// SPDX-License-Identifier: GPL-2.0
/*
 * XDR support for nfsd
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#include "vfs.h"
#include "xdr.h"
#include "auth.h"

#define NFSDDBG_FACILITY                NFSDDBG_XDR

/*
 * Mapping of S_IF* types to NFS file types
 */
static u32      nfs_ftypes[] = {
        NFNON,  NFCHR,  NFCHR, NFBAD,
        NFDIR,  NFBAD,  NFBLK, NFBAD,
        NFREG,  NFBAD,  NFLNK, NFBAD,
        NFSOCK, NFBAD,  NFLNK, NFBAD,
};


/*
 * Basic NFSv2 data types (RFC 1094 Section 2.3)
 */

/**
 * svcxdr_decode_fhandle - Decode an NFSv2 file handle
 * @xdr: XDR stream positioned at an encoded NFSv2 FH
 * @fhp: OUT: filled-in server file handle
 *
 * Return values:
 *  %false: The encoded file handle was not valid
 *  %true: @fhp has been initialized
 */
bool
svcxdr_decode_fhandle(struct xdr_stream *xdr, struct svc_fh *fhp)
{
        __be32 *p;

        p = xdr_inline_decode(xdr, NFS_FHSIZE);
        if (!p)
                return false;
        fh_init(fhp, NFS_FHSIZE);
        memcpy(&fhp->fh_handle.fh_base, p, NFS_FHSIZE);
        fhp->fh_handle.fh_size = NFS_FHSIZE;

        return true;
}

static __be32 *
encode_fh(__be32 *p, struct svc_fh *fhp)
{
        memcpy(p, &fhp->fh_handle.fh_base, NFS_FHSIZE);
        return p + (NFS_FHSIZE>> 2);
}

static bool
svcxdr_decode_filename(struct xdr_stream *xdr, char **name, unsigned int *len)
{
        u32 size, i;
        __be32 *p;
        char *c;

        if (xdr_stream_decode_u32(xdr, &size) < 0)
                return false;
        if (size == 0 || size > NFS_MAXNAMLEN)
                return false;
        p = xdr_inline_decode(xdr, size);
        if (!p)
                return false;

        *len = size;
        *name = (char *)p;
        for (i = 0, c = *name; i < size; i++, c++)
                if (*c == '\0' || *c == '/')
                        return false;

        return true;
}

static bool
svcxdr_decode_diropargs(struct xdr_stream *xdr, struct svc_fh *fhp,
                        char **name, unsigned int *len)
{
        return svcxdr_decode_fhandle(xdr, fhp) &&
                svcxdr_decode_filename(xdr, name, len);
}

static bool
svcxdr_decode_sattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
                    struct iattr *iap)
{
        u32 tmp1, tmp2;
        __be32 *p;

        p = xdr_inline_decode(xdr, XDR_UNIT * 8);
        if (!p)
                return false;

        iap->ia_valid = 0;

        /*
         * Some Sun clients put 0xffff in the mode field when they
         * mean 0xffffffff.
         */
        tmp1 = be32_to_cpup(p++);
        if (tmp1 != (u32)-1 && tmp1 != 0xffff) {
                iap->ia_valid |= ATTR_MODE;
                iap->ia_mode = tmp1;
        }

        tmp1 = be32_to_cpup(p++);
        if (tmp1 != (u32)-1) {
                iap->ia_uid = make_kuid(nfsd_user_namespace(rqstp), tmp1);
                if (uid_valid(iap->ia_uid))
                        iap->ia_valid |= ATTR_UID;
        }

        tmp1 = be32_to_cpup(p++);
        if (tmp1 != (u32)-1) {
                iap->ia_gid = make_kgid(nfsd_user_namespace(rqstp), tmp1);
                if (gid_valid(iap->ia_gid))
                        iap->ia_valid |= ATTR_GID;
        }

        tmp1 = be32_to_cpup(p++);
        if (tmp1 != (u32)-1) {
                iap->ia_valid |= ATTR_SIZE;
                iap->ia_size = tmp1;
        }

