[PATCH] Fix bug #9572 - File corruption during SMB1 read by Mac OSX 10.8.2 clients.

[Jeremy Allison]

On Thu, Jan 24, 2013 at 09:34:41AM +0100, Stefan (metze) Metzmacher wrote:
> Hi Jeremy,
> 
> > -	if ((sconn->smb1.unix_info.client_cap_low & CIFS_UNIX_LARGE_READ_CAP) ||
> > -	    (get_remote_arch() == RA_SAMBA)) {
> > -		/*
> > -		 * This is Samba only behavior (up to Samba 3.6)!
> > -		 *
> > -		 * Windows 2008 R2 ignores the upper_size,
> > -		 * so we do unless unix extentions are active
> > -		 * or "smbclient" is talking to us.
> > -		 */
> 
> Can you add the this comment to your patch, it would be bad to
> loose this.
> 
> smbclient from 4.0 would not result in RA_SAMBA.
> 
> Otherwise the patches look good.

Ok, just to confirm - here is the ammended set.
I'll push to autobuild with your reviewed-by.

Jeremy.
-------------- next part --------------
>From 251a376c41ff4882d120c5b472e6d6080add975c Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Tue, 22 Jan 2013 12:38:28 -0800
Subject: [PATCH 1/2] Revert "s3:smbd: SMB ReadX with size > 0xffff should only
 possible for samba clients."

Part of fix for bug #9572 -  File corruption during SMB1 read by Mac OSX 10.8.2 clients

This reverts commit f8c26c16b82989e002b839fc9eba6386fc036f6a.
---
 source3/smbd/reply.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/source3/smbd/reply.c b/source3/smbd/reply.c
index b511025..210b701 100644
--- a/source3/smbd/reply.c
+++ b/source3/smbd/reply.c
@@ -3854,7 +3854,6 @@ nosendfile_read:
 
 void reply_read_and_X(struct smb_request *req)
 {
-	struct smbd_server_connection *sconn = req->sconn;
 	connection_struct *conn = req->conn;
 	files_struct *fsp;
 	off_t startpos;
@@ -3893,15 +3892,7 @@ void reply_read_and_X(struct smb_request *req)
 		return;
 	}
 
-	if ((sconn->smb1.unix_info.client_cap_low & CIFS_UNIX_LARGE_READ_CAP) ||
-	    (get_remote_arch() == RA_SAMBA)) {
-		/*
-		 * This is Samba only behavior (up to Samba 3.6)!
-		 *
-		 * Windows 2008 R2 ignores the upper_size,
-		 * so we do unless unix extentions are active
-		 * or "smbclient" is talking to us.
-		 */
+	if (global_client_caps & CAP_LARGE_READX) {
 		size_t upper_size = SVAL(req->vwv+7, 0);
 		smb_maxcnt |= (upper_size<<16);
 		if (upper_size > 1) {
-- 
1.8.1


>From 336e7582d09e18b4d0e4354e0271bf4675b80f44 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Wed, 23 Jan 2013 09:57:50 -0800
Subject: [PATCH 2/2] Fix bug #9572 - File corruption during SMB1 read by Mac
 OSX 10.8.2 clients.

Accept a large read if we told the client we have UNIX extensions
and the client sent a non-zero upper 16-bit size.

Do the non-zero upper 16-bit size check first to save a function
call in what is a hot path.

Signed-off-by: Jeremy Allison <jra at samba.org>
---
 source3/smbd/reply.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/source3/smbd/reply.c b/source3/smbd/reply.c
index 210b701..6e1cd27 100644
--- a/source3/smbd/reply.c
+++ b/source3/smbd/reply.c
@@ -3849,6 +3849,26 @@ nosendfile_read:
 }
 
 /****************************************************************************
+ MacOSX clients send large reads without telling us they are going to do that.
+ Bug #9572 - File corruption during SMB1 read by Mac OSX 10.8.2 clients
+ Allow this if we are talking to a Samba client, or if we told the client
+ we supported this.
+****************************************************************************/
+
+static bool server_will_accept_large_read(void)
+{
+	/* Samba client ? No problem. */
+	if (get_remote_arch() == RA_SAMBA) {
+		return true;
+	}
+	/* Need UNIX extensions. */
+	if (!lp_unix_extensions()) {
+		return false;
+	}
+	return true;
+}
+
+/****************************************************************************
  Reply to a read and X.
 ****************************************************************************/
 
@@ -3858,6 +3878,7 @@ void reply_read_and_X(struct smb_request *req)
 	files_struct *fsp;
 	off_t startpos;
 	size_t smb_maxcnt;
+	size_t upper_size;
 	bool big_readX = False;
 #if 0
 	size_t smb_mincnt = SVAL(req->vwv+6, 0);
@@ -3892,8 +3913,15 @@ void reply_read_and_X(struct smb_request *req)
 		return;
 	}
 
-	if (global_client_caps & CAP_LARGE_READX) {
-		size_t upper_size = SVAL(req->vwv+7, 0);
+	upper_size = SVAL(req->vwv+7, 0);
+	if ((upper_size != 0) && server_will_accept_large_read()) {
+		/*
+		 * This is Samba only behavior (up to Samba 3.6)!
+		 *
+		 * Windows 2008 R2 ignores the upper_size,
+		 * so we do unless unix extentions are active
+		 * or "smbclient" is talking to us.
+		 */
 		smb_maxcnt |= (upper_size<<16);
 		if (upper_size > 1) {
 			/* Can't do this on a chained packet. */
-- 
1.8.1