lib/smb2-cmd-read.c

   1 /* -*-  mode:c; tab-width:8; c-basic-offset:8; indent-tabs-mode:nil;  -*- */
   2 /*
   3    Copyright (C) 2016 by Ronnie Sahlberg <ronniesahlberg@gmail.com>
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as published by
   7    the Free Software Foundation; either version 2.1 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program; if not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #ifdef HAVE_CONFIG_H
  19 #include "config.h"
  20 #endif
  21
  22 #ifndef _GNU_SOURCE
  23 #define _GNU_SOURCE
  24 #endif
  25
  26 #ifdef HAVE_STDINT_H
  27 #include <stdint.h>
  28 #endif
  29
  30 #ifdef HAVE_STDLIB_H
  31 #include <stdlib.h>
  32 #endif
  33
  34 #ifdef HAVE_STRING_H
  35 #include <string.h>
  36 #endif
  37
  38 #ifdef STDC_HEADERS
  39 #include <stddef.h>
  40 #endif
  41
  42 #include <errno.h>
  43
  44 #include "smb2.h"
  45 #include "libsmb2.h"
  46 #include "libsmb2-private.h"
  47
  48 static int
  49 smb2_encode_read_request(struct smb2_context *smb2,
  50                          struct smb2_pdu *pdu,
  51                          struct smb2_read_request *req)
  52 {
  53         int len;
  54         uint8_t *buf;
  55         struct smb2_iovec *iov;
  56
  57         len = SMB2_READ_REQUEST_SIZE & 0xfffffffe;
  58         buf = calloc(len, sizeof(uint8_t));
  59         if (buf == NULL) {
  60                 smb2_set_error(smb2, "Failed to allocate read buffer");
  61                 return -1;
  62         }
  63
  64         iov = smb2_add_iovector(smb2, &pdu->out, buf, len, free);
  65
  66         if (!smb2->supports_multi_credit && req->length > 64 * 1024) {
  67                 req->length = 64 * 1024;
  68                 req->minimum_count = 0;
  69         }
  70         smb2_set_uint16(iov, 0, SMB2_READ_REQUEST_SIZE);
  71         smb2_set_uint8(iov, 3, req->flags);
  72         smb2_set_uint32(iov, 4, req->length);
  73         smb2_set_uint64(iov, 8, req->offset);
  74         memcpy(iov->buf + 16, req->file_id, SMB2_FD_SIZE);
  75         smb2_set_uint32(iov, 32, req->minimum_count);
  76         smb2_set_uint32(iov, 36, req->channel);
  77         smb2_set_uint32(iov, 40, req->remaining_bytes);
  78         smb2_set_uint16(iov, 46, req->read_channel_info_length);
  79
  80         if (req->read_channel_info_length > 0 ||
  81             req->read_channel_info != NULL) {
  82                 smb2_set_error(smb2, "ChannelInfo not yet implemented");
  83                 return -1;
  84         }
  85
  86         /* The buffer must contain at least one byte, even if we do not
  87          * have any read channel info.
  88          */
  89         if (req->read_channel_info == NULL) {
  90                 static uint8_t zero;
  91
  92                 smb2_add_iovector(smb2, &pdu->out, &zero, 1, NULL);
  93         }
  94
  95         return 0;
  96 }
  97
  98 struct smb2_pdu *
  99 smb2_cmd_read_async(struct smb2_context *smb2,
 100                     struct smb2_read_request *req,
 101                     smb2_command_cb cb, void *cb_data)
 102 {
 103         struct smb2_pdu *pdu;
 104
 105         pdu = smb2_allocate_pdu(smb2, SMB2_READ, cb, cb_data);
 106         if (pdu == NULL) {
 107                 return NULL;
 108         }
 109
 110         if (smb2_encode_read_request(smb2, pdu, req)) {
 111                 smb2_free_pdu(smb2, pdu);
 112                 return NULL;
 113         }
 114
 115         /* Add a vector for the buffer that the application gave us */
 116         smb2_add_iovector(smb2, &pdu->in, req->buf,
 117                           req->length, NULL);
 118
 119         if (smb2_pad_to_64bit(smb2, &pdu->out) != 0) {
 120                 smb2_free_pdu(smb2, pdu);
 121                 return NULL;
 122         }
 123
 124         /* Adjust credit charge for large payloads */
 125         if (smb2->supports_multi_credit) {
 126                 pdu->header.credit_charge = (req->length - 1) / 65536 + 1; // 3.1.5.2 of [MS-SMB2]
 127         }
 128
 129         return pdu;
 130 }
 131
 132 int
 133 smb2_process_read_fixed(struct smb2_context *smb2,
 134                         struct smb2_pdu *pdu)
 135 {
 136         struct smb2_read_reply *rep;
 137         struct smb2_iovec *iov = &smb2->in.iov[smb2->in.niov - 1];
 138         uint16_t struct_size;
 139
 140         rep = malloc(sizeof(*rep));
 141         if (rep == NULL) {
 142                 smb2_set_error(smb2, "Failed to allocate read reply");
 143                 return -1;
 144         }
 145         pdu->payload = rep;
 146
 147         smb2_get_uint16(iov, 0, &struct_size);
 148         if (struct_size > SMB2_READ_REPLY_SIZE) {
 149                 smb2_set_error(smb2, "Unexpected size of Read "
 150                                "reply. Expected %d, got %d",
 151                                SMB2_READ_REPLY_SIZE,
 152                                (int)iov->len);
 153                 return -1;
 154         }
 155
 156         smb2_get_uint8(iov, 2, &rep->data_offset);
 157         smb2_get_uint32(iov, 4, &rep->data_length);
 158         smb2_get_uint32(iov, 8, &rep->data_remaining);
 159
 160         if (rep->data_length == 0) {
 161                 return 0;
 162         }
 163
 164         if (rep->data_offset != SMB2_HEADER_SIZE + 16) {
 165                 smb2_set_error(smb2, "Unexpected data offset in Read reply. "
 166                                "Expected %d, got %d",
 167                                16, rep->data_offset);
 168                 return -1;
 169         }
 170
 171         return rep->data_length;
 172 }