        tmp1 = be32_to_cpup(p++);
        tmp2 = be32_to_cpup(p++);
        if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
                iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
                iap->ia_atime.tv_sec = tmp1;
                iap->ia_atime.tv_nsec = tmp2 * NSEC_PER_USEC;
        }

        tmp1 = be32_to_cpup(p++);
        tmp2 = be32_to_cpup(p++);
        if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
                iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
                iap->ia_mtime.tv_sec = tmp1;
                iap->ia_mtime.tv_nsec = tmp2 * NSEC_PER_USEC;
                /*
                 * Passing the invalid value useconds=1000000 for mtime
                 * is a Sun convention for "set both mtime and atime to
                 * current server time".  It's needed to make permissions
                 * checks for the "touch" program across v2 mounts to
                 * Solaris and Irix boxes work correctly. See description of
                 * sattr in section 6.1 of "NFS Illustrated" by
                 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
                 */
                if (tmp2 == 1000000)
                        iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
        }

        return true;
}

static __be32 *
encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
             struct kstat *stat)
{
        struct user_namespace *userns = nfsd_user_namespace(rqstp);
        struct dentry   *dentry = fhp->fh_dentry;
        int type;
        struct timespec64 time;
        u32 f;

        type = (stat->mode & S_IFMT);

        *p++ = htonl(nfs_ftypes[type >> 12]);
        *p++ = htonl((u32) stat->mode);
        *p++ = htonl((u32) stat->nlink);
        *p++ = htonl((u32) from_kuid_munged(userns, stat->uid));
        *p++ = htonl((u32) from_kgid_munged(userns, stat->gid));

        if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN) {
                *p++ = htonl(NFS_MAXPATHLEN);
        } else {
                *p++ = htonl((u32) stat->size);
        }
        *p++ = htonl((u32) stat->blksize);
        if (S_ISCHR(type) || S_ISBLK(type))
                *p++ = htonl(new_encode_dev(stat->rdev));
        else
                *p++ = htonl(0xffffffff);
        *p++ = htonl((u32) stat->blocks);
        switch (fsid_source(fhp)) {
        default:
        case FSIDSOURCE_DEV:
                *p++ = htonl(new_encode_dev(stat->dev));
                break;
        case FSIDSOURCE_FSID:
                *p++ = htonl((u32) fhp->fh_export->ex_fsid);
                break;
        case FSIDSOURCE_UUID:
                f = ((u32*)fhp->fh_export->ex_uuid)[0];
                f ^= ((u32*)fhp->fh_export->ex_uuid)[1];
                f ^= ((u32*)fhp->fh_export->ex_uuid)[2];
                f ^= ((u32*)fhp->fh_export->ex_uuid)[3];
                *p++ = htonl(f);
                break;
        }
        *p++ = htonl((u32) stat->ino);
        *p++ = htonl((u32) stat->atime.tv_sec);
        *p++ = htonl(stat->atime.tv_nsec ? stat->atime.tv_nsec / 1000 : 0);
        time = stat->mtime;
        lease_get_mtime(d_inode(dentry), &time); 
        *p++ = htonl((u32) time.tv_sec);
        *p++ = htonl(time.tv_nsec ? time.tv_nsec / 1000 : 0); 
        *p++ = htonl((u32) stat->ctime.tv_sec);
        *p++ = htonl(stat->ctime.tv_nsec ? stat->ctime.tv_nsec / 1000 : 0);

        return p;
}

/* Helper function for NFSv2 ACL code */
__be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp, struct kstat *stat)
{
        return encode_fattr(rqstp, p, fhp, stat);
}

