
···
 	}
 
 	exfat_put_dentry_set(&es, false);
+	return 0;
 }
 
 /* read a directory entry from the opened directory */
 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
 {
-	int i, dentries_per_clu, num_ext;
+	int i, dentries_per_clu, num_ext, err;
 	unsigned int type, clu_offset, max_dentries;
 	struct exfat_chain dir, clu;
 	struct exfat_uni_name uni_name;
···
 					0);
 
 			*uni_name.name = 0x0;
-			exfat_get_uniname_from_ext_entry(sb, &clu, i,
+			err = exfat_get_uniname_from_ext_entry(sb, &clu, i,
 				uni_name.name);
+			if (err) {
+				brelse(bh);
+				continue;
+			}
 			exfat_utf16_to_nls(sb, &uni_name,
 				dir_entry->namebuf.lfn,
 				dir_entry->namebuf.lfnbuf_len);
···
 			return TYPE_ACL;
 		return TYPE_CRITICAL_SEC;
 	}
+
+	if (ep->type == EXFAT_VENDOR_EXT)
+		return TYPE_VENDOR_EXT;
+	if (ep->type == EXFAT_VENDOR_ALLOC)
+		return TYPE_VENDOR_ALLOC;
+
 	return TYPE_BENIGN_SEC;
 }
 
···
 	return ret;
 }
 
+static void exfat_free_benign_secondary_clusters(struct inode *inode,
+		struct exfat_dentry *ep)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_chain dir;
+	unsigned int start_clu =
+		le32_to_cpu(ep->dentry.generic_secondary.start_clu);
+	u64 size = le64_to_cpu(ep->dentry.generic_secondary.size);
+	unsigned char flags = ep->dentry.generic_secondary.flags;
+
+	if (!(flags & ALLOC_POSSIBLE) || !start_clu || !size)
+		return;
+
+	exfat_chain_set(&dir, start_clu,
+			EXFAT_B_TO_CLU_ROUND_UP(size, EXFAT_SB(sb)),
+			flags);
+	exfat_free_cluster(inode, &dir);
+}
+
 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 		int entry, int num_entries, struct exfat_uni_name *p_uniname)
 {
···
 		if (!ep)
 			return -EIO;
 
+		if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
+			exfat_free_benign_secondary_clusters(inode, ep);
+
 		exfat_init_name_entry(ep, uniname);
 		exfat_update_bh(bh, sync);
 		brelse(bh);
···
 		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh);
 		if (!ep)
 			return -EIO;
+
+		if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
+			exfat_free_benign_secondary_clusters(inode, ep);
 
 		exfat_set_entry_type(ep, TYPE_DELETED);
 		exfat_update_bh(bh, IS_DIRSYNC(inode));
···
 	ES_MODE_GET_STRM_ENTRY,
 	ES_MODE_GET_NAME_ENTRY,
 	ES_MODE_GET_CRITICAL_SEC_ENTRY,
+	ES_MODE_GET_BENIGN_SEC_ENTRY,
 };
 
 static bool exfat_validate_entry(unsigned int type,
···
 		if  (type != TYPE_FILE && type != TYPE_DIR)
 			return false;
 		*mode = ES_MODE_GET_FILE_ENTRY;
-		return true;
+		break;
 	case ES_MODE_GET_FILE_ENTRY:
 		if (type != TYPE_STREAM)
 			return false;
 		*mode = ES_MODE_GET_STRM_ENTRY;
-		return true;
+		break;
 	case ES_MODE_GET_STRM_ENTRY:
 		if (type != TYPE_EXTEND)
 			return false;
 		*mode = ES_MODE_GET_NAME_ENTRY;
-		return true;
+		break;
 	case ES_MODE_GET_NAME_ENTRY:
-		if (type == TYPE_STREAM)
+		if (type & TYPE_BENIGN_SEC)
+			*mode = ES_MODE_GET_BENIGN_SEC_ENTRY;
+		else if (type != TYPE_EXTEND)
 			return false;
-		if (type != TYPE_EXTEND) {
-			if (!(type & TYPE_CRITICAL_SEC))
-				return false;
-			*mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
-		}
-		return true;
-	case ES_MODE_GET_CRITICAL_SEC_ENTRY:
-		if (type == TYPE_EXTEND || type == TYPE_STREAM)
+		break;
+	case ES_MODE_GET_BENIGN_SEC_ENTRY:
+		/* Assume unreconized benign secondary entry */
+		if (!(type & TYPE_BENIGN_SEC))
 			return false;
-		if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
-			return false;
-		return true;
+		break;
 	default:
-		WARN_ON_ONCE(1);
 		return false;
 	}
+
+	return true;
 }
 
 struct exfat_dentry *exfat_get_dentry_cached(
···
 
 		type = exfat_get_entry_type(ext_ep);
 		brelse(bh);
-		if (type == TYPE_EXTEND || type == TYPE_STREAM)
+		if (type & TYPE_CRITICAL_SEC || type & TYPE_BENIGN_SEC)
 			count++;
-		else
-			break;
 	}
 	return count;
 }

fs/exfat/exfat_fs.h

···
 #define TYPE_PADDING		0x0402
 #define TYPE_ACLTAB		0x0403
 #define TYPE_BENIGN_SEC		0x0800
+#define TYPE_VENDOR_EXT		0x0801
+#define TYPE_VENDOR_ALLOC	0x0802
 
 #define MAX_CHARSET_SIZE	6 /* max size of multi-byte character */
 #define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */

fs/exfat/exfat_raw.h

···
 	((sbi)->num_clusters - EXFAT_RESERVED_CLUSTERS)
 
 /* AllocationPossible and NoFatChain field in GeneralSecondaryFlags Field */
+#define ALLOC_POSSIBLE		0x01
 #define ALLOC_FAT_CHAIN		0x01
 #define ALLOC_NO_FAT_CHAIN	0x03
 
···
 #define EXFAT_STREAM		0xC0	/* stream entry */
 #define EXFAT_NAME		0xC1	/* file name entry */
 #define EXFAT_ACL		0xC2	/* stream entry */
+#define EXFAT_VENDOR_EXT	0xE0	/* vendor extension entry */
+#define EXFAT_VENDOR_ALLOC	0xE1	/* vendor allocation entry */
 
 #define IS_EXFAT_CRITICAL_PRI(x)	(x < 0xA0)
 #define IS_EXFAT_BENIGN_PRI(x)		(x < 0xC0)
···
 			__le32 start_clu;
 			__le64 size;
 		} __packed upcase; /* up-case table directory entry */
+		struct {
+			__u8 flags;
+			__u8 vendor_guid[16];
+			__u8 vendor_defined[14];
+		} __packed vendor_ext; /* vendor extension directory entry */
+		struct {
+			__u8 flags;
+			__u8 vendor_guid[16];
+			__u8 vendor_defined[2];
+			__le32 start_clu;
+			__le64 size;
+		} __packed vendor_alloc; /* vendor allocation directory entry */
+		struct {
+			__u8 flags;
+			__u8 custom_defined[18];
+			__le32 start_clu;
+			__le64 size;
+		} __packed generic_secondary; /* generic secondary directory entry */
 	} __packed dentry;
 } __packed;