root/fs/nfs/fs_context.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/fs/nfs/fs_context.c
 *
 * Copyright (C) 1992 Rick Sladkey
 * Conversion to new mount api Copyright (C) David Howells
 *
 * NFS mount handling.
 *
 * Split from fs/nfs/super.c by David Howells <dhowells@redhat.com>
 */

#include <linux/compat.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>

#include <net/handshake.h>

#include "nfs.h"
#include "internal.h"

#include "nfstrace.h"

#define NFSDBG_FACILITY         NFSDBG_MOUNT

#if IS_ENABLED(CONFIG_NFS_V3)
#define NFS_DEFAULT_VERSION 3
#else
#define NFS_DEFAULT_VERSION 2
#endif

#define NFS_MAX_CONNECTIONS 16

enum nfs_param {
        Opt_ac,
        Opt_acdirmax,
        Opt_acdirmin,
        Opt_acl,
        Opt_acregmax,
        Opt_acregmin,
        Opt_actimeo,
        Opt_addr,
        Opt_bg,
        Opt_bsize,
        Opt_clientaddr,
        Opt_cto,
        Opt_alignwrite,
        Opt_fatal_neterrors,
        Opt_fg,
        Opt_fscache,
        Opt_fscache_flag,
        Opt_hard,
        Opt_intr,
        Opt_local_lock,
        Opt_lock,
        Opt_lookupcache,
        Opt_migration,
        Opt_minorversion,
        Opt_mountaddr,
        Opt_mounthost,
        Opt_mountport,
        Opt_mountproto,
        Opt_mountvers,
        Opt_namelen,
        Opt_nconnect,
        Opt_max_connect,
        Opt_port,
        Opt_posix,
        Opt_proto,
        Opt_rdirplus,
        Opt_rdirplus_none,
        Opt_rdirplus_force,
        Opt_rdma,
        Opt_resvport,
        Opt_retrans,
        Opt_retry,
        Opt_rsize,
        Opt_sec,
        Opt_sharecache,
        Opt_sloppy,
        Opt_soft,
        Opt_softerr,
        Opt_softreval,
        Opt_source,
        Opt_tcp,
        Opt_timeo,
        Opt_trunkdiscovery,
        Opt_udp,
        Opt_v,
        Opt_vers,
        Opt_wsize,
        Opt_write,
        Opt_xprtsec,
        Opt_cert_serial,
        Opt_privkey_serial,
};

enum {
        Opt_fatal_neterrors_default,
        Opt_fatal_neterrors_enetunreach,
        Opt_fatal_neterrors_none,
};

static const struct constant_table nfs_param_enums_fatal_neterrors[] = {
        { "default",                    Opt_fatal_neterrors_default },
        { "ENETDOWN:ENETUNREACH",       Opt_fatal_neterrors_enetunreach },
        { "ENETUNREACH:ENETDOWN",       Opt_fatal_neterrors_enetunreach },
        { "none",                       Opt_fatal_neterrors_none },
        {}
};

enum {
        Opt_local_lock_all,
        Opt_local_lock_flock,
        Opt_local_lock_none,
        Opt_local_lock_posix,
};

static const struct constant_table nfs_param_enums_local_lock[] = {
        { "all",                Opt_local_lock_all },
        { "flock",      Opt_local_lock_flock },
        { "posix",      Opt_local_lock_posix },
        { "none",               Opt_local_lock_none },
        {}
};

enum {
        Opt_lookupcache_all,
        Opt_lookupcache_none,
        Opt_lookupcache_positive,
};

static const struct constant_table nfs_param_enums_lookupcache[] = {
        { "all",                Opt_lookupcache_all },
        { "none",               Opt_lookupcache_none },
        { "pos",                Opt_lookupcache_positive },
        { "positive",           Opt_lookupcache_positive },
        {}
};

enum {
        Opt_write_lazy,
        Opt_write_eager,
        Opt_write_wait,
};

static const struct constant_table nfs_param_enums_write[] = {
        { "lazy",               Opt_write_lazy },
        { "eager",              Opt_write_eager },
        { "wait",               Opt_write_wait },
        {}
};

static const struct fs_parameter_spec nfs_fs_parameters[] = {
        fsparam_flag_no("ac",           Opt_ac),
        fsparam_u32   ("acdirmax",      Opt_acdirmax),
        fsparam_u32   ("acdirmin",      Opt_acdirmin),
        fsparam_flag_no("acl",          Opt_acl),
        fsparam_u32   ("acregmax",      Opt_acregmax),
        fsparam_u32   ("acregmin",      Opt_acregmin),
        fsparam_u32   ("actimeo",       Opt_actimeo),
        fsparam_string("addr",          Opt_addr),
        fsparam_flag  ("bg",            Opt_bg),
        fsparam_u32   ("bsize",         Opt_bsize),
        fsparam_string("clientaddr",    Opt_clientaddr),
        fsparam_flag_no("cto",          Opt_cto),
        fsparam_flag_no("alignwrite",   Opt_alignwrite),
        fsparam_enum("fatal_neterrors", Opt_fatal_neterrors,
                     nfs_param_enums_fatal_neterrors),
        fsparam_flag  ("fg",            Opt_fg),
        fsparam_flag_no("fsc",          Opt_fscache_flag),
        fsparam_string("fsc",           Opt_fscache),
        fsparam_flag  ("hard",          Opt_hard),
        __fsparam(NULL, "intr",         Opt_intr,
                  fs_param_neg_with_no|fs_param_deprecated, NULL),
        fsparam_enum  ("local_lock",    Opt_local_lock, nfs_param_enums_local_lock),
        fsparam_flag_no("lock",         Opt_lock),
        fsparam_enum  ("lookupcache",   Opt_lookupcache, nfs_param_enums_lookupcache),
        fsparam_flag_no("migration",    Opt_migration),
        fsparam_u32   ("minorversion",  Opt_minorversion),
        fsparam_string("mountaddr",     Opt_mountaddr),
        fsparam_string("mounthost",     Opt_mounthost),
        fsparam_u32   ("mountport",     Opt_mountport),
        fsparam_string("mountproto",    Opt_mountproto),
        fsparam_u32   ("mountvers",     Opt_mountvers),
        fsparam_u32   ("namlen",        Opt_namelen),
        fsparam_u32   ("nconnect",      Opt_nconnect),
        fsparam_u32   ("max_connect",   Opt_max_connect),
        fsparam_string("nfsvers",       Opt_vers),
        fsparam_u32   ("port",          Opt_port),
        fsparam_flag_no("posix",        Opt_posix),
        fsparam_string("proto",         Opt_proto),
        fsparam_flag_no("rdirplus", Opt_rdirplus), // rdirplus|nordirplus
        fsparam_string("rdirplus",  Opt_rdirplus), // rdirplus=...
        fsparam_flag  ("rdma",          Opt_rdma),
        fsparam_flag_no("resvport",     Opt_resvport),
        fsparam_u32   ("retrans",       Opt_retrans),
        fsparam_string("retry",         Opt_retry),
        fsparam_u32   ("rsize",         Opt_rsize),
        fsparam_string("sec",           Opt_sec),
        fsparam_flag_no("sharecache",   Opt_sharecache),
        fsparam_flag  ("sloppy",        Opt_sloppy),
        fsparam_flag  ("soft",          Opt_soft),
        fsparam_flag  ("softerr",       Opt_softerr),
        fsparam_flag  ("softreval",     Opt_softreval),
        fsparam_string("source",        Opt_source),
        fsparam_flag  ("tcp",           Opt_tcp),
        fsparam_u32   ("timeo",         Opt_timeo),
        fsparam_flag_no("trunkdiscovery", Opt_trunkdiscovery),
        fsparam_flag  ("udp",           Opt_udp),
        fsparam_flag  ("v2",            Opt_v),
        fsparam_flag  ("v3",            Opt_v),
        fsparam_flag  ("v4",            Opt_v),
        fsparam_flag  ("v4.0",          Opt_v),
        fsparam_flag  ("v4.1",          Opt_v),
        fsparam_flag  ("v4.2",          Opt_v),
        fsparam_string("vers",          Opt_vers),
        fsparam_enum  ("write",         Opt_write, nfs_param_enums_write),
        fsparam_u32   ("wsize",         Opt_wsize),
        fsparam_string("xprtsec",       Opt_xprtsec),
        fsparam_s32("cert_serial",      Opt_cert_serial),
        fsparam_s32("privkey_serial",   Opt_privkey_serial),
        {}
};

