[PATCH 6.1 147/215] nfsd: allow disabling NFSv2 at compile time

Greg Kroah-Hartman
2024-03-04T21:49:38Z

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 2f3a4b2ac2f28b9be78ad21f401f31e263845214 ]

rpc.nfsd stopped supporting NFSv2 a year ago. Take the next logical
step toward deprecating it and allow NFSv2 support to be compiled out.

Add a new CONFIG_NFSD_V2 option that can be turned off and rework the
CONFIG_NFSD_V?_ACL option dependencies. Add a description that
discourages enabling it.

Also, change the description of CONFIG_NFSD to state that the always-on
version is now 3 instead of 2.

Finally, add an #ifdef around "case 2:" in __write_versions. When NFSv2
is disabled at compile time, this should make the kernel ignore attempts
to disable it at runtime, but still error out when trying to enable it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/nfsd/Kconfig | 19 +++++++++++++++----
fs/nfsd/Makefile | 5 +++--
fs/nfsd/nfsctl.c | 2 ++
fs/nfsd/nfsd.h | 3 +--
fs/nfsd/nfssvc.c | 6 ++++++
5 files changed, 27 insertions(+), 8 deletions(-)

--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -8,6 +8,7 @@ config NFSD
select SUNRPC
select EXPORTFS
select NFS_ACL_SUPPORT if NFSD_V2_ACL
+ select NFS_ACL_SUPPORT if NFSD_V3_ACL
depends on MULTIUSER
help
Choose Y here if you want to allow other computers to access
@@ -26,19 +27,29 @@ config NFSD

Below you can choose which versions of the NFS protocol are
available to clients mounting the NFS server on this system.
- Support for NFS version 2 (RFC 1094) is always available when
+ Support for NFS version 3 (RFC 1813) is always available when
CONFIG_NFSD is selected.

If unsure, say N.

-config NFSD_V2_ACL
- bool
+config NFSD_V2
+ bool "NFS server support for NFS version 2 (DEPRECATED)"
depends on NFSD
+ default n
+ help
+ NFSv2 (RFC 1094) was the first publicly-released version of NFS.
+ Unless you are hosting ancient (1990's era) NFS clients, you don't
+ need this.
+
+ If unsure, say N.
+
+config NFSD_V2_ACL
+ bool "NFS server support for the NFSv2 ACL protocol extension"
+ depends on NFSD_V2

config NFSD_V3_ACL
bool "NFS server support for the NFSv3 ACL protocol extension"
depends on NFSD
- select NFSD_V2_ACL
help
Solaris NFS servers support an auxiliary NFSv3 ACL protocol that
never became an official part of the NFS version 3 protocol.
--- a/fs/nfsd/Makefile
+++ b/fs/nfsd/Makefile
@@ -10,9 +10,10 @@ obj-$(CONFIG_NFSD) += nfsd.o
# this one should be compiled first, as the tracing macros can easily blow up
nfsd-y += trace.o

-nfsd-y += nfssvc.o nfsctl.o nfsproc.o nfsfh.o vfs.o \
- export.o auth.o lockd.o nfscache.o nfsxdr.o \
+nfsd-y += nfssvc.o nfsctl.o nfsfh.o vfs.o \
+ export.o auth.o lockd.o nfscache.o \
stats.o filecache.o nfs3proc.o nfs3xdr.o
+nfsd-$(CONFIG_NFSD_V2) += nfsproc.o nfsxdr.o
nfsd-$(CONFIG_NFSD_V2_ACL) += nfs2acl.o
nfsd-$(CONFIG_NFSD_V3_ACL) += nfs3acl.o
nfsd-$(CONFIG_NFSD_V4) += nfs4proc.o nfs4xdr.o nfs4state.o nfs4idmap.o \
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -581,7 +581,9 @@ static ssize_t __write_versions(struct f

cmd = sign == '-' ? NFSD_CLEAR : NFSD_SET;
switch(num) {
+#ifdef CONFIG_NFSD_V2
case 2:
+#endif
case 3:
nfsd_vers(nn, num, cmd);
break;
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -64,8 +64,7 @@ struct readdir_cd {

extern struct svc_program nfsd_program;
-extern const struct svc_version nfsd_version2, nfsd_version3,
- nfsd_version4;
+extern const struct svc_version nfsd_version2, nfsd_version3, nfsd_version4;
extern struct mutex nfsd_mutex;
extern spinlock_t nfsd_drc_lock;
extern unsigned long nfsd_drc_max_mem;
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -91,8 +91,12 @@ unsigned long nfsd_drc_mem_used;
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
static struct svc_stat nfsd_acl_svcstats;
static const struct svc_version *nfsd_acl_version[] = {
+# if defined(CONFIG_NFSD_V2_ACL)
[2] = &nfsd_acl_version2,
+# endif
+# if defined(CONFIG_NFSD_V3_ACL)
[3] = &nfsd_acl_version3,
+# endif
};

#define NFSD_ACL_MINVERS 2
@@ -116,7 +120,9 @@ static struct svc_stat nfsd_acl_svcstats
#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */

static const struct svc_version *nfsd_version[] = {
+#if defined(CONFIG_NFSD_V2)
[2] = &nfsd_version2,
+#endif
[3] = &nfsd_version3,
#if defined(CONFIG_NFSD_V4)
[4] = &nfsd_version4,