? a.out
? o
? x
? x.c
Index: dir.h
===================================================================
RCS file: /cvsroot/src/sys/ufs/ufs/dir.h,v
retrieving revision 1.25
diff -u -p -u -r1.25 dir.h
--- dir.h	1 Sep 2015 06:16:03 -0000	1.25
+++ dir.h	5 May 2019 01:28:31 -0000
@@ -111,8 +111,11 @@ struct	direct {
  * without the d_name field, plus enough space for the name with a terminating
  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
  */
+#define DIR_ROUNDUP	4
+#define UFS_NAMEROUNDUP(namlen)	(((namlen) + DIR_ROUNDUP) & ~(DIR_ROUNDUP - 1))
+#define UFS_NAMEPAD(namlen)	(DIR_ROUNDUP - ((namlen) & (DIR_ROUNDUP - 1)))
 #define	UFS_DIRECTSIZ(namlen) \
-	((sizeof(struct direct) - (FFS_MAXNAMLEN+1)) + (((namlen)+1 + 3) &~ 3))
+	((sizeof(struct direct) - (FFS_MAXNAMLEN+1)) + UFS_NAMEROUNDUP(namlen))
 
 #if (BYTE_ORDER == LITTLE_ENDIAN)
 #define UFS_DIRSIZ(oldfmt, dp, needswap)	\
Index: ufs_lookup.c
===================================================================
RCS file: /cvsroot/src/sys/ufs/ufs/ufs_lookup.c,v
retrieving revision 1.148
diff -u -p -u -r1.148 ufs_lookup.c
--- ufs_lookup.c	27 Oct 2017 12:25:15 -0000	1.148
+++ ufs_lookup.c	5 May 2019 01:28:31 -0000
@@ -793,10 +793,15 @@ void
 ufs_makedirentry(struct inode *ip, struct componentname *cnp,
     struct direct *newdirp)
 {
+	size_t namelen = cnp->cn_namelen;
+
 	newdirp->d_ino = ip->i_number;
-	newdirp->d_namlen = cnp->cn_namelen;
-	memcpy(newdirp->d_name, cnp->cn_nameptr, (size_t)cnp->cn_namelen);
-	newdirp->d_name[cnp->cn_namelen] = '\0';
+	newdirp->d_namlen = namelen;
+	memcpy(newdirp->d_name, cnp->cn_nameptr, namelen);
+
+	/* Zero out padding */
+	memset(&newdirp->d_name[namelen], 0, UFS_NAMEPAD(namelen));
+
 	if (FSFMT(ITOV(ip)))
 		newdirp->d_type = 0;
 	else