diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index c0d102615d0a..f9b74daf962a 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -416,18 +416,22 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses) security_blob = smb2_get_data_area_len(&blob_offset, &blob_length, &rsp->hdr); - if (blob_length == 0) { - cifs_dbg(VFS, "missing security blob on negprot\n"); - rc = -EIO; - goto neg_exit; - } + /* + * See MS-SMB2 section 2.2.4: if no blob, client picks default which + * for us will be + * ses->sectype = RawNTLMSSP; + * but for time being this is our only auth choice so doesn't matter. + * We just found a server which sets blob length to zero expecting raw. + */ + if (blob_length == 0) + cifs_dbg(FYI, "missing security blob on negprot\n"); rc = cifs_enable_signing(server, ses->sign); #ifdef CONFIG_SMB2_ASN1 /* BB REMOVEME when updated asn1.c ready */ if (rc) goto neg_exit; - - rc = decode_neg_token_init(security_blob, blob_length, + if (blob_length) + rc = decode_neg_token_init(security_blob, blob_length, &server->sec_type); if (rc == 1) rc = 0;