From 7ebb931598cd95cccea10d4bc4c0123a464ea565 Mon Sep 17 00:00:00 2001 From: Bryan Schumaker Date: Thu, 24 Mar 2011 17:12:30 +0000 Subject: NFS: use secinfo when crossing mountpoints A submount may use different security than the parent mount does. We should figure out what sec flavor the submount uses at mount time. Signed-off-by: Bryan Schumaker Signed-off-by: Trond Myklebust --- fs/nfs/namespace.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 110 insertions(+), 3 deletions(-) (limited to 'fs/nfs/namespace.c') diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index b02720864ded..ad92bf731ff5 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "internal.h" #define NFSDBG_FACILITY NFSDBG_VFS @@ -27,7 +28,8 @@ int nfs_mountpoint_expiry_timeout = 500 * HZ; static struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh, - struct nfs_fattr *fattr); + struct nfs_fattr *fattr, + rpc_authflavor_t authflavor); /* * nfs_path - reconstruct the path given an arbitrary dentry @@ -116,6 +118,100 @@ Elong: return ERR_PTR(-ENAMETOOLONG); } +#ifdef CONFIG_NFS_V4 +static rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors, struct inode *inode) +{ + struct gss_api_mech *mech; + struct xdr_netobj oid; + int i; + rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX; + + for (i = 0; i < flavors->num_flavors; i++) { + struct nfs4_secinfo_flavor *flavor; + flavor = &flavors->flavors[i]; + + if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) { + pseudoflavor = flavor->flavor; + break; + } else if (flavor->flavor == RPC_AUTH_GSS) { + oid.len = flavor->gss.sec_oid4.len; + oid.data = flavor->gss.sec_oid4.data; + mech = gss_mech_get_by_OID(&oid); + if (!mech) + continue; + pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service); + gss_mech_put(mech); + break; + } + } + + return pseudoflavor; +} + +static rpc_authflavor_t nfs_negotiate_security(const struct dentry *parent, const struct dentry *dentry) +{ + int status = 0; + struct page *page; + struct nfs4_secinfo_flavors *flavors; + int (*secinfo)(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *); + rpc_authflavor_t flavor = RPC_AUTH_UNIX; + + secinfo = NFS_PROTO(parent->d_inode)->secinfo; + if (secinfo != NULL) { + page = alloc_page(GFP_KERNEL); + if (!page) { + status = -ENOMEM; + goto out; + } + flavors = page_address(page); + status = secinfo(parent->d_inode, &dentry->d_name, flavors); + flavor = nfs_find_best_sec(flavors, dentry->d_inode); + put_page(page); + } + + return flavor; + +out: + status = -ENOMEM; + return status; +} + +static rpc_authflavor_t nfs_lookup_with_sec(struct nfs_server *server, struct dentry *parent, + struct dentry *dentry, struct path *path, + struct nfs_fh *fh, struct nfs_fattr *fattr) +{ + rpc_authflavor_t flavor; + struct rpc_clnt *clone; + struct rpc_auth *auth; + int err; + + flavor = nfs_negotiate_security(parent, path->dentry); + if (flavor < 0) + goto out; + clone = rpc_clone_client(server->client); + auth = rpcauth_create(flavor, clone); + if (!auth) { + flavor = -EIO; + goto out; + } + err = server->nfs_client->rpc_ops->lookup(clone, parent->d_inode, + &path->dentry->d_name, + fh, fattr); + if (err < 0) + flavor = err; +out: + return flavor; +} +#else /* CONFIG_NFS_V4 */ +static inline rpc_authflavor_t nfs_lookup_with_sec(struct nfs_server *server, + struct dentry *parent, struct dentry *dentry, + struct path *path, struct nfs_fh *fh, + struct nfs_fattr *fattr) +{ + return -EPERM; +} +#endif /* CONFIG_NFS_V4 */ + /* * nfs_d_automount - Handle crossing a mountpoint on the server * @path - The mountpoint @@ -136,6 +232,7 @@ struct vfsmount *nfs_d_automount(struct path *path) struct nfs_fh *fh = NULL; struct nfs_fattr *fattr = NULL; int err; + rpc_authflavor_t flavor = 1; dprintk("--> nfs_d_automount()\n"); @@ -156,6 +253,13 @@ struct vfsmount *nfs_d_automount(struct path *path) err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode, &path->dentry->d_name, fh, fattr); + if (err == -EPERM) { + flavor = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr); + if (flavor < 0) + err = flavor; + else + err = 0; + } dput(parent); if (err != 0) { mnt = ERR_PTR(err); @@ -165,7 +269,7 @@ struct vfsmount *nfs_d_automount(struct path *path) if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) mnt = nfs_do_refmount(path->dentry); else - mnt = nfs_do_submount(path->dentry, fh, fattr); + mnt = nfs_do_submount(path->dentry, fh, fattr, flavor); if (IS_ERR(mnt)) goto out; @@ -232,17 +336,20 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, * @dentry - parent directory * @fh - filehandle for new root dentry * @fattr - attributes for new root inode + * @authflavor - security flavor to use when performing the mount * */ static struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh, - struct nfs_fattr *fattr) + struct nfs_fattr *fattr, + rpc_authflavor_t authflavor) { struct nfs_clone_mount mountdata = { .sb = dentry->d_sb, .dentry = dentry, .fh = fh, .fattr = fattr, + .authflavor = authflavor, }; struct vfsmount *mnt = ERR_PTR(-ENOMEM); char *page = (char *) __get_free_page(GFP_USER); -- cgit v1.2.3