enum {
        Opt_vers_2,
        Opt_vers_3,
        Opt_vers_4,
        Opt_vers_4_0,
        Opt_vers_4_1,
        Opt_vers_4_2,
};

static const struct constant_table nfs_vers_tokens[] = {
        { "2",          Opt_vers_2 },
        { "3",          Opt_vers_3 },
        { "4",          Opt_vers_4 },
        { "4.0",        Opt_vers_4_0 },
        { "4.1",        Opt_vers_4_1 },
        { "4.2",        Opt_vers_4_2 },
        {}
};

enum {
        Opt_xprt_rdma,
        Opt_xprt_rdma6,
        Opt_xprt_tcp,
        Opt_xprt_tcp6,
        Opt_xprt_udp,
        Opt_xprt_udp6,
        nr__Opt_xprt
};

static const struct constant_table nfs_xprt_protocol_tokens[] = {
        { "rdma",       Opt_xprt_rdma },
        { "rdma6",      Opt_xprt_rdma6 },
        { "tcp",        Opt_xprt_tcp },
        { "tcp6",       Opt_xprt_tcp6 },
        { "udp",        Opt_xprt_udp },
        { "udp6",       Opt_xprt_udp6 },
        {}
};

enum {
        Opt_sec_krb5,
        Opt_sec_krb5i,
        Opt_sec_krb5p,
        Opt_sec_lkey,
        Opt_sec_lkeyi,
        Opt_sec_lkeyp,
        Opt_sec_none,
        Opt_sec_spkm,
        Opt_sec_spkmi,
        Opt_sec_spkmp,
        Opt_sec_sys,
        nr__Opt_sec
};

static const struct constant_table nfs_secflavor_tokens[] = {
        { "krb5",       Opt_sec_krb5 },
        { "krb5i",      Opt_sec_krb5i },
        { "krb5p",      Opt_sec_krb5p },
        { "lkey",       Opt_sec_lkey },
        { "lkeyi",      Opt_sec_lkeyi },
        { "lkeyp",      Opt_sec_lkeyp },
        { "none",       Opt_sec_none },
        { "null",       Opt_sec_none },
        { "spkm3",      Opt_sec_spkm },
        { "spkm3i",     Opt_sec_spkmi },
        { "spkm3p",     Opt_sec_spkmp },
        { "sys",        Opt_sec_sys },
        {}
};

enum {
        Opt_xprtsec_none,
        Opt_xprtsec_tls,
        Opt_xprtsec_mtls,
        nr__Opt_xprtsec
};

static const struct constant_table nfs_xprtsec_policies[] = {
        { "none",       Opt_xprtsec_none },
        { "tls",        Opt_xprtsec_tls },
        { "mtls",       Opt_xprtsec_mtls },
        {}
};

static const struct constant_table nfs_rdirplus_tokens[] = {
        { "none",       Opt_rdirplus_none },
        { "force",      Opt_rdirplus_force },
        {}
};

/*
 * Sanity-check a server address provided by the mount command.
 *
 * Address family must be initialized, and address must not be
 * the ANY address for that family.
 */
static int nfs_verify_server_address(struct sockaddr_storage *addr)
{
        switch (addr->ss_family) {
        case AF_INET: {
                struct sockaddr_in *sa = (struct sockaddr_in *)addr;
                return sa->sin_addr.s_addr != htonl(INADDR_ANY);
        }
        case AF_INET6: {
                struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
                return !ipv6_addr_any(sa);
        }
        }

        return 0;
}

#ifdef CONFIG_NFS_DISABLE_UDP_SUPPORT
static bool nfs_server_transport_udp_invalid(const struct nfs_fs_context *ctx)
{
        return true;
}
#else
static bool nfs_server_transport_udp_invalid(const struct nfs_fs_context *ctx)
{
        if (ctx->version == 4)
                return true;
        return false;
}
#endif

/*
 * Sanity check the NFS transport protocol.
 */
static int nfs_validate_transport_protocol(struct fs_context *fc,
                                           struct nfs_fs_context *ctx)
{
        switch (ctx->nfs_server.protocol) {
        case XPRT_TRANSPORT_UDP:
                if (nfs_server_transport_udp_invalid(ctx))
                        goto out_invalid_transport_udp;
                break;
        case XPRT_TRANSPORT_TCP:
        case XPRT_TRANSPORT_RDMA:
                break;
        default:
                ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
        }

        if (ctx->xprtsec.policy != RPC_XPRTSEC_NONE)
                switch (ctx->nfs_server.protocol) {
                case XPRT_TRANSPORT_TCP:
                        ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP_TLS;
                        break;
                default:
                        goto out_invalid_xprtsec_policy;
        }

        return 0;
out_invalid_transport_udp:
        return nfs_invalf(fc, "NFS: Unsupported transport protocol udp");
out_invalid_xprtsec_policy:
        return nfs_invalf(fc, "NFS: Transport does not support xprtsec");
}

/*
 * For text based NFSv2/v3 mounts, the mount protocol transport default
 * settings should depend upon the specified NFS transport.
 */
static void nfs_set_mount_transport_protocol(struct nfs_fs_context *ctx)
{
        if (ctx->mount_server.protocol == XPRT_TRANSPORT_UDP ||
            ctx->mount_server.protocol == XPRT_TRANSPORT_TCP)
                        return;
        switch (ctx->nfs_server.protocol) {
        case XPRT_TRANSPORT_UDP:
                ctx->mount_server.protocol = XPRT_TRANSPORT_UDP;
                break;
        case XPRT_TRANSPORT_TCP:
        case XPRT_TRANSPORT_RDMA:
                ctx->mount_server.protocol = XPRT_TRANSPORT_TCP;
        }
}

/*
 * Add 'flavor' to 'auth_info' if not already present.
 * Returns true if 'flavor' ends up in the list, false otherwise
 */
static int nfs_auth_info_add(struct fs_context *fc,
                             struct nfs_auth_info *auth_info,
                             rpc_authflavor_t flavor)
{
        unsigned int i;
        unsigned int max_flavor_len = ARRAY_SIZE(auth_info->flavors);

