NFSD: Replace NFS3_ACCESS_FULL in nfsd4_access()

nfsd_access() owns three static tables that map on-the-wire ACCESS bits to NFSD_MAY flags, and every NFS version shares them. That puts protocol-version specifics in the version-agnostic VFS layer. The NFSv4.2 extended-attribute bits are wedged into the NFSv3 tables under CONFIG_NFSD_V4.

Give each version its own tables in its proc code and pass the matching set into nfsd_access() as a new argument.

Splitting the tables also stops the NFSv2-ACL and NFSv3 ACCESS paths from answering for the NFSv4.2 extended-attribute bits. Both use the NFSv4-augmented table whenever CONFIG_NFSD_V4 is set, so an NFSv3 request that sets an xattr bit has it echoed back in the reply even though those bits are undefined for v3.

Signed-off-by Chuck Lever <[email protected]>

---
 fs/nfsd/nfs2acl.c  | 46 ++++++++++++++++++++++++++-
 fs/nfsd/nfs3proc.c | 41 +++++++++++++++++++++++-
 fs/nfsd/nfs4proc.c | 42 +++++++++++++++++++++++--
 fs/nfsd/vfs.c      | 78 ++++++++++------------------------------------
 fs/nfsd/vfs.h      | 15 ++++++++-
 5 files changed, 155 insertions(+), 67 deletions(-)

fs/nfsd/nfs2acl.c +45 -1

index aba69dd278a1..33610deda3b0 100644
@@ -16,6 +16,48 @@
 
 #define NFSDDBG_FACILITY		NFSDDBG_PROC
 
+/*
+ * These maps are identical to the NFSv3 maps (nfs3proc.c). This enables
+ * the behavior of the two versions to diverge if needed.
+ */
+static const struct nfsd_access_map nfsd2_regaccess[] = {
+	{ NFS3_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC				},
+	{ NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC		},
+	{ NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE				},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_map nfsd2_diraccess[] = {
+	{ NFS3_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC				},
+	{ NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
+	{ NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE		},
+	{ NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE				},
+	{ 0,			0					}
+};
+
+/*
+ * Some clients - Solaris 2.6 at least, make an access call to the NFS
+ * server to check for access for things like /dev/null (which really,
+ * NFSD doesn't care about).  So NFSD provides simple access checking
+ * for those objects, looking mainly at mode bits, ignoring read-only
+ * filesystem checks.
+ */
+static const struct nfsd_access_map nfsd2_otheraccess[] = {
+	{ NFS3_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC				},
+	{ NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
+	{ NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_maps nfsd2_access_maps = {
+	.regular	= nfsd2_regaccess,
+	.directory	= nfsd2_diraccess,
+	.other		= nfsd2_otheraccess,
+};
+
 /*
  * NULL call.
  */

@@ -181,7 +223,9 @@ static __be32 nfsacld_proc_access(struct svc_rqst *rqstp)
 
 	fh_copy(&resp->fh, &argp->fh);
 	resp->access = argp->access;
-	resp->status = nfsd_access(rqstp, &resp->fh, &resp->access, NULL);
+
+	resp->status = nfsd_access(rqstp, &resp->fh, &nfsd2_access_maps,
+				   &resp->access, NULL);
 	if (resp->status != nfs_ok)
 		goto out;
 	resp->status = fh_getattr(&resp->fh, &resp->stat);

fs/nfsd/nfs3proc.c +40 -1

index 19ab0a713d82..17bbe5d13f18 100644
@@ -49,6 +49,44 @@ static bool nfsd3_time_in_range(const struct iattr *iap)
 	return true;
 }
 
