text: // 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_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_fhandle_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,
  };
  