/*
 * XDR decode functions
 */

int
nfssvc_decode_fhandleargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_fhandle *args = rqstp->rq_argp;

        return svcxdr_decode_fhandle(xdr, &args->fh);
}

int
nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_sattrargs *args = rqstp->rq_argp;

        return svcxdr_decode_fhandle(xdr, &args->fh) &&
                svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
}

int
nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_diropargs *args = rqstp->rq_argp;

        return svcxdr_decode_diropargs(xdr, &args->fh, &args->name, &args->len);
}

int
nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_readargs *args = rqstp->rq_argp;
        u32 totalcount;

        if (!svcxdr_decode_fhandle(xdr, &args->fh))
                return 0;
        if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
                return 0;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return 0;
        /* totalcount is ignored */
        if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
                return 0;

        return 1;
}

int
nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_writeargs *args = rqstp->rq_argp;
        struct kvec *head = rqstp->rq_arg.head;
        struct kvec *tail = rqstp->rq_arg.tail;
        u32 beginoffset, totalcount;
        size_t remaining;

        if (!svcxdr_decode_fhandle(xdr, &args->fh))
                return 0;
        /* beginoffset is ignored */
        if (xdr_stream_decode_u32(xdr, &beginoffset) < 0)
                return 0;
        if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
                return 0;
        /* totalcount is ignored */
        if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
                return 0;

        /* opaque data */
        if (xdr_stream_decode_u32(xdr, &args->len) < 0)
                return 0;
        if (args->len > NFSSVC_MAXBLKSIZE_V2)
                return 0;
        remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
        remaining -= xdr_stream_pos(xdr);
        if (remaining < xdr_align_size(args->len))
                return 0;
        args->first.iov_base = xdr->p;
        args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);

        return 1;
}

int
nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_createargs *args = rqstp->rq_argp;

        return svcxdr_decode_diropargs(xdr, &args->fh,
                                       &args->name, &args->len) &&
                svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
}

int
nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_renameargs *args = rqstp->rq_argp;

        return svcxdr_decode_diropargs(xdr, &args->ffh,
                                       &args->fname, &args->flen) &&
                svcxdr_decode_diropargs(xdr, &args->tfh,
                                        &args->tname, &args->tlen);
}

int
nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_linkargs *args = rqstp->rq_argp;

        return svcxdr_decode_fhandle(xdr, &args->ffh) &&
                svcxdr_decode_diropargs(xdr, &args->tfh,
                                        &args->tname, &args->tlen);
}

int
nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_symlinkargs *args = rqstp->rq_argp;
        struct kvec *head = rqstp->rq_arg.head;

        if (!svcxdr_decode_diropargs(xdr, &args->ffh, &args->fname, &args->flen))
                return 0;
        if (xdr_stream_decode_u32(xdr, &args->tlen) < 0)
                return 0;
        if (args->tlen == 0)
                return 0;

        args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
        args->first.iov_base = xdr_inline_decode(xdr, args->tlen);
        if (!args->first.iov_base)
                return 0;
        return svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
}

int
nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
{
        struct xdr_stream *xdr = &rqstp->rq_arg_stream;
        struct nfsd_readdirargs *args = rqstp->rq_argp;

        if (!svcxdr_decode_fhandle(xdr, &args->fh))
                return 0;
        if (xdr_stream_decode_u32(xdr, &args->cookie) < 0)
                return 0;
        if (xdr_stream_decode_u32(xdr, &args->count) < 0)
                return 0;

        return 1;
}

/*
 * XDR encode functions
 */

int
nfssvc_encode_stat(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_stat *resp = rqstp->rq_resp;

        *p++ = resp->status;
        return xdr_ressize_check(rqstp, p);
}

int
nfssvc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_attrstat *resp = rqstp->rq_resp;

        *p++ = resp->status;
        if (resp->status != nfs_ok)
                goto out;
        p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
out:
        return xdr_ressize_check(rqstp, p);
}

int
nfssvc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_diropres *resp = rqstp->rq_resp;

        *p++ = resp->status;
        if (resp->status != nfs_ok)
                goto out;
        p = encode_fh(p, &resp->fh);
        p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
out:
        return xdr_ressize_check(rqstp, p);
}

int
nfssvc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_readlinkres *resp = rqstp->rq_resp;
        struct kvec *head = rqstp->rq_res.head;

        *p++ = resp->status;
        if (resp->status != nfs_ok)
                return xdr_ressize_check(rqstp, p);

