Subject: [PATCH v1 2/4] exports: Add an xprtsec= export option
From:   Chuck Lever <cel@kernel.org>
To:     SteveD@redhat.com
Cc:     linux-nfs@vger.kernel.org
Date:   Mon, 20 Mar 2023 10:35:38 -0400
Message-ID: <167932293857.3437.10836642078898996996.stgit@manet.1015granger.net>
In-Reply-To: <167932279970.3437.7130911928591001093.stgit@manet.1015granger.net>
References: <167932279970.3437.7130911928591001093.stgit@manet.1015granger.net>
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From: Chuck Lever <chuck.lever@oracle.com>

The overall goal is to enable administrators to require the use of
transport layer security when clients access particular exports.

This patch adds support to exportfs to parse and display a new
xprtsec= export option. The setting is not yet passed to the kernel.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 support/include/nfs/export.h |    6 +++
 support/include/nfslib.h     |   14 +++++++
 support/nfs/exports.c        |   85 ++++++++++++++++++++++++++++++++++++++++++
 utils/exportfs/exportfs.c    |    1 
 4 files changed, 106 insertions(+)

diff --git a/support/include/nfs/export.h b/support/include/nfs/export.h
index 0eca828ee3ad..b29c6fa4f554 100644
--- a/support/include/nfs/export.h
+++ b/support/include/nfs/export.h
@@ -40,4 +40,10 @@
 #define NFSEXP_OLD_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \
 					| NFSEXP_ALLSQUASH)
 
+enum {
+	NFSEXP_XPRTSEC_NONE = 1,
+	NFSEXP_XPRTSEC_TLS = 2,
+	NFSEXP_XPRTSEC_MTLS = 3,
+};
+
 #endif /* _NSF_EXPORT_H */
diff --git a/support/include/nfslib.h b/support/include/nfslib.h
index 6faba71bf0cd..9a188fb84790 100644
--- a/support/include/nfslib.h
+++ b/support/include/nfslib.h
@@ -62,6 +62,18 @@ struct sec_entry {
 	int flags;
 };
 
+#define XPRTSECMODE_COUNT 4
+
+struct xprtsec_info {
+	const char		*name;
+	int			number;
+};
+
+struct xprtsec_entry {
+	const struct xprtsec_info *info;
+	int			flags;
+};
+
 /*
  * Data related to a single exports entry as returned by getexportent.
  * FIXME: export options should probably be parsed at a later time to
@@ -83,6 +95,7 @@ struct exportent {
 	char *          e_fslocdata;
 	char *		e_uuid;
 	struct sec_entry e_secinfo[SECFLAVOR_COUNT+1];
+	struct xprtsec_entry e_xprtsec[XPRTSECMODE_COUNT + 1];
 	unsigned int	e_ttl;
 	char *		e_realpath;
 };
@@ -99,6 +112,7 @@ struct rmtabent {
 void			setexportent(char *fname, char *type);
 struct exportent *	getexportent(int,int);
 void 			secinfo_show(FILE *fp, struct exportent *ep);
+void			xprtsecinfo_show(FILE *fp, struct exportent *ep);
 void			putexportent(struct exportent *xep);
 void			endexportent(void);
 struct exportent *	mkexportent(char *hname, char *path, char *opts);
diff --git a/support/nfs/exports.c b/support/nfs/exports.c
index 7f12383981c3..da8ace3a65fd 100644
--- a/support/nfs/exports.c
+++ b/support/nfs/exports.c
@@ -99,6 +99,7 @@ static void init_exportent (struct exportent *ee, int fromkernel)
 	ee->e_fslocmethod = FSLOC_NONE;
 	ee->e_fslocdata = NULL;
 	ee->e_secinfo[0].flav = NULL;
+	ee->e_xprtsec[0].info = NULL;
 	ee->e_nsquids = 0;
 	ee->e_nsqgids = 0;
 	ee->e_uuid = NULL;
@@ -248,6 +249,17 @@ void secinfo_show(FILE *fp, struct exportent *ep)
 	}
 }
 
