1 files changed, 540 insertions, 0 deletions
diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
new file mode 100644
index 000000000..dda5c3e65
--- /dev/null
+++ b/fs/nfs/mount_clnt.c
@@ -0,0 +1,540 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * In-kernel MOUNT protocol client
+ *
+ * Copyright (C) 1997, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/uio.h>
+#include <linux/net.h>
+#include <linux/in.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/sched.h>
+#include <linux/nfs_fs.h>
+#include "internal.h"
+
+#define NFSDBG_FACILITY	NFSDBG_MOUNT
+
+/*
+ * Defined by RFC 1094, section A.3; and RFC 1813, section 5.1.4
+ */
+#define MNTPATHLEN		(1024)
+
+/*
+ * XDR data type sizes
+ */
+#define encode_dirpath_sz	(1 + XDR_QUADLEN(MNTPATHLEN))
+#define MNT_status_sz		(1)
+#define MNT_fhandle_sz		XDR_QUADLEN(NFS2_FHSIZE)
+#define MNT_fhandlev3_sz	XDR_QUADLEN(NFS3_FHSIZE)
+#define MNT_authflav3_sz	(1 + NFS_MAX_SECFLAVORS)
+
+/*
+ * XDR argument and result sizes
+ */
+#define MNT_enc_dirpath_sz	encode_dirpath_sz
+#define MNT_dec_mountres_sz	(MNT_status_sz + MNT_fhandle_sz)
+#define MNT_dec_mountres3_sz	(MNT_status_sz + MNT_fhandlev3_sz + \
+				 MNT_authflav3_sz)
+
+/*
+ * Defined by RFC 1094, section A.5
+ */
+enum {
+	MOUNTPROC_NULL		= 0,
+	MOUNTPROC_MNT		= 1,
+	MOUNTPROC_DUMP		= 2,
+	MOUNTPROC_UMNT		= 3,
+	MOUNTPROC_UMNTALL	= 4,
+	MOUNTPROC_EXPORT	= 5,
+};
+
+/*
+ * Defined by RFC 1813, section 5.2
+ */
+enum {
+	MOUNTPROC3_NULL		= 0,
+	MOUNTPROC3_MNT		= 1,
+	MOUNTPROC3_DUMP		= 2,
+	MOUNTPROC3_UMNT		= 3,
+	MOUNTPROC3_UMNTALL	= 4,
+	MOUNTPROC3_EXPORT	= 5,
+};
+
+static const struct rpc_program mnt_program;
+
+/*
+ * Defined by OpenGroup XNFS Version 3W, chapter 8
+ */
+enum mountstat {
+	MNT_OK			= 0,
+	MNT_EPERM		= 1,
+	MNT_ENOENT		= 2,
+	MNT_EACCES		= 13,
+	MNT_EINVAL		= 22,
+};
+
+static struct {
+	u32 status;
+	int errno;
+} mnt_errtbl[] = {
+	{ .status = MNT_OK,			.errno = 0,		},
+	{ .status = MNT_EPERM,			.errno = -EPERM,	},
+	{ .status = MNT_ENOENT,			.errno = -ENOENT,	},
+	{ .status = MNT_EACCES,			.errno = -EACCES,	},
+	{ .status = MNT_EINVAL,			.errno = -EINVAL,	},
+};
+
+/*
+ * Defined by RFC 1813, section 5.1.5
+ */
+enum mountstat3 {
+	MNT3_OK			= 0,		/* no error */
+	MNT3ERR_PERM		= 1,		/* Not owner */
+	MNT3ERR_NOENT		= 2,		/* No such file or directory */
+	MNT3ERR_IO		= 5,		/* I/O error */
+	MNT3ERR_ACCES		= 13,		/* Permission denied */
+	MNT3ERR_NOTDIR		= 20,		/* Not a directory */
+	MNT3ERR_INVAL		= 22,		/* Invalid argument */
+	MNT3ERR_NAMETOOLONG	= 63,		/* Filename too long */
+	MNT3ERR_NOTSUPP		= 10004,	/* Operation not supported */
+	MNT3ERR_SERVERFAULT	= 10006,	/* A failure on the server */
+};
+
+static struct {
+	u32 status;
+	int errno;
+} mnt3_errtbl[] = {
+	{ .status = MNT3_OK,			.errno = 0,		},
+	{ .status = MNT3ERR_PERM,		.errno = -EPERM,	},
+	{ .status = MNT3ERR_NOENT,		.errno = -ENOENT,	},
+	{ .status = MNT3ERR_IO,			.errno = -EIO,		},
+	{ .status = MNT3ERR_ACCES,		.errno = -EACCES,	},
+	{ .status = MNT3ERR_NOTDIR,		.errno = -ENOTDIR,	},
