diff -up linux-2.6.32.i686/fs/nfsd/export.c.save linux-2.6.32.i686/fs/nfsd/export.c
--- linux-2.6.32.i686/fs/nfsd/export.c.save 2009-12-04 10:24:17.000000000 -0500
+++ linux-2.6.32.i686/fs/nfsd/export.c 2009-12-04 10:40:52.000000000 -0500
@@ -372,10 +372,12 @@ static struct svc_export *svc_export_loo
static int check_export(struct inode *inode, int flags, unsigned char *uuid)
{
- /* We currently export only dirs and regular files.
- * This is what umountd does.
+ /*
+ * We currently export only dirs, regular files, and (for v4
+ * pseudoroot) symlinks.
*/
if (!S_ISDIR(inode->i_mode) &&
+ !S_ISLNK(inode->i_mode) &&
!S_ISREG(inode->i_mode))
return -ENOTDIR;
@@ -1425,6 +1427,7 @@ static struct flags {
{ NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
{ NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
{ NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
+ { NFSEXP_V4ROOT, {"v4root", ""}},
#ifdef MSNFS
{ NFSEXP_MSNFS, {"msnfs", ""}},
#endif
@@ -1505,7 +1508,7 @@ static int e_show(struct seq_file *m, vo
struct svc_export *exp = container_of(cp, struct svc_export, h);
if (p == SEQ_START_TOKEN) {
- seq_puts(m, "# Version 1.1\n");
+ seq_puts(m, "# Version 1.2\n");
seq_puts(m, "# Path Client(Flags) # IPs\n");
return 0;
}
diff -up linux-2.6.32.i686/fs/nfsd/nfs4xdr.c.save linux-2.6.32.i686/fs/nfsd/nfs4xdr.c
--- linux-2.6.32.i686/fs/nfsd/nfs4xdr.c.save 2009-12-04 10:24:17.000000000 -0500
+++ linux-2.6.32.i686/fs/nfsd/nfs4xdr.c 2009-12-04 10:26:49.000000000 -0500
@@ -2204,11 +2204,14 @@ nfsd4_encode_dirent_fattr(struct nfsd4_r
* we will not follow the cross mount and will fill the attribtutes
* directly from the mountpoint dentry.
*/
- if (d_mountpoint(dentry) && !attributes_need_mount(cd->rd_bmval))
- ignore_crossmnt = 1;
- else if (d_mountpoint(dentry)) {
+ if (nfsd_mountpoint(dentry, exp)) {
int err;
+ if (!(exp->ex_flags & NFSEXP_V4ROOT)
+ && !attributes_need_mount(cd->rd_bmval)) {
+ ignore_crossmnt = 1;
+ goto out_encode;
+ }
/*
* Why the heck aren't we just using nfsd_lookup??
* Different "."/".." handling? Something else?
@@ -2224,6 +2227,7 @@ nfsd4_encode_dirent_fattr(struct nfsd4_r
goto out_put;
}
+out_encode:
nfserr = nfsd4_encode_fattr(NULL, exp, dentry, p, buflen, cd->rd_bmval,
cd->rd_rqstp, ignore_crossmnt);
out_put:
diff -up linux-2.6.32.i686/fs/nfsd/nfsfh.c.save linux-2.6.32.i686/fs/nfsd/nfsfh.c
--- linux-2.6.32.i686/fs/nfsd/nfsfh.c.save 2009-12-04 10:24:17.000000000 -0500
+++ linux-2.6.32.i686/fs/nfsd/nfsfh.c 2009-12-04 10:38:26.000000000 -0500
@@ -109,6 +109,36 @@ static __be32 nfsd_setuser_and_check_por
return nfserrno(nfsd_setuser(rqstp, exp));
}
+static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
+ struct dentry *dentry, struct svc_export *exp)
+{
+ if (!(exp->ex_flags & NFSEXP_V4ROOT))
+ return nfs_ok;
+ /*
+ * v2/v3 clients have no need for the V4ROOT export--they use
+ * the mount protocl instead; also, further V4ROOT checks may be
+ * in v4-specific code, in which case v2/v3 clients could bypass
+ * them.
+ */
+ if (!nfsd_v4client(rqstp))
+ return nfserr_stale;
+ /*
+ * We're exposing only the directories and symlinks that have to be
+ * traversed on the way to real exports:
+ */
+ if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
+ !S_ISLNK(dentry->d_inode->i_mode)))
+ return nfserr_stale;
+ /*
+ * A pseudoroot export gives permission to access only one
+ * single directory; the kernel has to make another upcall
+ * before granting access to anything else under it:
+ */
+ if (unlikely(dentry != exp->ex_path.dentry))
+ return nfserr_stale;
+ return nfs_ok;
+}
+
/*
* Use the given filehandle to look up the corresponding export and
* dentry. On success, the results are used to set fh_export and
@@ -317,6 +347,13 @@ fh_verify(struct svc_rqst *rqstp, struct
goto out;
}
+ /*
+ * Do some spoof checking if we are on the pseudo root
+ */
+ error = check_pseudo_root(rqstp, dentry, exp);
+ if (error)
+ goto out;
+
error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
if (error)
goto out;
diff -up linux-2.6.32.i686/fs/nfsd/vfs.c.save linux-2.6.32.i686/fs/nfsd/vfs.c
--- linux-2.6.32.i686/fs/nfsd/vfs.c.save 2009-12-04 10:24:18.000000000 -0500
+++ linux-2.6.32.i686/fs/nfsd/vfs.c 2009-12-04 10:35:04.000000000 -0500
@@ -89,12 +89,6 @@ struct raparm_hbucket {
#define RAPARM_HASH_MASK (RAPARM_HASH_SIZE-1)
static struct raparm_hbucket raparm_hash[RAPARM_HASH_SIZE];
-static inline int
-nfsd_v4client(struct svc_rqst *rq)
-{
- return rq->rq_prog == NFS_PROGRAM && rq->rq_vers == 4;
-}
-
/*
* Called from nfsd_lookup and encode_dirent. Check if we have crossed
* a mount point.
