From: Jeff Layton <jlayton@redhat.com>
Date: Fri, 30 Oct 2009 13:16:22 -0400
Subject: [nfsd] don't allow setting ctime over v4
Message-id: <1256908582-2474-1-git-send-email-jlayton@redhat.com>
Patchwork-id: 21263
O-Subject: [RHEL5.5 PATCH] BZ#497909: nfsd: don't allow setting ctime over v4
Bugzilla: 497909
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Peter Staubach <staubach@redhat.com>

From: J. Bruce Fields <bfields@citi.umich.edu>

(Upstream commit e36cd4a2873c398ba188f16e4087cce7f00a1506)

The NFSv4 server in RHEL5 allows a client to set the ctime over NFSv4.
This shouldn't be allowed according to the RFC. Tested with the
customer-provided reproducer.

Original patch description follows:

	Presumably this is left over from earlier drafts of v4, which listed
	TIME_METADATA as writeable.  It's read-only in rfc 3530, and shouldn't
	be modifiable anyway.

	Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 13123a7..597245c 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -363,20 +363,6 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval, struct iattr *ia
 			goto xdr_error;
 		}
 	}
-	if (bmval[1] & FATTR4_WORD1_TIME_METADATA) {
-		/* We require the high 32 bits of 'seconds' to be 0, and we ignore
-		   all 32 bits of 'nseconds'. */
-		READ_BUF(12);
-		len += 12;
-		READ32(dummy32);
-		if (dummy32)
-			return nfserr_inval;
-		READ32(iattr->ia_ctime.tv_sec);
-		READ32(iattr->ia_ctime.tv_nsec);
-		if (iattr->ia_ctime.tv_nsec >= (u32)1000000000)
-			return nfserr_inval;
-		iattr->ia_valid |= ATTR_CTIME;
-	}
 	if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
 		READ_BUF(4);
 		len += 4;
diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
index c04fb25..ff1b586 100644
--- a/include/linux/nfsd/nfsd.h
+++ b/include/linux/nfsd/nfsd.h
@@ -333,7 +333,7 @@ static inline int is_fsid(struct svc_fh *fh, struct knfsd_fh *reffh)
 (FATTR4_WORD0_SIZE              | FATTR4_WORD0_ACL                                         )
 #define NFSD_WRITEABLE_ATTRS_WORD1                                                          \
 (FATTR4_WORD1_MODE              | FATTR4_WORD1_OWNER         | FATTR4_WORD1_OWNER_GROUP     \
- | FATTR4_WORD1_TIME_ACCESS_SET | FATTR4_WORD1_TIME_METADATA | FATTR4_WORD1_TIME_MODIFY_SET)
+ | FATTR4_WORD1_TIME_ACCESS_SET | FATTR4_WORD1_TIME_MODIFY_SET)
 
 #endif /* CONFIG_NFSD_V4 */