+	{ .status = MNT3ERR_INVAL,		.errno = -EINVAL,	},
+	{ .status = MNT3ERR_NAMETOOLONG,	.errno = -ENAMETOOLONG,	},
+	{ .status = MNT3ERR_NOTSUPP,		.errno = -ENOTSUPP,	},
+	{ .status = MNT3ERR_SERVERFAULT,	.errno = -EREMOTEIO,	},
+};
+
+struct mountres {
+	int errno;
+	struct nfs_fh *fh;
+	unsigned int *auth_count;
+	rpc_authflavor_t *auth_flavors;
+};
+
+struct mnt_fhstatus {
+	u32 status;
+	struct nfs_fh *fh;
+};
+
+/**
+ * nfs_mount - Obtain an NFS file handle for the given host and path
+ * @info: pointer to mount request arguments
+ *
+ * Uses default timeout parameters specified by underlying transport. On
+ * successful return, the auth_flavs list and auth_flav_len will be populated
+ * with the list from the server or a faked-up list if the server didn't
+ * provide one.
+ */
+int nfs_mount(struct nfs_mount_request *info)
+{
+	struct mountres	result = {
+		.fh		= info->fh,
+		.auth_count	= info->auth_flav_len,
+		.auth_flavors	= info->auth_flavs,
+	};
+	struct rpc_message msg	= {
+		.rpc_argp	= info->dirpath,
+		.rpc_resp	= &result,
+	};
+	struct rpc_create_args args = {
+		.net		= info->net,
+		.protocol	= info->protocol,
+		.address	= info->sap,
+		.addrsize	= info->salen,
+		.servername	= info->hostname,
+		.program	= &mnt_program,
+		.version	= info->version,
+		.authflavor	= RPC_AUTH_UNIX,
+		.cred		= current_cred(),
+	};
+	struct rpc_clnt		*mnt_clnt;
+	int			status;
+
+	dprintk("NFS: sending MNT request for %s:%s\n",
+		(info->hostname ? info->hostname : "server"),
+			info->dirpath);
+
+	if (strlen(info->dirpath) > MNTPATHLEN)
+		return -ENAMETOOLONG;
+
+	if (info->noresvport)
+		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
+
+	mnt_clnt = rpc_create(&args);
+	if (IS_ERR(mnt_clnt))
+		goto out_clnt_err;
+
+	if (info->version == NFS_MNT3_VERSION)
+		msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
+	else
+		msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
+
+	status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
+	rpc_shutdown_client(mnt_clnt);
+
+	if (status < 0)
+		goto out_call_err;
+	if (result.errno != 0)
+		goto out_mnt_err;
+
+	dprintk("NFS: MNT request succeeded\n");
+	status = 0;
+
+	/*
+	 * If the server didn't provide a flavor list, allow the
+	 * client to try any flavor.
+	 */
+	if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
+		dprintk("NFS: Faking up auth_flavs list\n");
+		info->auth_flavs[0] = RPC_AUTH_NULL;
+		*info->auth_flav_len = 1;
+	}
+out:
+	return status;
+
+out_clnt_err:
+	status = PTR_ERR(mnt_clnt);
+	dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
+	goto out;
+
+out_call_err:
+	dprintk("NFS: MNT request failed, status=%d\n", status);
+	goto out;
+
+out_mnt_err:
+	dprintk("NFS: MNT server returned result %d\n", result.errno);
+	status = result.errno;
+	goto out;
+}
+
+/**
+ * nfs_umount - Notify a server that we have unmounted this export
+ * @info: pointer to umount request arguments
+ *
+ * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
+ * use UDP.