        /* make sure this flavor isn't already in the list */
        for (i = 0; i < auth_info->flavor_len; i++) {
                if (flavor == auth_info->flavors[i])
                        return 0;
        }

        if (auth_info->flavor_len + 1 >= max_flavor_len)
                return nfs_invalf(fc, "NFS: too many sec= flavors");

        auth_info->flavors[auth_info->flavor_len++] = flavor;
        return 0;
}

/*
 * Parse the value of the 'sec=' option.
 */
static int nfs_parse_security_flavors(struct fs_context *fc,
                                      struct fs_parameter *param)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        rpc_authflavor_t pseudoflavor;
        char *string = param->string, *p;
        int ret;

        trace_nfs_mount_assign(param->key, string);

        while ((p = strsep(&string, ":")) != NULL) {
                if (!*p)
                        continue;
                switch (lookup_constant(nfs_secflavor_tokens, p, -1)) {
                case Opt_sec_none:
                        pseudoflavor = RPC_AUTH_NULL;
                        break;
                case Opt_sec_sys:
                        pseudoflavor = RPC_AUTH_UNIX;
                        break;
                case Opt_sec_krb5:
                        pseudoflavor = RPC_AUTH_GSS_KRB5;
                        break;
                case Opt_sec_krb5i:
                        pseudoflavor = RPC_AUTH_GSS_KRB5I;
                        break;
                case Opt_sec_krb5p:
                        pseudoflavor = RPC_AUTH_GSS_KRB5P;
                        break;
                case Opt_sec_lkey:
                        pseudoflavor = RPC_AUTH_GSS_LKEY;
                        break;
                case Opt_sec_lkeyi:
                        pseudoflavor = RPC_AUTH_GSS_LKEYI;
                        break;
                case Opt_sec_lkeyp:
                        pseudoflavor = RPC_AUTH_GSS_LKEYP;
                        break;
                case Opt_sec_spkm:
                        pseudoflavor = RPC_AUTH_GSS_SPKM;
                        break;
                case Opt_sec_spkmi:
                        pseudoflavor = RPC_AUTH_GSS_SPKMI;
                        break;
                case Opt_sec_spkmp:
                        pseudoflavor = RPC_AUTH_GSS_SPKMP;
                        break;
                default:
                        return nfs_invalf(fc, "NFS: sec=%s option not recognized", p);
                }

                ret = nfs_auth_info_add(fc, &ctx->auth_info, pseudoflavor);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int nfs_parse_xprtsec_policy(struct fs_context *fc,
                                    struct fs_parameter *param)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);

        trace_nfs_mount_assign(param->key, param->string);

        switch (lookup_constant(nfs_xprtsec_policies, param->string, -1)) {
        case Opt_xprtsec_none:
                ctx->xprtsec.policy = RPC_XPRTSEC_NONE;
                break;
        case Opt_xprtsec_tls:
                ctx->xprtsec.policy = RPC_XPRTSEC_TLS_ANON;
                break;
        case Opt_xprtsec_mtls:
                ctx->xprtsec.policy = RPC_XPRTSEC_TLS_X509;
                break;
        default:
                return nfs_invalf(fc, "NFS: Unrecognized transport security policy");
        }
        return 0;
}

static int nfs_parse_version_string(struct fs_context *fc,
                                    const char *string)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);

        ctx->flags &= ~NFS_MOUNT_VER3;
        switch (lookup_constant(nfs_vers_tokens, string, -1)) {
        case Opt_vers_2:
                ctx->version = 2;
                break;
        case Opt_vers_3:
                ctx->flags |= NFS_MOUNT_VER3;
                ctx->version = 3;
                break;
        case Opt_vers_4:
                /* Backward compatibility option. In future,
                 * the mount program should always supply
                 * a NFSv4 minor version number.
                 */
                ctx->version = 4;
                break;
        case Opt_vers_4_0:
                ctx->version = 4;
                ctx->minorversion = 0;
                break;
        case Opt_vers_4_1:
                ctx->version = 4;
                ctx->minorversion = 1;
                break;
        case Opt_vers_4_2:
                ctx->version = 4;
                ctx->minorversion = 2;
                break;
        default:
                return nfs_invalf(fc, "NFS: Unsupported NFS version");
        }
        return 0;
}

#ifdef CONFIG_KEYS
static int nfs_tls_key_verify(key_serial_t key_id)
{
        struct key *key = key_lookup(key_id);
        int error = 0;

        if (IS_ERR(key)) {
                pr_err("key id %08x not found\n", key_id);
                return PTR_ERR(key);
        }
        if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
            test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
                pr_err("key id %08x revoked\n", key_id);
                error = -EKEYREVOKED;
        }

        key_put(key);
        return error;
}
#else
static inline int nfs_tls_key_verify(key_serial_t key_id)
{
        return -ENOENT;
}
#endif /* CONFIG_KEYS */

/*
 * Parse a single mount parameter.
 */
static int nfs_fs_context_parse_param(struct fs_context *fc,
                                      struct fs_parameter *param)
{
        struct fs_parse_result result;
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        unsigned short protofamily, mountfamily;
        unsigned int len;
        int ret, opt;

        trace_nfs_mount_option(param);

        opt = fs_parse(fc, nfs_fs_parameters, param, &result);
        if (opt < 0)
                return (opt == -ENOPARAM && ctx->sloppy) ? 1 : opt;

        if (fc->security)
                ctx->has_sec_mnt_opts = 1;

        switch (opt) {
        case Opt_source:
                if (fc->source)
                        return nfs_invalf(fc, "NFS: Multiple sources not supported");
                fc->source = param->string;
                param->string = NULL;
                break;

                /*
                 * boolean options:  foo/nofoo
                 */
        case Opt_soft:
                ctx->flags |= NFS_MOUNT_SOFT;
                ctx->flags &= ~NFS_MOUNT_SOFTERR;
                break;
        case Opt_softerr:
                ctx->flags |= NFS_MOUNT_SOFTERR | NFS_MOUNT_SOFTREVAL;
                ctx->flags &= ~NFS_MOUNT_SOFT;
                break;
        case Opt_hard:
                ctx->flags &= ~(NFS_MOUNT_SOFT |
                                NFS_MOUNT_SOFTERR |
                                NFS_MOUNT_SOFTREVAL);
                break;
        case Opt_softreval:
                if (result.negated)
                        ctx->flags &= ~NFS_MOUNT_SOFTREVAL;
                else
                        ctx->flags |= NFS_MOUNT_SOFTREVAL;
                break;
        case Opt_posix:
                if (result.negated)
                        ctx->flags &= ~NFS_MOUNT_POSIX;
                else
                        ctx->flags |= NFS_MOUNT_POSIX;
                break;
        case Opt_cto:
                if (result.negated)
                        ctx->flags |= NFS_MOUNT_NOCTO;
                else
                        ctx->flags &= ~NFS_MOUNT_NOCTO;
                break;
        case Opt_trunkdiscovery:
                if (result.negated)
                        ctx->flags &= ~NFS_MOUNT_TRUNK_DISCOVERY;
                else
                        ctx->flags |= NFS_MOUNT_TRUNK_DISCOVERY;
                break;
        case Opt_alignwrite:
                if (result.negated)
                        ctx->flags |= NFS_MOUNT_NO_ALIGNWRITE;
                else
                        ctx->flags &= ~NFS_MOUNT_NO_ALIGNWRITE;
                break;
        case Opt_ac:
                if (result.negated)
                        ctx->flags |= NFS_MOUNT_NOAC;
                else
                        ctx->flags &= ~NFS_MOUNT_NOAC;
                break;
        case Opt_lock:
                if (result.negated) {
                        ctx->lock_status = NFS_LOCK_NOLOCK;
                        ctx->flags |= NFS_MOUNT_NONLM;
                        ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
                } else {
                        ctx->lock_status = NFS_LOCK_LOCK;
                        ctx->flags &= ~NFS_MOUNT_NONLM;
                        ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
                }
                break;
        case Opt_udp:
                ctx->flags &= ~NFS_MOUNT_TCP;
                ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
                break;
        case Opt_tcp:
        case Opt_rdma:
                ctx->flags |= NFS_MOUNT_TCP; /* for side protocols */
                ret = xprt_find_transport_ident(param->key);
                if (ret < 0)
                        goto out_bad_transport;
                ctx->nfs_server.protocol = ret;
                break;
        case Opt_acl:
                if (result.negated)
                        ctx->flags |= NFS_MOUNT_NOACL;
                else
                        ctx->flags &= ~NFS_MOUNT_NOACL;
                break;
        case Opt_rdirplus:
                if (result.negated) {
                        ctx->flags &= ~NFS_MOUNT_FORCE_RDIRPLUS;
                        ctx->flags |= NFS_MOUNT_NORDIRPLUS;
                } else if (!param->string) {
                        ctx->flags &= ~(NFS_MOUNT_NORDIRPLUS | NFS_MOUNT_FORCE_RDIRPLUS);
                } else {
                        switch (lookup_constant(nfs_rdirplus_tokens, param->string, -1)) {
                        case Opt_rdirplus_none:
                                ctx->flags &= ~NFS_MOUNT_FORCE_RDIRPLUS;
                                ctx->flags |= NFS_MOUNT_NORDIRPLUS;
                                break;
                        case Opt_rdirplus_force:
                                ctx->flags &= ~NFS_MOUNT_NORDIRPLUS;
                                ctx->flags |= NFS_MOUNT_FORCE_RDIRPLUS;
                                break;
                        default:
                                goto out_invalid_value;
                        }
                }
                break;
        case Opt_sharecache:
                if (result.negated)
                        ctx->flags |= NFS_MOUNT_UNSHARED;
                else
                        ctx->flags &= ~NFS_MOUNT_UNSHARED;
                break;
        case Opt_resvport:
                if (result.negated)
                        ctx->flags |= NFS_MOUNT_NORESVPORT;
                else
                        ctx->flags &= ~NFS_MOUNT_NORESVPORT;
                break;
        case Opt_fscache_flag:
                if (result.negated)
                        ctx->options &= ~NFS_OPTION_FSCACHE;
                else
                        ctx->options |= NFS_OPTION_FSCACHE;
                kfree(ctx->fscache_uniq);
                ctx->fscache_uniq = NULL;
                break;
        case Opt_fscache:
                trace_nfs_mount_assign(param->key, param->string);
                ctx->options |= NFS_OPTION_FSCACHE;
                kfree(ctx->fscache_uniq);
                ctx->fscache_uniq = param->string;
                param->string = NULL;
                break;
        case Opt_migration:
                if (result.negated)
                        ctx->options &= ~NFS_OPTION_MIGRATION;
                else
                        ctx->options |= NFS_OPTION_MIGRATION;
                break;

