| From b4487b93545214a9db8cbf32e86411677b0cca21 Mon Sep 17 00:00:00 2001 |
| From: Jeffrey Mitchell <jeffrey.mitchell@starlab.io> |
| Date: Wed, 5 Aug 2020 12:23:19 -0500 |
| Subject: [PATCH] nfs: Fix getxattr kernel panic and memory overflow |
| |
| commit b4487b93545214a9db8cbf32e86411677b0cca21 upstream. |
| |
| Move the buffer size check to decode_attr_security_label() before memcpy() |
| Only call memcpy() if the buffer is large enough |
| |
| Fixes: aa9c2669626c ("NFS: Client implementation of Labeled-NFS") |
| Signed-off-by: Jeffrey Mitchell <jeffrey.mitchell@starlab.io> |
| [Trond: clean up duplicate test of label->len != 0] |
| Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> |
| |
| diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c |
| index 113e0d6dd3d3..5db240688d4e 100644 |
| --- a/fs/nfs/nfs4proc.c |
| +++ b/fs/nfs/nfs4proc.c |
| @@ -5856,8 +5856,6 @@ static int _nfs4_get_security_label(struct inode *inode, void *buf, |
| return ret; |
| if (!(fattr.valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL)) |
| return -ENOENT; |
| - if (buflen < label.len) |
| - return -ERANGE; |
| return 0; |
| } |
| |
| diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c |
| index 388ac520b104..79018938d6b3 100644 |
| --- a/fs/nfs/nfs4xdr.c |
| +++ b/fs/nfs/nfs4xdr.c |
| @@ -4166,7 +4166,11 @@ static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap, |
| return -EIO; |
| if (len < NFS4_MAXLABELLEN) { |
| if (label) { |
| - memcpy(label->label, p, len); |
| + if (label->len) { |
| + if (label->len < len) |
| + return -ERANGE; |
| + memcpy(label->label, p, len); |
| + } |
| label->len = len; |
| label->pi = pi; |
| label->lfs = lfs; |
| -- |
| 2.27.0 |
| |
