v4.19.13 snapshot.
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
new file mode 100644
index 0000000..24f06dc
--- /dev/null
+++ b/fs/nfs/nfs4namespace.c
@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/nfs/nfs4namespace.c
+ *
+ * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
+ * - Modified by David Howells <dhowells@redhat.com>
+ *
+ * NFSv4 namespace
+ */
+
+#include <linux/dcache.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include "internal.h"
+#include "nfs4_fs.h"
+#include "dns_resolve.h"
+
+#define NFSDBG_FACILITY NFSDBG_VFS
+
+/*
+ * Convert the NFSv4 pathname components into a standard posix path.
+ *
+ * Note that the resulting string will be placed at the end of the buffer
+ */
+static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
+ char *buffer, ssize_t buflen)
+{
+ char *end = buffer + buflen;
+ int n;
+
+ *--end = '\0';
+ buflen--;
+
+ n = pathname->ncomponents;
+ while (--n >= 0) {
+ const struct nfs4_string *component = &pathname->components[n];
+ buflen -= component->len + 1;
+ if (buflen < 0)
+ goto Elong;
+ end -= component->len;
+ memcpy(end, component->data, component->len);
+ *--end = '/';
+ }
+ return end;
+Elong:
+ return ERR_PTR(-ENAMETOOLONG);
+}
+
+/*
+ * return the path component of "<server>:<path>"
+ * nfspath - the "<server>:<path>" string
+ * end - one past the last char that could contain "<server>:"
+ * returns NULL on failure
+ */
+static char *nfs_path_component(const char *nfspath, const char *end)
+{
+ char *p;
+
+ if (*nfspath == '[') {
+ /* parse [] escaped IPv6 addrs */
+ p = strchr(nfspath, ']');
+ if (p != NULL && ++p < end && *p == ':')
+ return p + 1;
+ } else {
+ /* otherwise split on first colon */
+ p = strchr(nfspath, ':');
+ if (p != NULL && p < end)
+ return p + 1;
+ }
+ return NULL;
+}
+
+/*
+ * Determine the mount path as a string
+ */
+static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
+{
+ char *limit;
+ char *path = nfs_path(&limit, dentry, buffer, buflen,
+ NFS_PATH_CANONICAL);
+ if (!IS_ERR(path)) {
+ char *path_component = nfs_path_component(path, limit);
+ if (path_component)
+ return path_component;
+ }
+ return path;
+}
+
+/*
+ * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
+ * believe to be the server path to this dentry
+ */
+static int nfs4_validate_fspath(struct dentry *dentry,
+ const struct nfs4_fs_locations *locations,
+ char *page, char *page2)
+{
+ const char *path, *fs_path;
+
+ path = nfs4_path(dentry, page, PAGE_SIZE);
+ if (IS_ERR(path))
+ return PTR_ERR(path);
+
+ fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
+ if (IS_ERR(fs_path))
+ return PTR_ERR(fs_path);
+
+ if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
+ dprintk("%s: path %s does not begin with fsroot %s\n",
+ __func__, path, fs_path);
+ return -ENOENT;
+ }
+
+ return 0;
+}
+
+static size_t nfs_parse_server_name(char *string, size_t len,
+ struct sockaddr *sa, size_t salen, struct net *net)
+{
+ ssize_t ret;
+
+ ret = rpc_pton(net, string, len, sa, salen);
+ if (ret == 0) {
+ ret = nfs_dns_resolve_name(net, string, len, sa, salen);
+ if (ret < 0)
+ ret = 0;
+ }
+ return ret;
+}
+
+/**
+ * nfs_find_best_sec - Find a security mechanism supported locally
+ * @server: NFS server struct
+ * @flavors: List of security tuples returned by SECINFO procedure
+ *
+ * Return an rpc client that uses the first security mechanism in
+ * "flavors" that is locally supported. The "flavors" array
+ * is searched in the order returned from the server, per RFC 3530
+ * recommendation and each flavor is checked for membership in the
+ * sec= mount option list if it exists.
+ *
+ * Return -EPERM if no matching flavor is found in the array.
+ *
+ * Please call rpc_shutdown_client() when you are done with this rpc client.
