From: Trond Myklebust trond.myklebust@hammerspace.com
[ Upstream commit 43c1031f7110967c240cb6e922adcfc4b8899183 ]
We must not change the value of label->len if it is zero, since that indicates we stored a label.
Fixes: b4487b935452 ("nfs: Fix getxattr kernel panic and memory overflow") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/nfs4xdr.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index b50c97c6aecb..fc5583531fc0 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -4160,12 +4160,10 @@ static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap, if (unlikely(!p)) goto out_overflow; if (len < NFS4_MAXLABELLEN) { - if (label) { - if (label->len) { - if (label->len < len) - return -ERANGE; - memcpy(label->label, p, len); - } + if (label && label->len) { + if (label->len < len) + return -ERANGE; + memcpy(label->label, p, len); label->len = len; label->pi = pi; label->lfs = lfs;