+void xprtsecinfo_show(FILE *fp, struct exportent *ep)
+{
+	struct xprtsec_entry *p1, *p2;
+
+	for (p1 = ep->e_xprtsec; p1->info; p1 = p2) {
+		fprintf(fp, ",xprtsec=%s", p1->info->name);
+		for (p2 = p1 + 1; p2->info && (p1->flags == p2->flags); p2++)
+			fprintf(fp, ":%s", p2->info->name);
+	}
+}
+
 static void
 fprintpath(FILE *fp, const char *path)
 {
@@ -344,6 +356,7 @@ putexportent(struct exportent *ep)
 	}
 	fprintf(fp, "anonuid=%d,anongid=%d", ep->e_anonuid, ep->e_anongid);
 	secinfo_show(fp, ep);
+	xprtsecinfo_show(fp, ep);
 	fprintf(fp, ")\n");
 }
 
@@ -482,6 +495,75 @@ static unsigned int parse_flavors(char *str, struct exportent *ep)
 	return out;
 }
 
+static const struct xprtsec_info xprtsec_name2info[] = {
+	{ "none",	NFSEXP_XPRTSEC_NONE },
+	{ "tls",	NFSEXP_XPRTSEC_TLS },
+	{ "mtls",	NFSEXP_XPRTSEC_MTLS },
+	{ NULL,		0 }
+};
+
+static const struct xprtsec_info *find_xprtsec_info(const char *name)
+{
+	const struct xprtsec_info *info;
+
+	for (info = xprtsec_name2info; info->name; info++)
+		if (strcmp(info->name, name) == 0)
+			return info;
+	return NULL;
+}
+
+/*
+ * Append the given xprtsec mode to the exportent's e_xprtsec array,
+ * or do nothing if it's already there. Returns the index of flavor in
+ * the resulting array in any case.
+ */
+static int xprtsec_addmode(const struct xprtsec_info *info, struct exportent *ep)
+{
+	struct xprtsec_entry *p;
+
+	for (p = ep->e_xprtsec; p->info; p++)
+		if (p->info == info || p->info->number == info->number)
+			return p - ep->e_xprtsec;
+
+	if (p - ep->e_xprtsec >= XPRTSECMODE_COUNT) {
+		xlog(L_ERROR, "more than %d xprtsec modes on an export\n",
+			XPRTSECMODE_COUNT);
+		return -1;
+	}
+	p->info = info;
+	p->flags = ep->e_flags;
+	(p + 1)->info = NULL;
+	return p - ep->e_xprtsec;
+}
+
+/*
+ * @str is a colon seperated list of transport layer security modes.
+ * Their order is recorded in @ep, and a bitmap corresponding to the
+ * list is returned.
+ *
+ * A zero return indicates an error.
+ */
+static unsigned int parse_xprtsec(char *str, struct exportent *ep)
+{
+	unsigned int out = 0;
+	char *name;
+
+	while ((name = strsep(&str, ":"))) {
+		const struct xprtsec_info *info = find_xprtsec_info(name);
+		int bit;
+
+		if (!info) {
+			xlog(L_ERROR, "unknown xprtsec mode %s\n", name);
+			return 0;
+		}
+		bit = xprtsec_addmode(info, ep);
+		if (bit < 0)
+			return 0;
+		out |= 1 << bit;
+	}
+	return out;
+}
+
 /* Sets the bits in @mask for the appropriate security flavor flags. */
 static void setflags(int mask, unsigned int active, struct exportent *ep)
 {
@@ -687,6 +769,9 @@ bad_option:
 			active = parse_flavors(opt+4, ep);
 			if (!active)
 				goto bad_option;
+		} else if (strncmp(opt, "xprtsec=", 8) == 0) {
+			if (!parse_xprtsec(opt + 8, ep))
+				goto bad_option;
 		} else {
 			xlog(L_ERROR, "%s:%d: unknown keyword \"%s\"\n",
 					flname, flline, opt);
diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
index 6d79a5b3480d..37b9e4b3612d 100644
--- a/utils/exportfs/exportfs.c
+++ b/utils/exportfs/exportfs.c
@@ -743,6 +743,7 @@ dump(int verbose, int export_format)
 #endif
 			}
 			secinfo_show(stdout, ep);
+			xprtsecinfo_show(stdout, ep);
 			printf("%c\n", (c != '(')? ')' : ' ');
 		}
 	}