+ *
+ */
+static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
+ struct nfs_server *server,
+ struct nfs4_secinfo_flavors *flavors)
+{
+ rpc_authflavor_t pflavor;
+ struct nfs4_secinfo4 *secinfo;
+ unsigned int i;
+
+ for (i = 0; i < flavors->num_flavors; i++) {
+ secinfo = &flavors->flavors[i];
+
+ switch (secinfo->flavor) {
+ case RPC_AUTH_NULL:
+ case RPC_AUTH_UNIX:
+ case RPC_AUTH_GSS:
+ pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
+ &secinfo->flavor_info);
+ /* does the pseudoflavor match a sec= mount opt? */
+ if (pflavor != RPC_AUTH_MAXFLAVOR &&
+ nfs_auth_info_match(&server->auth_info, pflavor)) {
+ struct rpc_clnt *new;
+ struct rpc_cred *cred;
+
+ /* Cloning creates an rpc_auth for the flavor */
+ new = rpc_clone_client_set_auth(clnt, pflavor);
+ if (IS_ERR(new))
+ continue;
+ /**
+ * Check that the user actually can use the
+ * flavor. This is mostly for RPC_AUTH_GSS
+ * where cr_init obtains a gss context
+ */
+ cred = rpcauth_lookupcred(new->cl_auth, 0);
+ if (IS_ERR(cred)) {
+ rpc_shutdown_client(new);
+ continue;
+ }
+ put_rpccred(cred);
+ return new;
+ }
+ }
+ }
+ return ERR_PTR(-EPERM);
+}
+
+/**
+ * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
+ * return an rpc_clnt that uses the best available security flavor with
+ * respect to the secinfo flavor list and the sec= mount options.
+ *
+ * @clnt: RPC client to clone
+ * @inode: directory inode
+ * @name: lookup name
+ *
+ * Please call rpc_shutdown_client() when you are done with this rpc client.
+ */
+struct rpc_clnt *
+nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
+ const struct qstr *name)
+{
+ struct page *page;
+ struct nfs4_secinfo_flavors *flavors;
+ struct rpc_clnt *new;
+ int err;
+
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return ERR_PTR(-ENOMEM);
+
+ flavors = page_address(page);
+
+ err = nfs4_proc_secinfo(inode, name, flavors);
+ if (err < 0) {
+ new = ERR_PTR(err);
+ goto out;
+ }
+
+ new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
+
+out:
+ put_page(page);
+ return new;
+}
+
+static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
+ char *page, char *page2,
+ const struct nfs4_fs_location *location)
+{
+ const size_t addr_bufsize = sizeof(struct sockaddr_storage);
+ struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
+ struct vfsmount *mnt = ERR_PTR(-ENOENT);
+ char *mnt_path;
+ unsigned int maxbuflen;
+ unsigned int s;
+
+ mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
+ if (IS_ERR(mnt_path))
+ return ERR_CAST(mnt_path);
+ mountdata->mnt_path = mnt_path;
+ maxbuflen = mnt_path - 1 - page2;
+
+ mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
+ if (mountdata->addr == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ for (s = 0; s < location->nservers; s++) {
+ const struct nfs4_string *buf = &location->servers[s];
+
+ if (buf->len <= 0 || buf->len >= maxbuflen)
+ continue;
+
+ if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
+ continue;
+
+ mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
+ mountdata->addr, addr_bufsize, net);
+ if (mountdata->addrlen == 0)
+ continue;
+
+ memcpy(page2, buf->data, buf->len);
+ page2[buf->len] = '\0';
+ mountdata->hostname = page2;
+
+ snprintf(page, PAGE_SIZE, "%s:%s",
+ mountdata->hostname,
+ mountdata->mnt_path);
+
+ mnt = vfs_submount(mountdata->dentry, &nfs4_referral_fs_type, page, mountdata);
+ if (!IS_ERR(mnt))
+ break;
+ }
+ kfree(mountdata->addr);
+ return mnt;
+}
+
+/**
+ * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
+ * @dentry - parent directory
+ * @locations - array of NFSv4 server location information
+ *
+ */
+static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
+ const struct nfs4_fs_locations *locations)
+{
+ struct vfsmount *mnt = ERR_PTR(-ENOENT);
+ struct nfs_clone_mount mountdata = {
+ .sb = dentry->d_sb,
+ .dentry = dentry,
+ .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
+ };
+ char *page = NULL, *page2 = NULL;
+ int loc, error;
+
+ if (locations == NULL || locations->nlocations <= 0)
+ goto out;
+
+ dprintk("%s: referral at %pd2\n", __func__, dentry);
+
+ page = (char *) __get_free_page(GFP_USER);
+ if (!page)
+ goto out;
+
+ page2 = (char *) __get_free_page(GFP_USER);
+ if (!page2)
+ goto out;
+
+ /* Ensure fs path is a prefix of current dentry path */
+ error = nfs4_validate_fspath(dentry, locations, page, page2);
+ if (error < 0) {
+ mnt = ERR_PTR(error);
+ goto out;
+ }
+
+ for (loc = 0; loc < locations->nlocations; loc++) {
+ const struct nfs4_fs_location *location = &locations->locations[loc];
+
