makefs: Fix cd9660 filename buffer maximum length

The maximum length is 30 characters for name and extension, two
separators (. and ;) and 5 characters for file version from 1 to 32767,
which is 37 characters.  Add one for the null term as we treat these
buffers as C strings.

This is not an issue in practice, as the file version is always 1 in
makefs.

While here, drop `_WITH_PADDING` from the macro name and update the
previously-unused ISO_FILENAME_MAXLENGTH for the corrected length.
A 0x00 padding byte is used by ISO9660 when needed for alignment, which
can be the null byte at the end of the string.

Use sizeof where appropriate.

Reviewed by:	kevans
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D48193

usr.sbin/makefs/cd9660.c

@@ -497,7 +497,7 @@ cd9660_makefs(const char *image, const char *dir, fsnode *root,
 	real_root->isoDirRecord = emalloc(sizeof(*real_root->isoDirRecord));
 	/* Leave filename blank for root */
 	memset(real_root->isoDirRecord->name, 0,
-	    ISO_FILENAME_MAXLENGTH_WITH_PADDING);
+	    sizeof(real_root->isoDirRecord->name));
 
 	real_root->level = 0;
 	diskStructure->rootNode = real_root;
@@ -796,10 +796,10 @@ static int
 cd9660_translate_node_common(iso9660_disk *diskStructure, cd9660node *newnode)
 {
 	u_char flag;
-	char temp[ISO_FILENAME_MAXLENGTH_WITH_PADDING];
+	char temp[ISO_FILENAME_MAXLENGTH];
 
 	/* Now populate the isoDirRecord structure */
-	memset(temp, 0, ISO_FILENAME_MAXLENGTH_WITH_PADDING);
+	memset(temp, 0, sizeof(temp));
 
 	(void)cd9660_convert_filename(diskStructure, newnode->node->name,
 	    temp, sizeof(temp), !(S_ISDIR(newnode->node->type)));
@@ -1044,7 +1044,7 @@ cd9660_rename_filename(iso9660_disk *diskStructure, cd9660node *iter, int num,
 	else
 		maxlength = ISO_FILENAME_MAXLENGTH_BEFORE_VERSION;
 
-	tmp = emalloc(ISO_FILENAME_MAXLENGTH_WITH_PADDING);
+	tmp = emalloc(ISO_FILENAME_MAXLENGTH);
 
 	while (i < num && iter) {
 		powers = 1;
@@ -1105,8 +1105,7 @@ cd9660_rename_filename(iso9660_disk *diskStructure, cd9660node *iter, int num,
 		while (digits > 0) {
 			digit = (int)(temp / powers);
 			temp = temp - digit * powers;
-			snprintf(&tmp[numbts],
-			    ISO_FILENAME_MAXLENGTH_WITH_PADDING - numbts,
+			snprintf(&tmp[numbts], ISO_FILENAME_MAXLENGTH - numbts,
 			    "%d", digit);
 			digits--;
 			numbts++;
@@ -1153,8 +1152,7 @@ cd9660_copy_filenames(iso9660_disk *diskStructure, cd9660node *node)
 
 	TAILQ_FOREACH(cn, &node->cn_children, cn_next_child) {
 		cd9660_copy_filenames(diskStructure, cn);
-		memcpy(cn->o_name, cn->isoDirRecord->name,
-		    ISO_FILENAME_MAXLENGTH_WITH_PADDING);
+		memcpy(cn->o_name, cn->isoDirRecord->name, sizeof(cn->o_name));
 	}
 }
 
@@ -1277,7 +1275,7 @@ cd9660_rrip_move_directory(iso9660_disk *diskStructure, cd9660node *dir)
 	/* TODO: Inherit permissions / ownership (basically the entire inode) */
 
 	/* Set the new name */
-	memset(dir->isoDirRecord->name, 0, ISO_FILENAME_MAXLENGTH_WITH_PADDING);
+	memset(dir->isoDirRecord->name, 0, sizeof(dir->isoDirRecord->name));
 	strncpy(dir->isoDirRecord->name, newname, 8);
 	dir->isoDirRecord->length[0] = 34 + 8;
 	dir->isoDirRecord->name_len[0] = 8;

usr.sbin/makefs/cd9660.h

@@ -72,8 +72,7 @@
 
 /*30 for name and extension, as well as version number and padding bit*/
 #define ISO_FILENAME_MAXLENGTH_BEFORE_VERSION 30
-#define ISO_FILENAME_MAXLENGTH	36
-#define ISO_FILENAME_MAXLENGTH_WITH_PADDING 37
+#define ISO_FILENAME_MAXLENGTH	38
 
 #define ISO_FLAG_CLEAR 0x00
 #define ISO_FLAG_HIDDEN 0x01
@@ -118,7 +117,7 @@ typedef struct _iso_directory_record_cd9660 {
 	u_char interleave		[ISODCL (28, 28)];	/* 711 */
 	u_char volume_sequence_number	[ISODCL (29, 32)];	/* 723 */
 	u_char name_len			[ISODCL (33, 33)];	/* 711 */
-	char name			[ISO_FILENAME_MAXLENGTH_WITH_PADDING];
+	char name			[ISO_FILENAME_MAXLENGTH];
 } iso_directory_record_cd9660;
 
 /* TODO: Lots of optimization of this structure */
@@ -154,7 +153,7 @@ typedef struct _cd9660node {
 	int fileRecordSize;/*copy of a variable, int for quicker calculations*/
 
 	/* Old name, used for renaming - needs to be optimized but low priority */
-	char o_name [ISO_FILENAME_MAXLENGTH_WITH_PADDING];
+	char o_name [ISO_FILENAME_MAXLENGTH];
 
 	/***** SPACE RESERVED FOR EXTENSIONS *****/
 	/* For memory efficiency's sake - we should move this to a separate struct
@@ -194,7 +193,7 @@ typedef struct _path_table_entry
 	u_char extended_attribute_length[ISODCL (2, 2)];
 	u_char first_sector[ISODCL (3, 6)];
 	u_char parent_number[ISODCL (7, 8)];
-	char name[ISO_FILENAME_MAXLENGTH_WITH_PADDING];
+	char name[ISO_FILENAME_MAXLENGTH];
 } path_table_entry;
 
 typedef struct _volume_descriptor