                /*
                 * options that take numeric values
                 */
        case Opt_port:
                if (result.uint_32 > USHRT_MAX)
                        goto out_of_bounds;
                ctx->nfs_server.port = result.uint_32;
                break;
        case Opt_rsize:
                ctx->rsize = result.uint_32;
                break;
        case Opt_wsize:
                ctx->wsize = result.uint_32;
                break;
        case Opt_bsize:
                ctx->bsize = result.uint_32;
                break;
        case Opt_timeo:
                if (result.uint_32 < 1 || result.uint_32 > INT_MAX)
                        goto out_of_bounds;
                ctx->timeo = result.uint_32;
                break;
        case Opt_retrans:
                if (result.uint_32 > INT_MAX)
                        goto out_of_bounds;
                ctx->retrans = result.uint_32;
                break;
        case Opt_acregmin:
                ctx->acregmin = result.uint_32;
                break;
        case Opt_acregmax:
                ctx->acregmax = result.uint_32;
                break;
        case Opt_acdirmin:
                ctx->acdirmin = result.uint_32;
                break;
        case Opt_acdirmax:
                ctx->acdirmax = result.uint_32;
                break;
        case Opt_actimeo:
                ctx->acregmin = result.uint_32;
                ctx->acregmax = result.uint_32;
                ctx->acdirmin = result.uint_32;
                ctx->acdirmax = result.uint_32;
                break;
        case Opt_namelen:
                ctx->namlen = result.uint_32;
                break;
        case Opt_mountport:
                if (result.uint_32 > USHRT_MAX)
                        goto out_of_bounds;
                ctx->mount_server.port = result.uint_32;
                break;
        case Opt_mountvers:
                if (result.uint_32 < NFS_MNT_VERSION ||
                    result.uint_32 > NFS_MNT3_VERSION)
                        goto out_of_bounds;
                ctx->mount_server.version = result.uint_32;
                break;
        case Opt_minorversion:
                if (result.uint_32 < NFS4_MIN_MINOR_VERSION ||
                    result.uint_32 > NFS4_MAX_MINOR_VERSION)
                        goto out_of_bounds;
                ctx->minorversion = result.uint_32;
                break;

                /*
                 * options that take text values
                 */
        case Opt_v:
                ret = nfs_parse_version_string(fc, param->key + 1);
                if (ret < 0)
                        return ret;
                break;
        case Opt_vers:
                if (!param->string)
                        goto out_invalid_value;
                trace_nfs_mount_assign(param->key, param->string);
                ret = nfs_parse_version_string(fc, param->string);
                if (ret < 0)
                        return ret;
                break;
        case Opt_sec:
                ret = nfs_parse_security_flavors(fc, param);
                if (ret < 0)
                        return ret;
                break;
        case Opt_xprtsec:
                ret = nfs_parse_xprtsec_policy(fc, param);
                if (ret < 0)
                        return ret;
                break;
        case Opt_cert_serial:
                ret = nfs_tls_key_verify(result.int_32);
                if (ret < 0)
                        return ret;
                ctx->xprtsec.cert_serial = result.int_32;
                break;
        case Opt_privkey_serial:
                ret = nfs_tls_key_verify(result.int_32);
                if (ret < 0)
                        return ret;
                ctx->xprtsec.privkey_serial = result.int_32;
                break;

        case Opt_proto:
                if (!param->string)
                        goto out_invalid_value;
                trace_nfs_mount_assign(param->key, param->string);
                protofamily = AF_INET;
                switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
                case Opt_xprt_udp6:
                        protofamily = AF_INET6;
                        fallthrough;
                case Opt_xprt_udp:
                        ctx->flags &= ~NFS_MOUNT_TCP;
                        ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
                        break;
                case Opt_xprt_tcp6:
                        protofamily = AF_INET6;
                        fallthrough;
                case Opt_xprt_tcp:
                        ctx->flags |= NFS_MOUNT_TCP;
                        ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
                        break;
                case Opt_xprt_rdma6:
                        protofamily = AF_INET6;
                        fallthrough;
                case Opt_xprt_rdma:
                        /* vector side protocols to TCP */
                        ctx->flags |= NFS_MOUNT_TCP;
                        ret = xprt_find_transport_ident(param->string);
                        if (ret < 0)
                                goto out_bad_transport;
                        ctx->nfs_server.protocol = ret;
                        break;
                default:
                        goto out_bad_transport;
                }

                ctx->protofamily = protofamily;
                break;

        case Opt_mountproto:
                if (!param->string)
                        goto out_invalid_value;
                trace_nfs_mount_assign(param->key, param->string);
                mountfamily = AF_INET;
                switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
                case Opt_xprt_udp6:
                        mountfamily = AF_INET6;
                        fallthrough;
                case Opt_xprt_udp:
                        ctx->mount_server.protocol = XPRT_TRANSPORT_UDP;
                        break;
                case Opt_xprt_tcp6:
                        mountfamily = AF_INET6;
                        fallthrough;
                case Opt_xprt_tcp:
                        ctx->mount_server.protocol = XPRT_TRANSPORT_TCP;
                        break;
                case Opt_xprt_rdma: /* not used for side protocols */
                default:
                        goto out_bad_transport;
                }
                ctx->mountfamily = mountfamily;
                break;

