[PATCH 4.14 32/68] CIFS: Fix credit calculation for encrypted reads with errors

From: Greg Kroah-Hartman
Date: Tue Jan 29 2019 - 06:48:53 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>

commit ec678eae746dd25766a61c4095e2b649d3b20b09 upstream.

We do need to account for credits received in error responses
to read requests on encrypted sessions.

Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Reviewed-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/cifs/smb2ops.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2531,11 +2531,23 @@ handle_read_data(struct TCP_Server_Info
server->ops->is_status_pending(buf, server, 0))
return -1;

- rdata->result = server->ops->map_error(buf, false);
+ /* set up first two iov to get credits */
+ rdata->iov[0].iov_base = buf;
+ rdata->iov[0].iov_len = 4;
+ rdata->iov[1].iov_base = buf + 4;
+ rdata->iov[1].iov_len =
+ min_t(unsigned int, buf_len, server->vals->read_rsp_size) - 4;
+ cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
+ rdata->iov[0].iov_base, rdata->iov[0].iov_len);
+ cifs_dbg(FYI, "1: iov_base=%p iov_len=%zu\n",
+ rdata->iov[1].iov_base, rdata->iov[1].iov_len);
+
+ rdata->result = server->ops->map_error(buf, true);
if (rdata->result != 0) {
cifs_dbg(FYI, "%s: server returned error %d\n",
__func__, rdata->result);
- dequeue_mid(mid, rdata->result);
+ /* normal error on read response */
+ dequeue_mid(mid, false);
return 0;
}

@@ -2605,14 +2617,6 @@ handle_read_data(struct TCP_Server_Info
return 0;
}

- /* set up first iov for signature check */
- rdata->iov[0].iov_base = buf;
- rdata->iov[0].iov_len = 4;
- rdata->iov[1].iov_base = buf + 4;
- rdata->iov[1].iov_len = server->vals->read_rsp_size - 4;
- cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
- rdata->iov[0].iov_base, server->vals->read_rsp_size);
-
length = rdata->copy_into_pages(server, rdata, &iter);

kfree(bvec);