nfsd: knfsd must use the container user namespace

Convert knfsd to use the user namespace of the container that started
the server processes.

Signed-off-by: Trond Myklebust <[e-mail]>
Signed-off-by: J. Bruce Fields <[e-mail]>

fs/nfsd/export.c

···
 		err = get_int(&mesg, &an_int);
 		if (err)
 			goto out3;
-		exp.ex_anon_uid= make_kuid(&init_user_ns, an_int);
+		exp.ex_anon_uid= make_kuid(current_user_ns(), an_int);
 
 		/* anon gid */
 		err = get_int(&mesg, &an_int);
 		if (err)
 			goto out3;
-		exp.ex_anon_gid= make_kgid(&init_user_ns, an_int);
+		exp.ex_anon_gid= make_kgid(current_user_ns(), an_int);
 
 		/* fsid */
 		err = get_int(&mesg, &an_int);
···
 static void exp_flags(struct seq_file *m, int flag, int fsid,
 		kuid_t anonu, kgid_t anong, struct nfsd4_fs_locations *fsloc)
 {
+	struct user_namespace *userns = m->file->f_cred->user_ns;
+
 	show_expflags(m, flag, NFSEXP_ALLFLAGS);
 	if (flag & NFSEXP_FSID)
 		seq_printf(m, ",fsid=%d", fsid);
-	if (!uid_eq(anonu, make_kuid(&init_user_ns, (uid_t)-2)) &&
-	    !uid_eq(anonu, make_kuid(&init_user_ns, 0x10000-2)))
-		seq_printf(m, ",anonuid=%u", from_kuid(&init_user_ns, anonu));
-	if (!gid_eq(anong, make_kgid(&init_user_ns, (gid_t)-2)) &&
-	    !gid_eq(anong, make_kgid(&init_user_ns, 0x10000-2)))
-		seq_printf(m, ",anongid=%u", from_kgid(&init_user_ns, anong));
+	if (!uid_eq(anonu, make_kuid(userns, (uid_t)-2)) &&
+	    !uid_eq(anonu, make_kuid(userns, 0x10000-2)))
+		seq_printf(m, ",anonuid=%u", from_kuid_munged(userns, anonu));
+	if (!gid_eq(anong, make_kgid(userns, (gid_t)-2)) &&
+	    !gid_eq(anong, make_kgid(userns, 0x10000-2)))
+		seq_printf(m, ",anongid=%u", from_kgid_munged(userns, anong));
 	if (fsloc && fsloc->locations_count > 0) {
 		char *loctype = (fsloc->migrated) ? "refer" : "replicas";
 		int i;

fs/nfsd/nfs3xdr.c

···
 }
 
 static __be32 *
-decode_sattr3(__be32 *p, struct iattr *iap)
+decode_sattr3(__be32 *p, struct iattr *iap, struct user_namespace *userns)
 {
 	u32	tmp;
 
···
 		iap->ia_mode = ntohl(*p++);
 	}
 	if (*p++) {
-		iap->ia_uid = make_kuid(&init_user_ns, ntohl(*p++));
+		iap->ia_uid = make_kuid(userns, ntohl(*p++));
 		if (uid_valid(iap->ia_uid))
 			iap->ia_valid |= ATTR_UID;
 	}
 	if (*p++) {
-		iap->ia_gid = make_kgid(&init_user_ns, ntohl(*p++));
+		iap->ia_gid = make_kgid(userns, ntohl(*p++));
 		if (gid_valid(iap->ia_gid))
 			iap->ia_valid |= ATTR_GID;
 	}
···
 encode_fattr3(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
 	      struct kstat *stat)
 {
+	struct user_namespace *userns = nfsd_user_namespace(rqstp);
 	struct timespec ts;
 	*p++ = htonl(nfs3_ftypes[(stat->mode & S_IFMT) >> 12]);
 	*p++ = htonl((u32) (stat->mode & S_IALLUGO));
 	*p++ = htonl((u32) stat->nlink);
-	*p++ = htonl((u32) from_kuid(&init_user_ns, stat->uid));
-	*p++ = htonl((u32) from_kgid(&init_user_ns, stat->gid));
+	*p++ = htonl((u32) from_kuid_munged(userns, stat->uid));
+	*p++ = htonl((u32) from_kgid_munged(userns, stat->gid));
 	if (S_ISLNK(stat->mode) && stat->size > NFS3_MAXPATHLEN) {
 		p = xdr_encode_hyper(p, (u64) NFS3_MAXPATHLEN);
 	} else {
···
 	p = decode_fh(p, &args->fh);
 	if (!p)
 		return 0;
-	p = decode_sattr3(p, &args->attrs);
+	p = decode_sattr3(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	if ((args->check_guard = ntohl(*p++)) != 0) { 
 		struct timespec time; 
···
 	switch (args->createmode = ntohl(*p++)) {
 	case NFS3_CREATE_UNCHECKED:
 	case NFS3_CREATE_GUARDED:
-		p = decode_sattr3(p, &args->attrs);
+		p = decode_sattr3(p, &args->attrs, nfsd_user_namespace(rqstp));
 		break;
 	case NFS3_CREATE_EXCLUSIVE:
 		args->verf = p;
···
 	if (!(p = decode_fh(p, &args->fh)) ||
 	    !(p = decode_filename(p, &args->name, &args->len)))
 		return 0;
-	p = decode_sattr3(p, &args->attrs);
+	p = decode_sattr3(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	return xdr_argsize_check(rqstp, p);
 }
···
 	if (!(p = decode_fh(p, &args->ffh)) ||
 	    !(p = decode_filename(p, &args->fname, &args->flen)))
 		return 0;
-	p = decode_sattr3(p, &args->attrs);
+	p = decode_sattr3(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	args->tlen = ntohl(*p++);
 