        case Opt_addr:
                trace_nfs_mount_assign(param->key, param->string);
                len = rpc_pton(fc->net_ns, param->string, param->size,
                               &ctx->nfs_server.address,
                               sizeof(ctx->nfs_server._address));
                if (len == 0)
                        goto out_invalid_address;
                ctx->nfs_server.addrlen = len;
                break;
        case Opt_clientaddr:
                trace_nfs_mount_assign(param->key, param->string);
                kfree(ctx->client_address);
                ctx->client_address = param->string;
                param->string = NULL;
                break;
        case Opt_mounthost:
                trace_nfs_mount_assign(param->key, param->string);
                kfree(ctx->mount_server.hostname);
                ctx->mount_server.hostname = param->string;
                param->string = NULL;
                break;
        case Opt_mountaddr:
                trace_nfs_mount_assign(param->key, param->string);
                len = rpc_pton(fc->net_ns, param->string, param->size,
                               &ctx->mount_server.address,
                               sizeof(ctx->mount_server._address));
                if (len == 0)
                        goto out_invalid_address;
                ctx->mount_server.addrlen = len;
                break;
        case Opt_nconnect:
                trace_nfs_mount_assign(param->key, param->string);
                if (result.uint_32 < 1 || result.uint_32 > NFS_MAX_CONNECTIONS)
                        goto out_of_bounds;
                ctx->nfs_server.nconnect = result.uint_32;
                break;
        case Opt_max_connect:
                trace_nfs_mount_assign(param->key, param->string);
                if (result.uint_32 < 1 || result.uint_32 > NFS_MAX_TRANSPORTS)
                        goto out_of_bounds;
                ctx->nfs_server.max_connect = result.uint_32;
                break;
        case Opt_fatal_neterrors:
                trace_nfs_mount_assign(param->key, param->string);
                switch (result.uint_32) {
                case Opt_fatal_neterrors_default:
                        if (fc->net_ns != &init_net)
                                ctx->flags |= NFS_MOUNT_NETUNREACH_FATAL;
                        else
                                ctx->flags &= ~NFS_MOUNT_NETUNREACH_FATAL;
                        break;
                case Opt_fatal_neterrors_enetunreach:
                        ctx->flags |= NFS_MOUNT_NETUNREACH_FATAL;
                        break;
                case Opt_fatal_neterrors_none:
                        ctx->flags &= ~NFS_MOUNT_NETUNREACH_FATAL;
                        break;
                default:
                        goto out_invalid_value;
                }
                break;
        case Opt_lookupcache:
                trace_nfs_mount_assign(param->key, param->string);
                switch (result.uint_32) {
                case Opt_lookupcache_all:
                        ctx->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
                        break;
                case Opt_lookupcache_positive:
                        ctx->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
                        ctx->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
                        break;
                case Opt_lookupcache_none:
                        ctx->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
                        break;
                default:
                        goto out_invalid_value;
                }
                break;
        case Opt_local_lock:
                trace_nfs_mount_assign(param->key, param->string);
                switch (result.uint_32) {
                case Opt_local_lock_all:
                        ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK |
                                       NFS_MOUNT_LOCAL_FCNTL);
                        break;
                case Opt_local_lock_flock:
                        ctx->flags |= NFS_MOUNT_LOCAL_FLOCK;
                        break;
                case Opt_local_lock_posix:
                        ctx->flags |= NFS_MOUNT_LOCAL_FCNTL;
                        break;
                case Opt_local_lock_none:
                        ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
                                        NFS_MOUNT_LOCAL_FCNTL);
                        break;
                default:
                        goto out_invalid_value;
                }
                break;
        case Opt_write:
                trace_nfs_mount_assign(param->key, param->string);
                switch (result.uint_32) {
                case Opt_write_lazy:
                        ctx->flags &=
                                ~(NFS_MOUNT_WRITE_EAGER | NFS_MOUNT_WRITE_WAIT);
                        break;
                case Opt_write_eager:
                        ctx->flags |= NFS_MOUNT_WRITE_EAGER;
                        ctx->flags &= ~NFS_MOUNT_WRITE_WAIT;
                        break;
                case Opt_write_wait:
                        ctx->flags |=
                                NFS_MOUNT_WRITE_EAGER | NFS_MOUNT_WRITE_WAIT;
                        break;
                default:
                        goto out_invalid_value;
                }
                break;

                /*
                 * Special options
                 */
        case Opt_sloppy:
                ctx->sloppy = true;
                break;
        }

        return 0;

out_invalid_value:
        return nfs_invalf(fc, "NFS: Bad mount option value specified");
out_invalid_address:
        return nfs_invalf(fc, "NFS: Bad IP address specified");
out_of_bounds:
        return nfs_invalf(fc, "NFS: Value for '%s' out of range", param->key);
out_bad_transport:
        return nfs_invalf(fc, "NFS: Unrecognized transport protocol");
}

/*
 * Split fc->source into "hostname:export_path".
 *
 * The leftmost colon demarks the split between the server's hostname
 * and the export path.  If the hostname starts with a left square
 * bracket, then it may contain colons.
 *
 * Note: caller frees hostname and export path, even on error.
 */
static int nfs_parse_source(struct fs_context *fc,
                            size_t maxnamlen, size_t maxpathlen)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        const char *dev_name = fc->source;
        size_t len;
        const char *end;

        if (unlikely(!dev_name || !*dev_name))
                return -EINVAL;

        /* Is the host name protected with square brakcets? */
        if (*dev_name == '[') {
                end = strchr(++dev_name, ']');
                if (end == NULL || end[1] != ':')
                        goto out_bad_devname;

                len = end - dev_name;
                end++;
        } else {
                const char *comma;

                end = strchr(dev_name, ':');
                if (end == NULL)
                        goto out_bad_devname;
                len = end - dev_name;

                /* kill possible hostname list: not supported */
                comma = memchr(dev_name, ',', len);
                if (comma)
                        len = comma - dev_name;
        }

        if (len > maxnamlen)
                goto out_hostname;

        kfree(ctx->nfs_server.hostname);

        /* N.B. caller will free nfs_server.hostname in all cases */
        ctx->nfs_server.hostname = kmemdup_nul(dev_name, len, GFP_KERNEL);
        if (!ctx->nfs_server.hostname)
                goto out_nomem;
        len = strlen(++end);
        if (len > maxpathlen)
                goto out_path;
        ctx->nfs_server.export_path = kmemdup_nul(end, len, GFP_KERNEL);
        if (!ctx->nfs_server.export_path)
                goto out_nomem;

        trace_nfs_mount_path(ctx->nfs_server.export_path);
        return 0;

out_bad_devname:
        return nfs_invalf(fc, "NFS: device name not in host:path format");
out_nomem:
        nfs_errorf(fc, "NFS: not enough memory to parse device name");
        return -ENOMEM;
out_hostname:
        nfs_errorf(fc, "NFS: server hostname too long");
        return -ENAMETOOLONG;
out_path:
        nfs_errorf(fc, "NFS: export pathname too long");
        return -ENAMETOOLONG;
}

static inline bool is_remount_fc(struct fs_context *fc)
{
        return fc->root != NULL;
}

