[PATCH] cifs: Avoid field over-reading memcpy()

From: Kees Cook
Date: Mon Jun 21 2021 - 17:44:51 EST


In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally reading across neighboring fields.

Instead of using memcpy to read across multiple struct members, just
perform per-member assignments as already done for other members.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/cifs/smb2pdu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 31784e3fa96f..962826dc3316 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2892,7 +2892,10 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
#endif /* CIFS_DEBUG2 */

if (buf) {
- memcpy(buf, &rsp->CreationTime, 32);
+ buf->CreationTime = rsp->CreationTime;
+ buf->LastAccessTime = rsp->LastAccessTime;
+ buf->LastWriteTime = rsp->LastWriteTime;
+ buf->ChangeTime = rsp->ChangeTime;
buf->AllocationSize = rsp->AllocationSize;
buf->EndOfFile = rsp->EndofFile;
buf->Attributes = rsp->FileAttributes;
--
2.30.2