FreeBSD: Fix leaked strings in libspl mnttab

The FreeBSD implementations of various libspl functions for getting mounted device informantion were found to leak several strings which were being allocated in statfs2mnttab but never freed. The Solaris getmntany(3C) and related interfaces are expected to return strings residing in static buffers that need to be copied rather than freed by the caller. Use static thread-local storage to stash the mnttab structure strings from FreeBSD's statfs info rather than strings allocated on the heap by strdup(3). While here, remove some stray commented out lines. Signed-off-by: Ryan Moeller <[email protected]>
openzfs · Jan 11, 2022 · 9cae5d7 · 9cae5d7
1 parent d6c1bbd
commit 9cae5d7
Showing 1 changed file with 44 additions and 38 deletions.
diff --git a/lib/libspl/os/freebsd/mnttab.c b/lib/libspl/os/freebsd/mnttab.c
@@ -91,42 +91,6 @@ optadd(char *mntopts, size_t size, const char *opt)
 	strlcat(mntopts, opt, size);
 }
 
-void
-statfs2mnttab(struct statfs *sfs, struct mnttab *mp)
-{
-	static char mntopts[MNTMAXSTR];
-	long flags;
-
-	mntopts[0] = '\0';
-
-	flags = sfs->f_flags;
-#define	OPTADD(opt)	optadd(mntopts, sizeof (mntopts), (opt))
-	if (flags & MNT_RDONLY)
-		OPTADD(MNTOPT_RO);
-	else
-		OPTADD(MNTOPT_RW);
-	if (flags & MNT_NOSUID)
-		OPTADD(MNTOPT_NOSETUID);
-	else
-		OPTADD(MNTOPT_SETUID);
-	if (flags & MNT_UPDATE)
-		OPTADD(MNTOPT_REMOUNT);
-	if (flags & MNT_NOATIME)
-		OPTADD(MNTOPT_NOATIME);
-	else
-		OPTADD(MNTOPT_ATIME);
-	OPTADD(MNTOPT_NOXATTR);
-	if (flags & MNT_NOEXEC)
-		OPTADD(MNTOPT_NOEXEC);
-	else
-		OPTADD(MNTOPT_EXEC);
-#undef	OPTADD
-	mp->mnt_special = strdup(sfs->f_mntfromname);
-	mp->mnt_mountp = strdup(sfs->f_mntonname);
-	mp->mnt_fstype = strdup(sfs->f_fstypename);
-	mp->mnt_mntopts = strdup(mntopts);
-}
-
 static struct statfs *gsfs = NULL;
 static int allfs = 0;
 
@@ -163,10 +127,53 @@ statfs_init(void)
 	return (error);
 }
 
+#define BUFSIZE (sizeof (gsfs->f_fstypename) + sizeof (gsfs->f_mntfromname) + \
+    sizeof(gsfs->f_mntonname) + MNTMAXSTR)
+
+static __thread char buf[BUFSIZE];
+
+void
+statfs2mnttab(struct statfs *sfs, struct mnttab *mp)
+{
+	static char mntopts[MNTMAXSTR];
+	long flags;
+
+	mntopts[0] = '\0';
+
+	flags = sfs->f_flags;
+#define	OPTADD(opt)	optadd(mntopts, sizeof (mntopts), (opt))
+	if (flags & MNT_RDONLY)
+		OPTADD(MNTOPT_RO);
+	else
+		OPTADD(MNTOPT_RW);
+	if (flags & MNT_NOSUID)
+		OPTADD(MNTOPT_NOSETUID);
+	else
+		OPTADD(MNTOPT_SETUID);
+	if (flags & MNT_UPDATE)
+		OPTADD(MNTOPT_REMOUNT);
+	if (flags & MNT_NOATIME)
+		OPTADD(MNTOPT_NOATIME);
+	else
+		OPTADD(MNTOPT_ATIME);
+	OPTADD(MNTOPT_NOXATTR);
+	if (flags & MNT_NOEXEC)
+		OPTADD(MNTOPT_NOEXEC);
+	else
+		OPTADD(MNTOPT_EXEC);
+#undef	OPTADD
+	char *p = buf, *e = buf + BUFSIZE;
+#define	STASH(d, s)	p += 1 + strlcpy((d = p), s, e - p)
+	STASH(mp->mnt_special, sfs->f_mntfromname);
+	STASH(mp->mnt_mountp, sfs->f_mntonname);
+	STASH(mp->mnt_fstype, sfs->f_fstypename);
+	STASH(mp->mnt_mntopts, mntopts);
+#undef	STASH
+}
+
 int
 getmntany(FILE *fd __unused, struct mnttab *mgetp, struct mnttab *mrefp)
 {
-	//	struct statfs *sfs;
 	int i, error;
 
 	error = statfs_init();
@@ -195,7 +202,6 @@ getmntany(FILE *fd __unused, struct mnttab *mgetp, struct mnttab *mrefp)
 int
 getmntent(FILE *fp, struct mnttab *mp)
 {
-	//	struct statfs *sfs;
 	int error, nfs;
 
 	nfs = (int)lseek(fileno(fp), 0, SEEK_CUR);