/*
 * Parse monolithic NFS2/NFS3 mount data
 * - fills in the mount root filehandle
 *
 * For option strings, user space handles the following behaviors:
 *
 * + DNS: mapping server host name to IP address ("addr=" option)
 *
 * + failure mode: how to behave if a mount request can't be handled
 *   immediately ("fg/bg" option)
 *
 * + retry: how often to retry a mount request ("retry=" option)
 *
 * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
 *   mountproto=tcp after mountproto=udp, and so on
 */
static int nfs23_parse_monolithic(struct fs_context *fc,
                                  struct nfs_mount_data *data)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        struct nfs_fh *mntfh = ctx->mntfh;
        struct sockaddr_storage *sap = &ctx->nfs_server._address;
        int extra_flags = NFS_MOUNT_LEGACY_INTERFACE;
        int ret;

        if (data == NULL)
                goto out_no_data;

        ctx->version = NFS_DEFAULT_VERSION;
        switch (data->version) {
        case 1:
                data->namlen = 0;
                fallthrough;
        case 2:
                data->bsize = 0;
                fallthrough;
        case 3:
                if (data->flags & NFS_MOUNT_VER3)
                        goto out_no_v3;
                data->root.size = NFS2_FHSIZE;
                memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
                /* Turn off security negotiation */
                extra_flags |= NFS_MOUNT_SECFLAVOUR;
                fallthrough;
        case 4:
                if (data->flags & NFS_MOUNT_SECFLAVOUR)
                        goto out_no_sec;
                fallthrough;
        case 5:
                memset(data->context, 0, sizeof(data->context));
                fallthrough;
        case 6:
                if (data->flags & NFS_MOUNT_VER3) {
                        if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
                                goto out_invalid_fh;
                        mntfh->size = data->root.size;
                        ctx->version = 3;
                } else {
                        mntfh->size = NFS2_FHSIZE;
                        ctx->version = 2;
                }


                memcpy(mntfh->data, data->root.data, mntfh->size);
                if (mntfh->size < sizeof(mntfh->data))
                        memset(mntfh->data + mntfh->size, 0,
                               sizeof(mntfh->data) - mntfh->size);

                /*
                 * for proto == XPRT_TRANSPORT_UDP, which is what uses
                 * to_exponential, implying shift: limit the shift value
                 * to BITS_PER_LONG (majortimeo is unsigned long)
                 */
                if (!(data->flags & NFS_MOUNT_TCP)) /* this will be UDP */
                        if (data->retrans >= 64) /* shift value is too large */
                                goto out_invalid_data;

                /*
                 * Translate to nfs_fs_context, which nfs_fill_super
                 * can deal with.
                 */
                ctx->flags      = data->flags & NFS_MOUNT_FLAGMASK;
                ctx->flags      |= extra_flags;
                ctx->rsize      = data->rsize;
                ctx->wsize      = data->wsize;
                ctx->timeo      = data->timeo;
                ctx->retrans    = data->retrans;
                ctx->acregmin   = data->acregmin;
                ctx->acregmax   = data->acregmax;
                ctx->acdirmin   = data->acdirmin;
                ctx->acdirmax   = data->acdirmax;
                ctx->need_mount = false;

                if (!is_remount_fc(fc)) {
                        memcpy(sap, &data->addr, sizeof(data->addr));
                        ctx->nfs_server.addrlen = sizeof(data->addr);
                        ctx->nfs_server.port = ntohs(data->addr.sin_port);
                }

                if (sap->ss_family != AF_INET ||
                    !nfs_verify_server_address(sap))
                        goto out_no_address;

                if (!(data->flags & NFS_MOUNT_TCP))
                        ctx->nfs_server.protocol = XPRT_TRANSPORT_UDP;
                /* N.B. caller will free nfs_server.hostname in all cases */
                ctx->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
                if (!ctx->nfs_server.hostname)
                        goto out_nomem;

                ctx->namlen             = data->namlen;
                ctx->bsize              = data->bsize;

                if (data->flags & NFS_MOUNT_SECFLAVOUR)
                        ctx->selected_flavor = data->pseudoflavor;
                else
                        ctx->selected_flavor = RPC_AUTH_UNIX;

                if (!(data->flags & NFS_MOUNT_NONLM))
                        ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
                                         NFS_MOUNT_LOCAL_FCNTL);
                else
                        ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK|
                                        NFS_MOUNT_LOCAL_FCNTL);

                /*
                 * The legacy version 6 binary mount data from userspace has a
                 * field used only to transport selinux information into the
                 * kernel.  To continue to support that functionality we
                 * have a touch of selinux knowledge here in the NFS code. The
                 * userspace code converted context=blah to just blah so we are
                 * converting back to the full string selinux understands.
                 */
                if (data->context[0]){
#ifdef CONFIG_SECURITY_SELINUX
                        int ret;

                        data->context[NFS_MAX_CONTEXT_LEN] = '\0';
                        ret = vfs_parse_fs_string(fc, "context", data->context);
                        if (ret < 0)
                                return ret;
#else
                        return -EINVAL;
#endif
                }

                break;
        default:
                goto generic;
        }

        ret = nfs_validate_transport_protocol(fc, ctx);
        if (ret)
                return ret;

        ctx->skip_reconfig_option_check = true;
        return 0;

generic:
        return generic_parse_monolithic(fc, data);

out_no_data:
        if (is_remount_fc(fc)) {
                ctx->skip_reconfig_option_check = true;
                return 0;
        }
        return nfs_invalf(fc, "NFS: mount program didn't pass any mount data");

out_no_v3:
        return nfs_invalf(fc, "NFS: nfs_mount_data version does not support v3");

out_no_sec:
        return nfs_invalf(fc, "NFS: nfs_mount_data version supports only AUTH_SYS");

out_nomem:
        return -ENOMEM;

out_no_address:
        return nfs_invalf(fc, "NFS: mount program didn't pass remote address");

out_invalid_fh:
        return nfs_invalf(fc, "NFS: invalid root filehandle");

out_invalid_data:
        return nfs_invalf(fc, "NFS: invalid binary mount data");
}

#if IS_ENABLED(CONFIG_NFS_V4)
struct compat_nfs_string {
        compat_uint_t len;
        compat_uptr_t data;
};

static inline void compat_nfs_string(struct nfs_string *dst,
                                     struct compat_nfs_string *src)
{
        dst->data = compat_ptr(src->data);
        dst->len = src->len;
}

struct compat_nfs4_mount_data_v1 {
        compat_int_t version;
        compat_int_t flags;
        compat_int_t rsize;
        compat_int_t wsize;
        compat_int_t timeo;
        compat_int_t retrans;
        compat_int_t acregmin;
        compat_int_t acregmax;
        compat_int_t acdirmin;
        compat_int_t acdirmax;
        struct compat_nfs_string client_addr;
        struct compat_nfs_string mnt_path;
        struct compat_nfs_string hostname;
        compat_uint_t host_addrlen;
        compat_uptr_t host_addr;
        compat_int_t proto;
        compat_int_t auth_flavourlen;
        compat_uptr_t auth_flavours;
};

static void nfs4_compat_mount_data_conv(struct nfs4_mount_data *data)
{
        struct compat_nfs4_mount_data_v1 *compat =
                        (struct compat_nfs4_mount_data_v1 *)data;

        /* copy the fields backwards */
        data->auth_flavours = compat_ptr(compat->auth_flavours);
        data->auth_flavourlen = compat->auth_flavourlen;
        data->proto = compat->proto;
        data->host_addr = compat_ptr(compat->host_addr);
        data->host_addrlen = compat->host_addrlen;
        compat_nfs_string(&data->hostname, &compat->hostname);
        compat_nfs_string(&data->mnt_path, &compat->mnt_path);
        compat_nfs_string(&data->client_addr, &compat->client_addr);
        data->acdirmax = compat->acdirmax;
        data->acdirmin = compat->acdirmin;
        data->acregmax = compat->acregmax;
        data->acregmin = compat->acregmin;
        data->retrans = compat->retrans;
        data->timeo = compat->timeo;
        data->wsize = compat->wsize;
        data->rsize = compat->rsize;
        data->flags = compat->flags;
        data->version = compat->version;
}