···
 
 	if (args->ftype == NF3BLK  || args->ftype == NF3CHR
 	 || args->ftype == NF3SOCK || args->ftype == NF3FIFO)
-		p = decode_sattr3(p, &args->attrs);
+		p = decode_sattr3(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	if (args->ftype == NF3BLK || args->ftype == NF3CHR) {
 		args->major = ntohl(*p++);

fs/nfsd/nfs4idmap.c

···
 		return nfserr_inval;
 
 	status = do_name_to_id(rqstp, IDMAP_TYPE_USER, name, namelen, &id);
-	*uid = make_kuid(&init_user_ns, id);
+	*uid = make_kuid(nfsd_user_namespace(rqstp), id);
 	if (!uid_valid(*uid))
 		status = nfserr_badowner;
 	return status;
···
 		return nfserr_inval;
 
 	status = do_name_to_id(rqstp, IDMAP_TYPE_GROUP, name, namelen, &id);
-	*gid = make_kgid(&init_user_ns, id);
+	*gid = make_kgid(nfsd_user_namespace(rqstp), id);
 	if (!gid_valid(*gid))
 		status = nfserr_badowner;
 	return status;
···
 __be32 nfsd4_encode_user(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 			 kuid_t uid)
 {
-	u32 id = from_kuid(&init_user_ns, uid);
+	u32 id = from_kuid_munged(nfsd_user_namespace(rqstp), uid);
 	return encode_name_from_id(xdr, rqstp, IDMAP_TYPE_USER, id);
 }
 
 __be32 nfsd4_encode_group(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 			  kgid_t gid)
 {
-	u32 id = from_kgid(&init_user_ns, gid);
+	u32 id = from_kgid_munged(nfsd_user_namespace(rqstp), gid);
 	return encode_name_from_id(xdr, rqstp, IDMAP_TYPE_GROUP, id);
 }

fs/nfsd/nfs4xdr.c

···
 static __be32 nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_cb_sec *cbs)
 {
 	DECODE_HEAD;
+	struct user_namespace *userns = nfsd_user_namespace(argp->rqstp);
 	u32 dummy, uid, gid;
 	char *machine_name;
 	int i;
···
 			dummy = be32_to_cpup(p++);
 			READ_BUF(dummy * 4);
 			if (cbs->flavor == (u32)(-1)) {
-				kuid_t kuid = make_kuid(&init_user_ns, uid);
-				kgid_t kgid = make_kgid(&init_user_ns, gid);
+				kuid_t kuid = make_kuid(userns, uid);
+				kgid_t kgid = make_kgid(userns, gid);
 				if (uid_valid(kuid) && gid_valid(kgid)) {
 					cbs->uid = kuid;
 					cbs->gid = kgid;

fs/nfsd/nfsd.h

···
 #include <linux/nfs3.h>
 #include <linux/nfs4.h>
 #include <linux/sunrpc/svc.h>
+#include <linux/sunrpc/svc_xprt.h>
 #include <linux/sunrpc/msg_prot.h>
 
 #include <uapi/linux/nfsd/debug.h>
···
 static inline int nfsd_v4client(struct svc_rqst *rq)
 {
 	return rq->rq_prog == NFS_PROGRAM && rq->rq_vers == 4;
+}
+static inline struct user_namespace *
+nfsd_user_namespace(const struct svc_rqst *rqstp)
+{
+	const struct cred *cred = rqstp->rq_xprt->xpt_cred;
+	return cred ? cred->user_ns : &init_user_ns;
 }
 
 /* 

fs/nfsd/nfsxdr.c

···
 }
 
 static __be32 *
-decode_sattr(__be32 *p, struct iattr *iap)
+decode_sattr(__be32 *p, struct iattr *iap, struct user_namespace *userns)
 {
 	u32	tmp, tmp1;
 
···
 		iap->ia_mode = tmp;
 	}
 	if ((tmp = ntohl(*p++)) != (u32)-1) {
-		iap->ia_uid = make_kuid(&init_user_ns, tmp);
+		iap->ia_uid = make_kuid(userns, tmp);
 		if (uid_valid(iap->ia_uid))
 			iap->ia_valid |= ATTR_UID;
 	}
 	if ((tmp = ntohl(*p++)) != (u32)-1) {
-		iap->ia_gid = make_kgid(&init_user_ns, tmp);
+		iap->ia_gid = make_kgid(userns, tmp);
 		if (gid_valid(iap->ia_gid))
 			iap->ia_valid |= ATTR_GID;
 	}
···
 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;
···
 	*p++ = htonl(nfs_ftypes[type >> 12]);
 	*p++ = htonl((u32) stat->mode);
 	*p++ = htonl((u32) stat->nlink);
-	*p++ = htonl((u32) from_kuid(&init_user_ns, stat->uid));
-	*p++ = htonl((u32) from_kgid(&init_user_ns, stat->gid));
+	*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);
···
 	p = decode_fh(p, &args->fh);
 	if (!p)
 		return 0;
-	p = decode_sattr(p, &args->attrs);
+	p = decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	return xdr_argsize_check(rqstp, p);
 }
···
 	if (   !(p = decode_fh(p, &args->fh))
 	    || !(p = decode_filename(p, &args->name, &args->len)))
 		return 0;
-	p = decode_sattr(p, &args->attrs);
+	p = decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	return xdr_argsize_check(rqstp, p);
 }
···
 			return 0;
 		p += xdrlen;
 	}
-	decode_sattr(p, &args->attrs);
+	decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
 
 	return 1;
 }