@@ -116,8 +110,16 @@ nfsd_cross_mnt(struct svc_rqst *rqstp, s
exp2 = rqst_exp_get_by_name(rqstp, &path);
if (IS_ERR(exp2)) {
- if (PTR_ERR(exp2) != -ENOENT)
- err = PTR_ERR(exp2);
+ err = PTR_ERR(exp2);
+ /*
+ * We normally allow NFS clients to continue
+ * "underneath" a mountpoint that is not exported.
+ * The exception is V4ROOT, where no traversal is ever
+ * allowed without an explicit export of the new
+ * directory.
+ */
+ if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
+ err = 0;
path_put(&path);
goto out;
}
@@ -141,6 +143,19 @@ out:
return err;
}
+/*
+ * For nfsd purposes, we treat V4ROOT exports as though there was an
+ * export at *every* directory.
+ */
+int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
+{
+ if (d_mountpoint(dentry))
+ return 1;
+ if (!(exp->ex_flags & NFSEXP_V4ROOT))
+ return 0;
+ return dentry->d_inode != NULL;
+}
+
__be32
nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
const char *name, unsigned int len,
@@ -208,7 +223,7 @@ nfsd_lookup_dentry(struct svc_rqst *rqst
/*
* check if we have crossed a mount point ...
*/
- if (d_mountpoint(dentry)) {
+ if (nfsd_mountpoint(dentry, exp)) {
if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
dput(dentry);
goto out_nfserr;
diff -up linux-2.6.32.i686/include/linux/nfsd/export.h.save linux-2.6.32.i686/include/linux/nfsd/export.h
--- linux-2.6.32.i686/include/linux/nfsd/export.h.save 2009-12-04 10:24:18.000000000 -0500
+++ linux-2.6.32.i686/include/linux/nfsd/export.h 2009-12-04 10:25:08.000000000 -0500
@@ -39,7 +39,17 @@
#define NFSEXP_FSID 0x2000
#define NFSEXP_CROSSMOUNT 0x4000
#define NFSEXP_NOACL 0x8000 /* reserved for possible ACL related use */
-#define NFSEXP_ALLFLAGS 0xFE3F
+/*
+ * The NFSEXP_V4ROOT flag causes the kernel to give access only to NFSv4
+ * clients, and only to the single directory that is the root of the
+ * export; further lookup and readdir operations are treated as if every
+ * subdirectory was a mountpoint, and ignored if they are not themselves
+ * exported. This is used by nfsd and mountd to construct the NFSv4
+ * pseudofilesystem, which provides access only to paths leading to each
+ * exported filesystem.
+ */
+#define NFSEXP_V4ROOT 0x10000
+#define NFSEXP_ALLFLAGS 0x1FE3F
/* The flags that may vary depending on security flavor: */
#define NFSEXP_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \
diff -up linux-2.6.32.i686/include/linux/nfsd/nfsd.h.save linux-2.6.32.i686/include/linux/nfsd/nfsd.h
--- linux-2.6.32.i686/include/linux/nfsd/nfsd.h.save 2009-12-04 10:24:18.000000000 -0500
+++ linux-2.6.32.i686/include/linux/nfsd/nfsd.h 2009-12-04 10:39:18.000000000 -0500
@@ -86,6 +86,7 @@ __be32 nfsd_lookup_dentry(struct svc_r
struct svc_export **, struct dentry **);
__be32 nfsd_setattr(struct svc_rqst *, struct svc_fh *,
struct iattr *, int, time_t);
+int nfsd_mountpoint(struct dentry *, struct svc_export *);
#ifdef CONFIG_NFSD_V4
__be32 nfsd4_set_nfs4_acl(struct svc_rqst *, struct svc_fh *,
struct nfs4_acl *);
@@ -394,6 +395,10 @@ static inline u32 nfsd_suppattrs2(u32 mi
return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD2
: NFSD4_SUPPORTED_ATTRS_WORD2;
}
+static inline int nfsd_v4client(struct svc_rqst *rq)
+{
+ return rq->rq_prog == NFS_PROGRAM && rq->rq_vers == 4;
+}
/* These will return ERR_INVAL if specified in GETATTR or READDIR. */
#define NFSD_WRITEONLY_ATTRS_WORD1 \