/*
 * Validate NFSv4 mount options
 */
static int nfs4_parse_monolithic(struct fs_context *fc,
                                 struct nfs4_mount_data *data)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        struct sockaddr_storage *sap = &ctx->nfs_server._address;
        int ret;
        char *c;

        if (!data) {
                if (is_remount_fc(fc))
                        goto done;
                return nfs_invalf(fc,
                        "NFS4: mount program didn't pass any mount data");
        }

        ctx->version = 4;

        if (data->version != 1)
                return generic_parse_monolithic(fc, data);

        if (in_compat_syscall())
                nfs4_compat_mount_data_conv(data);

        if (data->host_addrlen > sizeof(ctx->nfs_server.address))
                goto out_no_address;
        if (data->host_addrlen == 0)
                goto out_no_address;
        ctx->nfs_server.addrlen = data->host_addrlen;
        if (copy_from_user(sap, data->host_addr, data->host_addrlen))
                return -EFAULT;
        if (!nfs_verify_server_address(sap))
                goto out_no_address;
        ctx->nfs_server.port = ntohs(((struct sockaddr_in *)sap)->sin_port);

        if (data->auth_flavourlen) {
                rpc_authflavor_t pseudoflavor;

                if (data->auth_flavourlen > 1)
                        goto out_inval_auth;
                if (copy_from_user(&pseudoflavor, data->auth_flavours,
                                   sizeof(pseudoflavor)))
                        return -EFAULT;
                ctx->selected_flavor = pseudoflavor;
        } else {
                ctx->selected_flavor = RPC_AUTH_UNIX;
        }

        c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
        if (IS_ERR(c))
                return PTR_ERR(c);
        ctx->nfs_server.hostname = c;

        c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
        if (IS_ERR(c))
                return PTR_ERR(c);
        ctx->nfs_server.export_path = c;
        trace_nfs_mount_path(c);

        c = strndup_user(data->client_addr.data, 16);
        if (IS_ERR(c))
                return PTR_ERR(c);
        ctx->client_address = c;

        /*
         * Translate to nfs_fs_context, which nfs_fill_super
         * can deal with.
         */

        ctx->flags      = data->flags & NFS4_MOUNT_FLAGMASK;
        ctx->rsize      = data->rsize;
        ctx->wsize      = data->wsize;
        ctx->timeo      = data->timeo;
        ctx->retrans    = data->retrans;
        ctx->acregmin   = data->acregmin;
        ctx->acregmax   = data->acregmax;
        ctx->acdirmin   = data->acdirmin;
        ctx->acdirmax   = data->acdirmax;
        ctx->nfs_server.protocol = data->proto;
        ret = nfs_validate_transport_protocol(fc, ctx);
        if (ret)
                return ret;
done:
        ctx->skip_reconfig_option_check = true;
        return 0;

out_inval_auth:
        return nfs_invalf(fc, "NFS4: Invalid number of RPC auth flavours %d",
                      data->auth_flavourlen);

out_no_address:
        return nfs_invalf(fc, "NFS4: mount program didn't pass remote address");
}
#endif

/*
 * Parse a monolithic block of data from sys_mount().
 */
static int nfs_fs_context_parse_monolithic(struct fs_context *fc,
                                           void *data)
{
        if (fc->fs_type == &nfs_fs_type)
                return nfs23_parse_monolithic(fc, data);

#if IS_ENABLED(CONFIG_NFS_V4)
        if (fc->fs_type == &nfs4_fs_type)
                return nfs4_parse_monolithic(fc, data);
#endif

        return nfs_invalf(fc, "NFS: Unsupported monolithic data version");
}

/*
 * Validate the preparsed information in the config.
 */
static int nfs_fs_context_validate(struct fs_context *fc)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        struct nfs_subversion *nfs_mod;
        struct sockaddr_storage *sap = &ctx->nfs_server._address;
        int max_namelen = PAGE_SIZE;
        int max_pathlen = NFS_MAXPATHLEN;
        int port = 0;
        int ret;

        if (!fc->source)
                goto out_no_device_name;

        /* Check for sanity first. */
        if (ctx->minorversion && ctx->version != 4)
                goto out_minorversion_mismatch;

        if (ctx->options & NFS_OPTION_MIGRATION &&
            (ctx->version != 4 || ctx->minorversion != 0))
                goto out_migration_misuse;

        /* Verify that any proto=/mountproto= options match the address
         * families in the addr=/mountaddr= options.
         */
        if (ctx->protofamily != AF_UNSPEC &&
            ctx->protofamily != ctx->nfs_server.address.sa_family)
                goto out_proto_mismatch;

        if (ctx->mountfamily != AF_UNSPEC) {
                if (ctx->mount_server.addrlen) {
                        if (ctx->mountfamily != ctx->mount_server.address.sa_family)
                                goto out_mountproto_mismatch;
                } else {
                        if (ctx->mountfamily != ctx->nfs_server.address.sa_family)
                                goto out_mountproto_mismatch;
                }
        }

        if (!nfs_verify_server_address(sap))
                goto out_no_address;

        ret = nfs_validate_transport_protocol(fc, ctx);
        if (ret)
                return ret;

        if (ctx->version == 4) {
                if (IS_ENABLED(CONFIG_NFS_V4)) {
                        if (ctx->nfs_server.protocol == XPRT_TRANSPORT_RDMA)
                                port = NFS_RDMA_PORT;
                        else
                                port = NFS_PORT;
                        max_namelen = NFS4_MAXNAMLEN;
                        max_pathlen = NFS4_MAXPATHLEN;
                        ctx->flags &= ~(NFS_MOUNT_NONLM | NFS_MOUNT_NOACL |
                                        NFS_MOUNT_VER3 | NFS_MOUNT_LOCAL_FLOCK |
                                        NFS_MOUNT_LOCAL_FCNTL);
                } else {
                        goto out_v4_not_compiled;
                }
        } else {
                nfs_set_mount_transport_protocol(ctx);
                if (ctx->nfs_server.protocol == XPRT_TRANSPORT_RDMA)
                        port = NFS_RDMA_PORT;
        }

        nfs_set_port(sap, &ctx->nfs_server.port, port);

        ret = nfs_parse_source(fc, max_namelen, max_pathlen);
        if (ret < 0)
                return ret;

        /* Load the NFS protocol module if we haven't done so yet */
        if (!ctx->nfs_mod) {
                nfs_mod = find_nfs_version(ctx->version);
                if (IS_ERR(nfs_mod)) {
                        ret = PTR_ERR(nfs_mod);
                        goto out_version_unavailable;
                }
                ctx->nfs_mod = nfs_mod;
        }