+static const struct nfsd_access_map nfsd3_regaccess[] = {
+	{ NFS3_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC				},
+	{ NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC		},
+	{ NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE				},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_map nfsd3_diraccess[] = {
+	{ NFS3_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC				},
+	{ NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
+	{ NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE		},
+	{ NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE				},
+	{ 0,			0					}
+};
+
+/*
+ * Some clients - Solaris 2.6 at least, make an access call to the NFS
+ * server to check for access for things like /dev/null (which really,
+ * NFSD doesn't care about).  So NFSD provides simple access checking
+ * for those objects, looking mainly at mode bits, ignoring read-only
+ * filesystem checks.
+ */
+static const struct nfsd_access_map nfsd3_otheraccess[] = {
+	{ NFS3_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC				},
+	{ NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
+	{ NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_maps nfsd3_access_maps = {
+	.regular	= nfsd3_regaccess,
+	.directory	= nfsd3_diraccess,
+	.other		= nfsd3_otheraccess,
+};
+
 static int nfsd3_iocb_flags(enum nfs3_stable_how how)
 {
 	switch (how) {

@@ -186,7 +224,8 @@ nfsd3_proc_access(struct svc_rqst *rqstp)
 
 	fh_copy(&resp->fh, &argp->fh);
 	resp->access = argp->access;
-	resp->status = nfsd_access(rqstp, &resp->fh, &resp->access, NULL);
+	resp->status = nfsd_access(rqstp, &resp->fh, &nfsd3_access_maps,
+				   &resp->access, NULL);
 	resp->status = nfsd3_map_status(resp->status);
 	return rpc_success;
 }

fs/nfsd/nfs4proc.c +39 -3

index a2bea8947ef5..54593f4667f8 100644
@@ -72,6 +72,43 @@ MODULE_PARM_DESC(nfsd4_ssc_umount_timeout,
 
 #define NFSDDBG_FACILITY		NFSDDBG_PROC
 
+static const struct nfsd_access_map nfsd4_regaccess[] = {
+	{ NFS4_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS4_ACCESS_EXECUTE,	NFSD_MAY_EXEC				},
+	{ NFS4_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC		},
+	{ NFS4_ACCESS_EXTEND,	NFSD_MAY_WRITE				},
+	{ NFS4_ACCESS_XAREAD,	NFSD_MAY_READ				},
+	{ NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE				},
+	{ NFS4_ACCESS_XALIST,	NFSD_MAY_READ				},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_map nfsd4_diraccess[] = {
+	{ NFS4_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS4_ACCESS_LOOKUP,	NFSD_MAY_EXEC				},
+	{ NFS4_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
+	{ NFS4_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE		},
+	{ NFS4_ACCESS_DELETE,	NFSD_MAY_REMOVE				},
+	{ NFS4_ACCESS_XAREAD,	NFSD_MAY_READ				},
+	{ NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE				},
+	{ NFS4_ACCESS_XALIST,	NFSD_MAY_READ				},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_map nfsd4_otheraccess[] = {
+	{ NFS4_ACCESS_READ,	NFSD_MAY_READ				},
+	{ NFS4_ACCESS_EXECUTE,	NFSD_MAY_EXEC				},
+	{ NFS4_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
+	{ NFS4_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
+	{ 0,			0					}
+};
+
+static const struct nfsd_access_maps nfsd4_access_maps = {
+	.regular	= nfsd4_regaccess,
+	.directory	= nfsd4_diraccess,
+	.other		= nfsd4_otheraccess,
+};
+
 static int nfsd4_iocb_flags(enum stable_how4 how)
 {
 	switch (how) {

@@ -851,10 +888,9 @@ nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 
 	if (access->ac_req_access & ~access_full)
 		return nfserr_inval;
-
 	access->ac_resp_access = access->ac_req_access;
-	return nfsd_access(rqstp, &cstate->current_fh, &access->ac_resp_access,
-			   &access->ac_supported);
+	return nfsd_access(rqstp, &cstate->current_fh, &nfsd4_access_maps,
+			   &access->ac_resp_access, &access->ac_supported);
 }
 
 static __be32

fs/nfsd/vfs.c +17 -61

index 807e09521e0c..6d865f4f9ba3 100644
@@ -782,64 +782,21 @@ __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
 }
 #endif /* defined(CONFIG_NFSD_V4) */
 
