Fix off-by-one error in fstyp(8) and geom_label(4) that made them use

a single space (" ") as a CD9660 label name when no label was present.
Similar problem was also present in msdosfs label recognition.

PR:		200828
Differential Revision:	https://reviews.freebsd.org/D2830
Reviewed by:	asomers@, emaste@
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation

4 files changed, 19 insertions, 18 deletions

diff --git a/usr.sbin/fstyp/cd9660.c b/usr.sbin/fstyp/cd9660.c
index ee6af11..658af33 100644
--- a/usr.sbin/fstyp/cd9660.c
+++ b/usr.sbin/fstyp/cd9660.c
@@ -45,7 +45,6 @@ int
 fstyp_cd9660(FILE *fp, char *label, size_t size)
 {
 	char *sector, *volume;
-	int i;
 
 	sector = read_buf(fp, ISO9660_OFFSET, 512);
 	if (sector == NULL)
@@ -58,13 +57,6 @@ fstyp_cd9660(FILE *fp, char *label, size_t size)
 	bzero(label, size);
 	strlcpy(label, volume, MIN(size, VOLUME_LEN));
 	free(sector);
-	for (i = size - 1; i > 0; i--) {
-		if (label[i] == '\0')
-			continue;
-		else if (label[i] == ' ')
-			label[i] = '\0';
-		else
-			break;
-	}
+	rtrim(label, size);
 	return (0);
 }
diff --git a/usr.sbin/fstyp/fstyp.c b/usr.sbin/fstyp/fstyp.c
index d6a48f6..1a699eb 100644
--- a/usr.sbin/fstyp/fstyp.c
+++ b/usr.sbin/fstyp/fstyp.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -104,6 +105,21 @@ checked_strdup(const char *s)
 	return (c);
 }
 
+void
+rtrim(char *label, size_t size)
+{
+	ptrdiff_t i;
+
+	for (i = size - 1; i >= 0; i--) {
+		if (label[i] == '\0')
+			continue;
+		else if (label[i] == ' ')
+			label[i] = '\0';
+		else
+			break;
+	}
+}
+
 static void
 usage(void)
 {
diff --git a/usr.sbin/fstyp/fstyp.h b/usr.sbin/fstyp/fstyp.h
index 4474ffe..d4fd54f 100644
--- a/usr.sbin/fstyp/fstyp.h
+++ b/usr.sbin/fstyp/fstyp.h
@@ -36,6 +36,7 @@
 
 void	*read_buf(FILE *fp, off_t off, size_t len);
 char	*checked_strdup(const char *s);
+void	rtrim(char *label, size_t size);
 
 int	fstyp_cd9660(FILE *fp, char *label, size_t size);
 int	fstyp_ext2fs(FILE *fp, char *label, size_t size);
diff --git a/usr.sbin/fstyp/msdosfs.c b/usr.sbin/fstyp/msdosfs.c
index b299243..3d86802 100644
--- a/usr.sbin/fstyp/msdosfs.c
+++ b/usr.sbin/fstyp/msdosfs.c
@@ -48,7 +48,6 @@ fstyp_msdosfs(FILE *fp, char *label, size_t size)
 	FAT32_BSBPB *pfat32_bsbpb;
 	FAT_DES *pfat_entry;
 	uint8_t *sector0, *sector;
-	uint32_t i;
 
 	sector0 = NULL;
 	sector = NULL;
@@ -161,14 +160,7 @@ fstyp_msdosfs(FILE *fp, char *label, size_t size)
 	}
 
 endofchecks:
-	for (i = size - 1; i > 0; i--) {
-		if (label[i] == '\0')
-			continue;
-		else if (label[i] == ' ')
-			label[i] = '\0';
-		else
-			break;
-	}
+	rtrim(label, size);
 
 	free(sector0);
 	free(sector);