svn commit: r226580 - stable/7/libexec/tftpd

[Sean Bruno]

Author: sbruno
Date: Thu Oct 20 19:23:21 2011
New Revision: 226580
URL: http://svn.freebsd.org/changeset/base/226580

Log:
  MFC r224536:
  Confirmed behavior of a Cisco 6509 in production.
  
  In the old TFTP server, there was an undocumented behavior where
  the block counter would rollover to 0 if a file larger
  than 65535 blocks was transferred.  With the default block size
  of 512 octets per block, this is a file size of approximately 32 megabytes.
  
  The new TFTP server code would report an error and stop transferring
  the file if a file was larger than 65535 blocks.
  
  This patch restores the old TFTP server's behavior to the new
  TFTP server code.  If a TFTP client transfers a file larger
  than 65535 blocks, and does *not* specify the "rollover" option,
  then automatically rollover the block counter to 0 every time
  we reach 65535 blocks.
  
  This restores interoperability with the FreeBSD 6 TFTP client.
  Without this change, if a FreeBSD 6 TFTP client tried to
  retrieve a file larger than 65535 blocks from a FreeBSD 9 TFTP server
  , the transfer would fail.
  The same file could be retrieved successfully if the same FreeBSD 6
  TFTP client was used against a FreeBSD 6 TFTP server.
  
  Approved by:  re (kib)
  Tested by: Pawan Gupta <pawang at juniper dot net>,
  Obtained from:  Juniper Networks
  FreeBSD7 Reviewed by: Yahoo Inc.
  
  > Submitted by:  If someone else sent in the change.
  > Reviewed by:   If someone else reviewed your modification.
  > Approved by:   If you needed approval for this commit.
  > Obtained from: If the change is from a third party.
  > MFC after:     N [day[s]|week[s]|month[s]].  Request a reminder email.
  > Security:      Vulnerability reference (one per line) or description.
  > Empty fields above will be automatically removed.
  
  M    tftpd/tftp-transfer.c

Modified:
  stable/7/libexec/tftpd/tftp-transfer.c

Modified: stable/7/libexec/tftpd/tftp-transfer.c
==============================================================================
--- stable/7/libexec/tftpd/tftp-transfer.c	Thu Oct 20 19:16:52 2011	(r226579)
+++ stable/7/libexec/tftpd/tftp-transfer.c	Thu Oct 20 19:23:21 2011	(r226580)
@@ -129,14 +129,16 @@ tftp_send(int peer, uint16_t *block, str
 		(*block)++;
 		if (oldblock > *block) {
 			if (options[OPT_ROLLOVER].o_request == NULL) {
-				tftp_log(LOG_ERR,
-				    "Block rollover but not allowed.");
-				send_error(peer, EBADOP);
-				gettimeofday(&(ts->tstop), NULL);
-				return;
+				/*
+				 * "rollover" option not specified in
+				 * tftp client.  Default to rolling block
+				 * counter to 0.
+				 */
+				*block = 0;
+			} else {
+				*block = atoi(options[OPT_ROLLOVER].o_request);
 			}
 
-			*block = atoi(options[OPT_ROLLOVER].o_request);
 			ts->rollovers++;
 		}
 		gettimeofday(&(ts->tstop), NULL);
@@ -196,14 +198,16 @@ tftp_receive(int peer, uint16_t *block, 
 		(*block)++;
 		if (oldblock > *block) {
 			if (options[OPT_ROLLOVER].o_request == NULL) {
-				tftp_log(LOG_ERR,
-				    "Block rollover but not allowed.");
-				send_error(peer, EBADOP);
-				gettimeofday(&(ts->tstop), NULL);
-				return;
+				/*
+				 * "rollover" option not specified in
+				 * tftp client.  Default to rolling block
+				 * counter to 0.
+				 */
+				*block = 0;
+			} else {
+				*block = atoi(options[OPT_ROLLOVER].o_request);
 			}
 
-			*block = atoi(options[OPT_ROLLOVER].o_request);
 			ts->rollovers++;
 		}