From 48923d2a9d4f6ca909102061a4240b9896ff8ea2 Mon Sep 17 00:00:00 2001 From: Aurelien Aptel Date: Tue, 17 Oct 2017 14:47:17 +0200 Subject: [PATCH] CIFS: do not send invalid input buffer on QUERY_INFO requests query_info() doesn't use the InputBuffer field of the QUERY_INFO request, therefore according to [MS-SMB2] it must: a) set the InputBufferOffset to 0 b) send a zero-length InputBuffer Doing a) is trivial but b) is a bit more tricky. The packet is allocated according to it's StructureSize, which takes into account an extra 1 byte buffer which we don't need here. StructureSize fields must have constant values no matter the actual length of the whole packet so we can't just edit that constant. Both the NetBIOS-over-TCP message length ("rfc1002 length") L and the iovec length L' have to be updated. Since L' is computed from L we just update L by decrementing it by one. Signed-off-by: Aurelien Aptel Signed-off-by: Steve French --- fs/cifs/smb2pdu.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index ba3865b338d8..fa17caa56128 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2191,9 +2191,13 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon, req->PersistentFileId = persistent_fid; req->VolatileFileId = volatile_fid; req->AdditionalInformation = cpu_to_le32(additional_info); - /* 4 for rfc1002 length field and 1 for Buffer */ - req->InputBufferOffset = - cpu_to_le16(sizeof(struct smb2_query_info_req) - 1 - 4); + + /* + * We do not use the input buffer (do not send extra byte) + */ + req->InputBufferOffset = 0; + inc_rfc1001_len(req, -1); + req->OutputBufferLength = cpu_to_le32(output_len); iov[0].iov_base = (char *)req;