1 files changed, 115 insertions, 84 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 2d7525fbcf25..71fdc0dfa0d2 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -269,7 +269,7 @@ static match_table_t nfs_local_lock_tokens = {
 
 enum {
 	Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
-	Opt_vers_4_1,
+	Opt_vers_4_1, Opt_vers_4_2,
 
 	Opt_vers_err
 };
@@ -280,6 +280,7 @@ static match_table_t nfs_vers_tokens = {
 	{ Opt_vers_4, "4" },
 	{ Opt_vers_4_0, "4.0" },
 	{ Opt_vers_4_1, "4.1" },
+	{ Opt_vers_4_2, "4.2" },
 
 	{ Opt_vers_err, NULL }
 };
@@ -832,6 +833,7 @@ int nfs_show_stats(struct seq_file *m, struct dentry *root)
 		seq_printf(m, "\n\tnfsv4:\t");
 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
+		seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
 		show_sessions(m, nfss);
 		show_pnfs(m, nfss);
@@ -1097,6 +1099,10 @@ static int nfs_parse_version_string(char *string,
 		mnt->version = 4;
 		mnt->minorversion = 1;
 		break;
+	case Opt_vers_4_2:
+		mnt->version = 4;
+		mnt->minorversion = 2;
+		break;
 	default:
 		return 0;
 	}
@@ -1608,29 +1614,13 @@ out_security_failure:
 }
 
 /*
- * Select a security flavor for this mount.  The selected flavor
- * is planted in args->auth_flavors[0].
- *
- * Returns 0 on success, -EACCES on failure.
+ * Ensure that the specified authtype in args->auth_flavors[0] is supported by
+ * the server. Returns 0 if it's ok, and -EACCES if not.
  */
-static int nfs_select_flavor(struct nfs_parsed_mount_data *args,
-			      struct nfs_mount_request *request)
+static int nfs_verify_authflavor(struct nfs_parsed_mount_data *args,
+			rpc_authflavor_t *server_authlist, unsigned int count)
 {
-	unsigned int i, count = *(request->auth_flav_len);
-	rpc_authflavor_t flavor;
-
-	/*
-	 * The NFSv2 MNT operation does not return a flavor list.
-	 */
-	if (args->mount_server.version != NFS_MNT3_VERSION)
-		goto out_default;
-
-	/*
-	 * Certain releases of Linux's mountd return an empty
-	 * flavor list in some cases.
-	 */
-	if (count == 0)
-		goto out_default;
+	unsigned int i;
 
 	/*
 	 * If the sec= mount option is used, the specified flavor or AUTH_NULL
@@ -1640,60 +1630,19 @@ static int nfs_select_flavor(struct nfs_parsed_mount_data *args,
 	 * means that the server will ignore the rpc creds, so any flavor
 	 * can be used.
 	 */
-	if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) {
-		for (i = 0; i < count; i++) {
-			if (args->auth_flavors[0] == request->auth_flavs[i] ||
-			    request->auth_flavs[i] == RPC_AUTH_NULL)
-				goto out;
-		}
-		dfprintk(MOUNT, "NFS: auth flavor %d not supported by server\n",
-			args->auth_flavors[0]);
-		goto out_err;
-	}
-
-	/*
-	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
-	 * flavor listed first.  However, some servers list
-	 * AUTH_NULL first.  Avoid ever choosing AUTH_NULL.
-	 */
 	for (i = 0; i < count; i++) {
-		struct rpcsec_gss_info info;
-
-		flavor = request->auth_flavs[i];
-		switch (flavor) {
-		case RPC_AUTH_UNIX:
-			goto out_set;
-		case RPC_AUTH_NULL:
-			continue;
-		default:
-			if (rpcauth_get_gssinfo(flavor, &info) == 0)
-				goto out_set;
-		}
+		if (args->auth_flavors[0] == server_authlist[i] ||
+		    server_authlist[i] == RPC_AUTH_NULL)
+			goto out;
 	}
 
-	/*
-	 * As a last chance, see if the server list contains AUTH_NULL -
-	 * if it does, use the default flavor.
-	 */
-	for (i = 0; i < count; i++) {
-		if (request->auth_flavs[i] == RPC_AUTH_NULL)
-			goto out_default;
-	}
-
-	dfprintk(MOUNT, "NFS: no auth flavors in common with server\n");
-	goto out_err;
+	dfprintk(MOUNT, "NFS: auth flavor %u not supported by server\n",
+		args->auth_flavors[0]);
+	return -EACCES;
 
-out_default:
-	/* use default if flavor not already set */
-	flavor = (args->auth_flavors[0] == RPC_AUTH_MAXFLAVOR) ?
-		RPC_AUTH_UNIX : args->auth_flavors[0];
-out_set:
-	args->auth_flavors[0] = flavor;
 out:
-	dfprintk(MOUNT, "NFS: using auth flavor %d\n", args->auth_flavors[0]);
+	dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
 	return 0;
-out_err:
-	return -EACCES;
 }
 
