[PATCH 3/3] NFSv4.2: Fix a memory stomp in decode_attr_security_label
From: trondmy@kernel.org
Date: 2022-10-18 22:43:55
Subsystem:
filesystems (vfs and infrastructure), nfs, sunrpc, and lockd clients, the rest · Maintainers:
Alexander Viro, Christian Brauner, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: Trond Myklebust <redacted>
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 <redacted>
---
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 9103e022376a..deec76cf5afe 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c@@ -4236,12 +4236,10 @@ static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap, return -EIO; bitmap[2] &= ~FATTR4_WORD2_SECURITY_LABEL; 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;
--
2.37.3