+ */
+void nfs_umount(const struct nfs_mount_request *info)
+{
+	static const struct rpc_timeout nfs_umnt_timeout = {
+		.to_initval = 1 * HZ,
+		.to_maxval = 3 * HZ,
+		.to_retries = 2,
+	};
+	struct rpc_create_args args = {
+		.net		= info->net,
+		.protocol	= IPPROTO_UDP,
+		.address	= info->sap,
+		.addrsize	= info->salen,
+		.timeout	= &nfs_umnt_timeout,
+		.servername	= info->hostname,
+		.program	= &mnt_program,
+		.version	= info->version,
+		.authflavor	= RPC_AUTH_UNIX,
+		.flags		= RPC_CLNT_CREATE_NOPING,
+		.cred		= current_cred(),
+	};
+	struct rpc_message msg	= {
+		.rpc_argp	= info->dirpath,
+	};
+	struct rpc_clnt *clnt;
+	int status;
+
+	if (strlen(info->dirpath) > MNTPATHLEN)
+		return;
+
+	if (info->noresvport)
+		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
+
+	clnt = rpc_create(&args);
+	if (IS_ERR(clnt))
+		goto out_clnt_err;
+
+	dprintk("NFS: sending UMNT request for %s:%s\n",
+		(info->hostname ? info->hostname : "server"), info->dirpath);
+
+	if (info->version == NFS_MNT3_VERSION)
+		msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
+	else
+		msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
+
+	status = rpc_call_sync(clnt, &msg, 0);
+	rpc_shutdown_client(clnt);
+
+	if (unlikely(status < 0))
+		goto out_call_err;
+
+	return;
+
+out_clnt_err:
+	dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
+			PTR_ERR(clnt));
+	return;
+
+out_call_err:
+	dprintk("NFS: UMNT request failed, status=%d\n", status);
+}
+
+/*
+ * XDR encode/decode functions for MOUNT
+ */
+
+static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
+{
+	const u32 pathname_len = strlen(pathname);
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4 + pathname_len);
+	xdr_encode_opaque(p, pathname, pathname_len);
+}
+
+static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
+				const void *dirpath)
+{
+	encode_mntdirpath(xdr, dirpath);
+}
+
+/*
+ * RFC 1094: "A non-zero status indicates some sort of error.  In this
+ * case, the status is a UNIX error number."  This can be problematic
+ * if the server and client use different errno values for the same
+ * error.
+ *
+ * However, the OpenGroup XNFS spec provides a simple mapping that is
+ * independent of local errno values on the server and the client.
+ */
+static int decode_status(struct xdr_stream *xdr, struct mountres *res)
+{
+	unsigned int i;
+	u32 status;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	status = be32_to_cpup(p);
+
+	for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
+		if (mnt_errtbl[i].status == status) {
+			res->errno = mnt_errtbl[i].errno;
+			return 0;
+		}
+	}
+
+	dprintk("NFS: unrecognized MNT status code: %u\n", status);
+	res->errno = -EACCES;
+	return 0;
+}
+
+static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
+{
+	struct nfs_fh *fh = res->fh;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, NFS2_FHSIZE);
+	if (unlikely(p == NULL))
+		return -EIO;
+
+	fh->size = NFS2_FHSIZE;
+	memcpy(fh->data, p, NFS2_FHSIZE);
+	return 0;
+}
+
+static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
+				struct xdr_stream *xdr,
+				void *data)
+{
+	struct mountres *res = data;
+	int status;
+
+	status = decode_status(xdr, res);
+	if (unlikely(status != 0 || res->errno != 0))
+		return status;
+	return decode_fhandle(xdr, res);
+}
+
+static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
+{
+	unsigned int i;
+	u32 status;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	status = be32_to_cpup(p);
+
+	for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
