cifs: fix memory leak in smb2_copychunk_range

When using smb2_copychunk_range() for large ranges we will
run through several iterations of a loop calling SMB2_ioctl()
but never actually free the returned buffer except for the final
iteration.
This leads to memory leaks everytime a large copychunk is requested.

Fixes: 9bf0c9cd4314 ("CIFS: Fix SMB2/SMB3 Copy offload support (refcopy) for large files")
Cc: <stable@vger.kernel.org>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index dd0eb66..c693624 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1861,6 +1861,8 @@ smb2_copychunk_range(const unsigned int xid,
                        cpu_to_le32(min_t(u32, len, tcon->max_bytes_chunk));
 
                /* Request server copy to target from src identified by key */
+               kfree(retbuf);
+               retbuf = NULL;
                rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid, FSCTL_SRV_COPYCHUNK_WRITE,
                        true /* is_fsctl */, (char *)pcchunk,