Commit ea465551 authored May 05, 2017 by Ari Kauppi Committed by Greg Kroah-Hartman May 25, 2017

nfsd: fix undefined behavior in nfsd4_layout_verify



commit b550a32e60a4941994b437a8d662432a486235a5 upstream.

  UBSAN: Undefined behaviour in fs/nfsd/nfs4proc.c:1262:34
  shift exponent 128 is too large for 32-bit type 'int'

Depending on compiler+architecture, this may cause the check for
layout_type to succeed for overly large values (which seems to be the
case with amd64). The large value will be later used in de-referencing
nfsd4_layout_ops for function pointers.

Reported-by: Jani Tuovila <tuovila@synopsys.com>
Signed-off-by: Ari Kauppi <ari@synopsys.com>
[colin.king@canonical.com: use LAYOUT_TYPE_MAX instead of 32]
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent f2b6f508

fs/nfsd/nfs4proc.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1273,7 +1273,8 @@ nfsd4_layout_verify(struct svc_export *exp, unsigned int layout_type)
		return NULL;
		}

		if (!(exp->ex_layout_types & (1 << layout_type))) {
		if (layout_type >= LAYOUT_TYPE_MAX \|\|
		!(exp->ex_layout_types & (1 << layout_type))) {
		dprintk("%s: layout type %d not supported\n",
		__func__, layout_type);
		return NULL;