+/**
+ * @brief Do the smb chaining at a buffer level
+ * @param[in] poutbuf Pointer to the talloc'ed buffer to be modified
+ * @param[in] smb_command The command that we want to issue
+ * @param[in] wct How many words?
+ * @param[in] vwv The words, already in network order
+ * @param[in] bytes_alignment How shall we align "bytes"?
+ * @param[in] num_bytes How many bytes?
+ * @param[in] bytes The data the request ships
+ *
+ * smb_splice_chain() adds the vwv and bytes to the request already present in
+ * *poutbuf.
+ */
+
+bool smb_splice_chain(uint8_t **poutbuf, uint8_t smb_command,
+ uint8_t wct, const uint16_t *vwv,
+ size_t bytes_alignment,
+ uint32_t num_bytes, const uint8_t *bytes)
+{
+ uint8_t *outbuf;
+ size_t old_size, new_size;
+ size_t ofs;
+ size_t chain_padding = 0;
+ size_t bytes_padding = 0;
+ bool first_request;
+
+ old_size = talloc_get_size(*poutbuf);
+
+ /*
+ * old_size == smb_wct means we're pushing the first request in for
+ * libsmb/
+ */
+
+ first_request = (old_size == smb_wct);
+
+ if (!first_request && ((old_size % 4) != 0)) {
+ /*
+ * Align the wct field of subsequent requests to a 4-byte
+ * boundary
+ */
+ chain_padding = 4 - (old_size % 4);
+ }
+
+ /*
+ * After the old request comes the new wct field (1 byte), the vwv's
+ * and the num_bytes field. After at we might need to align the bytes
+ * given to us to "bytes_alignment", increasing the num_bytes value.
+ */
+
+ new_size = old_size + chain_padding + 1 + wct * sizeof(uint16_t) + 2;
+
+ if ((bytes_alignment != 0) && ((new_size % bytes_alignment) != 0)) {
+ bytes_padding = bytes_alignment - (new_size % bytes_alignment);
+ }
+
+ new_size += bytes_padding + num_bytes;
+
+ if ((smb_command != SMBwriteX) && (new_size > 0xffff)) {
+ DEBUG(1, ("splice_chain: %u bytes won't fit\n",
+ (unsigned)new_size));
+ return false;
+ }
+
+ outbuf = TALLOC_REALLOC_ARRAY(NULL, *poutbuf, uint8_t, new_size);
+ if (outbuf == NULL) {
+ DEBUG(0, ("talloc failed\n"));
+ return false;
+ }
+ *poutbuf = outbuf;
+
+ if (first_request) {
+ SCVAL(outbuf, smb_com, smb_command);
+ } else {
+ size_t andx_cmd_ofs;
+
+ if (!find_andx_cmd_ofs(outbuf, &andx_cmd_ofs)) {
+ DEBUG(1, ("invalid command chain\n"));
+ *poutbuf = TALLOC_REALLOC_ARRAY(
+ NULL, *poutbuf, uint8_t, old_size);
+ return false;
+ }
+
+ if (chain_padding != 0) {
+ memset(outbuf + old_size, 0, chain_padding);
+ old_size += chain_padding;
+ }
+
+ SCVAL(outbuf, andx_cmd_ofs, smb_command);
+ SSVAL(outbuf, andx_cmd_ofs + 2, old_size - 4);
+ }
+
+ ofs = old_size;
+
+ /*
+ * Push the chained request:
+ *
+ * wct field
+ */
+
+ SCVAL(outbuf, ofs, wct);
+ ofs += 1;
+
+ /*
+ * vwv array
+ */
+
+ memcpy(outbuf + ofs, vwv, sizeof(uint16_t) * wct);
+ ofs += sizeof(uint16_t) * wct;
+
+ /*
+ * bcc (byte count)
+ */
+
+ SSVAL(outbuf, ofs, num_bytes + bytes_padding);
+ ofs += sizeof(uint16_t);
+
+ /*
+ * padding
+ */
+
+ if (bytes_padding != 0) {
+ memset(outbuf + ofs, 0, bytes_padding);
+ ofs += bytes_padding;
+ }
+
+ /*
+ * The bytes field
+ */
+
+ memcpy(outbuf + ofs, bytes, num_bytes);
+
+ return true;
+}
+
git.samba.org / tprouty / samba.git / blobdiff