Commit 576a47e9 authored Jul 26, 2019 by Jia-Ju Bai Committed by Greg Kroah-Hartman Oct 11, 2019

fs: nfs: Fix possible null-pointer dereferences in encode_attrs()



[ Upstream commit e2751463eaa6f9fec8fea80abbdc62dbc487b3c5 ]

In encode_attrs(), there is an if statement on line 1145 to check
whether label is NULL:
    if (label && (attrmask[2] & FATTR4_WORD2_SECURITY_LABEL))

When label is NULL, it is used on lines 1178-1181:
    *p++ = cpu_to_be32(label->lfs);
    *p++ = cpu_to_be32(label->pi);
    *p++ = cpu_to_be32(label->len);
    p = xdr_encode_opaque_fixed(p, label->label, label->len);

To fix these bugs, label is checked before being used.

These bugs are found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 27551dbe

fs/nfs/nfs4xdr.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1132,7 +1132,7 @@ static void encode_attrs(struct xdr_stream xdr, const struct iattr iap,
		} else
		*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
		}
		if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
		if (label && (bmval[2] & FATTR4_WORD2_SECURITY_LABEL)) {
		*p++ = cpu_to_be32(label->lfs);
		*p++ = cpu_to_be32(label->pi);
		*p++ = cpu_to_be32(label->len);