        /* Ensure the filesystem context has the correct fs_type */
        if (fc->fs_type != ctx->nfs_mod->nfs_fs) {
                module_put(fc->fs_type->owner);
                __module_get(ctx->nfs_mod->nfs_fs->owner);
                fc->fs_type = ctx->nfs_mod->nfs_fs;
        }
        return 0;

out_no_device_name:
        return nfs_invalf(fc, "NFS: Device name not specified");
out_v4_not_compiled:
        nfs_errorf(fc, "NFS: NFSv4 is not compiled into kernel");
        return -EPROTONOSUPPORT;
out_no_address:
        return nfs_invalf(fc, "NFS: mount program didn't pass remote address");
out_mountproto_mismatch:
        return nfs_invalf(fc, "NFS: Mount server address does not match mountproto= option");
out_proto_mismatch:
        return nfs_invalf(fc, "NFS: Server address does not match proto= option");
out_minorversion_mismatch:
        return nfs_invalf(fc, "NFS: Mount option vers=%u does not support minorversion=%u",
                          ctx->version, ctx->minorversion);
out_migration_misuse:
        return nfs_invalf(fc, "NFS: 'Migration' not supported for this NFS version");
out_version_unavailable:
        nfs_errorf(fc, "NFS: Version unavailable");
        return ret;
}

/*
 * Create an NFS superblock by the appropriate method.
 */
static int nfs_get_tree(struct fs_context *fc)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);
        int err = nfs_fs_context_validate(fc);

        if (err)
                return err;
        if (!ctx->internal)
                return ctx->nfs_mod->rpc_ops->try_get_tree(fc);
        else
                return nfs_get_tree_common(fc);
}

/*
 * Handle duplication of a configuration.  The caller copied *src into *sc, but
 * it can't deal with resource pointers in the filesystem context, so we have
 * to do that.  We need to clear pointers, copy data or get extra refs as
 * appropriate.
 */
static int nfs_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
{
        struct nfs_fs_context *src = nfs_fc2context(src_fc), *ctx;

        ctx = kmemdup(src, sizeof(struct nfs_fs_context), GFP_KERNEL);
        if (!ctx)
                return -ENOMEM;

        ctx->mntfh = nfs_alloc_fhandle();
        if (!ctx->mntfh) {
                kfree(ctx);
                return -ENOMEM;
        }
        nfs_copy_fh(ctx->mntfh, src->mntfh);

        get_nfs_version(ctx->nfs_mod);
        ctx->client_address             = NULL;
        ctx->mount_server.hostname      = NULL;
        ctx->nfs_server.export_path     = NULL;
        ctx->nfs_server.hostname        = NULL;
        ctx->fscache_uniq               = NULL;
        ctx->clone_data.fattr           = NULL;
        fc->fs_private = ctx;
        return 0;
}

static void nfs_fs_context_free(struct fs_context *fc)
{
        struct nfs_fs_context *ctx = nfs_fc2context(fc);

        if (ctx) {
                if (ctx->server)
                        nfs_free_server(ctx->server);
                if (ctx->nfs_mod)
                        put_nfs_version(ctx->nfs_mod);
                kfree(ctx->client_address);
                kfree(ctx->mount_server.hostname);
                kfree(ctx->nfs_server.export_path);
                kfree(ctx->nfs_server.hostname);
                kfree(ctx->fscache_uniq);
                nfs_free_fhandle(ctx->mntfh);
                nfs_free_fattr(ctx->clone_data.fattr);
                kfree(ctx);
        }
}

static const struct fs_context_operations nfs_fs_context_ops = {
        .free                   = nfs_fs_context_free,
        .dup                    = nfs_fs_context_dup,
        .parse_param            = nfs_fs_context_parse_param,
        .parse_monolithic       = nfs_fs_context_parse_monolithic,
        .get_tree               = nfs_get_tree,
        .reconfigure            = nfs_reconfigure,
};

/*
 * Prepare superblock configuration.  We use the namespaces attached to the
 * context.  This may be the current process's namespaces, or it may be a
 * container's namespaces.
 */
static int nfs_init_fs_context(struct fs_context *fc)
{
        struct nfs_fs_context *ctx;

        ctx = kzalloc_obj(struct nfs_fs_context);
        if (unlikely(!ctx))
                return -ENOMEM;

        ctx->mntfh = nfs_alloc_fhandle();
        if (unlikely(!ctx->mntfh)) {
                kfree(ctx);
                return -ENOMEM;
        }

        ctx->protofamily        = AF_UNSPEC;
        ctx->mountfamily        = AF_UNSPEC;
        ctx->mount_server.port  = NFS_UNSPEC_PORT;

        if (fc->root) {
                /* reconfigure, start with the current config */
                struct nfs_server *nfss = fc->root->d_sb->s_fs_info;
                struct net *net = nfss->nfs_client->cl_net;

                ctx->flags              = nfss->flags;
                ctx->rsize              = nfss->rsize;
                ctx->wsize              = nfss->wsize;
                ctx->retrans            = nfss->client->cl_timeout->to_retries;
                ctx->selected_flavor    = nfss->client->cl_auth->au_flavor;
                ctx->acregmin           = nfss->acregmin / HZ;
                ctx->acregmax           = nfss->acregmax / HZ;
                ctx->acdirmin           = nfss->acdirmin / HZ;
                ctx->acdirmax           = nfss->acdirmax / HZ;
                ctx->timeo              = 10U * nfss->client->cl_timeout->to_initval / HZ;
                ctx->nfs_server.port    = nfss->port;
                ctx->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
                ctx->version            = nfss->nfs_client->rpc_ops->version;
                ctx->minorversion       = nfss->nfs_client->cl_minorversion;

                memcpy(&ctx->nfs_server._address, &nfss->nfs_client->cl_addr,
                        ctx->nfs_server.addrlen);

                if (fc->net_ns != net) {
                        put_net(fc->net_ns);
                        fc->net_ns = get_net(net);
                }

                ctx->nfs_mod = nfss->nfs_client->cl_nfs_mod;
                get_nfs_version(ctx->nfs_mod);
        } else {
                /* defaults */
                ctx->timeo              = NFS_UNSPEC_TIMEO;
                ctx->retrans            = NFS_UNSPEC_RETRANS;
                ctx->acregmin           = NFS_DEF_ACREGMIN;
                ctx->acregmax           = NFS_DEF_ACREGMAX;
                ctx->acdirmin           = NFS_DEF_ACDIRMIN;
                ctx->acdirmax           = NFS_DEF_ACDIRMAX;
                ctx->nfs_server.port    = NFS_UNSPEC_PORT;
                ctx->nfs_server.protocol = XPRT_TRANSPORT_TCP;
                ctx->selected_flavor    = RPC_AUTH_MAXFLAVOR;
                ctx->minorversion       = 0;
                ctx->need_mount         = true;
                ctx->xprtsec.policy     = RPC_XPRTSEC_NONE;
                ctx->xprtsec.cert_serial        = TLS_NO_CERT;
                ctx->xprtsec.privkey_serial     = TLS_NO_PRIVKEY;

                if (fc->net_ns != &init_net)
                        ctx->flags |= NFS_MOUNT_NETUNREACH_FATAL;

                fc->s_iflags            |= SB_I_STABLE_WRITES;
        }
        fc->fs_private = ctx;
        fc->ops = &nfs_fs_context_ops;
        return 0;
}

struct file_system_type nfs_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "nfs",
        .init_fs_context        = nfs_init_fs_context,
        .parameters             = nfs_fs_parameters,
        .kill_sb                = nfs_kill_super,
        .fs_flags               = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};
MODULE_ALIAS_FS("nfs");
EXPORT_SYMBOL_GPL(nfs_fs_type);

#if IS_ENABLED(CONFIG_NFS_V4)
struct file_system_type nfs4_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "nfs4",
        .init_fs_context        = nfs_init_fs_context,
        .parameters             = nfs_fs_parameters,
        .kill_sb                = nfs_kill_super,
        .fs_flags               = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};
MODULE_ALIAS_FS("nfs4");
MODULE_ALIAS("nfs4");
EXPORT_SYMBOL_GPL(nfs4_fs_type);
#endif /* CONFIG_NFS_V4 */