From: Steve French <smfrench@xxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 7ff8d45c9dccf0744404d6fe44468ede7c1b9533 upstream.
We were off by one calculating the length of ioctls in some cases
because the protocol specification for SMB2 ioctl includes a mininum
one byte payload but not all SMB2 ioctl requests actually have
a data buffer to send. We were also not zeroing out the
return buffer (in case of error this is helpful).
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
fs/cifs/smb2pdu.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1f096f694030..1bf0ba805ef5 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1228,6 +1228,7 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
cifs_dbg(FYI, "SMB2 IOCTL\n");
+ *out_data = NULL;
/* zero out returned data len, in case of error */
if (plen)
*plen = 0;
@@ -1273,11 +1274,23 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
req->Flags = 0;
iov[0].iov_base = (char *)req;
- /* 4 for rfc1002 length field */
- iov[0].iov_len = get_rfc1002_length(req) + 4;
- if (indatalen)
- inc_rfc1001_len(req, indatalen);
+ /*
+ * If no input data, the size of ioctl struct in
+ * protocol spec still includes a 1 byte data buffer,
+ * but if input data passed to ioctl, we do not
+ * want to double count this, so we do not send
+ * the dummy one byte of data in iovec[0] if sending
+ * input data (in iovec[1]). We also must add 4 bytes
+ * in first iovec to allow for rfc1002 length field.
+ */
+
+ if (indatalen) {
+ iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;
+ inc_rfc1001_len(req, indatalen - 1);
+ } else
+ iov[0].iov_len = get_rfc1002_length(req) + 4;
+
rc = SendReceive2(xid, ses, iov, num_iovecs, &resp_buftype, 0);
rsp = (struct smb2_ioctl_rsp *)iov[0].iov_base;
--
2.4.2
--
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