+		if (mnt3_errtbl[i].status == status) {
+			res->errno = mnt3_errtbl[i].errno;
+			return 0;
+		}
+	}
+
+	dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
+	res->errno = -EACCES;
+	return 0;
+}
+
+static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
+{
+	struct nfs_fh *fh = res->fh;
+	u32 size;
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+
+	size = be32_to_cpup(p);
+	if (size > NFS3_FHSIZE || size == 0)
+		return -EIO;
+
+	p = xdr_inline_decode(xdr, size);
+	if (unlikely(p == NULL))
+		return -EIO;
+
+	fh->size = size;
+	memcpy(fh->data, p, size);
+	return 0;
+}
+
+static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
+{
+	rpc_authflavor_t *flavors = res->auth_flavors;
+	unsigned int *count = res->auth_count;
+	u32 entries, i;
+	__be32 *p;
+
+	if (*count == 0)
+		return 0;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	entries = be32_to_cpup(p);
+	dprintk("NFS: received %u auth flavors\n", entries);
+	if (entries > NFS_MAX_SECFLAVORS)
+		entries = NFS_MAX_SECFLAVORS;
+
+	p = xdr_inline_decode(xdr, 4 * entries);
+	if (unlikely(p == NULL))
+		return -EIO;
+
+	if (entries > *count)
+		entries = *count;
+
+	for (i = 0; i < entries; i++) {
+		flavors[i] = be32_to_cpup(p++);
+		dprintk("NFS:   auth flavor[%u]: %d\n", i, flavors[i]);
+	}
+	*count = i;
+
+	return 0;
+}
+
+static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
+				 struct xdr_stream *xdr,
+				 void *data)
+{
+	struct mountres *res = data;
+	int status;
+
+	status = decode_fhs_status(xdr, res);
+	if (unlikely(status != 0 || res->errno != 0))
+		return status;
+	status = decode_fhandle3(xdr, res);
+	if (unlikely(status != 0)) {
+		res->errno = -EBADHANDLE;
+		return 0;
+	}
+	return decode_auth_flavors(xdr, res);
+}
+
+static const struct rpc_procinfo mnt_procedures[] = {
+	[MOUNTPROC_MNT] = {
+		.p_proc		= MOUNTPROC_MNT,
+		.p_encode	= mnt_xdr_enc_dirpath,
+		.p_decode	= mnt_xdr_dec_mountres,
+		.p_arglen	= MNT_enc_dirpath_sz,
+		.p_replen	= MNT_dec_mountres_sz,
+		.p_statidx	= MOUNTPROC_MNT,
+		.p_name		= "MOUNT",
+	},
+	[MOUNTPROC_UMNT] = {
+		.p_proc		= MOUNTPROC_UMNT,
+		.p_encode	= mnt_xdr_enc_dirpath,
+		.p_arglen	= MNT_enc_dirpath_sz,
+		.p_statidx	= MOUNTPROC_UMNT,
+		.p_name		= "UMOUNT",
+	},
+};
+
+static const struct rpc_procinfo mnt3_procedures[] = {
+	[MOUNTPROC3_MNT] = {
+		.p_proc		= MOUNTPROC3_MNT,
+		.p_encode	= mnt_xdr_enc_dirpath,
+		.p_decode	= mnt_xdr_dec_mountres3,
+		.p_arglen	= MNT_enc_dirpath_sz,
+		.p_replen	= MNT_dec_mountres3_sz,
+		.p_statidx	= MOUNTPROC3_MNT,
+		.p_name		= "MOUNT",
+	},
+	[MOUNTPROC3_UMNT] = {
+		.p_proc		= MOUNTPROC3_UMNT,
+		.p_encode	= mnt_xdr_enc_dirpath,
+		.p_arglen	= MNT_enc_dirpath_sz,
+		.p_statidx	= MOUNTPROC3_UMNT,
+		.p_name		= "UMOUNT",
+	},
+};
+
+static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
+static const struct rpc_version mnt_version1 = {
+	.number		= 1,
+	.nrprocs	= ARRAY_SIZE(mnt_procedures),
+	.procs		= mnt_procedures,
+	.counts		= mnt_counts,
+};
+
+static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
+static const struct rpc_version mnt_version3 = {
+	.number		= 3,
+	.nrprocs	= ARRAY_SIZE(mnt3_procedures),
+	.procs		= mnt3_procedures,
+	.counts		= mnt3_counts,
+};
+
+static const struct rpc_version *mnt_version[] = {
+	NULL,
+	&mnt_version1,
+	NULL,
+	&mnt_version3,
+};
+
+static struct rpc_stat mnt_stats;
+
+static const struct rpc_program mnt_program = {
+	.name		= "mount",
+	.number		= NFS_MNT_PROGRAM,
+	.nrvers		= ARRAY_SIZE(mnt_version),
+	.version	= mnt_version,
+	.stats		= &mnt_stats,
+};