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Diffstat (limited to 'fs/nfsd/nfsfh.c')
-rw-r--r--fs/nfsd/nfsfh.c102
1 files changed, 60 insertions, 42 deletions
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 01965b2f3a76..1c12177b908c 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -1,6 +1,4 @@
/*
- * linux/fs/nfsd/nfsfh.c
- *
* NFS server file handle treatment.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
@@ -9,19 +7,11 @@
* ... and again Southern-Winter 2001 to support export_operations
*/
-#include <linux/slab.h>
-#include <linux/fs.h>
-#include <linux/unistd.h>
-#include <linux/string.h>
-#include <linux/stat.h>
-#include <linux/dcache.h>
#include <linux/exportfs.h>
-#include <linux/mount.h>
-#include <linux/sunrpc/clnt.h>
-#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcauth_gss.h>
-#include <linux/nfsd/nfsd.h>
+#include "nfsd.h"
+#include "vfs.h"
#include "auth.h"
#define NFSDDBG_FACILITY NFSDDBG_FH
@@ -96,8 +86,10 @@ nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
struct svc_export *exp)
{
+ int flags = nfsexp_flags(rqstp, exp);
+
/* Check if the request originated from a secure port. */
- if (!rqstp->rq_secure && EX_SECURE(exp)) {
+ if (!rqstp->rq_secure && (flags & NFSEXP_INSECURE_PORT)) {
RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
dprintk(KERN_WARNING
"nfsd: request from insecure port %s!\n",
@@ -109,6 +101,36 @@ static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
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
@@ -232,14 +254,6 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
goto out;
}
- if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
- error = nfsd_setuser_and_check_port(rqstp, exp);
- if (error) {
- dput(dentry);
- goto out;
- }
- }
-
if (S_ISDIR(dentry->d_inode->i_mode) &&
(dentry->d_flags & DCACHE_DISCONNECTED)) {
printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
@@ -294,28 +308,32 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
error = nfsd_set_fh_dentry(rqstp, fhp);
if (error)
goto out;
- dentry = fhp->fh_dentry;
- exp = fhp->fh_export;
- } else {
- /*
- * just rechecking permissions
- * (e.g. nfsproc_create calls fh_verify, then nfsd_create
- * does as well)
- */
- dprintk("nfsd: fh_verify - just checking\n");
- dentry = fhp->fh_dentry;
- exp = fhp->fh_export;
- /*
- * Set user creds for this exportpoint; necessary even
- * in the "just checking" case because this may be a
- * filehandle that was created by fh_compose, and that
- * is about to be used in another nfsv4 compound
- * operation.
- */
- error = nfsd_setuser_and_check_port(rqstp, exp);
- if (error)
- goto out;
}
+ dentry = fhp->fh_dentry;
+ exp = fhp->fh_export;
+ /*
+ * We still have to do all these permission checks, even when
+ * fh_dentry is already set:
+ * - fh_verify may be called multiple times with different
+ * "access" arguments (e.g. nfsd_proc_create calls
+ * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
+ * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
+ * - in the NFSv4 case, the filehandle may have been filled
+ * in by fh_compose, and given a dentry, but further
+ * compound operations performed with that filehandle
+ * still need permissions checks. In the worst case, a
+ * mountpoint crossing may have changed the export
+ * options, and we may now need to use a different uid
+ * (for example, if different id-squashing options are in
+ * effect on the new filesystem).
+ */
+ error = check_pseudo_root(rqstp, dentry, exp);
+ if (error)
+ goto out;
+
+ error = nfsd_setuser_and_check_port(rqstp, exp);
+ if (error)
+ goto out;
error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
if (error)
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