nfsd4: don't allow owner override on 4.1 CLAIM_FH opens (9f415eb2) · Commits · 戴 / test

The Linux client is using CLAIM_FH to implement regular opens, not just recovery cases, so it depends on the server to check permissions correctly. Therefore the owner override, which may make sense in the delegation recovery case, isn't right in the CLAIM_FH case. Symptoms: on a client with "NFSv4.1: Enable open-by-filehandle", Bryan noticed this: touch test.txt chmod 000 test.txt echo test > test.txt succeeding. Cc: stable@kernel.org Reported-by:

Bryan Schumaker <bjschuma@netapp.com> Signed-off-by:

J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4proc.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -279,6 +279,7 @@ do_open_fhandle(struct svc_rqst rqstp, struct nfsd4_compound_state cstate, str
		{
		struct svc_fh *current_fh = &cstate->current_fh;
		__be32 status;
		int accmode = 0;

		/* We don't know the target directory, and therefore can not
		* set the change info
		@@ -290,9 +291,19 @@ do_open_fhandle(struct svc_rqst rqstp, struct nfsd4_compound_state cstate, str

		open->op_truncate = (open->op_iattr.ia_valid & ATTR_SIZE) &&
		(open->op_iattr.ia_size == 0);
		/*
		* In the delegation case, the client is telling us about an
		* open that it already performed locally, some time ago. We
		* should let it succeed now if possible.
		*
		* In the case of a CLAIM_FH open, on the other hand, the client
		* may be counting on us to enforce permissions (the Linux 4.1
		* client uses this for normal opens, for example).
		*/
		if (open->op_claim_type == NFS4_OPEN_CLAIM_DELEG_CUR_FH)
		accmode = NFSD_MAY_OWNER_OVERRIDE;

		status = do_open_permission(rqstp, current_fh, open,
		NFSD_MAY_OWNER_OVERRIDE);
		status = do_open_permission(rqstp, current_fh, open, accmode);

		return status;
		}

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