 /*
@@ -1701,10 +1650,10 @@ out_err:
  * corresponding to the provided path.
  */
 static int nfs_request_mount(struct nfs_parsed_mount_data *args,
-			     struct nfs_fh *root_fh)
+			     struct nfs_fh *root_fh,
+			     rpc_authflavor_t *server_authlist,
+			     unsigned int *server_authlist_len)
 {
-	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
-	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
 	struct nfs_mount_request request = {
 		.sap		= (struct sockaddr *)
 						&args->mount_server.address,
@@ -1712,7 +1661,7 @@ static int nfs_request_mount(struct nfs_parsed_mount_data *args,
 		.protocol	= args->mount_server.protocol,
 		.fh		= root_fh,
 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
-		.auth_flav_len	= &server_authlist_len,
+		.auth_flav_len	= server_authlist_len,
 		.auth_flavs	= server_authlist,
 		.net		= args->net,
 	};
@@ -1756,24 +1705,92 @@ static int nfs_request_mount(struct nfs_parsed_mount_data *args,
 		return status;
 	}
 
-	return nfs_select_flavor(args, &request);
+	return 0;
 }
 
-struct dentry *nfs_try_mount(int flags, const char *dev_name,
-			     struct nfs_mount_info *mount_info,
-			     struct nfs_subversion *nfs_mod)
+static struct nfs_server *nfs_try_mount_request(struct nfs_mount_info *mount_info,
+					struct nfs_subversion *nfs_mod)
 {
 	int status;
-	struct nfs_server *server;
+	unsigned int i;
+	bool tried_auth_unix = false;
+	bool auth_null_in_list = false;
+	struct nfs_server *server = ERR_PTR(-EACCES);
+	struct nfs_parsed_mount_data *args = mount_info->parsed;
+	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
+	unsigned int authlist_len = ARRAY_SIZE(authlist);
+
+	status = nfs_request_mount(args, mount_info->mntfh, authlist,
+					&authlist_len);
+	if (status)
+		return ERR_PTR(status);
 
-	if (mount_info->parsed->need_mount) {
-		status = nfs_request_mount(mount_info->parsed, mount_info->mntfh);
+	/*
+	 * Was a sec= authflavor specified in the options? First, verify
+	 * whether the server supports it, and then just try to use it if so.
+	 */
+	if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) {
+		status = nfs_verify_authflavor(args, authlist, authlist_len);
+		dfprintk(MOUNT, "NFS: using auth flavor %u\n", args->auth_flavors[0]);
 		if (status)
 			return ERR_PTR(status);
+		return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+	}
+
+	/*
+	 * No sec= option was provided. RFC 2623, section 2.7 suggests we
+	 * SHOULD prefer the flavor listed first. However, some servers list
+	 * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
+	 */
+	for (i = 0; i < authlist_len; ++i) {
+		rpc_authflavor_t flavor;
+		struct rpcsec_gss_info info;
+
+		flavor = authlist[i];
+		switch (flavor) {
+		case RPC_AUTH_UNIX:
+			tried_auth_unix = true;
+			break;
+		case RPC_AUTH_NULL:
+			auth_null_in_list = true;
+			continue;
+		default:
+			if (rpcauth_get_gssinfo(flavor, &info) != 0)
+				continue;
+			/* Fallthrough */
+		}
+		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
+		args->auth_flavors[0] = flavor;
+		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+		if (!IS_ERR(server))
+			return server;
 	}
 
-	/* Get a volume representation */
-	server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+	/*
+	 * Nothing we tried so far worked. At this point, give up if we've
+	 * already tried AUTH_UNIX or if the server's list doesn't contain
+	 * AUTH_NULL
+	 */
+	if (tried_auth_unix || !auth_null_in_list)
+		return server;
+
+	/* Last chance! Try AUTH_UNIX */
+	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
+	args->auth_flavors[0] = RPC_AUTH_UNIX;
+	return nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+}
+
+struct dentry *nfs_try_mount(int flags, const char *dev_name,
+			     struct nfs_mount_info *mount_info,
+			     struct nfs_subversion *nfs_mod)
+{
+	struct nfs_server *server;
+
+	if (mount_info->parsed->need_mount)
+		server = nfs_try_mount_request(mount_info, nfs_mod);
+	else
+		server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
+
 	if (IS_ERR(server))
 		return ERR_CAST(server);
 
@@ -2412,7 +2429,21 @@ static int nfs_bdi_register(struct nfs_server *server)
 int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
 			struct nfs_mount_info *mount_info)
 {
-	return security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts);
+	int error;
+	unsigned long kflags = 0, kflags_out = 0;
+	if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL)
+		kflags |= SECURITY_LSM_NATIVE_LABELS;
+
+	error = security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts,
+						kflags, &kflags_out);
+	if (error)
+		goto err;
+
+	if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL &&
+		!(kflags_out & SECURITY_LSM_NATIVE_LABELS))
+		NFS_SB(s)->caps &= ~NFS_CAP_SECURITY_LABEL;
+err:
+	return error;
 }
 EXPORT_SYMBOL_GPL(nfs_set_sb_security);