-/*
- * Check server access rights to a file system object
+/**
+ * nfsd_access - Check caller's access rights to a file system object
+ * @rqstp: RPC transaction context
+ * @fhp: target NFS filehandle
+ * @maps: tables mapping on-the-wire access bits to NFSD_MAY flags
+ * @access: requested access bits on entry, permitted bits on return
+ * @supported: optional output of the access bits the server supports
+ *
+ * Return: nfs_ok on success, otherwise an nfserr status code
  */
-struct accessmap {
-	u32		access;
-	int		how;
-};
-static struct accessmap	nfs3_regaccess[] = {
-    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
-    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
-    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
-    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
-
-#ifdef CONFIG_NFSD_V4
-    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
-    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
-    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
-#endif
-
-    {	0,			0				}
-};
-
-static struct accessmap	nfs3_diraccess[] = {
-    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
-    {	NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC			},
-    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
-    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
-    {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
-
-#ifdef CONFIG_NFSD_V4
-    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
-    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
-    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
-#endif
-
-    {	0,			0				}
-};
-
-static struct accessmap	nfs3_anyaccess[] = {
-	/* Some clients - Solaris 2.6 at least, make an access call
-	 * to the server to check for access for things like /dev/null
-	 * (which really, the server doesn't care about).  So
-	 * We provide simple access checking for them, looking
-	 * mainly at mode bits, and we make sure to ignore read-only
-	 * filesystem checks
-	 */
-    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
-    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
-    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
-    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
-
-    {	0,			0				}
-};
-
-__be32
-nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
+__be32 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
+		   const struct nfsd_access_maps *maps,
+		   u32 *access, u32 *supported)
 {
-	struct accessmap	*map;
+	const struct nfsd_access_map *map;
 	struct svc_export	*export;
 	struct dentry		*dentry;
 	u32			query, result = 0, sresult = 0;

@@ -853,12 +810,11 @@ nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *suppor
 	dentry = fhp->fh_dentry;
 
 	if (d_is_reg(dentry))
-		map = nfs3_regaccess;
+		map = maps->regular;
 	else if (d_is_dir(dentry))
-		map = nfs3_diraccess;
+		map = maps->directory;
 	else
-		map = nfs3_anyaccess;
-
+		map = maps->other;
 
 	query = *access;
 	for  (; map->access; map++) {

@@ -868,7 +824,7 @@ nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *suppor
 			sresult |= map->access;
 
 			err2 = nfsd_permission(&rqstp->rq_cred, export,
-					       dentry, map->how);
+					       dentry, map->may);
 			switch (err2) {
 			case nfs_ok:
 				result |= map->access;

fs/nfsd/vfs.h +11 -0

index aa7679d4c54a..3aa4522ca0a4 100644
@@ -37,6 +37,17 @@
 #define NFSD_MAY_CREATE		(NFSD_MAY_EXEC|NFSD_MAY_WRITE)
 #define NFSD_MAY_REMOVE		(NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC)
 
+struct nfsd_access_map {
+	u32		access;
+	int		may;
+};
+
+struct nfsd_access_maps {
+	const struct nfsd_access_map	*regular;
+	const struct nfsd_access_map	*directory;
+	const struct nfsd_access_map	*other;
+};
+
 struct nfsd_file;
 
 /*

Clean up: Remove an NFSv3 constant (NFS3_ACCESS_FULL) used inside an NFSv4 code path.

After this patch is applied, the nfs3.h header is no longer an implicit dependency of nfs4proc.c for this value. The definition itself stays in nfs3.h to avoid a kernel-user space API regression.

Signed-off-by Chuck Lever <[email protected]>

---
 fs/nfsd/nfs4proc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

fs/nfsd/nfs4proc.c +0 -0

index 03c32db618cd..a2bea8947ef5 100644