+ if (location == NULL || location->nservers <= 0 ||
+ location->rootpath.ncomponents == 0)
+ continue;
+
+ mnt = try_location(&mountdata, page, page2, location);
+ if (!IS_ERR(mnt))
+ break;
+ }
+
+out:
+ free_page((unsigned long) page);
+ free_page((unsigned long) page2);
+ return mnt;
+}
+
+/*
+ * nfs_do_refmount - handle crossing a referral on server
+ * @dentry - dentry of referral
+ *
+ */
+static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
+{
+ struct vfsmount *mnt = ERR_PTR(-ENOMEM);
+ struct dentry *parent;
+ struct nfs4_fs_locations *fs_locations = NULL;
+ struct page *page;
+ int err;
+
+ /* BUG_ON(IS_ROOT(dentry)); */
+ page = alloc_page(GFP_KERNEL);
+ if (page == NULL)
+ return mnt;
+
+ fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
+ if (fs_locations == NULL)
+ goto out_free;
+
+ /* Get locations */
+ mnt = ERR_PTR(-ENOENT);
+
+ parent = dget_parent(dentry);
+ dprintk("%s: getting locations for %pd2\n",
+ __func__, dentry);
+
+ err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
+ dput(parent);
+ if (err != 0 ||
+ fs_locations->nlocations <= 0 ||
+ fs_locations->fs_path.ncomponents <= 0)
+ goto out_free;
+
+ mnt = nfs_follow_referral(dentry, fs_locations);
+out_free:
+ __free_page(page);
+ kfree(fs_locations);
+ return mnt;
+}
+
+struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
+ struct nfs_fh *fh, struct nfs_fattr *fattr)
+{
+ rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
+ struct dentry *parent = dget_parent(dentry);
+ struct inode *dir = d_inode(parent);
+ const struct qstr *name = &dentry->d_name;
+ struct rpc_clnt *client;
+ struct vfsmount *mnt;
+
+ /* Look it up again to get its attributes and sec flavor */
+ client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
+ dput(parent);
+ if (IS_ERR(client))
+ return ERR_CAST(client);
+
+ if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
+ mnt = nfs_do_refmount(client, dentry);
+ goto out;
+ }
+
+ if (client->cl_auth->au_flavor != flavor)
+ flavor = client->cl_auth->au_flavor;
+ mnt = nfs_do_submount(dentry, fh, fattr, flavor);
+out:
+ rpc_shutdown_client(client);
+ return mnt;
+}
+
+/*
+ * Try one location from the fs_locations array.
+ *
+ * Returns zero on success, or a negative errno value.
+ */
+static int nfs4_try_replacing_one_location(struct nfs_server *server,
+ char *page, char *page2,
+ const struct nfs4_fs_location *location)
+{
+ const size_t addr_bufsize = sizeof(struct sockaddr_storage);
+ struct net *net = rpc_net_ns(server->client);
+ struct sockaddr *sap;
+ unsigned int s;
+ size_t salen;
+ int error;
+
+ sap = kmalloc(addr_bufsize, GFP_KERNEL);
+ if (sap == NULL)
+ return -ENOMEM;
+
+ error = -ENOENT;
+ for (s = 0; s < location->nservers; s++) {
+ const struct nfs4_string *buf = &location->servers[s];
+ char *hostname;
+
+ if (buf->len <= 0 || buf->len > PAGE_SIZE)
+ continue;
+
+ if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
+ continue;
+
+ salen = nfs_parse_server_name(buf->data, buf->len,
+ sap, addr_bufsize, net);
+ if (salen == 0)
+ continue;
+ rpc_set_port(sap, NFS_PORT);
+
+ error = -ENOMEM;
+ hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
+ if (hostname == NULL)
+ break;
+
+ error = nfs4_update_server(server, hostname, sap, salen, net);
+ kfree(hostname);
+ if (error == 0)
+ break;
+ }
+
+ kfree(sap);
+ return error;
+}
+
+/**
+ * nfs4_replace_transport - set up transport to destination server
+ *
+ * @server: export being migrated
+ * @locations: fs_locations array
+ *
+ * Returns zero on success, or a negative errno value.
+ *
+ * The client tries all the entries in the "locations" array, in the
+ * order returned by the server, until one works or the end of the
+ * array is reached.
+ */
+int nfs4_replace_transport(struct nfs_server *server,
+ const struct nfs4_fs_locations *locations)
+{
+ char *page = NULL, *page2 = NULL;
+ int loc, error;
+
+ error = -ENOENT;
+ if (locations == NULL || locations->nlocations <= 0)
+ goto out;
+
+ error = -ENOMEM;
+ page = (char *) __get_free_page(GFP_USER);
+ if (!page)
+ goto out;
+ page2 = (char *) __get_free_page(GFP_USER);
+ if (!page2)
+ goto out;
+
+ for (loc = 0; loc < locations->nlocations; loc++) {
+ const struct nfs4_fs_location *location =
+ &locations->locations[loc];
+
+ if (location == NULL || location->nservers <= 0 ||
+ location->rootpath.ncomponents == 0)
+ continue;
+
+ error = nfs4_try_replacing_one_location(server, page,
+ page2, location);
+ if (error == 0)
+ break;
+ }
+
+out:
+ free_page((unsigned long)page);
+ free_page((unsigned long)page2);
+ return error;
+}