        *p++ = htonl(resp->len);
        xdr_ressize_check(rqstp, p);
        rqstp->rq_res.page_len = resp->len;
        if (resp->len & 3) {
                /* need to pad the tail */
                rqstp->rq_res.tail[0].iov_base = p;
                *p = 0;
                rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
        }
        if (svc_encode_result_payload(rqstp, head->iov_len, resp->len))
                return 0;
        return 1;
}

int
nfssvc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_readres *resp = rqstp->rq_resp;
        struct kvec *head = rqstp->rq_res.head;

        *p++ = resp->status;
        if (resp->status != nfs_ok)
                return xdr_ressize_check(rqstp, p);

        p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
        *p++ = htonl(resp->count);
        xdr_ressize_check(rqstp, p);

        /* now update rqstp->rq_res to reflect data as well */
        rqstp->rq_res.page_len = resp->count;
        if (resp->count & 3) {
                /* need to pad the tail */
                rqstp->rq_res.tail[0].iov_base = p;
                *p = 0;
                rqstp->rq_res.tail[0].iov_len = 4 - (resp->count&3);
        }
        if (svc_encode_result_payload(rqstp, head->iov_len, resp->count))
                return 0;
        return 1;
}

int
nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_readdirres *resp = rqstp->rq_resp;

        *p++ = resp->status;
        if (resp->status != nfs_ok)
                return xdr_ressize_check(rqstp, p);

        xdr_ressize_check(rqstp, p);
        p = resp->buffer;
        *p++ = 0;                       /* no more entries */
        *p++ = htonl((resp->common.err == nfserr_eof));
        rqstp->rq_res.page_len = (((unsigned long)p-1) & ~PAGE_MASK)+1;

        return 1;
}

int
nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
{
        struct nfsd_statfsres *resp = rqstp->rq_resp;
        struct kstatfs  *stat = &resp->stats;

        *p++ = resp->status;
        if (resp->status != nfs_ok)
                return xdr_ressize_check(rqstp, p);

        *p++ = htonl(NFSSVC_MAXBLKSIZE_V2);     /* max transfer size */
        *p++ = htonl(stat->f_bsize);
        *p++ = htonl(stat->f_blocks);
        *p++ = htonl(stat->f_bfree);
        *p++ = htonl(stat->f_bavail);
        return xdr_ressize_check(rqstp, p);
}

int
nfssvc_encode_entry(void *ccdv, const char *name,
                    int namlen, loff_t offset, u64 ino, unsigned int d_type)
{
        struct readdir_cd *ccd = ccdv;
        struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
        __be32  *p = cd->buffer;
        int     buflen, slen;

        /*
        dprintk("nfsd: entry(%.*s off %ld ino %ld)\n",
                        namlen, name, offset, ino);
         */

        if (offset > ~((u32) 0)) {
                cd->common.err = nfserr_fbig;
                return -EINVAL;
        }
        if (cd->offset)
                *cd->offset = htonl(offset);

        /* truncate filename */
        namlen = min(namlen, NFS2_MAXNAMLEN);
        slen = XDR_QUADLEN(namlen);

        if ((buflen = cd->buflen - slen - 4) < 0) {
                cd->common.err = nfserr_toosmall;
                return -EINVAL;
        }
        if (ino > ~((u32) 0)) {
                cd->common.err = nfserr_fbig;
                return -EINVAL;
        }
        *p++ = xdr_one;                         /* mark entry present */
        *p++ = htonl((u32) ino);                /* file id */
        p    = xdr_encode_array(p, name, namlen);/* name length & name */
        cd->offset = p;                 /* remember pointer */
        *p++ = htonl(~0U);              /* offset of next entry */

        cd->buflen = buflen;
        cd->buffer = p;
        cd->common.err = nfs_ok;
        return 0;
}

/*
 * XDR release functions
 */
void nfssvc_release_attrstat(struct svc_rqst *rqstp)
{
        struct nfsd_attrstat *resp = rqstp->rq_resp;

        fh_put(&resp->fh);
}

void nfssvc_release_diropres(struct svc_rqst *rqstp)
{
        struct nfsd_diropres *resp = rqstp->rq_resp;

        fh_put(&resp->fh);
}

void nfssvc_release_readres(struct svc_rqst *rqstp)
{
        struct nfsd_readres *resp = rqstp->rq_resp;

        fh_put(&resp->fh);
}